1457c8996SThomas Gleixner // SPDX-License-Identifier: GPL-2.0-only 21da177e4SLinus Torvalds /* 31da177e4SLinus Torvalds * mm/mmap.c 41da177e4SLinus Torvalds * 51da177e4SLinus Torvalds * Written by obz. 61da177e4SLinus Torvalds * 7046c6884SAlan Cox * Address space accounting code <alan@lxorguk.ukuu.org.uk> 81da177e4SLinus Torvalds */ 91da177e4SLinus Torvalds 10b1de0d13SMitchel Humpherys #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 11b1de0d13SMitchel Humpherys 12e8420a8eSCyril Hrubis #include <linux/kernel.h> 131da177e4SLinus Torvalds #include <linux/slab.h> 144af3c9ccSAlexey Dobriyan #include <linux/backing-dev.h> 151da177e4SLinus Torvalds #include <linux/mm.h> 1617fca131SArnd Bergmann #include <linux/mm_inline.h> 171da177e4SLinus Torvalds #include <linux/shm.h> 181da177e4SLinus Torvalds #include <linux/mman.h> 191da177e4SLinus Torvalds #include <linux/pagemap.h> 201da177e4SLinus Torvalds #include <linux/swap.h> 211da177e4SLinus Torvalds #include <linux/syscalls.h> 22c59ede7bSRandy.Dunlap #include <linux/capability.h> 231da177e4SLinus Torvalds #include <linux/init.h> 241da177e4SLinus Torvalds #include <linux/file.h> 251da177e4SLinus Torvalds #include <linux/fs.h> 261da177e4SLinus Torvalds #include <linux/personality.h> 271da177e4SLinus Torvalds #include <linux/security.h> 281da177e4SLinus Torvalds #include <linux/hugetlb.h> 29c01d5b30SHugh Dickins #include <linux/shmem_fs.h> 301da177e4SLinus Torvalds #include <linux/profile.h> 31b95f1b31SPaul Gortmaker #include <linux/export.h> 321da177e4SLinus Torvalds #include <linux/mount.h> 331da177e4SLinus Torvalds #include <linux/mempolicy.h> 341da177e4SLinus Torvalds #include <linux/rmap.h> 35cddb8a5cSAndrea Arcangeli #include <linux/mmu_notifier.h> 3682f71ae4SKonstantin Khlebnikov #include <linux/mmdebug.h> 37cdd6c482SIngo Molnar #include <linux/perf_event.h> 38120a795dSAl Viro #include <linux/audit.h> 39b15d00b6SAndrea Arcangeli #include <linux/khugepaged.h> 402b144498SSrikar Dronamraju #include <linux/uprobes.h> 411640879aSAndrew Shewmaker #include <linux/notifier.h> 421640879aSAndrew Shewmaker #include <linux/memory.h> 43b1de0d13SMitchel Humpherys #include <linux/printk.h> 4419a809afSAndrea Arcangeli #include <linux/userfaultfd_k.h> 45d977d56cSKonstantin Khlebnikov #include <linux/moduleparam.h> 4662b5f7d0SDave Hansen #include <linux/pkeys.h> 4721292580SAndrea Arcangeli #include <linux/oom.h> 4804f5866eSAndrea Arcangeli #include <linux/sched/mm.h> 491da177e4SLinus Torvalds 507c0f6ba6SLinus Torvalds #include <linux/uaccess.h> 511da177e4SLinus Torvalds #include <asm/cacheflush.h> 521da177e4SLinus Torvalds #include <asm/tlb.h> 53d6dd61c8SJeremy Fitzhardinge #include <asm/mmu_context.h> 541da177e4SLinus Torvalds 55df529cabSJaewon Kim #define CREATE_TRACE_POINTS 56df529cabSJaewon Kim #include <trace/events/mmap.h> 57df529cabSJaewon Kim 5842b77728SJan Beulich #include "internal.h" 5942b77728SJan Beulich 603a459756SKirill Korotaev #ifndef arch_mmap_check 613a459756SKirill Korotaev #define arch_mmap_check(addr, len, flags) (0) 623a459756SKirill Korotaev #endif 633a459756SKirill Korotaev 64d07e2259SDaniel Cashman #ifdef CONFIG_HAVE_ARCH_MMAP_RND_BITS 65d07e2259SDaniel Cashman const int mmap_rnd_bits_min = CONFIG_ARCH_MMAP_RND_BITS_MIN; 66d07e2259SDaniel Cashman const int mmap_rnd_bits_max = CONFIG_ARCH_MMAP_RND_BITS_MAX; 67d07e2259SDaniel Cashman int mmap_rnd_bits __read_mostly = CONFIG_ARCH_MMAP_RND_BITS; 68d07e2259SDaniel Cashman #endif 69d07e2259SDaniel Cashman #ifdef CONFIG_HAVE_ARCH_MMAP_RND_COMPAT_BITS 70d07e2259SDaniel Cashman const int mmap_rnd_compat_bits_min = CONFIG_ARCH_MMAP_RND_COMPAT_BITS_MIN; 71d07e2259SDaniel Cashman const int mmap_rnd_compat_bits_max = CONFIG_ARCH_MMAP_RND_COMPAT_BITS_MAX; 72d07e2259SDaniel Cashman int mmap_rnd_compat_bits __read_mostly = CONFIG_ARCH_MMAP_RND_COMPAT_BITS; 73d07e2259SDaniel Cashman #endif 74d07e2259SDaniel Cashman 75f4fcd558SKonstantin Khlebnikov static bool ignore_rlimit_data; 76d977d56cSKonstantin Khlebnikov core_param(ignore_rlimit_data, ignore_rlimit_data, bool, 0644); 77d07e2259SDaniel Cashman 78763ecb03SLiam R. Howlett static void unmap_region(struct mm_struct *mm, struct maple_tree *mt, 79e0da382cSHugh Dickins struct vm_area_struct *vma, struct vm_area_struct *prev, 80763ecb03SLiam R. Howlett struct vm_area_struct *next, unsigned long start, 81763ecb03SLiam R. Howlett unsigned long end); 82e0da382cSHugh Dickins 8364e45507SPeter Feiner static pgprot_t vm_pgprot_modify(pgprot_t oldprot, unsigned long vm_flags) 8464e45507SPeter Feiner { 8564e45507SPeter Feiner return pgprot_modify(oldprot, vm_get_page_prot(vm_flags)); 8664e45507SPeter Feiner } 8764e45507SPeter Feiner 8864e45507SPeter Feiner /* Update vma->vm_page_prot to reflect vma->vm_flags. */ 8964e45507SPeter Feiner void vma_set_page_prot(struct vm_area_struct *vma) 9064e45507SPeter Feiner { 9164e45507SPeter Feiner unsigned long vm_flags = vma->vm_flags; 926d2329f8SAndrea Arcangeli pgprot_t vm_page_prot; 9364e45507SPeter Feiner 946d2329f8SAndrea Arcangeli vm_page_prot = vm_pgprot_modify(vma->vm_page_prot, vm_flags); 956d2329f8SAndrea Arcangeli if (vma_wants_writenotify(vma, vm_page_prot)) { 9664e45507SPeter Feiner vm_flags &= ~VM_SHARED; 976d2329f8SAndrea Arcangeli vm_page_prot = vm_pgprot_modify(vm_page_prot, vm_flags); 9864e45507SPeter Feiner } 99c1e8d7c6SMichel Lespinasse /* remove_protection_ptes reads vma->vm_page_prot without mmap_lock */ 1006d2329f8SAndrea Arcangeli WRITE_ONCE(vma->vm_page_prot, vm_page_prot); 10164e45507SPeter Feiner } 10264e45507SPeter Feiner 1031da177e4SLinus Torvalds /* 104c8c06efaSDavidlohr Bueso * Requires inode->i_mapping->i_mmap_rwsem 1051da177e4SLinus Torvalds */ 1061da177e4SLinus Torvalds static void __remove_shared_vm_struct(struct vm_area_struct *vma, 1071da177e4SLinus Torvalds struct file *file, struct address_space *mapping) 1081da177e4SLinus Torvalds { 1091da177e4SLinus Torvalds if (vma->vm_flags & VM_SHARED) 1104bb5f5d9SDavid Herrmann mapping_unmap_writable(mapping); 1111da177e4SLinus Torvalds 1121da177e4SLinus Torvalds flush_dcache_mmap_lock(mapping); 1136b2dbba8SMichel Lespinasse vma_interval_tree_remove(vma, &mapping->i_mmap); 1141da177e4SLinus Torvalds flush_dcache_mmap_unlock(mapping); 1151da177e4SLinus Torvalds } 1161da177e4SLinus Torvalds 1171da177e4SLinus Torvalds /* 1186b2dbba8SMichel Lespinasse * Unlink a file-based vm structure from its interval tree, to hide 119a8fb5618SHugh Dickins * vma from rmap and vmtruncate before freeing its page tables. 1201da177e4SLinus Torvalds */ 121a8fb5618SHugh Dickins void unlink_file_vma(struct vm_area_struct *vma) 1221da177e4SLinus Torvalds { 1231da177e4SLinus Torvalds struct file *file = vma->vm_file; 1241da177e4SLinus Torvalds 1251da177e4SLinus Torvalds if (file) { 1261da177e4SLinus Torvalds struct address_space *mapping = file->f_mapping; 12783cde9e8SDavidlohr Bueso i_mmap_lock_write(mapping); 1281da177e4SLinus Torvalds __remove_shared_vm_struct(vma, file, mapping); 12983cde9e8SDavidlohr Bueso i_mmap_unlock_write(mapping); 1301da177e4SLinus Torvalds } 131a8fb5618SHugh Dickins } 132a8fb5618SHugh Dickins 133a8fb5618SHugh Dickins /* 134763ecb03SLiam R. Howlett * Close a vm structure and free it. 135a8fb5618SHugh Dickins */ 136763ecb03SLiam R. Howlett static void remove_vma(struct vm_area_struct *vma) 137a8fb5618SHugh Dickins { 138a8fb5618SHugh Dickins might_sleep(); 1391da177e4SLinus Torvalds if (vma->vm_ops && vma->vm_ops->close) 1401da177e4SLinus Torvalds vma->vm_ops->close(vma); 141e9714acfSKonstantin Khlebnikov if (vma->vm_file) 142a8fb5618SHugh Dickins fput(vma->vm_file); 143f0be3d32SLee Schermerhorn mpol_put(vma_policy(vma)); 1443928d4f5SLinus Torvalds vm_area_free(vma); 1451da177e4SLinus Torvalds } 1461da177e4SLinus Torvalds 147b62b633eSLiam R. Howlett static inline struct vm_area_struct *vma_prev_limit(struct vma_iterator *vmi, 148b62b633eSLiam R. Howlett unsigned long min) 149b62b633eSLiam R. Howlett { 150b62b633eSLiam R. Howlett return mas_prev(&vmi->mas, min); 151b62b633eSLiam R. Howlett } 152b62b633eSLiam R. Howlett 153b62b633eSLiam R. Howlett static inline int vma_iter_clear_gfp(struct vma_iterator *vmi, 154b62b633eSLiam R. Howlett unsigned long start, unsigned long end, gfp_t gfp) 155b62b633eSLiam R. Howlett { 156b62b633eSLiam R. Howlett vmi->mas.index = start; 157b62b633eSLiam R. Howlett vmi->mas.last = end - 1; 158b62b633eSLiam R. Howlett mas_store_gfp(&vmi->mas, NULL, gfp); 159b62b633eSLiam R. Howlett if (unlikely(mas_is_err(&vmi->mas))) 160b62b633eSLiam R. Howlett return -ENOMEM; 161b62b633eSLiam R. Howlett 162b62b633eSLiam R. Howlett return 0; 163b62b633eSLiam R. Howlett } 164b62b633eSLiam R. Howlett 1652e7ce7d3SLiam R. Howlett /* 1662e7ce7d3SLiam R. Howlett * check_brk_limits() - Use platform specific check of range & verify mlock 1672e7ce7d3SLiam R. Howlett * limits. 1682e7ce7d3SLiam R. Howlett * @addr: The address to check 1692e7ce7d3SLiam R. Howlett * @len: The size of increase. 1702e7ce7d3SLiam R. Howlett * 1712e7ce7d3SLiam R. Howlett * Return: 0 on success. 1722e7ce7d3SLiam R. Howlett */ 1732e7ce7d3SLiam R. Howlett static int check_brk_limits(unsigned long addr, unsigned long len) 1742e7ce7d3SLiam R. Howlett { 1752e7ce7d3SLiam R. Howlett unsigned long mapped_addr; 1762e7ce7d3SLiam R. Howlett 1772e7ce7d3SLiam R. Howlett mapped_addr = get_unmapped_area(NULL, addr, len, 0, MAP_FIXED); 1782e7ce7d3SLiam R. Howlett if (IS_ERR_VALUE(mapped_addr)) 1792e7ce7d3SLiam R. Howlett return mapped_addr; 1802e7ce7d3SLiam R. Howlett 1812e7ce7d3SLiam R. Howlett return mlock_future_check(current->mm, current->mm->def_flags, len); 1822e7ce7d3SLiam R. Howlett } 18392fed820SLiam R. Howlett static int do_brk_flags(struct vma_iterator *vmi, struct vm_area_struct *brkvma, 184763ecb03SLiam R. Howlett unsigned long addr, unsigned long request, unsigned long flags); 1856a6160a7SHeiko Carstens SYSCALL_DEFINE1(brk, unsigned long, brk) 1861da177e4SLinus Torvalds { 1879bc8039eSYang Shi unsigned long newbrk, oldbrk, origbrk; 1881da177e4SLinus Torvalds struct mm_struct *mm = current->mm; 1892e7ce7d3SLiam R. Howlett struct vm_area_struct *brkvma, *next = NULL; 190a5b4592cSJiri Kosina unsigned long min_brk; 191128557ffSMichel Lespinasse bool populate; 1929bc8039eSYang Shi bool downgraded = false; 193897ab3e0SMike Rapoport LIST_HEAD(uf); 19492fed820SLiam R. Howlett struct vma_iterator vmi; 1951da177e4SLinus Torvalds 196d8ed45c5SMichel Lespinasse if (mmap_write_lock_killable(mm)) 197dc0ef0dfSMichal Hocko return -EINTR; 1981da177e4SLinus Torvalds 1999bc8039eSYang Shi origbrk = mm->brk; 2009bc8039eSYang Shi 201a5b4592cSJiri Kosina #ifdef CONFIG_COMPAT_BRK 2025520e894SJiri Kosina /* 2035520e894SJiri Kosina * CONFIG_COMPAT_BRK can still be overridden by setting 2045520e894SJiri Kosina * randomize_va_space to 2, which will still cause mm->start_brk 2055520e894SJiri Kosina * to be arbitrarily shifted 2065520e894SJiri Kosina */ 2074471a675SJiri Kosina if (current->brk_randomized) 2085520e894SJiri Kosina min_brk = mm->start_brk; 2095520e894SJiri Kosina else 2105520e894SJiri Kosina min_brk = mm->end_data; 211a5b4592cSJiri Kosina #else 212a5b4592cSJiri Kosina min_brk = mm->start_brk; 213a5b4592cSJiri Kosina #endif 214a5b4592cSJiri Kosina if (brk < min_brk) 2151da177e4SLinus Torvalds goto out; 2161e624196SRam Gupta 2171e624196SRam Gupta /* 2181e624196SRam Gupta * Check against rlimit here. If this check is done later after the test 2191e624196SRam Gupta * of oldbrk with newbrk then it can escape the test and let the data 2201e624196SRam Gupta * segment grow beyond its set limit the in case where the limit is 2211e624196SRam Gupta * not page aligned -Ram Gupta 2221e624196SRam Gupta */ 2238764b338SCyrill Gorcunov if (check_data_rlimit(rlimit(RLIMIT_DATA), brk, mm->start_brk, 2248764b338SCyrill Gorcunov mm->end_data, mm->start_data)) 2251e624196SRam Gupta goto out; 2261e624196SRam Gupta 2271da177e4SLinus Torvalds newbrk = PAGE_ALIGN(brk); 2281da177e4SLinus Torvalds oldbrk = PAGE_ALIGN(mm->brk); 2299bc8039eSYang Shi if (oldbrk == newbrk) { 2309bc8039eSYang Shi mm->brk = brk; 2319bc8039eSYang Shi goto success; 2329bc8039eSYang Shi } 2331da177e4SLinus Torvalds 2349bc8039eSYang Shi /* 2359bc8039eSYang Shi * Always allow shrinking brk. 23627b26701SLiam R. Howlett * do_vma_munmap() may downgrade mmap_lock to read. 2379bc8039eSYang Shi */ 2381da177e4SLinus Torvalds if (brk <= mm->brk) { 2399bc8039eSYang Shi int ret; 2409bc8039eSYang Shi 2412e7ce7d3SLiam R. Howlett /* Search one past newbrk */ 24292fed820SLiam R. Howlett vma_iter_init(&vmi, mm, newbrk); 24392fed820SLiam R. Howlett brkvma = vma_find(&vmi, oldbrk); 244f5ad5083SJason A. Donenfeld if (!brkvma || brkvma->vm_start >= oldbrk) 2452e7ce7d3SLiam R. Howlett goto out; /* mapping intersects with an existing non-brk vma. */ 2469bc8039eSYang Shi /* 2472e7ce7d3SLiam R. Howlett * mm->brk must be protected by write mmap_lock. 24827b26701SLiam R. Howlett * do_vma_munmap() may downgrade the lock, so update it 24927b26701SLiam R. Howlett * before calling do_vma_munmap(). 2509bc8039eSYang Shi */ 2519bc8039eSYang Shi mm->brk = brk; 25227b26701SLiam R. Howlett ret = do_vma_munmap(&vmi, brkvma, newbrk, oldbrk, &uf, true); 2532e7ce7d3SLiam R. Howlett if (ret == 1) { 2542e7ce7d3SLiam R. Howlett downgraded = true; 2552e7ce7d3SLiam R. Howlett goto success; 2562e7ce7d3SLiam R. Howlett } else if (!ret) 2572e7ce7d3SLiam R. Howlett goto success; 2582e7ce7d3SLiam R. Howlett 2599bc8039eSYang Shi mm->brk = origbrk; 2601da177e4SLinus Torvalds goto out; 2611da177e4SLinus Torvalds } 2621da177e4SLinus Torvalds 2632e7ce7d3SLiam R. Howlett if (check_brk_limits(oldbrk, newbrk - oldbrk)) 2642e7ce7d3SLiam R. Howlett goto out; 2652e7ce7d3SLiam R. Howlett 2662e7ce7d3SLiam R. Howlett /* 2672e7ce7d3SLiam R. Howlett * Only check if the next VMA is within the stack_guard_gap of the 2682e7ce7d3SLiam R. Howlett * expansion area 2692e7ce7d3SLiam R. Howlett */ 27092fed820SLiam R. Howlett vma_iter_init(&vmi, mm, oldbrk); 27192fed820SLiam R. Howlett next = vma_find(&vmi, newbrk + PAGE_SIZE + stack_guard_gap); 2721be7107fSHugh Dickins if (next && newbrk + PAGE_SIZE > vm_start_gap(next)) 2731da177e4SLinus Torvalds goto out; 2741da177e4SLinus Torvalds 27592fed820SLiam R. Howlett brkvma = vma_prev_limit(&vmi, mm->start_brk); 2761da177e4SLinus Torvalds /* Ok, looks good - let it rip. */ 27792fed820SLiam R. Howlett if (do_brk_flags(&vmi, brkvma, oldbrk, newbrk - oldbrk, 0) < 0) 2781da177e4SLinus Torvalds goto out; 2792e7ce7d3SLiam R. Howlett 2801da177e4SLinus Torvalds mm->brk = brk; 2819bc8039eSYang Shi 2829bc8039eSYang Shi success: 283128557ffSMichel Lespinasse populate = newbrk > oldbrk && (mm->def_flags & VM_LOCKED) != 0; 2849bc8039eSYang Shi if (downgraded) 285d8ed45c5SMichel Lespinasse mmap_read_unlock(mm); 2869bc8039eSYang Shi else 287d8ed45c5SMichel Lespinasse mmap_write_unlock(mm); 288897ab3e0SMike Rapoport userfaultfd_unmap_complete(mm, &uf); 289128557ffSMichel Lespinasse if (populate) 290128557ffSMichel Lespinasse mm_populate(oldbrk, newbrk - oldbrk); 291128557ffSMichel Lespinasse return brk; 292128557ffSMichel Lespinasse 2931da177e4SLinus Torvalds out: 294d8ed45c5SMichel Lespinasse mmap_write_unlock(mm); 295b7204006SAdrian Huang return origbrk; 2961da177e4SLinus Torvalds } 2971da177e4SLinus Torvalds 298d4af56c5SLiam R. Howlett #if defined(CONFIG_DEBUG_VM_MAPLE_TREE) 299d4af56c5SLiam R. Howlett extern void mt_validate(struct maple_tree *mt); 300d4af56c5SLiam R. Howlett extern void mt_dump(const struct maple_tree *mt); 3011da177e4SLinus Torvalds 302d4af56c5SLiam R. Howlett /* Validate the maple tree */ 303d4af56c5SLiam R. Howlett static void validate_mm_mt(struct mm_struct *mm) 304d4af56c5SLiam R. Howlett { 305d4af56c5SLiam R. Howlett struct maple_tree *mt = &mm->mm_mt; 306763ecb03SLiam R. Howlett struct vm_area_struct *vma_mt; 307d4af56c5SLiam R. Howlett 308d4af56c5SLiam R. Howlett MA_STATE(mas, mt, 0, 0); 309d4af56c5SLiam R. Howlett 310d4af56c5SLiam R. Howlett mt_validate(&mm->mm_mt); 311d4af56c5SLiam R. Howlett mas_for_each(&mas, vma_mt, ULONG_MAX) { 312763ecb03SLiam R. Howlett if ((vma_mt->vm_start != mas.index) || 313763ecb03SLiam R. Howlett (vma_mt->vm_end - 1 != mas.last)) { 314d4af56c5SLiam R. Howlett pr_emerg("issue in %s\n", current->comm); 315d4af56c5SLiam R. Howlett dump_stack(); 316d4af56c5SLiam R. Howlett dump_vma(vma_mt); 317d4af56c5SLiam R. Howlett pr_emerg("mt piv: %p %lu - %lu\n", vma_mt, 318d4af56c5SLiam R. Howlett mas.index, mas.last); 319d4af56c5SLiam R. Howlett pr_emerg("mt vma: %p %lu - %lu\n", vma_mt, 320d4af56c5SLiam R. Howlett vma_mt->vm_start, vma_mt->vm_end); 321d4af56c5SLiam R. Howlett 322d4af56c5SLiam R. Howlett mt_dump(mas.tree); 323d4af56c5SLiam R. Howlett if (vma_mt->vm_end != mas.last + 1) { 324d4af56c5SLiam R. Howlett pr_err("vma: %p vma_mt %lu-%lu\tmt %lu-%lu\n", 325d4af56c5SLiam R. Howlett mm, vma_mt->vm_start, vma_mt->vm_end, 326d4af56c5SLiam R. Howlett mas.index, mas.last); 327d4af56c5SLiam R. Howlett mt_dump(mas.tree); 328d4af56c5SLiam R. Howlett } 329d4af56c5SLiam R. Howlett VM_BUG_ON_MM(vma_mt->vm_end != mas.last + 1, mm); 330d4af56c5SLiam R. Howlett if (vma_mt->vm_start != mas.index) { 331d4af56c5SLiam R. Howlett pr_err("vma: %p vma_mt %p %lu - %lu doesn't match\n", 332d4af56c5SLiam R. Howlett mm, vma_mt, vma_mt->vm_start, vma_mt->vm_end); 333d4af56c5SLiam R. Howlett mt_dump(mas.tree); 334d4af56c5SLiam R. Howlett } 335d4af56c5SLiam R. Howlett VM_BUG_ON_MM(vma_mt->vm_start != mas.index, mm); 336d4af56c5SLiam R. Howlett } 337d4af56c5SLiam R. Howlett } 338d4af56c5SLiam R. Howlett } 3391da177e4SLinus Torvalds 340eafd4dc4SRashika Kheria static void validate_mm(struct mm_struct *mm) 3411da177e4SLinus Torvalds { 3421da177e4SLinus Torvalds int bug = 0; 3431da177e4SLinus Torvalds int i = 0; 344763ecb03SLiam R. Howlett struct vm_area_struct *vma; 345763ecb03SLiam R. Howlett MA_STATE(mas, &mm->mm_mt, 0, 0); 346ff26f70fSAndrew Morton 347524e00b3SLiam R. Howlett validate_mm_mt(mm); 348524e00b3SLiam R. Howlett 349763ecb03SLiam R. Howlett mas_for_each(&mas, vma, ULONG_MAX) { 350524e00b3SLiam R. Howlett #ifdef CONFIG_DEBUG_VM_RB 35112352d3cSKonstantin Khlebnikov struct anon_vma *anon_vma = vma->anon_vma; 352ed8ea815SMichel Lespinasse struct anon_vma_chain *avc; 353ff26f70fSAndrew Morton 35412352d3cSKonstantin Khlebnikov if (anon_vma) { 35512352d3cSKonstantin Khlebnikov anon_vma_lock_read(anon_vma); 356ed8ea815SMichel Lespinasse list_for_each_entry(avc, &vma->anon_vma_chain, same_vma) 357ed8ea815SMichel Lespinasse anon_vma_interval_tree_verify(avc); 35812352d3cSKonstantin Khlebnikov anon_vma_unlock_read(anon_vma); 35912352d3cSKonstantin Khlebnikov } 360524e00b3SLiam R. Howlett #endif 3611da177e4SLinus Torvalds i++; 3621da177e4SLinus Torvalds } 3635a0768f6SMichel Lespinasse if (i != mm->map_count) { 364763ecb03SLiam R. Howlett pr_emerg("map_count %d mas_for_each %d\n", mm->map_count, i); 3655a0768f6SMichel Lespinasse bug = 1; 3665a0768f6SMichel Lespinasse } 36796dad67fSSasha Levin VM_BUG_ON_MM(bug, mm); 3681da177e4SLinus Torvalds } 369524e00b3SLiam R. Howlett 370524e00b3SLiam R. Howlett #else /* !CONFIG_DEBUG_VM_MAPLE_TREE */ 371d4af56c5SLiam R. Howlett #define validate_mm_mt(root) do { } while (0) 3721da177e4SLinus Torvalds #define validate_mm(mm) do { } while (0) 373524e00b3SLiam R. Howlett #endif /* CONFIG_DEBUG_VM_MAPLE_TREE */ 374d3737187SMichel Lespinasse 375bf181b9fSMichel Lespinasse /* 376bf181b9fSMichel Lespinasse * vma has some anon_vma assigned, and is already inserted on that 377bf181b9fSMichel Lespinasse * anon_vma's interval trees. 378bf181b9fSMichel Lespinasse * 379bf181b9fSMichel Lespinasse * Before updating the vma's vm_start / vm_end / vm_pgoff fields, the 380bf181b9fSMichel Lespinasse * vma must be removed from the anon_vma's interval trees using 381bf181b9fSMichel Lespinasse * anon_vma_interval_tree_pre_update_vma(). 382bf181b9fSMichel Lespinasse * 383bf181b9fSMichel Lespinasse * After the update, the vma will be reinserted using 384bf181b9fSMichel Lespinasse * anon_vma_interval_tree_post_update_vma(). 385bf181b9fSMichel Lespinasse * 386c1e8d7c6SMichel Lespinasse * The entire update must be protected by exclusive mmap_lock and by 387bf181b9fSMichel Lespinasse * the root anon_vma's mutex. 388bf181b9fSMichel Lespinasse */ 389bf181b9fSMichel Lespinasse static inline void 390bf181b9fSMichel Lespinasse anon_vma_interval_tree_pre_update_vma(struct vm_area_struct *vma) 391bf181b9fSMichel Lespinasse { 392bf181b9fSMichel Lespinasse struct anon_vma_chain *avc; 393bf181b9fSMichel Lespinasse 394bf181b9fSMichel Lespinasse list_for_each_entry(avc, &vma->anon_vma_chain, same_vma) 395bf181b9fSMichel Lespinasse anon_vma_interval_tree_remove(avc, &avc->anon_vma->rb_root); 396bf181b9fSMichel Lespinasse } 397bf181b9fSMichel Lespinasse 398bf181b9fSMichel Lespinasse static inline void 399bf181b9fSMichel Lespinasse anon_vma_interval_tree_post_update_vma(struct vm_area_struct *vma) 400bf181b9fSMichel Lespinasse { 401bf181b9fSMichel Lespinasse struct anon_vma_chain *avc; 402bf181b9fSMichel Lespinasse 403bf181b9fSMichel Lespinasse list_for_each_entry(avc, &vma->anon_vma_chain, same_vma) 404bf181b9fSMichel Lespinasse anon_vma_interval_tree_insert(avc, &avc->anon_vma->rb_root); 405bf181b9fSMichel Lespinasse } 406bf181b9fSMichel Lespinasse 407e8420a8eSCyril Hrubis static unsigned long count_vma_pages_range(struct mm_struct *mm, 408e8420a8eSCyril Hrubis unsigned long addr, unsigned long end) 409e8420a8eSCyril Hrubis { 4102e3af1dbSMatthew Wilcox (Oracle) VMA_ITERATOR(vmi, mm, addr); 411e8420a8eSCyril Hrubis struct vm_area_struct *vma; 4122e3af1dbSMatthew Wilcox (Oracle) unsigned long nr_pages = 0; 413e8420a8eSCyril Hrubis 4142e3af1dbSMatthew Wilcox (Oracle) for_each_vma_range(vmi, vma, end) { 4152e3af1dbSMatthew Wilcox (Oracle) unsigned long vm_start = max(addr, vma->vm_start); 4162e3af1dbSMatthew Wilcox (Oracle) unsigned long vm_end = min(end, vma->vm_end); 417e8420a8eSCyril Hrubis 4182e3af1dbSMatthew Wilcox (Oracle) nr_pages += PHYS_PFN(vm_end - vm_start); 419e8420a8eSCyril Hrubis } 420e8420a8eSCyril Hrubis 421e8420a8eSCyril Hrubis return nr_pages; 422e8420a8eSCyril Hrubis } 423e8420a8eSCyril Hrubis 424c154124fSLiam R. Howlett static void __vma_link_file(struct vm_area_struct *vma, 425c154124fSLiam R. Howlett struct address_space *mapping) 4261da177e4SLinus Torvalds { 4271da177e4SLinus Torvalds if (vma->vm_flags & VM_SHARED) 428cf508b58SMiaohe Lin mapping_allow_writable(mapping); 4291da177e4SLinus Torvalds 4301da177e4SLinus Torvalds flush_dcache_mmap_lock(mapping); 4316b2dbba8SMichel Lespinasse vma_interval_tree_insert(vma, &mapping->i_mmap); 4321da177e4SLinus Torvalds flush_dcache_mmap_unlock(mapping); 4331da177e4SLinus Torvalds } 4341da177e4SLinus Torvalds 435d4af56c5SLiam R. Howlett /* 436d4af56c5SLiam R. Howlett * vma_mas_store() - Store a VMA in the maple tree. 437d4af56c5SLiam R. Howlett * @vma: The vm_area_struct 438d4af56c5SLiam R. Howlett * @mas: The maple state 439d4af56c5SLiam R. Howlett * 440d4af56c5SLiam R. Howlett * Efficient way to store a VMA in the maple tree when the @mas has already 441d4af56c5SLiam R. Howlett * walked to the correct location. 442d4af56c5SLiam R. Howlett * 443d4af56c5SLiam R. Howlett * Note: the end address is inclusive in the maple tree. 444d4af56c5SLiam R. Howlett */ 445d4af56c5SLiam R. Howlett void vma_mas_store(struct vm_area_struct *vma, struct ma_state *mas) 446d4af56c5SLiam R. Howlett { 447d4af56c5SLiam R. Howlett trace_vma_store(mas->tree, vma); 448d4af56c5SLiam R. Howlett mas_set_range(mas, vma->vm_start, vma->vm_end - 1); 449d4af56c5SLiam R. Howlett mas_store_prealloc(mas, vma); 450d4af56c5SLiam R. Howlett } 451d4af56c5SLiam R. Howlett 452d4af56c5SLiam R. Howlett /* 453d4af56c5SLiam R. Howlett * vma_mas_remove() - Remove a VMA from the maple tree. 454d4af56c5SLiam R. Howlett * @vma: The vm_area_struct 455d4af56c5SLiam R. Howlett * @mas: The maple state 456d4af56c5SLiam R. Howlett * 457d4af56c5SLiam R. Howlett * Efficient way to remove a VMA from the maple tree when the @mas has already 458d4af56c5SLiam R. Howlett * been established and points to the correct location. 