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 435763ecb03SLiam R. Howlett static int vma_link(struct mm_struct *mm, struct vm_area_struct *vma) 4361da177e4SLinus Torvalds { 43779e4f2caSLiam R. Howlett VMA_ITERATOR(vmi, mm, 0); 4381da177e4SLinus Torvalds struct address_space *mapping = NULL; 4391da177e4SLinus Torvalds 44079e4f2caSLiam R. Howlett if (vma_iter_prealloc(&vmi)) 441d4af56c5SLiam R. Howlett return -ENOMEM; 442d4af56c5SLiam R. Howlett 44364ac4940SHuang Shijie if (vma->vm_file) { 4441da177e4SLinus Torvalds mapping = vma->vm_file->f_mapping; 44583cde9e8SDavidlohr Bueso i_mmap_lock_write(mapping); 44664ac4940SHuang Shijie } 4471da177e4SLinus Torvalds 44879e4f2caSLiam R. Howlett vma_iter_store(&vmi, vma); 4491da177e4SLinus Torvalds 450c154124fSLiam R. Howlett if (mapping) { 451c154124fSLiam R. Howlett __vma_link_file(vma, mapping); 45283cde9e8SDavidlohr Bueso i_mmap_unlock_write(mapping); 453c154124fSLiam R. Howlett } 4541da177e4SLinus Torvalds 4551da177e4SLinus Torvalds mm->map_count++; 4561da177e4SLinus Torvalds validate_mm(mm); 457d4af56c5SLiam R. Howlett return 0; 4581da177e4SLinus Torvalds } 4591da177e4SLinus Torvalds 4601da177e4SLinus Torvalds /* 4614dd1b841SLiam R. Howlett * vma_expand - Expand an existing VMA 4624dd1b841SLiam R. Howlett * 4634dd1b841SLiam R. Howlett * @mas: The maple state 4644dd1b841SLiam R. Howlett * @vma: The vma to expand 4654dd1b841SLiam R. Howlett * @start: The start of the vma 4664dd1b841SLiam R. Howlett * @end: The exclusive end of the vma 4674dd1b841SLiam R. Howlett * @pgoff: The page offset of vma 4684dd1b841SLiam R. Howlett * @next: The current of next vma. 4694dd1b841SLiam R. Howlett * 4704dd1b841SLiam R. Howlett * Expand @vma to @start and @end. Can expand off the start and end. Will 4714dd1b841SLiam R. Howlett * expand over @next if it's different from @vma and @end == @next->vm_end. 4724dd1b841SLiam R. Howlett * Checking if the @vma can expand and merge with @next needs to be handled by 4734dd1b841SLiam R. Howlett * the caller. 4744dd1b841SLiam R. Howlett * 4754dd1b841SLiam R. Howlett * Returns: 0 on success 4764dd1b841SLiam R. Howlett */ 4773c441ab7SLiam R. Howlett inline int vma_expand(struct vma_iterator *vmi, struct vm_area_struct *vma, 4784dd1b841SLiam R. Howlett unsigned long start, unsigned long end, pgoff_t pgoff, 4794dd1b841SLiam R. Howlett struct vm_area_struct *next) 4804dd1b841SLiam R. Howlett { 4814dd1b841SLiam R. Howlett struct mm_struct *mm = vma->vm_mm; 4824dd1b841SLiam R. Howlett struct address_space *mapping = NULL; 4834dd1b841SLiam R. Howlett struct rb_root_cached *root = NULL; 4844dd1b841SLiam R. Howlett struct anon_vma *anon_vma = vma->anon_vma; 4854dd1b841SLiam R. Howlett struct file *file = vma->vm_file; 4864dd1b841SLiam R. Howlett bool remove_next = false; 4874dd1b841SLiam R. Howlett 4884dd1b841SLiam R. Howlett if (next && (vma != next) && (end == next->vm_end)) { 4894dd1b841SLiam R. Howlett remove_next = true; 4904dd1b841SLiam R. Howlett if (next->anon_vma && !vma->anon_vma) { 4914dd1b841SLiam R. Howlett int error; 4924dd1b841SLiam R. Howlett 4934dd1b841SLiam R. Howlett anon_vma = next->anon_vma; 4944dd1b841SLiam R. Howlett vma->anon_vma = anon_vma; 4954dd1b841SLiam R. Howlett error = anon_vma_clone(vma, next); 4964dd1b841SLiam R. Howlett if (error) 4974dd1b841SLiam R. Howlett return error; 4984dd1b841SLiam R. Howlett } 4994dd1b841SLiam R. Howlett } 5004dd1b841SLiam R. Howlett 5014dd1b841SLiam R. Howlett /* Not merging but overwriting any part of next is not handled. */ 5024dd1b841SLiam R. Howlett VM_BUG_ON(next && !remove_next && next != vma && end > next->vm_start); 5034dd1b841SLiam R. Howlett /* Only handles expanding */ 5044dd1b841SLiam R. Howlett VM_BUG_ON(vma->vm_start < start || vma->vm_end > end); 5054dd1b841SLiam R. Howlett 5063c441ab7SLiam R. Howlett if (vma_iter_prealloc(vmi)) 5074dd1b841SLiam R. Howlett goto nomem; 5084dd1b841SLiam R. Howlett 5094dd1b841SLiam R. Howlett vma_adjust_trans_huge(vma, start, end, 0); 5104dd1b841SLiam R. Howlett 5114dd1b841SLiam R. Howlett if (file) { 5124dd1b841SLiam R. Howlett mapping = file->f_mapping; 5134dd1b841SLiam R. Howlett root = &mapping->i_mmap; 5144dd1b841SLiam R. Howlett uprobe_munmap(vma, vma->vm_start, vma->vm_end); 5154dd1b841SLiam R. Howlett i_mmap_lock_write(mapping); 5164dd1b841SLiam R. Howlett } 5174dd1b841SLiam R. Howlett 5184dd1b841SLiam R. Howlett if (anon_vma) { 5194dd1b841SLiam R. Howlett anon_vma_lock_write(anon_vma); 5204dd1b841SLiam R. Howlett anon_vma_interval_tree_pre_update_vma(vma); 5214dd1b841SLiam R. Howlett } 5224dd1b841SLiam R. Howlett 5234dd1b841SLiam R. Howlett if (file) { 5244dd1b841SLiam R. Howlett flush_dcache_mmap_lock(mapping); 5254dd1b841SLiam R. Howlett vma_interval_tree_remove(vma, root); 5264dd1b841SLiam R. Howlett } 5274dd1b841SLiam R. Howlett 5284dd1b841SLiam R. Howlett vma->vm_start = start; 5294dd1b841SLiam R. Howlett vma->vm_end = end; 5304dd1b841SLiam R. Howlett vma->vm_pgoff = pgoff; 5313c441ab7SLiam R. Howlett vma_iter_store(vmi, vma); 5324dd1b841SLiam R. Howlett 5334dd1b841SLiam R. Howlett if (file) { 5344dd1b841SLiam R. Howlett vma_interval_tree_insert(vma, root); 5354dd1b841SLiam R. Howlett flush_dcache_mmap_unlock(mapping); 5364dd1b841SLiam R. Howlett } 5374dd1b841SLiam R. Howlett 5384dd1b841SLiam R. Howlett /* Expanding over the next vma */ 539763ecb03SLiam R. Howlett if (remove_next && file) { 5404dd1b841SLiam R. Howlett __remove_shared_vm_struct(next, file, mapping); 5414dd1b841SLiam R. Howlett } 5424dd1b841SLiam R. Howlett 5434dd1b841SLiam R. Howlett if (anon_vma) { 5444dd1b841SLiam R. Howlett anon_vma_interval_tree_post_update_vma(vma); 5454dd1b841SLiam R. Howlett anon_vma_unlock_write(anon_vma); 5464dd1b841SLiam R. Howlett } 5474dd1b841SLiam R. Howlett 5484dd1b841SLiam R. Howlett if (file) { 5494dd1b841SLiam R. Howlett i_mmap_unlock_write(mapping); 5504dd1b841SLiam R. Howlett uprobe_mmap(vma); 5514dd1b841SLiam R. Howlett } 5524dd1b841SLiam R. Howlett 5534dd1b841SLiam R. Howlett if (remove_next) { 5544dd1b841SLiam R. Howlett if (file) { 5554dd1b841SLiam R. Howlett uprobe_munmap(next, next->vm_start, next->vm_end); 5564dd1b841SLiam R. Howlett fput(file); 5574dd1b841SLiam R. Howlett } 5584dd1b841SLiam R. Howlett if (next->anon_vma) 5594dd1b841SLiam R. Howlett anon_vma_merge(vma, next); 5604dd1b841SLiam R. Howlett mm->map_count--; 5614dd1b841SLiam R. Howlett mpol_put(vma_policy(next)); 5624dd1b841SLiam R. Howlett vm_area_free(next); 5634dd1b841SLiam R. Howlett } 5644dd1b841SLiam R. Howlett 5654dd1b841SLiam R. Howlett validate_mm(mm); 5664dd1b841SLiam R. Howlett return 0; 5674dd1b841SLiam R. Howlett 5684dd1b841SLiam R. Howlett nomem: 5694dd1b841SLiam R. Howlett return -ENOMEM; 5704dd1b841SLiam R. Howlett } 5714dd1b841SLiam R. Howlett 5724dd1b841SLiam R. Howlett /* 5731da177e4SLinus Torvalds * We cannot adjust vm_start, vm_end, vm_pgoff fields of a vma that 5741da177e4SLinus Torvalds * is already present in an i_mmap tree without adjusting the tree. 5751da177e4SLinus Torvalds * The following helper function should be used when such adjustments 5761da177e4SLinus Torvalds * are necessary. The "insert" vma (if any) is to be inserted 5771da177e4SLinus Torvalds * before we drop the necessary locks. 5781da177e4SLinus Torvalds */ 579e86f15eeSAndrea Arcangeli int __vma_adjust(struct vm_area_struct *vma, unsigned long start, 580e86f15eeSAndrea Arcangeli unsigned long end, pgoff_t pgoff, struct vm_area_struct *insert, 581e86f15eeSAndrea Arcangeli struct vm_area_struct *expand) 5821da177e4SLinus Torvalds { 5831da177e4SLinus Torvalds struct mm_struct *mm = vma->vm_mm; 5841cd916d0SAndrew Morton struct vm_area_struct *next_next = NULL; /* uninit var warning */ 5851cd916d0SAndrew Morton struct vm_area_struct *next = find_vma(mm, vma->vm_end); 586524e00b3SLiam R. Howlett struct vm_area_struct *orig_vma = vma; 5871da177e4SLinus Torvalds struct address_space *mapping = NULL; 588f808c13fSDavidlohr Bueso struct rb_root_cached *root = NULL; 589012f1800SRik van Riel struct anon_vma *anon_vma = NULL; 5901da177e4SLinus Torvalds struct file *file = vma->vm_file; 591524e00b3SLiam R. Howlett bool vma_changed = false; 5921da177e4SLinus Torvalds long adjust_next = 0; 5931da177e4SLinus Torvalds int remove_next = 0; 594*fbcc3104SLiam R. Howlett VMA_ITERATOR(vmi, mm, 0); 595734537c9SKirill A. Shutemov struct vm_area_struct *exporter = NULL, *importer = NULL; 596287d97acSLinus Torvalds 597d4af56c5SLiam R. Howlett if (next && !insert) { 5981da177e4SLinus Torvalds if (end >= next->vm_end) { 5991da177e4SLinus Torvalds /* 6001da177e4SLinus Torvalds * vma expands, overlapping all the next, and 6011da177e4SLinus Torvalds * perhaps the one after too (mprotect case 6). 60286d12e47SAndrea Arcangeli * The only other cases that gets here are 603e86f15eeSAndrea Arcangeli * case 1, case 7 and case 8. 604e86f15eeSAndrea Arcangeli */ 605e86f15eeSAndrea Arcangeli if (next == expand) { 606e86f15eeSAndrea Arcangeli /* 607e86f15eeSAndrea Arcangeli * The only case where we don't expand "vma" 608e86f15eeSAndrea Arcangeli * and we expand "next" instead is case 8. 609e86f15eeSAndrea Arcangeli */ 610e86f15eeSAndrea Arcangeli VM_WARN_ON(end != next->vm_end); 611e86f15eeSAndrea Arcangeli /* 612e86f15eeSAndrea Arcangeli * remove_next == 3 means we're 613e86f15eeSAndrea Arcangeli * removing "vma" and that to do so we 614e86f15eeSAndrea Arcangeli * swapped "vma" and "next". 615e86f15eeSAndrea Arcangeli */ 616e86f15eeSAndrea Arcangeli remove_next = 3; 617e86f15eeSAndrea Arcangeli VM_WARN_ON(file != next->vm_file); 618e86f15eeSAndrea Arcangeli swap(vma, next); 619e86f15eeSAndrea Arcangeli } else { 620e86f15eeSAndrea Arcangeli VM_WARN_ON(expand != vma); 621e86f15eeSAndrea Arcangeli /* 622e86f15eeSAndrea Arcangeli * case 1, 6, 7, remove_next == 2 is case 6, 623e86f15eeSAndrea Arcangeli * remove_next == 1 is case 1 or 7. 6241da177e4SLinus Torvalds */ 625734537c9SKirill A. Shutemov remove_next = 1 + (end > next->vm_end); 626d4af56c5SLiam R. Howlett if (remove_next == 2) 627d4af56c5SLiam R. Howlett next_next = find_vma(mm, next->vm_end); 628d4af56c5SLiam R. Howlett 629e86f15eeSAndrea Arcangeli VM_WARN_ON(remove_next == 2 && 630763ecb03SLiam R. Howlett end != next_next->vm_end); 631e86f15eeSAndrea Arcangeli } 632e86f15eeSAndrea Arcangeli 633287d97acSLinus Torvalds exporter = next; 6341da177e4SLinus Torvalds importer = vma; 635734537c9SKirill A. Shutemov 636734537c9SKirill A. Shutemov /* 637734537c9SKirill A. Shutemov * If next doesn't have anon_vma, import from vma after 638734537c9SKirill A. Shutemov * next, if the vma overlaps with it. 639734537c9SKirill A. Shutemov */ 64097a42cd4SAndrea Arcangeli if (remove_next == 2 && !next->anon_vma) 641763ecb03SLiam R. Howlett exporter = next_next; 642734537c9SKirill A. Shutemov 6431da177e4SLinus Torvalds } else if (end > next->vm_start) { 6441da177e4SLinus Torvalds /* 6451da177e4SLinus Torvalds * vma expands, overlapping part of the next: 6461da177e4SLinus Torvalds * mprotect case 5 shifting the boundary up. 6471da177e4SLinus Torvalds */ 648f9d86a60SWei Yang adjust_next = (end - next->vm_start); 649287d97acSLinus Torvalds exporter = next; 6501da177e4SLinus Torvalds importer = vma; 651e86f15eeSAndrea Arcangeli VM_WARN_ON(expand != importer); 6521da177e4SLinus Torvalds } else if (end < vma->vm_end) { 6531da177e4SLinus Torvalds /* 6541da177e4SLinus Torvalds * vma shrinks, and !insert tells it's not 6551da177e4SLinus Torvalds * split_vma inserting another: so it must be 6561da177e4SLinus Torvalds * mprotect case 4 shifting the boundary down. 6571da177e4SLinus Torvalds */ 658f9d86a60SWei Yang adjust_next = -(vma->vm_end - end); 659287d97acSLinus Torvalds exporter = vma; 6601da177e4SLinus Torvalds importer = next; 661e86f15eeSAndrea Arcangeli VM_WARN_ON(expand != importer); 6621da177e4SLinus Torvalds } 6631da177e4SLinus Torvalds 6645beb4930SRik van Riel /* 6655beb4930SRik van Riel * Easily overlooked: when mprotect shifts the boundary, 6665beb4930SRik van Riel * make sure the expanding vma has anon_vma set if the 6675beb4930SRik van Riel * shrinking vma had, to cover any anon pages imported. 6685beb4930SRik van Riel */ 669287d97acSLinus Torvalds if (exporter && exporter->anon_vma && !importer->anon_vma) { 670c4ea95d7SDaniel Forrest int error; 671c4ea95d7SDaniel Forrest 672287d97acSLinus Torvalds importer->anon_vma = exporter->anon_vma; 673b800c91aSKonstantin Khlebnikov error = anon_vma_clone(importer, exporter); 6743fe89b3eSLeon Yu if (error) 675b800c91aSKonstantin Khlebnikov return error; 676b800c91aSKonstantin Khlebnikov } 6775beb4930SRik van Riel } 67837f9f559SKirill A. Shutemov 679*fbcc3104SLiam R. Howlett if (vma_iter_prealloc(&vmi)) 680d4af56c5SLiam R. Howlett return -ENOMEM; 681d4af56c5SLiam R. Howlett 682d4af56c5SLiam R. Howlett vma_adjust_trans_huge(orig_vma, start, end, adjust_next); 6831da177e4SLinus Torvalds if (file) { 6841da177e4SLinus Torvalds mapping = file->f_mapping; 6851da177e4SLinus Torvalds root = &mapping->i_mmap; 686cbc91f71SSrikar Dronamraju uprobe_munmap(vma, vma->vm_start, vma->vm_end); 687682968e0SSrikar Dronamraju 688682968e0SSrikar Dronamraju if (adjust_next) 68927ba0644SKirill A. Shutemov uprobe_munmap(next, next->vm_start, next->vm_end); 690682968e0SSrikar Dronamraju 69183cde9e8SDavidlohr Bueso i_mmap_lock_write(mapping); 692c154124fSLiam R. Howlett if (insert && insert->vm_file) { 6931da177e4SLinus Torvalds /* 6946b2dbba8SMichel Lespinasse * Put into interval tree now, so instantiated pages 6951da177e4SLinus Torvalds * are visible to arm/parisc __flush_dcache_page 6961da177e4SLinus Torvalds * throughout; but we cannot insert into address 6971da177e4SLinus Torvalds * space until vma start or end is updated. 6981da177e4SLinus Torvalds */ 699c154124fSLiam R. Howlett __vma_link_file(insert, insert->vm_file->f_mapping); 7001da177e4SLinus Torvalds } 7011da177e4SLinus Torvalds } 7021da177e4SLinus Torvalds 703012f1800SRik van Riel anon_vma = vma->anon_vma; 704bf181b9fSMichel Lespinasse if (!anon_vma && adjust_next) 705bf181b9fSMichel Lespinasse anon_vma = next->anon_vma; 706bf181b9fSMichel Lespinasse if (anon_vma) { 707e86f15eeSAndrea Arcangeli VM_WARN_ON(adjust_next && next->anon_vma && 708e86f15eeSAndrea Arcangeli anon_vma != next->anon_vma); 7094fc3f1d6SIngo Molnar anon_vma_lock_write(anon_vma); 710bf181b9fSMichel Lespinasse anon_vma_interval_tree_pre_update_vma(vma); 711bf181b9fSMichel Lespinasse if (adjust_next) 712bf181b9fSMichel Lespinasse anon_vma_interval_tree_pre_update_vma(next); 713bf181b9fSMichel Lespinasse } 714012f1800SRik van Riel 7150fc48a6eSWei Yang if (file) { 7161da177e4SLinus Torvalds flush_dcache_mmap_lock(mapping); 7176b2dbba8SMichel Lespinasse vma_interval_tree_remove(vma, root); 7181da177e4SLinus Torvalds if (adjust_next) 7196b2dbba8SMichel Lespinasse vma_interval_tree_remove(next, root); 7201da177e4SLinus Torvalds } 7211da177e4SLinus Torvalds 722d3737187SMichel Lespinasse if (start != vma->vm_start) { 7233b0e81a1SLiam R. Howlett if ((vma->vm_start < start) && 7243b0e81a1SLiam R. Howlett (!insert || (insert->vm_end != start))) { 725*fbcc3104SLiam R. Howlett vma_iter_clear(&vmi, vma->vm_start, start); 7263b0e81a1SLiam R. Howlett VM_WARN_ON(insert && insert->vm_start > vma->vm_start); 7273b0e81a1SLiam R. Howlett } else { 728524e00b3SLiam R. Howlett vma_changed = true; 7293b0e81a1SLiam R. Howlett } 7301da177e4SLinus Torvalds vma->vm_start = start; 731d3737187SMichel Lespinasse } 732d3737187SMichel Lespinasse if (end != vma->vm_end) { 7333b0e81a1SLiam R. Howlett if (vma->vm_end > end) { 7343b0e81a1SLiam R. Howlett if (!insert || (insert->vm_start != end)) { 735*fbcc3104SLiam R. Howlett vma_iter_clear(&vmi, end, vma->vm_end); 736*fbcc3104SLiam R. Howlett vma_iter_set(&vmi, vma->vm_end); 7373b0e81a1SLiam R. Howlett VM_WARN_ON(insert && 7383b0e81a1SLiam R. Howlett insert->vm_end < vma->vm_end); 7393b0e81a1SLiam R. Howlett } 7403b0e81a1SLiam R. Howlett } else { 741524e00b3SLiam R. Howlett vma_changed = true; 7423b0e81a1SLiam R. Howlett } 7431da177e4SLinus Torvalds vma->vm_end = end; 744d3737187SMichel Lespinasse } 745d4af56c5SLiam R. Howlett 746524e00b3SLiam R. Howlett if (vma_changed) 747*fbcc3104SLiam R. Howlett vma_iter_store(&vmi, vma); 748d4af56c5SLiam R. Howlett 7491da177e4SLinus Torvalds vma->vm_pgoff = pgoff; 7501da177e4SLinus Torvalds if (adjust_next) { 751f9d86a60SWei Yang next->vm_start += adjust_next; 752f9d86a60SWei Yang next->vm_pgoff += adjust_next >> PAGE_SHIFT; 753*fbcc3104SLiam R. Howlett vma_iter_store(&vmi, next); 7541da177e4SLinus Torvalds } 7551da177e4SLinus Torvalds 7560fc48a6eSWei Yang if (file) { 7571da177e4SLinus Torvalds if (adjust_next) 7586b2dbba8SMichel Lespinasse vma_interval_tree_insert(next, root); 7596b2dbba8SMichel Lespinasse vma_interval_tree_insert(vma, root); 7601da177e4SLinus Torvalds flush_dcache_mmap_unlock(mapping); 7611da177e4SLinus Torvalds } 7621da177e4SLinus Torvalds 763763ecb03SLiam R. Howlett if (remove_next && file) { 7641da177e4SLinus Torvalds __remove_shared_vm_struct(next, file, mapping); 765d4af56c5SLiam R. Howlett if (remove_next == 2) 766d4af56c5SLiam R. Howlett __remove_shared_vm_struct(next_next, file, mapping); 7671da177e4SLinus Torvalds } else if (insert) { 7681da177e4SLinus Torvalds /* 7691da177e4SLinus Torvalds * split_vma has split insert from vma, and needs 7701da177e4SLinus Torvalds * us to insert it before dropping the locks 7711da177e4SLinus Torvalds * (it may either follow vma or precede it). 7721da177e4SLinus Torvalds */ 773*fbcc3104SLiam R. Howlett vma_iter_store(&vmi, insert); 774763ecb03SLiam R. Howlett mm->map_count++; 7751da177e4SLinus Torvalds } 7761da177e4SLinus Torvalds 777bf181b9fSMichel Lespinasse if (anon_vma) { 778bf181b9fSMichel Lespinasse anon_vma_interval_tree_post_update_vma(vma); 779bf181b9fSMichel Lespinasse if (adjust_next) 780bf181b9fSMichel Lespinasse anon_vma_interval_tree_post_update_vma(next); 78108b52706SKonstantin Khlebnikov anon_vma_unlock_write(anon_vma); 782bf181b9fSMichel Lespinasse } 7831da177e4SLinus Torvalds 7840fc48a6eSWei Yang if (file) { 785808fbdbeSWei Yang i_mmap_unlock_write(mapping); 7867b2d81d4SIngo Molnar uprobe_mmap(vma); 7872b144498SSrikar Dronamraju 7882b144498SSrikar Dronamraju if (adjust_next) 7897b2d81d4SIngo Molnar uprobe_mmap(next); 7902b144498SSrikar Dronamraju } 7912b144498SSrikar Dronamraju 7921da177e4SLinus Torvalds if (remove_next) { 793d4af56c5SLiam R. Howlett again: 794925d1c40SMatt Helsley if (file) { 795cbc91f71SSrikar Dronamraju uprobe_munmap(next, next->vm_start, next->vm_end); 7961da177e4SLinus Torvalds fput(file); 797925d1c40SMatt Helsley } 7985beb4930SRik van Riel if (next->anon_vma) 7995beb4930SRik van Riel anon_vma_merge(vma, next); 8001da177e4SLinus Torvalds mm->map_count--; 8013964acd0SOleg Nesterov mpol_put(vma_policy(next)); 802524e00b3SLiam R. Howlett if (remove_next != 2) 803524e00b3SLiam R. Howlett BUG_ON(vma->vm_end < next->vm_end); 8043928d4f5SLinus Torvalds vm_area_free(next); 805524e00b3SLiam R. Howlett 8061da177e4SLinus Torvalds /* 8071da177e4SLinus Torvalds * In mprotect's case 6 (see comments on vma_merge), 808763ecb03SLiam R. Howlett * we must remove next_next too. 8091da177e4SLinus Torvalds */ 810734537c9SKirill A. Shutemov if (remove_next == 2) { 811734537c9SKirill A. Shutemov remove_next = 1; 812763ecb03SLiam R. Howlett next = next_next; 8131da177e4SLinus Torvalds goto again; 814fb8c41e9SAndrea Arcangeli } 8151da177e4SLinus Torvalds } 8162b144498SSrikar Dronamraju if (insert && file) 8177b2d81d4SIngo Molnar uprobe_mmap(insert); 8181da177e4SLinus Torvalds 819*fbcc3104SLiam R. Howlett vma_iter_free(&vmi); 8201da177e4SLinus Torvalds validate_mm(mm); 821763ecb03SLiam R. Howlett 8225beb4930SRik van Riel return 0; 8231da177e4SLinus Torvalds } 8241da177e4SLinus Torvalds 8251da177e4SLinus Torvalds /* 8261da177e4SLinus Torvalds * If the vma has a ->close operation then the driver probably needs to release 8271da177e4SLinus Torvalds * per-vma resources, so we don't attempt to merge those. 8281da177e4SLinus Torvalds */ 8291da177e4SLinus Torvalds static inline int is_mergeable_vma(struct vm_area_struct *vma, 83019a809afSAndrea Arcangeli struct file *file, unsigned long vm_flags, 8319a10064fSColin Cross struct vm_userfaultfd_ctx vm_userfaultfd_ctx, 8325c26f6acSSuren Baghdasaryan struct anon_vma_name *anon_name) 8331da177e4SLinus Torvalds { 83434228d47SCyrill Gorcunov /* 83534228d47SCyrill Gorcunov * VM_SOFTDIRTY should not prevent from VMA merging, if we 83634228d47SCyrill Gorcunov * match the flags but dirty bit -- the caller should mark 83734228d47SCyrill Gorcunov * merged VMA as dirty. If dirty bit won't be excluded from 8388bb4e7a2SWei Yang * comparison, we increase pressure on the memory system forcing 83934228d47SCyrill Gorcunov * the kernel to generate new VMAs when old one could be 84034228d47SCyrill Gorcunov * extended instead. 84134228d47SCyrill Gorcunov */ 84234228d47SCyrill Gorcunov if ((vma->vm_flags ^ vm_flags) & ~VM_SOFTDIRTY) 8431da177e4SLinus Torvalds return 0; 8441da177e4SLinus Torvalds if (vma->vm_file != file) 8451da177e4SLinus Torvalds return 0; 8461da177e4SLinus Torvalds if (vma->vm_ops && vma->vm_ops->close) 8471da177e4SLinus Torvalds return 0; 84819a809afSAndrea Arcangeli if (!is_mergeable_vm_userfaultfd_ctx(vma, vm_userfaultfd_ctx)) 84919a809afSAndrea Arcangeli return 0; 8505c26f6acSSuren Baghdasaryan if (!anon_vma_name_eq(anon_vma_name(vma), anon_name)) 8519a10064fSColin Cross return 0; 8521da177e4SLinus Torvalds return 1; 8531da177e4SLinus Torvalds } 8541da177e4SLinus Torvalds 8551da177e4SLinus Torvalds static inline int is_mergeable_anon_vma(struct anon_vma *anon_vma1, 856965f55deSShaohua Li struct anon_vma *anon_vma2, 857965f55deSShaohua Li struct vm_area_struct *vma) 8581da177e4SLinus Torvalds { 859965f55deSShaohua Li /* 860965f55deSShaohua Li * The list_is_singular() test is to avoid merging VMA cloned from 861965f55deSShaohua Li * parents. This can improve scalability caused by anon_vma lock. 862965f55deSShaohua Li */ 863965f55deSShaohua Li if ((!anon_vma1 || !anon_vma2) && (!vma || 864965f55deSShaohua Li list_is_singular(&vma->anon_vma_chain))) 865965f55deSShaohua Li return 1; 866965f55deSShaohua Li return anon_vma1 == anon_vma2; 8671da177e4SLinus Torvalds } 8681da177e4SLinus Torvalds 8691da177e4SLinus Torvalds /* 8701da177e4SLinus Torvalds * Return true if we can merge this (vm_flags,anon_vma,file,vm_pgoff) 8711da177e4SLinus Torvalds * in front of (at a lower virtual address and file offset than) the vma. 8721da177e4SLinus Torvalds * 8731da177e4SLinus Torvalds * We cannot merge two vmas if they have differently assigned (non-NULL) 8741da177e4SLinus Torvalds * anon_vmas, nor if same anon_vma is assigned but offsets incompatible. 