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 5280fd5a9e2SLiam R. Howlett /* VMA iterator points to previous, so set to start if necessary */ 5290fd5a9e2SLiam R. Howlett if (vma_iter_addr(vmi) != start) 5300fd5a9e2SLiam R. Howlett vma_iter_set(vmi, start); 5310fd5a9e2SLiam R. Howlett 5324dd1b841SLiam R. Howlett vma->vm_start = start; 5334dd1b841SLiam R. Howlett vma->vm_end = end; 5344dd1b841SLiam R. Howlett vma->vm_pgoff = pgoff; 5353c441ab7SLiam R. Howlett vma_iter_store(vmi, vma); 5364dd1b841SLiam R. Howlett 5374dd1b841SLiam R. Howlett if (file) { 5384dd1b841SLiam R. Howlett vma_interval_tree_insert(vma, root); 5394dd1b841SLiam R. Howlett flush_dcache_mmap_unlock(mapping); 5404dd1b841SLiam R. Howlett } 5414dd1b841SLiam R. Howlett 5424dd1b841SLiam R. Howlett /* Expanding over the next vma */ 543763ecb03SLiam R. Howlett if (remove_next && file) { 5444dd1b841SLiam R. Howlett __remove_shared_vm_struct(next, file, mapping); 5454dd1b841SLiam R. Howlett } 5464dd1b841SLiam R. Howlett 5474dd1b841SLiam R. Howlett if (anon_vma) { 5484dd1b841SLiam R. Howlett anon_vma_interval_tree_post_update_vma(vma); 5494dd1b841SLiam R. Howlett anon_vma_unlock_write(anon_vma); 5504dd1b841SLiam R. Howlett } 5514dd1b841SLiam R. Howlett 5524dd1b841SLiam R. Howlett if (file) { 5534dd1b841SLiam R. Howlett i_mmap_unlock_write(mapping); 5544dd1b841SLiam R. Howlett uprobe_mmap(vma); 5554dd1b841SLiam R. Howlett } 5564dd1b841SLiam R. Howlett 5574dd1b841SLiam R. Howlett if (remove_next) { 5584dd1b841SLiam R. Howlett if (file) { 5594dd1b841SLiam R. Howlett uprobe_munmap(next, next->vm_start, next->vm_end); 5604dd1b841SLiam R. Howlett fput(file); 5614dd1b841SLiam R. Howlett } 5624dd1b841SLiam R. Howlett if (next->anon_vma) 5634dd1b841SLiam R. Howlett anon_vma_merge(vma, next); 5644dd1b841SLiam R. Howlett mm->map_count--; 5654dd1b841SLiam R. Howlett mpol_put(vma_policy(next)); 5664dd1b841SLiam R. Howlett vm_area_free(next); 5674dd1b841SLiam R. Howlett } 5684dd1b841SLiam R. Howlett 5694dd1b841SLiam R. Howlett validate_mm(mm); 5704dd1b841SLiam R. Howlett return 0; 5714dd1b841SLiam R. Howlett 5724dd1b841SLiam R. Howlett nomem: 5734dd1b841SLiam R. Howlett return -ENOMEM; 5744dd1b841SLiam R. Howlett } 5754dd1b841SLiam R. Howlett 5764dd1b841SLiam R. Howlett /* 577*440703e0SLiam R. Howlett * vma_prepare() - Helper function for handling locking VMAs prior to altering 578*440703e0SLiam R. Howlett * @vp: The initialized vma_prepare struct 579*440703e0SLiam R. Howlett */ 580*440703e0SLiam R. Howlett static inline void vma_prepare(struct vma_prepare *vp) 581*440703e0SLiam R. Howlett { 582*440703e0SLiam R. Howlett if (vp->file) { 583*440703e0SLiam R. Howlett uprobe_munmap(vp->vma, vp->vma->vm_start, vp->vma->vm_end); 584*440703e0SLiam R. Howlett 585*440703e0SLiam R. Howlett if (vp->adj_next) 586*440703e0SLiam R. Howlett uprobe_munmap(vp->adj_next, vp->adj_next->vm_start, 587*440703e0SLiam R. Howlett vp->adj_next->vm_end); 588*440703e0SLiam R. Howlett 589*440703e0SLiam R. Howlett i_mmap_lock_write(vp->mapping); 590*440703e0SLiam R. Howlett if (vp->insert && vp->insert->vm_file) { 591*440703e0SLiam R. Howlett /* 592*440703e0SLiam R. Howlett * Put into interval tree now, so instantiated pages 593*440703e0SLiam R. Howlett * are visible to arm/parisc __flush_dcache_page 594*440703e0SLiam R. Howlett * throughout; but we cannot insert into address 595*440703e0SLiam R. Howlett * space until vma start or end is updated. 