459d4af56c5SLiam R. Howlett * Note: the end address is inclusive in the maple tree. 460d4af56c5SLiam R. Howlett */ 461d4af56c5SLiam R. Howlett void vma_mas_remove(struct vm_area_struct *vma, struct ma_state *mas) 462d4af56c5SLiam R. Howlett { 463d4af56c5SLiam R. Howlett trace_vma_mas_szero(mas->tree, vma->vm_start, vma->vm_end - 1); 464d4af56c5SLiam R. Howlett mas->index = vma->vm_start; 465d4af56c5SLiam R. Howlett mas->last = vma->vm_end - 1; 466d4af56c5SLiam R. Howlett mas_store_prealloc(mas, NULL); 467d4af56c5SLiam R. Howlett } 468d4af56c5SLiam R. Howlett 469d4af56c5SLiam R. Howlett /* 470d4af56c5SLiam R. Howlett * vma_mas_szero() - Set a given range to zero. Used when modifying a 471d4af56c5SLiam R. Howlett * vm_area_struct start or end. 472d4af56c5SLiam R. Howlett * 4734a423440SIan Cowan * @mas: The maple tree ma_state 474d4af56c5SLiam R. Howlett * @start: The start address to zero 475d4af56c5SLiam R. Howlett * @end: The end address to zero. 476d4af56c5SLiam R. Howlett */ 477d4af56c5SLiam R. Howlett static inline void vma_mas_szero(struct ma_state *mas, unsigned long start, 478d4af56c5SLiam R. Howlett unsigned long end) 479d4af56c5SLiam R. Howlett { 480d4af56c5SLiam R. Howlett trace_vma_mas_szero(mas->tree, start, end - 1); 481d4af56c5SLiam R. Howlett mas_set_range(mas, start, end - 1); 482d4af56c5SLiam R. Howlett mas_store_prealloc(mas, NULL); 483d4af56c5SLiam R. Howlett } 484d4af56c5SLiam R. Howlett 485763ecb03SLiam R. Howlett static int vma_link(struct mm_struct *mm, struct vm_area_struct *vma) 4861da177e4SLinus Torvalds { 48779e4f2caSLiam R. Howlett VMA_ITERATOR(vmi, mm, 0); 4881da177e4SLinus Torvalds struct address_space *mapping = NULL; 4891da177e4SLinus Torvalds 49079e4f2caSLiam R. Howlett if (vma_iter_prealloc(&vmi)) 491d4af56c5SLiam R. Howlett return -ENOMEM; 492d4af56c5SLiam R. Howlett 49364ac4940SHuang Shijie if (vma->vm_file) { 4941da177e4SLinus Torvalds mapping = vma->vm_file->f_mapping; 49583cde9e8SDavidlohr Bueso i_mmap_lock_write(mapping); 49664ac4940SHuang Shijie } 4971da177e4SLinus Torvalds 49879e4f2caSLiam R. Howlett vma_iter_store(&vmi, vma); 4991da177e4SLinus Torvalds 500c154124fSLiam R. Howlett if (mapping) { 501c154124fSLiam R. Howlett __vma_link_file(vma, mapping); 50283cde9e8SDavidlohr Bueso i_mmap_unlock_write(mapping); 503c154124fSLiam R. Howlett } 5041da177e4SLinus Torvalds 5051da177e4SLinus Torvalds mm->map_count++; 5061da177e4SLinus Torvalds validate_mm(mm); 507d4af56c5SLiam R. Howlett return 0; 5081da177e4SLinus Torvalds } 5091da177e4SLinus Torvalds 5101da177e4SLinus Torvalds /* 5114dd1b841SLiam R. Howlett * vma_expand - Expand an existing VMA 5124dd1b841SLiam R. Howlett * 5134dd1b841SLiam R. Howlett * @mas: The maple state 5144dd1b841SLiam R. Howlett * @vma: The vma to expand 5154dd1b841SLiam R. Howlett * @start: The start of the vma 5164dd1b841SLiam R. Howlett * @end: The exclusive end of the vma 5174dd1b841SLiam R. Howlett * @pgoff: The page offset of vma 5184dd1b841SLiam R. Howlett * @next: The current of next vma. 5194dd1b841SLiam R. Howlett * 5204dd1b841SLiam R. Howlett * Expand @vma to @start and @end. Can expand off the start and end. Will 5214dd1b841SLiam R. Howlett * expand over @next if it's different from @vma and @end == @next->vm_end. 5224dd1b841SLiam R. Howlett * Checking if the @vma can expand and merge with @next needs to be handled by 5234dd1b841SLiam R. Howlett * the caller. 5244dd1b841SLiam R. Howlett * 5254dd1b841SLiam R. Howlett * Returns: 0 on success 5264dd1b841SLiam R. Howlett */ 5273c441ab7SLiam R. Howlett inline int vma_expand(struct vma_iterator *vmi, struct vm_area_struct *vma, 5284dd1b841SLiam R. Howlett unsigned long start, unsigned long end, pgoff_t pgoff, 5294dd1b841SLiam R. Howlett struct vm_area_struct *next) 5304dd1b841SLiam R. Howlett { 5314dd1b841SLiam R. Howlett struct mm_struct *mm = vma->vm_mm; 5324dd1b841SLiam R. Howlett struct address_space *mapping = NULL; 5334dd1b841SLiam R. Howlett struct rb_root_cached *root = NULL; 5344dd1b841SLiam R. Howlett struct anon_vma *anon_vma = vma->anon_vma; 5354dd1b841SLiam R. Howlett struct file *file = vma->vm_file; 5364dd1b841SLiam R. Howlett bool remove_next = false; 5374dd1b841SLiam R. Howlett 5384dd1b841SLiam R. Howlett if (next && (vma != next) && (end == next->vm_end)) { 5394dd1b841SLiam R. Howlett remove_next = true; 5404dd1b841SLiam R. Howlett if (next->anon_vma && !vma->anon_vma) { 5414dd1b841SLiam R. Howlett int error; 5424dd1b841SLiam R. Howlett 5434dd1b841SLiam R. Howlett anon_vma = next->anon_vma; 5444dd1b841SLiam R. Howlett vma->anon_vma = anon_vma; 5454dd1b841SLiam R. Howlett error = anon_vma_clone(vma, next); 5464dd1b841SLiam R. Howlett if (error) 5474dd1b841SLiam R. Howlett return error; 5484dd1b841SLiam R. Howlett } 5494dd1b841SLiam R. Howlett } 5504dd1b841SLiam R. Howlett 5514dd1b841SLiam R. Howlett /* Not merging but overwriting any part of next is not handled. */ 5524dd1b841SLiam R. Howlett VM_BUG_ON(next && !remove_next && next != vma && end > next->vm_start); 5534dd1b841SLiam R. Howlett /* Only handles expanding */ 5544dd1b841SLiam R. Howlett VM_BUG_ON(vma->vm_start < start || vma->vm_end > end); 5554dd1b841SLiam R. Howlett 5563c441ab7SLiam R. Howlett if (vma_iter_prealloc(vmi)) 5574dd1b841SLiam R. Howlett goto nomem; 5584dd1b841SLiam R. Howlett 5594dd1b841SLiam R. Howlett vma_adjust_trans_huge(vma, start, end, 0); 5604dd1b841SLiam R. Howlett 5614dd1b841SLiam R. Howlett if (file) { 5624dd1b841SLiam R. Howlett mapping = file->f_mapping; 5634dd1b841SLiam R. Howlett root = &mapping->i_mmap; 5644dd1b841SLiam R. Howlett uprobe_munmap(vma, vma->vm_start, vma->vm_end); 5654dd1b841SLiam R. Howlett i_mmap_lock_write(mapping); 5664dd1b841SLiam R. Howlett } 5674dd1b841SLiam R. Howlett 5684dd1b841SLiam R. Howlett if (anon_vma) { 5694dd1b841SLiam R. Howlett anon_vma_lock_write(anon_vma); 5704dd1b841SLiam R. Howlett anon_vma_interval_tree_pre_update_vma(vma); 5714dd1b841SLiam R. Howlett } 5724dd1b841SLiam R. Howlett 5734dd1b841SLiam R. Howlett if (file) { 5744dd1b841SLiam R. Howlett flush_dcache_mmap_lock(mapping); 5754dd1b841SLiam R. Howlett vma_interval_tree_remove(vma, root); 5764dd1b841SLiam R. Howlett } 5774dd1b841SLiam R. Howlett 5784dd1b841SLiam R. Howlett vma->vm_start = start; 5794dd1b841SLiam R. Howlett vma->vm_end = end; 5804dd1b841SLiam R. Howlett vma->vm_pgoff = pgoff; 5813c441ab7SLiam R. Howlett vma_iter_store(vmi, vma); 5824dd1b841SLiam R. Howlett 5834dd1b841SLiam R. Howlett if (file) { 5844dd1b841SLiam R. Howlett vma_interval_tree_insert(vma, root); 5854dd1b841SLiam R. Howlett flush_dcache_mmap_unlock(mapping); 5864dd1b841SLiam R. Howlett } 5874dd1b841SLiam R. Howlett 5884dd1b841SLiam R. Howlett /* Expanding over the next vma */ 589763ecb03SLiam R. Howlett if (remove_next && file) { 5904dd1b841SLiam R. Howlett __remove_shared_vm_struct(next, file, mapping); 5914dd1b841SLiam R. Howlett } 5924dd1b841SLiam R. Howlett 5934dd1b841SLiam R. Howlett if (anon_vma) { 5944dd1b841SLiam R. Howlett anon_vma_interval_tree_post_update_vma(vma); 5954dd1b841SLiam R. Howlett anon_vma_unlock_write(anon_vma); 5964dd1b841SLiam R. Howlett } 5974dd1b841SLiam R. Howlett 5984dd1b841SLiam R. Howlett if (file) { 5994dd1b841SLiam R. Howlett i_mmap_unlock_write(mapping); 6004dd1b841SLiam R. Howlett uprobe_mmap(vma); 6014dd1b841SLiam R. Howlett } 6024dd1b841SLiam R. Howlett 6034dd1b841SLiam R. Howlett if (remove_next) { 6044dd1b841SLiam R. Howlett if (file) { 6054dd1b841SLiam R. Howlett uprobe_munmap(next, next->vm_start, next->vm_end); 6064dd1b841SLiam R. Howlett fput(file); 6074dd1b841SLiam R. Howlett } 6084dd1b841SLiam R. Howlett if (next->anon_vma) 6094dd1b841SLiam R. Howlett anon_vma_merge(vma, next); 6104dd1b841SLiam R. Howlett mm->map_count--; 6114dd1b841SLiam R. Howlett mpol_put(vma_policy(next)); 6124dd1b841SLiam R. Howlett vm_area_free(next); 6134dd1b841SLiam R. Howlett } 6144dd1b841SLiam R. Howlett 6154dd1b841SLiam R. Howlett validate_mm(mm); 6164dd1b841SLiam R. Howlett return 0; 6174dd1b841SLiam R. Howlett 6184dd1b841SLiam R. Howlett nomem: 6194dd1b841SLiam R. Howlett return -ENOMEM; 6204dd1b841SLiam R. Howlett } 6214dd1b841SLiam R. Howlett 6224dd1b841SLiam R. Howlett /* 6231da177e4SLinus Torvalds * We cannot adjust vm_start, vm_end, vm_pgoff fields of a vma that 6241da177e4SLinus Torvalds * is already present in an i_mmap tree without adjusting the tree. 6251da177e4SLinus Torvalds * The following helper function should be used when such adjustments 6261da177e4SLinus Torvalds * are necessary. The "insert" vma (if any) is to be inserted 6271da177e4SLinus Torvalds * before we drop the necessary locks. 6281da177e4SLinus Torvalds */ 629e86f15eeSAndrea Arcangeli int __vma_adjust(struct vm_area_struct *vma, unsigned long start, 630e86f15eeSAndrea Arcangeli unsigned long end, pgoff_t pgoff, struct vm_area_struct *insert, 631e86f15eeSAndrea Arcangeli struct vm_area_struct *expand) 6321da177e4SLinus Torvalds { 6331da177e4SLinus Torvalds struct mm_struct *mm = vma->vm_mm; 6341cd916d0SAndrew Morton struct vm_area_struct *next_next = NULL; /* uninit var warning */ 6351cd916d0SAndrew Morton struct vm_area_struct *next = find_vma(mm, vma->vm_end); 636524e00b3SLiam R. Howlett struct vm_area_struct *orig_vma = vma; 6371da177e4SLinus Torvalds struct address_space *mapping = NULL; 638f808c13fSDavidlohr Bueso struct rb_root_cached *root = NULL; 639012f1800SRik van Riel struct anon_vma *anon_vma = NULL; 6401da177e4SLinus Torvalds struct file *file = vma->vm_file; 641524e00b3SLiam R. Howlett bool vma_changed = false; 6421da177e4SLinus Torvalds long adjust_next = 0; 6431da177e4SLinus Torvalds int remove_next = 0; 644d4af56c5SLiam R. Howlett MA_STATE(mas, &mm->mm_mt, 0, 0); 645734537c9SKirill A. Shutemov struct vm_area_struct *exporter = NULL, *importer = NULL; 646287d97acSLinus Torvalds 647d4af56c5SLiam R. Howlett if (next && !insert) { 6481da177e4SLinus Torvalds if (end >= next->vm_end) { 6491da177e4SLinus Torvalds /* 6501da177e4SLinus Torvalds * vma expands, overlapping all the next, and 6511da177e4SLinus Torvalds * perhaps the one after too (mprotect case 6). 65286d12e47SAndrea Arcangeli * The only other cases that gets here are 653e86f15eeSAndrea Arcangeli * case 1, case 7 and case 8. 654e86f15eeSAndrea Arcangeli */ 655e86f15eeSAndrea Arcangeli if (next == expand) { 656e86f15eeSAndrea Arcangeli /* 657e86f15eeSAndrea Arcangeli * The only case where we don't expand "vma" 658e86f15eeSAndrea Arcangeli * and we expand "next" instead is case 8. 659e86f15eeSAndrea Arcangeli */ 660e86f15eeSAndrea Arcangeli VM_WARN_ON(end != next->vm_end); 661e86f15eeSAndrea Arcangeli /* 662e86f15eeSAndrea Arcangeli * remove_next == 3 means we're 663e86f15eeSAndrea Arcangeli * removing "vma" and that to do so we 664e86f15eeSAndrea Arcangeli * swapped "vma" and "next". 665e86f15eeSAndrea Arcangeli */ 666e86f15eeSAndrea Arcangeli remove_next = 3; 667e86f15eeSAndrea Arcangeli VM_WARN_ON(file != next->vm_file); 668e86f15eeSAndrea Arcangeli swap(vma, next); 669e86f15eeSAndrea Arcangeli } else { 670e86f15eeSAndrea Arcangeli VM_WARN_ON(expand != vma); 671e86f15eeSAndrea Arcangeli /* 672e86f15eeSAndrea Arcangeli * case 1, 6, 7, remove_next == 2 is case 6, 673e86f15eeSAndrea Arcangeli * remove_next == 1 is case 1 or 7. 6741da177e4SLinus Torvalds */ 675734537c9SKirill A. Shutemov remove_next = 1 + (end > next->vm_end); 676d4af56c5SLiam R. Howlett if (remove_next == 2) 677d4af56c5SLiam R. Howlett next_next = find_vma(mm, next->vm_end); 678d4af56c5SLiam R. Howlett 679e86f15eeSAndrea Arcangeli VM_WARN_ON(remove_next == 2 && 680763ecb03SLiam R. Howlett end != next_next->vm_end); 681e86f15eeSAndrea Arcangeli } 682e86f15eeSAndrea Arcangeli 683287d97acSLinus Torvalds exporter = next; 6841da177e4SLinus Torvalds importer = vma; 685734537c9SKirill A. Shutemov 686734537c9SKirill A. Shutemov /* 687734537c9SKirill A. Shutemov * If next doesn't have anon_vma, import from vma after 688734537c9SKirill A. Shutemov * next, if the vma overlaps with it. 689734537c9SKirill A. Shutemov */ 69097a42cd4SAndrea Arcangeli if (remove_next == 2 && !next->anon_vma) 691763ecb03SLiam R. Howlett exporter = next_next; 692734537c9SKirill A. Shutemov 6931da177e4SLinus Torvalds } else if (end > next->vm_start) { 6941da177e4SLinus Torvalds /* 6951da177e4SLinus Torvalds * vma expands, overlapping part of the next: 6961da177e4SLinus Torvalds * mprotect case 5 shifting the boundary up. 6971da177e4SLinus Torvalds */ 698f9d86a60SWei Yang adjust_next = (end - next->vm_start); 699287d97acSLinus Torvalds exporter = next; 7001da177e4SLinus Torvalds importer = vma; 701e86f15eeSAndrea Arcangeli VM_WARN_ON(expand != importer); 7021da177e4SLinus Torvalds } else if (end < vma->vm_end) { 7031da177e4SLinus Torvalds /* 7041da177e4SLinus Torvalds * vma shrinks, and !insert tells it's not 7051da177e4SLinus Torvalds * split_vma inserting another: so it must be 7061da177e4SLinus Torvalds * mprotect case 4 shifting the boundary down. 7071da177e4SLinus Torvalds */ 708f9d86a60SWei Yang adjust_next = -(vma->vm_end - end); 709287d97acSLinus Torvalds exporter = vma; 7101da177e4SLinus Torvalds importer = next; 711e86f15eeSAndrea Arcangeli VM_WARN_ON(expand != importer); 7121da177e4SLinus Torvalds } 7131da177e4SLinus Torvalds 7145beb4930SRik van Riel /* 7155beb4930SRik van Riel * Easily overlooked: when mprotect shifts the boundary, 7165beb4930SRik van Riel * make sure the expanding vma has anon_vma set if the 7175beb4930SRik van Riel * shrinking vma had, to cover any anon pages imported. 7185beb4930SRik van Riel */ 719287d97acSLinus Torvalds if (exporter && exporter->anon_vma && !importer->anon_vma) { 720c4ea95d7SDaniel Forrest int error; 721c4ea95d7SDaniel Forrest 722287d97acSLinus Torvalds importer->anon_vma = exporter->anon_vma; 723b800c91aSKonstantin Khlebnikov error = anon_vma_clone(importer, exporter); 7243fe89b3eSLeon Yu if (error) 725b800c91aSKonstantin Khlebnikov return error; 726b800c91aSKonstantin Khlebnikov } 7275beb4930SRik van Riel } 72837f9f559SKirill A. Shutemov 729c5d5546eSVernon Yang if (mas_preallocate(&mas, GFP_KERNEL)) 730d4af56c5SLiam R. Howlett return -ENOMEM; 731d4af56c5SLiam R. Howlett 732d4af56c5SLiam R. Howlett vma_adjust_trans_huge(orig_vma, start, end, adjust_next); 7331da177e4SLinus Torvalds if (file) { 7341da177e4SLinus Torvalds mapping = file->f_mapping; 7351da177e4SLinus Torvalds root = &mapping->i_mmap; 736cbc91f71SSrikar Dronamraju uprobe_munmap(vma, vma->vm_start, vma->vm_end); 737682968e0SSrikar Dronamraju 738682968e0SSrikar Dronamraju if (adjust_next) 73927ba0644SKirill A. Shutemov uprobe_munmap(next, next->vm_start, next->vm_end); 740682968e0SSrikar Dronamraju 74183cde9e8SDavidlohr Bueso i_mmap_lock_write(mapping); 742c154124fSLiam R. Howlett if (insert && insert->vm_file) { 7431da177e4SLinus Torvalds /* 7446b2dbba8SMichel Lespinasse * Put into interval tree now, so instantiated pages 7451da177e4SLinus Torvalds * are visible to arm/parisc __flush_dcache_page 7461da177e4SLinus Torvalds * throughout; but we cannot insert into address 7471da177e4SLinus Torvalds * space until vma start or end is updated. 7481da177e4SLinus Torvalds */ 749c154124fSLiam R. Howlett __vma_link_file(insert, insert->vm_file->f_mapping); 7501da177e4SLinus Torvalds } 7511da177e4SLinus Torvalds } 7521da177e4SLinus Torvalds 753012f1800SRik van Riel anon_vma = vma->anon_vma; 754bf181b9fSMichel Lespinasse if (!anon_vma && adjust_next) 755bf181b9fSMichel Lespinasse anon_vma = next->anon_vma; 756bf181b9fSMichel Lespinasse if (anon_vma) { 757e86f15eeSAndrea Arcangeli VM_WARN_ON(adjust_next && next->anon_vma && 758e86f15eeSAndrea Arcangeli anon_vma != next->anon_vma); 7594fc3f1d6SIngo Molnar anon_vma_lock_write(anon_vma); 760bf181b9fSMichel Lespinasse anon_vma_interval_tree_pre_update_vma(vma); 761bf181b9fSMichel Lespinasse if (adjust_next) 762bf181b9fSMichel Lespinasse anon_vma_interval_tree_pre_update_vma(next); 763bf181b9fSMichel Lespinasse } 764012f1800SRik van Riel 7650fc48a6eSWei Yang if (file) { 7661da177e4SLinus Torvalds flush_dcache_mmap_lock(mapping); 7676b2dbba8SMichel Lespinasse vma_interval_tree_remove(vma, root); 7681da177e4SLinus Torvalds if (adjust_next) 7696b2dbba8SMichel Lespinasse vma_interval_tree_remove(next, root); 7701da177e4SLinus Torvalds } 7711da177e4SLinus Torvalds 772d3737187SMichel Lespinasse if (start != vma->vm_start) { 7733b0e81a1SLiam R. Howlett if ((vma->vm_start < start) && 7743b0e81a1SLiam R. Howlett (!insert || (insert->vm_end != start))) { 775524e00b3SLiam R. Howlett vma_mas_szero(&mas, vma->vm_start, start); 7763b0e81a1SLiam R. Howlett VM_WARN_ON(insert && insert->vm_start > vma->vm_start); 7773b0e81a1SLiam R. Howlett } else { 778524e00b3SLiam R. Howlett vma_changed = true; 7793b0e81a1SLiam R. Howlett } 7801da177e4SLinus Torvalds vma->vm_start = start; 781d3737187SMichel Lespinasse } 782d3737187SMichel Lespinasse if (end != vma->vm_end) { 7833b0e81a1SLiam R. Howlett if (vma->vm_end > end) { 7843b0e81a1SLiam R. Howlett if (!insert || (insert->vm_start != end)) { 785524e00b3SLiam R. Howlett vma_mas_szero(&mas, end, vma->vm_end); 786763ecb03SLiam R. Howlett mas_reset(&mas); 7873b0e81a1SLiam R. Howlett VM_WARN_ON(insert && 7883b0e81a1SLiam R. Howlett insert->vm_end < vma->vm_end); 7893b0e81a1SLiam R. Howlett } 7903b0e81a1SLiam R. Howlett } else { 791524e00b3SLiam R. Howlett vma_changed = true; 7923b0e81a1SLiam R. Howlett } 7931da177e4SLinus Torvalds vma->vm_end = end; 794d3737187SMichel Lespinasse } 795d4af56c5SLiam R. Howlett 796524e00b3SLiam R. Howlett if (vma_changed) 797d4af56c5SLiam R. Howlett vma_mas_store(vma, &mas); 798d4af56c5SLiam R. Howlett 7991da177e4SLinus Torvalds vma->vm_pgoff = pgoff; 8001da177e4SLinus Torvalds if (adjust_next) { 801f9d86a60SWei Yang next->vm_start += adjust_next; 802f9d86a60SWei Yang next->vm_pgoff += adjust_next >> PAGE_SHIFT; 803d4af56c5SLiam R. Howlett vma_mas_store(next, &mas); 8041da177e4SLinus Torvalds } 8051da177e4SLinus Torvalds 8060fc48a6eSWei Yang if (file) { 8071da177e4SLinus Torvalds if (adjust_next) 8086b2dbba8SMichel Lespinasse vma_interval_tree_insert(next, root); 8096b2dbba8SMichel Lespinasse vma_interval_tree_insert(vma, root); 8101da177e4SLinus Torvalds flush_dcache_mmap_unlock(mapping); 8111da177e4SLinus Torvalds } 8121da177e4SLinus Torvalds 813763ecb03SLiam R. Howlett if (remove_next && file) { 8141da177e4SLinus Torvalds __remove_shared_vm_struct(next, file, mapping); 815d4af56c5SLiam R. Howlett if (remove_next == 2) 816d4af56c5SLiam R. Howlett __remove_shared_vm_struct(next_next, file, mapping); 8171da177e4SLinus Torvalds } else if (insert) { 8181da177e4SLinus Torvalds /* 8191da177e4SLinus Torvalds * split_vma has split insert from vma, and needs 8201da177e4SLinus Torvalds * us to insert it before dropping the locks 8211da177e4SLinus Torvalds * (it may either follow vma or precede it). 8221da177e4SLinus Torvalds */ 823763ecb03SLiam R. Howlett mas_reset(&mas); 824763ecb03SLiam R. Howlett vma_mas_store(insert, &mas); 825763ecb03SLiam R. Howlett mm->map_count++; 8261da177e4SLinus Torvalds } 8271da177e4SLinus Torvalds 828bf181b9fSMichel Lespinasse if (anon_vma) { 829bf181b9fSMichel Lespinasse anon_vma_interval_tree_post_update_vma(vma); 830bf181b9fSMichel Lespinasse if (adjust_next) 831bf181b9fSMichel Lespinasse anon_vma_interval_tree_post_update_vma(next); 83208b52706SKonstantin Khlebnikov anon_vma_unlock_write(anon_vma); 833bf181b9fSMichel Lespinasse } 8341da177e4SLinus Torvalds 8350fc48a6eSWei Yang if (file) { 836808fbdbeSWei Yang i_mmap_unlock_write(mapping); 8377b2d81d4SIngo Molnar uprobe_mmap(vma); 8382b144498SSrikar Dronamraju 8392b144498SSrikar Dronamraju if (adjust_next) 8407b2d81d4SIngo Molnar uprobe_mmap(next); 8412b144498SSrikar Dronamraju } 8422b144498SSrikar Dronamraju 8431da177e4SLinus Torvalds if (remove_next) { 844d4af56c5SLiam R. Howlett again: 845925d1c40SMatt Helsley if (file) { 846cbc91f71SSrikar Dronamraju uprobe_munmap(next, next->vm_start, next->vm_end); 8471da177e4SLinus Torvalds fput(file); 848925d1c40SMatt Helsley } 8495beb4930SRik van Riel if (next->anon_vma) 8505beb4930SRik van Riel anon_vma_merge(vma, next); 8511da177e4SLinus Torvalds mm->map_count--; 8523964acd0SOleg Nesterov mpol_put(vma_policy(next)); 853524e00b3SLiam R. Howlett if (remove_next != 2) 854524e00b3SLiam R. Howlett BUG_ON(vma->vm_end < next->vm_end); 8553928d4f5SLinus Torvalds vm_area_free(next); 856524e00b3SLiam R. Howlett 8571da177e4SLinus Torvalds /* 8581da177e4SLinus Torvalds * In mprotect's case 6 (see comments on vma_merge), 859763ecb03SLiam R. Howlett * we must remove next_next too. 8601da177e4SLinus Torvalds */ 861734537c9SKirill A. Shutemov if (remove_next == 2) { 862734537c9SKirill A. Shutemov remove_next = 1; 863763ecb03SLiam R. Howlett next = next_next; 8641da177e4SLinus Torvalds goto again; 865fb8c41e9SAndrea Arcangeli } 8661da177e4SLinus Torvalds } 8672b144498SSrikar Dronamraju if (insert && file) 8687b2d81d4SIngo Molnar uprobe_mmap(insert); 8691da177e4SLinus Torvalds 8703b0e81a1SLiam R. Howlett mas_destroy(&mas); 8711da177e4SLinus Torvalds validate_mm(mm); 872763ecb03SLiam R. Howlett 8735beb4930SRik van Riel return 0; 8741da177e4SLinus Torvalds } 8751da177e4SLinus Torvalds 8761da177e4SLinus Torvalds /* 8771da177e4SLinus Torvalds * If the vma has a ->close operation then the driver probably needs to release 8781da177e4SLinus Torvalds * per-vma resources, so we don't attempt to merge those. 8791da177e4SLinus Torvalds */ 8801da177e4SLinus Torvalds static inline int is_mergeable_vma(struct vm_area_struct *vma, 88119a809afSAndrea Arcangeli struct file *file, unsigned long vm_flags, 8829a10064fSColin Cross struct vm_userfaultfd_ctx vm_userfaultfd_ctx, 8835c26f6acSSuren Baghdasaryan struct anon_vma_name *anon_name) 8841da177e4SLinus Torvalds { 88534228d47SCyrill Gorcunov /* 88634228d47SCyrill Gorcunov * VM_SOFTDIRTY should not prevent from VMA merging, if we 88734228d47SCyrill Gorcunov * match the flags but dirty bit -- the caller should mark 88834228d47SCyrill Gorcunov * merged VMA as dirty. If dirty bit won't be excluded from 8898bb4e7a2SWei Yang * comparison, we increase pressure on the memory system forcing 89034228d47SCyrill Gorcunov * the kernel to generate new VMAs when old one could be 89134228d47SCyrill Gorcunov * extended instead. 89234228d47SCyrill Gorcunov */ 89334228d47SCyrill Gorcunov if ((vma->vm_flags ^ vm_flags) & ~VM_SOFTDIRTY) 8941da177e4SLinus Torvalds return 0; 8951da177e4SLinus Torvalds if (vma->vm_file != file) 8961da177e4SLinus Torvalds return 0; 8971da177e4SLinus Torvalds if (vma->vm_ops && vma->vm_ops->close) 8981da177e4SLinus Torvalds return 0; 89919a809afSAndrea Arcangeli if (!is_mergeable_vm_userfaultfd_ctx(vma, vm_userfaultfd_ctx)) 90019a809afSAndrea Arcangeli return 0; 9015c26f6acSSuren Baghdasaryan if (!anon_vma_name_eq(anon_vma_name(vma), anon_name)) 9029a10064fSColin Cross return 0; 9031da177e4SLinus Torvalds return 1; 9041da177e4SLinus Torvalds } 9051da177e4SLinus Torvalds 9061da177e4SLinus Torvalds static inline int is_mergeable_anon_vma(struct anon_vma *anon_vma1, 907965f55deSShaohua Li struct anon_vma *anon_vma2, 908965f55deSShaohua Li struct vm_area_struct *vma) 9091da177e4SLinus Torvalds { 910965f55deSShaohua Li /* 911965f55deSShaohua Li * The list_is_singular() test is to avoid merging VMA cloned from 912965f55deSShaohua Li * parents. This can improve scalability caused by anon_vma lock. 913965f55deSShaohua Li */ 914965f55deSShaohua Li if ((!anon_vma1 || !anon_vma2) && (!vma || 915965f55deSShaohua Li list_is_singular(&vma->anon_vma_chain))) 916965f55deSShaohua Li return 1; 917965f55deSShaohua Li return anon_vma1 == anon_vma2; 9181da177e4SLinus Torvalds } 9191da177e4SLinus Torvalds 9201da177e4SLinus Torvalds /* 9211da177e4SLinus Torvalds * Return true if we can merge this (vm_flags,anon_vma,file,vm_pgoff) 9221da177e4SLinus Torvalds * in front of (at a lower virtual address and file offset than) the vma. 9231da177e4SLinus Torvalds * 9241da177e4SLinus Torvalds * We cannot merge two vmas if they have differently assigned (non-NULL) 9251da177e4SLinus Torvalds * anon_vmas, nor if same anon_vma is assigned but offsets incompatible. 9261da177e4SLinus Torvalds * 9271da177e4SLinus Torvalds * We don't check here for the merged mmap wrapping around the end of pagecache 92845e55300SPeter Collingbourne * indices (16TB on ia32) because do_mmap() does not permit mmap's which 9291da177e4SLinus Torvalds * wrap, nor mmaps which cover the final page at index -1UL. 9301da177e4SLinus Torvalds */ 9311da177e4SLinus Torvalds static int 9321da177e4SLinus Torvalds can_vma_merge_before(struct vm_area_struct *vma, unsigned long vm_flags, 93319a809afSAndrea Arcangeli struct anon_vma *anon_vma, struct file *file, 93419a809afSAndrea Arcangeli pgoff_t vm_pgoff, 9359a10064fSColin Cross struct vm_userfaultfd_ctx vm_userfaultfd_ctx, 9365c26f6acSSuren Baghdasaryan struct anon_vma_name *anon_name) 9371da177e4SLinus Torvalds { 9389a10064fSColin Cross if (is_mergeable_vma(vma, file, vm_flags, vm_userfaultfd_ctx, anon_name) && 939965f55deSShaohua Li is_mergeable_anon_vma(anon_vma, vma->anon_vma, vma)) { 9401da177e4SLinus Torvalds if (vma->vm_pgoff == vm_pgoff) 9411da177e4SLinus Torvalds return 1; 9421da177e4SLinus Torvalds } 9431da177e4SLinus Torvalds return 0; 9441da177e4SLinus Torvalds } 9451da177e4SLinus Torvalds 9461da177e4SLinus Torvalds /* 9471da177e4SLinus Torvalds * Return true if we can merge this (vm_flags,anon_vma,file,vm_pgoff) 9481da177e4SLinus Torvalds * beyond (at a higher virtual address and file offset than) the vma. 9491da177e4SLinus Torvalds * 9501da177e4SLinus Torvalds * We cannot merge two vmas if they have differently assigned (non-NULL) 9511da177e4SLinus Torvalds * anon_vmas, nor if same anon_vma is assigned but offsets incompatible. 9521da177e4SLinus Torvalds */ 9531da177e4SLinus Torvalds static int 9541da177e4SLinus Torvalds can_vma_merge_after(struct vm_area_struct *vma, unsigned long vm_flags, 95519a809afSAndrea Arcangeli struct anon_vma *anon_vma, struct file *file, 95619a809afSAndrea Arcangeli pgoff_t vm_pgoff, 9579a10064fSColin Cross struct vm_userfaultfd_ctx vm_userfaultfd_ctx, 9585c26f6acSSuren Baghdasaryan struct anon_vma_name *anon_name) 9591da177e4SLinus Torvalds { 9609a10064fSColin Cross if (is_mergeable_vma(vma, file, vm_flags, vm_userfaultfd_ctx, anon_name) && 961965f55deSShaohua Li is_mergeable_anon_vma(anon_vma, vma->anon_vma, vma)) { 9621da177e4SLinus Torvalds pgoff_t vm_pglen; 963d6e93217SLibin vm_pglen = vma_pages(vma); 9641da177e4SLinus Torvalds if (vma->vm_pgoff + vm_pglen == vm_pgoff) 9651da177e4SLinus Torvalds return 1; 9661da177e4SLinus Torvalds } 9671da177e4SLinus Torvalds return 0; 9681da177e4SLinus Torvalds } 9691da177e4SLinus Torvalds 9701da177e4SLinus Torvalds /* 9719a10064fSColin Cross * Given a mapping request (addr,end,vm_flags,file,pgoff,anon_name), 9729a10064fSColin Cross * figure out whether that can be merged with its predecessor or its 9739a10064fSColin Cross * successor. Or both (it neatly fills a hole). 9741da177e4SLinus Torvalds * 9751da177e4SLinus Torvalds * In most cases - when called for mmap, brk or mremap - [addr,end) is 9761da177e4SLinus Torvalds * certain not to be mapped by the time vma_merge is called; but when 9771da177e4SLinus Torvalds * called for mprotect, it is certain to be already mapped (either at 9781da177e4SLinus Torvalds * an offset within prev, or at the start of next), and the flags of 9791da177e4SLinus Torvalds * this area are about to be changed to vm_flags - and the no-change 9801da177e4SLinus Torvalds * case has already been eliminated. 