8751da177e4SLinus Torvalds * 8761da177e4SLinus Torvalds * We don't check here for the merged mmap wrapping around the end of pagecache 87745e55300SPeter Collingbourne * indices (16TB on ia32) because do_mmap() does not permit mmap's which 8781da177e4SLinus Torvalds * wrap, nor mmaps which cover the final page at index -1UL. 8791da177e4SLinus Torvalds */ 8801da177e4SLinus Torvalds static int 8811da177e4SLinus Torvalds can_vma_merge_before(struct vm_area_struct *vma, unsigned long vm_flags, 88219a809afSAndrea Arcangeli struct anon_vma *anon_vma, struct file *file, 88319a809afSAndrea Arcangeli pgoff_t vm_pgoff, 8849a10064fSColin Cross struct vm_userfaultfd_ctx vm_userfaultfd_ctx, 8855c26f6acSSuren Baghdasaryan struct anon_vma_name *anon_name) 8861da177e4SLinus Torvalds { 8879a10064fSColin Cross if (is_mergeable_vma(vma, file, vm_flags, vm_userfaultfd_ctx, anon_name) && 888965f55deSShaohua Li is_mergeable_anon_vma(anon_vma, vma->anon_vma, vma)) { 8891da177e4SLinus Torvalds if (vma->vm_pgoff == vm_pgoff) 8901da177e4SLinus Torvalds return 1; 8911da177e4SLinus Torvalds } 8921da177e4SLinus Torvalds return 0; 8931da177e4SLinus Torvalds } 8941da177e4SLinus Torvalds 8951da177e4SLinus Torvalds /* 8961da177e4SLinus Torvalds * Return true if we can merge this (vm_flags,anon_vma,file,vm_pgoff) 8971da177e4SLinus Torvalds * beyond (at a higher virtual address and file offset than) the vma. 8981da177e4SLinus Torvalds * 8991da177e4SLinus Torvalds * We cannot merge two vmas if they have differently assigned (non-NULL) 9001da177e4SLinus Torvalds * anon_vmas, nor if same anon_vma is assigned but offsets incompatible. 9011da177e4SLinus Torvalds */ 9021da177e4SLinus Torvalds static int 9031da177e4SLinus Torvalds can_vma_merge_after(struct vm_area_struct *vma, unsigned long vm_flags, 90419a809afSAndrea Arcangeli struct anon_vma *anon_vma, struct file *file, 90519a809afSAndrea Arcangeli pgoff_t vm_pgoff, 9069a10064fSColin Cross struct vm_userfaultfd_ctx vm_userfaultfd_ctx, 9075c26f6acSSuren Baghdasaryan struct anon_vma_name *anon_name) 9081da177e4SLinus Torvalds { 9099a10064fSColin Cross if (is_mergeable_vma(vma, file, vm_flags, vm_userfaultfd_ctx, anon_name) && 910965f55deSShaohua Li is_mergeable_anon_vma(anon_vma, vma->anon_vma, vma)) { 9111da177e4SLinus Torvalds pgoff_t vm_pglen; 912d6e93217SLibin vm_pglen = vma_pages(vma); 9131da177e4SLinus Torvalds if (vma->vm_pgoff + vm_pglen == vm_pgoff) 9141da177e4SLinus Torvalds return 1; 9151da177e4SLinus Torvalds } 9161da177e4SLinus Torvalds return 0; 9171da177e4SLinus Torvalds } 9181da177e4SLinus Torvalds 9191da177e4SLinus Torvalds /* 9209a10064fSColin Cross * Given a mapping request (addr,end,vm_flags,file,pgoff,anon_name), 9219a10064fSColin Cross * figure out whether that can be merged with its predecessor or its 9229a10064fSColin Cross * successor. Or both (it neatly fills a hole). 9231da177e4SLinus Torvalds * 9241da177e4SLinus Torvalds * In most cases - when called for mmap, brk or mremap - [addr,end) is 9251da177e4SLinus Torvalds * certain not to be mapped by the time vma_merge is called; but when 9261da177e4SLinus Torvalds * called for mprotect, it is certain to be already mapped (either at 9271da177e4SLinus Torvalds * an offset within prev, or at the start of next), and the flags of 9281da177e4SLinus Torvalds * this area are about to be changed to vm_flags - and the no-change 9291da177e4SLinus Torvalds * case has already been eliminated. 9301da177e4SLinus Torvalds * 9311da177e4SLinus Torvalds * The following mprotect cases have to be considered, where AAAA is 9321da177e4SLinus Torvalds * the area passed down from mprotect_fixup, never extending beyond one 9331da177e4SLinus Torvalds * vma, PPPPPP is the prev vma specified, and NNNNNN the next vma after: 9341da177e4SLinus Torvalds * 9355d42ab29SWei Yang * AAAA AAAA AAAA 9365d42ab29SWei Yang * PPPPPPNNNNNN PPPPPPNNNNNN PPPPPPNNNNNN 9375d42ab29SWei Yang * cannot merge might become might become 9385d42ab29SWei Yang * PPNNNNNNNNNN PPPPPPPPPPNN 9395d42ab29SWei Yang * mmap, brk or case 4 below case 5 below 9405d42ab29SWei Yang * mremap move: 9415d42ab29SWei Yang * AAAA AAAA 9425d42ab29SWei Yang * PPPP NNNN PPPPNNNNXXXX 9435d42ab29SWei Yang * might become might become 9445d42ab29SWei Yang * PPPPPPPPPPPP 1 or PPPPPPPPPPPP 6 or 9455d42ab29SWei Yang * PPPPPPPPNNNN 2 or PPPPPPPPXXXX 7 or 9465d42ab29SWei Yang * PPPPNNNNNNNN 3 PPPPXXXXXXXX 8 9471da177e4SLinus Torvalds * 9488bb4e7a2SWei Yang * It is important for case 8 that the vma NNNN overlapping the 949e86f15eeSAndrea Arcangeli * region AAAA is never going to extended over XXXX. Instead XXXX must 950e86f15eeSAndrea Arcangeli * be extended in region AAAA and NNNN must be removed. This way in 951e86f15eeSAndrea Arcangeli * all cases where vma_merge succeeds, the moment vma_adjust drops the 952e86f15eeSAndrea Arcangeli * rmap_locks, the properties of the merged vma will be already 953e86f15eeSAndrea Arcangeli * correct for the whole merged range. Some of those properties like 954e86f15eeSAndrea Arcangeli * vm_page_prot/vm_flags may be accessed by rmap_walks and they must 955e86f15eeSAndrea Arcangeli * be correct for the whole merged range immediately after the 956e86f15eeSAndrea Arcangeli * rmap_locks are released. Otherwise if XXXX would be removed and 957e86f15eeSAndrea Arcangeli * NNNN would be extended over the XXXX range, remove_migration_ptes 958e86f15eeSAndrea Arcangeli * or other rmap walkers (if working on addresses beyond the "end" 959e86f15eeSAndrea Arcangeli * parameter) may establish ptes with the wrong permissions of NNNN 960e86f15eeSAndrea Arcangeli * instead of the right permissions of XXXX. 9611da177e4SLinus Torvalds */ 9629760ebffSLiam R. Howlett struct vm_area_struct *vma_merge(struct vma_iterator *vmi, struct mm_struct *mm, 9631da177e4SLinus Torvalds struct vm_area_struct *prev, unsigned long addr, 9641da177e4SLinus Torvalds unsigned long end, unsigned long vm_flags, 9651da177e4SLinus Torvalds struct anon_vma *anon_vma, struct file *file, 96619a809afSAndrea Arcangeli pgoff_t pgoff, struct mempolicy *policy, 9679a10064fSColin Cross struct vm_userfaultfd_ctx vm_userfaultfd_ctx, 9685c26f6acSSuren Baghdasaryan struct anon_vma_name *anon_name) 9691da177e4SLinus Torvalds { 9701da177e4SLinus Torvalds pgoff_t pglen = (end - addr) >> PAGE_SHIFT; 9719760ebffSLiam R. Howlett struct vm_area_struct *mid, *next, *res = NULL; 972eef19944SJakub Matěna int err = -1; 973eef19944SJakub Matěna bool merge_prev = false; 974eef19944SJakub Matěna bool merge_next = false; 9751da177e4SLinus Torvalds 9761da177e4SLinus Torvalds /* 9771da177e4SLinus Torvalds * We later require that vma->vm_flags == vm_flags, 9781da177e4SLinus Torvalds * so this tests vma->vm_flags & VM_SPECIAL, too. 9791da177e4SLinus Torvalds */ 9801da177e4SLinus Torvalds if (vm_flags & VM_SPECIAL) 9811da177e4SLinus Torvalds return NULL; 9821da177e4SLinus Torvalds 983763ecb03SLiam R. Howlett next = find_vma(mm, prev ? prev->vm_end : 0); 984eef19944SJakub Matěna mid = next; 985eef19944SJakub Matěna if (next && next->vm_end == end) /* cases 6, 7, 8 */ 986763ecb03SLiam R. Howlett next = find_vma(mm, next->vm_end); 9871da177e4SLinus Torvalds 988e86f15eeSAndrea Arcangeli /* verify some invariant that must be enforced by the caller */ 989e86f15eeSAndrea Arcangeli VM_WARN_ON(prev && addr <= prev->vm_start); 990eef19944SJakub Matěna VM_WARN_ON(mid && end > mid->vm_end); 991e86f15eeSAndrea Arcangeli VM_WARN_ON(addr >= end); 992e86f15eeSAndrea Arcangeli 993eef19944SJakub Matěna /* Can we merge the predecessor? */ 9941da177e4SLinus Torvalds if (prev && prev->vm_end == addr && 9951da177e4SLinus Torvalds mpol_equal(vma_policy(prev), policy) && 9961da177e4SLinus Torvalds can_vma_merge_after(prev, vm_flags, 99719a809afSAndrea Arcangeli anon_vma, file, pgoff, 9989a10064fSColin Cross vm_userfaultfd_ctx, anon_name)) { 999eef19944SJakub Matěna merge_prev = true; 10001da177e4SLinus Torvalds } 1001eef19944SJakub Matěna /* Can we merge the successor? */ 10021da177e4SLinus Torvalds if (next && end == next->vm_start && 10031da177e4SLinus Torvalds mpol_equal(policy, vma_policy(next)) && 10041da177e4SLinus Torvalds can_vma_merge_before(next, vm_flags, 100519a809afSAndrea Arcangeli anon_vma, file, pgoff+pglen, 10069a10064fSColin Cross vm_userfaultfd_ctx, anon_name)) { 1007eef19944SJakub Matěna merge_next = true; 1008eef19944SJakub Matěna } 1009eef19944SJakub Matěna /* Can we merge both the predecessor and the successor? */ 1010eef19944SJakub Matěna if (merge_prev && merge_next && 1011eef19944SJakub Matěna is_mergeable_anon_vma(prev->anon_vma, 1012eef19944SJakub Matěna next->anon_vma, NULL)) { /* cases 1, 6 */ 1013eef19944SJakub Matěna err = __vma_adjust(prev, prev->vm_start, 1014eef19944SJakub Matěna next->vm_end, prev->vm_pgoff, NULL, 1015eef19944SJakub Matěna prev); 1016eef19944SJakub Matěna res = prev; 1017eef19944SJakub Matěna } else if (merge_prev) { /* cases 2, 5, 7 */ 1018eef19944SJakub Matěna err = __vma_adjust(prev, prev->vm_start, 1019eef19944SJakub Matěna end, prev->vm_pgoff, NULL, prev); 1020eef19944SJakub Matěna res = prev; 1021eef19944SJakub Matěna } else if (merge_next) { 10221da177e4SLinus Torvalds if (prev && addr < prev->vm_end) /* case 4 */ 1023e86f15eeSAndrea Arcangeli err = __vma_adjust(prev, prev->vm_start, 1024e86f15eeSAndrea Arcangeli addr, prev->vm_pgoff, NULL, next); 1025eef19944SJakub Matěna else /* cases 3, 8 */ 1026eef19944SJakub Matěna err = __vma_adjust(mid, addr, next->vm_end, 1027e86f15eeSAndrea Arcangeli next->vm_pgoff - pglen, NULL, next); 1028eef19944SJakub Matěna res = next; 10291da177e4SLinus Torvalds } 10301da177e4SLinus Torvalds 1031eef19944SJakub Matěna /* 1032eef19944SJakub Matěna * Cannot merge with predecessor or successor or error in __vma_adjust? 1033eef19944SJakub Matěna */ 1034eef19944SJakub Matěna if (err) 10351da177e4SLinus Torvalds return NULL; 1036eef19944SJakub Matěna khugepaged_enter_vma(res, vm_flags); 10371da177e4SLinus Torvalds 10389760ebffSLiam R. Howlett if (res) 1039f2ebfe43SLiam R. Howlett vma_iter_set(vmi, end); 1040f2ebfe43SLiam R. Howlett 10419760ebffSLiam R. Howlett return res; 1042f2ebfe43SLiam R. Howlett } 1043f2ebfe43SLiam R. Howlett 10441da177e4SLinus Torvalds /* 1045b4f315b4SEthon Paul * Rough compatibility check to quickly see if it's even worth looking 1046d0e9fe17SLinus Torvalds * at sharing an anon_vma. 1047d0e9fe17SLinus Torvalds * 1048d0e9fe17SLinus Torvalds * They need to have the same vm_file, and the flags can only differ 1049d0e9fe17SLinus Torvalds * in things that mprotect may change. 1050d0e9fe17SLinus Torvalds * 1051d0e9fe17SLinus Torvalds * NOTE! The fact that we share an anon_vma doesn't _have_ to mean that 1052d0e9fe17SLinus Torvalds * we can merge the two vma's. For example, we refuse to merge a vma if 1053d0e9fe17SLinus Torvalds * there is a vm_ops->close() function, because that indicates that the 1054d0e9fe17SLinus Torvalds * driver is doing some kind of reference counting. But that doesn't 1055d0e9fe17SLinus Torvalds * really matter for the anon_vma sharing case. 1056d0e9fe17SLinus Torvalds */ 1057d0e9fe17SLinus Torvalds static int anon_vma_compatible(struct vm_area_struct *a, struct vm_area_struct *b) 1058d0e9fe17SLinus Torvalds { 1059d0e9fe17SLinus Torvalds return a->vm_end == b->vm_start && 1060d0e9fe17SLinus Torvalds mpol_equal(vma_policy(a), vma_policy(b)) && 1061d0e9fe17SLinus Torvalds a->vm_file == b->vm_file && 10626cb4d9a2SAnshuman Khandual !((a->vm_flags ^ b->vm_flags) & ~(VM_ACCESS_FLAGS | VM_SOFTDIRTY)) && 1063d0e9fe17SLinus Torvalds b->vm_pgoff == a->vm_pgoff + ((b->vm_start - a->vm_start) >> PAGE_SHIFT); 1064d0e9fe17SLinus Torvalds } 1065d0e9fe17SLinus Torvalds 1066d0e9fe17SLinus Torvalds /* 1067d0e9fe17SLinus Torvalds * Do some basic sanity checking to see if we can re-use the anon_vma 1068d0e9fe17SLinus Torvalds * from 'old'. The 'a'/'b' vma's are in VM order - one of them will be 1069d0e9fe17SLinus Torvalds * the same as 'old', the other will be the new one that is trying 1070d0e9fe17SLinus Torvalds * to share the anon_vma. 1071d0e9fe17SLinus Torvalds * 10725b449489SFlorian Rommel * NOTE! This runs with mmap_lock held for reading, so it is possible that 1073d0e9fe17SLinus Torvalds * the anon_vma of 'old' is concurrently in the process of being set up 1074d0e9fe17SLinus Torvalds * by another page fault trying to merge _that_. But that's ok: if it 1075d0e9fe17SLinus Torvalds * is being set up, that automatically means that it will be a singleton 1076d0e9fe17SLinus Torvalds * acceptable for merging, so we can do all of this optimistically. But 10774db0c3c2SJason Low * we do that READ_ONCE() to make sure that we never re-load the pointer. 1078d0e9fe17SLinus Torvalds * 1079d0e9fe17SLinus Torvalds * IOW: that the "list_is_singular()" test on the anon_vma_chain only 1080d0e9fe17SLinus Torvalds * matters for the 'stable anon_vma' case (ie the thing we want to avoid 1081d0e9fe17SLinus Torvalds * is to return an anon_vma that is "complex" due to having gone through 1082d0e9fe17SLinus Torvalds * a fork). 1083d0e9fe17SLinus Torvalds * 1084d0e9fe17SLinus Torvalds * We also make sure that the two vma's are compatible (adjacent, 1085d0e9fe17SLinus Torvalds * and with the same memory policies). That's all stable, even with just 10865b449489SFlorian Rommel * a read lock on the mmap_lock. 1087d0e9fe17SLinus Torvalds */ 1088d0e9fe17SLinus Torvalds static struct anon_vma *reusable_anon_vma(struct vm_area_struct *old, struct vm_area_struct *a, struct vm_area_struct *b) 1089d0e9fe17SLinus Torvalds { 1090d0e9fe17SLinus Torvalds if (anon_vma_compatible(a, b)) { 10914db0c3c2SJason Low struct anon_vma *anon_vma = READ_ONCE(old->anon_vma); 1092d0e9fe17SLinus Torvalds 1093d0e9fe17SLinus Torvalds if (anon_vma && list_is_singular(&old->anon_vma_chain)) 1094d0e9fe17SLinus Torvalds return anon_vma; 1095d0e9fe17SLinus Torvalds } 1096d0e9fe17SLinus Torvalds return NULL; 1097d0e9fe17SLinus Torvalds } 1098d0e9fe17SLinus Torvalds 1099d0e9fe17SLinus Torvalds /* 11001da177e4SLinus Torvalds * find_mergeable_anon_vma is used by anon_vma_prepare, to check 11011da177e4SLinus Torvalds * neighbouring vmas for a suitable anon_vma, before it goes off 11021da177e4SLinus Torvalds * to allocate a new anon_vma. It checks because a repetitive 11031da177e4SLinus Torvalds * sequence of mprotects and faults may otherwise lead to distinct 11041da177e4SLinus Torvalds * anon_vmas being allocated, preventing vma merge in subsequent 11051da177e4SLinus Torvalds * mprotect. 11061da177e4SLinus Torvalds */ 11071da177e4SLinus Torvalds struct anon_vma *find_mergeable_anon_vma(struct vm_area_struct *vma) 11081da177e4SLinus Torvalds { 1109763ecb03SLiam R. Howlett MA_STATE(mas, &vma->vm_mm->mm_mt, vma->vm_end, vma->vm_end); 1110a67c8caaSMiaohe Lin struct anon_vma *anon_vma = NULL; 1111763ecb03SLiam R. Howlett struct vm_area_struct *prev, *next; 11121da177e4SLinus Torvalds 1113a67c8caaSMiaohe Lin /* Try next first. */ 1114763ecb03SLiam R. Howlett next = mas_walk(&mas); 1115763ecb03SLiam R. Howlett if (next) { 1116763ecb03SLiam R. Howlett anon_vma = reusable_anon_vma(next, vma, next); 1117d0e9fe17SLinus Torvalds if (anon_vma) 1118d0e9fe17SLinus Torvalds return anon_vma; 1119a67c8caaSMiaohe Lin } 11201da177e4SLinus Torvalds 1121763ecb03SLiam R. Howlett prev = mas_prev(&mas, 0); 1122763ecb03SLiam R. Howlett VM_BUG_ON_VMA(prev != vma, vma); 1123763ecb03SLiam R. Howlett prev = mas_prev(&mas, 0); 1124a67c8caaSMiaohe Lin /* Try prev next. */ 1125763ecb03SLiam R. Howlett if (prev) 1126763ecb03SLiam R. Howlett anon_vma = reusable_anon_vma(prev, prev, vma); 1127a67c8caaSMiaohe Lin 11281da177e4SLinus Torvalds /* 1129a67c8caaSMiaohe Lin * We might reach here with anon_vma == NULL if we can't find 1130a67c8caaSMiaohe Lin * any reusable anon_vma. 11311da177e4SLinus Torvalds * There's no absolute need to look only at touching neighbours: 11321da177e4SLinus Torvalds * we could search further afield for "compatible" anon_vmas. 11331da177e4SLinus Torvalds * But it would probably just be a waste of time searching, 11341da177e4SLinus Torvalds * or lead to too many vmas hanging off the same anon_vma. 11351da177e4SLinus Torvalds * We're trying to allow mprotect remerging later on, 11361da177e4SLinus Torvalds * not trying to minimize memory used for anon_vmas. 11371da177e4SLinus Torvalds */ 1138a67c8caaSMiaohe Lin return anon_vma; 11391da177e4SLinus Torvalds } 11401da177e4SLinus Torvalds 11411da177e4SLinus Torvalds /* 114240401530SAl Viro * If a hint addr is less than mmap_min_addr change hint to be as 114340401530SAl Viro * low as possible but still greater than mmap_min_addr 114440401530SAl Viro */ 114540401530SAl Viro static inline unsigned long round_hint_to_min(unsigned long hint) 114640401530SAl Viro { 114740401530SAl Viro hint &= PAGE_MASK; 114840401530SAl Viro if (((void *)hint != NULL) && 114940401530SAl Viro (hint < mmap_min_addr)) 115040401530SAl Viro return PAGE_ALIGN(mmap_min_addr); 115140401530SAl Viro return hint; 115240401530SAl Viro } 115340401530SAl Viro 11546aeb2542SMike Rapoport int mlock_future_check(struct mm_struct *mm, unsigned long flags, 1155363ee17fSDavidlohr Bueso unsigned long len) 1156363ee17fSDavidlohr Bueso { 1157363ee17fSDavidlohr Bueso unsigned long locked, lock_limit; 1158363ee17fSDavidlohr Bueso 1159363ee17fSDavidlohr Bueso /* mlock MCL_FUTURE? */ 1160363ee17fSDavidlohr Bueso if (flags & VM_LOCKED) { 1161363ee17fSDavidlohr Bueso locked = len >> PAGE_SHIFT; 1162363ee17fSDavidlohr Bueso locked += mm->locked_vm; 1163363ee17fSDavidlohr Bueso lock_limit = rlimit(RLIMIT_MEMLOCK); 1164363ee17fSDavidlohr Bueso lock_limit >>= PAGE_SHIFT; 1165363ee17fSDavidlohr Bueso if (locked > lock_limit && !capable(CAP_IPC_LOCK)) 1166363ee17fSDavidlohr Bueso return -EAGAIN; 1167363ee17fSDavidlohr Bueso } 1168363ee17fSDavidlohr Bueso return 0; 1169363ee17fSDavidlohr Bueso } 1170363ee17fSDavidlohr Bueso 1171be83bbf8SLinus Torvalds static inline u64 file_mmap_size_max(struct file *file, struct inode *inode) 1172be83bbf8SLinus Torvalds { 1173be83bbf8SLinus Torvalds if (S_ISREG(inode->i_mode)) 1174423913adSLinus Torvalds return MAX_LFS_FILESIZE; 1175be83bbf8SLinus Torvalds 1176be83bbf8SLinus Torvalds if (S_ISBLK(inode->i_mode)) 1177be83bbf8SLinus Torvalds return MAX_LFS_FILESIZE; 1178be83bbf8SLinus Torvalds 117976f34950SIvan Khoronzhuk if (S_ISSOCK(inode->i_mode)) 118076f34950SIvan Khoronzhuk return MAX_LFS_FILESIZE; 118176f34950SIvan Khoronzhuk 1182be83bbf8SLinus Torvalds /* Special "we do even unsigned file positions" case */ 1183be83bbf8SLinus Torvalds if (file->f_mode & FMODE_UNSIGNED_OFFSET) 1184be83bbf8SLinus Torvalds return 0; 1185be83bbf8SLinus Torvalds 1186be83bbf8SLinus Torvalds /* Yes, random drivers might want more. But I'm tired of buggy drivers */ 1187be83bbf8SLinus Torvalds return ULONG_MAX; 1188be83bbf8SLinus Torvalds } 1189be83bbf8SLinus Torvalds 1190be83bbf8SLinus Torvalds static inline bool file_mmap_ok(struct file *file, struct inode *inode, 1191be83bbf8SLinus Torvalds unsigned long pgoff, unsigned long len) 1192be83bbf8SLinus Torvalds { 1193be83bbf8SLinus Torvalds u64 maxsize = file_mmap_size_max(file, inode); 1194be83bbf8SLinus Torvalds 1195be83bbf8SLinus Torvalds if (maxsize && len > maxsize) 1196be83bbf8SLinus Torvalds return false; 1197be83bbf8SLinus Torvalds maxsize -= len; 1198be83bbf8SLinus Torvalds if (pgoff > maxsize >> PAGE_SHIFT) 1199be83bbf8SLinus Torvalds return false; 1200be83bbf8SLinus Torvalds return true; 1201be83bbf8SLinus Torvalds } 1202be83bbf8SLinus Torvalds 120340401530SAl Viro /* 12043e4e28c5SMichel Lespinasse * The caller must write-lock current->mm->mmap_lock. 12051da177e4SLinus Torvalds */ 12061fcfd8dbSOleg Nesterov unsigned long do_mmap(struct file *file, unsigned long addr, 12071da177e4SLinus Torvalds unsigned long len, unsigned long prot, 120845e55300SPeter Collingbourne unsigned long flags, unsigned long pgoff, 120945e55300SPeter Collingbourne unsigned long *populate, struct list_head *uf) 12101da177e4SLinus Torvalds { 12111da177e4SLinus Torvalds struct mm_struct *mm = current->mm; 121245e55300SPeter Collingbourne vm_flags_t vm_flags; 121362b5f7d0SDave Hansen int pkey = 0; 12141da177e4SLinus Torvalds 1215524e00b3SLiam R. Howlett validate_mm(mm); 121641badc15SMichel Lespinasse *populate = 0; 1217bebeb3d6SMichel Lespinasse 1218e37609bbSPiotr Kwapulinski if (!len) 1219e37609bbSPiotr Kwapulinski return -EINVAL; 1220e37609bbSPiotr Kwapulinski 12211da177e4SLinus Torvalds /* 12221da177e4SLinus Torvalds * Does the application expect PROT_READ to imply PROT_EXEC? 12231da177e4SLinus Torvalds * 12241da177e4SLinus Torvalds * (the exception is when the underlying filesystem is noexec 12251da177e4SLinus Torvalds * mounted, in which case we dont add PROT_EXEC.) 12261da177e4SLinus Torvalds */ 12271da177e4SLinus Torvalds if ((prot & PROT_READ) && (current->personality & READ_IMPLIES_EXEC)) 122890f8572bSEric W. Biederman if (!(file && path_noexec(&file->f_path))) 12291da177e4SLinus Torvalds prot |= PROT_EXEC; 12301da177e4SLinus Torvalds 1231a4ff8e86SMichal Hocko /* force arch specific MAP_FIXED handling in get_unmapped_area */ 1232a4ff8e86SMichal Hocko if (flags & MAP_FIXED_NOREPLACE) 1233a4ff8e86SMichal Hocko flags |= MAP_FIXED; 1234a4ff8e86SMichal Hocko 12357cd94146SEric Paris if (!(flags & MAP_FIXED)) 12367cd94146SEric Paris addr = round_hint_to_min(addr); 12377cd94146SEric Paris 12381da177e4SLinus Torvalds /* Careful about overflows.. */ 12391da177e4SLinus Torvalds len = PAGE_ALIGN(len); 12409206de95SAl Viro if (!len) 12411da177e4SLinus Torvalds return -ENOMEM; 12421da177e4SLinus Torvalds 12431da177e4SLinus Torvalds /* offset overflow? */ 12441da177e4SLinus Torvalds if ((pgoff + (len >> PAGE_SHIFT)) < pgoff) 12451da177e4SLinus Torvalds return -EOVERFLOW; 12461da177e4SLinus Torvalds 12471da177e4SLinus Torvalds /* Too many mappings? */ 12481da177e4SLinus Torvalds if (mm->map_count > sysctl_max_map_count) 12491da177e4SLinus Torvalds return -ENOMEM; 12501da177e4SLinus Torvalds 12511da177e4SLinus Torvalds /* Obtain the address to map to. we verify (or select) it and ensure 12521da177e4SLinus Torvalds * that it represents a valid section of the address space. 