596*440703e0SLiam R. Howlett */ 597*440703e0SLiam R. Howlett __vma_link_file(vp->insert, 598*440703e0SLiam R. Howlett vp->insert->vm_file->f_mapping); 599*440703e0SLiam R. Howlett } 600*440703e0SLiam R. Howlett } 601*440703e0SLiam R. Howlett 602*440703e0SLiam R. Howlett if (vp->anon_vma) { 603*440703e0SLiam R. Howlett anon_vma_lock_write(vp->anon_vma); 604*440703e0SLiam R. Howlett anon_vma_interval_tree_pre_update_vma(vp->vma); 605*440703e0SLiam R. Howlett if (vp->adj_next) 606*440703e0SLiam R. Howlett anon_vma_interval_tree_pre_update_vma(vp->adj_next); 607*440703e0SLiam R. Howlett } 608*440703e0SLiam R. Howlett 609*440703e0SLiam R. Howlett if (vp->file) { 610*440703e0SLiam R. Howlett flush_dcache_mmap_lock(vp->mapping); 611*440703e0SLiam R. Howlett vma_interval_tree_remove(vp->vma, &vp->mapping->i_mmap); 612*440703e0SLiam R. Howlett if (vp->adj_next) 613*440703e0SLiam R. Howlett vma_interval_tree_remove(vp->adj_next, 614*440703e0SLiam R. Howlett &vp->mapping->i_mmap); 615*440703e0SLiam R. Howlett } 616*440703e0SLiam R. Howlett 617*440703e0SLiam R. Howlett } 618*440703e0SLiam R. Howlett 619*440703e0SLiam R. Howlett /* 620*440703e0SLiam R. Howlett * vma_complete- Helper function for handling the unlocking after altering VMAs, 621*440703e0SLiam R. Howlett * or for inserting a VMA. 622*440703e0SLiam R. Howlett * 623*440703e0SLiam R. Howlett * @vp: The vma_prepare struct 624*440703e0SLiam R. Howlett * @vmi: The vma iterator 625*440703e0SLiam R. Howlett * @mm: The mm_struct 626*440703e0SLiam R. Howlett */ 627*440703e0SLiam R. Howlett static inline void vma_complete(struct vma_prepare *vp, 628*440703e0SLiam R. Howlett struct vma_iterator *vmi, struct mm_struct *mm) 629*440703e0SLiam R. Howlett { 630*440703e0SLiam R. Howlett if (vp->file) { 631*440703e0SLiam R. Howlett if (vp->adj_next) 632*440703e0SLiam R. Howlett vma_interval_tree_insert(vp->adj_next, 633*440703e0SLiam R. Howlett &vp->mapping->i_mmap); 634*440703e0SLiam R. Howlett vma_interval_tree_insert(vp->vma, &vp->mapping->i_mmap); 635*440703e0SLiam R. Howlett flush_dcache_mmap_unlock(vp->mapping); 636*440703e0SLiam R. Howlett } 637*440703e0SLiam R. Howlett 638*440703e0SLiam R. Howlett if (vp->remove && vp->file) { 639*440703e0SLiam R. Howlett __remove_shared_vm_struct(vp->remove, vp->file, vp->mapping); 640*440703e0SLiam R. Howlett if (vp->remove2) 641*440703e0SLiam R. Howlett __remove_shared_vm_struct(vp->remove2, vp->file, 642*440703e0SLiam R. Howlett vp->mapping); 643*440703e0SLiam R. Howlett } else if (vp->insert) { 644*440703e0SLiam R. Howlett /* 645*440703e0SLiam R. Howlett * split_vma has split insert from vma, and needs 646*440703e0SLiam R. Howlett * us to insert it before dropping the locks 647*440703e0SLiam R. Howlett * (it may either follow vma or precede it). 648*440703e0SLiam R. Howlett */ 649*440703e0SLiam R. Howlett vma_iter_store(vmi, vp->insert); 650*440703e0SLiam R. Howlett mm->map_count++; 651*440703e0SLiam R. Howlett } 652*440703e0SLiam R. Howlett 653*440703e0SLiam R. Howlett if (vp->anon_vma) { 654*440703e0SLiam R. Howlett anon_vma_interval_tree_post_update_vma(vp->vma); 655*440703e0SLiam R. Howlett if (vp->adj_next) 656*440703e0SLiam R. Howlett anon_vma_interval_tree_post_update_vma(vp->adj_next); 657*440703e0SLiam R. Howlett anon_vma_unlock_write(vp->anon_vma); 658*440703e0SLiam R. Howlett } 659*440703e0SLiam R. Howlett 660*440703e0SLiam R. Howlett if (vp->file) { 661*440703e0SLiam R. Howlett i_mmap_unlock_write(vp->mapping); 662*440703e0SLiam R. Howlett uprobe_mmap(vp->vma); 663*440703e0SLiam R. Howlett 664*440703e0SLiam R. Howlett if (vp->adj_next) 665*440703e0SLiam R. Howlett uprobe_mmap(vp->adj_next); 666*440703e0SLiam R. Howlett } 667*440703e0SLiam R. Howlett 668*440703e0SLiam R. Howlett if (vp->remove) { 669*440703e0SLiam R. Howlett again: 670*440703e0SLiam R. Howlett if (vp->file) { 671*440703e0SLiam R. Howlett uprobe_munmap(vp->remove, vp->remove->vm_start, 672*440703e0SLiam R. Howlett vp->remove->vm_end); 673*440703e0SLiam R. Howlett fput(vp->file); 674*440703e0SLiam R. Howlett } 675*440703e0SLiam R. Howlett if (vp->remove->anon_vma) 676*440703e0SLiam R. Howlett anon_vma_merge(vp->vma, vp->remove); 677*440703e0SLiam R. Howlett mm->map_count--; 678*440703e0SLiam R. Howlett mpol_put(vma_policy(vp->remove)); 679*440703e0SLiam R. Howlett if (!vp->remove2) 680*440703e0SLiam R. Howlett WARN_ON_ONCE(vp->vma->vm_end < vp->remove->vm_end); 681*440703e0SLiam R. Howlett