9811da177e4SLinus Torvalds * 9821da177e4SLinus Torvalds * The following mprotect cases have to be considered, where AAAA is 9831da177e4SLinus Torvalds * the area passed down from mprotect_fixup, never extending beyond one 9841da177e4SLinus Torvalds * vma, PPPPPP is the prev vma specified, and NNNNNN the next vma after: 9851da177e4SLinus Torvalds * 9865d42ab29SWei Yang * AAAA AAAA AAAA 9875d42ab29SWei Yang * PPPPPPNNNNNN PPPPPPNNNNNN PPPPPPNNNNNN 9885d42ab29SWei Yang * cannot merge might become might become 9895d42ab29SWei Yang * PPNNNNNNNNNN PPPPPPPPPPNN 9905d42ab29SWei Yang * mmap, brk or case 4 below case 5 below 9915d42ab29SWei Yang * mremap move: 9925d42ab29SWei Yang * AAAA AAAA 9935d42ab29SWei Yang * PPPP NNNN PPPPNNNNXXXX 9945d42ab29SWei Yang * might become might become 9955d42ab29SWei Yang * PPPPPPPPPPPP 1 or PPPPPPPPPPPP 6 or 9965d42ab29SWei Yang * PPPPPPPPNNNN 2 or PPPPPPPPXXXX 7 or 9975d42ab29SWei Yang * PPPPNNNNNNNN 3 PPPPXXXXXXXX 8 9981da177e4SLinus Torvalds * 9998bb4e7a2SWei Yang * It is important for case 8 that the vma NNNN overlapping the 1000e86f15eeSAndrea Arcangeli * region AAAA is never going to extended over XXXX. Instead XXXX must 1001e86f15eeSAndrea Arcangeli * be extended in region AAAA and NNNN must be removed. This way in 1002e86f15eeSAndrea Arcangeli * all cases where vma_merge succeeds, the moment vma_adjust drops the 1003e86f15eeSAndrea Arcangeli * rmap_locks, the properties of the merged vma will be already 1004e86f15eeSAndrea Arcangeli * correct for the whole merged range. Some of those properties like 1005e86f15eeSAndrea Arcangeli * vm_page_prot/vm_flags may be accessed by rmap_walks and they must 1006e86f15eeSAndrea Arcangeli * be correct for the whole merged range immediately after the 1007e86f15eeSAndrea Arcangeli * rmap_locks are released. Otherwise if XXXX would be removed and 1008e86f15eeSAndrea Arcangeli * NNNN would be extended over the XXXX range, remove_migration_ptes 1009e86f15eeSAndrea Arcangeli * or other rmap walkers (if working on addresses beyond the "end" 1010e86f15eeSAndrea Arcangeli * parameter) may establish ptes with the wrong permissions of NNNN 1011e86f15eeSAndrea Arcangeli * instead of the right permissions of XXXX. 10121da177e4SLinus Torvalds */ 10131da177e4SLinus Torvalds struct vm_area_struct *vma_merge(struct mm_struct *mm, 10141da177e4SLinus Torvalds struct vm_area_struct *prev, unsigned long addr, 10151da177e4SLinus Torvalds unsigned long end, unsigned long vm_flags, 10161da177e4SLinus Torvalds struct anon_vma *anon_vma, struct file *file, 101719a809afSAndrea Arcangeli pgoff_t pgoff, struct mempolicy *policy, 10189a10064fSColin Cross struct vm_userfaultfd_ctx vm_userfaultfd_ctx, 10195c26f6acSSuren Baghdasaryan struct anon_vma_name *anon_name) 10201da177e4SLinus Torvalds { 10211da177e4SLinus Torvalds pgoff_t pglen = (end - addr) >> PAGE_SHIFT; 1022eef19944SJakub Matěna struct vm_area_struct *mid, *next, *res; 1023eef19944SJakub Matěna int err = -1; 1024eef19944SJakub Matěna bool merge_prev = false; 1025eef19944SJakub Matěna bool merge_next = false; 10261da177e4SLinus Torvalds 10271da177e4SLinus Torvalds /* 10281da177e4SLinus Torvalds * We later require that vma->vm_flags == vm_flags, 10291da177e4SLinus Torvalds * so this tests vma->vm_flags & VM_SPECIAL, too. 10301da177e4SLinus Torvalds */ 10311da177e4SLinus Torvalds if (vm_flags & VM_SPECIAL) 10321da177e4SLinus Torvalds return NULL; 10331da177e4SLinus Torvalds 1034763ecb03SLiam R. Howlett next = find_vma(mm, prev ? prev->vm_end : 0); 1035eef19944SJakub Matěna mid = next; 1036eef19944SJakub Matěna if (next && next->vm_end == end) /* cases 6, 7, 8 */ 1037763ecb03SLiam R. Howlett next = find_vma(mm, next->vm_end); 10381da177e4SLinus Torvalds 1039e86f15eeSAndrea Arcangeli /* verify some invariant that must be enforced by the caller */ 1040e86f15eeSAndrea Arcangeli VM_WARN_ON(prev && addr <= prev->vm_start); 1041eef19944SJakub Matěna VM_WARN_ON(mid && end > mid->vm_end); 1042e86f15eeSAndrea Arcangeli VM_WARN_ON(addr >= end); 1043e86f15eeSAndrea Arcangeli 1044eef19944SJakub Matěna /* Can we merge the predecessor? */ 10451da177e4SLinus Torvalds if (prev && prev->vm_end == addr && 10461da177e4SLinus Torvalds mpol_equal(vma_policy(prev), policy) && 10471da177e4SLinus Torvalds can_vma_merge_after(prev, vm_flags, 104819a809afSAndrea Arcangeli anon_vma, file, pgoff, 10499a10064fSColin Cross vm_userfaultfd_ctx, anon_name)) { 1050eef19944SJakub Matěna merge_prev = true; 10511da177e4SLinus Torvalds } 1052eef19944SJakub Matěna /* Can we merge the successor? */ 10531da177e4SLinus Torvalds if (next && end == next->vm_start && 10541da177e4SLinus Torvalds mpol_equal(policy, vma_policy(next)) && 10551da177e4SLinus Torvalds can_vma_merge_before(next, vm_flags, 105619a809afSAndrea Arcangeli anon_vma, file, pgoff+pglen, 10579a10064fSColin Cross vm_userfaultfd_ctx, anon_name)) { 1058eef19944SJakub Matěna merge_next = true; 1059eef19944SJakub Matěna } 1060eef19944SJakub Matěna /* Can we merge both the predecessor and the successor? */ 1061eef19944SJakub Matěna if (merge_prev && merge_next && 1062eef19944SJakub Matěna is_mergeable_anon_vma(prev->anon_vma, 1063eef19944SJakub Matěna next->anon_vma, NULL)) { /* cases 1, 6 */ 1064eef19944SJakub Matěna err = __vma_adjust(prev, prev->vm_start, 1065eef19944SJakub Matěna next->vm_end, prev->vm_pgoff, NULL, 1066eef19944SJakub Matěna prev); 1067eef19944SJakub Matěna res = prev; 1068eef19944SJakub Matěna } else if (merge_prev) { /* cases 2, 5, 7 */ 1069eef19944SJakub Matěna err = __vma_adjust(prev, prev->vm_start, 1070eef19944SJakub Matěna end, prev->vm_pgoff, NULL, prev); 1071eef19944SJakub Matěna res = prev; 1072eef19944SJakub Matěna } else if (merge_next) { 10731da177e4SLinus Torvalds if (prev && addr < prev->vm_end) /* case 4 */ 1074e86f15eeSAndrea Arcangeli err = __vma_adjust(prev, prev->vm_start, 1075e86f15eeSAndrea Arcangeli addr, prev->vm_pgoff, NULL, next); 1076eef19944SJakub Matěna else /* cases 3, 8 */ 1077eef19944SJakub Matěna err = __vma_adjust(mid, addr, next->vm_end, 1078e86f15eeSAndrea Arcangeli next->vm_pgoff - pglen, NULL, next); 1079eef19944SJakub Matěna res = next; 10801da177e4SLinus Torvalds } 10811da177e4SLinus Torvalds 1082eef19944SJakub Matěna /* 1083eef19944SJakub Matěna * Cannot merge with predecessor or successor or error in __vma_adjust? 1084eef19944SJakub Matěna */ 1085eef19944SJakub Matěna if (err) 10861da177e4SLinus Torvalds return NULL; 1087eef19944SJakub Matěna khugepaged_enter_vma(res, vm_flags); 1088eef19944SJakub Matěna return res; 10891da177e4SLinus Torvalds } 10901da177e4SLinus Torvalds 1091f2ebfe43SLiam R. Howlett struct vm_area_struct *vmi_vma_merge(struct vma_iterator *vmi, 1092f2ebfe43SLiam R. Howlett struct mm_struct *mm, 1093f2ebfe43SLiam R. Howlett struct vm_area_struct *prev, unsigned long addr, 1094f2ebfe43SLiam R. Howlett unsigned long end, unsigned long vm_flags, 1095f2ebfe43SLiam R. Howlett struct anon_vma *anon_vma, struct file *file, 1096f2ebfe43SLiam R. Howlett pgoff_t pgoff, struct mempolicy *policy, 1097f2ebfe43SLiam R. Howlett struct vm_userfaultfd_ctx vm_userfaultfd_ctx, 1098f2ebfe43SLiam R. Howlett struct anon_vma_name *anon_name) 1099f2ebfe43SLiam R. Howlett { 1100f2ebfe43SLiam R. Howlett struct vm_area_struct *tmp; 1101f2ebfe43SLiam R. Howlett 1102f2ebfe43SLiam R. Howlett tmp = vma_merge(mm, prev, addr, end, vm_flags, anon_vma, file, pgoff, 1103f2ebfe43SLiam R. Howlett policy, vm_userfaultfd_ctx, anon_name); 1104f2ebfe43SLiam R. Howlett if (tmp) 1105f2ebfe43SLiam R. Howlett vma_iter_set(vmi, end); 1106f2ebfe43SLiam R. Howlett 1107f2ebfe43SLiam R. Howlett return tmp; 1108f2ebfe43SLiam R. Howlett } 1109f2ebfe43SLiam R. Howlett 11101da177e4SLinus Torvalds /* 1111b4f315b4SEthon Paul * Rough compatibility check to quickly see if it's even worth looking 1112d0e9fe17SLinus Torvalds * at sharing an anon_vma. 1113d0e9fe17SLinus Torvalds * 1114d0e9fe17SLinus Torvalds * They need to have the same vm_file, and the flags can only differ 1115d0e9fe17SLinus Torvalds * in things that mprotect may change. 1116d0e9fe17SLinus Torvalds * 1117d0e9fe17SLinus Torvalds * NOTE! The fact that we share an anon_vma doesn't _have_ to mean that 1118d0e9fe17SLinus Torvalds * we can merge the two vma's. For example, we refuse to merge a vma if 1119d0e9fe17SLinus Torvalds * there is a vm_ops->close() function, because that indicates that the 1120d0e9fe17SLinus Torvalds * driver is doing some kind of reference counting. But that doesn't 1121d0e9fe17SLinus Torvalds * really matter for the anon_vma sharing case. 1122d0e9fe17SLinus Torvalds */ 1123d0e9fe17SLinus Torvalds static int anon_vma_compatible(struct vm_area_struct *a, struct vm_area_struct *b) 1124d0e9fe17SLinus Torvalds { 1125d0e9fe17SLinus Torvalds return a->vm_end == b->vm_start && 1126d0e9fe17SLinus Torvalds mpol_equal(vma_policy(a), vma_policy(b)) && 1127d0e9fe17SLinus Torvalds a->vm_file == b->vm_file && 11286cb4d9a2SAnshuman Khandual !((a->vm_flags ^ b->vm_flags) & ~(VM_ACCESS_FLAGS | VM_SOFTDIRTY)) && 1129d0e9fe17SLinus Torvalds b->vm_pgoff == a->vm_pgoff + ((b->vm_start - a->vm_start) >> PAGE_SHIFT); 1130d0e9fe17SLinus Torvalds } 1131d0e9fe17SLinus Torvalds 1132d0e9fe17SLinus Torvalds /* 1133d0e9fe17SLinus Torvalds * Do some basic sanity checking to see if we can re-use the anon_vma 1134d0e9fe17SLinus Torvalds * from 'old'. The 'a'/'b' vma's are in VM order - one of them will be 1135d0e9fe17SLinus Torvalds * the same as 'old', the other will be the new one that is trying 1136d0e9fe17SLinus Torvalds * to share the anon_vma. 1137d0e9fe17SLinus Torvalds * 11385b449489SFlorian Rommel * NOTE! This runs with mmap_lock held for reading, so it is possible that 1139d0e9fe17SLinus Torvalds * the anon_vma of 'old' is concurrently in the process of being set up 1140d0e9fe17SLinus Torvalds * by another page fault trying to merge _that_. But that's ok: if it 1141d0e9fe17SLinus Torvalds * is being set up, that automatically means that it will be a singleton 1142d0e9fe17SLinus Torvalds * acceptable for merging, so we can do all of this optimistically. But 11434db0c3c2SJason Low * we do that READ_ONCE() to make sure that we never re-load the pointer. 1144d0e9fe17SLinus Torvalds * 1145d0e9fe17SLinus Torvalds * IOW: that the "list_is_singular()" test on the anon_vma_chain only 1146d0e9fe17SLinus Torvalds * matters for the 'stable anon_vma' case (ie the thing we want to avoid 1147d0e9fe17SLinus Torvalds * is to return an anon_vma that is "complex" due to having gone through 1148d0e9fe17SLinus Torvalds * a fork). 1149d0e9fe17SLinus Torvalds * 1150d0e9fe17SLinus Torvalds * We also make sure that the two vma's are compatible (adjacent, 1151d0e9fe17SLinus Torvalds * and with the same memory policies). That's all stable, even with just 11525b449489SFlorian Rommel * a read lock on the mmap_lock. 1153d0e9fe17SLinus Torvalds */ 1154d0e9fe17SLinus Torvalds static struct anon_vma *reusable_anon_vma(struct vm_area_struct *old, struct vm_area_struct *a, struct vm_area_struct *b) 1155d0e9fe17SLinus Torvalds { 1156d0e9fe17SLinus Torvalds if (anon_vma_compatible(a, b)) { 11574db0c3c2SJason Low struct anon_vma *anon_vma = READ_ONCE(old->anon_vma); 1158d0e9fe17SLinus Torvalds 1159d0e9fe17SLinus Torvalds if (anon_vma && list_is_singular(&old->anon_vma_chain)) 1160d0e9fe17SLinus Torvalds return anon_vma; 1161d0e9fe17SLinus Torvalds } 1162d0e9fe17SLinus Torvalds return NULL; 1163d0e9fe17SLinus Torvalds } 1164d0e9fe17SLinus Torvalds 1165d0e9fe17SLinus Torvalds /* 11661da177e4SLinus Torvalds * find_mergeable_anon_vma is used by anon_vma_prepare, to check 11671da177e4SLinus Torvalds * neighbouring vmas for a suitable anon_vma, before it goes off 11681da177e4SLinus Torvalds * to allocate a new anon_vma. It checks because a repetitive 11691da177e4SLinus Torvalds * sequence of mprotects and faults may otherwise lead to distinct 11701da177e4SLinus Torvalds * anon_vmas being allocated, preventing vma merge in subsequent 11711da177e4SLinus Torvalds * mprotect. 11721da177e4SLinus Torvalds */ 11731da177e4SLinus Torvalds struct anon_vma *find_mergeable_anon_vma(struct vm_area_struct *vma) 11741da177e4SLinus Torvalds { 1175763ecb03SLiam R. Howlett MA_STATE(mas, &vma->vm_mm->mm_mt, vma->vm_end, vma->vm_end); 1176a67c8caaSMiaohe Lin struct anon_vma *anon_vma = NULL; 1177763ecb03SLiam R. Howlett struct vm_area_struct *prev, *next; 11781da177e4SLinus Torvalds 1179a67c8caaSMiaohe Lin /* Try next first. */ 1180763ecb03SLiam R. Howlett next = mas_walk(&mas); 1181763ecb03SLiam R. Howlett if (next) { 1182763ecb03SLiam R. Howlett anon_vma = reusable_anon_vma(next, vma, next); 1183d0e9fe17SLinus Torvalds if (anon_vma) 1184d0e9fe17SLinus Torvalds return anon_vma; 1185a67c8caaSMiaohe Lin } 11861da177e4SLinus Torvalds 1187763ecb03SLiam R. Howlett prev = mas_prev(&mas, 0); 1188763ecb03SLiam R. Howlett VM_BUG_ON_VMA(prev != vma, vma); 1189763ecb03SLiam R. Howlett prev = mas_prev(&mas, 0); 1190a67c8caaSMiaohe Lin /* Try prev next. */ 1191763ecb03SLiam R. Howlett if (prev) 1192763ecb03SLiam R. Howlett anon_vma = reusable_anon_vma(prev, prev, vma); 1193a67c8caaSMiaohe Lin 11941da177e4SLinus Torvalds /* 1195a67c8caaSMiaohe Lin * We might reach here with anon_vma == NULL if we can't find 1196a67c8caaSMiaohe Lin * any reusable anon_vma. 11971da177e4SLinus Torvalds * There's no absolute need to look only at touching neighbours: 11981da177e4SLinus Torvalds * we could search further afield for "compatible" anon_vmas. 11991da177e4SLinus Torvalds * But it would probably just be a waste of time searching, 12001da177e4SLinus Torvalds * or lead to too many vmas hanging off the same anon_vma. 12011da177e4SLinus Torvalds * We're trying to allow mprotect remerging later on, 12021da177e4SLinus Torvalds * not trying to minimize memory used for anon_vmas. 12031da177e4SLinus Torvalds */ 1204a67c8caaSMiaohe Lin return anon_vma; 12051da177e4SLinus Torvalds } 12061da177e4SLinus Torvalds 12071da177e4SLinus Torvalds /* 120840401530SAl Viro * If a hint addr is less than mmap_min_addr change hint to be as 120940401530SAl Viro * low as possible but still greater than mmap_min_addr 121040401530SAl Viro */ 121140401530SAl Viro static inline unsigned long round_hint_to_min(unsigned long hint) 121240401530SAl Viro { 121340401530SAl Viro hint &= PAGE_MASK; 121440401530SAl Viro if (((void *)hint != NULL) && 121540401530SAl Viro (hint < mmap_min_addr)) 121640401530SAl Viro return PAGE_ALIGN(mmap_min_addr); 121740401530SAl Viro return hint; 121840401530SAl Viro } 121940401530SAl Viro 12206aeb2542SMike Rapoport int mlock_future_check(struct mm_struct *mm, unsigned long flags, 1221363ee17fSDavidlohr Bueso unsigned long len) 1222363ee17fSDavidlohr Bueso { 1223363ee17fSDavidlohr Bueso unsigned long locked, lock_limit; 1224363ee17fSDavidlohr Bueso 1225363ee17fSDavidlohr Bueso /* mlock MCL_FUTURE? */ 1226363ee17fSDavidlohr Bueso if (flags & VM_LOCKED) { 1227363ee17fSDavidlohr Bueso locked = len >> PAGE_SHIFT; 1228363ee17fSDavidlohr Bueso locked += mm->locked_vm; 1229363ee17fSDavidlohr Bueso lock_limit = rlimit(RLIMIT_MEMLOCK); 1230363ee17fSDavidlohr Bueso lock_limit >>= PAGE_SHIFT; 1231363ee17fSDavidlohr Bueso if (locked > lock_limit && !capable(CAP_IPC_LOCK)) 1232363ee17fSDavidlohr Bueso return -EAGAIN; 1233363ee17fSDavidlohr Bueso } 1234363ee17fSDavidlohr Bueso return 0; 1235363ee17fSDavidlohr Bueso } 1236363ee17fSDavidlohr Bueso 1237be83bbf8SLinus Torvalds static inline u64 file_mmap_size_max(struct file *file, struct inode *inode) 1238be83bbf8SLinus Torvalds { 1239be83bbf8SLinus Torvalds if (S_ISREG(inode->i_mode)) 1240423913adSLinus Torvalds return MAX_LFS_FILESIZE; 1241be83bbf8SLinus Torvalds 1242be83bbf8SLinus Torvalds if (S_ISBLK(inode->i_mode)) 1243be83bbf8SLinus Torvalds return MAX_LFS_FILESIZE; 1244be83bbf8SLinus Torvalds 124576f34950SIvan Khoronzhuk if (S_ISSOCK(inode->i_mode)) 124676f34950SIvan Khoronzhuk return MAX_LFS_FILESIZE; 124776f34950SIvan Khoronzhuk 1248be83bbf8SLinus Torvalds /* Special "we do even unsigned file positions" case */ 1249be83bbf8SLinus Torvalds if (file->f_mode & FMODE_UNSIGNED_OFFSET) 1250be83bbf8SLinus Torvalds return 0; 1251be83bbf8SLinus Torvalds 1252be83bbf8SLinus Torvalds /* Yes, random drivers might want more. But I'm tired of buggy drivers */ 1253be83bbf8SLinus Torvalds return ULONG_MAX; 1254be83bbf8SLinus Torvalds } 1255be83bbf8SLinus Torvalds 1256be83bbf8SLinus Torvalds static inline bool file_mmap_ok(struct file *file, struct inode *inode, 1257be83bbf8SLinus Torvalds unsigned long pgoff, unsigned long len) 1258be83bbf8SLinus Torvalds { 1259be83bbf8SLinus Torvalds u64 maxsize = file_mmap_size_max(file, inode); 1260be83bbf8SLinus Torvalds 1261be83bbf8SLinus Torvalds if (maxsize && len > maxsize) 1262be83bbf8SLinus Torvalds return false; 1263be83bbf8SLinus Torvalds maxsize -= len; 1264be83bbf8SLinus Torvalds if (pgoff > maxsize >> PAGE_SHIFT) 1265be83bbf8SLinus Torvalds return false; 1266be83bbf8SLinus Torvalds return true; 1267be83bbf8SLinus Torvalds } 1268be83bbf8SLinus Torvalds 126940401530SAl Viro /* 12703e4e28c5SMichel Lespinasse * The caller must write-lock current->mm->mmap_lock. 12711da177e4SLinus Torvalds */ 12721fcfd8dbSOleg Nesterov unsigned long do_mmap(struct file *file, unsigned long addr, 12731da177e4SLinus Torvalds unsigned long len, unsigned long prot, 127445e55300SPeter Collingbourne unsigned long flags, unsigned long pgoff, 127545e55300SPeter Collingbourne unsigned long *populate, struct list_head *uf) 12761da177e4SLinus Torvalds { 12771da177e4SLinus Torvalds struct mm_struct *mm = current->mm; 127845e55300SPeter Collingbourne vm_flags_t vm_flags; 127962b5f7d0SDave Hansen int pkey = 0; 12801da177e4SLinus Torvalds 1281524e00b3SLiam R. Howlett validate_mm(mm); 128241badc15SMichel Lespinasse *populate = 0; 1283bebeb3d6SMichel Lespinasse 1284e37609bbSPiotr Kwapulinski if (!len) 1285e37609bbSPiotr Kwapulinski return -EINVAL; 1286e37609bbSPiotr Kwapulinski 12871da177e4SLinus Torvalds /* 12881da177e4SLinus Torvalds * Does the application expect PROT_READ to imply PROT_EXEC? 12891da177e4SLinus Torvalds * 12901da177e4SLinus Torvalds * (the exception is when the underlying filesystem is noexec 12911da177e4SLinus Torvalds * mounted, in which case we dont add PROT_EXEC.) 12921da177e4SLinus Torvalds */ 12931da177e4SLinus Torvalds if ((prot & PROT_READ) && (current->personality & READ_IMPLIES_EXEC)) 129490f8572bSEric W. Biederman if (!(file && path_noexec(&file->f_path))) 12951da177e4SLinus Torvalds prot |= PROT_EXEC; 12961da177e4SLinus Torvalds 1297a4ff8e86SMichal Hocko /* force arch specific MAP_FIXED handling in get_unmapped_area */ 1298a4ff8e86SMichal Hocko if (flags & MAP_FIXED_NOREPLACE) 1299a4ff8e86SMichal Hocko flags |= MAP_FIXED; 1300a4ff8e86SMichal Hocko 13017cd94146SEric Paris if (!(flags & MAP_FIXED)) 13027cd94146SEric Paris addr = round_hint_to_min(addr); 13037cd94146SEric Paris 13041da177e4SLinus Torvalds /* Careful about overflows.. */ 13051da177e4SLinus Torvalds len = PAGE_ALIGN(len); 13069206de95SAl Viro if (!len) 13071da177e4SLinus Torvalds return -ENOMEM; 13081da177e4SLinus Torvalds 13091da177e4SLinus Torvalds /* offset overflow? */ 13101da177e4SLinus Torvalds if ((pgoff + (len >> PAGE_SHIFT)) < pgoff) 13111da177e4SLinus Torvalds return -EOVERFLOW; 13121da177e4SLinus Torvalds 13131da177e4SLinus Torvalds /* Too many mappings? */ 13141da177e4SLinus Torvalds if (mm->map_count > sysctl_max_map_count) 13151da177e4SLinus Torvalds return -ENOMEM; 13161da177e4SLinus Torvalds 13171da177e4SLinus Torvalds /* Obtain the address to map to. we verify (or select) it and ensure 13181da177e4SLinus Torvalds * that it represents a valid section of the address space. 13191da177e4SLinus Torvalds */ 13201da177e4SLinus Torvalds addr = get_unmapped_area(file, addr, len, pgoff, flags); 1321ff68dac6SGaowei Pu if (IS_ERR_VALUE(addr)) 13221da177e4SLinus Torvalds return addr; 13231da177e4SLinus Torvalds 1324a4ff8e86SMichal Hocko if (flags & MAP_FIXED_NOREPLACE) { 132535e43c5fSLiam Howlett if (find_vma_intersection(mm, addr, addr + len)) 1326a4ff8e86SMichal Hocko return -EEXIST; 1327a4ff8e86SMichal Hocko } 1328a4ff8e86SMichal Hocko 132962b5f7d0SDave Hansen if (prot == PROT_EXEC) { 133062b5f7d0SDave Hansen pkey = execute_only_pkey(mm); 133162b5f7d0SDave Hansen if (pkey < 0) 133262b5f7d0SDave Hansen pkey = 0; 133362b5f7d0SDave Hansen } 133462b5f7d0SDave Hansen 13351da177e4SLinus Torvalds /* Do simple checking here so the lower-level routines won't have 13361da177e4SLinus Torvalds * to. we assume access permissions have been handled by the open 13371da177e4SLinus Torvalds * of the memory object, so we don't do any here. 13381da177e4SLinus Torvalds */ 133945e55300SPeter Collingbourne vm_flags = calc_vm_prot_bits(prot, pkey) | calc_vm_flag_bits(flags) | 13401da177e4SLinus Torvalds mm->def_flags | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC; 13411da177e4SLinus Torvalds 1342cdf7b341SHuang Shijie if (flags & MAP_LOCKED) 13431da177e4SLinus Torvalds if (!can_do_mlock()) 13441da177e4SLinus Torvalds return -EPERM; 1345ba470de4SRik van Riel 1346363ee17fSDavidlohr Bueso if (mlock_future_check(mm, vm_flags, len)) 13471da177e4SLinus Torvalds return -EAGAIN; 13481da177e4SLinus Torvalds 13491da177e4SLinus Torvalds if (file) { 1350077bf22bSOleg Nesterov struct inode *inode = file_inode(file); 13511c972597SDan Williams unsigned long flags_mask; 13521c972597SDan Williams 1353be83bbf8SLinus Torvalds if (!file_mmap_ok(file, inode, pgoff, len)) 1354be83bbf8SLinus Torvalds return -EOVERFLOW; 1355be83bbf8SLinus Torvalds 13561c972597SDan Williams flags_mask = LEGACY_MAP_MASK | file->f_op->mmap_supported_flags; 1357077bf22bSOleg Nesterov 13581da177e4SLinus Torvalds switch (flags & MAP_TYPE) { 13591da177e4SLinus Torvalds case MAP_SHARED: 13601c972597SDan Williams /* 13611c972597SDan Williams * Force use of MAP_SHARED_VALIDATE with non-legacy 13621c972597SDan Williams * flags. E.g. MAP_SYNC is dangerous to use with 13631c972597SDan Williams * MAP_SHARED as you don't know which consistency model 13641c972597SDan Williams * you will get. We silently ignore unsupported flags 13651c972597SDan Williams * with MAP_SHARED to preserve backward compatibility. 13661c972597SDan Williams */ 13671c972597SDan Williams flags &= LEGACY_MAP_MASK; 1368e4a9bc58SJoe Perches fallthrough; 13691c972597SDan Williams case MAP_SHARED_VALIDATE: 13701c972597SDan Williams if (flags & ~flags_mask) 13711c972597SDan Williams return -EOPNOTSUPP; 1372dc617f29SDarrick J. Wong if (prot & PROT_WRITE) { 1373dc617f29SDarrick J. Wong if (!(file->f_mode & FMODE_WRITE)) 13741da177e4SLinus Torvalds return -EACCES; 1375dc617f29SDarrick J. Wong if (IS_SWAPFILE(file->f_mapping->host)) 1376dc617f29SDarrick J. Wong return -ETXTBSY; 1377dc617f29SDarrick J. Wong } 13781da177e4SLinus Torvalds 13791da177e4SLinus Torvalds /* 13801da177e4SLinus Torvalds * Make sure we don't allow writing to an append-only 13811da177e4SLinus Torvalds * file.. 13821da177e4SLinus Torvalds */ 13831da177e4SLinus Torvalds if (IS_APPEND(inode) && (file->f_mode & FMODE_WRITE)) 13841da177e4SLinus Torvalds return -EACCES; 13851da177e4SLinus Torvalds 13861da177e4SLinus Torvalds vm_flags |= VM_SHARED | VM_MAYSHARE; 13871da177e4SLinus Torvalds if (!(file->f_mode & FMODE_WRITE)) 13881da177e4SLinus Torvalds vm_flags &= ~(VM_MAYWRITE | VM_SHARED); 1389e4a9bc58SJoe Perches fallthrough; 13901da177e4SLinus Torvalds case MAP_PRIVATE: 13911da177e4SLinus Torvalds if (!(file->f_mode & FMODE_READ)) 13921da177e4SLinus Torvalds return -EACCES; 139390f8572bSEric W. Biederman if (path_noexec(&file->f_path)) { 139480c5606cSLinus Torvalds if (vm_flags & VM_EXEC) 139580c5606cSLinus Torvalds return -EPERM; 139680c5606cSLinus Torvalds vm_flags &= ~VM_MAYEXEC; 139780c5606cSLinus Torvalds } 139880c5606cSLinus Torvalds 139972c2d531SAl Viro if (!file->f_op->mmap) 140080c5606cSLinus Torvalds return -ENODEV; 1401b2c56e4fSOleg Nesterov if (vm_flags & (VM_GROWSDOWN|VM_GROWSUP)) 1402b2c56e4fSOleg Nesterov return -EINVAL; 14031da177e4SLinus Torvalds break; 14041da177e4SLinus Torvalds 14051da177e4SLinus Torvalds default: 14061da177e4SLinus Torvalds return -EINVAL; 14071da177e4SLinus Torvalds } 14081da177e4SLinus Torvalds } else { 14091da177e4SLinus Torvalds switch (flags & MAP_TYPE) { 14101da177e4SLinus Torvalds case MAP_SHARED: 1411b2c56e4fSOleg Nesterov if (vm_flags & (VM_GROWSDOWN|VM_GROWSUP)) 1412b2c56e4fSOleg Nesterov return -EINVAL; 1413ce363942STejun Heo /* 1414ce363942STejun Heo * Ignore pgoff. 1415ce363942STejun Heo */ 1416ce363942STejun Heo pgoff = 0; 14171da177e4SLinus Torvalds vm_flags |= VM_SHARED | VM_MAYSHARE; 14181da177e4SLinus Torvalds break; 14191da177e4SLinus Torvalds case MAP_PRIVATE: 14201da177e4SLinus Torvalds /* 14211da177e4SLinus Torvalds * Set pgoff according to addr for anon_vma. 14221da177e4SLinus Torvalds */ 14231da177e4SLinus Torvalds pgoff = addr >> PAGE_SHIFT; 14241da177e4SLinus Torvalds break; 14251da177e4SLinus Torvalds default: 14261da177e4SLinus Torvalds return -EINVAL; 14271da177e4SLinus Torvalds } 14281da177e4SLinus Torvalds } 14291da177e4SLinus Torvalds 1430c22c0d63SMichel Lespinasse /* 1431c22c0d63SMichel Lespinasse * Set 'VM_NORESERVE' if we should not account for the 1432c22c0d63SMichel Lespinasse * memory use of this mapping. 