12531da177e4SLinus Torvalds */ 12541da177e4SLinus Torvalds addr = get_unmapped_area(file, addr, len, pgoff, flags); 1255ff68dac6SGaowei Pu if (IS_ERR_VALUE(addr)) 12561da177e4SLinus Torvalds return addr; 12571da177e4SLinus Torvalds 1258a4ff8e86SMichal Hocko if (flags & MAP_FIXED_NOREPLACE) { 125935e43c5fSLiam Howlett if (find_vma_intersection(mm, addr, addr + len)) 1260a4ff8e86SMichal Hocko return -EEXIST; 1261a4ff8e86SMichal Hocko } 1262a4ff8e86SMichal Hocko 126362b5f7d0SDave Hansen if (prot == PROT_EXEC) { 126462b5f7d0SDave Hansen pkey = execute_only_pkey(mm); 126562b5f7d0SDave Hansen if (pkey < 0) 126662b5f7d0SDave Hansen pkey = 0; 126762b5f7d0SDave Hansen } 126862b5f7d0SDave Hansen 12691da177e4SLinus Torvalds /* Do simple checking here so the lower-level routines won't have 12701da177e4SLinus Torvalds * to. we assume access permissions have been handled by the open 12711da177e4SLinus Torvalds * of the memory object, so we don't do any here. 12721da177e4SLinus Torvalds */ 127345e55300SPeter Collingbourne vm_flags = calc_vm_prot_bits(prot, pkey) | calc_vm_flag_bits(flags) | 12741da177e4SLinus Torvalds mm->def_flags | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC; 12751da177e4SLinus Torvalds 1276cdf7b341SHuang Shijie if (flags & MAP_LOCKED) 12771da177e4SLinus Torvalds if (!can_do_mlock()) 12781da177e4SLinus Torvalds return -EPERM; 1279ba470de4SRik van Riel 1280363ee17fSDavidlohr Bueso if (mlock_future_check(mm, vm_flags, len)) 12811da177e4SLinus Torvalds return -EAGAIN; 12821da177e4SLinus Torvalds 12831da177e4SLinus Torvalds if (file) { 1284077bf22bSOleg Nesterov struct inode *inode = file_inode(file); 12851c972597SDan Williams unsigned long flags_mask; 12861c972597SDan Williams 1287be83bbf8SLinus Torvalds if (!file_mmap_ok(file, inode, pgoff, len)) 1288be83bbf8SLinus Torvalds return -EOVERFLOW; 1289be83bbf8SLinus Torvalds 12901c972597SDan Williams flags_mask = LEGACY_MAP_MASK | file->f_op->mmap_supported_flags; 1291077bf22bSOleg Nesterov 12921da177e4SLinus Torvalds switch (flags & MAP_TYPE) { 12931da177e4SLinus Torvalds case MAP_SHARED: 12941c972597SDan Williams /* 12951c972597SDan Williams * Force use of MAP_SHARED_VALIDATE with non-legacy 12961c972597SDan Williams * flags. E.g. MAP_SYNC is dangerous to use with 12971c972597SDan Williams * MAP_SHARED as you don't know which consistency model 12981c972597SDan Williams * you will get. We silently ignore unsupported flags 12991c972597SDan Williams * with MAP_SHARED to preserve backward compatibility. 13001c972597SDan Williams */ 13011c972597SDan Williams flags &= LEGACY_MAP_MASK; 1302e4a9bc58SJoe Perches fallthrough; 13031c972597SDan Williams case MAP_SHARED_VALIDATE: 13041c972597SDan Williams if (flags & ~flags_mask) 13051c972597SDan Williams return -EOPNOTSUPP; 1306dc617f29SDarrick J. Wong if (prot & PROT_WRITE) { 1307dc617f29SDarrick J. Wong if (!(file->f_mode & FMODE_WRITE)) 13081da177e4SLinus Torvalds return -EACCES; 1309dc617f29SDarrick J. Wong if (IS_SWAPFILE(file->f_mapping->host)) 1310dc617f29SDarrick J. Wong return -ETXTBSY; 1311dc617f29SDarrick J. Wong } 13121da177e4SLinus Torvalds 13131da177e4SLinus Torvalds /* 13141da177e4SLinus Torvalds * Make sure we don't allow writing to an append-only 13151da177e4SLinus Torvalds * file.. 13161da177e4SLinus Torvalds */ 13171da177e4SLinus Torvalds if (IS_APPEND(inode) && (file->f_mode & FMODE_WRITE)) 13181da177e4SLinus Torvalds return -EACCES; 13191da177e4SLinus Torvalds 13201da177e4SLinus Torvalds vm_flags |= VM_SHARED | VM_MAYSHARE; 13211da177e4SLinus Torvalds if (!(file->f_mode & FMODE_WRITE)) 13221da177e4SLinus Torvalds vm_flags &= ~(VM_MAYWRITE | VM_SHARED); 1323e4a9bc58SJoe Perches fallthrough; 13241da177e4SLinus Torvalds case MAP_PRIVATE: 13251da177e4SLinus Torvalds if (!(file->f_mode & FMODE_READ)) 13261da177e4SLinus Torvalds return -EACCES; 132790f8572bSEric W. Biederman if (path_noexec(&file->f_path)) { 132880c5606cSLinus Torvalds if (vm_flags & VM_EXEC) 132980c5606cSLinus Torvalds return -EPERM; 133080c5606cSLinus Torvalds vm_flags &= ~VM_MAYEXEC; 133180c5606cSLinus Torvalds } 133280c5606cSLinus Torvalds 133372c2d531SAl Viro if (!file->f_op->mmap) 133480c5606cSLinus Torvalds return -ENODEV; 1335b2c56e4fSOleg Nesterov if (vm_flags & (VM_GROWSDOWN|VM_GROWSUP)) 1336b2c56e4fSOleg Nesterov return -EINVAL; 13371da177e4SLinus Torvalds break; 13381da177e4SLinus Torvalds 13391da177e4SLinus Torvalds default: 13401da177e4SLinus Torvalds return -EINVAL; 13411da177e4SLinus Torvalds } 13421da177e4SLinus Torvalds } else { 13431da177e4SLinus Torvalds switch (flags & MAP_TYPE) { 13441da177e4SLinus Torvalds case MAP_SHARED: 1345b2c56e4fSOleg Nesterov if (vm_flags & (VM_GROWSDOWN|VM_GROWSUP)) 1346b2c56e4fSOleg Nesterov return -EINVAL; 1347ce363942STejun Heo /* 1348ce363942STejun Heo * Ignore pgoff. 1349ce363942STejun Heo */ 1350ce363942STejun Heo pgoff = 0; 13511da177e4SLinus Torvalds vm_flags |= VM_SHARED | VM_MAYSHARE; 13521da177e4SLinus Torvalds break; 13531da177e4SLinus Torvalds case MAP_PRIVATE: 13541da177e4SLinus Torvalds /* 13551da177e4SLinus Torvalds * Set pgoff according to addr for anon_vma. 13561da177e4SLinus Torvalds */ 13571da177e4SLinus Torvalds pgoff = addr >> PAGE_SHIFT; 13581da177e4SLinus Torvalds break; 13591da177e4SLinus Torvalds default: 13601da177e4SLinus Torvalds return -EINVAL; 13611da177e4SLinus Torvalds } 13621da177e4SLinus Torvalds } 13631da177e4SLinus Torvalds 1364c22c0d63SMichel Lespinasse /* 1365c22c0d63SMichel Lespinasse * Set 'VM_NORESERVE' if we should not account for the 1366c22c0d63SMichel Lespinasse * memory use of this mapping. 1367c22c0d63SMichel Lespinasse */ 1368c22c0d63SMichel Lespinasse if (flags & MAP_NORESERVE) { 1369c22c0d63SMichel Lespinasse /* We honor MAP_NORESERVE if allowed to overcommit */ 1370c22c0d63SMichel Lespinasse if (sysctl_overcommit_memory != OVERCOMMIT_NEVER) 1371c22c0d63SMichel Lespinasse vm_flags |= VM_NORESERVE; 1372c22c0d63SMichel Lespinasse 1373c22c0d63SMichel Lespinasse /* hugetlb applies strict overcommit unless MAP_NORESERVE */ 1374c22c0d63SMichel Lespinasse if (file && is_file_hugepages(file)) 1375c22c0d63SMichel Lespinasse vm_flags |= VM_NORESERVE; 1376c22c0d63SMichel Lespinasse } 1377c22c0d63SMichel Lespinasse 1378897ab3e0SMike Rapoport addr = mmap_region(file, addr, len, vm_flags, pgoff, uf); 137909a9f1d2SMichel Lespinasse if (!IS_ERR_VALUE(addr) && 138009a9f1d2SMichel Lespinasse ((vm_flags & VM_LOCKED) || 138109a9f1d2SMichel Lespinasse (flags & (MAP_POPULATE | MAP_NONBLOCK)) == MAP_POPULATE)) 138241badc15SMichel Lespinasse *populate = len; 1383bebeb3d6SMichel Lespinasse return addr; 13840165ab44SMiklos Szeredi } 13856be5ceb0SLinus Torvalds 1386a90f590aSDominik Brodowski unsigned long ksys_mmap_pgoff(unsigned long addr, unsigned long len, 1387a90f590aSDominik Brodowski unsigned long prot, unsigned long flags, 1388a90f590aSDominik Brodowski unsigned long fd, unsigned long pgoff) 138966f0dc48SHugh Dickins { 139066f0dc48SHugh Dickins struct file *file = NULL; 13911e3ee14bSChen Gang unsigned long retval; 139266f0dc48SHugh Dickins 139366f0dc48SHugh Dickins if (!(flags & MAP_ANONYMOUS)) { 1394120a795dSAl Viro audit_mmap_fd(fd, flags); 139566f0dc48SHugh Dickins file = fget(fd); 139666f0dc48SHugh Dickins if (!file) 13971e3ee14bSChen Gang return -EBADF; 13987bba8f0eSZhen Lei if (is_file_hugepages(file)) { 1399af73e4d9SNaoya Horiguchi len = ALIGN(len, huge_page_size(hstate_file(file))); 14007bba8f0eSZhen Lei } else if (unlikely(flags & MAP_HUGETLB)) { 1401493af578SJörn Engel retval = -EINVAL; 1402493af578SJörn Engel goto out_fput; 14037bba8f0eSZhen Lei } 140466f0dc48SHugh Dickins } else if (flags & MAP_HUGETLB) { 1405c103a4dcSAndrew Morton struct hstate *hs; 1406af73e4d9SNaoya Horiguchi 140720ac2893SAnshuman Khandual hs = hstate_sizelog((flags >> MAP_HUGE_SHIFT) & MAP_HUGE_MASK); 1408091d0d55SLi Zefan if (!hs) 1409091d0d55SLi Zefan return -EINVAL; 1410091d0d55SLi Zefan 1411091d0d55SLi Zefan len = ALIGN(len, huge_page_size(hs)); 141266f0dc48SHugh Dickins /* 141366f0dc48SHugh Dickins * VM_NORESERVE is used because the reservations will be 141466f0dc48SHugh Dickins * taken when vm_ops->mmap() is called 141566f0dc48SHugh Dickins */ 1416af73e4d9SNaoya Horiguchi file = hugetlb_file_setup(HUGETLB_ANON_FILE, len, 141742d7395fSAndi Kleen VM_NORESERVE, 141883c1fd76Szhangyiru HUGETLB_ANONHUGE_INODE, 141942d7395fSAndi Kleen (flags >> MAP_HUGE_SHIFT) & MAP_HUGE_MASK); 142066f0dc48SHugh Dickins if (IS_ERR(file)) 142166f0dc48SHugh Dickins return PTR_ERR(file); 142266f0dc48SHugh Dickins } 142366f0dc48SHugh Dickins 14249fbeb5abSMichal Hocko retval = vm_mmap_pgoff(file, addr, len, prot, flags, pgoff); 1425493af578SJörn Engel out_fput: 142666f0dc48SHugh Dickins if (file) 142766f0dc48SHugh Dickins fput(file); 142866f0dc48SHugh Dickins return retval; 142966f0dc48SHugh Dickins } 143066f0dc48SHugh Dickins 1431a90f590aSDominik Brodowski SYSCALL_DEFINE6(mmap_pgoff, unsigned long, addr, unsigned long, len, 1432a90f590aSDominik Brodowski unsigned long, prot, unsigned long, flags, 1433a90f590aSDominik Brodowski unsigned long, fd, unsigned long, pgoff) 1434a90f590aSDominik Brodowski { 1435a90f590aSDominik Brodowski return ksys_mmap_pgoff(addr, len, prot, flags, fd, pgoff); 1436a90f590aSDominik Brodowski } 1437a90f590aSDominik Brodowski 1438a4679373SChristoph Hellwig #ifdef __ARCH_WANT_SYS_OLD_MMAP 1439a4679373SChristoph Hellwig struct mmap_arg_struct { 1440a4679373SChristoph Hellwig unsigned long addr; 1441a4679373SChristoph Hellwig unsigned long len; 1442a4679373SChristoph Hellwig unsigned long prot; 1443a4679373SChristoph Hellwig unsigned long flags; 1444a4679373SChristoph Hellwig unsigned long fd; 1445a4679373SChristoph Hellwig unsigned long offset; 1446a4679373SChristoph Hellwig }; 1447a4679373SChristoph Hellwig 1448a4679373SChristoph Hellwig SYSCALL_DEFINE1(old_mmap, struct mmap_arg_struct __user *, arg) 1449a4679373SChristoph Hellwig { 1450a4679373SChristoph Hellwig struct mmap_arg_struct a; 1451a4679373SChristoph Hellwig 1452a4679373SChristoph Hellwig if (copy_from_user(&a, arg, sizeof(a))) 1453a4679373SChristoph Hellwig return -EFAULT; 1454de1741a1SAlexander Kuleshov if (offset_in_page(a.offset)) 1455a4679373SChristoph Hellwig return -EINVAL; 1456a4679373SChristoph Hellwig 1457a90f590aSDominik Brodowski return ksys_mmap_pgoff(a.addr, a.len, a.prot, a.flags, a.fd, 1458a4679373SChristoph Hellwig a.offset >> PAGE_SHIFT); 1459a4679373SChristoph Hellwig } 1460a4679373SChristoph Hellwig #endif /* __ARCH_WANT_SYS_OLD_MMAP */ 1461a4679373SChristoph Hellwig 14624e950f6fSAlexey Dobriyan /* 14638bb4e7a2SWei Yang * Some shared mappings will want the pages marked read-only 14644e950f6fSAlexey Dobriyan * to track write events. If so, we'll downgrade vm_page_prot 14654e950f6fSAlexey Dobriyan * to the private version (using protection_map[] without the 14664e950f6fSAlexey Dobriyan * VM_SHARED bit). 14674e950f6fSAlexey Dobriyan */ 14686d2329f8SAndrea Arcangeli int vma_wants_writenotify(struct vm_area_struct *vma, pgprot_t vm_page_prot) 14694e950f6fSAlexey Dobriyan { 1470ca16d140SKOSAKI Motohiro vm_flags_t vm_flags = vma->vm_flags; 14718a04446aSKirill A. Shutemov const struct vm_operations_struct *vm_ops = vma->vm_ops; 14724e950f6fSAlexey Dobriyan 14734e950f6fSAlexey Dobriyan /* If it was private or non-writable, the write bit is already clear */ 14744e950f6fSAlexey Dobriyan if ((vm_flags & (VM_WRITE|VM_SHARED)) != ((VM_WRITE|VM_SHARED))) 14754e950f6fSAlexey Dobriyan return 0; 14764e950f6fSAlexey Dobriyan 14774e950f6fSAlexey Dobriyan /* The backer wishes to know when pages are first written to? */ 14788a04446aSKirill A. Shutemov if (vm_ops && (vm_ops->page_mkwrite || vm_ops->pfn_mkwrite)) 14794e950f6fSAlexey Dobriyan return 1; 14804e950f6fSAlexey Dobriyan 148164e45507SPeter Feiner /* The open routine did something to the protections that pgprot_modify 148264e45507SPeter Feiner * won't preserve? */ 14836d2329f8SAndrea Arcangeli if (pgprot_val(vm_page_prot) != 14846d2329f8SAndrea Arcangeli pgprot_val(vm_pgprot_modify(vm_page_prot, vm_flags))) 14854e950f6fSAlexey Dobriyan return 0; 14864e950f6fSAlexey Dobriyan 1487f96f7a40SDavid Hildenbrand /* 1488f96f7a40SDavid Hildenbrand * Do we need to track softdirty? hugetlb does not support softdirty 1489f96f7a40SDavid Hildenbrand * tracking yet. 1490f96f7a40SDavid Hildenbrand */ 1491f96f7a40SDavid Hildenbrand if (vma_soft_dirty_enabled(vma) && !is_vm_hugetlb_page(vma)) 149264e45507SPeter Feiner return 1; 149364e45507SPeter Feiner 149451d3d5ebSDavid Hildenbrand /* Do we need write faults for uffd-wp tracking? */ 149551d3d5ebSDavid Hildenbrand if (userfaultfd_wp(vma)) 149651d3d5ebSDavid Hildenbrand return 1; 149751d3d5ebSDavid Hildenbrand 14984e950f6fSAlexey Dobriyan /* Specialty mapping? */ 14994b6e1e37SKonstantin Khlebnikov if (vm_flags & VM_PFNMAP) 15004e950f6fSAlexey Dobriyan return 0; 15014e950f6fSAlexey Dobriyan 15024e950f6fSAlexey Dobriyan /* Can the mapping track the dirty pages? */ 15034e950f6fSAlexey Dobriyan return vma->vm_file && vma->vm_file->f_mapping && 1504f56753acSChristoph Hellwig mapping_can_writeback(vma->vm_file->f_mapping); 15054e950f6fSAlexey Dobriyan } 15064e950f6fSAlexey Dobriyan 1507fc8744adSLinus Torvalds /* 1508fc8744adSLinus Torvalds * We account for memory if it's a private writeable mapping, 15095a6fe125SMel Gorman * not hugepages and VM_NORESERVE wasn't set. 1510fc8744adSLinus Torvalds */ 1511ca16d140SKOSAKI Motohiro static inline int accountable_mapping(struct file *file, vm_flags_t vm_flags) 1512fc8744adSLinus Torvalds { 15135a6fe125SMel Gorman /* 15145a6fe125SMel Gorman * hugetlb has its own accounting separate from the core VM 15155a6fe125SMel Gorman * VM_HUGETLB may not be set yet so we cannot check for that flag. 15165a6fe125SMel Gorman */ 15175a6fe125SMel Gorman if (file && is_file_hugepages(file)) 15185a6fe125SMel Gorman return 0; 15195a6fe125SMel Gorman 1520fc8744adSLinus Torvalds return (vm_flags & (VM_NORESERVE | VM_SHARED | VM_WRITE)) == VM_WRITE; 1521fc8744adSLinus Torvalds } 1522fc8744adSLinus Torvalds 15233499a131SLiam R. Howlett /** 15243499a131SLiam R. Howlett * unmapped_area() - Find an area between the low_limit and the high_limit with 15253499a131SLiam R. Howlett * the correct alignment and offset, all from @info. Note: current->mm is used 15263499a131SLiam R. Howlett * for the search. 15273499a131SLiam R. Howlett * 152882b24936SVernon Yang * @info: The unmapped area information including the range [low_limit - 152982b24936SVernon Yang * high_limit), the alignment offset and mask. 15303499a131SLiam R. Howlett * 15313499a131SLiam R. Howlett * Return: A memory address or -ENOMEM. 15323499a131SLiam R. Howlett */ 1533baceaf1cSJaewon Kim static unsigned long unmapped_area(struct vm_unmapped_area_info *info) 1534db4fbfb9SMichel Lespinasse { 15353499a131SLiam R. Howlett unsigned long length, gap; 1536db4fbfb9SMichel Lespinasse 15373499a131SLiam R. Howlett MA_STATE(mas, ¤t->mm->mm_mt, 0, 0); 1538db4fbfb9SMichel Lespinasse 1539db4fbfb9SMichel Lespinasse /* Adjust search length to account for worst case alignment overhead */ 1540db4fbfb9SMichel Lespinasse length = info->length + info->align_mask; 1541db4fbfb9SMichel Lespinasse if (length < info->length) 1542db4fbfb9SMichel Lespinasse return -ENOMEM; 1543db4fbfb9SMichel Lespinasse 15443499a131SLiam R. Howlett if (mas_empty_area(&mas, info->low_limit, info->high_limit - 1, 15453499a131SLiam R. Howlett length)) 15463499a131SLiam R. Howlett return -ENOMEM; 15473499a131SLiam R. Howlett 1548d4af56c5SLiam R. Howlett gap = mas.index; 1549d4af56c5SLiam R. Howlett gap += (info->align_offset - gap) & info->align_mask; 15503499a131SLiam R. Howlett return gap; 1551db4fbfb9SMichel Lespinasse } 1552db4fbfb9SMichel Lespinasse 15533499a131SLiam R. Howlett /** 15543499a131SLiam R. Howlett * unmapped_area_topdown() - Find an area between the low_limit and the 155582b24936SVernon Yang * high_limit with the correct alignment and offset at the highest available 15563499a131SLiam R. Howlett * address, all from @info. Note: current->mm is used for the search. 15573499a131SLiam R. Howlett * 155882b24936SVernon Yang * @info: The unmapped area information including the range [low_limit - 155982b24936SVernon Yang * high_limit), the alignment offset and mask. 15603499a131SLiam R. Howlett * 15613499a131SLiam R. Howlett * Return: A memory address or -ENOMEM. 15623499a131SLiam R. Howlett */ 1563baceaf1cSJaewon Kim static unsigned long unmapped_area_topdown(struct vm_unmapped_area_info *info) 1564db4fbfb9SMichel Lespinasse { 15653499a131SLiam R. Howlett unsigned long length, gap; 1566d4af56c5SLiam R. Howlett 15673499a131SLiam R. Howlett MA_STATE(mas, ¤t->mm->mm_mt, 0, 0); 1568db4fbfb9SMichel Lespinasse /* Adjust search length to account for worst case alignment overhead */ 1569db4fbfb9SMichel Lespinasse length = info->length + info->align_mask; 1570db4fbfb9SMichel Lespinasse if (length < info->length) 1571db4fbfb9SMichel Lespinasse return -ENOMEM; 1572db4fbfb9SMichel Lespinasse 15733499a131SLiam R. Howlett if (mas_empty_area_rev(&mas, info->low_limit, info->high_limit - 1, 15743499a131SLiam R. Howlett length)) 15753499a131SLiam R. Howlett return -ENOMEM; 15763499a131SLiam R. Howlett 1577d4af56c5SLiam R. Howlett gap = mas.last + 1 - info->length; 1578d4af56c5SLiam R. Howlett gap -= (gap - info->align_offset) & info->align_mask; 15793499a131SLiam R. Howlett return gap; 1580db4fbfb9SMichel Lespinasse } 1581db4fbfb9SMichel Lespinasse 1582baceaf1cSJaewon Kim /* 1583baceaf1cSJaewon Kim * Search for an unmapped address range. 1584baceaf1cSJaewon Kim * 1585baceaf1cSJaewon Kim * We are looking for a range that: 1586baceaf1cSJaewon Kim * - does not intersect with any VMA; 1587baceaf1cSJaewon Kim * - is contained within the [low_limit, high_limit) interval; 1588baceaf1cSJaewon Kim * - is at least the desired size. 1589baceaf1cSJaewon Kim * - satisfies (begin_addr & align_mask) == (align_offset & align_mask) 1590baceaf1cSJaewon Kim */ 1591baceaf1cSJaewon Kim unsigned long vm_unmapped_area(struct vm_unmapped_area_info *info) 1592baceaf1cSJaewon Kim { 1593df529cabSJaewon Kim unsigned long addr; 1594df529cabSJaewon Kim 1595baceaf1cSJaewon Kim if (info->flags & VM_UNMAPPED_AREA_TOPDOWN) 1596df529cabSJaewon Kim addr = unmapped_area_topdown(info); 1597baceaf1cSJaewon Kim else 1598df529cabSJaewon Kim addr = unmapped_area(info); 1599df529cabSJaewon Kim 1600df529cabSJaewon Kim trace_vm_unmapped_area(addr, info); 1601df529cabSJaewon Kim return addr; 1602baceaf1cSJaewon Kim } 1603f6795053SSteve Capper 16041da177e4SLinus Torvalds /* Get an address range which is currently unmapped. 16051da177e4SLinus Torvalds * For shmat() with addr=0. 16061da177e4SLinus Torvalds * 16071da177e4SLinus Torvalds * Ugly calling convention alert: 16081da177e4SLinus Torvalds * Return value with the low bits set means error value, 16091da177e4SLinus Torvalds * ie 16101da177e4SLinus Torvalds * if (ret & ~PAGE_MASK) 16111da177e4SLinus Torvalds * error = ret; 16121da177e4SLinus Torvalds * 16131da177e4SLinus Torvalds * This function "knows" that -ENOMEM has the bits set. 16141da177e4SLinus Torvalds */ 16151da177e4SLinus Torvalds unsigned long 16164b439e25SChristophe Leroy generic_get_unmapped_area(struct file *filp, unsigned long addr, 16174b439e25SChristophe Leroy unsigned long len, unsigned long pgoff, 16184b439e25SChristophe Leroy unsigned long flags) 16191da177e4SLinus Torvalds { 16201da177e4SLinus Torvalds struct mm_struct *mm = current->mm; 16211be7107fSHugh Dickins struct vm_area_struct *vma, *prev; 1622db4fbfb9SMichel Lespinasse struct vm_unmapped_area_info info; 16232cb4de08SChristophe Leroy const unsigned long mmap_end = arch_get_mmap_end(addr, len, flags); 16241da177e4SLinus Torvalds 1625f6795053SSteve Capper if (len > mmap_end - mmap_min_addr) 16261da177e4SLinus Torvalds return -ENOMEM; 16271da177e4SLinus Torvalds 162806abdfb4SBenjamin Herrenschmidt if (flags & MAP_FIXED) 162906abdfb4SBenjamin Herrenschmidt return addr; 163006abdfb4SBenjamin Herrenschmidt 16311da177e4SLinus Torvalds if (addr) { 16321da177e4SLinus Torvalds addr = PAGE_ALIGN(addr); 16331be7107fSHugh Dickins vma = find_vma_prev(mm, addr, &prev); 1634f6795053SSteve Capper if (mmap_end - len >= addr && addr >= mmap_min_addr && 16351be7107fSHugh Dickins (!vma || addr + len <= vm_start_gap(vma)) && 16361be7107fSHugh Dickins (!prev || addr >= vm_end_gap(prev))) 16371da177e4SLinus Torvalds return addr; 16381da177e4SLinus Torvalds } 16391da177e4SLinus Torvalds 1640db4fbfb9SMichel Lespinasse info.flags = 0; 1641db4fbfb9SMichel Lespinasse info.length = len; 16424e99b021SHeiko Carstens info.low_limit = mm->mmap_base; 1643f6795053SSteve Capper info.high_limit = mmap_end; 1644db4fbfb9SMichel Lespinasse info.align_mask = 0; 164509ef5283SJaewon Kim info.align_offset = 0; 1646db4fbfb9SMichel Lespinasse return vm_unmapped_area(&info); 16471da177e4SLinus Torvalds } 16484b439e25SChristophe Leroy 16494b439e25SChristophe Leroy #ifndef HAVE_ARCH_UNMAPPED_AREA 16504b439e25SChristophe Leroy unsigned long 16514b439e25SChristophe Leroy arch_get_unmapped_area(struct file *filp, unsigned long addr, 16524b439e25SChristophe Leroy unsigned long len, unsigned long pgoff, 16534b439e25SChristophe Leroy unsigned long flags) 16544b439e25SChristophe Leroy { 16554b439e25SChristophe Leroy return generic_get_unmapped_area(filp, addr, len, pgoff, flags); 16564b439e25SChristophe Leroy } 16571da177e4SLinus Torvalds #endif 16581da177e4SLinus Torvalds 16591da177e4SLinus Torvalds /* 16601da177e4SLinus Torvalds * This mmap-allocator allocates new areas top-down from below the 16611da177e4SLinus Torvalds * stack's low limit (the base): 16621da177e4SLinus Torvalds */ 16631da177e4SLinus Torvalds unsigned long 16644b439e25SChristophe Leroy generic_get_unmapped_area_topdown(struct file *filp, unsigned long addr, 166543cca0b1SYang Fan unsigned long len, unsigned long pgoff, 166643cca0b1SYang Fan unsigned long flags) 16671da177e4SLinus Torvalds { 16681be7107fSHugh Dickins struct vm_area_struct *vma, *prev; 16691da177e4SLinus Torvalds struct mm_struct *mm = current->mm; 1670db4fbfb9SMichel Lespinasse struct vm_unmapped_area_info info; 16712cb4de08SChristophe Leroy const unsigned long mmap_end = arch_get_mmap_end(addr, len, flags); 16721da177e4SLinus Torvalds 16731da177e4SLinus Torvalds /* requested length too big for entire address space */ 1674f6795053SSteve Capper if (len > mmap_end - mmap_min_addr) 16751da177e4SLinus Torvalds return -ENOMEM; 16761da177e4SLinus Torvalds 167706abdfb4SBenjamin Herrenschmidt if (flags & MAP_FIXED) 167806abdfb4SBenjamin Herrenschmidt return addr; 167906abdfb4SBenjamin Herrenschmidt 16801da177e4SLinus Torvalds /* requesting a specific address */ 16811da177e4SLinus Torvalds if (addr) { 16821da177e4SLinus Torvalds addr = PAGE_ALIGN(addr); 16831be7107fSHugh Dickins vma = find_vma_prev(mm, addr, &prev); 1684f6795053SSteve Capper if (mmap_end - len >= addr && addr >= mmap_min_addr && 16851be7107fSHugh Dickins (!vma || addr + len <= vm_start_gap(vma)) && 16861be7107fSHugh Dickins (!prev || addr >= vm_end_gap(prev))) 16871da177e4SLinus Torvalds return addr; 16881da177e4SLinus Torvalds } 16891da177e4SLinus Torvalds 1690db4fbfb9SMichel Lespinasse info.flags = VM_UNMAPPED_AREA_TOPDOWN; 1691db4fbfb9SMichel Lespinasse info.length = len; 16922afc745fSAkira Takeuchi info.low_limit = max(PAGE_SIZE, mmap_min_addr); 1693f6795053SSteve Capper info.high_limit = arch_get_mmap_base(addr, mm->mmap_base); 1694db4fbfb9SMichel Lespinasse info.align_mask = 0; 169509ef5283SJaewon Kim info.align_offset = 0; 1696db4fbfb9SMichel Lespinasse addr = vm_unmapped_area(&info); 1697b716ad95SXiao Guangrong 16981da177e4SLinus Torvalds /* 16991da177e4SLinus Torvalds * A failed mmap() very likely causes application failure, 17001da177e4SLinus Torvalds * so fall back to the bottom-up function here. This scenario 17011da177e4SLinus Torvalds * can happen with large stack limits and large mmap() 17021da177e4SLinus Torvalds * allocations. 