vm_area_free(vp->remove); 682*440703e0SLiam R. Howlett 683*440703e0SLiam R. Howlett /* 684*440703e0SLiam R. Howlett * In mprotect's case 6 (see comments on vma_merge), 685*440703e0SLiam R. Howlett * we must remove next_next too. 686*440703e0SLiam R. Howlett */ 687*440703e0SLiam R. Howlett if (vp->remove2) { 688*440703e0SLiam R. Howlett vp->remove = vp->remove2; 689*440703e0SLiam R. Howlett vp->remove2 = NULL; 690*440703e0SLiam R. Howlett goto again; 691*440703e0SLiam R. Howlett } 692*440703e0SLiam R. Howlett } 693*440703e0SLiam R. Howlett if (vp->insert && vp->file) 694*440703e0SLiam R. Howlett uprobe_mmap(vp->insert); 695*440703e0SLiam R. Howlett } 696*440703e0SLiam R. Howlett 697*440703e0SLiam R. Howlett /* 6981da177e4SLinus Torvalds * We cannot adjust vm_start, vm_end, vm_pgoff fields of a vma that 6991da177e4SLinus Torvalds * is already present in an i_mmap tree without adjusting the tree. 7001da177e4SLinus Torvalds * The following helper function should be used when such adjustments 7011da177e4SLinus Torvalds * are necessary. The "insert" vma (if any) is to be inserted 7021da177e4SLinus Torvalds * before we drop the necessary locks. 7031da177e4SLinus Torvalds */ 7049e560446SLiam R. Howlett int __vma_adjust(struct vma_iterator *vmi, struct vm_area_struct *vma, 7059e560446SLiam R. Howlett unsigned long start, unsigned long end, pgoff_t pgoff, 7069e560446SLiam R. Howlett struct vm_area_struct *insert, struct vm_area_struct *expand) 7071da177e4SLinus Torvalds { 7081da177e4SLinus Torvalds struct mm_struct *mm = vma->vm_mm; 7091cd916d0SAndrew Morton struct vm_area_struct *next_next = NULL; /* uninit var warning */ 7101cd916d0SAndrew Morton struct vm_area_struct *next = find_vma(mm, vma->vm_end); 711524e00b3SLiam R. Howlett struct vm_area_struct *orig_vma = vma; 712012f1800SRik van Riel struct anon_vma *anon_vma = NULL; 7131da177e4SLinus Torvalds struct file *file = vma->vm_file; 714524e00b3SLiam R. Howlett bool vma_changed = false; 7151da177e4SLinus Torvalds long adjust_next = 0; 7161da177e4SLinus Torvalds int remove_next = 0; 717734537c9SKirill A. Shutemov struct vm_area_struct *exporter = NULL, *importer = NULL; 718*440703e0SLiam R. Howlett struct vma_prepare vma_prep; 719287d97acSLinus Torvalds 720d4af56c5SLiam R. Howlett if (next && !insert) { 7211da177e4SLinus Torvalds if (end >= next->vm_end) { 7221da177e4SLinus Torvalds /* 7231da177e4SLinus Torvalds * vma expands, overlapping all the next, and 7241da177e4SLinus Torvalds * perhaps the one after too (mprotect case 6). 72586d12e47SAndrea Arcangeli * The only other cases that gets here are 726e86f15eeSAndrea Arcangeli * case 1, case 7 and case 8. 727e86f15eeSAndrea Arcangeli */ 728e86f15eeSAndrea Arcangeli if (next == expand) { 729e86f15eeSAndrea Arcangeli /* 730e86f15eeSAndrea Arcangeli * The only case where we don't expand "vma" 731e86f15eeSAndrea Arcangeli * and we expand "next" instead is case 8. 732e86f15eeSAndrea Arcangeli */ 733e86f15eeSAndrea Arcangeli VM_WARN_ON(end != next->vm_end); 734e86f15eeSAndrea Arcangeli /* 735e86f15eeSAndrea Arcangeli * remove_next == 3 means we're 736e86f15eeSAndrea Arcangeli * removing "vma" and that to do so we 737e86f15eeSAndrea Arcangeli * swapped "vma" and "next". 738e86f15eeSAndrea Arcangeli */ 739e86f15eeSAndrea Arcangeli remove_next = 3; 740e86f15eeSAndrea Arcangeli VM_WARN_ON(file != next->vm_file); 741e86f15eeSAndrea Arcangeli swap(vma, next); 742e86f15eeSAndrea Arcangeli } else { 743e86f15eeSAndrea Arcangeli VM_WARN_ON(expand != vma); 744e86f15eeSAndrea Arcangeli /* 745e86f15eeSAndrea Arcangeli * case 1, 6, 7, remove_next == 2 is case 6, 746e86f15eeSAndrea Arcangeli * remove_next == 1 is case 1 or 7. 