1433c22c0d63SMichel Lespinasse */ 1434c22c0d63SMichel Lespinasse if (flags & MAP_NORESERVE) { 1435c22c0d63SMichel Lespinasse /* We honor MAP_NORESERVE if allowed to overcommit */ 1436c22c0d63SMichel Lespinasse if (sysctl_overcommit_memory != OVERCOMMIT_NEVER) 1437c22c0d63SMichel Lespinasse vm_flags |= VM_NORESERVE; 1438c22c0d63SMichel Lespinasse 1439c22c0d63SMichel Lespinasse /* hugetlb applies strict overcommit unless MAP_NORESERVE */ 1440c22c0d63SMichel Lespinasse if (file && is_file_hugepages(file)) 1441c22c0d63SMichel Lespinasse vm_flags |= VM_NORESERVE; 1442c22c0d63SMichel Lespinasse } 1443c22c0d63SMichel Lespinasse 1444897ab3e0SMike Rapoport addr = mmap_region(file, addr, len, vm_flags, pgoff, uf); 144509a9f1d2SMichel Lespinasse if (!IS_ERR_VALUE(addr) && 144609a9f1d2SMichel Lespinasse ((vm_flags & VM_LOCKED) || 144709a9f1d2SMichel Lespinasse (flags & (MAP_POPULATE | MAP_NONBLOCK)) == MAP_POPULATE)) 144841badc15SMichel Lespinasse *populate = len; 1449bebeb3d6SMichel Lespinasse return addr; 14500165ab44SMiklos Szeredi } 14516be5ceb0SLinus Torvalds 1452a90f590aSDominik Brodowski unsigned long ksys_mmap_pgoff(unsigned long addr, unsigned long len, 1453a90f590aSDominik Brodowski unsigned long prot, unsigned long flags, 1454a90f590aSDominik Brodowski unsigned long fd, unsigned long pgoff) 145566f0dc48SHugh Dickins { 145666f0dc48SHugh Dickins struct file *file = NULL; 14571e3ee14bSChen Gang unsigned long retval; 145866f0dc48SHugh Dickins 145966f0dc48SHugh Dickins if (!(flags & MAP_ANONYMOUS)) { 1460120a795dSAl Viro audit_mmap_fd(fd, flags); 146166f0dc48SHugh Dickins file = fget(fd); 146266f0dc48SHugh Dickins if (!file) 14631e3ee14bSChen Gang return -EBADF; 14647bba8f0eSZhen Lei if (is_file_hugepages(file)) { 1465af73e4d9SNaoya Horiguchi len = ALIGN(len, huge_page_size(hstate_file(file))); 14667bba8f0eSZhen Lei } else if (unlikely(flags & MAP_HUGETLB)) { 1467493af578SJörn Engel retval = -EINVAL; 1468493af578SJörn Engel goto out_fput; 14697bba8f0eSZhen Lei } 147066f0dc48SHugh Dickins } else if (flags & MAP_HUGETLB) { 1471c103a4dcSAndrew Morton struct hstate *hs; 1472af73e4d9SNaoya Horiguchi 147320ac2893SAnshuman Khandual hs = hstate_sizelog((flags >> MAP_HUGE_SHIFT) & MAP_HUGE_MASK); 1474091d0d55SLi Zefan if (!hs) 1475091d0d55SLi Zefan return -EINVAL; 1476091d0d55SLi Zefan 1477091d0d55SLi Zefan len = ALIGN(len, huge_page_size(hs)); 147866f0dc48SHugh Dickins /* 147966f0dc48SHugh Dickins * VM_NORESERVE is used because the reservations will be 148066f0dc48SHugh Dickins * taken when vm_ops->mmap() is called 148166f0dc48SHugh Dickins */ 1482af73e4d9SNaoya Horiguchi file = hugetlb_file_setup(HUGETLB_ANON_FILE, len, 148342d7395fSAndi Kleen VM_NORESERVE, 148483c1fd76Szhangyiru HUGETLB_ANONHUGE_INODE, 148542d7395fSAndi Kleen (flags >> MAP_HUGE_SHIFT) & MAP_HUGE_MASK); 148666f0dc48SHugh Dickins if (IS_ERR(file)) 148766f0dc48SHugh Dickins return PTR_ERR(file); 148866f0dc48SHugh Dickins } 148966f0dc48SHugh Dickins 14909fbeb5abSMichal Hocko retval = vm_mmap_pgoff(file, addr, len, prot, flags, pgoff); 1491493af578SJörn Engel out_fput: 149266f0dc48SHugh Dickins if (file) 149366f0dc48SHugh Dickins fput(file); 149466f0dc48SHugh Dickins return retval; 149566f0dc48SHugh Dickins } 149666f0dc48SHugh Dickins 1497a90f590aSDominik Brodowski SYSCALL_DEFINE6(mmap_pgoff, unsigned long, addr, unsigned long, len, 1498a90f590aSDominik Brodowski unsigned long, prot, unsigned long, flags, 1499a90f590aSDominik Brodowski unsigned long, fd, unsigned long, pgoff) 1500a90f590aSDominik Brodowski { 1501a90f590aSDominik Brodowski return ksys_mmap_pgoff(addr, len, prot, flags, fd, pgoff); 1502a90f590aSDominik Brodowski } 1503a90f590aSDominik Brodowski 1504a4679373SChristoph Hellwig #ifdef __ARCH_WANT_SYS_OLD_MMAP 1505a4679373SChristoph Hellwig struct mmap_arg_struct { 1506a4679373SChristoph Hellwig unsigned long addr; 1507a4679373SChristoph Hellwig unsigned long len; 1508a4679373SChristoph Hellwig unsigned long prot; 1509a4679373SChristoph Hellwig unsigned long flags; 1510a4679373SChristoph Hellwig unsigned long fd; 1511a4679373SChristoph Hellwig unsigned long offset; 1512a4679373SChristoph Hellwig }; 1513a4679373SChristoph Hellwig 1514a4679373SChristoph Hellwig SYSCALL_DEFINE1(old_mmap, struct mmap_arg_struct __user *, arg) 1515a4679373SChristoph Hellwig { 1516a4679373SChristoph Hellwig struct mmap_arg_struct a; 1517a4679373SChristoph Hellwig 1518a4679373SChristoph Hellwig if (copy_from_user(&a, arg, sizeof(a))) 1519a4679373SChristoph Hellwig return -EFAULT; 1520de1741a1SAlexander Kuleshov if (offset_in_page(a.offset)) 1521a4679373SChristoph Hellwig return -EINVAL; 1522a4679373SChristoph Hellwig 1523a90f590aSDominik Brodowski return ksys_mmap_pgoff(a.addr, a.len, a.prot, a.flags, a.fd, 1524a4679373SChristoph Hellwig a.offset >> PAGE_SHIFT); 1525a4679373SChristoph Hellwig } 1526a4679373SChristoph Hellwig #endif /* __ARCH_WANT_SYS_OLD_MMAP */ 1527a4679373SChristoph Hellwig 15284e950f6fSAlexey Dobriyan /* 15298bb4e7a2SWei Yang * Some shared mappings will want the pages marked read-only 15304e950f6fSAlexey Dobriyan * to track write events. If so, we'll downgrade vm_page_prot 15314e950f6fSAlexey Dobriyan * to the private version (using protection_map[] without the 15324e950f6fSAlexey Dobriyan * VM_SHARED bit). 15334e950f6fSAlexey Dobriyan */ 15346d2329f8SAndrea Arcangeli int vma_wants_writenotify(struct vm_area_struct *vma, pgprot_t vm_page_prot) 15354e950f6fSAlexey Dobriyan { 1536ca16d140SKOSAKI Motohiro vm_flags_t vm_flags = vma->vm_flags; 15378a04446aSKirill A. Shutemov const struct vm_operations_struct *vm_ops = vma->vm_ops; 15384e950f6fSAlexey Dobriyan 15394e950f6fSAlexey Dobriyan /* If it was private or non-writable, the write bit is already clear */ 15404e950f6fSAlexey Dobriyan if ((vm_flags & (VM_WRITE|VM_SHARED)) != ((VM_WRITE|VM_SHARED))) 15414e950f6fSAlexey Dobriyan return 0; 15424e950f6fSAlexey Dobriyan 15434e950f6fSAlexey Dobriyan /* The backer wishes to know when pages are first written to? */ 15448a04446aSKirill A. Shutemov if (vm_ops && (vm_ops->page_mkwrite || vm_ops->pfn_mkwrite)) 15454e950f6fSAlexey Dobriyan return 1; 15464e950f6fSAlexey Dobriyan 154764e45507SPeter Feiner /* The open routine did something to the protections that pgprot_modify 154864e45507SPeter Feiner * won't preserve? */ 15496d2329f8SAndrea Arcangeli if (pgprot_val(vm_page_prot) != 15506d2329f8SAndrea Arcangeli pgprot_val(vm_pgprot_modify(vm_page_prot, vm_flags))) 15514e950f6fSAlexey Dobriyan return 0; 15524e950f6fSAlexey Dobriyan 1553f96f7a40SDavid Hildenbrand /* 1554f96f7a40SDavid Hildenbrand * Do we need to track softdirty? hugetlb does not support softdirty 1555f96f7a40SDavid Hildenbrand * tracking yet. 1556f96f7a40SDavid Hildenbrand */ 1557f96f7a40SDavid Hildenbrand if (vma_soft_dirty_enabled(vma) && !is_vm_hugetlb_page(vma)) 155864e45507SPeter Feiner return 1; 155964e45507SPeter Feiner 156051d3d5ebSDavid Hildenbrand /* Do we need write faults for uffd-wp tracking? */ 156151d3d5ebSDavid Hildenbrand if (userfaultfd_wp(vma)) 156251d3d5ebSDavid Hildenbrand return 1; 156351d3d5ebSDavid Hildenbrand 15644e950f6fSAlexey Dobriyan /* Specialty mapping? */ 15654b6e1e37SKonstantin Khlebnikov if (vm_flags & VM_PFNMAP) 15664e950f6fSAlexey Dobriyan return 0; 15674e950f6fSAlexey Dobriyan 15684e950f6fSAlexey Dobriyan /* Can the mapping track the dirty pages? */ 15694e950f6fSAlexey Dobriyan return vma->vm_file && vma->vm_file->f_mapping && 1570f56753acSChristoph Hellwig mapping_can_writeback(vma->vm_file->f_mapping); 15714e950f6fSAlexey Dobriyan } 15724e950f6fSAlexey Dobriyan 1573fc8744adSLinus Torvalds /* 1574fc8744adSLinus Torvalds * We account for memory if it's a private writeable mapping, 15755a6fe125SMel Gorman * not hugepages and VM_NORESERVE wasn't set. 1576fc8744adSLinus Torvalds */ 1577ca16d140SKOSAKI Motohiro static inline int accountable_mapping(struct file *file, vm_flags_t vm_flags) 1578fc8744adSLinus Torvalds { 15795a6fe125SMel Gorman /* 15805a6fe125SMel Gorman * hugetlb has its own accounting separate from the core VM 15815a6fe125SMel Gorman * VM_HUGETLB may not be set yet so we cannot check for that flag. 15825a6fe125SMel Gorman */ 15835a6fe125SMel Gorman if (file && is_file_hugepages(file)) 15845a6fe125SMel Gorman return 0; 15855a6fe125SMel Gorman 1586fc8744adSLinus Torvalds return (vm_flags & (VM_NORESERVE | VM_SHARED | VM_WRITE)) == VM_WRITE; 1587fc8744adSLinus Torvalds } 1588fc8744adSLinus Torvalds 15893499a131SLiam R. Howlett /** 15903499a131SLiam R. Howlett * unmapped_area() - Find an area between the low_limit and the high_limit with 15913499a131SLiam R. Howlett * the correct alignment and offset, all from @info. Note: current->mm is used 15923499a131SLiam R. Howlett * for the search. 15933499a131SLiam R. Howlett * 159482b24936SVernon Yang * @info: The unmapped area information including the range [low_limit - 159582b24936SVernon Yang * high_limit), the alignment offset and mask. 15963499a131SLiam R. Howlett * 15973499a131SLiam R. Howlett * Return: A memory address or -ENOMEM. 15983499a131SLiam R. Howlett */ 1599baceaf1cSJaewon Kim static unsigned long unmapped_area(struct vm_unmapped_area_info *info) 1600db4fbfb9SMichel Lespinasse { 16013499a131SLiam R. Howlett unsigned long length, gap; 1602db4fbfb9SMichel Lespinasse 16033499a131SLiam R. Howlett MA_STATE(mas, ¤t->mm->mm_mt, 0, 0); 1604db4fbfb9SMichel Lespinasse 1605db4fbfb9SMichel Lespinasse /* Adjust search length to account for worst case alignment overhead */ 1606db4fbfb9SMichel Lespinasse length = info->length + info->align_mask; 1607db4fbfb9SMichel Lespinasse if (length < info->length) 1608db4fbfb9SMichel Lespinasse return -ENOMEM; 1609db4fbfb9SMichel Lespinasse 16103499a131SLiam R. Howlett if (mas_empty_area(&mas, info->low_limit, info->high_limit - 1, 16113499a131SLiam R. Howlett length)) 16123499a131SLiam R. Howlett return -ENOMEM; 16133499a131SLiam R. Howlett 1614d4af56c5SLiam R. Howlett gap = mas.index; 1615d4af56c5SLiam R. Howlett gap += (info->align_offset - gap) & info->align_mask; 16163499a131SLiam R. Howlett return gap; 1617db4fbfb9SMichel Lespinasse } 1618db4fbfb9SMichel Lespinasse 16193499a131SLiam R. Howlett /** 16203499a131SLiam R. Howlett * unmapped_area_topdown() - Find an area between the low_limit and the 162182b24936SVernon Yang * high_limit with the correct alignment and offset at the highest available 16223499a131SLiam R. Howlett * address, all from @info. Note: current->mm is used for the search. 16233499a131SLiam R. Howlett * 162482b24936SVernon Yang * @info: The unmapped area information including the range [low_limit - 162582b24936SVernon Yang * high_limit), the alignment offset and mask. 16263499a131SLiam R. Howlett * 16273499a131SLiam R. Howlett * Return: A memory address or -ENOMEM. 16283499a131SLiam R. Howlett */ 1629baceaf1cSJaewon Kim static unsigned long unmapped_area_topdown(struct vm_unmapped_area_info *info) 1630db4fbfb9SMichel Lespinasse { 16313499a131SLiam R. Howlett unsigned long length, gap; 1632d4af56c5SLiam R. Howlett 16333499a131SLiam R. Howlett MA_STATE(mas, ¤t->mm->mm_mt, 0, 0); 1634db4fbfb9SMichel Lespinasse /* Adjust search length to account for worst case alignment overhead */ 1635db4fbfb9SMichel Lespinasse length = info->length + info->align_mask; 1636db4fbfb9SMichel Lespinasse if (length < info->length) 1637db4fbfb9SMichel Lespinasse return -ENOMEM; 1638db4fbfb9SMichel Lespinasse 16393499a131SLiam R. Howlett if (mas_empty_area_rev(&mas, info->low_limit, info->high_limit - 1, 16403499a131SLiam R. Howlett length)) 16413499a131SLiam R. Howlett return -ENOMEM; 16423499a131SLiam R. Howlett 1643d4af56c5SLiam R. Howlett gap = mas.last + 1 - info->length; 1644d4af56c5SLiam R. Howlett gap -= (gap - info->align_offset) & info->align_mask; 16453499a131SLiam R. Howlett return gap; 1646db4fbfb9SMichel Lespinasse } 1647db4fbfb9SMichel Lespinasse 1648baceaf1cSJaewon Kim /* 1649baceaf1cSJaewon Kim * Search for an unmapped address range. 1650baceaf1cSJaewon Kim * 1651baceaf1cSJaewon Kim * We are looking for a range that: 1652baceaf1cSJaewon Kim * - does not intersect with any VMA; 1653baceaf1cSJaewon Kim * - is contained within the [low_limit, high_limit) interval; 1654baceaf1cSJaewon Kim * - is at least the desired size. 1655baceaf1cSJaewon Kim * - satisfies (begin_addr & align_mask) == (align_offset & align_mask) 1656baceaf1cSJaewon Kim */ 1657baceaf1cSJaewon Kim unsigned long vm_unmapped_area(struct vm_unmapped_area_info *info) 1658baceaf1cSJaewon Kim { 1659df529cabSJaewon Kim unsigned long addr; 1660df529cabSJaewon Kim 1661baceaf1cSJaewon Kim if (info->flags & VM_UNMAPPED_AREA_TOPDOWN) 1662df529cabSJaewon Kim addr = unmapped_area_topdown(info); 1663baceaf1cSJaewon Kim else 1664df529cabSJaewon Kim addr = unmapped_area(info); 1665df529cabSJaewon Kim 1666df529cabSJaewon Kim trace_vm_unmapped_area(addr, info); 1667df529cabSJaewon Kim return addr; 1668baceaf1cSJaewon Kim } 1669f6795053SSteve Capper 16701da177e4SLinus Torvalds /* Get an address range which is currently unmapped. 16711da177e4SLinus Torvalds * For shmat() with addr=0. 16721da177e4SLinus Torvalds * 16731da177e4SLinus Torvalds * Ugly calling convention alert: 16741da177e4SLinus Torvalds * Return value with the low bits set means error value, 16751da177e4SLinus Torvalds * ie 16761da177e4SLinus Torvalds * if (ret & ~PAGE_MASK) 16771da177e4SLinus Torvalds * error = ret; 16781da177e4SLinus Torvalds * 16791da177e4SLinus Torvalds * This function "knows" that -ENOMEM has the bits set. 16801da177e4SLinus Torvalds */ 16811da177e4SLinus Torvalds unsigned long 16824b439e25SChristophe Leroy generic_get_unmapped_area(struct file *filp, unsigned long addr, 16834b439e25SChristophe Leroy unsigned long len, unsigned long pgoff, 16844b439e25SChristophe Leroy unsigned long flags) 16851da177e4SLinus Torvalds { 16861da177e4SLinus Torvalds struct mm_struct *mm = current->mm; 16871be7107fSHugh Dickins struct vm_area_struct *vma, *prev; 1688db4fbfb9SMichel Lespinasse struct vm_unmapped_area_info info; 16892cb4de08SChristophe Leroy const unsigned long mmap_end = arch_get_mmap_end(addr, len, flags); 16901da177e4SLinus Torvalds 1691f6795053SSteve Capper if (len > mmap_end - mmap_min_addr) 16921da177e4SLinus Torvalds return -ENOMEM; 16931da177e4SLinus Torvalds 169406abdfb4SBenjamin Herrenschmidt if (flags & MAP_FIXED) 169506abdfb4SBenjamin Herrenschmidt return addr; 169606abdfb4SBenjamin Herrenschmidt 16971da177e4SLinus Torvalds if (addr) { 16981da177e4SLinus Torvalds addr = PAGE_ALIGN(addr); 16991be7107fSHugh Dickins vma = find_vma_prev(mm, addr, &prev); 1700f6795053SSteve Capper if (mmap_end - len >= addr && addr >= mmap_min_addr && 17011be7107fSHugh Dickins (!vma || addr + len <= vm_start_gap(vma)) && 17021be7107fSHugh Dickins (!prev || addr >= vm_end_gap(prev))) 17031da177e4SLinus Torvalds return addr; 17041da177e4SLinus Torvalds } 17051da177e4SLinus Torvalds 1706db4fbfb9SMichel Lespinasse info.flags = 0; 1707db4fbfb9SMichel Lespinasse info.length = len; 17084e99b021SHeiko Carstens info.low_limit = mm->mmap_base; 1709f6795053SSteve Capper info.high_limit = mmap_end; 1710db4fbfb9SMichel Lespinasse info.align_mask = 0; 171109ef5283SJaewon Kim info.align_offset = 0; 1712db4fbfb9SMichel Lespinasse return vm_unmapped_area(&info); 17131da177e4SLinus Torvalds } 17144b439e25SChristophe Leroy 17154b439e25SChristophe Leroy #ifndef HAVE_ARCH_UNMAPPED_AREA 17164b439e25SChristophe Leroy unsigned long 17174b439e25SChristophe Leroy arch_get_unmapped_area(struct file *filp, unsigned long addr, 17184b439e25SChristophe Leroy unsigned long len, unsigned long pgoff, 17194b439e25SChristophe Leroy unsigned long flags) 17204b439e25SChristophe Leroy { 17214b439e25SChristophe Leroy return generic_get_unmapped_area(filp, addr, len, pgoff, flags); 17224b439e25SChristophe Leroy } 17231da177e4SLinus Torvalds #endif 17241da177e4SLinus Torvalds 17251da177e4SLinus Torvalds /* 17261da177e4SLinus Torvalds * This mmap-allocator allocates new areas top-down from below the 17271da177e4SLinus Torvalds * stack's low limit (the base): 17281da177e4SLinus Torvalds */ 17291da177e4SLinus Torvalds unsigned long 17304b439e25SChristophe Leroy generic_get_unmapped_area_topdown(struct file *filp, unsigned long addr, 173143cca0b1SYang Fan unsigned long len, unsigned long pgoff, 173243cca0b1SYang Fan unsigned long flags) 17331da177e4SLinus Torvalds { 17341be7107fSHugh Dickins struct vm_area_struct *vma, *prev; 17351da177e4SLinus Torvalds struct mm_struct *mm = current->mm; 1736db4fbfb9SMichel Lespinasse struct vm_unmapped_area_info info; 17372cb4de08SChristophe Leroy const unsigned long mmap_end = arch_get_mmap_end(addr, len, flags); 17381da177e4SLinus Torvalds 17391da177e4SLinus Torvalds /* requested length too big for entire address space */ 1740f6795053SSteve Capper if (len > mmap_end - mmap_min_addr) 17411da177e4SLinus Torvalds return -ENOMEM; 17421da177e4SLinus Torvalds 174306abdfb4SBenjamin Herrenschmidt if (flags & MAP_FIXED) 174406abdfb4SBenjamin Herrenschmidt return addr; 174506abdfb4SBenjamin Herrenschmidt 17461da177e4SLinus Torvalds /* requesting a specific address */ 17471da177e4SLinus Torvalds if (addr) { 17481da177e4SLinus Torvalds addr = PAGE_ALIGN(addr); 17491be7107fSHugh Dickins vma = find_vma_prev(mm, addr, &prev); 1750f6795053SSteve Capper if (mmap_end - len >= addr && addr >= mmap_min_addr && 17511be7107fSHugh Dickins (!vma || addr + len <= vm_start_gap(vma)) && 17521be7107fSHugh Dickins (!prev || addr >= vm_end_gap(prev))) 17531da177e4SLinus Torvalds return addr; 17541da177e4SLinus Torvalds } 17551da177e4SLinus Torvalds 1756db4fbfb9SMichel Lespinasse info.flags = VM_UNMAPPED_AREA_TOPDOWN; 1757db4fbfb9SMichel Lespinasse info.length = len; 17582afc745fSAkira Takeuchi info.low_limit = max(PAGE_SIZE, mmap_min_addr); 1759f6795053SSteve Capper info.high_limit = arch_get_mmap_base(addr, mm->mmap_base); 1760db4fbfb9SMichel Lespinasse info.align_mask = 0; 176109ef5283SJaewon Kim info.align_offset = 0; 1762db4fbfb9SMichel Lespinasse addr = vm_unmapped_area(&info); 1763b716ad95SXiao Guangrong 17641da177e4SLinus Torvalds /* 17651da177e4SLinus Torvalds * A failed mmap() very likely causes application failure, 17661da177e4SLinus Torvalds * so fall back to the bottom-up function here. This scenario 17671da177e4SLinus Torvalds * can happen with large stack limits and large mmap() 17681da177e4SLinus Torvalds * allocations. 17691da177e4SLinus Torvalds */ 1770de1741a1SAlexander Kuleshov if (offset_in_page(addr)) { 1771db4fbfb9SMichel Lespinasse VM_BUG_ON(addr != -ENOMEM); 1772db4fbfb9SMichel Lespinasse info.flags = 0; 1773db4fbfb9SMichel Lespinasse info.low_limit = TASK_UNMAPPED_BASE; 1774f6795053SSteve Capper info.high_limit = mmap_end; 1775db4fbfb9SMichel Lespinasse addr = vm_unmapped_area(&info); 1776db4fbfb9SMichel Lespinasse } 17771da177e4SLinus Torvalds 17781da177e4SLinus Torvalds return addr; 17791da177e4SLinus Torvalds } 17804b439e25SChristophe Leroy 17814b439e25SChristophe Leroy #ifndef HAVE_ARCH_UNMAPPED_AREA_TOPDOWN 17824b439e25SChristophe Leroy unsigned long 17834b439e25SChristophe Leroy arch_get_unmapped_area_topdown(struct file *filp, unsigned long addr, 17844b439e25SChristophe Leroy unsigned long len, unsigned long pgoff, 17854b439e25SChristophe Leroy unsigned long flags) 17864b439e25SChristophe Leroy { 17874b439e25SChristophe Leroy return generic_get_unmapped_area_topdown(filp, addr, len, pgoff, flags); 17884b439e25SChristophe Leroy } 17891da177e4SLinus Torvalds #endif 17901da177e4SLinus Torvalds 17911da177e4SLinus Torvalds unsigned long 17921da177e4SLinus Torvalds get_unmapped_area(struct file *file, unsigned long addr, unsigned long len, 17931da177e4SLinus Torvalds unsigned long pgoff, unsigned long flags) 17941da177e4SLinus Torvalds { 179506abdfb4SBenjamin Herrenschmidt unsigned long (*get_area)(struct file *, unsigned long, 179606abdfb4SBenjamin Herrenschmidt unsigned long, unsigned long, unsigned long); 179707ab67c8SLinus Torvalds 17989206de95SAl Viro unsigned long error = arch_mmap_check(addr, len, flags); 17999206de95SAl Viro if (error) 18009206de95SAl Viro return error; 18019206de95SAl Viro 18029206de95SAl Viro /* Careful about overflows.. */ 18039206de95SAl Viro if (len > TASK_SIZE) 18049206de95SAl Viro return -ENOMEM; 18059206de95SAl Viro 180607ab67c8SLinus Torvalds get_area = current->mm->get_unmapped_area; 1807c01d5b30SHugh Dickins if (file) { 1808c01d5b30SHugh Dickins if (file->f_op->get_unmapped_area) 180907ab67c8SLinus Torvalds get_area = file->f_op->get_unmapped_area; 1810c01d5b30SHugh Dickins } else if (flags & MAP_SHARED) { 1811c01d5b30SHugh Dickins /* 1812c01d5b30SHugh Dickins * mmap_region() will call shmem_zero_setup() to create a file, 1813c01d5b30SHugh Dickins * so use shmem's get_unmapped_area in case it can be huge. 181445e55300SPeter Collingbourne * do_mmap() will clear pgoff, so match alignment. 1815c01d5b30SHugh Dickins */ 1816c01d5b30SHugh Dickins pgoff = 0; 1817c01d5b30SHugh Dickins get_area = shmem_get_unmapped_area; 1818c01d5b30SHugh Dickins } 1819c01d5b30SHugh Dickins 182007ab67c8SLinus Torvalds addr = get_area(file, addr, len, pgoff, flags); 182107ab67c8SLinus Torvalds if (IS_ERR_VALUE(addr)) 182207ab67c8SLinus Torvalds return addr; 182307ab67c8SLinus Torvalds 18241da177e4SLinus Torvalds if (addr > TASK_SIZE - len) 18251da177e4SLinus Torvalds return -ENOMEM; 1826de1741a1SAlexander Kuleshov if (offset_in_page(addr)) 18271da177e4SLinus Torvalds return -EINVAL; 182806abdfb4SBenjamin Herrenschmidt 18299ac4ed4bSAl Viro error = security_mmap_addr(addr); 18309ac4ed4bSAl Viro return error ? error : addr; 18311da177e4SLinus Torvalds } 18321da177e4SLinus Torvalds 18331da177e4SLinus Torvalds EXPORT_SYMBOL(get_unmapped_area); 18341da177e4SLinus Torvalds 1835be8432e7SLiam R. Howlett /** 1836abdba2ddSLiam R. Howlett * find_vma_intersection() - Look up the first VMA which intersects the interval 1837abdba2ddSLiam R. Howlett * @mm: The process address space. 1838abdba2ddSLiam R. Howlett * @start_addr: The inclusive start user address. 1839abdba2ddSLiam R. Howlett * @end_addr: The exclusive end user address. 1840abdba2ddSLiam R. Howlett * 1841abdba2ddSLiam R. Howlett * Returns: The first VMA within the provided range, %NULL otherwise. Assumes 1842abdba2ddSLiam R. Howlett * start_addr < end_addr. 1843abdba2ddSLiam R. Howlett */ 1844abdba2ddSLiam R. Howlett struct vm_area_struct *find_vma_intersection(struct mm_struct *mm, 1845abdba2ddSLiam R. Howlett unsigned long start_addr, 1846abdba2ddSLiam R. Howlett unsigned long end_addr) 1847abdba2ddSLiam R. Howlett { 1848abdba2ddSLiam R. Howlett unsigned long index = start_addr; 1849abdba2ddSLiam R. Howlett 1850abdba2ddSLiam R. Howlett mmap_assert_locked(mm); 18517964cf8cSLiam R. Howlett return mt_find(&mm->mm_mt, &index, end_addr - 1); 1852abdba2ddSLiam R. Howlett } 1853abdba2ddSLiam R. Howlett EXPORT_SYMBOL(find_vma_intersection); 1854abdba2ddSLiam R. Howlett 1855abdba2ddSLiam R. Howlett /** 1856be8432e7SLiam R. Howlett * find_vma() - Find the VMA for a given address, or the next VMA. 1857be8432e7SLiam R. Howlett * @mm: The mm_struct to check 1858be8432e7SLiam R. Howlett * @addr: The address 1859be8432e7SLiam R. Howlett * 1860be8432e7SLiam R. Howlett * Returns: The VMA associated with addr, or the next VMA. 1861be8432e7SLiam R. Howlett * May return %NULL in the case of no VMA at addr or above. 1862be8432e7SLiam R. Howlett */ 18631da177e4SLinus Torvalds struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr) 18641da177e4SLinus Torvalds { 1865be8432e7SLiam R. Howlett unsigned long index = addr; 18661da177e4SLinus Torvalds 18675b78ed24SLuigi Rizzo mmap_assert_locked(mm); 18687964cf8cSLiam R. Howlett return mt_find(&mm->mm_mt, &index, ULONG_MAX); 18691da177e4SLinus Torvalds } 18701da177e4SLinus Torvalds EXPORT_SYMBOL(find_vma); 18711da177e4SLinus Torvalds 18727fdbd37dSLiam R. Howlett /** 18737fdbd37dSLiam R. Howlett * find_vma_prev() - Find the VMA for a given address, or the next vma and 18747fdbd37dSLiam R. Howlett * set %pprev to the previous VMA, if any. 18757fdbd37dSLiam R. Howlett * @mm: The mm_struct to check 18767fdbd37dSLiam R. Howlett * @addr: The address 18777fdbd37dSLiam R. Howlett * @pprev: The pointer to set to the previous VMA 18787fdbd37dSLiam R. Howlett * 18797fdbd37dSLiam R. Howlett * Note that RCU lock is missing here since the external mmap_lock() is used 18807fdbd37dSLiam R. Howlett * instead. 18817fdbd37dSLiam R. Howlett * 18827fdbd37dSLiam R. Howlett * Returns: The VMA associated with @addr, or the next vma. 18837fdbd37dSLiam R. Howlett * May return %NULL in the case of no vma at addr or above. 18846bd4837dSKOSAKI Motohiro */ 18851da177e4SLinus Torvalds struct vm_area_struct * 18861da177e4SLinus Torvalds find_vma_prev(struct mm_struct *mm, unsigned long addr, 18871da177e4SLinus Torvalds struct vm_area_struct **pprev) 18881da177e4SLinus Torvalds { 18896bd4837dSKOSAKI Motohiro struct vm_area_struct *vma; 18907fdbd37dSLiam R. Howlett MA_STATE(mas, &mm->mm_mt, addr, addr); 18911da177e4SLinus Torvalds 18927fdbd37dSLiam R. Howlett vma = mas_walk(&mas); 18937fdbd37dSLiam R. Howlett *pprev = mas_prev(&mas, 0); 18947fdbd37dSLiam R. Howlett if (!vma) 18957fdbd37dSLiam R. Howlett vma = mas_next(&mas, ULONG_MAX); 18966bd4837dSKOSAKI Motohiro return vma; 18971da177e4SLinus Torvalds } 18981da177e4SLinus Torvalds 18991da177e4SLinus Torvalds /* 19001da177e4SLinus Torvalds * Verify that the stack growth is acceptable and 19011da177e4SLinus Torvalds * update accounting. This is shared with both the 19021da177e4SLinus Torvalds * grow-up and grow-down cases. 