17031da177e4SLinus Torvalds */ 1704de1741a1SAlexander Kuleshov if (offset_in_page(addr)) { 1705db4fbfb9SMichel Lespinasse VM_BUG_ON(addr != -ENOMEM); 1706db4fbfb9SMichel Lespinasse info.flags = 0; 1707db4fbfb9SMichel Lespinasse info.low_limit = TASK_UNMAPPED_BASE; 1708f6795053SSteve Capper info.high_limit = mmap_end; 1709db4fbfb9SMichel Lespinasse addr = vm_unmapped_area(&info); 1710db4fbfb9SMichel Lespinasse } 17111da177e4SLinus Torvalds 17121da177e4SLinus Torvalds return addr; 17131da177e4SLinus Torvalds } 17144b439e25SChristophe Leroy 17154b439e25SChristophe Leroy #ifndef HAVE_ARCH_UNMAPPED_AREA_TOPDOWN 17164b439e25SChristophe Leroy unsigned long 17174b439e25SChristophe Leroy arch_get_unmapped_area_topdown(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_topdown(filp, addr, len, pgoff, flags); 17224b439e25SChristophe Leroy } 17231da177e4SLinus Torvalds #endif 17241da177e4SLinus Torvalds 17251da177e4SLinus Torvalds unsigned long 17261da177e4SLinus Torvalds get_unmapped_area(struct file *file, unsigned long addr, unsigned long len, 17271da177e4SLinus Torvalds unsigned long pgoff, unsigned long flags) 17281da177e4SLinus Torvalds { 172906abdfb4SBenjamin Herrenschmidt unsigned long (*get_area)(struct file *, unsigned long, 173006abdfb4SBenjamin Herrenschmidt unsigned long, unsigned long, unsigned long); 173107ab67c8SLinus Torvalds 17329206de95SAl Viro unsigned long error = arch_mmap_check(addr, len, flags); 17339206de95SAl Viro if (error) 17349206de95SAl Viro return error; 17359206de95SAl Viro 17369206de95SAl Viro /* Careful about overflows.. */ 17379206de95SAl Viro if (len > TASK_SIZE) 17389206de95SAl Viro return -ENOMEM; 17399206de95SAl Viro 174007ab67c8SLinus Torvalds get_area = current->mm->get_unmapped_area; 1741c01d5b30SHugh Dickins if (file) { 1742c01d5b30SHugh Dickins if (file->f_op->get_unmapped_area) 174307ab67c8SLinus Torvalds get_area = file->f_op->get_unmapped_area; 1744c01d5b30SHugh Dickins } else if (flags & MAP_SHARED) { 1745c01d5b30SHugh Dickins /* 1746c01d5b30SHugh Dickins * mmap_region() will call shmem_zero_setup() to create a file, 1747c01d5b30SHugh Dickins * so use shmem's get_unmapped_area in case it can be huge. 174845e55300SPeter Collingbourne * do_mmap() will clear pgoff, so match alignment. 1749c01d5b30SHugh Dickins */ 1750c01d5b30SHugh Dickins pgoff = 0; 1751c01d5b30SHugh Dickins get_area = shmem_get_unmapped_area; 1752c01d5b30SHugh Dickins } 1753c01d5b30SHugh Dickins 175407ab67c8SLinus Torvalds addr = get_area(file, addr, len, pgoff, flags); 175507ab67c8SLinus Torvalds if (IS_ERR_VALUE(addr)) 175607ab67c8SLinus Torvalds return addr; 175707ab67c8SLinus Torvalds 17581da177e4SLinus Torvalds if (addr > TASK_SIZE - len) 17591da177e4SLinus Torvalds return -ENOMEM; 1760de1741a1SAlexander Kuleshov if (offset_in_page(addr)) 17611da177e4SLinus Torvalds return -EINVAL; 176206abdfb4SBenjamin Herrenschmidt 17639ac4ed4bSAl Viro error = security_mmap_addr(addr); 17649ac4ed4bSAl Viro return error ? error : addr; 17651da177e4SLinus Torvalds } 17661da177e4SLinus Torvalds 17671da177e4SLinus Torvalds EXPORT_SYMBOL(get_unmapped_area); 17681da177e4SLinus Torvalds 1769be8432e7SLiam R. Howlett /** 1770abdba2ddSLiam R. Howlett * find_vma_intersection() - Look up the first VMA which intersects the interval 1771abdba2ddSLiam R. Howlett * @mm: The process address space. 1772abdba2ddSLiam R. Howlett * @start_addr: The inclusive start user address. 1773abdba2ddSLiam R. Howlett * @end_addr: The exclusive end user address. 1774abdba2ddSLiam R. Howlett * 1775abdba2ddSLiam R. Howlett * Returns: The first VMA within the provided range, %NULL otherwise. Assumes 1776abdba2ddSLiam R. Howlett * start_addr < end_addr. 1777abdba2ddSLiam R. Howlett */ 1778abdba2ddSLiam R. Howlett struct vm_area_struct *find_vma_intersection(struct mm_struct *mm, 1779abdba2ddSLiam R. Howlett unsigned long start_addr, 1780abdba2ddSLiam R. Howlett unsigned long end_addr) 1781abdba2ddSLiam R. Howlett { 1782abdba2ddSLiam R. Howlett unsigned long index = start_addr; 1783abdba2ddSLiam R. Howlett 1784abdba2ddSLiam R. Howlett mmap_assert_locked(mm); 17857964cf8cSLiam R. Howlett return mt_find(&mm->mm_mt, &index, end_addr - 1); 1786abdba2ddSLiam R. Howlett } 1787abdba2ddSLiam R. Howlett EXPORT_SYMBOL(find_vma_intersection); 1788abdba2ddSLiam R. Howlett 1789abdba2ddSLiam R. Howlett /** 1790be8432e7SLiam R. Howlett * find_vma() - Find the VMA for a given address, or the next VMA. 1791be8432e7SLiam R. Howlett * @mm: The mm_struct to check 1792be8432e7SLiam R. Howlett * @addr: The address 1793be8432e7SLiam R. Howlett * 1794be8432e7SLiam R. Howlett * Returns: The VMA associated with addr, or the next VMA. 1795be8432e7SLiam R. Howlett * May return %NULL in the case of no VMA at addr or above. 1796be8432e7SLiam R. Howlett */ 17971da177e4SLinus Torvalds struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr) 17981da177e4SLinus Torvalds { 1799be8432e7SLiam R. Howlett unsigned long index = addr; 18001da177e4SLinus Torvalds 18015b78ed24SLuigi Rizzo mmap_assert_locked(mm); 18027964cf8cSLiam R. Howlett return mt_find(&mm->mm_mt, &index, ULONG_MAX); 18031da177e4SLinus Torvalds } 18041da177e4SLinus Torvalds EXPORT_SYMBOL(find_vma); 18051da177e4SLinus Torvalds 18067fdbd37dSLiam R. Howlett /** 18077fdbd37dSLiam R. Howlett * find_vma_prev() - Find the VMA for a given address, or the next vma and 18087fdbd37dSLiam R. Howlett * set %pprev to the previous VMA, if any. 18097fdbd37dSLiam R. Howlett * @mm: The mm_struct to check 18107fdbd37dSLiam R. Howlett * @addr: The address 18117fdbd37dSLiam R. Howlett * @pprev: The pointer to set to the previous VMA 18127fdbd37dSLiam R. Howlett * 18137fdbd37dSLiam R. Howlett * Note that RCU lock is missing here since the external mmap_lock() is used 18147fdbd37dSLiam R. Howlett * instead. 18157fdbd37dSLiam R. Howlett * 18167fdbd37dSLiam R. Howlett * Returns: The VMA associated with @addr, or the next vma. 18177fdbd37dSLiam R. Howlett * May return %NULL in the case of no vma at addr or above. 18186bd4837dSKOSAKI Motohiro */ 18191da177e4SLinus Torvalds struct vm_area_struct * 18201da177e4SLinus Torvalds find_vma_prev(struct mm_struct *mm, unsigned long addr, 18211da177e4SLinus Torvalds struct vm_area_struct **pprev) 18221da177e4SLinus Torvalds { 18236bd4837dSKOSAKI Motohiro struct vm_area_struct *vma; 18247fdbd37dSLiam R. Howlett MA_STATE(mas, &mm->mm_mt, addr, addr); 18251da177e4SLinus Torvalds 18267fdbd37dSLiam R. Howlett vma = mas_walk(&mas); 18277fdbd37dSLiam R. Howlett *pprev = mas_prev(&mas, 0); 18287fdbd37dSLiam R. Howlett if (!vma) 18297fdbd37dSLiam R. Howlett vma = mas_next(&mas, ULONG_MAX); 18306bd4837dSKOSAKI Motohiro return vma; 18311da177e4SLinus Torvalds } 18321da177e4SLinus Torvalds 18331da177e4SLinus Torvalds /* 18341da177e4SLinus Torvalds * Verify that the stack growth is acceptable and 18351da177e4SLinus Torvalds * update accounting. This is shared with both the 18361da177e4SLinus Torvalds * grow-up and grow-down cases. 18371da177e4SLinus Torvalds */ 18381be7107fSHugh Dickins static int acct_stack_growth(struct vm_area_struct *vma, 18391be7107fSHugh Dickins unsigned long size, unsigned long grow) 18401da177e4SLinus Torvalds { 18411da177e4SLinus Torvalds struct mm_struct *mm = vma->vm_mm; 18421be7107fSHugh Dickins unsigned long new_start; 18431da177e4SLinus Torvalds 18441da177e4SLinus Torvalds /* address space limit tests */ 184584638335SKonstantin Khlebnikov if (!may_expand_vm(mm, vma->vm_flags, grow)) 18461da177e4SLinus Torvalds return -ENOMEM; 18471da177e4SLinus Torvalds 18481da177e4SLinus Torvalds /* Stack limit test */ 184924c79d8eSKrzysztof Opasiak if (size > rlimit(RLIMIT_STACK)) 18501da177e4SLinus Torvalds return -ENOMEM; 18511da177e4SLinus Torvalds 18521da177e4SLinus Torvalds /* mlock limit tests */ 1853c5d8a364SMiaohe Lin if (mlock_future_check(mm, vma->vm_flags, grow << PAGE_SHIFT)) 18541da177e4SLinus Torvalds return -ENOMEM; 18551da177e4SLinus Torvalds 18560d59a01bSAdam Litke /* Check to ensure the stack will not grow into a hugetlb-only region */ 18570d59a01bSAdam Litke new_start = (vma->vm_flags & VM_GROWSUP) ? vma->vm_start : 18580d59a01bSAdam Litke vma->vm_end - size; 18590d59a01bSAdam Litke if (is_hugepage_only_range(vma->vm_mm, new_start, size)) 18600d59a01bSAdam Litke return -EFAULT; 18610d59a01bSAdam Litke 18621da177e4SLinus Torvalds /* 18631da177e4SLinus Torvalds * Overcommit.. This must be the final test, as it will 18641da177e4SLinus Torvalds * update security statistics. 18651da177e4SLinus Torvalds */ 186605fa199dSHugh Dickins if (security_vm_enough_memory_mm(mm, grow)) 18671da177e4SLinus Torvalds return -ENOMEM; 18681da177e4SLinus Torvalds 18691da177e4SLinus Torvalds return 0; 18701da177e4SLinus Torvalds } 18711da177e4SLinus Torvalds 187246dea3d0SHugh Dickins #if defined(CONFIG_STACK_GROWSUP) || defined(CONFIG_IA64) 18731da177e4SLinus Torvalds /* 187446dea3d0SHugh Dickins * PA-RISC uses this for its stack; IA64 for its Register Backing Store. 187546dea3d0SHugh Dickins * vma is the last one with address > vma->vm_end. Have to extend vma. 18761da177e4SLinus Torvalds */ 187746dea3d0SHugh Dickins int expand_upwards(struct vm_area_struct *vma, unsigned long address) 18781da177e4SLinus Torvalds { 187909357814SOleg Nesterov struct mm_struct *mm = vma->vm_mm; 18801be7107fSHugh Dickins struct vm_area_struct *next; 18811be7107fSHugh Dickins unsigned long gap_addr; 188212352d3cSKonstantin Khlebnikov int error = 0; 1883d4af56c5SLiam R. Howlett MA_STATE(mas, &mm->mm_mt, 0, 0); 18841da177e4SLinus Torvalds 18851da177e4SLinus Torvalds if (!(vma->vm_flags & VM_GROWSUP)) 18861da177e4SLinus Torvalds return -EFAULT; 18871da177e4SLinus Torvalds 1888bd726c90SHelge Deller /* Guard against exceeding limits of the address space. */ 18891be7107fSHugh Dickins address &= PAGE_MASK; 189037511fb5SHelge Deller if (address >= (TASK_SIZE & PAGE_MASK)) 189112352d3cSKonstantin Khlebnikov return -ENOMEM; 1892bd726c90SHelge Deller address += PAGE_SIZE; 189312352d3cSKonstantin Khlebnikov 18941be7107fSHugh Dickins /* Enforce stack_guard_gap */ 18951be7107fSHugh Dickins gap_addr = address + stack_guard_gap; 1896bd726c90SHelge Deller 1897bd726c90SHelge Deller /* Guard against overflow */ 1898bd726c90SHelge Deller if (gap_addr < address || gap_addr > TASK_SIZE) 1899bd726c90SHelge Deller gap_addr = TASK_SIZE; 1900bd726c90SHelge Deller 1901763ecb03SLiam R. Howlett next = find_vma_intersection(mm, vma->vm_end, gap_addr); 1902763ecb03SLiam R. Howlett if (next && vma_is_accessible(next)) { 19031be7107fSHugh Dickins if (!(next->vm_flags & VM_GROWSUP)) 19041be7107fSHugh Dickins return -ENOMEM; 19051be7107fSHugh Dickins /* Check that both stack segments have the same anon_vma? */ 19061be7107fSHugh Dickins } 19071be7107fSHugh Dickins 1908c5d5546eSVernon Yang if (mas_preallocate(&mas, GFP_KERNEL)) 19091da177e4SLinus Torvalds return -ENOMEM; 19101da177e4SLinus Torvalds 1911d4af56c5SLiam R. Howlett /* We must make sure the anon_vma is allocated. */ 1912d4af56c5SLiam R. Howlett if (unlikely(anon_vma_prepare(vma))) { 1913d4af56c5SLiam R. Howlett mas_destroy(&mas); 1914d4af56c5SLiam R. Howlett return -ENOMEM; 1915d4af56c5SLiam R. Howlett } 1916d4af56c5SLiam R. Howlett 19171da177e4SLinus Torvalds /* 19181da177e4SLinus Torvalds * vma->vm_start/vm_end cannot change under us because the caller 1919c1e8d7c6SMichel Lespinasse * is required to hold the mmap_lock in read mode. We need the 19201da177e4SLinus Torvalds * anon_vma lock to serialize against concurrent expand_stacks. 19211da177e4SLinus Torvalds */ 192212352d3cSKonstantin Khlebnikov anon_vma_lock_write(vma->anon_vma); 19231da177e4SLinus Torvalds 19241da177e4SLinus Torvalds /* Somebody else might have raced and expanded it already */ 19251da177e4SLinus Torvalds if (address > vma->vm_end) { 19261da177e4SLinus Torvalds unsigned long size, grow; 19271da177e4SLinus Torvalds 19281da177e4SLinus Torvalds size = address - vma->vm_start; 19291da177e4SLinus Torvalds grow = (address - vma->vm_end) >> PAGE_SHIFT; 19301da177e4SLinus Torvalds 193142c36f63SHugh Dickins error = -ENOMEM; 193242c36f63SHugh Dickins if (vma->vm_pgoff + (size >> PAGE_SHIFT) >= vma->vm_pgoff) { 19331da177e4SLinus Torvalds error = acct_stack_growth(vma, size, grow); 19343af9e859SEric B Munson if (!error) { 19354128997bSMichel Lespinasse /* 1936524e00b3SLiam R. Howlett * We only hold a shared mmap_lock lock here, so 1937524e00b3SLiam R. Howlett * we need to protect against concurrent vma 1938524e00b3SLiam R. Howlett * expansions. anon_vma_lock_write() doesn't 1939524e00b3SLiam R. Howlett * help here, as we don't guarantee that all 1940524e00b3SLiam R. Howlett * growable vmas in a mm share the same root 1941524e00b3SLiam R. Howlett * anon vma. So, we reuse mm->page_table_lock 1942524e00b3SLiam R. Howlett * to guard against concurrent vma expansions. 19434128997bSMichel Lespinasse */ 194409357814SOleg Nesterov spin_lock(&mm->page_table_lock); 194587e8827bSOleg Nesterov if (vma->vm_flags & VM_LOCKED) 194609357814SOleg Nesterov mm->locked_vm += grow; 194784638335SKonstantin Khlebnikov vm_stat_account(mm, vma->vm_flags, grow); 1948bf181b9fSMichel Lespinasse anon_vma_interval_tree_pre_update_vma(vma); 19491da177e4SLinus Torvalds vma->vm_end = address; 1950d4af56c5SLiam R. Howlett /* Overwrite old entry in mtree. */ 1951*fbcc3104SLiam R. Howlett mas_set_range(&mas, vma->vm_start, address - 1); 1952*fbcc3104SLiam R. Howlett mas_store_prealloc(&mas, vma); 1953bf181b9fSMichel Lespinasse anon_vma_interval_tree_post_update_vma(vma); 195409357814SOleg Nesterov spin_unlock(&mm->page_table_lock); 19554128997bSMichel Lespinasse 19563af9e859SEric B Munson perf_event_mmap(vma); 19573af9e859SEric B Munson } 19581da177e4SLinus Torvalds } 195942c36f63SHugh Dickins } 196012352d3cSKonstantin Khlebnikov anon_vma_unlock_write(vma->anon_vma); 1961c791576cSYang Shi khugepaged_enter_vma(vma, vma->vm_flags); 1962d4af56c5SLiam R. Howlett mas_destroy(&mas); 19631da177e4SLinus Torvalds return error; 19641da177e4SLinus Torvalds } 196546dea3d0SHugh Dickins #endif /* CONFIG_STACK_GROWSUP || CONFIG_IA64 */ 196646dea3d0SHugh Dickins 19671da177e4SLinus Torvalds /* 19681da177e4SLinus Torvalds * vma is the first one with address < vma->vm_start. Have to extend vma. 19691da177e4SLinus Torvalds */ 1970524e00b3SLiam R. Howlett int expand_downwards(struct vm_area_struct *vma, unsigned long address) 19711da177e4SLinus Torvalds { 197209357814SOleg Nesterov struct mm_struct *mm = vma->vm_mm; 1973763ecb03SLiam R. Howlett MA_STATE(mas, &mm->mm_mt, vma->vm_start, vma->vm_start); 19741be7107fSHugh Dickins struct vm_area_struct *prev; 19750a1d5299SJann Horn int error = 0; 19761da177e4SLinus Torvalds 19778869477aSEric Paris address &= PAGE_MASK; 19780a1d5299SJann Horn if (address < mmap_min_addr) 19790a1d5299SJann Horn return -EPERM; 19808869477aSEric Paris 19811be7107fSHugh Dickins /* Enforce stack_guard_gap */ 1982763ecb03SLiam R. Howlett prev = mas_prev(&mas, 0); 19831be7107fSHugh Dickins /* Check that both stack segments have the same anon_vma? */ 198432e4e6d5SOleg Nesterov if (prev && !(prev->vm_flags & VM_GROWSDOWN) && 19853122e80eSAnshuman Khandual vma_is_accessible(prev)) { 198632e4e6d5SOleg Nesterov if (address - prev->vm_end < stack_guard_gap) 198732e4e6d5SOleg Nesterov return -ENOMEM; 19881be7107fSHugh Dickins } 19891be7107fSHugh Dickins 1990c5d5546eSVernon Yang if (mas_preallocate(&mas, GFP_KERNEL)) 199112352d3cSKonstantin Khlebnikov return -ENOMEM; 19921da177e4SLinus Torvalds 1993d4af56c5SLiam R. Howlett /* We must make sure the anon_vma is allocated. */ 1994d4af56c5SLiam R. Howlett if (unlikely(anon_vma_prepare(vma))) { 1995d4af56c5SLiam R. Howlett mas_destroy(&mas); 1996d4af56c5SLiam R. Howlett return -ENOMEM; 1997d4af56c5SLiam R. Howlett } 1998d4af56c5SLiam R. Howlett 19991da177e4SLinus Torvalds /* 20001da177e4SLinus Torvalds * vma->vm_start/vm_end cannot change under us because the caller 2001c1e8d7c6SMichel Lespinasse * is required to hold the mmap_lock in read mode. We need the 20021da177e4SLinus Torvalds * anon_vma lock to serialize against concurrent expand_stacks. 20031da177e4SLinus Torvalds */ 200412352d3cSKonstantin Khlebnikov anon_vma_lock_write(vma->anon_vma); 20051da177e4SLinus Torvalds 20061da177e4SLinus Torvalds /* Somebody else might have raced and expanded it already */ 20071da177e4SLinus Torvalds if (address < vma->vm_start) { 20081da177e4SLinus Torvalds unsigned long size, grow; 20091da177e4SLinus Torvalds 20101da177e4SLinus Torvalds size = vma->vm_end - address; 20111da177e4SLinus Torvalds grow = (vma->vm_start - address) >> PAGE_SHIFT; 20121da177e4SLinus Torvalds 2013a626ca6aSLinus Torvalds error = -ENOMEM; 2014a626ca6aSLinus Torvalds if (grow <= vma->vm_pgoff) { 20151da177e4SLinus Torvalds error = acct_stack_growth(vma, size, grow); 20161da177e4SLinus Torvalds if (!error) { 20174128997bSMichel Lespinasse /* 2018524e00b3SLiam R. Howlett * We only hold a shared mmap_lock lock here, so 2019524e00b3SLiam R. Howlett * we need to protect against concurrent vma 2020524e00b3SLiam R. Howlett * expansions. anon_vma_lock_write() doesn't 2021524e00b3SLiam R. Howlett * help here, as we don't guarantee that all 2022524e00b3SLiam R. Howlett * growable vmas in a mm share the same root 2023524e00b3SLiam R. Howlett * anon vma. So, we reuse mm->page_table_lock 2024524e00b3SLiam R. Howlett * to guard against concurrent vma expansions. 20254128997bSMichel Lespinasse */ 202609357814SOleg Nesterov spin_lock(&mm->page_table_lock); 202787e8827bSOleg Nesterov if (vma->vm_flags & VM_LOCKED) 202809357814SOleg Nesterov mm->locked_vm += grow; 202984638335SKonstantin Khlebnikov vm_stat_account(mm, vma->vm_flags, grow); 2030bf181b9fSMichel Lespinasse anon_vma_interval_tree_pre_update_vma(vma); 20311da177e4SLinus Torvalds vma->vm_start = address; 20321da177e4SLinus Torvalds vma->vm_pgoff -= grow; 2033d4af56c5SLiam R. Howlett /* Overwrite old entry in mtree. */ 2034*fbcc3104SLiam R. Howlett mas_set_range(&mas, address, vma->vm_end - 1); 2035*fbcc3104SLiam R. Howlett mas_store_prealloc(&mas, vma); 2036bf181b9fSMichel Lespinasse anon_vma_interval_tree_post_update_vma(vma); 203709357814SOleg Nesterov spin_unlock(&mm->page_table_lock); 20384128997bSMichel Lespinasse 20393af9e859SEric B Munson perf_event_mmap(vma); 20401da177e4SLinus Torvalds } 20411da177e4SLinus Torvalds } 2042a626ca6aSLinus Torvalds } 204312352d3cSKonstantin Khlebnikov anon_vma_unlock_write(vma->anon_vma); 2044c791576cSYang Shi khugepaged_enter_vma(vma, vma->vm_flags); 2045d4af56c5SLiam R. Howlett mas_destroy(&mas); 20461da177e4SLinus Torvalds return error; 20471da177e4SLinus Torvalds } 20481da177e4SLinus Torvalds 20491be7107fSHugh Dickins /* enforced gap between the expanding stack and other mappings. */ 20501be7107fSHugh Dickins unsigned long stack_guard_gap = 256UL<<PAGE_SHIFT; 20511be7107fSHugh Dickins 20521be7107fSHugh Dickins static int __init cmdline_parse_stack_guard_gap(char *p) 20531be7107fSHugh Dickins { 20541be7107fSHugh Dickins unsigned long val; 20551be7107fSHugh Dickins char *endptr; 20561be7107fSHugh Dickins 20571be7107fSHugh Dickins val = simple_strtoul(p, &endptr, 10); 20581be7107fSHugh Dickins if (!*endptr) 20591be7107fSHugh Dickins stack_guard_gap = val << PAGE_SHIFT; 20601be7107fSHugh Dickins 2061e6d09493SRandy Dunlap return 1; 20621be7107fSHugh Dickins } 20631be7107fSHugh Dickins __setup("stack_guard_gap=", cmdline_parse_stack_guard_gap); 20641be7107fSHugh Dickins 2065b6a2fea3SOllie Wild #ifdef CONFIG_STACK_GROWSUP 2066b6a2fea3SOllie Wild int expand_stack(struct vm_area_struct *vma, unsigned long address) 2067b6a2fea3SOllie Wild { 2068b6a2fea3SOllie Wild return expand_upwards(vma, address); 2069b6a2fea3SOllie Wild } 2070b6a2fea3SOllie Wild 2071b6a2fea3SOllie Wild struct vm_area_struct * 2072b6a2fea3SOllie Wild find_extend_vma(struct mm_struct *mm, unsigned long addr) 2073b6a2fea3SOllie Wild { 2074b6a2fea3SOllie Wild struct vm_area_struct *vma, *prev; 2075b6a2fea3SOllie Wild 2076b6a2fea3SOllie Wild addr &= PAGE_MASK; 2077b6a2fea3SOllie Wild vma = find_vma_prev(mm, addr, &prev); 2078b6a2fea3SOllie Wild if (vma && (vma->vm_start <= addr)) 2079b6a2fea3SOllie Wild return vma; 20804d45e75aSJann Horn if (!prev || expand_stack(prev, addr)) 2081b6a2fea3SOllie Wild return NULL; 2082cea10a19SMichel Lespinasse if (prev->vm_flags & VM_LOCKED) 2083fc05f566SKirill A. Shutemov populate_vma_page_range(prev, addr, prev->vm_end, NULL); 2084b6a2fea3SOllie Wild return prev; 2085b6a2fea3SOllie Wild } 2086b6a2fea3SOllie Wild #else 2087b6a2fea3SOllie Wild int expand_stack(struct vm_area_struct *vma, unsigned long address) 2088b6a2fea3SOllie Wild { 2089b6a2fea3SOllie Wild return expand_downwards(vma, address); 2090b6a2fea3SOllie Wild } 2091b6a2fea3SOllie Wild 20921da177e4SLinus Torvalds struct vm_area_struct * 20931da177e4SLinus Torvalds find_extend_vma(struct mm_struct *mm, unsigned long addr) 20941da177e4SLinus Torvalds { 20951da177e4SLinus Torvalds struct vm_area_struct *vma; 20961da177e4SLinus Torvalds unsigned long start; 20971da177e4SLinus Torvalds 20981da177e4SLinus Torvalds addr &= PAGE_MASK; 20991da177e4SLinus Torvalds vma = find_vma(mm, addr); 21001da177e4SLinus Torvalds if (!vma) 21011da177e4SLinus Torvalds return NULL; 21021da177e4SLinus Torvalds if (vma->vm_start <= addr) 21031da177e4SLinus Torvalds return vma; 21041da177e4SLinus Torvalds if (!