7471da177e4SLinus Torvalds */ 748734537c9SKirill A. Shutemov remove_next = 1 + (end > next->vm_end); 749d4af56c5SLiam R. Howlett if (remove_next == 2) 750d4af56c5SLiam R. Howlett next_next = find_vma(mm, next->vm_end); 751d4af56c5SLiam R. Howlett 752e86f15eeSAndrea Arcangeli VM_WARN_ON(remove_next == 2 && 753763ecb03SLiam R. Howlett end != next_next->vm_end); 754e86f15eeSAndrea Arcangeli } 755e86f15eeSAndrea Arcangeli 756287d97acSLinus Torvalds exporter = next; 7571da177e4SLinus Torvalds importer = vma; 758734537c9SKirill A. Shutemov 759734537c9SKirill A. Shutemov /* 760734537c9SKirill A. Shutemov * If next doesn't have anon_vma, import from vma after 761734537c9SKirill A. Shutemov * next, if the vma overlaps with it. 762734537c9SKirill A. Shutemov */ 76397a42cd4SAndrea Arcangeli if (remove_next == 2 && !next->anon_vma) 764763ecb03SLiam R. Howlett exporter = next_next; 765734537c9SKirill A. Shutemov 7661da177e4SLinus Torvalds } else if (end > next->vm_start) { 7671da177e4SLinus Torvalds /* 7681da177e4SLinus Torvalds * vma expands, overlapping part of the next: 7691da177e4SLinus Torvalds * mprotect case 5 shifting the boundary up. 7701da177e4SLinus Torvalds */ 771f9d86a60SWei Yang adjust_next = (end - next->vm_start); 772287d97acSLinus Torvalds exporter = next; 7731da177e4SLinus Torvalds importer = vma; 774e86f15eeSAndrea Arcangeli VM_WARN_ON(expand != importer); 7751da177e4SLinus Torvalds } else if (end < vma->vm_end) { 7761da177e4SLinus Torvalds /* 7771da177e4SLinus Torvalds * vma shrinks, and !insert tells it's not 7781da177e4SLinus Torvalds * split_vma inserting another: so it must be 7791da177e4SLinus Torvalds * mprotect case 4 shifting the boundary down. 7801da177e4SLinus Torvalds */ 781f9d86a60SWei Yang adjust_next = -(vma->vm_end - end); 782287d97acSLinus Torvalds exporter = vma; 7831da177e4SLinus Torvalds importer = next; 784e86f15eeSAndrea Arcangeli VM_WARN_ON(expand != importer); 7851da177e4SLinus Torvalds } 7861da177e4SLinus Torvalds 7875beb4930SRik van Riel /* 7885beb4930SRik van Riel * Easily overlooked: when mprotect shifts the boundary, 7895beb4930SRik van Riel * make sure the expanding vma has anon_vma set if the 7905beb4930SRik van Riel * shrinking vma had, to cover any anon pages imported. 7915beb4930SRik van Riel */ 792287d97acSLinus Torvalds if (exporter && exporter->anon_vma && !importer->anon_vma) { 793c4ea95d7SDaniel Forrest int error; 794c4ea95d7SDaniel Forrest 795287d97acSLinus Torvalds importer->anon_vma = exporter->anon_vma; 796b800c91aSKonstantin Khlebnikov error = anon_vma_clone(importer, exporter); 7973fe89b3eSLeon Yu if (error) 798b800c91aSKonstantin Khlebnikov return error; 799b800c91aSKonstantin Khlebnikov } 8005beb4930SRik van Riel } 80137f9f559SKirill A. Shutemov 8029e560446SLiam R. Howlett if (vma_iter_prealloc(vmi)) 803d4af56c5SLiam R. Howlett return -ENOMEM; 804d4af56c5SLiam R. Howlett 805e3d73f84SLiam R. Howlett anon_vma = vma->anon_vma; 806e3d73f84SLiam R. Howlett if (!anon_vma && adjust_next) 807e3d73f84SLiam R. Howlett anon_vma = next->anon_vma; 808e3d73f84SLiam R. Howlett 809e3d73f84SLiam R. Howlett if (anon_vma) 810e3d73f84SLiam R. Howlett VM_WARN_ON(adjust_next && next->anon_vma && 811e3d73f84SLiam R. Howlett anon_vma != next->anon_vma); 812e3d73f84SLiam R. Howlett 813d4af56c5SLiam R. Howlett vma_adjust_trans_huge(orig_vma, start, end, adjust_next); 814682968e0SSrikar Dronamraju 815*440703e0SLiam R. Howlett memset(&vma_prep, 0, sizeof(vma_prep)); 816*440703e0SLiam R. Howlett vma_prep.vma = vma; 817*440703e0SLiam R. Howlett vma_prep.anon_vma = anon_vma; 818*440703e0SLiam R. Howlett vma_prep.file = file; 819682968e0SSrikar Dronamraju if (adjust_next) 820*440703e0SLiam R. Howlett vma_prep.adj_next = next; 821*440703e0SLiam R. Howlett if (file) 822*440703e0SLiam R. Howlett vma_prep.mapping = file->f_mapping; 823*440703e0SLiam R. Howlett vma_prep.insert = insert; 824*440703e0SLiam R. Howlett if (remove_next) { 825*440703e0SLiam R. Howlett vma_prep.remove = next; 826*440703e0SLiam R. Howlett vma_prep.remove2 = next_next; 8271da177e4SLinus Torvalds } 8281da177e4SLinus Torvalds 829*440703e0SLiam R. Howlett vma_prepare(&vma_prep); 8301da177e4SLinus Torvalds 831d3737187SMichel