19031da177e4SLinus Torvalds */ 19041be7107fSHugh Dickins static int acct_stack_growth(struct vm_area_struct *vma, 19051be7107fSHugh Dickins unsigned long size, unsigned long grow) 19061da177e4SLinus Torvalds { 19071da177e4SLinus Torvalds struct mm_struct *mm = vma->vm_mm; 19081be7107fSHugh Dickins unsigned long new_start; 19091da177e4SLinus Torvalds 19101da177e4SLinus Torvalds /* address space limit tests */ 191184638335SKonstantin Khlebnikov if (!may_expand_vm(mm, vma->vm_flags, grow)) 19121da177e4SLinus Torvalds return -ENOMEM; 19131da177e4SLinus Torvalds 19141da177e4SLinus Torvalds /* Stack limit test */ 191524c79d8eSKrzysztof Opasiak if (size > rlimit(RLIMIT_STACK)) 19161da177e4SLinus Torvalds return -ENOMEM; 19171da177e4SLinus Torvalds 19181da177e4SLinus Torvalds /* mlock limit tests */ 1919c5d8a364SMiaohe Lin if (mlock_future_check(mm, vma->vm_flags, grow << PAGE_SHIFT)) 19201da177e4SLinus Torvalds return -ENOMEM; 19211da177e4SLinus Torvalds 19220d59a01bSAdam Litke /* Check to ensure the stack will not grow into a hugetlb-only region */ 19230d59a01bSAdam Litke new_start = (vma->vm_flags & VM_GROWSUP) ? vma->vm_start : 19240d59a01bSAdam Litke vma->vm_end - size; 19250d59a01bSAdam Litke if (is_hugepage_only_range(vma->vm_mm, new_start, size)) 19260d59a01bSAdam Litke return -EFAULT; 19270d59a01bSAdam Litke 19281da177e4SLinus Torvalds /* 19291da177e4SLinus Torvalds * Overcommit.. This must be the final test, as it will 19301da177e4SLinus Torvalds * update security statistics. 19311da177e4SLinus Torvalds */ 193205fa199dSHugh Dickins if (security_vm_enough_memory_mm(mm, grow)) 19331da177e4SLinus Torvalds return -ENOMEM; 19341da177e4SLinus Torvalds 19351da177e4SLinus Torvalds return 0; 19361da177e4SLinus Torvalds } 19371da177e4SLinus Torvalds 193846dea3d0SHugh Dickins #if defined(CONFIG_STACK_GROWSUP) || defined(CONFIG_IA64) 19391da177e4SLinus Torvalds /* 194046dea3d0SHugh Dickins * PA-RISC uses this for its stack; IA64 for its Register Backing Store. 194146dea3d0SHugh Dickins * vma is the last one with address > vma->vm_end. Have to extend vma. 19421da177e4SLinus Torvalds */ 194346dea3d0SHugh Dickins int expand_upwards(struct vm_area_struct *vma, unsigned long address) 19441da177e4SLinus Torvalds { 194509357814SOleg Nesterov struct mm_struct *mm = vma->vm_mm; 19461be7107fSHugh Dickins struct vm_area_struct *next; 19471be7107fSHugh Dickins unsigned long gap_addr; 194812352d3cSKonstantin Khlebnikov int error = 0; 1949d4af56c5SLiam R. Howlett MA_STATE(mas, &mm->mm_mt, 0, 0); 19501da177e4SLinus Torvalds 19511da177e4SLinus Torvalds if (!(vma->vm_flags & VM_GROWSUP)) 19521da177e4SLinus Torvalds return -EFAULT; 19531da177e4SLinus Torvalds 1954bd726c90SHelge Deller /* Guard against exceeding limits of the address space. */ 19551be7107fSHugh Dickins address &= PAGE_MASK; 195637511fb5SHelge Deller if (address >= (TASK_SIZE & PAGE_MASK)) 195712352d3cSKonstantin Khlebnikov return -ENOMEM; 1958bd726c90SHelge Deller address += PAGE_SIZE; 195912352d3cSKonstantin Khlebnikov 19601be7107fSHugh Dickins /* Enforce stack_guard_gap */ 19611be7107fSHugh Dickins gap_addr = address + stack_guard_gap; 1962bd726c90SHelge Deller 1963bd726c90SHelge Deller /* Guard against overflow */ 1964bd726c90SHelge Deller if (gap_addr < address || gap_addr > TASK_SIZE) 1965bd726c90SHelge Deller gap_addr = TASK_SIZE; 1966bd726c90SHelge Deller 1967763ecb03SLiam R. Howlett next = find_vma_intersection(mm, vma->vm_end, gap_addr); 1968763ecb03SLiam R. Howlett if (next && vma_is_accessible(next)) { 19691be7107fSHugh Dickins if (!(next->vm_flags & VM_GROWSUP)) 19701be7107fSHugh Dickins return -ENOMEM; 19711be7107fSHugh Dickins /* Check that both stack segments have the same anon_vma? */ 19721be7107fSHugh Dickins } 19731be7107fSHugh Dickins 1974c5d5546eSVernon Yang if (mas_preallocate(&mas, GFP_KERNEL)) 19751da177e4SLinus Torvalds return -ENOMEM; 19761da177e4SLinus Torvalds 1977d4af56c5SLiam R. Howlett /* We must make sure the anon_vma is allocated. */ 1978d4af56c5SLiam R. Howlett if (unlikely(anon_vma_prepare(vma))) { 1979d4af56c5SLiam R. Howlett mas_destroy(&mas); 1980d4af56c5SLiam R. Howlett return -ENOMEM; 1981d4af56c5SLiam R. Howlett } 1982d4af56c5SLiam R. Howlett 19831da177e4SLinus Torvalds /* 19841da177e4SLinus Torvalds * vma->vm_start/vm_end cannot change under us because the caller 1985c1e8d7c6SMichel Lespinasse * is required to hold the mmap_lock in read mode. We need the 19861da177e4SLinus Torvalds * anon_vma lock to serialize against concurrent expand_stacks. 19871da177e4SLinus Torvalds */ 198812352d3cSKonstantin Khlebnikov anon_vma_lock_write(vma->anon_vma); 19891da177e4SLinus Torvalds 19901da177e4SLinus Torvalds /* Somebody else might have raced and expanded it already */ 19911da177e4SLinus Torvalds if (address > vma->vm_end) { 19921da177e4SLinus Torvalds unsigned long size, grow; 19931da177e4SLinus Torvalds 19941da177e4SLinus Torvalds size = address - vma->vm_start; 19951da177e4SLinus Torvalds grow = (address - vma->vm_end) >> PAGE_SHIFT; 19961da177e4SLinus Torvalds 199742c36f63SHugh Dickins error = -ENOMEM; 199842c36f63SHugh Dickins if (vma->vm_pgoff + (size >> PAGE_SHIFT) >= vma->vm_pgoff) { 19991da177e4SLinus Torvalds error = acct_stack_growth(vma, size, grow); 20003af9e859SEric B Munson if (!error) { 20014128997bSMichel Lespinasse /* 2002524e00b3SLiam R. Howlett * We only hold a shared mmap_lock lock here, so 2003524e00b3SLiam R. Howlett * we need to protect against concurrent vma 2004524e00b3SLiam R. Howlett * expansions. anon_vma_lock_write() doesn't 2005524e00b3SLiam R. Howlett * help here, as we don't guarantee that all 2006524e00b3SLiam R. Howlett * growable vmas in a mm share the same root 2007524e00b3SLiam R. Howlett * anon vma. So, we reuse mm->page_table_lock 2008524e00b3SLiam R. Howlett * to guard against concurrent vma expansions. 20094128997bSMichel Lespinasse */ 201009357814SOleg Nesterov spin_lock(&mm->page_table_lock); 201187e8827bSOleg Nesterov if (vma->vm_flags & VM_LOCKED) 201209357814SOleg Nesterov mm->locked_vm += grow; 201384638335SKonstantin Khlebnikov vm_stat_account(mm, vma->vm_flags, grow); 2014bf181b9fSMichel Lespinasse anon_vma_interval_tree_pre_update_vma(vma); 20151da177e4SLinus Torvalds vma->vm_end = address; 2016d4af56c5SLiam R. Howlett /* Overwrite old entry in mtree. */ 2017d4af56c5SLiam R. Howlett vma_mas_store(vma, &mas); 2018bf181b9fSMichel Lespinasse anon_vma_interval_tree_post_update_vma(vma); 201909357814SOleg Nesterov spin_unlock(&mm->page_table_lock); 20204128997bSMichel Lespinasse 20213af9e859SEric B Munson perf_event_mmap(vma); 20223af9e859SEric B Munson } 20231da177e4SLinus Torvalds } 202442c36f63SHugh Dickins } 202512352d3cSKonstantin Khlebnikov anon_vma_unlock_write(vma->anon_vma); 2026c791576cSYang Shi khugepaged_enter_vma(vma, vma->vm_flags); 2027d4af56c5SLiam R. Howlett mas_destroy(&mas); 20281da177e4SLinus Torvalds return error; 20291da177e4SLinus Torvalds } 203046dea3d0SHugh Dickins #endif /* CONFIG_STACK_GROWSUP || CONFIG_IA64 */ 203146dea3d0SHugh Dickins 20321da177e4SLinus Torvalds /* 20331da177e4SLinus Torvalds * vma is the first one with address < vma->vm_start. Have to extend vma. 20341da177e4SLinus Torvalds */ 2035524e00b3SLiam R. Howlett int expand_downwards(struct vm_area_struct *vma, unsigned long address) 20361da177e4SLinus Torvalds { 203709357814SOleg Nesterov struct mm_struct *mm = vma->vm_mm; 2038763ecb03SLiam R. Howlett MA_STATE(mas, &mm->mm_mt, vma->vm_start, vma->vm_start); 20391be7107fSHugh Dickins struct vm_area_struct *prev; 20400a1d5299SJann Horn int error = 0; 20411da177e4SLinus Torvalds 20428869477aSEric Paris address &= PAGE_MASK; 20430a1d5299SJann Horn if (address < mmap_min_addr) 20440a1d5299SJann Horn return -EPERM; 20458869477aSEric Paris 20461be7107fSHugh Dickins /* Enforce stack_guard_gap */ 2047763ecb03SLiam R. Howlett prev = mas_prev(&mas, 0); 20481be7107fSHugh Dickins /* Check that both stack segments have the same anon_vma? */ 204932e4e6d5SOleg Nesterov if (prev && !(prev->vm_flags & VM_GROWSDOWN) && 20503122e80eSAnshuman Khandual vma_is_accessible(prev)) { 205132e4e6d5SOleg Nesterov if (address - prev->vm_end < stack_guard_gap) 205232e4e6d5SOleg Nesterov return -ENOMEM; 20531be7107fSHugh Dickins } 20541be7107fSHugh Dickins 2055c5d5546eSVernon Yang if (mas_preallocate(&mas, GFP_KERNEL)) 205612352d3cSKonstantin Khlebnikov return -ENOMEM; 20571da177e4SLinus Torvalds 2058d4af56c5SLiam R. Howlett /* We must make sure the anon_vma is allocated. */ 2059d4af56c5SLiam R. Howlett if (unlikely(anon_vma_prepare(vma))) { 2060d4af56c5SLiam R. Howlett mas_destroy(&mas); 2061d4af56c5SLiam R. Howlett return -ENOMEM; 2062d4af56c5SLiam R. Howlett } 2063d4af56c5SLiam R. Howlett 20641da177e4SLinus Torvalds /* 20651da177e4SLinus Torvalds * vma->vm_start/vm_end cannot change under us because the caller 2066c1e8d7c6SMichel Lespinasse * is required to hold the mmap_lock in read mode. We need the 20671da177e4SLinus Torvalds * anon_vma lock to serialize against concurrent expand_stacks. 20681da177e4SLinus Torvalds */ 206912352d3cSKonstantin Khlebnikov anon_vma_lock_write(vma->anon_vma); 20701da177e4SLinus Torvalds 20711da177e4SLinus Torvalds /* Somebody else might have raced and expanded it already */ 20721da177e4SLinus Torvalds if (address < vma->vm_start) { 20731da177e4SLinus Torvalds unsigned long size, grow; 20741da177e4SLinus Torvalds 20751da177e4SLinus Torvalds size = vma->vm_end - address; 20761da177e4SLinus Torvalds grow = (vma->vm_start - address) >> PAGE_SHIFT; 20771da177e4SLinus Torvalds 2078a626ca6aSLinus Torvalds error = -ENOMEM; 2079a626ca6aSLinus Torvalds if (grow <= vma->vm_pgoff) { 20801da177e4SLinus Torvalds error = acct_stack_growth(vma, size, grow); 20811da177e4SLinus Torvalds if (!error) { 20824128997bSMichel Lespinasse /* 2083524e00b3SLiam R. Howlett * We only hold a shared mmap_lock lock here, so 2084524e00b3SLiam R. Howlett * we need to protect against concurrent vma 2085524e00b3SLiam R. Howlett * expansions. anon_vma_lock_write() doesn't 2086524e00b3SLiam R. Howlett * help here, as we don't guarantee that all 2087524e00b3SLiam R. Howlett * growable vmas in a mm share the same root 2088524e00b3SLiam R. Howlett * anon vma. So, we reuse mm->page_table_lock 2089524e00b3SLiam R. Howlett * to guard against concurrent vma expansions. 20904128997bSMichel Lespinasse */ 209109357814SOleg Nesterov spin_lock(&mm->page_table_lock); 209287e8827bSOleg Nesterov if (vma->vm_flags & VM_LOCKED) 209309357814SOleg Nesterov mm->locked_vm += grow; 209484638335SKonstantin Khlebnikov vm_stat_account(mm, vma->vm_flags, grow); 2095bf181b9fSMichel Lespinasse anon_vma_interval_tree_pre_update_vma(vma); 20961da177e4SLinus Torvalds vma->vm_start = address; 20971da177e4SLinus Torvalds vma->vm_pgoff -= grow; 2098d4af56c5SLiam R. Howlett /* Overwrite old entry in mtree. */ 2099d4af56c5SLiam R. Howlett vma_mas_store(vma, &mas); 2100bf181b9fSMichel Lespinasse anon_vma_interval_tree_post_update_vma(vma); 210109357814SOleg Nesterov spin_unlock(&mm->page_table_lock); 21024128997bSMichel Lespinasse 21033af9e859SEric B Munson perf_event_mmap(vma); 21041da177e4SLinus Torvalds } 21051da177e4SLinus Torvalds } 2106a626ca6aSLinus Torvalds } 210712352d3cSKonstantin Khlebnikov anon_vma_unlock_write(vma->anon_vma); 2108c791576cSYang Shi khugepaged_enter_vma(vma, vma->vm_flags); 2109d4af56c5SLiam R. Howlett mas_destroy(&mas); 21101da177e4SLinus Torvalds return error; 21111da177e4SLinus Torvalds } 21121da177e4SLinus Torvalds 21131be7107fSHugh Dickins /* enforced gap between the expanding stack and other mappings. */ 21141be7107fSHugh Dickins unsigned long stack_guard_gap = 256UL<<PAGE_SHIFT; 21151be7107fSHugh Dickins 21161be7107fSHugh Dickins static int __init cmdline_parse_stack_guard_gap(char *p) 21171be7107fSHugh Dickins { 21181be7107fSHugh Dickins unsigned long val; 21191be7107fSHugh Dickins char *endptr; 21201be7107fSHugh Dickins 21211be7107fSHugh Dickins val = simple_strtoul(p, &endptr, 10); 21221be7107fSHugh Dickins if (!*endptr) 21231be7107fSHugh Dickins stack_guard_gap = val << PAGE_SHIFT; 21241be7107fSHugh Dickins 2125e6d09493SRandy Dunlap return 1; 21261be7107fSHugh Dickins } 21271be7107fSHugh Dickins __setup("stack_guard_gap=", cmdline_parse_stack_guard_gap); 21281be7107fSHugh Dickins 2129b6a2fea3SOllie Wild #ifdef CONFIG_STACK_GROWSUP 2130b6a2fea3SOllie Wild int expand_stack(struct vm_area_struct *vma, unsigned long address) 2131b6a2fea3SOllie Wild { 2132b6a2fea3SOllie Wild return expand_upwards(vma, address); 2133b6a2fea3SOllie Wild } 2134b6a2fea3SOllie Wild 2135b6a2fea3SOllie Wild struct vm_area_struct * 2136b6a2fea3SOllie Wild find_extend_vma(struct mm_struct *mm, unsigned long addr) 2137b6a2fea3SOllie Wild { 2138b6a2fea3SOllie Wild struct vm_area_struct *vma, *prev; 2139b6a2fea3SOllie Wild 2140b6a2fea3SOllie Wild addr &= PAGE_MASK; 2141b6a2fea3SOllie Wild vma = find_vma_prev(mm, addr, &prev); 2142b6a2fea3SOllie Wild if (vma && (vma->vm_start <= addr)) 2143b6a2fea3SOllie Wild return vma; 21444d45e75aSJann Horn if (!prev || expand_stack(prev, addr)) 2145b6a2fea3SOllie Wild return NULL; 2146cea10a19SMichel Lespinasse if (prev->vm_flags & VM_LOCKED) 2147fc05f566SKirill A. Shutemov populate_vma_page_range(prev, addr, prev->vm_end, NULL); 2148b6a2fea3SOllie Wild return prev; 2149b6a2fea3SOllie Wild } 2150b6a2fea3SOllie Wild #else 2151b6a2fea3SOllie Wild int expand_stack(struct vm_area_struct *vma, unsigned long address) 2152b6a2fea3SOllie Wild { 2153b6a2fea3SOllie Wild return expand_downwards(vma, address); 2154b6a2fea3SOllie Wild } 2155b6a2fea3SOllie Wild 21561da177e4SLinus Torvalds struct vm_area_struct * 21571da177e4SLinus Torvalds find_extend_vma(struct mm_struct *mm, unsigned long addr) 21581da177e4SLinus Torvalds { 21591da177e4SLinus Torvalds struct vm_area_struct *vma; 21601da177e4SLinus Torvalds unsigned long start; 21611da177e4SLinus Torvalds 21621da177e4SLinus Torvalds addr &= PAGE_MASK; 21631da177e4SLinus Torvalds vma = find_vma(mm, addr); 21641da177e4SLinus Torvalds if (!vma) 21651da177e4SLinus Torvalds return NULL; 21661da177e4SLinus Torvalds if (vma->vm_start <= addr) 21671da177e4SLinus Torvalds return vma; 21681da177e4SLinus Torvalds if (!(vma->vm_flags & VM_GROWSDOWN)) 21691da177e4SLinus Torvalds return NULL; 21701da177e4SLinus Torvalds start = vma->vm_start; 21711da177e4SLinus Torvalds if (expand_stack(vma, addr)) 21721da177e4SLinus Torvalds return NULL; 2173cea10a19SMichel Lespinasse if (vma->vm_flags & VM_LOCKED) 2174fc05f566SKirill A. Shutemov populate_vma_page_range(vma, addr, start, NULL); 21751da177e4SLinus Torvalds return vma; 21761da177e4SLinus Torvalds } 21771da177e4SLinus Torvalds #endif 21781da177e4SLinus Torvalds 2179e1d6d01aSJesse Barnes EXPORT_SYMBOL_GPL(find_extend_vma); 2180e1d6d01aSJesse Barnes 21812c0b3814SHugh Dickins /* 2182763ecb03SLiam R. Howlett * Ok - we have the memory areas we should free on a maple tree so release them, 2183763ecb03SLiam R. Howlett * and do the vma updates. 21841da177e4SLinus Torvalds * 21852c0b3814SHugh Dickins * Called with the mm semaphore held. 21861da177e4SLinus Torvalds */ 2187763ecb03SLiam R. Howlett static inline void remove_mt(struct mm_struct *mm, struct ma_state *mas) 21881da177e4SLinus Torvalds { 21894f74d2c8SLinus Torvalds unsigned long nr_accounted = 0; 2190763ecb03SLiam R. Howlett struct vm_area_struct *vma; 21914f74d2c8SLinus Torvalds 2192365e9c87SHugh Dickins /* Update high watermark before we lower total_vm */ 2193365e9c87SHugh Dickins update_hiwater_vm(mm); 2194763ecb03SLiam R. Howlett mas_for_each(mas, vma, ULONG_MAX) { 2195ab50b8edSHugh Dickins long nrpages = vma_pages(vma); 21961da177e4SLinus Torvalds 21974f74d2c8SLinus Torvalds if (vma->vm_flags & VM_ACCOUNT) 21984f74d2c8SLinus Torvalds nr_accounted += nrpages; 219984638335SKonstantin Khlebnikov vm_stat_account(mm, vma->vm_flags, -nrpages); 2200763ecb03SLiam R. Howlett remove_vma(vma); 2201763ecb03SLiam R. Howlett } 22024f74d2c8SLinus Torvalds vm_unacct_memory(nr_accounted); 22031da177e4SLinus Torvalds validate_mm(mm); 22041da177e4SLinus Torvalds } 22051da177e4SLinus Torvalds 22061da177e4SLinus Torvalds /* 22071da177e4SLinus Torvalds * Get rid of page table information in the indicated region. 22081da177e4SLinus Torvalds * 2209f10df686SPaolo 'Blaisorblade' Giarrusso * Called with the mm semaphore held. 22101da177e4SLinus Torvalds */ 2211763ecb03SLiam R. Howlett static void unmap_region(struct mm_struct *mm, struct maple_tree *mt, 2212e0da382cSHugh Dickins struct vm_area_struct *vma, struct vm_area_struct *prev, 2213763ecb03SLiam R. Howlett struct vm_area_struct *next, 2214e0da382cSHugh Dickins unsigned long start, unsigned long end) 22151da177e4SLinus Torvalds { 2216d16dfc55SPeter Zijlstra struct mmu_gather tlb; 22171da177e4SLinus Torvalds 22181da177e4SLinus Torvalds lru_add_drain(); 2219a72afd87SWill Deacon tlb_gather_mmu(&tlb, mm); 2220365e9c87SHugh Dickins update_hiwater_rss(mm); 2221763ecb03SLiam R. Howlett unmap_vmas(&tlb, mt, vma, start, end); 2222763ecb03SLiam R. Howlett free_pgtables(&tlb, mt, vma, prev ? prev->vm_end : FIRST_USER_ADDRESS, 22236ee8630eSHugh Dickins next ? next->vm_start : USER_PGTABLES_CEILING); 2224ae8eba8bSWill Deacon tlb_finish_mmu(&tlb); 22251da177e4SLinus Torvalds } 22261da177e4SLinus Torvalds 22271da177e4SLinus Torvalds /* 2228def5efe0SDavid Rientjes * __split_vma() bypasses sysctl_max_map_count checking. We use this where it 2229def5efe0SDavid Rientjes * has already been checked or doesn't make sense to fail. 22301da177e4SLinus Torvalds */ 2231def5efe0SDavid Rientjes int __split_vma(struct mm_struct *mm, struct vm_area_struct *vma, 22321da177e4SLinus Torvalds unsigned long addr, int new_below) 22331da177e4SLinus Torvalds { 22341da177e4SLinus Torvalds struct vm_area_struct *new; 2235e3975891SChen Gang int err; 2236d4af56c5SLiam R. Howlett validate_mm_mt(mm); 22371da177e4SLinus Torvalds 2238dd3b614fSDmitry Safonov if (vma->vm_ops && vma->vm_ops->may_split) { 2239dd3b614fSDmitry Safonov err = vma->vm_ops->may_split(vma, addr); 224031383c68SDan Williams if (err) 224131383c68SDan Williams return err; 224231383c68SDan Williams } 22431da177e4SLinus Torvalds 22443928d4f5SLinus Torvalds new = vm_area_dup(vma); 22451da177e4SLinus Torvalds if (!new) 2246e3975891SChen Gang return -ENOMEM; 22471da177e4SLinus Torvalds 22481da177e4SLinus Torvalds if (new_below) 22491da177e4SLinus Torvalds new->vm_end = addr; 22501da177e4SLinus Torvalds else { 22511da177e4SLinus Torvalds new->vm_start = addr; 22521da177e4SLinus Torvalds new->vm_pgoff += ((addr - vma->vm_start) >> PAGE_SHIFT); 22531da177e4SLinus Torvalds } 22541da177e4SLinus Torvalds 2255ef0855d3SOleg Nesterov err = vma_dup_policy(vma, new); 2256ef0855d3SOleg Nesterov if (err) 22575beb4930SRik van Riel goto out_free_vma; 22581da177e4SLinus Torvalds 2259c4ea95d7SDaniel Forrest err = anon_vma_clone(new, vma); 2260c4ea95d7SDaniel Forrest if (err) 22615beb4930SRik van Riel goto out_free_mpol; 22625beb4930SRik van Riel 2263e9714acfSKonstantin Khlebnikov if (new->vm_file) 22641da177e4SLinus Torvalds get_file(new->vm_file); 22651da177e4SLinus Torvalds 22661da177e4SLinus Torvalds if (new->vm_ops && new->vm_ops->open) 22671da177e4SLinus Torvalds new->vm_ops->open(new); 22681da177e4SLinus Torvalds 22691da177e4SLinus Torvalds if (new_below) 22705beb4930SRik van Riel err = vma_adjust(vma, addr, vma->vm_end, vma->vm_pgoff + 22711da177e4SLinus Torvalds ((addr - new->vm_start) >> PAGE_SHIFT), new); 22721da177e4SLinus Torvalds else 22735beb4930SRik van Riel err = vma_adjust(vma, vma->vm_start, addr, vma->vm_pgoff, new); 22741da177e4SLinus Torvalds 22755beb4930SRik van Riel /* Success. */ 22765beb4930SRik van Riel if (!err) 22771da177e4SLinus Torvalds return 0; 22785beb4930SRik van Riel 2279d4af56c5SLiam R. Howlett /* Avoid vm accounting in close() operation */ 2280d4af56c5SLiam R. Howlett new->vm_start = new->vm_end; 2281d4af56c5SLiam R. Howlett new->vm_pgoff = 0; 22825beb4930SRik van Riel /* Clean everything up if vma_adjust failed. */ 228358927533SRik van Riel if (new->vm_ops && new->vm_ops->close) 22845beb4930SRik van Riel new->vm_ops->close(new); 2285e9714acfSKonstantin Khlebnikov if (new->vm_file) 22865beb4930SRik van Riel fput(new->vm_file); 22872aeadc30SAndrea Arcangeli unlink_anon_vmas(new); 22885beb4930SRik van Riel out_free_mpol: 2289ef0855d3SOleg Nesterov mpol_put(vma_policy(new)); 22905beb4930SRik van Riel out_free_vma: 22913928d4f5SLinus Torvalds vm_area_free(new); 2292d4af56c5SLiam R. Howlett validate_mm_mt(mm); 22935beb4930SRik van Riel return err; 22941da177e4SLinus Torvalds } 2295f2ebfe43SLiam R. Howlett int vmi__split_vma(struct vma_iterator *vmi, struct mm_struct *mm, 2296f2ebfe43SLiam R. Howlett struct vm_area_struct *vma, unsigned long addr, int new_below) 2297f2ebfe43SLiam R. Howlett { 2298f2ebfe43SLiam R. Howlett int ret; 2299f2ebfe43SLiam R. Howlett unsigned long end = vma->vm_end; 2300f2ebfe43SLiam R. Howlett 2301f2ebfe43SLiam R. Howlett ret = __split_vma(mm, vma, addr, new_below); 2302f2ebfe43SLiam R. Howlett if (!ret) 2303f2ebfe43SLiam R. Howlett vma_iter_set(vmi, end); 2304f2ebfe43SLiam R. Howlett 2305f2ebfe43SLiam R. Howlett return ret; 2306f2ebfe43SLiam R. Howlett } 23071da177e4SLinus Torvalds 2308659ace58SKOSAKI Motohiro /* 2309659ace58SKOSAKI Motohiro * Split a vma into two pieces at address 'addr', a new vma is allocated 2310659ace58SKOSAKI Motohiro * either for the first part or the tail. 2311659ace58SKOSAKI Motohiro */ 2312659ace58SKOSAKI Motohiro int split_vma(struct mm_struct *mm, struct vm_area_struct *vma, 2313659ace58SKOSAKI Motohiro unsigned long addr, int new_below) 2314659ace58SKOSAKI Motohiro { 2315659ace58SKOSAKI Motohiro if (mm->map_count >= sysctl_max_map_count) 2316659ace58SKOSAKI Motohiro return -ENOMEM; 2317659ace58SKOSAKI Motohiro 2318659ace58SKOSAKI Motohiro return __split_vma(mm, vma, addr, new_below); 2319659ace58SKOSAKI Motohiro } 2320659ace58SKOSAKI Motohiro 2321f2ebfe43SLiam R. Howlett int vmi_split_vma(struct vma_iterator *vmi, struct mm_struct *mm, 2322f2ebfe43SLiam R. Howlett struct vm_area_struct *vma, unsigned long addr, int new_below) 2323f2ebfe43SLiam R. Howlett { 2324f2ebfe43SLiam R. Howlett int ret; 2325f2ebfe43SLiam R. Howlett unsigned long end = vma->vm_end; 2326f2ebfe43SLiam R. Howlett 2327f2ebfe43SLiam R. Howlett ret = split_vma(mm, vma, addr, new_below); 2328f2ebfe43SLiam R. Howlett if (!ret) 2329f2ebfe43SLiam R. Howlett vma_iter_set(vmi, end); 2330f2ebfe43SLiam R. Howlett 2331f2ebfe43SLiam R. Howlett return ret; 2332f2ebfe43SLiam R. Howlett } 2333f2ebfe43SLiam R. Howlett 2334763ecb03SLiam R. Howlett static inline int munmap_sidetree(struct vm_area_struct *vma, 2335763ecb03SLiam R. Howlett struct ma_state *mas_detach) 23361da177e4SLinus Torvalds { 2337763ecb03SLiam R. Howlett mas_set_range(mas_detach, vma->vm_start, vma->vm_end - 1); 2338763ecb03SLiam R. Howlett if (mas_store_gfp(mas_detach, vma, GFP_KERNEL)) 2339763ecb03SLiam R. Howlett return -ENOMEM; 234011f9a21aSLiam R. Howlett 2341763ecb03SLiam R. Howlett if (vma->vm_flags & VM_LOCKED) 2342763ecb03SLiam R. Howlett vma->vm_mm->locked_vm -= vma_pages(vma); 234311f9a21aSLiam R. Howlett 2344763ecb03SLiam R. Howlett return 0; 234511f9a21aSLiam R. Howlett } 234611f9a21aSLiam R. Howlett 234711f9a21aSLiam R. Howlett /* 2348183654ceSLiam R. Howlett * do_vmi_align_munmap() - munmap the aligned region from @start to @end. 2349183654ceSLiam R. Howlett * @vmi: The vma iterator 235011f9a21aSLiam R. Howlett * @vma: The starting vm_area_struct 235111f9a21aSLiam R. Howlett * @mm: The mm_struct 235211f9a21aSLiam R. Howlett * @start: The aligned start address to munmap. 235311f9a21aSLiam R. Howlett * @end: The aligned end address to munmap. 235411f9a21aSLiam R. Howlett * @uf: The userfaultfd list_head 23558651a137SLorenzo Stoakes * @downgrade: Set to true to attempt a write downgrade of the mmap_lock 235611f9a21aSLiam R. Howlett * 235711f9a21aSLiam R. Howlett * If @downgrade is true, check return code for potential release of the lock. 235811f9a21aSLiam R. Howlett */ 235911f9a21aSLiam R. Howlett static int 2360183654ceSLiam R. Howlett do_vmi_align_munmap(struct vma_iterator *vmi, struct vm_area_struct *vma, 236111f9a21aSLiam R. Howlett struct mm_struct *mm, unsigned long start, 236211f9a21aSLiam R. Howlett unsigned long end, struct list_head *uf, bool downgrade) 236311f9a21aSLiam R. Howlett { 2364763ecb03SLiam R. Howlett struct vm_area_struct *prev, *next = NULL; 2365763ecb03SLiam R. Howlett struct maple_tree mt_detach; 2366763ecb03SLiam R. Howlett int count = 0; 2367d4af56c5SLiam R. Howlett int error = -ENOMEM; 2368763ecb03SLiam R. Howlett MA_STATE(mas_detach, &mt_detach, 0, 0); 2369763ecb03SLiam R. Howlett mt_init_flags(&mt_detach, MT_FLAGS_LOCK_EXTERN); 2370763ecb03SLiam R. Howlett mt_set_external_lock(&mt_detach, &mm->mmap_lock); 2371524e00b3SLiam R. Howlett 23721da177e4SLinus Torvalds /* 23731da177e4SLinus Torvalds * If we need to split any vma, do it now to save pain later. 23741da177e4SLinus Torvalds * 23751da177e4SLinus Torvalds * Note: mremap's move_vma VM_ACCOUNT handling assumes a partially 23761da177e4SLinus Torvalds * unmapped vm_area_struct will remain in use: so lower split_vma 23771da177e4SLinus Torvalds * places tmp vma above, and higher split_vma places tmp vma below. 23781da177e4SLinus Torvalds */ 2379763ecb03SLiam R. Howlett 2380763ecb03SLiam R. Howlett /* Does it split the first one? */ 2381146425a3SHugh Dickins if (start > vma->vm_start) { 2382659ace58SKOSAKI Motohiro 2383659ace58SKOSAKI Motohiro /* 2384659ace58SKOSAKI Motohiro * Make sure that map_count on return from munmap() will 2385659ace58SKOSAKI Motohiro * not exceed its limit; but let map_count go just above 2386659ace58SKOSAKI Motohiro * its limit temporarily, to help free resources as expected. 2387659ace58SKOSAKI Motohiro */ 2388659ace58SKOSAKI Motohiro if (end < vma->vm_end && mm->map_count >= sysctl_max_map_count) 2389d4af56c5SLiam R. Howlett goto map_count_exceeded; 2390659ace58SKOSAKI Motohiro 23910c0c5bffSLiam R. Howlett error = vmi__split_vma(vmi, mm, vma, start, 0); 23921da177e4SLinus Torvalds if (error) 2393763ecb03SLiam R. Howlett goto start_split_failed; 239411f9a21aSLiam R. Howlett 2395183654ceSLiam R. Howlett vma_iter_set(vmi, start); 2396183654ceSLiam R. Howlett vma = vma_find(vmi, end); 23971da177e4SLinus Torvalds } 23981da177e4SLinus Torvalds 2399183654ceSLiam R. Howlett prev = vma_prev(vmi); 2400763ecb03SLiam R. Howlett if (unlikely((!prev))) 2401183654ceSLiam R. Howlett vma_iter_set(vmi, start); 240211f9a21aSLiam R. Howlett 2403763ecb03SLiam R. Howlett /* 2404763ecb03SLiam R. Howlett * Detach a range of VMAs from the mm. Using next as a temp variable as 2405763ecb03SLiam R. Howlett * it is always overwritten. 