(vma->vm_flags & VM_GROWSDOWN)) 21051da177e4SLinus Torvalds return NULL; 21061da177e4SLinus Torvalds start = vma->vm_start; 21071da177e4SLinus Torvalds if (expand_stack(vma, addr)) 21081da177e4SLinus Torvalds return NULL; 2109cea10a19SMichel Lespinasse if (vma->vm_flags & VM_LOCKED) 2110fc05f566SKirill A. Shutemov populate_vma_page_range(vma, addr, start, NULL); 21111da177e4SLinus Torvalds return vma; 21121da177e4SLinus Torvalds } 21131da177e4SLinus Torvalds #endif 21141da177e4SLinus Torvalds 2115e1d6d01aSJesse Barnes EXPORT_SYMBOL_GPL(find_extend_vma); 2116e1d6d01aSJesse Barnes 21172c0b3814SHugh Dickins /* 2118763ecb03SLiam R. Howlett * Ok - we have the memory areas we should free on a maple tree so release them, 2119763ecb03SLiam R. Howlett * and do the vma updates. 21201da177e4SLinus Torvalds * 21212c0b3814SHugh Dickins * Called with the mm semaphore held. 21221da177e4SLinus Torvalds */ 2123763ecb03SLiam R. Howlett static inline void remove_mt(struct mm_struct *mm, struct ma_state *mas) 21241da177e4SLinus Torvalds { 21254f74d2c8SLinus Torvalds unsigned long nr_accounted = 0; 2126763ecb03SLiam R. Howlett struct vm_area_struct *vma; 21274f74d2c8SLinus Torvalds 2128365e9c87SHugh Dickins /* Update high watermark before we lower total_vm */ 2129365e9c87SHugh Dickins update_hiwater_vm(mm); 2130763ecb03SLiam R. Howlett mas_for_each(mas, vma, ULONG_MAX) { 2131ab50b8edSHugh Dickins long nrpages = vma_pages(vma); 21321da177e4SLinus Torvalds 21334f74d2c8SLinus Torvalds if (vma->vm_flags & VM_ACCOUNT) 21344f74d2c8SLinus Torvalds nr_accounted += nrpages; 213584638335SKonstantin Khlebnikov vm_stat_account(mm, vma->vm_flags, -nrpages); 2136763ecb03SLiam R. Howlett remove_vma(vma); 2137763ecb03SLiam R. Howlett } 21384f74d2c8SLinus Torvalds vm_unacct_memory(nr_accounted); 21391da177e4SLinus Torvalds validate_mm(mm); 21401da177e4SLinus Torvalds } 21411da177e4SLinus Torvalds 21421da177e4SLinus Torvalds /* 21431da177e4SLinus Torvalds * Get rid of page table information in the indicated region. 21441da177e4SLinus Torvalds * 2145f10df686SPaolo 'Blaisorblade' Giarrusso * Called with the mm semaphore held. 21461da177e4SLinus Torvalds */ 2147763ecb03SLiam R. Howlett static void unmap_region(struct mm_struct *mm, struct maple_tree *mt, 2148e0da382cSHugh Dickins struct vm_area_struct *vma, struct vm_area_struct *prev, 2149763ecb03SLiam R. Howlett struct vm_area_struct *next, 2150e0da382cSHugh Dickins unsigned long start, unsigned long end) 21511da177e4SLinus Torvalds { 2152d16dfc55SPeter Zijlstra struct mmu_gather tlb; 21531da177e4SLinus Torvalds 21541da177e4SLinus Torvalds lru_add_drain(); 2155a72afd87SWill Deacon tlb_gather_mmu(&tlb, mm); 2156365e9c87SHugh Dickins update_hiwater_rss(mm); 2157763ecb03SLiam R. Howlett unmap_vmas(&tlb, mt, vma, start, end); 2158763ecb03SLiam R. Howlett free_pgtables(&tlb, mt, vma, prev ? prev->vm_end : FIRST_USER_ADDRESS, 21596ee8630eSHugh Dickins next ? next->vm_start : USER_PGTABLES_CEILING); 2160ae8eba8bSWill Deacon tlb_finish_mmu(&tlb); 21611da177e4SLinus Torvalds } 21621da177e4SLinus Torvalds 21631da177e4SLinus Torvalds /* 2164def5efe0SDavid Rientjes * __split_vma() bypasses sysctl_max_map_count checking. We use this where it 2165def5efe0SDavid Rientjes * has already been checked or doesn't make sense to fail. 21661da177e4SLinus Torvalds */ 21679760ebffSLiam R. Howlett int __split_vma(struct vma_iterator *vmi, struct vm_area_struct *vma, 21681da177e4SLinus Torvalds unsigned long addr, int new_below) 21691da177e4SLinus Torvalds { 21701da177e4SLinus Torvalds struct vm_area_struct *new; 2171e3975891SChen Gang int err; 21729760ebffSLiam R. Howlett unsigned long end = vma->vm_end; 21739760ebffSLiam R. Howlett 21749760ebffSLiam R. Howlett validate_mm_mt(vma->vm_mm); 21751da177e4SLinus Torvalds 2176dd3b614fSDmitry Safonov if (vma->vm_ops && vma->vm_ops->may_split) { 2177dd3b614fSDmitry Safonov err = vma->vm_ops->may_split(vma, addr); 217831383c68SDan Williams if (err) 217931383c68SDan Williams return err; 218031383c68SDan Williams } 21811da177e4SLinus Torvalds 21823928d4f5SLinus Torvalds new = vm_area_dup(vma); 21831da177e4SLinus Torvalds if (!new) 2184e3975891SChen Gang return -ENOMEM; 21851da177e4SLinus Torvalds 21861da177e4SLinus Torvalds if (new_below) 21871da177e4SLinus Torvalds new->vm_end = addr; 21881da177e4SLinus Torvalds else { 21891da177e4SLinus Torvalds new->vm_start = addr; 21901da177e4SLinus Torvalds new->vm_pgoff += ((addr - vma->vm_start) >> PAGE_SHIFT); 21911da177e4SLinus Torvalds } 21921da177e4SLinus Torvalds 2193ef0855d3SOleg Nesterov err = vma_dup_policy(vma, new); 2194ef0855d3SOleg Nesterov if (err) 21955beb4930SRik van Riel goto out_free_vma; 21961da177e4SLinus Torvalds 2197c4ea95d7SDaniel Forrest err = anon_vma_clone(new, vma); 2198c4ea95d7SDaniel Forrest if (err) 21995beb4930SRik van Riel goto out_free_mpol; 22005beb4930SRik van Riel 2201e9714acfSKonstantin Khlebnikov if (new->vm_file) 22021da177e4SLinus Torvalds get_file(new->vm_file); 22031da177e4SLinus Torvalds 22041da177e4SLinus Torvalds if (new->vm_ops && new->vm_ops->open) 22051da177e4SLinus Torvalds new->vm_ops->open(new); 22061da177e4SLinus Torvalds 22071da177e4SLinus Torvalds if (new_below) 22085beb4930SRik van Riel err = vma_adjust(vma, addr, vma->vm_end, vma->vm_pgoff + 22091da177e4SLinus Torvalds ((addr - new->vm_start) >> PAGE_SHIFT), new); 22101da177e4SLinus Torvalds else 22115beb4930SRik van Riel err = vma_adjust(vma, vma->vm_start, addr, vma->vm_pgoff, new); 22121da177e4SLinus Torvalds 22135beb4930SRik van Riel /* Success. */ 22149760ebffSLiam R. Howlett if (!err) { 22159760ebffSLiam R. Howlett vma_iter_set(vmi, end); 22161da177e4SLinus Torvalds return 0; 22179760ebffSLiam R. Howlett } 22185beb4930SRik van Riel 2219d4af56c5SLiam R. Howlett /* Avoid vm accounting in close() operation */ 2220d4af56c5SLiam R. Howlett new->vm_start = new->vm_end; 2221d4af56c5SLiam R. Howlett new->vm_pgoff = 0; 22225beb4930SRik van Riel /* Clean everything up if vma_adjust failed. */ 222358927533SRik van Riel if (new->vm_ops && new->vm_ops->close) 22245beb4930SRik van Riel new->vm_ops->close(new); 2225e9714acfSKonstantin Khlebnikov if (new->vm_file) 22265beb4930SRik van Riel fput(new->vm_file); 22272aeadc30SAndrea Arcangeli unlink_anon_vmas(new); 22285beb4930SRik van Riel out_free_mpol: 2229ef0855d3SOleg Nesterov mpol_put(vma_policy(new)); 22305beb4930SRik van Riel out_free_vma: 22313928d4f5SLinus Torvalds vm_area_free(new); 22329760ebffSLiam R. Howlett validate_mm_mt(vma->vm_mm); 22335beb4930SRik van Riel return err; 22341da177e4SLinus Torvalds } 22351da177e4SLinus Torvalds 2236659ace58SKOSAKI Motohiro /* 2237659ace58SKOSAKI Motohiro * Split a vma into two pieces at address 'addr', a new vma is allocated 2238659ace58SKOSAKI Motohiro * either for the first part or the tail. 2239659ace58SKOSAKI Motohiro */ 22409760ebffSLiam R. Howlett int split_vma(struct vma_iterator *vmi, struct vm_area_struct *vma, 2241659ace58SKOSAKI Motohiro unsigned long addr, int new_below) 2242659ace58SKOSAKI Motohiro { 22439760ebffSLiam R. Howlett if (vma->vm_mm->map_count >= sysctl_max_map_count) 2244659ace58SKOSAKI Motohiro return -ENOMEM; 2245659ace58SKOSAKI Motohiro 22469760ebffSLiam R. Howlett return __split_vma(vmi, vma, addr, new_below); 2247f2ebfe43SLiam R. Howlett } 2248f2ebfe43SLiam R. Howlett 2249763ecb03SLiam R. Howlett static inline int munmap_sidetree(struct vm_area_struct *vma, 2250763ecb03SLiam R. Howlett struct ma_state *mas_detach) 22511da177e4SLinus Torvalds { 2252763ecb03SLiam R. Howlett mas_set_range(mas_detach, vma->vm_start, vma->vm_end - 1); 2253763ecb03SLiam R. Howlett if (mas_store_gfp(mas_detach, vma, GFP_KERNEL)) 2254763ecb03SLiam R. Howlett return -ENOMEM; 225511f9a21aSLiam R. Howlett 2256763ecb03SLiam R. Howlett if (vma->vm_flags & VM_LOCKED) 2257763ecb03SLiam R. Howlett vma->vm_mm->locked_vm -= vma_pages(vma); 225811f9a21aSLiam R. Howlett 2259763ecb03SLiam R. Howlett return 0; 226011f9a21aSLiam R. Howlett } 226111f9a21aSLiam R. Howlett 226211f9a21aSLiam R. Howlett /* 2263183654ceSLiam R. Howlett * do_vmi_align_munmap() - munmap the aligned region from @start to @end. 2264183654ceSLiam R. Howlett * @vmi: The vma iterator 226511f9a21aSLiam R. Howlett * @vma: The starting vm_area_struct 226611f9a21aSLiam R. Howlett * @mm: The mm_struct 226711f9a21aSLiam R. Howlett * @start: The aligned start address to munmap. 226811f9a21aSLiam R. Howlett * @end: The aligned end address to munmap. 226911f9a21aSLiam R. Howlett * @uf: The userfaultfd list_head 22708651a137SLorenzo Stoakes * @downgrade: Set to true to attempt a write downgrade of the mmap_lock 227111f9a21aSLiam R. Howlett * 227211f9a21aSLiam R. Howlett * If @downgrade is true, check return code for potential release of the lock. 227311f9a21aSLiam R. Howlett */ 227411f9a21aSLiam R. Howlett static int 2275183654ceSLiam R. Howlett do_vmi_align_munmap(struct vma_iterator *vmi, struct vm_area_struct *vma, 227611f9a21aSLiam R. Howlett struct mm_struct *mm, unsigned long start, 227711f9a21aSLiam R. Howlett unsigned long end, struct list_head *uf, bool downgrade) 227811f9a21aSLiam R. Howlett { 2279763ecb03SLiam R. Howlett struct vm_area_struct *prev, *next = NULL; 2280763ecb03SLiam R. Howlett struct maple_tree mt_detach; 2281763ecb03SLiam R. Howlett int count = 0; 2282d4af56c5SLiam R. Howlett int error = -ENOMEM; 2283763ecb03SLiam R. Howlett MA_STATE(mas_detach, &mt_detach, 0, 0); 2284763ecb03SLiam R. Howlett mt_init_flags(&mt_detach, MT_FLAGS_LOCK_EXTERN); 2285763ecb03SLiam R. Howlett mt_set_external_lock(&mt_detach, &mm->mmap_lock); 2286524e00b3SLiam R. Howlett 22871da177e4SLinus Torvalds /* 22881da177e4SLinus Torvalds * If we need to split any vma, do it now to save pain later. 22891da177e4SLinus Torvalds * 22901da177e4SLinus Torvalds * Note: mremap's move_vma VM_ACCOUNT handling assumes a partially 22911da177e4SLinus Torvalds * unmapped vm_area_struct will remain in use: so lower split_vma 22921da177e4SLinus Torvalds * places tmp vma above, and higher split_vma places tmp vma below. 22931da177e4SLinus Torvalds */ 2294763ecb03SLiam R. Howlett 2295763ecb03SLiam R. Howlett /* Does it split the first one? */ 2296146425a3SHugh Dickins if (start > vma->vm_start) { 2297659ace58SKOSAKI Motohiro 2298659ace58SKOSAKI Motohiro /* 2299659ace58SKOSAKI Motohiro * Make sure that map_count on return from munmap() will 2300659ace58SKOSAKI Motohiro * not exceed its limit; but let map_count go just above 2301659ace58SKOSAKI Motohiro * its limit temporarily, to help free resources as expected. 2302659ace58SKOSAKI Motohiro */ 2303659ace58SKOSAKI Motohiro if (end < vma->vm_end && mm->map_count >= sysctl_max_map_count) 2304d4af56c5SLiam R. Howlett goto map_count_exceeded; 2305659ace58SKOSAKI Motohiro 23069760ebffSLiam R. Howlett error = __split_vma(vmi, vma, start, 0); 23071da177e4SLinus Torvalds if (error) 2308763ecb03SLiam R. Howlett goto start_split_failed; 230911f9a21aSLiam R. Howlett 2310183654ceSLiam R. Howlett vma_iter_set(vmi, start); 2311183654ceSLiam R. Howlett vma = vma_find(vmi, end); 23121da177e4SLinus Torvalds } 23131da177e4SLinus Torvalds 2314183654ceSLiam R. Howlett prev = vma_prev(vmi); 2315763ecb03SLiam R. Howlett if (unlikely((!prev))) 2316183654ceSLiam R. Howlett vma_iter_set(vmi, start); 231711f9a21aSLiam R. Howlett 2318763ecb03SLiam R. Howlett /* 2319763ecb03SLiam R. Howlett * Detach a range of VMAs from the mm. Using next as a temp variable as 2320763ecb03SLiam R. Howlett * it is always overwritten. 2321763ecb03SLiam R. Howlett */ 2322183654ceSLiam R. Howlett for_each_vma_range(*vmi, next, end) { 2323763ecb03SLiam R. Howlett /* Does it split the end? */ 2324763ecb03SLiam R. Howlett if (next->vm_end > end) { 2325763ecb03SLiam R. Howlett struct vm_area_struct *split; 232611f9a21aSLiam R. Howlett 23279760ebffSLiam R. Howlett error = __split_vma(vmi, next, end, 1); 23281da177e4SLinus Torvalds if (error) 2329763ecb03SLiam R. Howlett goto end_split_failed; 233011f9a21aSLiam R. Howlett 2331183654ceSLiam R. Howlett vma_iter_set(vmi, end); 2332183654ceSLiam R. Howlett split = vma_prev(vmi); 2333763ecb03SLiam R. Howlett error = munmap_sidetree(split, &mas_detach); 2334763ecb03SLiam R. Howlett if (error) 2335763ecb03SLiam R. Howlett goto munmap_sidetree_failed; 2336763ecb03SLiam R. Howlett 2337763ecb03SLiam R. Howlett count++; 2338763ecb03SLiam R. Howlett if (vma == next) 2339763ecb03SLiam R. Howlett vma = split; 2340763ecb03SLiam R. Howlett break; 234111f9a21aSLiam R. Howlett } 2342763ecb03SLiam R. Howlett error = munmap_sidetree(next, &mas_detach); 2343763ecb03SLiam R. Howlett if (error) 2344763ecb03SLiam R. Howlett goto munmap_sidetree_failed; 2345763ecb03SLiam R. Howlett 2346763ecb03SLiam R. Howlett count++; 2347763ecb03SLiam R. Howlett #ifdef CONFIG_DEBUG_VM_MAPLE_TREE 2348763ecb03SLiam R. Howlett BUG_ON(next->vm_start < start); 2349763ecb03SLiam R. Howlett BUG_ON(next->vm_start > end); 2350763ecb03SLiam R. Howlett #endif 2351763ecb03SLiam R. Howlett } 2352763ecb03SLiam R. Howlett 2353763ecb03SLiam R. Howlett if (!next) 2354183654ceSLiam R. Howlett next = vma_next(vmi); 23551da177e4SLinus Torvalds 23562376dd7cSAndrea Arcangeli if (unlikely(uf)) { 23572376dd7cSAndrea Arcangeli /* 23582376dd7cSAndrea Arcangeli * If userfaultfd_unmap_prep returns an error the vmas 2359f0953a1bSIngo Molnar * will remain split, but userland will get a 23602376dd7cSAndrea Arcangeli * highly unexpected error anyway. This is no 23612376dd7cSAndrea Arcangeli * different than the case where the first of the two 23622376dd7cSAndrea Arcangeli * __split_vma fails, but we don't undo the first 23632376dd7cSAndrea Arcangeli * split, despite we could. This is unlikely enough 23642376dd7cSAndrea Arcangeli * failure that it's not worth optimizing it for. 23652376dd7cSAndrea Arcangeli */ 236669dbe6daSLiam R. Howlett error = userfaultfd_unmap_prep(mm, start, end, uf); 236711f9a21aSLiam R. Howlett 23682376dd7cSAndrea Arcangeli if (error) 2369d4af56c5SLiam R. Howlett goto userfaultfd_error; 23702376dd7cSAndrea Arcangeli } 23712376dd7cSAndrea Arcangeli 2372763ecb03SLiam R. Howlett #if defined(CONFIG_DEBUG_VM_MAPLE_TREE) 2373763ecb03SLiam R. Howlett /* Make sure no VMAs are about to be lost. */ 2374763ecb03SLiam R. Howlett { 2375763ecb03SLiam R. Howlett MA_STATE(test, &mt_detach, start, end - 1); 2376763ecb03SLiam R. Howlett struct vm_area_struct *vma_mas, *vma_test; 2377763ecb03SLiam R. Howlett int test_count = 0; 2378763ecb03SLiam R. Howlett 2379183654ceSLiam R. Howlett vma_iter_set(vmi, start); 2380763ecb03SLiam R. Howlett rcu_read_lock(); 2381763ecb03SLiam R. Howlett vma_test = mas_find(&test, end - 1); 2382183654ceSLiam R. Howlett for_each_vma_range(*vmi, vma_mas, end) { 2383763ecb03SLiam R. Howlett BUG_ON(vma_mas != vma_test); 2384763ecb03SLiam R. Howlett test_count++; 2385763ecb03SLiam R. Howlett vma_test = mas_next(&test, end - 1); 2386763ecb03SLiam R. Howlett } 2387763ecb03SLiam R. Howlett rcu_read_unlock(); 2388763ecb03SLiam R. Howlett BUG_ON(count != test_count); 2389763ecb03SLiam R. Howlett } 2390763ecb03SLiam R. Howlett #endif 23910378c0a0SLiam R. Howlett /* Point of no return */ 2392183654ceSLiam R. Howlett vma_iter_set(vmi, start); 2393183654ceSLiam R. Howlett if (vma_iter_clear_gfp(vmi, start, end, GFP_KERNEL)) 23940378c0a0SLiam R. Howlett return -ENOMEM; 23950378c0a0SLiam R. Howlett 2396763ecb03SLiam R. Howlett mm->map_count -= count; 239711f9a21aSLiam R. Howlett /* 239811f9a21aSLiam R. Howlett * Do not downgrade mmap_lock if we are next to VM_GROWSDOWN or 239911f9a21aSLiam R. Howlett * VM_GROWSUP VMA. Such VMAs can change their size under 240011f9a21aSLiam R. Howlett * down_read(mmap_lock) and collide with the VMA we are about to unmap. 240111f9a21aSLiam R. Howlett */ 240211f9a21aSLiam R. Howlett if (downgrade) { 2403763ecb03SLiam R. Howlett if (next && (next->vm_flags & VM_GROWSDOWN)) 240411f9a21aSLiam R. Howlett downgrade = false; 240511f9a21aSLiam R. Howlett else if (prev && (prev->vm_flags & VM_GROWSUP)) 240611f9a21aSLiam R. Howlett downgrade = false; 240711f9a21aSLiam R. Howlett else 2408d8ed45c5SMichel Lespinasse mmap_write_downgrade(mm); 240911f9a21aSLiam R. Howlett } 2410dd2283f2SYang Shi 2411763ecb03SLiam R. Howlett unmap_region(mm, &mt_detach, vma, prev, next, start, end); 2412763ecb03SLiam R. Howlett /* Statistics and freeing VMAs */ 2413763ecb03SLiam R. Howlett mas_set(&mas_detach, start); 2414763ecb03SLiam R. Howlett remove_mt(mm, &mas_detach); 2415763ecb03SLiam R. Howlett __mt_destroy(&mt_detach); 24161da177e4SLinus Torvalds 2417524e00b3SLiam R. Howlett 2418524e00b3SLiam R. Howlett validate_mm(mm); 2419dd2283f2SYang Shi return downgrade ? 1 : 0; 2420d4af56c5SLiam R. Howlett 2421d4af56c5SLiam R. Howlett userfaultfd_error: 2422763ecb03SLiam R. Howlett munmap_sidetree_failed: 2423763ecb03SLiam R. Howlett end_split_failed: 2424763ecb03SLiam R. Howlett __mt_destroy(&mt_detach); 2425763ecb03SLiam R. Howlett start_split_failed: 2426763ecb03SLiam R. Howlett map_count_exceeded: 2427d4af56c5SLiam R. Howlett return error; 24281da177e4SLinus Torvalds } 24291da177e4SLinus Torvalds 243011f9a21aSLiam R. Howlett /* 2431183654ceSLiam R. Howlett * do_vmi_munmap() - munmap a given range. 2432183654ceSLiam R. Howlett * @vmi: The vma iterator 243311f9a21aSLiam R. Howlett * @mm: The mm_struct 243411f9a21aSLiam R. Howlett * @start: The start address to munmap 243511f9a21aSLiam R. Howlett * @len: The length of the range to munmap 243611f9a21aSLiam R. Howlett * @uf: The userfaultfd list_head 243711f9a21aSLiam R. Howlett * @downgrade: set to true if the user wants to attempt to write_downgrade the 24388651a137SLorenzo Stoakes * mmap_lock 243911f9a21aSLiam R. Howlett * 244011f9a21aSLiam R. Howlett * This function takes a @mas that is either pointing to the previous VMA or set 244111f9a21aSLiam R. Howlett * to MA_START and sets it up to remove the mapping(s). The @len will be 244211f9a21aSLiam R. Howlett * aligned and any arch_unmap work will be preformed. 244311f9a21aSLiam R. Howlett * 244411f9a21aSLiam R. Howlett * Returns: -EINVAL on failure, 1 on success and unlock, 0 otherwise. 244511f9a21aSLiam R. Howlett */ 2446183654ceSLiam R. Howlett int do_vmi_munmap(struct vma_iterator *vmi, struct mm_struct *mm, 244711f9a21aSLiam R. Howlett unsigned long start, size_t len, struct list_head *uf, 244811f9a21aSLiam R. Howlett bool downgrade) 244911f9a21aSLiam R. Howlett { 245011f9a21aSLiam R. Howlett unsigned long end; 245111f9a21aSLiam R. Howlett struct vm_area_struct *vma; 245211f9a21aSLiam R. Howlett 245311f9a21aSLiam R. Howlett if ((offset_in_page(start)) || start > TASK_SIZE || len > TASK_SIZE-start) 245411f9a21aSLiam R. Howlett return -EINVAL; 245511f9a21aSLiam R. Howlett 245611f9a21aSLiam R. Howlett end = start + PAGE_ALIGN(len); 245711f9a21aSLiam R. Howlett if (end == start) 245811f9a21aSLiam R. Howlett return -EINVAL; 245911f9a21aSLiam R. Howlett 246011f9a21aSLiam R. Howlett /* arch_unmap() might do unmaps itself. */ 246111f9a21aSLiam R. Howlett arch_unmap(mm, start, end); 246211f9a21aSLiam R. Howlett 246311f9a21aSLiam R. Howlett /* Find the first overlapping VMA */ 2464183654ceSLiam R. Howlett vma = vma_find(vmi, end); 246511f9a21aSLiam R. Howlett if (!vma) 246611f9a21aSLiam R. Howlett return 0; 246711f9a21aSLiam R. Howlett 2468183654ceSLiam R. Howlett return do_vmi_align_munmap(vmi, vma, mm, start, end, uf, downgrade); 246911f9a21aSLiam R. Howlett } 247011f9a21aSLiam R. Howlett 247111f9a21aSLiam R. Howlett /* do_munmap() - Wrapper function for non-maple tree aware do_munmap() calls. 247211f9a21aSLiam R. Howlett * @mm: The mm_struct 247311f9a21aSLiam R. Howlett * @start: The start address to munmap 247411f9a21aSLiam R. Howlett * @len: The length to be munmapped. 247511f9a21aSLiam R. Howlett * @uf: The userfaultfd list_head 247611f9a21aSLiam R. Howlett */ 2477dd2283f2SYang Shi int do_munmap(struct mm_struct *mm, unsigned long start, size_t len, 2478dd2283f2SYang Shi struct list_head *uf) 2479dd2283f2SYang Shi { 2480183654ceSLiam R. Howlett VMA_ITERATOR(vmi, mm, start); 248111f9a21aSLiam R. Howlett 2482183654ceSLiam R. Howlett return do_vmi_munmap(&vmi, mm, start, len, uf, false); 2483dd2283f2SYang Shi } 2484dd2283f2SYang Shi 2485e99668a5SLiam R. Howlett unsigned long mmap_region(struct file *file, unsigned long addr, 2486e99668a5SLiam R. Howlett unsigned long len, vm_flags_t vm_flags, unsigned long pgoff, 2487e99668a5SLiam R. Howlett struct list_head *uf) 2488e99668a5SLiam R. Howlett { 2489e99668a5SLiam R. Howlett struct mm_struct *mm = current->mm; 2490e99668a5SLiam R. Howlett struct vm_area_struct *vma = NULL; 2491e99668a5SLiam R. Howlett struct vm_area_struct *next, *prev, *merge; 2492e99668a5SLiam R. Howlett pgoff_t pglen = len >> PAGE_SHIFT; 2493e99668a5SLiam R. Howlett unsigned long charged = 0; 2494e99668a5SLiam R. Howlett unsigned long end = addr + len; 2495e99668a5SLiam R. Howlett unsigned long merge_start = addr, merge_end = end; 2496e99668a5SLiam R. Howlett pgoff_t vm_pgoff; 2497e99668a5SLiam R. Howlett int error; 2498183654ceSLiam R. Howlett VMA_ITERATOR(vmi, mm, addr); 2499e99668a5SLiam R. Howlett 2500e99668a5SLiam R. Howlett /* Check against address space limit. */ 2501e99668a5SLiam R. Howlett if (!may_expand_vm(mm, vm_flags, len >> PAGE_SHIFT)) { 2502e99668a5SLiam R. Howlett unsigned long nr_pages; 2503e99668a5SLiam R. Howlett 2504e99668a5SLiam R. Howlett /* 2505e99668a5SLiam R. Howlett * MAP_FIXED may remove pages of mappings that intersects with 2506e99668a5SLiam R. Howlett * requested mapping. Account for the pages it would unmap. 