Lespinasse if (start != vma->vm_start) { 832c465be97SLiam R. Howlett if (vma->vm_start < start) { 833c465be97SLiam R. Howlett if (!insert || (insert->vm_end != start)) { 8349e560446SLiam R. Howlett vma_iter_clear(vmi, vma->vm_start, start); 835c465be97SLiam R. Howlett vma_iter_set(vmi, start); 8363b0e81a1SLiam R. Howlett VM_WARN_ON(insert && insert->vm_start > vma->vm_start); 837c465be97SLiam R. Howlett } 8383b0e81a1SLiam R. Howlett } else { 839524e00b3SLiam R. Howlett vma_changed = true; 8403b0e81a1SLiam R. Howlett } 8411da177e4SLinus Torvalds vma->vm_start = start; 842d3737187SMichel Lespinasse } 843d3737187SMichel Lespinasse if (end != vma->vm_end) { 8443b0e81a1SLiam R. Howlett if (vma->vm_end > end) { 8453b0e81a1SLiam R. Howlett if (!insert || (insert->vm_start != end)) { 8469e560446SLiam R. Howlett vma_iter_clear(vmi, end, vma->vm_end); 8479e560446SLiam R. Howlett vma_iter_set(vmi, vma->vm_end); 8483b0e81a1SLiam R. Howlett VM_WARN_ON(insert && 8493b0e81a1SLiam R. Howlett insert->vm_end < vma->vm_end); 8503b0e81a1SLiam R. Howlett } 8513b0e81a1SLiam R. Howlett } else { 852524e00b3SLiam R. Howlett vma_changed = true; 8533b0e81a1SLiam R. Howlett } 8541da177e4SLinus Torvalds vma->vm_end = end; 855d3737187SMichel Lespinasse } 856d4af56c5SLiam R. Howlett 857524e00b3SLiam R. Howlett if (vma_changed) 8589e560446SLiam R. Howlett vma_iter_store(vmi, vma); 859d4af56c5SLiam R. Howlett 8601da177e4SLinus Torvalds vma->vm_pgoff = pgoff; 8611da177e4SLinus Torvalds if (adjust_next) { 862f9d86a60SWei Yang next->vm_start += adjust_next; 863f9d86a60SWei Yang next->vm_pgoff += adjust_next >> PAGE_SHIFT; 8649e560446SLiam R. Howlett vma_iter_store(vmi, next); 8651da177e4SLinus Torvalds } 8661da177e4SLinus Torvalds 867*440703e0SLiam R. Howlett vma_complete(&vma_prep, vmi, mm); 8689e560446SLiam R. Howlett vma_iter_free(vmi); 8691da177e4SLinus Torvalds validate_mm(mm); 870763ecb03SLiam R. Howlett 8715beb4930SRik van Riel return 0; 8721da177e4SLinus Torvalds } 8731da177e4SLinus Torvalds 8741da177e4SLinus Torvalds /* 8751da177e4SLinus Torvalds * If the vma has a ->close operation then the driver probably needs to release 8761da177e4SLinus Torvalds * per-vma resources, so we don't attempt to merge those. 8771da177e4SLinus Torvalds */ 8781da177e4SLinus Torvalds static inline int is_mergeable_vma(struct vm_area_struct *vma, 87919a809afSAndrea Arcangeli struct file *file, unsigned long vm_flags, 8809a10064fSColin Cross struct vm_userfaultfd_ctx vm_userfaultfd_ctx, 8815c26f6acSSuren Baghdasaryan struct anon_vma_name *anon_name) 8821da177e4SLinus Torvalds { 88334228d47SCyrill Gorcunov /* 88434228d47SCyrill Gorcunov * VM_SOFTDIRTY should not prevent from VMA merging, if we 88534228d47SCyrill Gorcunov * match the flags but dirty bit -- the caller should mark 88634228d47SCyrill Gorcunov * merged VMA as dirty. If dirty bit won't be excluded from 8878bb4e7a2SWei Yang * comparison, we increase pressure on the memory system forcing 88834228d47SCyrill Gorcunov * the kernel to generate new VMAs when old one could be 88934228d47SCyrill Gorcunov * extended instead. 89034228d47SCyrill Gorcunov */ 89134228d47SCyrill Gorcunov if ((vma->vm_flags ^ vm_flags) & ~VM_SOFTDIRTY) 8921da177e4SLinus Torvalds return 0; 8931da177e4SLinus Torvalds if (vma->vm_file != file) 8941da177e4SLinus Torvalds return 0; 8951da177e4SLinus Torvalds if (vma->vm_ops && vma->vm_ops->close) 8961da177e4SLinus Torvalds return 0; 89719a809afSAndrea Arcangeli if (!is_mergeable_vm_userfaultfd_ctx(vma, vm_userfaultfd_ctx)) 89819a809afSAndrea Arcangeli return 0; 8995c26f6acSSuren Baghdasaryan if (!anon_vma_name_eq(anon_vma_name(vma), anon_name)) 9009a10064fSColin Cross return 0; 9011da177e4SLinus Torvalds return 1; 9021da177e4SLinus Torvalds } 9031da177e4SLinus Torvalds 9041da177e4SLinus Torvalds static inline int is_mergeable_anon_vma(struct anon_vma *anon_vma1, 905965f55deSShaohua Li struct anon_vma *anon_vma2, 906965f55deSShaohua