2406763ecb03SLiam R. Howlett */ 2407183654ceSLiam R. Howlett for_each_vma_range(*vmi, next, end) { 2408763ecb03SLiam R. Howlett /* Does it split the end? */ 2409763ecb03SLiam R. Howlett if (next->vm_end > end) { 2410763ecb03SLiam R. Howlett struct vm_area_struct *split; 241111f9a21aSLiam R. Howlett 24120c0c5bffSLiam R. Howlett error = vmi__split_vma(vmi, mm, next, end, 1); 24131da177e4SLinus Torvalds if (error) 2414763ecb03SLiam R. Howlett goto end_split_failed; 241511f9a21aSLiam R. Howlett 2416183654ceSLiam R. Howlett vma_iter_set(vmi, end); 2417183654ceSLiam R. Howlett split = vma_prev(vmi); 2418763ecb03SLiam R. Howlett error = munmap_sidetree(split, &mas_detach); 2419763ecb03SLiam R. Howlett if (error) 2420763ecb03SLiam R. Howlett goto munmap_sidetree_failed; 2421763ecb03SLiam R. Howlett 2422763ecb03SLiam R. Howlett count++; 2423763ecb03SLiam R. Howlett if (vma == next) 2424763ecb03SLiam R. Howlett vma = split; 2425763ecb03SLiam R. Howlett break; 242611f9a21aSLiam R. Howlett } 2427763ecb03SLiam R. Howlett error = munmap_sidetree(next, &mas_detach); 2428763ecb03SLiam R. Howlett if (error) 2429763ecb03SLiam R. Howlett goto munmap_sidetree_failed; 2430763ecb03SLiam R. Howlett 2431763ecb03SLiam R. Howlett count++; 2432763ecb03SLiam R. Howlett #ifdef CONFIG_DEBUG_VM_MAPLE_TREE 2433763ecb03SLiam R. Howlett BUG_ON(next->vm_start < start); 2434763ecb03SLiam R. Howlett BUG_ON(next->vm_start > end); 2435763ecb03SLiam R. Howlett #endif 2436763ecb03SLiam R. Howlett } 2437763ecb03SLiam R. Howlett 2438763ecb03SLiam R. Howlett if (!next) 2439183654ceSLiam R. Howlett next = vma_next(vmi); 24401da177e4SLinus Torvalds 24412376dd7cSAndrea Arcangeli if (unlikely(uf)) { 24422376dd7cSAndrea Arcangeli /* 24432376dd7cSAndrea Arcangeli * If userfaultfd_unmap_prep returns an error the vmas 2444f0953a1bSIngo Molnar * will remain split, but userland will get a 24452376dd7cSAndrea Arcangeli * highly unexpected error anyway. This is no 24462376dd7cSAndrea Arcangeli * different than the case where the first of the two 24472376dd7cSAndrea Arcangeli * __split_vma fails, but we don't undo the first 24482376dd7cSAndrea Arcangeli * split, despite we could. This is unlikely enough 24492376dd7cSAndrea Arcangeli * failure that it's not worth optimizing it for. 24502376dd7cSAndrea Arcangeli */ 245169dbe6daSLiam R. Howlett error = userfaultfd_unmap_prep(mm, start, end, uf); 245211f9a21aSLiam R. Howlett 24532376dd7cSAndrea Arcangeli if (error) 2454d4af56c5SLiam R. Howlett goto userfaultfd_error; 24552376dd7cSAndrea Arcangeli } 24562376dd7cSAndrea Arcangeli 2457763ecb03SLiam R. Howlett #if defined(CONFIG_DEBUG_VM_MAPLE_TREE) 2458763ecb03SLiam R. Howlett /* Make sure no VMAs are about to be lost. */ 2459763ecb03SLiam R. Howlett { 2460763ecb03SLiam R. Howlett MA_STATE(test, &mt_detach, start, end - 1); 2461763ecb03SLiam R. Howlett struct vm_area_struct *vma_mas, *vma_test; 2462763ecb03SLiam R. Howlett int test_count = 0; 2463763ecb03SLiam R. Howlett 2464183654ceSLiam R. Howlett vma_iter_set(vmi, start); 2465763ecb03SLiam R. Howlett rcu_read_lock(); 2466763ecb03SLiam R. Howlett vma_test = mas_find(&test, end - 1); 2467183654ceSLiam R. Howlett for_each_vma_range(*vmi, vma_mas, end) { 2468763ecb03SLiam R. Howlett BUG_ON(vma_mas != vma_test); 2469763ecb03SLiam R. Howlett test_count++; 2470763ecb03SLiam R. Howlett vma_test = mas_next(&test, end - 1); 2471763ecb03SLiam R. Howlett } 2472763ecb03SLiam R. Howlett rcu_read_unlock(); 2473763ecb03SLiam R. Howlett BUG_ON(count != test_count); 2474763ecb03SLiam R. Howlett } 2475763ecb03SLiam R. Howlett #endif 24760378c0a0SLiam R. Howlett /* Point of no return */ 2477183654ceSLiam R. Howlett vma_iter_set(vmi, start); 2478183654ceSLiam R. Howlett if (vma_iter_clear_gfp(vmi, start, end, GFP_KERNEL)) 24790378c0a0SLiam R. Howlett return -ENOMEM; 24800378c0a0SLiam R. Howlett 2481763ecb03SLiam R. Howlett mm->map_count -= count; 248211f9a21aSLiam R. Howlett /* 248311f9a21aSLiam R. Howlett * Do not downgrade mmap_lock if we are next to VM_GROWSDOWN or 248411f9a21aSLiam R. Howlett * VM_GROWSUP VMA. Such VMAs can change their size under 248511f9a21aSLiam R. Howlett * down_read(mmap_lock) and collide with the VMA we are about to unmap. 248611f9a21aSLiam R. Howlett */ 248711f9a21aSLiam R. Howlett if (downgrade) { 2488763ecb03SLiam R. Howlett if (next && (next->vm_flags & VM_GROWSDOWN)) 248911f9a21aSLiam R. Howlett downgrade = false; 249011f9a21aSLiam R. Howlett else if (prev && (prev->vm_flags & VM_GROWSUP)) 249111f9a21aSLiam R. Howlett downgrade = false; 249211f9a21aSLiam R. Howlett else 2493d8ed45c5SMichel Lespinasse mmap_write_downgrade(mm); 249411f9a21aSLiam R. Howlett } 2495dd2283f2SYang Shi 2496763ecb03SLiam R. Howlett unmap_region(mm, &mt_detach, vma, prev, next, start, end); 2497763ecb03SLiam R. Howlett /* Statistics and freeing VMAs */ 2498763ecb03SLiam R. Howlett mas_set(&mas_detach, start); 2499763ecb03SLiam R. Howlett remove_mt(mm, &mas_detach); 2500763ecb03SLiam R. Howlett __mt_destroy(&mt_detach); 25011da177e4SLinus Torvalds 2502524e00b3SLiam R. Howlett 2503524e00b3SLiam R. Howlett validate_mm(mm); 2504dd2283f2SYang Shi return downgrade ? 1 : 0; 2505d4af56c5SLiam R. Howlett 2506d4af56c5SLiam R. Howlett userfaultfd_error: 2507763ecb03SLiam R. Howlett munmap_sidetree_failed: 2508763ecb03SLiam R. Howlett end_split_failed: 2509763ecb03SLiam R. Howlett __mt_destroy(&mt_detach); 2510763ecb03SLiam R. Howlett start_split_failed: 2511763ecb03SLiam R. Howlett map_count_exceeded: 2512d4af56c5SLiam R. Howlett return error; 25131da177e4SLinus Torvalds } 25141da177e4SLinus Torvalds 251511f9a21aSLiam R. Howlett /* 2516183654ceSLiam R. Howlett * do_vmi_munmap() - munmap a given range. 2517183654ceSLiam R. Howlett * @vmi: The vma iterator 251811f9a21aSLiam R. Howlett * @mm: The mm_struct 251911f9a21aSLiam R. Howlett * @start: The start address to munmap 252011f9a21aSLiam R. Howlett * @len: The length of the range to munmap 252111f9a21aSLiam R. Howlett * @uf: The userfaultfd list_head 252211f9a21aSLiam R. Howlett * @downgrade: set to true if the user wants to attempt to write_downgrade the 25238651a137SLorenzo Stoakes * mmap_lock 252411f9a21aSLiam R. Howlett * 252511f9a21aSLiam R. Howlett * This function takes a @mas that is either pointing to the previous VMA or set 252611f9a21aSLiam R. Howlett * to MA_START and sets it up to remove the mapping(s). The @len will be 252711f9a21aSLiam R. Howlett * aligned and any arch_unmap work will be preformed. 252811f9a21aSLiam R. Howlett * 252911f9a21aSLiam R. Howlett * Returns: -EINVAL on failure, 1 on success and unlock, 0 otherwise. 253011f9a21aSLiam R. Howlett */ 2531183654ceSLiam R. Howlett int do_vmi_munmap(struct vma_iterator *vmi, struct mm_struct *mm, 253211f9a21aSLiam R. Howlett unsigned long start, size_t len, struct list_head *uf, 253311f9a21aSLiam R. Howlett bool downgrade) 253411f9a21aSLiam R. Howlett { 253511f9a21aSLiam R. Howlett unsigned long end; 253611f9a21aSLiam R. Howlett struct vm_area_struct *vma; 253711f9a21aSLiam R. Howlett 253811f9a21aSLiam R. Howlett if ((offset_in_page(start)) || start > TASK_SIZE || len > TASK_SIZE-start) 253911f9a21aSLiam R. Howlett return -EINVAL; 254011f9a21aSLiam R. Howlett 254111f9a21aSLiam R. Howlett end = start + PAGE_ALIGN(len); 254211f9a21aSLiam R. Howlett if (end == start) 254311f9a21aSLiam R. Howlett return -EINVAL; 254411f9a21aSLiam R. Howlett 254511f9a21aSLiam R. Howlett /* arch_unmap() might do unmaps itself. */ 254611f9a21aSLiam R. Howlett arch_unmap(mm, start, end); 254711f9a21aSLiam R. Howlett 254811f9a21aSLiam R. Howlett /* Find the first overlapping VMA */ 2549183654ceSLiam R. Howlett vma = vma_find(vmi, end); 255011f9a21aSLiam R. Howlett if (!vma) 255111f9a21aSLiam R. Howlett return 0; 255211f9a21aSLiam R. Howlett 2553183654ceSLiam R. Howlett return do_vmi_align_munmap(vmi, vma, mm, start, end, uf, downgrade); 255411f9a21aSLiam R. Howlett } 255511f9a21aSLiam R. Howlett 255611f9a21aSLiam R. Howlett /* do_munmap() - Wrapper function for non-maple tree aware do_munmap() calls. 255711f9a21aSLiam R. Howlett * @mm: The mm_struct 255811f9a21aSLiam R. Howlett * @start: The start address to munmap 255911f9a21aSLiam R. Howlett * @len: The length to be munmapped. 256011f9a21aSLiam R. Howlett * @uf: The userfaultfd list_head 256111f9a21aSLiam R. Howlett */ 2562dd2283f2SYang Shi int do_munmap(struct mm_struct *mm, unsigned long start, size_t len, 2563dd2283f2SYang Shi struct list_head *uf) 2564dd2283f2SYang Shi { 2565183654ceSLiam R. Howlett VMA_ITERATOR(vmi, mm, start); 256611f9a21aSLiam R. Howlett 2567183654ceSLiam R. Howlett return do_vmi_munmap(&vmi, mm, start, len, uf, false); 2568dd2283f2SYang Shi } 2569dd2283f2SYang Shi 2570e99668a5SLiam R. Howlett unsigned long mmap_region(struct file *file, unsigned long addr, 2571e99668a5SLiam R. Howlett unsigned long len, vm_flags_t vm_flags, unsigned long pgoff, 2572e99668a5SLiam R. Howlett struct list_head *uf) 2573e99668a5SLiam R. Howlett { 2574e99668a5SLiam R. Howlett struct mm_struct *mm = current->mm; 2575e99668a5SLiam R. Howlett struct vm_area_struct *vma = NULL; 2576e99668a5SLiam R. Howlett struct vm_area_struct *next, *prev, *merge; 2577e99668a5SLiam R. Howlett pgoff_t pglen = len >> PAGE_SHIFT; 2578e99668a5SLiam R. Howlett unsigned long charged = 0; 2579e99668a5SLiam R. Howlett unsigned long end = addr + len; 2580e99668a5SLiam R. Howlett unsigned long merge_start = addr, merge_end = end; 2581e99668a5SLiam R. Howlett pgoff_t vm_pgoff; 2582e99668a5SLiam R. Howlett int error; 2583183654ceSLiam R. Howlett VMA_ITERATOR(vmi, mm, addr); 2584e99668a5SLiam R. Howlett 2585e99668a5SLiam R. Howlett /* Check against address space limit. */ 2586e99668a5SLiam R. Howlett if (!may_expand_vm(mm, vm_flags, len >> PAGE_SHIFT)) { 2587e99668a5SLiam R. Howlett unsigned long nr_pages; 2588e99668a5SLiam R. Howlett 2589e99668a5SLiam R. Howlett /* 2590e99668a5SLiam R. Howlett * MAP_FIXED may remove pages of mappings that intersects with 2591e99668a5SLiam R. Howlett * requested mapping. Account for the pages it would unmap. 2592e99668a5SLiam R. Howlett */ 2593e99668a5SLiam R. Howlett nr_pages = count_vma_pages_range(mm, addr, end); 2594e99668a5SLiam R. Howlett 2595e99668a5SLiam R. Howlett if (!may_expand_vm(mm, vm_flags, 2596e99668a5SLiam R. Howlett (len >> PAGE_SHIFT) - nr_pages)) 2597e99668a5SLiam R. Howlett return -ENOMEM; 2598e99668a5SLiam R. Howlett } 2599e99668a5SLiam R. Howlett 2600e99668a5SLiam R. Howlett /* Unmap any existing mapping in the area */ 2601183654ceSLiam R. Howlett if (do_vmi_munmap(&vmi, mm, addr, len, uf, false)) 2602e99668a5SLiam R. Howlett return -ENOMEM; 2603e99668a5SLiam R. Howlett 2604e99668a5SLiam R. Howlett /* 2605e99668a5SLiam R. Howlett * Private writable mapping: check memory availability 2606e99668a5SLiam R. Howlett */ 2607e99668a5SLiam R. Howlett if (accountable_mapping(file, vm_flags)) { 2608e99668a5SLiam R. Howlett charged = len >> PAGE_SHIFT; 2609e99668a5SLiam R. Howlett if (security_vm_enough_memory_mm(mm, charged)) 2610e99668a5SLiam R. Howlett return -ENOMEM; 2611e99668a5SLiam R. Howlett vm_flags |= VM_ACCOUNT; 2612e99668a5SLiam R. Howlett } 2613e99668a5SLiam R. Howlett 2614183654ceSLiam R. Howlett next = vma_next(&vmi); 2615183654ceSLiam R. Howlett prev = vma_prev(&vmi); 2616e99668a5SLiam R. Howlett if (vm_flags & VM_SPECIAL) 2617e99668a5SLiam R. Howlett goto cannot_expand; 2618e99668a5SLiam R. Howlett 2619e99668a5SLiam R. Howlett /* Attempt to expand an old mapping */ 2620e99668a5SLiam R. Howlett /* Check next */ 2621e99668a5SLiam R. Howlett if (next && next->vm_start == end && !vma_policy(next) && 2622e99668a5SLiam R. Howlett can_vma_merge_before(next, vm_flags, NULL, file, pgoff+pglen, 2623e99668a5SLiam R. Howlett NULL_VM_UFFD_CTX, NULL)) { 2624e99668a5SLiam R. Howlett merge_end = next->vm_end; 2625e99668a5SLiam R. Howlett vma = next; 2626e99668a5SLiam R. Howlett vm_pgoff = next->vm_pgoff - pglen; 2627e99668a5SLiam R. Howlett } 2628e99668a5SLiam R. Howlett 2629e99668a5SLiam R. Howlett /* Check prev */ 2630e99668a5SLiam R. Howlett if (prev && prev->vm_end == addr && !vma_policy(prev) && 2631e99668a5SLiam R. Howlett (vma ? can_vma_merge_after(prev, vm_flags, vma->anon_vma, file, 2632e99668a5SLiam R. Howlett pgoff, vma->vm_userfaultfd_ctx, NULL) : 2633e99668a5SLiam R. Howlett can_vma_merge_after(prev, vm_flags, NULL, file, pgoff, 2634e99668a5SLiam R. Howlett NULL_VM_UFFD_CTX, NULL))) { 2635e99668a5SLiam R. Howlett merge_start = prev->vm_start; 2636e99668a5SLiam R. Howlett vma = prev; 2637e99668a5SLiam R. Howlett vm_pgoff = prev->vm_pgoff; 2638e99668a5SLiam R. Howlett } 2639e99668a5SLiam R. Howlett 2640e99668a5SLiam R. Howlett 2641e99668a5SLiam R. Howlett /* Actually expand, if possible */ 2642e99668a5SLiam R. Howlett if (vma && 26433c441ab7SLiam R. Howlett !vma_expand(&vmi, vma, merge_start, merge_end, vm_pgoff, next)) { 2644e99668a5SLiam R. Howlett khugepaged_enter_vma(vma, vm_flags); 2645e99668a5SLiam R. Howlett goto expanded; 2646e99668a5SLiam R. Howlett } 2647e99668a5SLiam R. Howlett 2648e99668a5SLiam R. Howlett cannot_expand: 2649e99668a5SLiam R. Howlett /* 2650e99668a5SLiam R. Howlett * Determine the object being mapped and call the appropriate 2651e99668a5SLiam R. Howlett * specific mapper. the address has already been validated, but 2652e99668a5SLiam R. Howlett * not unmapped, but the maps are removed from the list. 2653e99668a5SLiam R. Howlett */ 2654e99668a5SLiam R. Howlett vma = vm_area_alloc(mm); 2655e99668a5SLiam R. Howlett if (!vma) { 2656e99668a5SLiam R. Howlett error = -ENOMEM; 2657e99668a5SLiam R. Howlett goto unacct_error; 2658e99668a5SLiam R. Howlett } 2659e99668a5SLiam R. Howlett 2660e99668a5SLiam R. Howlett vma->vm_start = addr; 2661e99668a5SLiam R. Howlett vma->vm_end = end; 2662e99668a5SLiam R. Howlett vma->vm_flags = vm_flags; 2663e99668a5SLiam R. Howlett vma->vm_page_prot = vm_get_page_prot(vm_flags); 2664e99668a5SLiam R. Howlett vma->vm_pgoff = pgoff; 2665e99668a5SLiam R. Howlett 2666e99668a5SLiam R. Howlett if (file) { 2667e99668a5SLiam R. Howlett if (vm_flags & VM_SHARED) { 2668e99668a5SLiam R. Howlett error = mapping_map_writable(file->f_mapping); 2669e99668a5SLiam R. Howlett if (error) 2670e99668a5SLiam R. Howlett goto free_vma; 2671e99668a5SLiam R. Howlett } 2672e99668a5SLiam R. Howlett 2673e99668a5SLiam R. Howlett vma->vm_file = get_file(file); 2674e99668a5SLiam R. Howlett error = call_mmap(file, vma); 2675e99668a5SLiam R. Howlett if (error) 2676e99668a5SLiam R. Howlett goto unmap_and_free_vma; 2677e99668a5SLiam R. Howlett 2678a57b7051SLiam Howlett /* 2679a57b7051SLiam Howlett * Expansion is handled above, merging is handled below. 2680a57b7051SLiam Howlett * Drivers should not alter the address of the VMA. 2681e99668a5SLiam R. Howlett */ 2682a57b7051SLiam Howlett if (WARN_ON((addr != vma->vm_start))) { 2683a57b7051SLiam Howlett error = -EINVAL; 2684a57b7051SLiam Howlett goto close_and_free_vma; 2685a57b7051SLiam Howlett } 2686183654ceSLiam R. Howlett vma_iter_set(&vmi, addr); 2687e99668a5SLiam R. Howlett 2688e99668a5SLiam R. Howlett /* 2689e99668a5SLiam R. Howlett * If vm_flags changed after call_mmap(), we should try merge 2690e99668a5SLiam R. Howlett * vma again as we may succeed this time. 2691e99668a5SLiam R. Howlett */ 2692e99668a5SLiam R. Howlett if (unlikely(vm_flags != vma->vm_flags && prev)) { 2693*076f16bfSLiam R. Howlett merge = vmi_vma_merge(&vmi, mm, prev, vma->vm_start, 2694*076f16bfSLiam R. Howlett vma->vm_end, vma->vm_flags, NULL, vma->vm_file, 2695*076f16bfSLiam R. Howlett vma->vm_pgoff, NULL, NULL_VM_UFFD_CTX, NULL); 2696e99668a5SLiam R. Howlett if (merge) { 2697e99668a5SLiam R. Howlett /* 2698e99668a5SLiam R. Howlett * ->mmap() can change vma->vm_file and fput 2699e99668a5SLiam R. Howlett * the original file. So fput the vma->vm_file 2700e99668a5SLiam R. Howlett * here or we would add an extra fput for file 2701e99668a5SLiam R. Howlett * and cause general protection fault 2702e99668a5SLiam R. Howlett * ultimately. 2703e99668a5SLiam R. Howlett */ 2704e99668a5SLiam R. Howlett fput(vma->vm_file); 2705e99668a5SLiam R. Howlett vm_area_free(vma); 2706e99668a5SLiam R. Howlett vma = merge; 2707e99668a5SLiam R. Howlett /* Update vm_flags to pick up the change. */ 2708e99668a5SLiam R. Howlett vm_flags = vma->vm_flags; 2709e99668a5SLiam R. Howlett goto unmap_writable; 2710e99668a5SLiam R. Howlett } 2711e99668a5SLiam R. Howlett } 2712e99668a5SLiam R. Howlett 2713e99668a5SLiam R. Howlett vm_flags = vma->vm_flags; 2714e99668a5SLiam R. Howlett } else if (vm_flags & VM_SHARED) { 2715e99668a5SLiam R. Howlett error = shmem_zero_setup(vma); 2716e99668a5SLiam R. Howlett if (error) 2717e99668a5SLiam R. Howlett goto free_vma; 2718e99668a5SLiam R. Howlett } else { 2719e99668a5SLiam R. Howlett vma_set_anonymous(vma); 2720e99668a5SLiam R. Howlett } 2721e99668a5SLiam R. Howlett 2722b507808eSJoey Gouly if (map_deny_write_exec(vma, vma->vm_flags)) { 2723b507808eSJoey Gouly error = -EACCES; 2724b507808eSJoey Gouly if (file) 2725b507808eSJoey Gouly goto close_and_free_vma; 2726b507808eSJoey Gouly else if (vma->vm_file) 2727b507808eSJoey Gouly goto unmap_and_free_vma; 2728b507808eSJoey Gouly else 2729b507808eSJoey Gouly goto free_vma; 2730b507808eSJoey Gouly } 2731b507808eSJoey Gouly 2732e99668a5SLiam R. Howlett /* Allow architectures to sanity-check the vm_flags */ 2733e99668a5SLiam R. Howlett if (!arch_validate_flags(vma->vm_flags)) { 2734e99668a5SLiam R. Howlett error = -EINVAL; 2735e99668a5SLiam R. Howlett if (file) 2736deb0f656SCarlos Llamas goto close_and_free_vma; 2737cc674ab3SLi Zetao else if (vma->vm_file) 2738cc674ab3SLi Zetao goto unmap_and_free_vma; 2739e99668a5SLiam R. Howlett else 2740e99668a5SLiam R. Howlett goto free_vma; 2741e99668a5SLiam R. Howlett } 2742e99668a5SLiam R. Howlett 2743183654ceSLiam R. Howlett if (vma_iter_prealloc(&vmi)) { 2744e99668a5SLiam R. Howlett error = -ENOMEM; 2745e99668a5SLiam R. Howlett if (file) 27465789151eSMike Kravetz goto close_and_free_vma; 2747cc674ab3SLi Zetao else if (vma->vm_file) 2748cc674ab3SLi Zetao goto unmap_and_free_vma; 2749e99668a5SLiam R. Howlett else 2750e99668a5SLiam R. Howlett goto free_vma; 2751e99668a5SLiam R. Howlett } 2752e99668a5SLiam R. Howlett 2753e99668a5SLiam R. Howlett if (vma->vm_file) 2754e99668a5SLiam R. Howlett i_mmap_lock_write(vma->vm_file->f_mapping); 2755e99668a5SLiam R. Howlett 2756183654ceSLiam R. Howlett vma_iter_store(&vmi, vma); 2757e99668a5SLiam R. Howlett mm->map_count++; 2758e99668a5SLiam R. Howlett if (vma->vm_file) { 2759e99668a5SLiam R. Howlett if (vma->vm_flags & VM_SHARED) 2760e99668a5SLiam R. Howlett mapping_allow_writable(vma->vm_file->f_mapping); 2761e99668a5SLiam R. Howlett 2762e99668a5SLiam R. Howlett flush_dcache_mmap_lock(vma->vm_file->f_mapping); 2763e99668a5SLiam R. Howlett vma_interval_tree_insert(vma, &vma->vm_file->f_mapping->i_mmap); 2764e99668a5SLiam R. Howlett flush_dcache_mmap_unlock(vma->vm_file->f_mapping); 2765e99668a5SLiam R. Howlett i_mmap_unlock_write(vma->vm_file->f_mapping); 2766e99668a5SLiam R. Howlett } 2767e99668a5SLiam R. Howlett 2768e99668a5SLiam R. Howlett /* 2769e99668a5SLiam R. Howlett * vma_merge() calls khugepaged_enter_vma() either, the below 2770e99668a5SLiam R. Howlett * call covers the non-merge case. 2771e99668a5SLiam R. Howlett */ 2772e99668a5SLiam R. Howlett khugepaged_enter_vma(vma, vma->vm_flags); 2773e99668a5SLiam R. Howlett 2774e99668a5SLiam R. Howlett /* Once vma denies write, undo our temporary denial count */ 2775e99668a5SLiam R. Howlett unmap_writable: 2776e99668a5SLiam R. Howlett if (file && vm_flags & VM_SHARED) 2777e99668a5SLiam R. Howlett mapping_unmap_writable(file->f_mapping); 2778e99668a5SLiam R. Howlett file = vma->vm_file; 2779e99668a5SLiam R. Howlett expanded: 2780e99668a5SLiam R. Howlett perf_event_mmap(vma); 2781e99668a5SLiam R. Howlett 2782e99668a5SLiam R. Howlett vm_stat_account(mm, vm_flags, len >> PAGE_SHIFT); 2783e99668a5SLiam R. Howlett if (vm_flags & VM_LOCKED) { 2784e99668a5SLiam R. Howlett if ((vm_flags & VM_SPECIAL) || vma_is_dax(vma) || 2785e99668a5SLiam R. Howlett is_vm_hugetlb_page(vma) || 2786e99668a5SLiam R. Howlett vma == get_gate_vma(current->mm)) 2787e99668a5SLiam R. Howlett vma->vm_flags &= VM_LOCKED_CLEAR_MASK; 2788e99668a5SLiam R. Howlett else 2789e99668a5SLiam R. Howlett mm->locked_vm += (len >> PAGE_SHIFT); 2790e99668a5SLiam R. Howlett } 2791e99668a5SLiam R. Howlett 2792e99668a5SLiam R. Howlett if (file) 2793e99668a5SLiam R. Howlett uprobe_mmap(vma); 2794e99668a5SLiam R. Howlett 2795e99668a5SLiam R. Howlett /* 2796e99668a5SLiam R. Howlett * New (or expanded) vma always get soft dirty status. 2797e99668a5SLiam R. Howlett * Otherwise user-space soft-dirty page tracker won't 2798e99668a5SLiam R. Howlett * be able to distinguish situation when vma area unmapped, 2799e99668a5SLiam R. Howlett * then new mapped in-place (which must be aimed as 2800e99668a5SLiam R. Howlett * a completely new data area). 2801e99668a5SLiam R. Howlett */ 2802e99668a5SLiam R. Howlett vma->vm_flags |= VM_SOFTDIRTY; 2803e99668a5SLiam R. Howlett 2804e99668a5SLiam R. Howlett vma_set_page_prot(vma); 2805e99668a5SLiam R. Howlett 2806e99668a5SLiam R. Howlett validate_mm(mm); 2807e99668a5SLiam R. Howlett return addr; 2808e99668a5SLiam R. Howlett 2809deb0f656SCarlos Llamas close_and_free_vma: 2810deb0f656SCarlos Llamas if (vma->vm_ops && vma->vm_ops->close) 2811deb0f656SCarlos Llamas vma->vm_ops->close(vma); 2812e99668a5SLiam R. Howlett unmap_and_free_vma: 2813e99668a5SLiam R. Howlett fput(vma->vm_file); 2814e99668a5SLiam R. Howlett vma->vm_file = NULL; 2815e99668a5SLiam R. Howlett 2816e99668a5SLiam R. Howlett /* Undo any partial mapping done by a device driver. */ 2817183654ceSLiam R. Howlett unmap_region(mm, &mm->mm_mt, vma, prev, next, vma->vm_start, vma->vm_end); 2818cc674ab3SLi Zetao if (file && (vm_flags & VM_SHARED)) 2819e99668a5SLiam R. Howlett mapping_unmap_writable(file->f_mapping); 2820e99668a5SLiam R. Howlett free_vma: 2821e99668a5SLiam R. Howlett vm_area_free(vma); 2822e99668a5SLiam R. Howlett unacct_error: 2823e99668a5SLiam R. Howlett if (charged) 2824e99668a5SLiam R. Howlett vm_unacct_memory(charged); 2825e99668a5SLiam R. Howlett validate_mm(mm); 2826e99668a5SLiam R. Howlett return error; 2827e99668a5SLiam R. Howlett } 2828e99668a5SLiam R. Howlett 2829dd2283f2SYang Shi static int __vm_munmap(unsigned long start, size_t len, bool downgrade) 2830a46ef99dSLinus Torvalds { 2831a46ef99dSLinus Torvalds int ret; 2832bfce281cSAl Viro struct mm_struct *mm = current->mm; 2833897ab3e0SMike Rapoport LIST_HEAD(uf); 2834183654ceSLiam R. Howlett VMA_ITERATOR(vmi, mm, start); 2835a46ef99dSLinus Torvalds 2836d8ed45c5SMichel Lespinasse if (mmap_write_lock_killable(mm)) 2837ae798783SMichal Hocko return -EINTR; 2838ae798783SMichal Hocko 2839183654ceSLiam R. Howlett ret = do_vmi_munmap(&vmi, mm, start, len, &uf, downgrade); 2840dd2283f2SYang Shi /* 2841c1e8d7c6SMichel Lespinasse * Returning 1 indicates mmap_lock is downgraded. 2842dd2283f2SYang Shi * But 1 is not legal return value of vm_munmap() and munmap(), reset 2843dd2283f2SYang Shi * it to 0 before return. 2844dd2283f2SYang Shi */ 2845dd2283f2SYang Shi if (ret == 1) { 2846d8ed45c5SMichel Lespinasse mmap_read_unlock(mm); 2847dd2283f2SYang Shi ret = 0; 2848dd2283f2SYang Shi } else 2849d8ed45c5SMichel Lespinasse mmap_write_unlock(mm); 2850dd2283f2SYang Shi 2851897ab3e0SMike Rapoport userfaultfd_unmap_complete(mm, &uf); 2852a46ef99dSLinus Torvalds return ret; 2853a46ef99dSLinus Torvalds } 2854dd2283f2SYang Shi 2855dd2283f2SYang Shi int vm_munmap(unsigned long start, size_t len) 2856dd2283f2SYang Shi { 2857dd2283f2SYang Shi return __vm_munmap(start, len, false); 2858dd2283f2SYang Shi } 2859a46ef99dSLinus Torvalds EXPORT_SYMBOL(vm_munmap); 2860a46ef99dSLinus Torvalds 28616a6160a7SHeiko Carstens SYSCALL_DEFINE2(munmap, unsigned long, addr, size_t, len) 28621da177e4SLinus Torvalds { 2863ce18d171SCatalin Marinas addr = untagged_addr(addr); 2864dd2283f2SYang Shi return __vm_munmap(addr, len, true); 28651da177e4SLinus Torvalds } 28661da177e4SLinus Torvalds 2867c8d78c18SKirill A. Shutemov 2868c8d78c18SKirill A. Shutemov /* 2869c8d78c18SKirill A. Shutemov * Emulation of deprecated remap_file_pages() syscall. 2870c8d78c18SKirill A. Shutemov */ 2871c8d78c18SKirill A. Shutemov SYSCALL_DEFINE5(remap_file_pages, unsigned long, start, unsigned long, size, 2872c8d78c18SKirill A. Shutemov unsigned long, prot, unsigned long, pgoff, unsigned long, flags) 2873c8d78c18SKirill A. Shutemov { 2874c8d78c18SKirill A. Shutemov 2875c8d78c18SKirill A. Shutemov struct mm_struct *mm = current->mm; 2876c8d78c18SKirill A. Shutemov struct vm_area_struct *vma; 2877c8d78c18SKirill A. Shutemov unsigned long populate = 0; 2878c8d78c18SKirill A. Shutemov unsigned long ret = -EINVAL; 2879c8d78c18SKirill A. Shutemov struct file *file; 2880c8d78c18SKirill A. Shutemov 2881ee65728eSMike Rapoport pr_warn_once("%s (%d) uses deprecated remap_file_pages() syscall. See Documentation/mm/remap_file_pages.rst.