2507e99668a5SLiam R. Howlett */ 2508e99668a5SLiam R. Howlett nr_pages = count_vma_pages_range(mm, addr, end); 2509e99668a5SLiam R. Howlett 2510e99668a5SLiam R. Howlett if (!may_expand_vm(mm, vm_flags, 2511e99668a5SLiam R. Howlett (len >> PAGE_SHIFT) - nr_pages)) 2512e99668a5SLiam R. Howlett return -ENOMEM; 2513e99668a5SLiam R. Howlett } 2514e99668a5SLiam R. Howlett 2515e99668a5SLiam R. Howlett /* Unmap any existing mapping in the area */ 2516183654ceSLiam R. Howlett if (do_vmi_munmap(&vmi, mm, addr, len, uf, false)) 2517e99668a5SLiam R. Howlett return -ENOMEM; 2518e99668a5SLiam R. Howlett 2519e99668a5SLiam R. Howlett /* 2520e99668a5SLiam R. Howlett * Private writable mapping: check memory availability 2521e99668a5SLiam R. Howlett */ 2522e99668a5SLiam R. Howlett if (accountable_mapping(file, vm_flags)) { 2523e99668a5SLiam R. Howlett charged = len >> PAGE_SHIFT; 2524e99668a5SLiam R. Howlett if (security_vm_enough_memory_mm(mm, charged)) 2525e99668a5SLiam R. Howlett return -ENOMEM; 2526e99668a5SLiam R. Howlett vm_flags |= VM_ACCOUNT; 2527e99668a5SLiam R. Howlett } 2528e99668a5SLiam R. Howlett 2529183654ceSLiam R. Howlett next = vma_next(&vmi); 2530183654ceSLiam R. Howlett prev = vma_prev(&vmi); 2531e99668a5SLiam R. Howlett if (vm_flags & VM_SPECIAL) 2532e99668a5SLiam R. Howlett goto cannot_expand; 2533e99668a5SLiam R. Howlett 2534e99668a5SLiam R. Howlett /* Attempt to expand an old mapping */ 2535e99668a5SLiam R. Howlett /* Check next */ 2536e99668a5SLiam R. Howlett if (next && next->vm_start == end && !vma_policy(next) && 2537e99668a5SLiam R. Howlett can_vma_merge_before(next, vm_flags, NULL, file, pgoff+pglen, 2538e99668a5SLiam R. Howlett NULL_VM_UFFD_CTX, NULL)) { 2539e99668a5SLiam R. Howlett merge_end = next->vm_end; 2540e99668a5SLiam R. Howlett vma = next; 2541e99668a5SLiam R. Howlett vm_pgoff = next->vm_pgoff - pglen; 2542e99668a5SLiam R. Howlett } 2543e99668a5SLiam R. Howlett 2544e99668a5SLiam R. Howlett /* Check prev */ 2545e99668a5SLiam R. Howlett if (prev && prev->vm_end == addr && !vma_policy(prev) && 2546e99668a5SLiam R. Howlett (vma ? can_vma_merge_after(prev, vm_flags, vma->anon_vma, file, 2547e99668a5SLiam R. Howlett pgoff, vma->vm_userfaultfd_ctx, NULL) : 2548e99668a5SLiam R. Howlett can_vma_merge_after(prev, vm_flags, NULL, file, pgoff, 2549e99668a5SLiam R. Howlett NULL_VM_UFFD_CTX, NULL))) { 2550e99668a5SLiam R. Howlett merge_start = prev->vm_start; 2551e99668a5SLiam R. Howlett vma = prev; 2552e99668a5SLiam R. Howlett vm_pgoff = prev->vm_pgoff; 2553e99668a5SLiam R. Howlett } 2554e99668a5SLiam R. Howlett 2555e99668a5SLiam R. Howlett 2556e99668a5SLiam R. Howlett /* Actually expand, if possible */ 2557e99668a5SLiam R. Howlett if (vma && 25583c441ab7SLiam R. Howlett !vma_expand(&vmi, vma, merge_start, merge_end, vm_pgoff, next)) { 2559e99668a5SLiam R. Howlett khugepaged_enter_vma(vma, vm_flags); 2560e99668a5SLiam R. Howlett goto expanded; 2561e99668a5SLiam R. Howlett } 2562e99668a5SLiam R. Howlett 2563e99668a5SLiam R. Howlett cannot_expand: 2564e99668a5SLiam R. Howlett /* 2565e99668a5SLiam R. Howlett * Determine the object being mapped and call the appropriate 2566e99668a5SLiam R. Howlett * specific mapper. the address has already been validated, but 2567e99668a5SLiam R. Howlett * not unmapped, but the maps are removed from the list. 2568e99668a5SLiam R. Howlett */ 2569e99668a5SLiam R. Howlett vma = vm_area_alloc(mm); 2570e99668a5SLiam R. Howlett if (!vma) { 2571e99668a5SLiam R. Howlett error = -ENOMEM; 2572e99668a5SLiam R. Howlett goto unacct_error; 2573e99668a5SLiam R. Howlett } 2574e99668a5SLiam R. Howlett 2575e99668a5SLiam R. Howlett vma->vm_start = addr; 2576e99668a5SLiam R. Howlett vma->vm_end = end; 2577e99668a5SLiam R. Howlett vma->vm_flags = vm_flags; 2578e99668a5SLiam R. Howlett vma->vm_page_prot = vm_get_page_prot(vm_flags); 2579e99668a5SLiam R. Howlett vma->vm_pgoff = pgoff; 2580e99668a5SLiam R. Howlett 2581e99668a5SLiam R. Howlett if (file) { 2582e99668a5SLiam R. Howlett if (vm_flags & VM_SHARED) { 2583e99668a5SLiam R. Howlett error = mapping_map_writable(file->f_mapping); 2584e99668a5SLiam R. Howlett if (error) 2585e99668a5SLiam R. Howlett goto free_vma; 2586e99668a5SLiam R. Howlett } 2587e99668a5SLiam R. Howlett 2588e99668a5SLiam R. Howlett vma->vm_file = get_file(file); 2589e99668a5SLiam R. Howlett error = call_mmap(file, vma); 2590e99668a5SLiam R. Howlett if (error) 2591e99668a5SLiam R. Howlett goto unmap_and_free_vma; 2592e99668a5SLiam R. Howlett 2593a57b7051SLiam Howlett /* 2594a57b7051SLiam Howlett * Expansion is handled above, merging is handled below. 2595a57b7051SLiam Howlett * Drivers should not alter the address of the VMA. 2596e99668a5SLiam R. Howlett */ 2597a57b7051SLiam Howlett if (WARN_ON((addr != vma->vm_start))) { 2598a57b7051SLiam Howlett error = -EINVAL; 2599a57b7051SLiam Howlett goto close_and_free_vma; 2600a57b7051SLiam Howlett } 2601183654ceSLiam R. Howlett vma_iter_set(&vmi, addr); 2602e99668a5SLiam R. Howlett 2603e99668a5SLiam R. Howlett /* 2604e99668a5SLiam R. Howlett * If vm_flags changed after call_mmap(), we should try merge 2605e99668a5SLiam R. Howlett * vma again as we may succeed this time. 2606e99668a5SLiam R. Howlett */ 2607e99668a5SLiam R. Howlett if (unlikely(vm_flags != vma->vm_flags && prev)) { 26089760ebffSLiam R. Howlett merge = vma_merge(&vmi, mm, prev, vma->vm_start, 26099760ebffSLiam R. Howlett vma->vm_end, vma->vm_flags, NULL, 26109760ebffSLiam R. Howlett vma->vm_file, vma->vm_pgoff, NULL, 26119760ebffSLiam R. Howlett NULL_VM_UFFD_CTX, NULL); 2612e99668a5SLiam R. Howlett if (merge) { 2613e99668a5SLiam R. Howlett /* 2614e99668a5SLiam R. Howlett * ->mmap() can change vma->vm_file and fput 2615e99668a5SLiam R. Howlett * the original file. So fput the vma->vm_file 2616e99668a5SLiam R. Howlett * here or we would add an extra fput for file 2617e99668a5SLiam R. Howlett * and cause general protection fault 2618e99668a5SLiam R. Howlett * ultimately. 2619e99668a5SLiam R. Howlett */ 2620e99668a5SLiam R. Howlett fput(vma->vm_file); 2621e99668a5SLiam R. Howlett vm_area_free(vma); 2622e99668a5SLiam R. Howlett vma = merge; 2623e99668a5SLiam R. Howlett /* Update vm_flags to pick up the change. */ 2624e99668a5SLiam R. Howlett vm_flags = vma->vm_flags; 2625e99668a5SLiam R. Howlett goto unmap_writable; 2626e99668a5SLiam R. Howlett } 2627e99668a5SLiam R. Howlett } 2628e99668a5SLiam R. Howlett 2629e99668a5SLiam R. Howlett vm_flags = vma->vm_flags; 2630e99668a5SLiam R. Howlett } else if (vm_flags & VM_SHARED) { 2631e99668a5SLiam R. Howlett error = shmem_zero_setup(vma); 2632e99668a5SLiam R. Howlett if (error) 2633e99668a5SLiam R. Howlett goto free_vma; 2634e99668a5SLiam R. Howlett } else { 2635e99668a5SLiam R. Howlett vma_set_anonymous(vma); 2636e99668a5SLiam R. Howlett } 2637e99668a5SLiam R. Howlett 2638b507808eSJoey Gouly if (map_deny_write_exec(vma, vma->vm_flags)) { 2639b507808eSJoey Gouly error = -EACCES; 2640b507808eSJoey Gouly if (file) 2641b507808eSJoey Gouly goto close_and_free_vma; 2642b507808eSJoey Gouly else if (vma->vm_file) 2643b507808eSJoey Gouly goto unmap_and_free_vma; 2644b507808eSJoey Gouly else 2645b507808eSJoey Gouly goto free_vma; 2646b507808eSJoey Gouly } 2647b507808eSJoey Gouly 2648e99668a5SLiam R. Howlett /* Allow architectures to sanity-check the vm_flags */ 2649e99668a5SLiam R. Howlett if (!arch_validate_flags(vma->vm_flags)) { 2650e99668a5SLiam R. Howlett error = -EINVAL; 2651e99668a5SLiam R. Howlett if (file) 2652deb0f656SCarlos Llamas goto close_and_free_vma; 2653cc674ab3SLi Zetao else if (vma->vm_file) 2654cc674ab3SLi Zetao goto unmap_and_free_vma; 2655e99668a5SLiam R. Howlett else 2656e99668a5SLiam R. Howlett goto free_vma; 2657e99668a5SLiam R. Howlett } 2658e99668a5SLiam R. Howlett 2659183654ceSLiam R. Howlett if (vma_iter_prealloc(&vmi)) { 2660e99668a5SLiam R. Howlett error = -ENOMEM; 2661e99668a5SLiam R. Howlett if (file) 26625789151eSMike Kravetz goto close_and_free_vma; 2663cc674ab3SLi Zetao else if (vma->vm_file) 2664cc674ab3SLi Zetao goto unmap_and_free_vma; 2665e99668a5SLiam R. Howlett else 2666e99668a5SLiam R. Howlett goto free_vma; 2667e99668a5SLiam R. Howlett } 2668e99668a5SLiam R. Howlett 2669e99668a5SLiam R. Howlett if (vma->vm_file) 2670e99668a5SLiam R. Howlett i_mmap_lock_write(vma->vm_file->f_mapping); 2671e99668a5SLiam R. Howlett 2672183654ceSLiam R. Howlett vma_iter_store(&vmi, vma); 2673e99668a5SLiam R. Howlett mm->map_count++; 2674e99668a5SLiam R. Howlett if (vma->vm_file) { 2675e99668a5SLiam R. Howlett if (vma->vm_flags & VM_SHARED) 2676e99668a5SLiam R. Howlett mapping_allow_writable(vma->vm_file->f_mapping); 2677e99668a5SLiam R. Howlett 2678e99668a5SLiam R. Howlett flush_dcache_mmap_lock(vma->vm_file->f_mapping); 2679e99668a5SLiam R. Howlett vma_interval_tree_insert(vma, &vma->vm_file->f_mapping->i_mmap); 2680e99668a5SLiam R. Howlett flush_dcache_mmap_unlock(vma->vm_file->f_mapping); 2681e99668a5SLiam R. Howlett i_mmap_unlock_write(vma->vm_file->f_mapping); 2682e99668a5SLiam R. Howlett } 2683e99668a5SLiam R. Howlett 2684e99668a5SLiam R. Howlett /* 2685e99668a5SLiam R. Howlett * vma_merge() calls khugepaged_enter_vma() either, the below 2686e99668a5SLiam R. Howlett * call covers the non-merge case. 2687e99668a5SLiam R. Howlett */ 2688e99668a5SLiam R. Howlett khugepaged_enter_vma(vma, vma->vm_flags); 2689e99668a5SLiam R. Howlett 2690e99668a5SLiam R. Howlett /* Once vma denies write, undo our temporary denial count */ 2691e99668a5SLiam R. Howlett unmap_writable: 2692e99668a5SLiam R. Howlett if (file && vm_flags & VM_SHARED) 2693e99668a5SLiam R. Howlett mapping_unmap_writable(file->f_mapping); 2694e99668a5SLiam R. Howlett file = vma->vm_file; 2695e99668a5SLiam R. Howlett expanded: 2696e99668a5SLiam R. Howlett perf_event_mmap(vma); 2697e99668a5SLiam R. Howlett 2698e99668a5SLiam R. Howlett vm_stat_account(mm, vm_flags, len >> PAGE_SHIFT); 2699e99668a5SLiam R. Howlett if (vm_flags & VM_LOCKED) { 2700e99668a5SLiam R. Howlett if ((vm_flags & VM_SPECIAL) || vma_is_dax(vma) || 2701e99668a5SLiam R. Howlett is_vm_hugetlb_page(vma) || 2702e99668a5SLiam R. Howlett vma == get_gate_vma(current->mm)) 2703e99668a5SLiam R. Howlett vma->vm_flags &= VM_LOCKED_CLEAR_MASK; 2704e99668a5SLiam R. Howlett else 2705e99668a5SLiam R. Howlett mm->locked_vm += (len >> PAGE_SHIFT); 2706e99668a5SLiam R. Howlett } 2707e99668a5SLiam R. Howlett 2708e99668a5SLiam R. Howlett if (file) 2709e99668a5SLiam R. Howlett uprobe_mmap(vma); 2710e99668a5SLiam R. Howlett 2711e99668a5SLiam R. Howlett /* 2712e99668a5SLiam R. Howlett * New (or expanded) vma always get soft dirty status. 2713e99668a5SLiam R. Howlett * Otherwise user-space soft-dirty page tracker won't 2714e99668a5SLiam R. Howlett * be able to distinguish situation when vma area unmapped, 2715e99668a5SLiam R. Howlett * then new mapped in-place (which must be aimed as 2716e99668a5SLiam R. Howlett * a completely new data area). 2717e99668a5SLiam R. Howlett */ 2718e99668a5SLiam R. Howlett vma->vm_flags |= VM_SOFTDIRTY; 2719e99668a5SLiam R. Howlett 2720e99668a5SLiam R. Howlett vma_set_page_prot(vma); 2721e99668a5SLiam R. Howlett 2722e99668a5SLiam R. Howlett validate_mm(mm); 2723e99668a5SLiam R. Howlett return addr; 2724e99668a5SLiam R. Howlett 2725deb0f656SCarlos Llamas close_and_free_vma: 2726deb0f656SCarlos Llamas if (vma->vm_ops && vma->vm_ops->close) 2727deb0f656SCarlos Llamas vma->vm_ops->close(vma); 2728e99668a5SLiam R. Howlett unmap_and_free_vma: 2729e99668a5SLiam R. Howlett fput(vma->vm_file); 2730e99668a5SLiam R. Howlett vma->vm_file = NULL; 2731e99668a5SLiam R. Howlett 2732e99668a5SLiam R. Howlett /* Undo any partial mapping done by a device driver. */ 2733183654ceSLiam R. Howlett unmap_region(mm, &mm->mm_mt, vma, prev, next, vma->vm_start, vma->vm_end); 2734cc674ab3SLi Zetao if (file && (vm_flags & VM_SHARED)) 2735e99668a5SLiam R. Howlett mapping_unmap_writable(file->f_mapping); 2736e99668a5SLiam R. Howlett free_vma: 2737e99668a5SLiam R. Howlett vm_area_free(vma); 2738e99668a5SLiam R. Howlett unacct_error: 2739e99668a5SLiam R. Howlett if (charged) 2740e99668a5SLiam R. Howlett vm_unacct_memory(charged); 2741e99668a5SLiam R. Howlett validate_mm(mm); 2742e99668a5SLiam R. Howlett return error; 2743e99668a5SLiam R. Howlett } 2744e99668a5SLiam R. Howlett 2745dd2283f2SYang Shi static int __vm_munmap(unsigned long start, size_t len, bool downgrade) 2746a46ef99dSLinus Torvalds { 2747a46ef99dSLinus Torvalds int ret; 2748bfce281cSAl Viro struct mm_struct *mm = current->mm; 2749897ab3e0SMike Rapoport LIST_HEAD(uf); 2750183654ceSLiam R. Howlett VMA_ITERATOR(vmi, mm, start); 2751a46ef99dSLinus Torvalds 2752d8ed45c5SMichel Lespinasse if (mmap_write_lock_killable(mm)) 2753ae798783SMichal Hocko return -EINTR; 2754ae798783SMichal Hocko 2755183654ceSLiam R. Howlett ret = do_vmi_munmap(&vmi, mm, start, len, &uf, downgrade); 2756dd2283f2SYang Shi /* 2757c1e8d7c6SMichel Lespinasse * Returning 1 indicates mmap_lock is downgraded. 2758dd2283f2SYang Shi * But 1 is not legal return value of vm_munmap() and munmap(), reset 2759dd2283f2SYang Shi * it to 0 before return. 2760dd2283f2SYang Shi */ 2761dd2283f2SYang Shi if (ret == 1) { 2762d8ed45c5SMichel Lespinasse mmap_read_unlock(mm); 2763dd2283f2SYang Shi ret = 0; 2764dd2283f2SYang Shi } else 2765d8ed45c5SMichel Lespinasse mmap_write_unlock(mm); 2766dd2283f2SYang Shi 2767897ab3e0SMike Rapoport userfaultfd_unmap_complete(mm, &uf); 2768a46ef99dSLinus Torvalds return ret; 2769a46ef99dSLinus Torvalds } 2770dd2283f2SYang Shi 2771dd2283f2SYang Shi int vm_munmap(unsigned long start, size_t len) 2772dd2283f2SYang Shi { 2773dd2283f2SYang Shi return __vm_munmap(start, len, false); 2774dd2283f2SYang Shi } 2775a46ef99dSLinus Torvalds EXPORT_SYMBOL(vm_munmap); 2776a46ef99dSLinus Torvalds 27776a6160a7SHeiko Carstens SYSCALL_DEFINE2(munmap, unsigned long, addr, size_t, len) 27781da177e4SLinus Torvalds { 2779ce18d171SCatalin Marinas addr = untagged_addr(addr); 2780dd2283f2SYang Shi return __vm_munmap(addr, len, true); 27811da177e4SLinus Torvalds } 27821da177e4SLinus Torvalds 2783c8d78c18SKirill A. Shutemov 2784c8d78c18SKirill A. Shutemov /* 2785c8d78c18SKirill A. Shutemov * Emulation of deprecated remap_file_pages() syscall. 2786c8d78c18SKirill A. Shutemov */ 2787c8d78c18SKirill A. Shutemov SYSCALL_DEFINE5(remap_file_pages, unsigned long, start, unsigned long, size, 2788c8d78c18SKirill A. Shutemov unsigned long, prot, unsigned long, pgoff, unsigned long, flags) 2789c8d78c18SKirill A. Shutemov { 2790c8d78c18SKirill A. Shutemov 2791c8d78c18SKirill A. Shutemov struct mm_struct *mm = current->mm; 2792c8d78c18SKirill A. Shutemov struct vm_area_struct *vma; 2793c8d78c18SKirill A. Shutemov unsigned long populate = 0; 2794c8d78c18SKirill A. Shutemov unsigned long ret = -EINVAL; 2795c8d78c18SKirill A. Shutemov struct file *file; 2796c8d78c18SKirill A. Shutemov 2797ee65728eSMike Rapoport pr_warn_once("%s (%d) uses deprecated remap_file_pages() syscall. See Documentation/mm/remap_file_pages.rst.\n", 2798c8d78c18SKirill A. Shutemov current->comm, current->pid); 2799c8d78c18SKirill A. Shutemov 2800c8d78c18SKirill A. Shutemov if (prot) 2801c8d78c18SKirill A. Shutemov return ret; 2802c8d78c18SKirill A. Shutemov start = start & PAGE_MASK; 2803c8d78c18SKirill A. Shutemov size = size & PAGE_MASK; 2804c8d78c18SKirill A. Shutemov 2805c8d78c18SKirill A. Shutemov if (start + size <= start) 2806c8d78c18SKirill A. Shutemov return ret; 2807c8d78c18SKirill A. Shutemov 2808c8d78c18SKirill A. Shutemov /* Does pgoff wrap? */ 2809c8d78c18SKirill A. Shutemov if (pgoff + (size >> PAGE_SHIFT) < pgoff) 2810c8d78c18SKirill A. Shutemov return ret; 2811c8d78c18SKirill A. Shutemov 2812d8ed45c5SMichel Lespinasse if (mmap_write_lock_killable(mm)) 2813dc0ef0dfSMichal Hocko return -EINTR; 2814dc0ef0dfSMichal Hocko 28159b593cb2SLiam R. Howlett vma = vma_lookup(mm, start); 2816c8d78c18SKirill A. Shutemov 2817c8d78c18SKirill A. Shutemov if (!vma || !(vma->vm_flags & VM_SHARED)) 2818c8d78c18SKirill A. Shutemov goto out; 2819c8d78c18SKirill A. Shutemov 282048f7df32SKirill A. Shutemov if (start + size > vma->vm_end) { 2821763ecb03SLiam R. Howlett VMA_ITERATOR(vmi, mm, vma->vm_end); 2822763ecb03SLiam R. Howlett struct vm_area_struct *next, *prev = vma; 282348f7df32SKirill A. Shutemov 2824763ecb03SLiam R. Howlett for_each_vma_range(vmi, next, start + size) { 282548f7df32SKirill A. Shutemov /* hole between vmas ? */ 2826763ecb03SLiam R. Howlett if (next->vm_start != prev->vm_end) 282748f7df32SKirill A. Shutemov goto out; 282848f7df32SKirill A. Shutemov 282948f7df32SKirill A. Shutemov if (next->vm_file != vma->vm_file) 283048f7df32SKirill A. Shutemov goto out; 283148f7df32SKirill A. Shutemov 283248f7df32SKirill A. Shutemov if (next->vm_flags != vma->vm_flags) 283348f7df32SKirill A. Shutemov goto out; 283448f7df32SKirill A. Shutemov 28351db43d3fSLiam Howlett if (start + size <= next->vm_end) 28361db43d3fSLiam Howlett break; 28371db43d3fSLiam Howlett 2838763ecb03SLiam R. Howlett prev = next; 283948f7df32SKirill A. Shutemov } 284048f7df32SKirill A. Shutemov 284148f7df32SKirill A. Shutemov if (!next) 2842c8d78c18SKirill A. Shutemov goto out; 2843c8d78c18SKirill A. Shutemov } 2844c8d78c18SKirill A. Shutemov 2845c8d78c18SKirill A. Shutemov prot |= vma->vm_flags & VM_READ ? PROT_READ : 0; 2846c8d78c18SKirill A. Shutemov prot |= vma->vm_flags & VM_WRITE ? PROT_WRITE : 0; 2847c8d78c18SKirill A. Shutemov prot |= vma->vm_flags & VM_EXEC ? PROT_EXEC : 0; 2848c8d78c18SKirill A. Shutemov 2849c8d78c18SKirill A. Shutemov flags &= MAP_NONBLOCK; 2850c8d78c18SKirill A. Shutemov flags |= MAP_SHARED | MAP_FIXED | MAP_POPULATE; 2851fce000b1SLiam Howlett if (vma->vm_flags & VM_LOCKED) 2852c8d78c18SKirill A. Shutemov flags |= MAP_LOCKED; 285348f7df32SKirill A. Shutemov 2854c8d78c18SKirill A. Shutemov file = get_file(vma->vm_file); 285545e55300SPeter Collingbourne ret = do_mmap(vma->vm_file, start, size, 2856897ab3e0SMike Rapoport prot, flags, pgoff, &populate, NULL); 2857c8d78c18SKirill A. Shutemov fput(file); 2858c8d78c18SKirill A. Shutemov out: 2859d8ed45c5SMichel Lespinasse mmap_write_unlock(mm); 2860c8d78c18SKirill A. Shutemov if (populate) 2861c8d78c18SKirill A. Shutemov mm_populate(ret, populate); 2862c8d78c18SKirill A. Shutemov if (!IS_ERR_VALUE(ret)) 2863c8d78c18SKirill A. Shutemov ret = 0; 2864c8d78c18SKirill A. Shutemov return ret; 2865c8d78c18SKirill A. Shutemov } 2866c8d78c18SKirill A. Shutemov 28671da177e4SLinus Torvalds /* 286827b26701SLiam R. Howlett * do_vma_munmap() - Unmap a full or partial vma. 286927b26701SLiam R. Howlett * @vmi: The vma iterator pointing at the vma 287027b26701SLiam R. Howlett * @vma: The first vma to be munmapped 287127b26701SLiam R. Howlett * @start: the start of the address to unmap 287227b26701SLiam R. Howlett * @end: The end of the address to unmap 28732e7ce7d3SLiam R. Howlett * @uf: The userfaultfd list_head 287427b26701SLiam R. Howlett * @downgrade: Attempt to downgrade or not 28752e7ce7d3SLiam R. Howlett * 287627b26701SLiam R. Howlett * Returns: 0 on success and not downgraded, 1 on success and downgraded. 287727b26701SLiam R. Howlett * unmaps a VMA mapping when the vma iterator is already in position. 287827b26701SLiam R. Howlett * Does not handle alignment. 28791da177e4SLinus Torvalds */ 288027b26701SLiam R. Howlett int do_vma_munmap(struct vma_iterator *vmi, struct vm_area_struct *vma, 288127b26701SLiam R. Howlett unsigned long start, unsigned long end, 288227b26701SLiam R. Howlett struct list_head *uf, bool downgrade) 28832e7ce7d3SLiam R. Howlett { 28842e7ce7d3SLiam R. Howlett struct mm_struct *mm = vma->vm_mm; 28852e7ce7d3SLiam R. Howlett int ret; 28862e7ce7d3SLiam R. Howlett 288727b26701SLiam R. Howlett arch_unmap(mm, start, end); 288827b26701SLiam R. Howlett ret = do_vmi_align_munmap(vmi, vma, mm, start, end, uf, downgrade); 28892e7ce7d3SLiam R. Howlett validate_mm_mt(mm); 28902e7ce7d3SLiam R. Howlett return ret; 28912e7ce7d3SLiam R. Howlett } 28922e7ce7d3SLiam R. Howlett 28932e7ce7d3SLiam R. Howlett /* 28942e7ce7d3SLiam R. Howlett * do_brk_flags() - Increase the brk vma if the flags match. 289592fed820SLiam R. Howlett * @vmi: The vma iterator 28962e7ce7d3SLiam R. Howlett * @addr: The start address 28972e7ce7d3SLiam R. Howlett * @len: The length of the increase 28982e7ce7d3SLiam R. Howlett * @vma: The vma, 28992e7ce7d3SLiam R. Howlett * @flags: The VMA Flags 29002e7ce7d3SLiam R. Howlett * 29012e7ce7d3SLiam R. Howlett * Extend the brk VMA from addr to addr + len. If the VMA is NULL or the flags 29022e7ce7d3SLiam R. Howlett * do not match then create a new anonymous VMA. Eventually we may be able to 29032e7ce7d3SLiam R. Howlett * do some brk-specific accounting here. 29042e7ce7d3SLiam R. Howlett */ 290592fed820SLiam R. Howlett static int do_brk_flags(struct vma_iterator *vmi, struct vm_area_struct *vma, 2906763ecb03SLiam R. Howlett unsigned long addr, unsigned long len, unsigned long flags) 29071da177e4SLinus Torvalds { 29081da177e4SLinus Torvalds struct mm_struct *mm = current->mm; 29092e7ce7d3SLiam R. Howlett 2910d4af56c5SLiam R. Howlett validate_mm_mt(mm); 29112e7ce7d3SLiam R. Howlett /* 29122e7ce7d3SLiam R. Howlett * Check against address space limits by the changed size 29132e7ce7d3SLiam R. Howlett * Note: This happens *after* clearing old mappings in some code paths. 