Li struct vm_area_struct *vma) 9071da177e4SLinus Torvalds { 908965f55deSShaohua Li /* 909965f55deSShaohua Li * The list_is_singular() test is to avoid merging VMA cloned from 910965f55deSShaohua Li * parents. This can improve scalability caused by anon_vma lock. 911965f55deSShaohua Li */ 912965f55deSShaohua Li if ((!anon_vma1 || !anon_vma2) && (!vma || 913965f55deSShaohua Li list_is_singular(&vma->anon_vma_chain))) 914965f55deSShaohua Li return 1; 915965f55deSShaohua Li return anon_vma1 == anon_vma2; 9161da177e4SLinus Torvalds } 9171da177e4SLinus Torvalds 9181da177e4SLinus Torvalds /* 9191da177e4SLinus Torvalds * Return true if we can merge this (vm_flags,anon_vma,file,vm_pgoff) 9201da177e4SLinus Torvalds * in front of (at a lower virtual address and file offset than) the vma. 9211da177e4SLinus Torvalds * 9221da177e4SLinus Torvalds * We cannot merge two vmas if they have differently assigned (non-NULL) 9231da177e4SLinus Torvalds * anon_vmas, nor if same anon_vma is assigned but offsets incompatible. 9241da177e4SLinus Torvalds * 9251da177e4SLinus Torvalds * We don't check here for the merged mmap wrapping around the end of pagecache 92645e55300SPeter Collingbourne * indices (16TB on ia32) because do_mmap() does not permit mmap's which 9271da177e4SLinus Torvalds * wrap, nor mmaps which cover the final page at index -1UL. 9281da177e4SLinus Torvalds */ 9291da177e4SLinus Torvalds static int 9301da177e4SLinus Torvalds can_vma_merge_before(struct vm_area_struct *vma, unsigned long vm_flags, 93119a809afSAndrea Arcangeli struct anon_vma *anon_vma, struct file *file, 93219a809afSAndrea Arcangeli pgoff_t vm_pgoff, 9339a10064fSColin Cross struct vm_userfaultfd_ctx vm_userfaultfd_ctx, 9345c26f6acSSuren Baghdasaryan struct anon_vma_name *anon_name) 9351da177e4SLinus Torvalds { 9369a10064fSColin Cross if (is_mergeable_vma(vma, file, vm_flags, vm_userfaultfd_ctx, anon_name) && 937965f55deSShaohua Li is_mergeable_anon_vma(anon_vma, vma->anon_vma, vma)) { 9381da177e4SLinus Torvalds if (vma->vm_pgoff == vm_pgoff) 9391da177e4SLinus Torvalds return 1; 9401da177e4SLinus Torvalds } 9411da177e4SLinus Torvalds return 0; 9421da177e4SLinus Torvalds } 9431da177e4SLinus Torvalds 9441da177e4SLinus Torvalds /* 9451da177e4SLinus Torvalds * Return true if we can merge this (vm_flags,anon_vma,file,vm_pgoff) 9461da177e4SLinus Torvalds * beyond (at a higher virtual address and file offset than) the vma. 9471da177e4SLinus Torvalds * 9481da177e4SLinus Torvalds * We cannot merge two vmas if they have differently assigned (non-NULL) 9491da177e4SLinus Torvalds * anon_vmas, nor if same anon_vma is assigned but offsets incompatible. 9501da177e4SLinus Torvalds */ 9511da177e4SLinus Torvalds static int 9521da177e4SLinus Torvalds can_vma_merge_after(struct vm_area_struct *vma, unsigned long vm_flags, 95319a809afSAndrea Arcangeli struct anon_vma *anon_vma, struct file *file, 95419a809afSAndrea Arcangeli pgoff_t vm_pgoff, 9559a10064fSColin Cross struct vm_userfaultfd_ctx vm_userfaultfd_ctx, 9565c26f6acSSuren Baghdasaryan struct anon_vma_name *anon_name) 9571da177e4SLinus Torvalds { 9589a10064fSColin Cross if (is_mergeable_vma(vma, file, vm_flags, vm_userfaultfd_ctx, anon_name) && 959965f55deSShaohua Li is_mergeable_anon_vma(anon_vma, vma->anon_vma, vma)) { 9601da177e4SLinus Torvalds pgoff_t vm_pglen; 961d6e93217SLibin vm_pglen = vma_pages(vma); 9621da177e4SLinus Torvalds if (vma->vm_pgoff + vm_pglen == vm_pgoff) 9631da177e4SLinus Torvalds return 1; 9641da177e4SLinus Torvalds } 9651da177e4SLinus Torvalds return 0; 9661da177e4SLinus Torvalds } 9671da177e4SLinus Torvalds 9681da177e4SLinus Torvalds /* 9699a10064fSColin Cross * Given a mapping request (addr,end,vm_flags,file,pgoff,anon_name), 9709a10064fSColin Cross * figure out whether that can be merged with its predecessor or its 9719a10064fSColin Cross * successor. Or both (it neatly fills a hole). 