\n", 2882c8d78c18SKirill A. Shutemov current->comm, current->pid); 2883c8d78c18SKirill A. Shutemov 2884c8d78c18SKirill A. Shutemov if (prot) 2885c8d78c18SKirill A. Shutemov return ret; 2886c8d78c18SKirill A. Shutemov start = start & PAGE_MASK; 2887c8d78c18SKirill A. Shutemov size = size & PAGE_MASK; 2888c8d78c18SKirill A. Shutemov 2889c8d78c18SKirill A. Shutemov if (start + size <= start) 2890c8d78c18SKirill A. Shutemov return ret; 2891c8d78c18SKirill A. Shutemov 2892c8d78c18SKirill A. Shutemov /* Does pgoff wrap? */ 2893c8d78c18SKirill A. Shutemov if (pgoff + (size >> PAGE_SHIFT) < pgoff) 2894c8d78c18SKirill A. Shutemov return ret; 2895c8d78c18SKirill A. Shutemov 2896d8ed45c5SMichel Lespinasse if (mmap_write_lock_killable(mm)) 2897dc0ef0dfSMichal Hocko return -EINTR; 2898dc0ef0dfSMichal Hocko 28999b593cb2SLiam R. Howlett vma = vma_lookup(mm, start); 2900c8d78c18SKirill A. Shutemov 2901c8d78c18SKirill A. Shutemov if (!vma || !(vma->vm_flags & VM_SHARED)) 2902c8d78c18SKirill A. Shutemov goto out; 2903c8d78c18SKirill A. Shutemov 290448f7df32SKirill A. Shutemov if (start + size > vma->vm_end) { 2905763ecb03SLiam R. Howlett VMA_ITERATOR(vmi, mm, vma->vm_end); 2906763ecb03SLiam R. Howlett struct vm_area_struct *next, *prev = vma; 290748f7df32SKirill A. Shutemov 2908763ecb03SLiam R. Howlett for_each_vma_range(vmi, next, start + size) { 290948f7df32SKirill A. Shutemov /* hole between vmas ? */ 2910763ecb03SLiam R. Howlett if (next->vm_start != prev->vm_end) 291148f7df32SKirill A. Shutemov goto out; 291248f7df32SKirill A. Shutemov 291348f7df32SKirill A. Shutemov if (next->vm_file != vma->vm_file) 291448f7df32SKirill A. Shutemov goto out; 291548f7df32SKirill A. Shutemov 291648f7df32SKirill A. Shutemov if (next->vm_flags != vma->vm_flags) 291748f7df32SKirill A. Shutemov goto out; 291848f7df32SKirill A. Shutemov 29191db43d3fSLiam Howlett if (start + size <= next->vm_end) 29201db43d3fSLiam Howlett break; 29211db43d3fSLiam Howlett 2922763ecb03SLiam R. Howlett prev = next; 292348f7df32SKirill A. Shutemov } 292448f7df32SKirill A. Shutemov 292548f7df32SKirill A. Shutemov if (!next) 2926c8d78c18SKirill A. Shutemov goto out; 2927c8d78c18SKirill A. Shutemov } 2928c8d78c18SKirill A. Shutemov 2929c8d78c18SKirill A. Shutemov prot |= vma->vm_flags & VM_READ ? PROT_READ : 0; 2930c8d78c18SKirill A. Shutemov prot |= vma->vm_flags & VM_WRITE ? PROT_WRITE : 0; 2931c8d78c18SKirill A. Shutemov prot |= vma->vm_flags & VM_EXEC ? PROT_EXEC : 0; 2932c8d78c18SKirill A. Shutemov 2933c8d78c18SKirill A. Shutemov flags &= MAP_NONBLOCK; 2934c8d78c18SKirill A. Shutemov flags |= MAP_SHARED | MAP_FIXED | MAP_POPULATE; 2935fce000b1SLiam Howlett if (vma->vm_flags & VM_LOCKED) 2936c8d78c18SKirill A. Shutemov flags |= MAP_LOCKED; 293748f7df32SKirill A. Shutemov 2938c8d78c18SKirill A. Shutemov file = get_file(vma->vm_file); 293945e55300SPeter Collingbourne ret = do_mmap(vma->vm_file, start, size, 2940897ab3e0SMike Rapoport prot, flags, pgoff, &populate, NULL); 2941c8d78c18SKirill A. Shutemov fput(file); 2942c8d78c18SKirill A. Shutemov out: 2943d8ed45c5SMichel Lespinasse mmap_write_unlock(mm); 2944c8d78c18SKirill A. Shutemov if (populate) 2945c8d78c18SKirill A. Shutemov mm_populate(ret, populate); 2946c8d78c18SKirill A. Shutemov if (!IS_ERR_VALUE(ret)) 2947c8d78c18SKirill A. Shutemov ret = 0; 2948c8d78c18SKirill A. Shutemov return ret; 2949c8d78c18SKirill A. Shutemov } 2950c8d78c18SKirill A. Shutemov 29511da177e4SLinus Torvalds /* 295227b26701SLiam R. Howlett * do_vma_munmap() - Unmap a full or partial vma. 295327b26701SLiam R. Howlett * @vmi: The vma iterator pointing at the vma 295427b26701SLiam R. Howlett * @vma: The first vma to be munmapped 295527b26701SLiam R. Howlett * @start: the start of the address to unmap 295627b26701SLiam R. Howlett * @end: The end of the address to unmap 29572e7ce7d3SLiam R. Howlett * @uf: The userfaultfd list_head 295827b26701SLiam R. Howlett * @downgrade: Attempt to downgrade or not 29592e7ce7d3SLiam R. Howlett * 296027b26701SLiam R. Howlett * Returns: 0 on success and not downgraded, 1 on success and downgraded. 296127b26701SLiam R. Howlett * unmaps a VMA mapping when the vma iterator is already in position. 296227b26701SLiam R. Howlett * Does not handle alignment. 29631da177e4SLinus Torvalds */ 296427b26701SLiam R. Howlett int do_vma_munmap(struct vma_iterator *vmi, struct vm_area_struct *vma, 296527b26701SLiam R. Howlett unsigned long start, unsigned long end, 296627b26701SLiam R. Howlett struct list_head *uf, bool downgrade) 29672e7ce7d3SLiam R. Howlett { 29682e7ce7d3SLiam R. Howlett struct mm_struct *mm = vma->vm_mm; 29692e7ce7d3SLiam R. Howlett int ret; 29702e7ce7d3SLiam R. Howlett 297127b26701SLiam R. Howlett arch_unmap(mm, start, end); 297227b26701SLiam R. Howlett ret = do_vmi_align_munmap(vmi, vma, mm, start, end, uf, downgrade); 29732e7ce7d3SLiam R. Howlett validate_mm_mt(mm); 29742e7ce7d3SLiam R. Howlett return ret; 29752e7ce7d3SLiam R. Howlett } 29762e7ce7d3SLiam R. Howlett 29772e7ce7d3SLiam R. Howlett /* 29782e7ce7d3SLiam R. Howlett * do_brk_flags() - Increase the brk vma if the flags match. 297992fed820SLiam R. Howlett * @vmi: The vma iterator 29802e7ce7d3SLiam R. Howlett * @addr: The start address 29812e7ce7d3SLiam R. Howlett * @len: The length of the increase 29822e7ce7d3SLiam R. Howlett * @vma: The vma, 29832e7ce7d3SLiam R. Howlett * @flags: The VMA Flags 29842e7ce7d3SLiam R. Howlett * 29852e7ce7d3SLiam R. Howlett * Extend the brk VMA from addr to addr + len. If the VMA is NULL or the flags 29862e7ce7d3SLiam R. Howlett * do not match then create a new anonymous VMA. Eventually we may be able to 29872e7ce7d3SLiam R. Howlett * do some brk-specific accounting here. 29882e7ce7d3SLiam R. Howlett */ 298992fed820SLiam R. Howlett static int do_brk_flags(struct vma_iterator *vmi, struct vm_area_struct *vma, 2990763ecb03SLiam R. Howlett unsigned long addr, unsigned long len, unsigned long flags) 29911da177e4SLinus Torvalds { 29921da177e4SLinus Torvalds struct mm_struct *mm = current->mm; 29932e7ce7d3SLiam R. Howlett 2994d4af56c5SLiam R. Howlett validate_mm_mt(mm); 29952e7ce7d3SLiam R. Howlett /* 29962e7ce7d3SLiam R. Howlett * Check against address space limits by the changed size 29972e7ce7d3SLiam R. Howlett * Note: This happens *after* clearing old mappings in some code paths. 29982e7ce7d3SLiam R. Howlett */ 299916e72e9bSDenys Vlasenko flags |= VM_DATA_DEFAULT_FLAGS | VM_ACCOUNT | mm->def_flags; 300084638335SKonstantin Khlebnikov if (!may_expand_vm(mm, flags, len >> PAGE_SHIFT)) 30011da177e4SLinus Torvalds return -ENOMEM; 30021da177e4SLinus Torvalds 30031da177e4SLinus Torvalds if (mm->map_count > sysctl_max_map_count) 30041da177e4SLinus Torvalds return -ENOMEM; 30051da177e4SLinus Torvalds 3006191c5424SAl Viro if (security_vm_enough_memory_mm(mm, len >> PAGE_SHIFT)) 30071da177e4SLinus Torvalds return -ENOMEM; 30081da177e4SLinus Torvalds 30091da177e4SLinus Torvalds /* 30102e7ce7d3SLiam R. Howlett * Expand the existing vma if possible; Note that singular lists do not 30112e7ce7d3SLiam R. Howlett * occur after forking, so the expand will only happen on new VMAs. 30121da177e4SLinus Torvalds */ 30136c28ca64SLiam Howlett if (vma && vma->vm_end == addr && !vma_policy(vma) && 30146c28ca64SLiam Howlett can_vma_merge_after(vma, flags, NULL, NULL, 30156c28ca64SLiam Howlett addr >> PAGE_SHIFT, NULL_VM_UFFD_CTX, NULL)) { 301692fed820SLiam R. Howlett if (vma_iter_prealloc(vmi)) 3017675eaca1SAlistair Popple goto unacct_fail; 301828c5609fSLiam Howlett 301928c5609fSLiam Howlett vma_adjust_trans_huge(vma, vma->vm_start, addr + len, 0); 30202e7ce7d3SLiam R. Howlett if (vma->anon_vma) { 30212e7ce7d3SLiam R. Howlett anon_vma_lock_write(vma->anon_vma); 30222e7ce7d3SLiam R. Howlett anon_vma_interval_tree_pre_update_vma(vma); 30231da177e4SLinus Torvalds } 30242e7ce7d3SLiam R. Howlett vma->vm_end = addr + len; 30252e7ce7d3SLiam R. Howlett vma->vm_flags |= VM_SOFTDIRTY; 302692fed820SLiam R. Howlett vma_iter_store(vmi, vma); 30272e7ce7d3SLiam R. Howlett 30282e7ce7d3SLiam R. Howlett if (vma->anon_vma) { 30292e7ce7d3SLiam R. Howlett anon_vma_interval_tree_post_update_vma(vma); 30302e7ce7d3SLiam R. Howlett anon_vma_unlock_write(vma->anon_vma); 30312e7ce7d3SLiam R. Howlett } 30322e7ce7d3SLiam R. Howlett khugepaged_enter_vma(vma, flags); 30332e7ce7d3SLiam R. Howlett goto out; 30342e7ce7d3SLiam R. Howlett } 30352e7ce7d3SLiam R. Howlett 30362e7ce7d3SLiam R. Howlett /* create a vma struct for an anonymous mapping */ 30372e7ce7d3SLiam R. Howlett vma = vm_area_alloc(mm); 30382e7ce7d3SLiam R. Howlett if (!vma) 3039675eaca1SAlistair Popple goto unacct_fail; 30401da177e4SLinus Torvalds 3041bfd40eafSKirill A. Shutemov vma_set_anonymous(vma); 30421da177e4SLinus Torvalds vma->vm_start = addr; 30431da177e4SLinus Torvalds vma->vm_end = addr + len; 30442e7ce7d3SLiam R. Howlett vma->vm_pgoff = addr >> PAGE_SHIFT; 30451da177e4SLinus Torvalds vma->vm_flags = flags; 30463ed75eb8SColy Li vma->vm_page_prot = vm_get_page_prot(flags); 304792fed820SLiam R. Howlett if (vma_iter_store_gfp(vmi, vma, GFP_KERNEL)) 30482e7ce7d3SLiam R. Howlett goto mas_store_fail; 3049d4af56c5SLiam R. Howlett 30502e7ce7d3SLiam R. Howlett mm->map_count++; 30511da177e4SLinus Torvalds out: 30523af9e859SEric B Munson perf_event_mmap(vma); 30531da177e4SLinus Torvalds mm->total_vm += len >> PAGE_SHIFT; 305484638335SKonstantin Khlebnikov mm->data_vm += len >> PAGE_SHIFT; 3055128557ffSMichel Lespinasse if (flags & VM_LOCKED) 3056ba470de4SRik van Riel mm->locked_vm += (len >> PAGE_SHIFT); 3057d9104d1cSCyrill Gorcunov vma->vm_flags |= VM_SOFTDIRTY; 3058763ecb03SLiam R. Howlett validate_mm(mm); 30595d22fc25SLinus Torvalds return 0; 3060d4af56c5SLiam R. Howlett 30612e7ce7d3SLiam R. Howlett mas_store_fail: 3062d4af56c5SLiam R. Howlett vm_area_free(vma); 3063675eaca1SAlistair Popple unacct_fail: 30642e7ce7d3SLiam R. Howlett vm_unacct_memory(len >> PAGE_SHIFT); 30652e7ce7d3SLiam R. Howlett return -ENOMEM; 30661da177e4SLinus Torvalds } 30671da177e4SLinus Torvalds 3068bb177a73SMichal Hocko int vm_brk_flags(unsigned long addr, unsigned long request, unsigned long flags) 3069e4eb1ff6SLinus Torvalds { 3070e4eb1ff6SLinus Torvalds struct mm_struct *mm = current->mm; 30712e7ce7d3SLiam R. Howlett struct vm_area_struct *vma = NULL; 3072bb177a73SMichal Hocko unsigned long len; 30735d22fc25SLinus Torvalds int ret; 3074128557ffSMichel Lespinasse bool populate; 3075897ab3e0SMike Rapoport LIST_HEAD(uf); 307692fed820SLiam R. Howlett VMA_ITERATOR(vmi, mm, addr); 3077e4eb1ff6SLinus Torvalds 3078bb177a73SMichal Hocko len = PAGE_ALIGN(request); 3079bb177a73SMichal Hocko if (len < request) 3080bb177a73SMichal Hocko return -ENOMEM; 3081bb177a73SMichal Hocko if (!len) 3082bb177a73SMichal Hocko return 0; 3083bb177a73SMichal Hocko 3084d8ed45c5SMichel Lespinasse if (mmap_write_lock_killable(mm)) 30852d6c9282SMichal Hocko return -EINTR; 30862d6c9282SMichal Hocko 30872e7ce7d3SLiam R. Howlett /* Until we need other flags, refuse anything except VM_EXEC. */ 30882e7ce7d3SLiam R. Howlett if ((flags & (~VM_EXEC)) != 0) 30892e7ce7d3SLiam R. Howlett return -EINVAL; 30902e7ce7d3SLiam R. Howlett 30912e7ce7d3SLiam R. Howlett ret = check_brk_limits(addr, len); 30922e7ce7d3SLiam R. Howlett if (ret) 30932e7ce7d3SLiam R. Howlett goto limits_failed; 30942e7ce7d3SLiam R. Howlett 3095183654ceSLiam R. Howlett ret = do_vmi_munmap(&vmi, mm, addr, len, &uf, 0); 30962e7ce7d3SLiam R. Howlett if (ret) 30972e7ce7d3SLiam R. Howlett goto munmap_failed; 30982e7ce7d3SLiam R. Howlett 309992fed820SLiam R. Howlett vma = vma_prev(&vmi); 310092fed820SLiam R. Howlett ret = do_brk_flags(&vmi, vma, addr, len, flags); 3101128557ffSMichel Lespinasse populate = ((mm->def_flags & VM_LOCKED) != 0); 3102d8ed45c5SMichel Lespinasse mmap_write_unlock(mm); 3103897ab3e0SMike Rapoport userfaultfd_unmap_complete(mm, &uf); 31045d22fc25SLinus Torvalds if (populate && !ret) 3105128557ffSMichel Lespinasse mm_populate(addr, len); 3106e4eb1ff6SLinus Torvalds return ret; 31072e7ce7d3SLiam R. Howlett 31082e7ce7d3SLiam R. Howlett munmap_failed: 31092e7ce7d3SLiam R. Howlett limits_failed: 31102e7ce7d3SLiam R. Howlett mmap_write_unlock(mm); 31112e7ce7d3SLiam R. Howlett return ret; 3112e4eb1ff6SLinus Torvalds } 311316e72e9bSDenys Vlasenko EXPORT_SYMBOL(vm_brk_flags); 311416e72e9bSDenys Vlasenko 311516e72e9bSDenys Vlasenko int vm_brk(unsigned long addr, unsigned long len) 311616e72e9bSDenys Vlasenko { 311716e72e9bSDenys Vlasenko return vm_brk_flags(addr, len, 0); 311816e72e9bSDenys Vlasenko } 3119e4eb1ff6SLinus Torvalds EXPORT_SYMBOL(vm_brk); 31201da177e4SLinus Torvalds 31211da177e4SLinus Torvalds /* Release all mmaps. */ 31221da177e4SLinus Torvalds void exit_mmap(struct mm_struct *mm) 31231da177e4SLinus Torvalds { 3124d16dfc55SPeter Zijlstra struct mmu_gather tlb; 3125ba470de4SRik van Riel struct vm_area_struct *vma; 31261da177e4SLinus Torvalds unsigned long nr_accounted = 0; 3127763ecb03SLiam R. Howlett MA_STATE(mas, &mm->mm_mt, 0, 0); 3128763ecb03SLiam R. Howlett int count = 0; 31291da177e4SLinus Torvalds 3130d6dd61c8SJeremy Fitzhardinge /* mm's last user has gone, and its about to be pulled down */ 3131cddb8a5cSAndrea Arcangeli mmu_notifier_release(mm); 3132d6dd61c8SJeremy Fitzhardinge 3133bf3980c8SSuren Baghdasaryan mmap_read_lock(mm); 31349480c53eSJeremy Fitzhardinge arch_exit_mmap(mm); 31359480c53eSJeremy Fitzhardinge 3136763ecb03SLiam R. Howlett vma = mas_find(&mas, ULONG_MAX); 313764591e86SSuren Baghdasaryan if (!vma) { 313864591e86SSuren Baghdasaryan /* Can happen if dup_mmap() received an OOM */ 3139bf3980c8SSuren Baghdasaryan mmap_read_unlock(mm); 31409480c53eSJeremy Fitzhardinge return; 314164591e86SSuren Baghdasaryan } 31429480c53eSJeremy Fitzhardinge 31431da177e4SLinus Torvalds lru_add_drain(); 31441da177e4SLinus Torvalds flush_cache_mm(mm); 3145d8b45053SWill Deacon tlb_gather_mmu_fullmm(&tlb, mm); 3146901608d9SOleg Nesterov /* update_hiwater_rss(mm) here? but nobody should be looking */ 3147763ecb03SLiam R. Howlett /* Use ULONG_MAX here to ensure all VMAs in the mm are unmapped */ 3148763ecb03SLiam R. Howlett unmap_vmas(&tlb, &mm->mm_mt, vma, 0, ULONG_MAX); 3149bf3980c8SSuren Baghdasaryan mmap_read_unlock(mm); 3150bf3980c8SSuren Baghdasaryan 3151bf3980c8SSuren Baghdasaryan /* 3152bf3980c8SSuren Baghdasaryan * Set MMF_OOM_SKIP to hide this task from the oom killer/reaper 3153b3541d91SSuren Baghdasaryan * because the memory has been already freed. 3154bf3980c8SSuren Baghdasaryan */ 3155bf3980c8SSuren Baghdasaryan set_bit(MMF_OOM_SKIP, &mm->flags); 3156bf3980c8SSuren Baghdasaryan mmap_write_lock(mm); 3157763ecb03SLiam R. Howlett free_pgtables(&tlb, &mm->mm_mt, vma, FIRST_USER_ADDRESS, 3158763ecb03SLiam R. Howlett USER_PGTABLES_CEILING); 3159ae8eba8bSWill Deacon tlb_finish_mmu(&tlb); 31601da177e4SLinus Torvalds 3161763ecb03SLiam R. Howlett /* 3162763ecb03SLiam R. Howlett * Walk the list again, actually closing and freeing it, with preemption 3163763ecb03SLiam R. Howlett * enabled, without holding any MM locks besides the unreachable 3164763ecb03SLiam R. Howlett * mmap_write_lock. 3165763ecb03SLiam R. Howlett */ 3166763ecb03SLiam R. Howlett do { 31674f74d2c8SLinus Torvalds if (vma->vm_flags & VM_ACCOUNT) 31684f74d2c8SLinus Torvalds nr_accounted += vma_pages(vma); 3169763ecb03SLiam R. Howlett remove_vma(vma); 3170763ecb03SLiam R. Howlett count++; 31710a3b3c25SPaul E. McKenney cond_resched(); 3172763ecb03SLiam R. Howlett } while ((vma = mas_find(&mas, ULONG_MAX)) != NULL); 3173763ecb03SLiam R. Howlett 3174763ecb03SLiam R. Howlett BUG_ON(count != mm->map_count); 3175d4af56c5SLiam R. Howlett 3176d4af56c5SLiam R. Howlett trace_exit_mmap(mm); 3177d4af56c5SLiam R. Howlett __mt_destroy(&mm->mm_mt); 317864591e86SSuren Baghdasaryan mmap_write_unlock(mm); 31794f74d2c8SLinus Torvalds vm_unacct_memory(nr_accounted); 31801da177e4SLinus Torvalds } 31811da177e4SLinus Torvalds 31821da177e4SLinus Torvalds /* Insert vm structure into process list sorted by address 31831da177e4SLinus Torvalds * and into the inode's i_mmap tree. If vm_file is non-NULL 3184c8c06efaSDavidlohr Bueso * then i_mmap_rwsem is taken here. 31851da177e4SLinus Torvalds */ 31861da177e4SLinus Torvalds int insert_vm_struct(struct mm_struct *mm, struct vm_area_struct *vma) 31871da177e4SLinus Torvalds { 3188d4af56c5SLiam R. Howlett unsigned long charged = vma_pages(vma); 31891da177e4SLinus Torvalds 3190d4af56c5SLiam R. Howlett 3191d0601a50SLiam R. Howlett if (find_vma_intersection(mm, vma->vm_start, vma->vm_end)) 3192c9d13f5fSChen Gang return -ENOMEM; 3193d4af56c5SLiam R. Howlett 3194c9d13f5fSChen Gang if ((vma->vm_flags & VM_ACCOUNT) && 3195d4af56c5SLiam R. Howlett security_vm_enough_memory_mm(mm, charged)) 3196c9d13f5fSChen Gang return -ENOMEM; 3197c9d13f5fSChen Gang 31981da177e4SLinus Torvalds /* 31991da177e4SLinus Torvalds * The vm_pgoff of a purely anonymous vma should be irrelevant 32001da177e4SLinus Torvalds * until its first write fault, when page's anon_vma and index 32011da177e4SLinus Torvalds * are set. But now set the vm_pgoff it will almost certainly 32021da177e4SLinus Torvalds * end up with (unless mremap moves it elsewhere before that 32031da177e4SLinus Torvalds * first wfault), so /proc/pid/maps tells a consistent story. 32041da177e4SLinus Torvalds * 32051da177e4SLinus Torvalds * By setting it to reflect the virtual start address of the 32061da177e4SLinus Torvalds * vma, merges and splits can happen in a seamless way, just 32071da177e4SLinus Torvalds * using the existing file pgoff checks and manipulations. 32088332326eSLiao Pingfang * Similarly in do_mmap and in do_brk_flags. 32091da177e4SLinus Torvalds */ 32108a9cc3b5SOleg Nesterov if (vma_is_anonymous(vma)) { 32111da177e4SLinus Torvalds BUG_ON(vma->anon_vma); 32121da177e4SLinus Torvalds vma->vm_pgoff = vma->vm_start >> PAGE_SHIFT; 32131da177e4SLinus Torvalds } 32142b144498SSrikar Dronamraju 3215763ecb03SLiam R. Howlett if (vma_link(mm, vma)) { 3216d4af56c5SLiam R. Howlett vm_unacct_memory(charged); 3217d4af56c5SLiam R. Howlett return -ENOMEM; 3218d4af56c5SLiam R. Howlett } 3219d4af56c5SLiam R. Howlett 32201da177e4SLinus Torvalds return 0; 32211da177e4SLinus Torvalds } 32221da177e4SLinus Torvalds 32231da177e4SLinus Torvalds /* 32241da177e4SLinus Torvalds * Copy the vma structure to a new location in the same mm, 32251da177e4SLinus Torvalds * prior to moving page table entries, to effect an mremap move. 32261da177e4SLinus Torvalds */ 32271da177e4SLinus Torvalds struct vm_area_struct *copy_vma(struct vm_area_struct **vmap, 322838a76013SMichel Lespinasse unsigned long addr, unsigned long len, pgoff_t pgoff, 322938a76013SMichel Lespinasse bool *need_rmap_locks) 32301da177e4SLinus Torvalds { 32311da177e4SLinus Torvalds struct vm_area_struct *vma = *vmap; 32321da177e4SLinus Torvalds unsigned long vma_start = vma->vm_start; 32331da177e4SLinus Torvalds struct mm_struct *mm = vma->vm_mm; 32341da177e4SLinus Torvalds struct vm_area_struct *new_vma, *prev; 3235948f017bSAndrea Arcangeli bool faulted_in_anon_vma = true; 3236*076f16bfSLiam R. Howlett VMA_ITERATOR(vmi, mm, addr); 32371da177e4SLinus Torvalds 3238d4af56c5SLiam R. Howlett validate_mm_mt(mm); 32391da177e4SLinus Torvalds /* 32401da177e4SLinus Torvalds * If anonymous vma has not yet been faulted, update new pgoff 32411da177e4SLinus Torvalds * to match new location, to increase its chance of merging. 32421da177e4SLinus Torvalds */ 3243ce75799bSOleg Nesterov if (unlikely(vma_is_anonymous(vma) && !vma->anon_vma)) { 32441da177e4SLinus Torvalds pgoff = addr >> PAGE_SHIFT; 3245948f017bSAndrea Arcangeli faulted_in_anon_vma = false; 3246948f017bSAndrea Arcangeli } 32471da177e4SLinus Torvalds 3248763ecb03SLiam R. Howlett new_vma = find_vma_prev(mm, addr, &prev); 3249763ecb03SLiam R. Howlett if (new_vma && new_vma->vm_start < addr + len) 32506597d783SHugh Dickins return NULL; /* should never get here */ 3251524e00b3SLiam R. Howlett 3252*076f16bfSLiam R. Howlett new_vma = vmi_vma_merge(&vmi, mm, prev, addr, addr + len, vma->vm_flags, 325319a809afSAndrea Arcangeli vma->anon_vma, vma->vm_file, pgoff, vma_policy(vma), 32545c26f6acSSuren Baghdasaryan vma->vm_userfaultfd_ctx, anon_vma_name(vma)); 32551da177e4SLinus Torvalds if (new_vma) { 32561da177e4SLinus Torvalds /* 32571da177e4SLinus Torvalds * Source vma may have been merged into new_vma 32581da177e4SLinus Torvalds */ 3259948f017bSAndrea Arcangeli if (unlikely(vma_start >= new_vma->vm_start && 3260948f017bSAndrea Arcangeli vma_start < new_vma->vm_end)) { 3261948f017bSAndrea Arcangeli /* 3262948f017bSAndrea Arcangeli * The only way we can get a vma_merge with 3263948f017bSAndrea Arcangeli * self during an mremap is if the vma hasn't 3264948f017bSAndrea Arcangeli * been faulted in yet and we were allowed to 3265948f017bSAndrea Arcangeli * reset the dst vma->vm_pgoff to the 3266948f017bSAndrea Arcangeli * destination address of the mremap to allow 3267948f017bSAndrea Arcangeli * the merge to happen. mremap must change the 3268948f017bSAndrea Arcangeli * vm_pgoff linearity between src and dst vmas 3269948f017bSAndrea Arcangeli * (in turn preventing a vma_merge) to be 3270948f017bSAndrea Arcangeli * safe. It is only safe to keep the vm_pgoff 3271948f017bSAndrea Arcangeli * linear if there are no pages mapped yet. 3272948f017bSAndrea Arcangeli */ 327381d1b09cSSasha Levin VM_BUG_ON_VMA(faulted_in_anon_vma, new_vma); 327438a76013SMichel Lespinasse *vmap = vma = new_vma; 3275108d6642SMichel Lespinasse } 327638a76013SMichel Lespinasse *need_rmap_locks = (new_vma->vm_pgoff <= vma->vm_pgoff); 32771da177e4SLinus Torvalds } else { 32783928d4f5SLinus Torvalds new_vma = vm_area_dup(vma); 3279e3975891SChen Gang if (!new_vma) 3280e3975891SChen Gang goto out; 32811da177e4SLinus Torvalds new_vma->vm_start = addr; 32821da177e4SLinus Torvalds new_vma->vm_end = addr + len; 32831da177e4SLinus Torvalds new_vma->vm_pgoff = pgoff; 3284ef0855d3SOleg Nesterov if (vma_dup_policy(vma, new_vma)) 3285523d4e20SMichel Lespinasse goto out_free_vma; 3286523d4e20SMichel Lespinasse if (anon_vma_clone(new_vma, vma)) 3287523d4e20SMichel Lespinasse goto out_free_mempol; 3288e9714acfSKonstantin Khlebnikov if (new_vma->vm_file) 32891da177e4SLinus Torvalds get_file(new_vma->vm_file); 32901da177e4SLinus Torvalds if (new_vma->vm_ops && new_vma->vm_ops->open) 32911da177e4SLinus Torvalds new_vma->vm_ops->open(new_vma); 3292763ecb03SLiam R. Howlett if (vma_link(mm, new_vma)) 3293524e00b3SLiam R. Howlett goto out_vma_link; 329438a76013SMichel Lespinasse *need_rmap_locks = false; 32951da177e4SLinus Torvalds } 3296d4af56c5SLiam R. Howlett validate_mm_mt(mm); 32971da177e4SLinus Torvalds return new_vma; 32985beb4930SRik van Riel 3299524e00b3SLiam R. Howlett out_vma_link: 3300524e00b3SLiam R. Howlett if (new_vma->vm_ops && new_vma->vm_ops->close) 3301524e00b3SLiam R. Howlett new_vma->vm_ops->close(new_vma); 330292b73996SLiam Howlett 330392b73996SLiam Howlett if (new_vma->vm_file) 330492b73996SLiam Howlett fput(new_vma->vm_file); 330592b73996SLiam Howlett 330692b73996SLiam Howlett unlink_anon_vmas(new_vma); 33075beb4930SRik van Riel out_free_mempol: 3308ef0855d3SOleg Nesterov mpol_put(vma_policy(new_vma)); 33095beb4930SRik van Riel out_free_vma: 33103928d4f5SLinus Torvalds vm_area_free(new_vma); 3311e3975891SChen Gang out: 3312d4af56c5SLiam R. Howlett validate_mm_mt(mm); 33135beb4930SRik van Riel return NULL; 33141da177e4SLinus Torvalds } 3315119f657cSakpm@osdl.org 3316119f657cSakpm@osdl.org /* 3317119f657cSakpm@osdl.org * Return true if the calling process may expand its vm space by the passed 3318119f657cSakpm@osdl.org * number of pages 3319119f657cSakpm@osdl.org */ 332084638335SKonstantin Khlebnikov bool may_expand_vm(struct mm_struct *mm, vm_flags_t flags, unsigned long npages) 3321119f657cSakpm@osdl.org { 332284638335SKonstantin Khlebnikov if (mm->total_vm + npages > rlimit(RLIMIT_AS) >> PAGE_SHIFT) 332384638335SKonstantin Khlebnikov return false; 3324119f657cSakpm@osdl.org 3325d977d56cSKonstantin Khlebnikov if (is_data_mapping(flags) && 3326d977d56cSKonstantin Khlebnikov mm->data_vm + npages > rlimit(RLIMIT_DATA) >> PAGE_SHIFT) { 3327f4fcd558SKonstantin Khlebnikov /* Workaround for Valgrind */ 3328f4fcd558SKonstantin Khlebnikov if (rlimit(RLIMIT_DATA) == 0 && 3329f4fcd558SKonstantin Khlebnikov mm->data_vm + npages <= rlimit_max(RLIMIT_DATA) >> PAGE_SHIFT) 3330f4fcd558SKonstantin Khlebnikov return true; 333157a7702bSDavid Woodhouse 333257a7702bSDavid Woodhouse pr_warn_once("%s (%d): VmData %lu exceed data ulimit %lu. Update limits%s.\n", 3333d977d56cSKonstantin Khlebnikov current->comm, current->pid, 3334d977d56cSKonstantin Khlebnikov (mm->data_vm + npages) << PAGE_SHIFT, 333557a7702bSDavid Woodhouse rlimit(RLIMIT_DATA), 333657a7702bSDavid Woodhouse ignore_rlimit_data ? "" : " or use boot option ignore_rlimit_data"); 333757a7702bSDavid Woodhouse 333857a7702bSDavid Woodhouse if (!ignore_rlimit_data) 3339d977d56cSKonstantin Khlebnikov return false; 3340d977d56cSKonstantin Khlebnikov } 3341119f657cSakpm@osdl.org 334284638335SKonstantin Khlebnikov return true; 334384638335SKonstantin Khlebnikov } 334484638335SKonstantin Khlebnikov 334584638335SKonstantin Khlebnikov void vm_stat_account(struct mm_struct *mm, vm_flags_t flags, long npages) 334684638335SKonstantin Khlebnikov { 33477866076bSPeng Liu WRITE_ONCE(mm->total_vm, READ_ONCE(mm->total_vm)+npages); 334884638335SKonstantin Khlebnikov 3349d977d56cSKonstantin Khlebnikov if (is_exec_mapping(flags)) 335084638335SKonstantin Khlebnikov mm->exec_vm += npages; 3351d977d56cSKonstantin Khlebnikov else if (is_stack_mapping(flags)) 335284638335SKonstantin Khlebnikov mm->stack_vm += npages; 3353d977d56cSKonstantin Khlebnikov else if (is_data_mapping(flags)) 335484638335SKonstantin Khlebnikov mm->data_vm += npages; 3355119f657cSakpm@osdl.org } 3356fa5dc22fSRoland McGrath 3357b3ec9f33SSouptick Joarder static vm_fault_t special_mapping_fault(struct vm_fault *vmf); 3358a62c34bdSAndy Lutomirski 3359a62c34bdSAndy Lutomirski /* 3360a62c34bdSAndy Lutomirski * Having a close hook prevents vma merging regardless of flags. 