29142e7ce7d3SLiam R. Howlett */ 291516e72e9bSDenys Vlasenko flags |= VM_DATA_DEFAULT_FLAGS | VM_ACCOUNT | mm->def_flags; 291684638335SKonstantin Khlebnikov if (!may_expand_vm(mm, flags, len >> PAGE_SHIFT)) 29171da177e4SLinus Torvalds return -ENOMEM; 29181da177e4SLinus Torvalds 29191da177e4SLinus Torvalds if (mm->map_count > sysctl_max_map_count) 29201da177e4SLinus Torvalds return -ENOMEM; 29211da177e4SLinus Torvalds 2922191c5424SAl Viro if (security_vm_enough_memory_mm(mm, len >> PAGE_SHIFT)) 29231da177e4SLinus Torvalds return -ENOMEM; 29241da177e4SLinus Torvalds 29251da177e4SLinus Torvalds /* 29262e7ce7d3SLiam R. Howlett * Expand the existing vma if possible; Note that singular lists do not 29272e7ce7d3SLiam R. Howlett * occur after forking, so the expand will only happen on new VMAs. 29281da177e4SLinus Torvalds */ 29296c28ca64SLiam Howlett if (vma && vma->vm_end == addr && !vma_policy(vma) && 29306c28ca64SLiam Howlett can_vma_merge_after(vma, flags, NULL, NULL, 29316c28ca64SLiam Howlett addr >> PAGE_SHIFT, NULL_VM_UFFD_CTX, NULL)) { 293292fed820SLiam R. Howlett if (vma_iter_prealloc(vmi)) 2933675eaca1SAlistair Popple goto unacct_fail; 293428c5609fSLiam Howlett 293528c5609fSLiam Howlett vma_adjust_trans_huge(vma, vma->vm_start, addr + len, 0); 29362e7ce7d3SLiam R. Howlett if (vma->anon_vma) { 29372e7ce7d3SLiam R. Howlett anon_vma_lock_write(vma->anon_vma); 29382e7ce7d3SLiam R. Howlett anon_vma_interval_tree_pre_update_vma(vma); 29391da177e4SLinus Torvalds } 29402e7ce7d3SLiam R. Howlett vma->vm_end = addr + len; 29412e7ce7d3SLiam R. Howlett vma->vm_flags |= VM_SOFTDIRTY; 294292fed820SLiam R. Howlett vma_iter_store(vmi, vma); 29432e7ce7d3SLiam R. Howlett 29442e7ce7d3SLiam R. Howlett if (vma->anon_vma) { 29452e7ce7d3SLiam R. Howlett anon_vma_interval_tree_post_update_vma(vma); 29462e7ce7d3SLiam R. Howlett anon_vma_unlock_write(vma->anon_vma); 29472e7ce7d3SLiam R. Howlett } 29482e7ce7d3SLiam R. Howlett khugepaged_enter_vma(vma, flags); 29492e7ce7d3SLiam R. Howlett goto out; 29502e7ce7d3SLiam R. Howlett } 29512e7ce7d3SLiam R. Howlett 29522e7ce7d3SLiam R. Howlett /* create a vma struct for an anonymous mapping */ 29532e7ce7d3SLiam R. Howlett vma = vm_area_alloc(mm); 29542e7ce7d3SLiam R. Howlett if (!vma) 2955675eaca1SAlistair Popple goto unacct_fail; 29561da177e4SLinus Torvalds 2957bfd40eafSKirill A. Shutemov vma_set_anonymous(vma); 29581da177e4SLinus Torvalds vma->vm_start = addr; 29591da177e4SLinus Torvalds vma->vm_end = addr + len; 29602e7ce7d3SLiam R. Howlett vma->vm_pgoff = addr >> PAGE_SHIFT; 29611da177e4SLinus Torvalds vma->vm_flags = flags; 29623ed75eb8SColy Li vma->vm_page_prot = vm_get_page_prot(flags); 296392fed820SLiam R. Howlett if (vma_iter_store_gfp(vmi, vma, GFP_KERNEL)) 29642e7ce7d3SLiam R. Howlett goto mas_store_fail; 2965d4af56c5SLiam R. Howlett 29662e7ce7d3SLiam R. Howlett mm->map_count++; 29671da177e4SLinus Torvalds out: 29683af9e859SEric B Munson perf_event_mmap(vma); 29691da177e4SLinus Torvalds mm->total_vm += len >> PAGE_SHIFT; 297084638335SKonstantin Khlebnikov mm->data_vm += len >> PAGE_SHIFT; 2971128557ffSMichel Lespinasse if (flags & VM_LOCKED) 2972ba470de4SRik van Riel mm->locked_vm += (len >> PAGE_SHIFT); 2973d9104d1cSCyrill Gorcunov vma->vm_flags |= VM_SOFTDIRTY; 2974763ecb03SLiam R. Howlett validate_mm(mm); 29755d22fc25SLinus Torvalds return 0; 2976d4af56c5SLiam R. Howlett 29772e7ce7d3SLiam R. Howlett mas_store_fail: 2978d4af56c5SLiam R. Howlett vm_area_free(vma); 2979675eaca1SAlistair Popple unacct_fail: 29802e7ce7d3SLiam R. Howlett vm_unacct_memory(len >> PAGE_SHIFT); 29812e7ce7d3SLiam R. Howlett return -ENOMEM; 29821da177e4SLinus Torvalds } 29831da177e4SLinus Torvalds 2984bb177a73SMichal Hocko int vm_brk_flags(unsigned long addr, unsigned long request, unsigned long flags) 2985e4eb1ff6SLinus Torvalds { 2986e4eb1ff6SLinus Torvalds struct mm_struct *mm = current->mm; 29872e7ce7d3SLiam R. Howlett struct vm_area_struct *vma = NULL; 2988bb177a73SMichal Hocko unsigned long len; 29895d22fc25SLinus Torvalds int ret; 2990128557ffSMichel Lespinasse bool populate; 2991897ab3e0SMike Rapoport LIST_HEAD(uf); 299292fed820SLiam R. Howlett VMA_ITERATOR(vmi, mm, addr); 2993e4eb1ff6SLinus Torvalds 2994bb177a73SMichal Hocko len = PAGE_ALIGN(request); 2995bb177a73SMichal Hocko if (len < request) 2996bb177a73SMichal Hocko return -ENOMEM; 2997bb177a73SMichal Hocko if (!len) 2998bb177a73SMichal Hocko return 0; 2999bb177a73SMichal Hocko 3000d8ed45c5SMichel Lespinasse if (mmap_write_lock_killable(mm)) 30012d6c9282SMichal Hocko return -EINTR; 30022d6c9282SMichal Hocko 30032e7ce7d3SLiam R. Howlett /* Until we need other flags, refuse anything except VM_EXEC. */ 30042e7ce7d3SLiam R. Howlett if ((flags & (~VM_EXEC)) != 0) 30052e7ce7d3SLiam R. Howlett return -EINVAL; 30062e7ce7d3SLiam R. Howlett 30072e7ce7d3SLiam R. Howlett ret = check_brk_limits(addr, len); 30082e7ce7d3SLiam R. Howlett if (ret) 30092e7ce7d3SLiam R. Howlett goto limits_failed; 30102e7ce7d3SLiam R. Howlett 3011183654ceSLiam R. Howlett ret = do_vmi_munmap(&vmi, mm, addr, len, &uf, 0); 30122e7ce7d3SLiam R. Howlett if (ret) 30132e7ce7d3SLiam R. Howlett goto munmap_failed; 30142e7ce7d3SLiam R. Howlett 301592fed820SLiam R. Howlett vma = vma_prev(&vmi); 301692fed820SLiam R. Howlett ret = do_brk_flags(&vmi, vma, addr, len, flags); 3017128557ffSMichel Lespinasse populate = ((mm->def_flags & VM_LOCKED) != 0); 3018d8ed45c5SMichel Lespinasse mmap_write_unlock(mm); 3019897ab3e0SMike Rapoport userfaultfd_unmap_complete(mm, &uf); 30205d22fc25SLinus Torvalds if (populate && !ret) 3021128557ffSMichel Lespinasse mm_populate(addr, len); 3022e4eb1ff6SLinus Torvalds return ret; 30232e7ce7d3SLiam R. Howlett 30242e7ce7d3SLiam R. Howlett munmap_failed: 30252e7ce7d3SLiam R. Howlett limits_failed: 30262e7ce7d3SLiam R. Howlett mmap_write_unlock(mm); 30272e7ce7d3SLiam R. Howlett return ret; 3028e4eb1ff6SLinus Torvalds } 302916e72e9bSDenys Vlasenko EXPORT_SYMBOL(vm_brk_flags); 303016e72e9bSDenys Vlasenko 303116e72e9bSDenys Vlasenko int vm_brk(unsigned long addr, unsigned long len) 303216e72e9bSDenys Vlasenko { 303316e72e9bSDenys Vlasenko return vm_brk_flags(addr, len, 0); 303416e72e9bSDenys Vlasenko } 3035e4eb1ff6SLinus Torvalds EXPORT_SYMBOL(vm_brk); 30361da177e4SLinus Torvalds 30371da177e4SLinus Torvalds /* Release all mmaps. */ 30381da177e4SLinus Torvalds void exit_mmap(struct mm_struct *mm) 30391da177e4SLinus Torvalds { 3040d16dfc55SPeter Zijlstra struct mmu_gather tlb; 3041ba470de4SRik van Riel struct vm_area_struct *vma; 30421da177e4SLinus Torvalds unsigned long nr_accounted = 0; 3043763ecb03SLiam R. Howlett MA_STATE(mas, &mm->mm_mt, 0, 0); 3044763ecb03SLiam R. Howlett int count = 0; 30451da177e4SLinus Torvalds 3046d6dd61c8SJeremy Fitzhardinge /* mm's last user has gone, and its about to be pulled down */ 3047cddb8a5cSAndrea Arcangeli mmu_notifier_release(mm); 3048d6dd61c8SJeremy Fitzhardinge 3049bf3980c8SSuren Baghdasaryan mmap_read_lock(mm); 30509480c53eSJeremy Fitzhardinge arch_exit_mmap(mm); 30519480c53eSJeremy Fitzhardinge 3052763ecb03SLiam R. Howlett vma = mas_find(&mas, ULONG_MAX); 305364591e86SSuren Baghdasaryan if (!vma) { 305464591e86SSuren Baghdasaryan /* Can happen if dup_mmap() received an OOM */ 3055bf3980c8SSuren Baghdasaryan mmap_read_unlock(mm); 30569480c53eSJeremy Fitzhardinge return; 305764591e86SSuren Baghdasaryan } 30589480c53eSJeremy Fitzhardinge 30591da177e4SLinus Torvalds lru_add_drain(); 30601da177e4SLinus Torvalds flush_cache_mm(mm); 3061d8b45053SWill Deacon tlb_gather_mmu_fullmm(&tlb, mm); 3062901608d9SOleg Nesterov /* update_hiwater_rss(mm) here? but nobody should be looking */ 3063763ecb03SLiam R. Howlett /* Use ULONG_MAX here to ensure all VMAs in the mm are unmapped */ 3064763ecb03SLiam R. Howlett unmap_vmas(&tlb, &mm->mm_mt, vma, 0, ULONG_MAX); 3065bf3980c8SSuren Baghdasaryan mmap_read_unlock(mm); 3066bf3980c8SSuren Baghdasaryan 3067bf3980c8SSuren Baghdasaryan /* 3068bf3980c8SSuren Baghdasaryan * Set MMF_OOM_SKIP to hide this task from the oom killer/reaper 3069b3541d91SSuren Baghdasaryan * because the memory has been already freed. 3070bf3980c8SSuren Baghdasaryan */ 3071bf3980c8SSuren Baghdasaryan set_bit(MMF_OOM_SKIP, &mm->flags); 3072bf3980c8SSuren Baghdasaryan mmap_write_lock(mm); 3073763ecb03SLiam R. Howlett free_pgtables(&tlb, &mm->mm_mt, vma, FIRST_USER_ADDRESS, 3074763ecb03SLiam R. Howlett USER_PGTABLES_CEILING); 3075ae8eba8bSWill Deacon tlb_finish_mmu(&tlb); 30761da177e4SLinus Torvalds 3077763ecb03SLiam R. Howlett /* 3078763ecb03SLiam R. Howlett * Walk the list again, actually closing and freeing it, with preemption 3079763ecb03SLiam R. Howlett * enabled, without holding any MM locks besides the unreachable 3080763ecb03SLiam R. Howlett * mmap_write_lock. 3081763ecb03SLiam R. Howlett */ 3082763ecb03SLiam R. Howlett do { 30834f74d2c8SLinus Torvalds if (vma->vm_flags & VM_ACCOUNT) 30844f74d2c8SLinus Torvalds nr_accounted += vma_pages(vma); 3085763ecb03SLiam R. Howlett remove_vma(vma); 3086763ecb03SLiam R. Howlett count++; 30870a3b3c25SPaul E. McKenney cond_resched(); 3088763ecb03SLiam R. Howlett } while ((vma = mas_find(&mas, ULONG_MAX)) != NULL); 3089763ecb03SLiam R. Howlett 3090763ecb03SLiam R. Howlett BUG_ON(count != mm->map_count); 3091d4af56c5SLiam R. Howlett 3092d4af56c5SLiam R. Howlett trace_exit_mmap(mm); 3093d4af56c5SLiam R. Howlett __mt_destroy(&mm->mm_mt); 309464591e86SSuren Baghdasaryan mmap_write_unlock(mm); 30954f74d2c8SLinus Torvalds vm_unacct_memory(nr_accounted); 30961da177e4SLinus Torvalds } 30971da177e4SLinus Torvalds 30981da177e4SLinus Torvalds /* Insert vm structure into process list sorted by address 30991da177e4SLinus Torvalds * and into the inode's i_mmap tree. If vm_file is non-NULL 3100c8c06efaSDavidlohr Bueso * then i_mmap_rwsem is taken here. 31011da177e4SLinus Torvalds */ 31021da177e4SLinus Torvalds int insert_vm_struct(struct mm_struct *mm, struct vm_area_struct *vma) 31031da177e4SLinus Torvalds { 3104d4af56c5SLiam R. Howlett unsigned long charged = vma_pages(vma); 31051da177e4SLinus Torvalds 3106d4af56c5SLiam R. Howlett 3107d0601a50SLiam R. Howlett if (find_vma_intersection(mm, vma->vm_start, vma->vm_end)) 3108c9d13f5fSChen Gang return -ENOMEM; 3109d4af56c5SLiam R. Howlett 3110c9d13f5fSChen Gang if ((vma->vm_flags & VM_ACCOUNT) && 3111d4af56c5SLiam R. Howlett security_vm_enough_memory_mm(mm, charged)) 3112c9d13f5fSChen Gang return -ENOMEM; 3113c9d13f5fSChen Gang 31141da177e4SLinus Torvalds /* 31151da177e4SLinus Torvalds * The vm_pgoff of a purely anonymous vma should be irrelevant 31161da177e4SLinus Torvalds * until its first write fault, when page's anon_vma and index 31171da177e4SLinus Torvalds * are set. But now set the vm_pgoff it will almost certainly 31181da177e4SLinus Torvalds * end up with (unless mremap moves it elsewhere before that 31191da177e4SLinus Torvalds * first wfault), so /proc/pid/maps tells a consistent story. 31201da177e4SLinus Torvalds * 31211da177e4SLinus Torvalds * By setting it to reflect the virtual start address of the 31221da177e4SLinus Torvalds * vma, merges and splits can happen in a seamless way, just 31231da177e4SLinus Torvalds * using the existing file pgoff checks and manipulations. 31248332326eSLiao Pingfang * Similarly in do_mmap and in do_brk_flags. 31251da177e4SLinus Torvalds */ 31268a9cc3b5SOleg Nesterov if (vma_is_anonymous(vma)) { 31271da177e4SLinus Torvalds BUG_ON(vma->anon_vma); 31281da177e4SLinus Torvalds vma->vm_pgoff = vma->vm_start >> PAGE_SHIFT; 31291da177e4SLinus Torvalds } 31302b144498SSrikar Dronamraju 3131763ecb03SLiam R. Howlett if (vma_link(mm, vma)) { 3132d4af56c5SLiam R. Howlett vm_unacct_memory(charged); 3133d4af56c5SLiam R. Howlett return -ENOMEM; 3134d4af56c5SLiam R. Howlett } 3135d4af56c5SLiam R. Howlett 31361da177e4SLinus Torvalds return 0; 31371da177e4SLinus Torvalds } 31381da177e4SLinus Torvalds 31391da177e4SLinus Torvalds /* 31401da177e4SLinus Torvalds * Copy the vma structure to a new location in the same mm, 31411da177e4SLinus Torvalds * prior to moving page table entries, to effect an mremap move. 31421da177e4SLinus Torvalds */ 31431da177e4SLinus Torvalds struct vm_area_struct *copy_vma(struct vm_area_struct **vmap, 314438a76013SMichel Lespinasse unsigned long addr, unsigned long len, pgoff_t pgoff, 314538a76013SMichel Lespinasse bool *need_rmap_locks) 31461da177e4SLinus Torvalds { 31471da177e4SLinus Torvalds struct vm_area_struct *vma = *vmap; 31481da177e4SLinus Torvalds unsigned long vma_start = vma->vm_start; 31491da177e4SLinus Torvalds struct mm_struct *mm = vma->vm_mm; 31501da177e4SLinus Torvalds struct vm_area_struct *new_vma, *prev; 3151948f017bSAndrea Arcangeli bool faulted_in_anon_vma = true; 3152076f16bfSLiam R. Howlett VMA_ITERATOR(vmi, mm, addr); 31531da177e4SLinus Torvalds 3154d4af56c5SLiam R. Howlett validate_mm_mt(mm); 31551da177e4SLinus Torvalds /* 31561da177e4SLinus Torvalds * If anonymous vma has not yet been faulted, update new pgoff 31571da177e4SLinus Torvalds * to match new location, to increase its chance of merging. 31581da177e4SLinus Torvalds */ 3159ce75799bSOleg Nesterov if (unlikely(vma_is_anonymous(vma) && !vma->anon_vma)) { 31601da177e4SLinus Torvalds pgoff = addr >> PAGE_SHIFT; 3161948f017bSAndrea Arcangeli faulted_in_anon_vma = false; 3162948f017bSAndrea Arcangeli } 31631da177e4SLinus Torvalds 3164763ecb03SLiam R. Howlett new_vma = find_vma_prev(mm, addr, &prev); 3165763ecb03SLiam R. Howlett if (new_vma && new_vma->vm_start < addr + len) 31666597d783SHugh Dickins return NULL; /* should never get here */ 3167524e00b3SLiam R. Howlett 31689760ebffSLiam R. Howlett new_vma = vma_merge(&vmi, mm, prev, addr, addr + len, vma->vm_flags, 316919a809afSAndrea Arcangeli vma->anon_vma, vma->vm_file, pgoff, vma_policy(vma), 31705c26f6acSSuren Baghdasaryan vma->vm_userfaultfd_ctx, anon_vma_name(vma)); 31711da177e4SLinus Torvalds if (new_vma) { 31721da177e4SLinus Torvalds /* 31731da177e4SLinus Torvalds * Source vma may have been merged into new_vma 31741da177e4SLinus Torvalds */ 3175948f017bSAndrea Arcangeli if (unlikely(vma_start >= new_vma->vm_start && 3176948f017bSAndrea Arcangeli vma_start < new_vma->vm_end)) { 3177948f017bSAndrea Arcangeli /* 3178948f017bSAndrea Arcangeli * The only way we can get a vma_merge with 3179948f017bSAndrea Arcangeli * self during an mremap is if the vma hasn't 3180948f017bSAndrea Arcangeli * been faulted in yet and we were allowed to 3181948f017bSAndrea Arcangeli * reset the dst vma->vm_pgoff to the 3182948f017bSAndrea Arcangeli * destination address of the mremap to allow 3183948f017bSAndrea Arcangeli * the merge to happen. mremap must change the 3184948f017bSAndrea Arcangeli * vm_pgoff linearity between src and dst vmas 3185948f017bSAndrea Arcangeli * (in turn preventing a vma_merge) to be 3186948f017bSAndrea Arcangeli * safe. It is only safe to keep the vm_pgoff 3187948f017bSAndrea Arcangeli * linear if there are no pages mapped yet. 3188948f017bSAndrea Arcangeli */ 318981d1b09cSSasha Levin VM_BUG_ON_VMA(faulted_in_anon_vma, new_vma); 319038a76013SMichel Lespinasse *vmap = vma = new_vma; 3191108d6642SMichel Lespinasse } 319238a76013SMichel Lespinasse *need_rmap_locks = (new_vma->vm_pgoff <= vma->vm_pgoff); 31931da177e4SLinus Torvalds } else { 31943928d4f5SLinus Torvalds new_vma = vm_area_dup(vma); 3195e3975891SChen Gang if (!new_vma) 3196e3975891SChen Gang goto out; 31971da177e4SLinus Torvalds new_vma->vm_start = addr; 31981da177e4SLinus Torvalds new_vma->vm_end = addr + len; 31991da177e4SLinus Torvalds new_vma->vm_pgoff = pgoff; 3200ef0855d3SOleg Nesterov if (vma_dup_policy(vma, new_vma)) 3201523d4e20SMichel Lespinasse goto out_free_vma; 3202523d4e20SMichel Lespinasse if (anon_vma_clone(new_vma, vma)) 3203523d4e20SMichel Lespinasse goto out_free_mempol; 3204e9714acfSKonstantin Khlebnikov if (new_vma->vm_file) 32051da177e4SLinus Torvalds get_file(new_vma->vm_file); 32061da177e4SLinus Torvalds if (new_vma->vm_ops && new_vma->vm_ops->open) 32071da177e4SLinus Torvalds new_vma->vm_ops->open(new_vma); 3208763ecb03SLiam R. Howlett if (vma_link(mm, new_vma)) 3209524e00b3SLiam R. Howlett goto out_vma_link; 321038a76013SMichel Lespinasse *need_rmap_locks = false; 32111da177e4SLinus Torvalds } 3212d4af56c5SLiam R. Howlett validate_mm_mt(mm); 32131da177e4SLinus Torvalds return new_vma; 32145beb4930SRik van Riel 3215524e00b3SLiam R. Howlett out_vma_link: 3216524e00b3SLiam R. Howlett if (new_vma->vm_ops && new_vma->vm_ops->close) 3217524e00b3SLiam R. Howlett new_vma->vm_ops->close(new_vma); 321892b73996SLiam Howlett 321992b73996SLiam Howlett if (new_vma->vm_file) 322092b73996SLiam Howlett fput(new_vma->vm_file); 322192b73996SLiam Howlett 322292b73996SLiam Howlett unlink_anon_vmas(new_vma); 32235beb4930SRik van Riel out_free_mempol: 3224ef0855d3SOleg Nesterov mpol_put(vma_policy(new_vma)); 32255beb4930SRik van Riel out_free_vma: 32263928d4f5SLinus Torvalds vm_area_free(new_vma); 3227e3975891SChen Gang out: 3228d4af56c5SLiam R. Howlett validate_mm_mt(mm); 32295beb4930SRik van Riel return NULL; 32301da177e4SLinus Torvalds } 3231119f657cSakpm@osdl.org 3232119f657cSakpm@osdl.org /* 3233119f657cSakpm@osdl.org * Return true if the calling process may expand its vm space by the passed 3234119f657cSakpm@osdl.org * number of pages 3235119f657cSakpm@osdl.org */ 323684638335SKonstantin Khlebnikov bool may_expand_vm(struct mm_struct *mm, vm_flags_t flags, unsigned long npages) 3237119f657cSakpm@osdl.org { 323884638335SKonstantin Khlebnikov if (mm->total_vm + npages > rlimit(RLIMIT_AS) >> PAGE_SHIFT) 323984638335SKonstantin Khlebnikov return false; 3240119f657cSakpm@osdl.org 3241d977d56cSKonstantin Khlebnikov if (is_data_mapping(flags) && 3242d977d56cSKonstantin Khlebnikov mm->data_vm + npages > rlimit(RLIMIT_DATA) >> PAGE_SHIFT) { 3243f4fcd558SKonstantin Khlebnikov /* Workaround for Valgrind */ 3244f4fcd558SKonstantin Khlebnikov if (rlimit(RLIMIT_DATA) == 0 && 3245f4fcd558SKonstantin Khlebnikov mm->data_vm + npages <= rlimit_max(RLIMIT_DATA) >> PAGE_SHIFT) 3246f4fcd558SKonstantin Khlebnikov return true; 324757a7702bSDavid Woodhouse 324857a7702bSDavid Woodhouse pr_warn_once("%s (%d): VmData %lu exceed data ulimit %lu. Update limits%s.\n", 3249d977d56cSKonstantin Khlebnikov current->comm, current->pid, 3250d977d56cSKonstantin Khlebnikov (mm->data_vm + npages) << PAGE_SHIFT, 325157a7702bSDavid Woodhouse rlimit(RLIMIT_DATA), 325257a7702bSDavid Woodhouse ignore_rlimit_data ? "" : " or use boot option ignore_rlimit_data"); 325357a7702bSDavid Woodhouse 325457a7702bSDavid Woodhouse if (!ignore_rlimit_data) 3255d977d56cSKonstantin Khlebnikov return false; 3256d977d56cSKonstantin Khlebnikov } 3257119f657cSakpm@osdl.org 325884638335SKonstantin Khlebnikov return true; 325984638335SKonstantin Khlebnikov } 326084638335SKonstantin Khlebnikov 326184638335SKonstantin Khlebnikov void vm_stat_account(struct mm_struct *mm, vm_flags_t flags, long npages) 326284638335SKonstantin Khlebnikov { 32637866076bSPeng Liu WRITE_ONCE(mm->total_vm, READ_ONCE(mm->total_vm)+npages); 326484638335SKonstantin Khlebnikov 3265d977d56cSKonstantin Khlebnikov if (is_exec_mapping(flags)) 326684638335SKonstantin Khlebnikov mm->exec_vm += npages; 3267d977d56cSKonstantin Khlebnikov else if (is_stack_mapping(flags)) 326884638335SKonstantin Khlebnikov mm->stack_vm += npages; 3269d977d56cSKonstantin Khlebnikov else if (is_data_mapping(flags)) 327084638335SKonstantin Khlebnikov mm->data_vm += npages; 3271119f657cSakpm@osdl.org } 3272fa5dc22fSRoland McGrath 3273b3ec9f33SSouptick Joarder static vm_fault_t special_mapping_fault(struct vm_fault *vmf); 3274a62c34bdSAndy Lutomirski 3275a62c34bdSAndy Lutomirski /* 3276a62c34bdSAndy Lutomirski * Having a close hook prevents vma merging regardless of flags. 3277a62c34bdSAndy Lutomirski */ 3278a62c34bdSAndy Lutomirski static void special_mapping_close(struct vm_area_struct *vma) 3279a62c34bdSAndy Lutomirski { 3280a62c34bdSAndy Lutomirski } 3281a62c34bdSAndy Lutomirski 3282a62c34bdSAndy Lutomirski static const char *special_mapping_name(struct vm_area_struct *vma) 3283a62c34bdSAndy Lutomirski { 3284a62c34bdSAndy Lutomirski return ((struct vm_special_mapping *)vma->vm_private_data)->name; 3285a62c34bdSAndy Lutomirski } 3286a62c34bdSAndy Lutomirski 328714d07113SBrian Geffon static int special_mapping_mremap(struct vm_area_struct *new_vma) 3288b059a453SDmitry Safonov { 3289b059a453SDmitry Safonov struct vm_special_mapping *sm = new_vma->vm_private_data; 3290b059a453SDmitry Safonov 3291280e87e9SDmitry Safonov if (WARN_ON_ONCE(current->mm != new_vma->vm_mm)) 3292280e87e9SDmitry Safonov return -EFAULT; 3293280e87e9SDmitry Safonov 3294b059a453SDmitry Safonov if (sm->mremap) 3295b059a453SDmitry Safonov return sm->mremap(sm, new_vma); 3296280e87e9SDmitry Safonov 3297b059a453SDmitry Safonov return 0; 3298b059a453SDmitry Safonov } 3299b059a453SDmitry Safonov 3300871402e0SDmitry Safonov static int special_mapping_split(struct vm_area_struct *vma, unsigned long addr) 3301871402e0SDmitry Safonov { 3302871402e0SDmitry Safonov /* 3303871402e0SDmitry Safonov * Forbid splitting special mappings - kernel has expectations over 3304871402e0SDmitry Safonov * the number of pages in mapping. Together with VM_DONTEXPAND 3305871402e0SDmitry Safonov * the size of vma should stay the same over the special mapping's 3306871402e0SDmitry Safonov * lifetime. 