9721da177e4SLinus Torvalds * 9731da177e4SLinus Torvalds * In most cases - when called for mmap, brk or mremap - [addr,end) is 9741da177e4SLinus Torvalds * certain not to be mapped by the time vma_merge is called; but when 9751da177e4SLinus Torvalds * called for mprotect, it is certain to be already mapped (either at 9761da177e4SLinus Torvalds * an offset within prev, or at the start of next), and the flags of 9771da177e4SLinus Torvalds * this area are about to be changed to vm_flags - and the no-change 9781da177e4SLinus Torvalds * case has already been eliminated. 9791da177e4SLinus Torvalds * 9801da177e4SLinus Torvalds * The following mprotect cases have to be considered, where AAAA is 9811da177e4SLinus Torvalds * the area passed down from mprotect_fixup, never extending beyond one 9821da177e4SLinus Torvalds * vma, PPPPPP is the prev vma specified, and NNNNNN the next vma after: 9831da177e4SLinus Torvalds * 9845d42ab29SWei Yang * AAAA AAAA AAAA 9855d42ab29SWei Yang * PPPPPPNNNNNN PPPPPPNNNNNN PPPPPPNNNNNN 9865d42ab29SWei Yang * cannot merge might become might become 9875d42ab29SWei Yang * PPNNNNNNNNNN PPPPPPPPPPNN 9885d42ab29SWei Yang * mmap, brk or case 4 below case 5 below 9895d42ab29SWei Yang * mremap move: 9905d42ab29SWei Yang * AAAA AAAA 9915d42ab29SWei Yang * PPPP NNNN PPPPNNNNXXXX 9925d42ab29SWei Yang * might become might become 9935d42ab29SWei Yang * PPPPPPPPPPPP 1 or PPPPPPPPPPPP 6 or 9945d42ab29SWei Yang * PPPPPPPPNNNN 2 or PPPPPPPPXXXX 7 or 9955d42ab29SWei Yang * PPPPNNNNNNNN 3 PPPPXXXXXXXX 8 9961da177e4SLinus Torvalds * 9978bb4e7a2SWei Yang * It is important for case 8 that the vma NNNN overlapping the 998e86f15eeSAndrea Arcangeli * region AAAA is never going to extended over XXXX. Instead XXXX must 999e86f15eeSAndrea Arcangeli * be extended in region AAAA and NNNN must be removed. This way in 1000e86f15eeSAndrea Arcangeli * all cases where vma_merge succeeds, the moment vma_adjust drops the 1001e86f15eeSAndrea Arcangeli * rmap_locks, the properties of the merged vma will be already 1002e86f15eeSAndrea Arcangeli * correct for the whole merged range. Some of those properties like 1003e86f15eeSAndrea Arcangeli * vm_page_prot/vm_flags may be accessed by rmap_walks and they must 1004e86f15eeSAndrea Arcangeli * be correct for the whole merged range immediately after the 1005e86f15eeSAndrea Arcangeli * rmap_locks are released. Otherwise if XXXX would be removed and 1006e86f15eeSAndrea Arcangeli * NNNN would be extended over the XXXX range, remove_migration_ptes 1007e86f15eeSAndrea Arcangeli * or other rmap walkers (if working on addresses beyond the "end" 1008e86f15eeSAndrea Arcangeli * parameter) may establish ptes with the wrong permissions of NNNN 1009e86f15eeSAndrea Arcangeli * instead of the right permissions of XXXX. 10101da177e4SLinus Torvalds */ 10119760ebffSLiam R. Howlett struct vm_area_struct *vma_merge(struct vma_iterator *vmi, struct mm_struct *mm, 10121da177e4SLinus Torvalds struct vm_area_struct *prev, unsigned long addr, 10131da177e4SLinus Torvalds unsigned long end, unsigned long vm_flags, 10141da177e4SLinus Torvalds struct anon_vma *anon_vma, struct file *file, 101519a809afSAndrea Arcangeli pgoff_t pgoff, struct mempolicy *policy, 10169a10064fSColin Cross struct vm_userfaultfd_ctx vm_userfaultfd_ctx, 10175c26f6acSSuren Baghdasaryan struct anon_vma_name *anon_name) 10181da177e4SLinus Torvalds { 10191da177e4SLinus Torvalds pgoff_t pglen = (end - addr) >> PAGE_SHIFT; 10209760ebffSLiam R. Howlett struct vm_area_struct *mid, *next, *res = NULL; 1021eef19944SJakub Matěna int err = -1; 1022eef19944SJakub Matěna bool merge_prev = false; 1023eef19944SJakub Matěna bool merge_next = false; 10241da177e4SLinus Torvalds 10251da177e4SLinus Torvalds /* 10261da177e4SLinus Torvalds * We later require that vma->vm_flags == vm_flags, 10271da177e4SLinus Torvalds * so this tests vma->vm_flags & VM_SPECIAL, too. 10281da177e4SLinus Torvalds */ 10291da177e4SLinus Torvalds if (vm_flags & VM_SPECIAL) 