3361a62c34bdSAndy Lutomirski */ 3362a62c34bdSAndy Lutomirski static void special_mapping_close(struct vm_area_struct *vma) 3363a62c34bdSAndy Lutomirski { 3364a62c34bdSAndy Lutomirski } 3365a62c34bdSAndy Lutomirski 3366a62c34bdSAndy Lutomirski static const char *special_mapping_name(struct vm_area_struct *vma) 3367a62c34bdSAndy Lutomirski { 3368a62c34bdSAndy Lutomirski return ((struct vm_special_mapping *)vma->vm_private_data)->name; 3369a62c34bdSAndy Lutomirski } 3370a62c34bdSAndy Lutomirski 337114d07113SBrian Geffon static int special_mapping_mremap(struct vm_area_struct *new_vma) 3372b059a453SDmitry Safonov { 3373b059a453SDmitry Safonov struct vm_special_mapping *sm = new_vma->vm_private_data; 3374b059a453SDmitry Safonov 3375280e87e9SDmitry Safonov if (WARN_ON_ONCE(current->mm != new_vma->vm_mm)) 3376280e87e9SDmitry Safonov return -EFAULT; 3377280e87e9SDmitry Safonov 3378b059a453SDmitry Safonov if (sm->mremap) 3379b059a453SDmitry Safonov return sm->mremap(sm, new_vma); 3380280e87e9SDmitry Safonov 3381b059a453SDmitry Safonov return 0; 3382b059a453SDmitry Safonov } 3383b059a453SDmitry Safonov 3384871402e0SDmitry Safonov static int special_mapping_split(struct vm_area_struct *vma, unsigned long addr) 3385871402e0SDmitry Safonov { 3386871402e0SDmitry Safonov /* 3387871402e0SDmitry Safonov * Forbid splitting special mappings - kernel has expectations over 3388871402e0SDmitry Safonov * the number of pages in mapping. Together with VM_DONTEXPAND 3389871402e0SDmitry Safonov * the size of vma should stay the same over the special mapping's 3390871402e0SDmitry Safonov * lifetime. 3391871402e0SDmitry Safonov */ 3392871402e0SDmitry Safonov return -EINVAL; 3393871402e0SDmitry Safonov } 3394871402e0SDmitry Safonov 3395a62c34bdSAndy Lutomirski static const struct vm_operations_struct special_mapping_vmops = { 3396a62c34bdSAndy Lutomirski .close = special_mapping_close, 3397a62c34bdSAndy Lutomirski .fault = special_mapping_fault, 3398b059a453SDmitry Safonov .mremap = special_mapping_mremap, 3399a62c34bdSAndy Lutomirski .name = special_mapping_name, 3400af34ebebSDmitry Safonov /* vDSO code relies that VVAR can't be accessed remotely */ 3401af34ebebSDmitry Safonov .access = NULL, 3402871402e0SDmitry Safonov .may_split = special_mapping_split, 3403a62c34bdSAndy Lutomirski }; 3404a62c34bdSAndy Lutomirski 3405a62c34bdSAndy Lutomirski static const struct vm_operations_struct legacy_special_mapping_vmops = { 3406a62c34bdSAndy Lutomirski .close = special_mapping_close, 3407a62c34bdSAndy Lutomirski .fault = special_mapping_fault, 3408a62c34bdSAndy Lutomirski }; 3409fa5dc22fSRoland McGrath 3410b3ec9f33SSouptick Joarder static vm_fault_t special_mapping_fault(struct vm_fault *vmf) 3411fa5dc22fSRoland McGrath { 341211bac800SDave Jiang struct vm_area_struct *vma = vmf->vma; 3413b1d0e4f5SNick Piggin pgoff_t pgoff; 3414fa5dc22fSRoland McGrath struct page **pages; 3415fa5dc22fSRoland McGrath 3416f872f540SAndy Lutomirski if (vma->vm_ops == &legacy_special_mapping_vmops) { 3417a62c34bdSAndy Lutomirski pages = vma->vm_private_data; 3418f872f540SAndy Lutomirski } else { 3419f872f540SAndy Lutomirski struct vm_special_mapping *sm = vma->vm_private_data; 3420f872f540SAndy Lutomirski 3421f872f540SAndy Lutomirski if (sm->fault) 342211bac800SDave Jiang return sm->fault(sm, vmf->vma, vmf); 3423f872f540SAndy Lutomirski 3424f872f540SAndy Lutomirski pages = sm->pages; 3425f872f540SAndy Lutomirski } 3426a62c34bdSAndy Lutomirski 34278a9cc3b5SOleg Nesterov for (pgoff = vmf->pgoff; pgoff && *pages; ++pages) 3428b1d0e4f5SNick Piggin pgoff--; 3429fa5dc22fSRoland McGrath 3430fa5dc22fSRoland McGrath if (*pages) { 3431fa5dc22fSRoland McGrath struct page *page = *pages; 3432fa5dc22fSRoland McGrath get_page(page); 3433b1d0e4f5SNick Piggin vmf->page = page; 3434b1d0e4f5SNick Piggin return 0; 3435fa5dc22fSRoland McGrath } 3436fa5dc22fSRoland McGrath 3437b1d0e4f5SNick Piggin return VM_FAULT_SIGBUS; 3438fa5dc22fSRoland McGrath } 3439fa5dc22fSRoland McGrath 3440a62c34bdSAndy Lutomirski static struct vm_area_struct *__install_special_mapping( 3441a62c34bdSAndy Lutomirski struct mm_struct *mm, 3442fa5dc22fSRoland McGrath unsigned long addr, unsigned long len, 344327f28b97SChen Gang unsigned long vm_flags, void *priv, 344427f28b97SChen Gang const struct vm_operations_struct *ops) 3445fa5dc22fSRoland McGrath { 3446462e635eSTavis Ormandy int ret; 3447fa5dc22fSRoland McGrath struct vm_area_struct *vma; 3448fa5dc22fSRoland McGrath 3449d4af56c5SLiam R. Howlett validate_mm_mt(mm); 3450490fc053SLinus Torvalds vma = vm_area_alloc(mm); 3451fa5dc22fSRoland McGrath if (unlikely(vma == NULL)) 34523935ed6aSStefani Seibold return ERR_PTR(-ENOMEM); 3453fa5dc22fSRoland McGrath 3454fa5dc22fSRoland McGrath vma->vm_start = addr; 3455fa5dc22fSRoland McGrath vma->vm_end = addr + len; 3456fa5dc22fSRoland McGrath 3457d9104d1cSCyrill Gorcunov vma->vm_flags = vm_flags | mm->def_flags | VM_DONTEXPAND | VM_SOFTDIRTY; 34581fc09228SHugh Dickins vma->vm_flags &= VM_LOCKED_CLEAR_MASK; 34593ed75eb8SColy Li vma->vm_page_prot = vm_get_page_prot(vma->vm_flags); 3460fa5dc22fSRoland McGrath 3461a62c34bdSAndy Lutomirski vma->vm_ops = ops; 3462a62c34bdSAndy Lutomirski vma->vm_private_data = priv; 3463fa5dc22fSRoland McGrath 3464462e635eSTavis Ormandy ret = insert_vm_struct(mm, vma); 3465462e635eSTavis Ormandy if (ret) 3466462e635eSTavis Ormandy goto out; 3467fa5dc22fSRoland McGrath 346884638335SKonstantin Khlebnikov vm_stat_account(mm, vma->vm_flags, len >> PAGE_SHIFT); 3469fa5dc22fSRoland McGrath 3470cdd6c482SIngo Molnar perf_event_mmap(vma); 3471089dd79dSPeter Zijlstra 3472d4af56c5SLiam R. Howlett validate_mm_mt(mm); 34733935ed6aSStefani Seibold return vma; 3474462e635eSTavis Ormandy 3475462e635eSTavis Ormandy out: 34763928d4f5SLinus Torvalds vm_area_free(vma); 3477d4af56c5SLiam R. Howlett validate_mm_mt(mm); 34783935ed6aSStefani Seibold return ERR_PTR(ret); 34793935ed6aSStefani Seibold } 34803935ed6aSStefani Seibold 34812eefd878SDmitry Safonov bool vma_is_special_mapping(const struct vm_area_struct *vma, 34822eefd878SDmitry Safonov const struct vm_special_mapping *sm) 34832eefd878SDmitry Safonov { 34842eefd878SDmitry Safonov return vma->vm_private_data == sm && 34852eefd878SDmitry Safonov (vma->vm_ops == &special_mapping_vmops || 34862eefd878SDmitry Safonov vma->vm_ops == &legacy_special_mapping_vmops); 34872eefd878SDmitry Safonov } 34882eefd878SDmitry Safonov 3489a62c34bdSAndy Lutomirski /* 3490c1e8d7c6SMichel Lespinasse * Called with mm->mmap_lock held for writing. 3491a62c34bdSAndy Lutomirski * Insert a new vma covering the given region, with the given flags. 3492a62c34bdSAndy Lutomirski * Its pages are supplied by the given array of struct page *. 3493a62c34bdSAndy Lutomirski * The array can be shorter than len >> PAGE_SHIFT if it's null-terminated. 3494a62c34bdSAndy Lutomirski * The region past the last page supplied will always produce SIGBUS. 3495a62c34bdSAndy Lutomirski * The array pointer and the pages it points to are assumed to stay alive 3496a62c34bdSAndy Lutomirski * for as long as this mapping might exist. 3497a62c34bdSAndy Lutomirski */ 3498a62c34bdSAndy Lutomirski struct vm_area_struct *_install_special_mapping( 3499a62c34bdSAndy Lutomirski struct mm_struct *mm, 3500a62c34bdSAndy Lutomirski unsigned long addr, unsigned long len, 3501a62c34bdSAndy Lutomirski unsigned long vm_flags, const struct vm_special_mapping *spec) 3502a62c34bdSAndy Lutomirski { 350327f28b97SChen Gang return __install_special_mapping(mm, addr, len, vm_flags, (void *)spec, 350427f28b97SChen Gang &special_mapping_vmops); 3505a62c34bdSAndy Lutomirski } 3506a62c34bdSAndy Lutomirski 35073935ed6aSStefani Seibold int install_special_mapping(struct mm_struct *mm, 35083935ed6aSStefani Seibold unsigned long addr, unsigned long len, 35093935ed6aSStefani Seibold unsigned long vm_flags, struct page **pages) 35103935ed6aSStefani Seibold { 3511a62c34bdSAndy Lutomirski struct vm_area_struct *vma = __install_special_mapping( 351227f28b97SChen Gang mm, addr, len, vm_flags, (void *)pages, 351327f28b97SChen Gang &legacy_special_mapping_vmops); 35143935ed6aSStefani Seibold 351514bd5b45SDuan Jiong return PTR_ERR_OR_ZERO(vma); 3516fa5dc22fSRoland McGrath } 35177906d00cSAndrea Arcangeli 35187906d00cSAndrea Arcangeli static DEFINE_MUTEX(mm_all_locks_mutex); 35197906d00cSAndrea Arcangeli 3520454ed842SPeter Zijlstra static void vm_lock_anon_vma(struct mm_struct *mm, struct anon_vma *anon_vma) 35217906d00cSAndrea Arcangeli { 3522f808c13fSDavidlohr Bueso if (!test_bit(0, (unsigned long *) &anon_vma->root->rb_root.rb_root.rb_node)) { 35237906d00cSAndrea Arcangeli /* 35247906d00cSAndrea Arcangeli * The LSB of head.next can't change from under us 35257906d00cSAndrea Arcangeli * because we hold the mm_all_locks_mutex. 35267906d00cSAndrea Arcangeli */ 3527da1c55f1SMichel Lespinasse down_write_nest_lock(&anon_vma->root->rwsem, &mm->mmap_lock); 35287906d00cSAndrea Arcangeli /* 35297906d00cSAndrea Arcangeli * We can safely modify head.next after taking the 35305a505085SIngo Molnar * anon_vma->root->rwsem. If some other vma in this mm shares 35317906d00cSAndrea Arcangeli * the same anon_vma we won't take it again. 35327906d00cSAndrea Arcangeli * 35337906d00cSAndrea Arcangeli * No need of atomic instructions here, head.next 35347906d00cSAndrea Arcangeli * can't change from under us thanks to the 35355a505085SIngo Molnar * anon_vma->root->rwsem. 35367906d00cSAndrea Arcangeli */ 35377906d00cSAndrea Arcangeli if (__test_and_set_bit(0, (unsigned long *) 3538f808c13fSDavidlohr Bueso &anon_vma->root->rb_root.rb_root.rb_node)) 35397906d00cSAndrea Arcangeli BUG(); 35407906d00cSAndrea Arcangeli } 35417906d00cSAndrea Arcangeli } 35427906d00cSAndrea Arcangeli 3543454ed842SPeter Zijlstra static void vm_lock_mapping(struct mm_struct *mm, struct address_space *mapping) 35447906d00cSAndrea Arcangeli { 35457906d00cSAndrea Arcangeli if (!test_bit(AS_MM_ALL_LOCKS, &mapping->flags)) { 35467906d00cSAndrea Arcangeli /* 35477906d00cSAndrea Arcangeli * AS_MM_ALL_LOCKS can't change from under us because 35487906d00cSAndrea Arcangeli * we hold the mm_all_locks_mutex. 35497906d00cSAndrea Arcangeli * 35507906d00cSAndrea Arcangeli * Operations on ->flags have to be atomic because 35517906d00cSAndrea Arcangeli * even if AS_MM_ALL_LOCKS is stable thanks to the 35527906d00cSAndrea Arcangeli * mm_all_locks_mutex, there may be other cpus 35537906d00cSAndrea Arcangeli * changing other bitflags in parallel to us. 35547906d00cSAndrea Arcangeli */ 35557906d00cSAndrea Arcangeli if (test_and_set_bit(AS_MM_ALL_LOCKS, &mapping->flags)) 35567906d00cSAndrea Arcangeli BUG(); 3557da1c55f1SMichel Lespinasse down_write_nest_lock(&mapping->i_mmap_rwsem, &mm->mmap_lock); 35587906d00cSAndrea Arcangeli } 35597906d00cSAndrea Arcangeli } 35607906d00cSAndrea Arcangeli 35617906d00cSAndrea Arcangeli /* 35627906d00cSAndrea Arcangeli * This operation locks against the VM for all pte/vma/mm related 35637906d00cSAndrea Arcangeli * operations that could ever happen on a certain mm. This includes 35647906d00cSAndrea Arcangeli * vmtruncate, try_to_unmap, and all page faults. 35657906d00cSAndrea Arcangeli * 3566c1e8d7c6SMichel Lespinasse * The caller must take the mmap_lock in write mode before calling 35677906d00cSAndrea Arcangeli * mm_take_all_locks(). The caller isn't allowed to release the 3568c1e8d7c6SMichel Lespinasse * mmap_lock until mm_drop_all_locks() returns. 35697906d00cSAndrea Arcangeli * 3570c1e8d7c6SMichel Lespinasse * mmap_lock in write mode is required in order to block all operations 35717906d00cSAndrea Arcangeli * that could modify pagetables and free pages without need of 357227ba0644SKirill A. Shutemov * altering the vma layout. It's also needed in write mode to avoid new 35737906d00cSAndrea Arcangeli * anon_vmas to be associated with existing vmas. 35747906d00cSAndrea Arcangeli * 35757906d00cSAndrea Arcangeli * A single task can't take more than one mm_take_all_locks() in a row 35767906d00cSAndrea Arcangeli * or it would deadlock. 35777906d00cSAndrea Arcangeli * 3578bf181b9fSMichel Lespinasse * The LSB in anon_vma->rb_root.rb_node and the AS_MM_ALL_LOCKS bitflag in 35797906d00cSAndrea Arcangeli * mapping->flags avoid to take the same lock twice, if more than one 35807906d00cSAndrea Arcangeli * vma in this mm is backed by the same anon_vma or address_space. 35817906d00cSAndrea Arcangeli * 358288f306b6SKirill A. Shutemov * We take locks in following order, accordingly to comment at beginning 358388f306b6SKirill A. Shutemov * of mm/rmap.c: 358488f306b6SKirill A. Shutemov * - all hugetlbfs_i_mmap_rwsem_key locks (aka mapping->i_mmap_rwsem for 358588f306b6SKirill A. Shutemov * hugetlb mapping); 358688f306b6SKirill A. Shutemov * - all i_mmap_rwsem locks; 358788f306b6SKirill A. Shutemov * - all anon_vma->rwseml 358888f306b6SKirill A. Shutemov * 358988f306b6SKirill A. Shutemov * We can take all locks within these types randomly because the VM code 359088f306b6SKirill A. Shutemov * doesn't nest them and we protected from parallel mm_take_all_locks() by 359188f306b6SKirill A. Shutemov * mm_all_locks_mutex. 35927906d00cSAndrea Arcangeli * 35937906d00cSAndrea Arcangeli * mm_take_all_locks() and mm_drop_all_locks are expensive operations 35947906d00cSAndrea Arcangeli * that may have to take thousand of locks. 35957906d00cSAndrea Arcangeli * 35967906d00cSAndrea Arcangeli * mm_take_all_locks() can fail if it's interrupted by signals. 35977906d00cSAndrea Arcangeli */ 35987906d00cSAndrea Arcangeli int mm_take_all_locks(struct mm_struct *mm) 35997906d00cSAndrea Arcangeli { 36007906d00cSAndrea Arcangeli struct vm_area_struct *vma; 36015beb4930SRik van Riel struct anon_vma_chain *avc; 3602763ecb03SLiam R. Howlett MA_STATE(mas, &mm->mm_mt, 0, 0); 36037906d00cSAndrea Arcangeli 3604325bca1fSRolf Eike Beer mmap_assert_write_locked(mm); 36057906d00cSAndrea Arcangeli 36067906d00cSAndrea Arcangeli mutex_lock(&mm_all_locks_mutex); 36077906d00cSAndrea Arcangeli 3608763ecb03SLiam R. Howlett mas_for_each(&mas, vma, ULONG_MAX) { 36097906d00cSAndrea Arcangeli if (signal_pending(current)) 36107906d00cSAndrea Arcangeli goto out_unlock; 361188f306b6SKirill A. Shutemov if (vma->vm_file && vma->vm_file->f_mapping && 361288f306b6SKirill A. Shutemov is_vm_hugetlb_page(vma)) 361388f306b6SKirill A. Shutemov vm_lock_mapping(mm, vma->vm_file->f_mapping); 361488f306b6SKirill A. Shutemov } 361588f306b6SKirill A. Shutemov 3616763ecb03SLiam R. Howlett mas_set(&mas, 0); 3617763ecb03SLiam R. Howlett mas_for_each(&mas, vma, ULONG_MAX) { 361888f306b6SKirill A. Shutemov if (signal_pending(current)) 361988f306b6SKirill A. Shutemov goto out_unlock; 362088f306b6SKirill A. Shutemov if (vma->vm_file && vma->vm_file->f_mapping && 362188f306b6SKirill A. Shutemov !is_vm_hugetlb_page(vma)) 3622454ed842SPeter Zijlstra vm_lock_mapping(mm, vma->vm_file->f_mapping); 36237906d00cSAndrea Arcangeli } 36247cd5a02fSPeter Zijlstra 3625763ecb03SLiam R. Howlett mas_set(&mas, 0); 3626763ecb03SLiam R. Howlett mas_for_each(&mas, vma, ULONG_MAX) { 36277cd5a02fSPeter Zijlstra if (signal_pending(current)) 36287cd5a02fSPeter Zijlstra goto out_unlock; 36297cd5a02fSPeter Zijlstra if (vma->anon_vma) 36305beb4930SRik van Riel list_for_each_entry(avc, &vma->anon_vma_chain, same_vma) 36315beb4930SRik van Riel vm_lock_anon_vma(mm, avc->anon_vma); 36327cd5a02fSPeter Zijlstra } 36337cd5a02fSPeter Zijlstra 3634584cff54SKautuk Consul return 0; 36357906d00cSAndrea Arcangeli 36367906d00cSAndrea Arcangeli out_unlock: 36377906d00cSAndrea Arcangeli mm_drop_all_locks(mm); 3638584cff54SKautuk Consul return -EINTR; 36397906d00cSAndrea Arcangeli } 36407906d00cSAndrea Arcangeli 36417906d00cSAndrea Arcangeli static void vm_unlock_anon_vma(struct anon_vma *anon_vma) 36427906d00cSAndrea Arcangeli { 3643f808c13fSDavidlohr Bueso if (test_bit(0, (unsigned long *) &anon_vma->root->rb_root.rb_root.rb_node)) { 36447906d00cSAndrea Arcangeli /* 36457906d00cSAndrea Arcangeli * The LSB of head.next can't change to 0 from under 36467906d00cSAndrea Arcangeli * us because we hold the mm_all_locks_mutex. 36477906d00cSAndrea Arcangeli * 36487906d00cSAndrea Arcangeli * We must however clear the bitflag before unlocking 3649bf181b9fSMichel Lespinasse * the vma so the users using the anon_vma->rb_root will 36507906d00cSAndrea Arcangeli * never see our bitflag. 36517906d00cSAndrea Arcangeli * 36527906d00cSAndrea Arcangeli * No need of atomic instructions here, head.next 36537906d00cSAndrea Arcangeli * can't change from under us until we release the 36545a505085SIngo Molnar * anon_vma->root->rwsem. 36557906d00cSAndrea Arcangeli */ 36567906d00cSAndrea Arcangeli if (!__test_and_clear_bit(0, (unsigned long *) 3657f808c13fSDavidlohr Bueso &anon_vma->root->rb_root.rb_root.rb_node)) 36587906d00cSAndrea Arcangeli BUG(); 365908b52706SKonstantin Khlebnikov anon_vma_unlock_write(anon_vma); 36607906d00cSAndrea Arcangeli } 36617906d00cSAndrea Arcangeli } 36627906d00cSAndrea Arcangeli 36637906d00cSAndrea Arcangeli static void vm_unlock_mapping(struct address_space *mapping) 36647906d00cSAndrea Arcangeli { 36657906d00cSAndrea Arcangeli if (test_bit(AS_MM_ALL_LOCKS, &mapping->flags)) { 36667906d00cSAndrea Arcangeli /* 36677906d00cSAndrea Arcangeli * AS_MM_ALL_LOCKS can't change to 0 from under us 36687906d00cSAndrea Arcangeli * because we hold the mm_all_locks_mutex. 36697906d00cSAndrea Arcangeli */ 367083cde9e8SDavidlohr Bueso i_mmap_unlock_write(mapping); 36717906d00cSAndrea Arcangeli if (!test_and_clear_bit(AS_MM_ALL_LOCKS, 36727906d00cSAndrea Arcangeli &mapping->flags)) 36737906d00cSAndrea Arcangeli BUG(); 36747906d00cSAndrea Arcangeli } 36757906d00cSAndrea Arcangeli } 36767906d00cSAndrea Arcangeli 36777906d00cSAndrea Arcangeli /* 3678c1e8d7c6SMichel Lespinasse * The mmap_lock cannot be released by the caller until 36797906d00cSAndrea Arcangeli * mm_drop_all_locks() returns. 36807906d00cSAndrea Arcangeli */ 36817906d00cSAndrea Arcangeli void mm_drop_all_locks(struct mm_struct *mm) 36827906d00cSAndrea Arcangeli { 36837906d00cSAndrea Arcangeli struct vm_area_struct *vma; 36845beb4930SRik van Riel struct anon_vma_chain *avc; 3685763ecb03SLiam R. Howlett MA_STATE(mas, &mm->mm_mt, 0, 0); 36867906d00cSAndrea Arcangeli 3687325bca1fSRolf Eike Beer mmap_assert_write_locked(mm); 36887906d00cSAndrea Arcangeli BUG_ON(!mutex_is_locked(&mm_all_locks_mutex)); 36897906d00cSAndrea Arcangeli 3690763ecb03SLiam R. Howlett mas_for_each(&mas, vma, ULONG_MAX) { 36917906d00cSAndrea Arcangeli if (vma->anon_vma) 36925beb4930SRik van Riel list_for_each_entry(avc, &vma->anon_vma_chain, same_vma) 36935beb4930SRik van Riel vm_unlock_anon_vma(avc->anon_vma); 36947906d00cSAndrea Arcangeli if (vma->vm_file && vma->vm_file->f_mapping) 36957906d00cSAndrea Arcangeli vm_unlock_mapping(vma->vm_file->f_mapping); 36967906d00cSAndrea Arcangeli } 36977906d00cSAndrea Arcangeli 36987906d00cSAndrea Arcangeli mutex_unlock(&mm_all_locks_mutex); 36997906d00cSAndrea Arcangeli } 37008feae131SDavid Howells 37018feae131SDavid Howells /* 37023edf41d8Sseokhoon.yoon * initialise the percpu counter for VM 37038feae131SDavid Howells */ 37048feae131SDavid Howells void __init mmap_init(void) 37058feae131SDavid Howells { 370600a62ce9SKOSAKI Motohiro int ret; 370700a62ce9SKOSAKI Motohiro 3708908c7f19STejun Heo ret = percpu_counter_init(&vm_committed_as, 0, GFP_KERNEL); 370900a62ce9SKOSAKI Motohiro VM_BUG_ON(ret); 37108feae131SDavid Howells } 3711c9b1d098SAndrew Shewmaker 3712c9b1d098SAndrew Shewmaker /* 3713c9b1d098SAndrew Shewmaker * Initialise sysctl_user_reserve_kbytes. 3714c9b1d098SAndrew Shewmaker * 3715c9b1d098SAndrew Shewmaker * This is intended to prevent a user from starting a single memory hogging 3716c9b1d098SAndrew Shewmaker * process, such that they cannot recover (kill the hog) in OVERCOMMIT_NEVER 3717c9b1d098SAndrew Shewmaker * mode. 3718c9b1d098SAndrew Shewmaker * 3719c9b1d098SAndrew Shewmaker * The default value is min(3% of free memory, 128MB) 3720c9b1d098SAndrew Shewmaker * 128MB is enough to recover with sshd/login, bash, and top/kill. 3721c9b1d098SAndrew Shewmaker */ 37221640879aSAndrew Shewmaker static int init_user_reserve(void) 3723c9b1d098SAndrew Shewmaker { 3724c9b1d098SAndrew Shewmaker unsigned long free_kbytes; 3725c9b1d098SAndrew Shewmaker 3726c41f012aSMichal Hocko free_kbytes = global_zone_page_state(NR_FREE_PAGES) << (PAGE_SHIFT - 10); 3727c9b1d098SAndrew Shewmaker 3728c9b1d098SAndrew Shewmaker sysctl_user_reserve_kbytes = min(free_kbytes / 32, 1UL << 17); 3729c9b1d098SAndrew Shewmaker return 0; 3730c9b1d098SAndrew Shewmaker } 3731a64fb3cdSPaul Gortmaker subsys_initcall(init_user_reserve); 37324eeab4f5SAndrew Shewmaker 37334eeab4f5SAndrew Shewmaker /* 37344eeab4f5SAndrew Shewmaker * Initialise sysctl_admin_reserve_kbytes. 37354eeab4f5SAndrew Shewmaker * 37364eeab4f5SAndrew Shewmaker * The purpose of sysctl_admin_reserve_kbytes is to allow the sys admin 37374eeab4f5SAndrew Shewmaker * to log in and kill a memory hogging process. 37384eeab4f5SAndrew Shewmaker * 37394eeab4f5SAndrew Shewmaker * Systems with more than 256MB will reserve 8MB, enough to recover 37404eeab4f5SAndrew Shewmaker * with sshd, bash, and top in OVERCOMMIT_GUESS. Smaller systems will 37414eeab4f5SAndrew Shewmaker * only reserve 3% of free pages by default. 37424eeab4f5SAndrew Shewmaker */ 37431640879aSAndrew Shewmaker static int init_admin_reserve(void) 37444eeab4f5SAndrew Shewmaker { 37454eeab4f5SAndrew Shewmaker unsigned long free_kbytes; 37464eeab4f5SAndrew Shewmaker 3747c41f012aSMichal Hocko free_kbytes = global_zone_page_state(NR_FREE_PAGES) << (PAGE_SHIFT - 10); 37484eeab4f5SAndrew Shewmaker 37494eeab4f5SAndrew Shewmaker sysctl_admin_reserve_kbytes = min(free_kbytes / 32, 1UL << 13); 37504eeab4f5SAndrew Shewmaker return 0; 37514eeab4f5SAndrew Shewmaker } 3752a64fb3cdSPaul Gortmaker subsys_initcall(init_admin_reserve); 37531640879aSAndrew Shewmaker 37541640879aSAndrew Shewmaker /* 37551640879aSAndrew Shewmaker * Reinititalise user and admin reserves if memory is added or removed. 37561640879aSAndrew Shewmaker * 37571640879aSAndrew Shewmaker * The default user reserve max is 128MB, and the default max for the 37581640879aSAndrew Shewmaker * admin reserve is 8MB. These are usually, but not always, enough to 37591640879aSAndrew Shewmaker * enable recovery from a memory hogging process using login/sshd, a shell, 37601640879aSAndrew Shewmaker * and tools like top. It may make sense to increase or even disable the 37611640879aSAndrew Shewmaker * reserve depending on the existence of swap or variations in the recovery 37621640879aSAndrew Shewmaker * tools. So, the admin may have changed them. 37631640879aSAndrew Shewmaker * 37641640879aSAndrew Shewmaker * If memory is added and the reserves have been eliminated or increased above 37651640879aSAndrew Shewmaker * the default max, then we'll trust the admin. 37661640879aSAndrew Shewmaker * 37671640879aSAndrew Shewmaker * If memory is removed and there isn't enough free memory, then we 37681640879aSAndrew Shewmaker * need to reset the reserves. 37691640879aSAndrew Shewmaker * 37701640879aSAndrew Shewmaker * Otherwise keep the reserve set by the admin. 37711640879aSAndrew Shewmaker */ 37721640879aSAndrew Shewmaker static int reserve_mem_notifier(struct notifier_block *nb, 37731640879aSAndrew Shewmaker unsigned long action, void *data) 37741640879aSAndrew Shewmaker { 37751640879aSAndrew Shewmaker unsigned long tmp, free_kbytes; 37761640879aSAndrew Shewmaker 37771640879aSAndrew Shewmaker switch (action) { 37781640879aSAndrew Shewmaker case MEM_ONLINE: 37791640879aSAndrew Shewmaker /* Default max is 128MB. Leave alone if modified by operator. */ 37801640879aSAndrew Shewmaker tmp = sysctl_user_reserve_kbytes; 37811640879aSAndrew Shewmaker if (0 < tmp && tmp < (1UL << 17)) 37821640879aSAndrew Shewmaker init_user_reserve(); 37831640879aSAndrew Shewmaker 37841640879aSAndrew Shewmaker /* Default max is 8MB. Leave alone if modified by operator. */ 37851640879aSAndrew Shewmaker tmp = sysctl_admin_reserve_kbytes; 37861640879aSAndrew Shewmaker if (0 < tmp && tmp < (1UL << 13)) 37871640879aSAndrew Shewmaker init_admin_reserve(); 37881640879aSAndrew Shewmaker 37891640879aSAndrew Shewmaker break; 37901640879aSAndrew Shewmaker case MEM_OFFLINE: 3791c41f012aSMichal Hocko free_kbytes = global_zone_page_state(NR_FREE_PAGES) << (PAGE_SHIFT - 10); 37921640879aSAndrew Shewmaker 37931640879aSAndrew Shewmaker if (sysctl_user_reserve_kbytes > free_kbytes) { 37941640879aSAndrew Shewmaker init_user_reserve(); 37951640879aSAndrew Shewmaker pr_info("vm.user_reserve_kbytes reset to %lu\n", 37961640879aSAndrew Shewmaker sysctl_user_reserve_kbytes); 37971640879aSAndrew Shewmaker } 37981640879aSAndrew Shewmaker 37991640879aSAndrew Shewmaker if (sysctl_admin_reserve_kbytes > free_kbytes) { 38001640879aSAndrew Shewmaker init_admin_reserve(); 38011640879aSAndrew Shewmaker pr_info("vm.admin_reserve_kbytes reset to %lu\n", 38021640879aSAndrew Shewmaker sysctl_admin_reserve_kbytes); 38031640879aSAndrew Shewmaker } 38041640879aSAndrew Shewmaker break; 38051640879aSAndrew Shewmaker default: 38061640879aSAndrew Shewmaker break; 38071640879aSAndrew Shewmaker } 38081640879aSAndrew Shewmaker return NOTIFY_OK; 38091640879aSAndrew Shewmaker } 38101640879aSAndrew Shewmaker 38111640879aSAndrew Shewmaker static int __meminit init_reserve_notifier(void) 38121640879aSAndrew Shewmaker { 38131eeaa4fdSLiu Shixin if (hotplug_memory_notifier(reserve_mem_notifier, DEFAULT_CALLBACK_PRI)) 3814b1de0d13SMitchel Humpherys pr_err("Failed registering memory add/remove notifier for admin reserve\n"); 38151640879aSAndrew Shewmaker 38161640879aSAndrew Shewmaker return 0; 38171640879aSAndrew Shewmaker } 3818a64fb3cdSPaul Gortmaker subsys_initcall(init_reserve_notifier); 3819