3307871402e0SDmitry Safonov */ 3308871402e0SDmitry Safonov return -EINVAL; 3309871402e0SDmitry Safonov } 3310871402e0SDmitry Safonov 3311a62c34bdSAndy Lutomirski static const struct vm_operations_struct special_mapping_vmops = { 3312a62c34bdSAndy Lutomirski .close = special_mapping_close, 3313a62c34bdSAndy Lutomirski .fault = special_mapping_fault, 3314b059a453SDmitry Safonov .mremap = special_mapping_mremap, 3315a62c34bdSAndy Lutomirski .name = special_mapping_name, 3316af34ebebSDmitry Safonov /* vDSO code relies that VVAR can't be accessed remotely */ 3317af34ebebSDmitry Safonov .access = NULL, 3318871402e0SDmitry Safonov .may_split = special_mapping_split, 3319a62c34bdSAndy Lutomirski }; 3320a62c34bdSAndy Lutomirski 3321a62c34bdSAndy Lutomirski static const struct vm_operations_struct legacy_special_mapping_vmops = { 3322a62c34bdSAndy Lutomirski .close = special_mapping_close, 3323a62c34bdSAndy Lutomirski .fault = special_mapping_fault, 3324a62c34bdSAndy Lutomirski }; 3325fa5dc22fSRoland McGrath 3326b3ec9f33SSouptick Joarder static vm_fault_t special_mapping_fault(struct vm_fault *vmf) 3327fa5dc22fSRoland McGrath { 332811bac800SDave Jiang struct vm_area_struct *vma = vmf->vma; 3329b1d0e4f5SNick Piggin pgoff_t pgoff; 3330fa5dc22fSRoland McGrath struct page **pages; 3331fa5dc22fSRoland McGrath 3332f872f540SAndy Lutomirski if (vma->vm_ops == &legacy_special_mapping_vmops) { 3333a62c34bdSAndy Lutomirski pages = vma->vm_private_data; 3334f872f540SAndy Lutomirski } else { 3335f872f540SAndy Lutomirski struct vm_special_mapping *sm = vma->vm_private_data; 3336f872f540SAndy Lutomirski 3337f872f540SAndy Lutomirski if (sm->fault) 333811bac800SDave Jiang return sm->fault(sm, vmf->vma, vmf); 3339f872f540SAndy Lutomirski 3340f872f540SAndy Lutomirski pages = sm->pages; 3341f872f540SAndy Lutomirski } 3342a62c34bdSAndy Lutomirski 33438a9cc3b5SOleg Nesterov for (pgoff = vmf->pgoff; pgoff && *pages; ++pages) 3344b1d0e4f5SNick Piggin pgoff--; 3345fa5dc22fSRoland McGrath 3346fa5dc22fSRoland McGrath if (*pages) { 3347fa5dc22fSRoland McGrath struct page *page = *pages; 3348fa5dc22fSRoland McGrath get_page(page); 3349b1d0e4f5SNick Piggin vmf->page = page; 3350b1d0e4f5SNick Piggin return 0; 3351fa5dc22fSRoland McGrath } 3352fa5dc22fSRoland McGrath 3353b1d0e4f5SNick Piggin return VM_FAULT_SIGBUS; 3354fa5dc22fSRoland McGrath } 3355fa5dc22fSRoland McGrath 3356a62c34bdSAndy Lutomirski static struct vm_area_struct *__install_special_mapping( 3357a62c34bdSAndy Lutomirski struct mm_struct *mm, 3358fa5dc22fSRoland McGrath unsigned long addr, unsigned long len, 335927f28b97SChen Gang unsigned long vm_flags, void *priv, 336027f28b97SChen Gang const struct vm_operations_struct *ops) 3361fa5dc22fSRoland McGrath { 3362462e635eSTavis Ormandy int ret; 3363fa5dc22fSRoland McGrath struct vm_area_struct *vma; 3364fa5dc22fSRoland McGrath 3365d4af56c5SLiam R. Howlett validate_mm_mt(mm); 3366490fc053SLinus Torvalds vma = vm_area_alloc(mm); 3367fa5dc22fSRoland McGrath if (unlikely(vma == NULL)) 33683935ed6aSStefani Seibold return ERR_PTR(-ENOMEM); 3369fa5dc22fSRoland McGrath 3370fa5dc22fSRoland McGrath vma->vm_start = addr; 3371fa5dc22fSRoland McGrath vma->vm_end = addr + len; 3372fa5dc22fSRoland McGrath 3373d9104d1cSCyrill Gorcunov vma->vm_flags = vm_flags | mm->def_flags | VM_DONTEXPAND | VM_SOFTDIRTY; 33741fc09228SHugh Dickins vma->vm_flags &= VM_LOCKED_CLEAR_MASK; 33753ed75eb8SColy Li vma->vm_page_prot = vm_get_page_prot(vma->vm_flags); 3376fa5dc22fSRoland McGrath 3377a62c34bdSAndy Lutomirski vma->vm_ops = ops; 3378a62c34bdSAndy Lutomirski vma->vm_private_data = priv; 3379fa5dc22fSRoland McGrath 3380462e635eSTavis Ormandy ret = insert_vm_struct(mm, vma); 3381462e635eSTavis Ormandy if (ret) 3382462e635eSTavis Ormandy goto out; 3383fa5dc22fSRoland McGrath 338484638335SKonstantin Khlebnikov vm_stat_account(mm, vma->vm_flags, len >> PAGE_SHIFT); 3385fa5dc22fSRoland McGrath 3386cdd6c482SIngo Molnar perf_event_mmap(vma); 3387089dd79dSPeter Zijlstra 3388d4af56c5SLiam R. Howlett validate_mm_mt(mm); 33893935ed6aSStefani Seibold return vma; 3390462e635eSTavis Ormandy 3391462e635eSTavis Ormandy out: 33923928d4f5SLinus Torvalds vm_area_free(vma); 3393d4af56c5SLiam R. Howlett validate_mm_mt(mm); 33943935ed6aSStefani Seibold return ERR_PTR(ret); 33953935ed6aSStefani Seibold } 33963935ed6aSStefani Seibold 33972eefd878SDmitry Safonov bool vma_is_special_mapping(const struct vm_area_struct *vma, 33982eefd878SDmitry Safonov const struct vm_special_mapping *sm) 33992eefd878SDmitry Safonov { 34002eefd878SDmitry Safonov return vma->vm_private_data == sm && 34012eefd878SDmitry Safonov (vma->vm_ops == &special_mapping_vmops || 34022eefd878SDmitry Safonov vma->vm_ops == &legacy_special_mapping_vmops); 34032eefd878SDmitry Safonov } 34042eefd878SDmitry Safonov 3405a62c34bdSAndy Lutomirski /* 3406c1e8d7c6SMichel Lespinasse * Called with mm->mmap_lock held for writing. 3407a62c34bdSAndy Lutomirski * Insert a new vma covering the given region, with the given flags. 3408a62c34bdSAndy Lutomirski * Its pages are supplied by the given array of struct page *. 3409a62c34bdSAndy Lutomirski * The array can be shorter than len >> PAGE_SHIFT if it's null-terminated. 3410a62c34bdSAndy Lutomirski * The region past the last page supplied will always produce SIGBUS. 3411a62c34bdSAndy Lutomirski * The array pointer and the pages it points to are assumed to stay alive 3412a62c34bdSAndy Lutomirski * for as long as this mapping might exist. 3413a62c34bdSAndy Lutomirski */ 3414a62c34bdSAndy Lutomirski struct vm_area_struct *_install_special_mapping( 3415a62c34bdSAndy Lutomirski struct mm_struct *mm, 3416a62c34bdSAndy Lutomirski unsigned long addr, unsigned long len, 3417a62c34bdSAndy Lutomirski unsigned long vm_flags, const struct vm_special_mapping *spec) 3418a62c34bdSAndy Lutomirski { 341927f28b97SChen Gang return __install_special_mapping(mm, addr, len, vm_flags, (void *)spec, 342027f28b97SChen Gang &special_mapping_vmops); 3421a62c34bdSAndy Lutomirski } 3422a62c34bdSAndy Lutomirski 34233935ed6aSStefani Seibold int install_special_mapping(struct mm_struct *mm, 34243935ed6aSStefani Seibold unsigned long addr, unsigned long len, 34253935ed6aSStefani Seibold unsigned long vm_flags, struct page **pages) 34263935ed6aSStefani Seibold { 3427a62c34bdSAndy Lutomirski struct vm_area_struct *vma = __install_special_mapping( 342827f28b97SChen Gang mm, addr, len, vm_flags, (void *)pages, 342927f28b97SChen Gang &legacy_special_mapping_vmops); 34303935ed6aSStefani Seibold 343114bd5b45SDuan Jiong return PTR_ERR_OR_ZERO(vma); 3432fa5dc22fSRoland McGrath } 34337906d00cSAndrea Arcangeli 34347906d00cSAndrea Arcangeli static DEFINE_MUTEX(mm_all_locks_mutex); 34357906d00cSAndrea Arcangeli 3436454ed842SPeter Zijlstra static void vm_lock_anon_vma(struct mm_struct *mm, struct anon_vma *anon_vma) 34377906d00cSAndrea Arcangeli { 3438f808c13fSDavidlohr Bueso if (!test_bit(0, (unsigned long *) &anon_vma->root->rb_root.rb_root.rb_node)) { 34397906d00cSAndrea Arcangeli /* 34407906d00cSAndrea Arcangeli * The LSB of head.next can't change from under us 34417906d00cSAndrea Arcangeli * because we hold the mm_all_locks_mutex. 34427906d00cSAndrea Arcangeli */ 3443da1c55f1SMichel Lespinasse down_write_nest_lock(&anon_vma->root->rwsem, &mm->mmap_lock); 34447906d00cSAndrea Arcangeli /* 34457906d00cSAndrea Arcangeli * We can safely modify head.next after taking the 34465a505085SIngo Molnar * anon_vma->root->rwsem. If some other vma in this mm shares 34477906d00cSAndrea Arcangeli * the same anon_vma we won't take it again. 34487906d00cSAndrea Arcangeli * 34497906d00cSAndrea Arcangeli * No need of atomic instructions here, head.next 34507906d00cSAndrea Arcangeli * can't change from under us thanks to the 34515a505085SIngo Molnar * anon_vma->root->rwsem. 34527906d00cSAndrea Arcangeli */ 34537906d00cSAndrea Arcangeli if (__test_and_set_bit(0, (unsigned long *) 3454f808c13fSDavidlohr Bueso &anon_vma->root->rb_root.rb_root.rb_node)) 34557906d00cSAndrea Arcangeli BUG(); 34567906d00cSAndrea Arcangeli } 34577906d00cSAndrea Arcangeli } 34587906d00cSAndrea Arcangeli 3459454ed842SPeter Zijlstra static void vm_lock_mapping(struct mm_struct *mm, struct address_space *mapping) 34607906d00cSAndrea Arcangeli { 34617906d00cSAndrea Arcangeli if (!test_bit(AS_MM_ALL_LOCKS, &mapping->flags)) { 34627906d00cSAndrea Arcangeli /* 34637906d00cSAndrea Arcangeli * AS_MM_ALL_LOCKS can't change from under us because 34647906d00cSAndrea Arcangeli * we hold the mm_all_locks_mutex. 34657906d00cSAndrea Arcangeli * 34667906d00cSAndrea Arcangeli * Operations on ->flags have to be atomic because 34677906d00cSAndrea Arcangeli * even if AS_MM_ALL_LOCKS is stable thanks to the 34687906d00cSAndrea Arcangeli * mm_all_locks_mutex, there may be other cpus 34697906d00cSAndrea Arcangeli * changing other bitflags in parallel to us. 34707906d00cSAndrea Arcangeli */ 34717906d00cSAndrea Arcangeli if (test_and_set_bit(AS_MM_ALL_LOCKS, &mapping->flags)) 34727906d00cSAndrea Arcangeli BUG(); 3473da1c55f1SMichel Lespinasse down_write_nest_lock(&mapping->i_mmap_rwsem, &mm->mmap_lock); 34747906d00cSAndrea Arcangeli } 34757906d00cSAndrea Arcangeli } 34767906d00cSAndrea Arcangeli 34777906d00cSAndrea Arcangeli /* 34787906d00cSAndrea Arcangeli * This operation locks against the VM for all pte/vma/mm related 34797906d00cSAndrea Arcangeli * operations that could ever happen on a certain mm. This includes 34807906d00cSAndrea Arcangeli * vmtruncate, try_to_unmap, and all page faults. 34817906d00cSAndrea Arcangeli * 3482c1e8d7c6SMichel Lespinasse * The caller must take the mmap_lock in write mode before calling 34837906d00cSAndrea Arcangeli * mm_take_all_locks(). The caller isn't allowed to release the 3484c1e8d7c6SMichel Lespinasse * mmap_lock until mm_drop_all_locks() returns. 34857906d00cSAndrea Arcangeli * 3486c1e8d7c6SMichel Lespinasse * mmap_lock in write mode is required in order to block all operations 34877906d00cSAndrea Arcangeli * that could modify pagetables and free pages without need of 348827ba0644SKirill A. Shutemov * altering the vma layout. It's also needed in write mode to avoid new 34897906d00cSAndrea Arcangeli * anon_vmas to be associated with existing vmas. 34907906d00cSAndrea Arcangeli * 34917906d00cSAndrea Arcangeli * A single task can't take more than one mm_take_all_locks() in a row 34927906d00cSAndrea Arcangeli * or it would deadlock. 34937906d00cSAndrea Arcangeli * 3494bf181b9fSMichel Lespinasse * The LSB in anon_vma->rb_root.rb_node and the AS_MM_ALL_LOCKS bitflag in 34957906d00cSAndrea Arcangeli * mapping->flags avoid to take the same lock twice, if more than one 34967906d00cSAndrea Arcangeli * vma in this mm is backed by the same anon_vma or address_space. 34977906d00cSAndrea Arcangeli * 349888f306b6SKirill A. Shutemov * We take locks in following order, accordingly to comment at beginning 349988f306b6SKirill A. Shutemov * of mm/rmap.c: 350088f306b6SKirill A. Shutemov * - all hugetlbfs_i_mmap_rwsem_key locks (aka mapping->i_mmap_rwsem for 350188f306b6SKirill A. Shutemov * hugetlb mapping); 350288f306b6SKirill A. Shutemov * - all i_mmap_rwsem locks; 350388f306b6SKirill A. Shutemov * - all anon_vma->rwseml 350488f306b6SKirill A. Shutemov * 350588f306b6SKirill A. Shutemov * We can take all locks within these types randomly because the VM code 350688f306b6SKirill A. Shutemov * doesn't nest them and we protected from parallel mm_take_all_locks() by 350788f306b6SKirill A. Shutemov * mm_all_locks_mutex. 35087906d00cSAndrea Arcangeli * 35097906d00cSAndrea Arcangeli * mm_take_all_locks() and mm_drop_all_locks are expensive operations 35107906d00cSAndrea Arcangeli * that may have to take thousand of locks. 35117906d00cSAndrea Arcangeli * 35127906d00cSAndrea Arcangeli * mm_take_all_locks() can fail if it's interrupted by signals. 35137906d00cSAndrea Arcangeli */ 35147906d00cSAndrea Arcangeli int mm_take_all_locks(struct mm_struct *mm) 35157906d00cSAndrea Arcangeli { 35167906d00cSAndrea Arcangeli struct vm_area_struct *vma; 35175beb4930SRik van Riel struct anon_vma_chain *avc; 3518763ecb03SLiam R. Howlett MA_STATE(mas, &mm->mm_mt, 0, 0); 35197906d00cSAndrea Arcangeli 3520325bca1fSRolf Eike Beer mmap_assert_write_locked(mm); 35217906d00cSAndrea Arcangeli 35227906d00cSAndrea Arcangeli mutex_lock(&mm_all_locks_mutex); 35237906d00cSAndrea Arcangeli 3524763ecb03SLiam R. Howlett mas_for_each(&mas, vma, ULONG_MAX) { 35257906d00cSAndrea Arcangeli if (signal_pending(current)) 35267906d00cSAndrea Arcangeli goto out_unlock; 352788f306b6SKirill A. Shutemov if (vma->vm_file && vma->vm_file->f_mapping && 352888f306b6SKirill A. Shutemov is_vm_hugetlb_page(vma)) 352988f306b6SKirill A. Shutemov vm_lock_mapping(mm, vma->vm_file->f_mapping); 353088f306b6SKirill A. Shutemov } 353188f306b6SKirill A. Shutemov 3532763ecb03SLiam R. Howlett mas_set(&mas, 0); 3533763ecb03SLiam R. Howlett mas_for_each(&mas, vma, ULONG_MAX) { 353488f306b6SKirill A. Shutemov if (signal_pending(current)) 353588f306b6SKirill A. Shutemov goto out_unlock; 353688f306b6SKirill A. Shutemov if (vma->vm_file && vma->vm_file->f_mapping && 353788f306b6SKirill A. Shutemov !is_vm_hugetlb_page(vma)) 3538454ed842SPeter Zijlstra vm_lock_mapping(mm, vma->vm_file->f_mapping); 35397906d00cSAndrea Arcangeli } 35407cd5a02fSPeter Zijlstra 3541763ecb03SLiam R. Howlett mas_set(&mas, 0); 3542763ecb03SLiam R. Howlett mas_for_each(&mas, vma, ULONG_MAX) { 35437cd5a02fSPeter Zijlstra if (signal_pending(current)) 35447cd5a02fSPeter Zijlstra goto out_unlock; 35457cd5a02fSPeter Zijlstra if (vma->anon_vma) 35465beb4930SRik van Riel list_for_each_entry(avc, &vma->anon_vma_chain, same_vma) 35475beb4930SRik van Riel vm_lock_anon_vma(mm, avc->anon_vma); 35487cd5a02fSPeter Zijlstra } 35497cd5a02fSPeter Zijlstra 3550584cff54SKautuk Consul return 0; 35517906d00cSAndrea Arcangeli 35527906d00cSAndrea Arcangeli out_unlock: 35537906d00cSAndrea Arcangeli mm_drop_all_locks(mm); 3554584cff54SKautuk Consul return -EINTR; 35557906d00cSAndrea Arcangeli } 35567906d00cSAndrea Arcangeli 35577906d00cSAndrea Arcangeli static void vm_unlock_anon_vma(struct anon_vma *anon_vma) 35587906d00cSAndrea Arcangeli { 3559f808c13fSDavidlohr Bueso if (test_bit(0, (unsigned long *) &anon_vma->root->rb_root.rb_root.rb_node)) { 35607906d00cSAndrea Arcangeli /* 35617906d00cSAndrea Arcangeli * The LSB of head.next can't change to 0 from under 35627906d00cSAndrea Arcangeli * us because we hold the mm_all_locks_mutex. 35637906d00cSAndrea Arcangeli * 35647906d00cSAndrea Arcangeli * We must however clear the bitflag before unlocking 3565bf181b9fSMichel Lespinasse * the vma so the users using the anon_vma->rb_root will 35667906d00cSAndrea Arcangeli * never see our bitflag. 35677906d00cSAndrea Arcangeli * 35687906d00cSAndrea Arcangeli * No need of atomic instructions here, head.next 35697906d00cSAndrea Arcangeli * can't change from under us until we release the 35705a505085SIngo Molnar * anon_vma->root->rwsem. 35717906d00cSAndrea Arcangeli */ 35727906d00cSAndrea Arcangeli if (!__test_and_clear_bit(0, (unsigned long *) 3573f808c13fSDavidlohr Bueso &anon_vma->root->rb_root.rb_root.rb_node)) 35747906d00cSAndrea Arcangeli BUG(); 357508b52706SKonstantin Khlebnikov anon_vma_unlock_write(anon_vma); 35767906d00cSAndrea Arcangeli } 35777906d00cSAndrea Arcangeli } 35787906d00cSAndrea Arcangeli 35797906d00cSAndrea Arcangeli static void vm_unlock_mapping(struct address_space *mapping) 35807906d00cSAndrea Arcangeli { 35817906d00cSAndrea Arcangeli if (test_bit(AS_MM_ALL_LOCKS, &mapping->flags)) { 35827906d00cSAndrea Arcangeli /* 35837906d00cSAndrea Arcangeli * AS_MM_ALL_LOCKS can't change to 0 from under us 35847906d00cSAndrea Arcangeli * because we hold the mm_all_locks_mutex. 35857906d00cSAndrea Arcangeli */ 358683cde9e8SDavidlohr Bueso i_mmap_unlock_write(mapping); 35877906d00cSAndrea Arcangeli if (!test_and_clear_bit(AS_MM_ALL_LOCKS, 35887906d00cSAndrea Arcangeli &mapping->flags)) 35897906d00cSAndrea Arcangeli BUG(); 35907906d00cSAndrea Arcangeli } 35917906d00cSAndrea Arcangeli } 35927906d00cSAndrea Arcangeli 35937906d00cSAndrea Arcangeli /* 3594c1e8d7c6SMichel Lespinasse * The mmap_lock cannot be released by the caller until 35957906d00cSAndrea Arcangeli * mm_drop_all_locks() returns. 35967906d00cSAndrea Arcangeli */ 35977906d00cSAndrea Arcangeli void mm_drop_all_locks(struct mm_struct *mm) 35987906d00cSAndrea Arcangeli { 35997906d00cSAndrea Arcangeli struct vm_area_struct *vma; 36005beb4930SRik van Riel struct anon_vma_chain *avc; 3601763ecb03SLiam R. Howlett MA_STATE(mas, &mm->mm_mt, 0, 0); 36027906d00cSAndrea Arcangeli 3603325bca1fSRolf Eike Beer mmap_assert_write_locked(mm); 36047906d00cSAndrea Arcangeli BUG_ON(!mutex_is_locked(&mm_all_locks_mutex)); 36057906d00cSAndrea Arcangeli 3606763ecb03SLiam R. Howlett mas_for_each(&mas, vma, ULONG_MAX) { 36077906d00cSAndrea Arcangeli if (vma->anon_vma) 36085beb4930SRik van Riel list_for_each_entry(avc, &vma->anon_vma_chain, same_vma) 36095beb4930SRik van Riel vm_unlock_anon_vma(avc->anon_vma); 36107906d00cSAndrea Arcangeli if (vma->vm_file && vma->vm_file->f_mapping) 36117906d00cSAndrea Arcangeli vm_unlock_mapping(vma->vm_file->f_mapping); 36127906d00cSAndrea Arcangeli } 36137906d00cSAndrea Arcangeli 36147906d00cSAndrea Arcangeli mutex_unlock(&mm_all_locks_mutex); 36157906d00cSAndrea Arcangeli } 36168feae131SDavid Howells 36178feae131SDavid Howells /* 36183edf41d8Sseokhoon.yoon * initialise the percpu counter for VM 36198feae131SDavid Howells */ 36208feae131SDavid Howells void __init mmap_init(void) 36218feae131SDavid Howells { 362200a62ce9SKOSAKI Motohiro int ret; 362300a62ce9SKOSAKI Motohiro 3624908c7f19STejun Heo ret = percpu_counter_init(&vm_committed_as, 0, GFP_KERNEL); 362500a62ce9SKOSAKI Motohiro VM_BUG_ON(ret); 36268feae131SDavid Howells } 3627c9b1d098SAndrew Shewmaker 3628c9b1d098SAndrew Shewmaker /* 3629c9b1d098SAndrew Shewmaker * Initialise sysctl_user_reserve_kbytes. 3630c9b1d098SAndrew Shewmaker * 3631c9b1d098SAndrew Shewmaker * This is intended to prevent a user from starting a single memory hogging 3632c9b1d098SAndrew Shewmaker * process, such that they cannot recover (kill the hog) in OVERCOMMIT_NEVER 3633c9b1d098SAndrew Shewmaker * mode. 3634c9b1d098SAndrew Shewmaker * 3635c9b1d098SAndrew Shewmaker * The default value is min(3% of free memory, 128MB) 3636c9b1d098SAndrew Shewmaker * 128MB is enough to recover with sshd/login, bash, and top/kill. 3637c9b1d098SAndrew Shewmaker */ 36381640879aSAndrew Shewmaker static int init_user_reserve(void) 3639c9b1d098SAndrew Shewmaker { 3640c9b1d098SAndrew Shewmaker unsigned long free_kbytes; 3641c9b1d098SAndrew Shewmaker 3642c41f012aSMichal Hocko free_kbytes = global_zone_page_state(NR_FREE_PAGES) << (PAGE_SHIFT - 10); 3643c9b1d098SAndrew Shewmaker 3644c9b1d098SAndrew Shewmaker sysctl_user_reserve_kbytes = min(free_kbytes / 32, 1UL << 17); 3645c9b1d098SAndrew Shewmaker return 0; 3646c9b1d098SAndrew Shewmaker } 3647a64fb3cdSPaul Gortmaker subsys_initcall(init_user_reserve); 36484eeab4f5SAndrew Shewmaker 36494eeab4f5SAndrew Shewmaker /* 36504eeab4f5SAndrew Shewmaker * Initialise sysctl_admin_reserve_kbytes. 36514eeab4f5SAndrew Shewmaker * 36524eeab4f5SAndrew Shewmaker * The purpose of sysctl_admin_reserve_kbytes is to allow the sys admin 36534eeab4f5SAndrew Shewmaker * to log in and kill a memory hogging process. 36544eeab4f5SAndrew Shewmaker * 36554eeab4f5SAndrew Shewmaker * Systems with more than 256MB will reserve 8MB, enough to recover 36564eeab4f5SAndrew Shewmaker * with sshd, bash, and top in OVERCOMMIT_GUESS. Smaller systems will 36574eeab4f5SAndrew Shewmaker * only reserve 3% of free pages by default. 36584eeab4f5SAndrew Shewmaker */ 36591640879aSAndrew Shewmaker static int init_admin_reserve(void) 36604eeab4f5SAndrew Shewmaker { 36614eeab4f5SAndrew Shewmaker unsigned long free_kbytes; 36624eeab4f5SAndrew Shewmaker 3663c41f012aSMichal Hocko free_kbytes = global_zone_page_state(NR_FREE_PAGES) << (PAGE_SHIFT - 10); 36644eeab4f5SAndrew Shewmaker 36654eeab4f5SAndrew Shewmaker sysctl_admin_reserve_kbytes = min(free_kbytes / 32, 1UL << 13); 36664eeab4f5SAndrew Shewmaker return 0; 36674eeab4f5SAndrew Shewmaker } 3668a64fb3cdSPaul Gortmaker subsys_initcall(init_admin_reserve); 36691640879aSAndrew Shewmaker 36701640879aSAndrew Shewmaker /* 36711640879aSAndrew Shewmaker * Reinititalise user and admin reserves if memory is added or removed. 36721640879aSAndrew Shewmaker * 36731640879aSAndrew Shewmaker * The default user reserve max is 128MB, and the default max for the 36741640879aSAndrew Shewmaker * admin reserve is 8MB. These are usually, but not always, enough to 36751640879aSAndrew Shewmaker * enable recovery from a memory hogging process using login/sshd, a shell, 36761640879aSAndrew Shewmaker * and tools like top. It may make sense to increase or even disable the 36771640879aSAndrew Shewmaker * reserve depending on the existence of swap or variations in the recovery 36781640879aSAndrew Shewmaker * tools. So, the admin may have changed them. 36791640879aSAndrew Shewmaker * 36801640879aSAndrew Shewmaker * If memory is added and the reserves have been eliminated or increased above 36811640879aSAndrew Shewmaker * the default max, then we'll trust the admin. 36821640879aSAndrew Shewmaker * 36831640879aSAndrew Shewmaker * If memory is removed and there isn't enough free memory, then we 36841640879aSAndrew Shewmaker * need to reset the reserves. 36851640879aSAndrew Shewmaker * 36861640879aSAndrew Shewmaker * Otherwise keep the reserve set by the admin. 36871640879aSAndrew Shewmaker */ 36881640879aSAndrew Shewmaker static int reserve_mem_notifier(struct notifier_block *nb, 36891640879aSAndrew Shewmaker unsigned long action, void *data) 36901640879aSAndrew Shewmaker { 36911640879aSAndrew Shewmaker unsigned long tmp, free_kbytes; 36921640879aSAndrew Shewmaker 36931640879aSAndrew Shewmaker switch (action) { 36941640879aSAndrew Shewmaker case MEM_ONLINE: 36951640879aSAndrew Shewmaker /* Default max is 128MB. Leave alone if modified by operator. */ 36961640879aSAndrew Shewmaker tmp = sysctl_user_reserve_kbytes; 36971640879aSAndrew Shewmaker if (0 < tmp && tmp < (1UL << 17)) 36981640879aSAndrew Shewmaker init_user_reserve(); 36991640879aSAndrew Shewmaker 37001640879aSAndrew Shewmaker /* Default max is 8MB. Leave alone if modified by operator. */ 37011640879aSAndrew Shewmaker tmp = sysctl_admin_reserve_kbytes; 37021640879aSAndrew Shewmaker if (0 < tmp && tmp < (1UL << 13)) 37031640879aSAndrew Shewmaker init_admin_reserve(); 37041640879aSAndrew Shewmaker 37051640879aSAndrew Shewmaker break; 37061640879aSAndrew Shewmaker case MEM_OFFLINE: 3707c41f012aSMichal Hocko free_kbytes = global_zone_page_state(NR_FREE_PAGES) << (PAGE_SHIFT - 10); 37081640879aSAndrew Shewmaker 37091640879aSAndrew Shewmaker if (sysctl_user_reserve_kbytes > free_kbytes) { 37101640879aSAndrew Shewmaker init_user_reserve(); 37111640879aSAndrew Shewmaker pr_info("vm.user_reserve_kbytes reset to %lu\n", 37121640879aSAndrew Shewmaker sysctl_user_reserve_kbytes); 37131640879aSAndrew Shewmaker } 37141640879aSAndrew Shewmaker 37151640879aSAndrew Shewmaker if (sysctl_admin_reserve_kbytes > free_kbytes) { 37161640879aSAndrew Shewmaker init_admin_reserve(); 37171640879aSAndrew Shewmaker pr_info("vm.admin_reserve_kbytes reset to %lu\n", 37181640879aSAndrew Shewmaker sysctl_admin_reserve_kbytes); 37191640879aSAndrew Shewmaker } 37201640879aSAndrew Shewmaker break; 37211640879aSAndrew Shewmaker default: 37221640879aSAndrew Shewmaker break; 37231640879aSAndrew Shewmaker } 37241640879aSAndrew Shewmaker return NOTIFY_OK; 37251640879aSAndrew Shewmaker } 37261640879aSAndrew Shewmaker 37271640879aSAndrew Shewmaker static int __meminit init_reserve_notifier(void) 37281640879aSAndrew Shewmaker { 37291eeaa4fdSLiu Shixin if (hotplug_memory_notifier(reserve_mem_notifier, DEFAULT_CALLBACK_PRI)) 3730b1de0d13SMitchel Humpherys pr_err("Failed registering memory add/remove notifier for admin reserve\n"); 37311640879aSAndrew Shewmaker 37321640879aSAndrew Shewmaker return 0; 37331640879aSAndrew Shewmaker } 3734a64fb3cdSPaul Gortmaker subsys_initcall(init_reserve_notifier); 3735