10301da177e4SLinus Torvalds return NULL; 10311da177e4SLinus Torvalds 1032763ecb03SLiam R. Howlett next = find_vma(mm, prev ? prev->vm_end : 0); 1033eef19944SJakub Matěna mid = next; 1034eef19944SJakub Matěna if (next && next->vm_end == end) /* cases 6, 7, 8 */ 1035763ecb03SLiam R. Howlett next = find_vma(mm, next->vm_end); 10361da177e4SLinus Torvalds 1037e86f15eeSAndrea Arcangeli /* verify some invariant that must be enforced by the caller */ 1038e86f15eeSAndrea Arcangeli VM_WARN_ON(prev && addr <= prev->vm_start); 1039eef19944SJakub Matěna VM_WARN_ON(mid && end > mid->vm_end); 1040e86f15eeSAndrea Arcangeli VM_WARN_ON(addr >= end); 1041e86f15eeSAndrea Arcangeli 1042eef19944SJakub Matěna /* Can we merge the predecessor? */ 10431da177e4SLinus Torvalds if (prev && prev->vm_end == addr && 10441da177e4SLinus Torvalds mpol_equal(vma_policy(prev), policy) && 10451da177e4SLinus Torvalds can_vma_merge_after(prev, vm_flags, 104619a809afSAndrea Arcangeli anon_vma, file, pgoff, 10479a10064fSColin Cross vm_userfaultfd_ctx, anon_name)) { 1048eef19944SJakub Matěna merge_prev = true; 10491da177e4SLinus Torvalds } 1050eef19944SJakub Matěna /* Can we merge the successor? */ 10511da177e4SLinus Torvalds if (next && end == next->vm_start && 10521da177e4SLinus Torvalds mpol_equal(policy, vma_policy(next)) && 10531da177e4SLinus Torvalds can_vma_merge_before(next, vm_flags, 105419a809afSAndrea Arcangeli anon_vma, file, pgoff+pglen, 10559a10064fSColin Cross vm_userfaultfd_ctx, anon_name)) { 1056eef19944SJakub Matěna merge_next = true; 1057eef19944SJakub Matěna } 1058eef19944SJakub Matěna /* Can we merge both the predecessor and the successor? */ 1059eef19944SJakub Matěna if (merge_prev && merge_next && 1060eef19944SJakub Matěna is_mergeable_anon_vma(prev->anon_vma, 1061eef19944SJakub Matěna next->anon_vma, NULL)) { /* cases 1, 6 */ 10629e560446SLiam R. Howlett err = __vma_adjust(vmi, prev, prev->vm_start, 1063eef19944SJakub Matěna next->vm_end, prev->vm_pgoff, NULL, 1064eef19944SJakub Matěna prev); 1065eef19944SJakub Matěna res = prev; 1066eef19944SJakub Matěna } else if (merge_prev) { /* cases 2, 5, 7 */ 10679e560446SLiam R. Howlett err = __vma_adjust(vmi, prev, prev->vm_start, 1068eef19944SJakub Matěna end, prev->vm_pgoff, NULL, prev); 1069eef19944SJakub Matěna res = prev; 1070eef19944SJakub Matěna } else if (merge_next) { 10711da177e4SLinus Torvalds if (prev && addr < prev->vm_end) /* case 4 */ 10729e560446SLiam R. Howlett err = __vma_adjust(vmi, prev, prev->vm_start, 1073e86f15eeSAndrea Arcangeli addr, prev->vm_pgoff, NULL, next); 1074eef19944SJakub Matěna else /* cases 3, 8 */ 10759e560446SLiam R. Howlett err = __vma_adjust(vmi, mid, addr, next->vm_end, 1076e86f15eeSAndrea Arcangeli next->vm_pgoff - pglen, NULL, next); 1077eef19944SJakub Matěna res = next; 10781da177e4SLinus Torvalds } 10791da177e4SLinus Torvalds 1080eef19944SJakub Matěna /* 1081eef19944SJakub Matěna * Cannot merge with predecessor or successor or error in __vma_adjust? 1082eef19944SJakub Matěna */ 1083eef19944SJakub Matěna if (err) 10841da177e4SLinus Torvalds return NULL; 1085eef19944SJakub Matěna khugepaged_enter_vma(res, vm_flags); 10861da177e4SLinus Torvalds 10879760ebffSLiam R. Howlett if (res) 1088f2ebfe43SLiam R. Howlett vma_iter_set(vmi, end); 1089f2ebfe43SLiam R. Howlett 10909760ebffSLiam R. Howlett return res; 1091f2ebfe43SLiam R. Howlett } 1092f2ebfe43SLiam R. Howlett 10931da177e4SLinus Torvalds /* 1094b4f315b4SEthon Paul * Rough compatibility check to quickly see if it's even worth looking 1095d0e9fe17SLinus Torvalds * at sharing an anon_vma. 1096d0e9fe17SLinus Torvalds * 1097d0e9fe17SLinus Torvalds * They need to have the same vm_file, and the flags can only differ 1098d0e9fe17SLinus Torvalds * in things that mprotect may change. 1099d0e9fe17SLinus Torvalds * 1100d0e9fe17SLinus Torvalds * NOTE! The fact that we share an anon_vma doesn't _have_ to mean that 1101d0e9fe17SLinus Torvalds * we can merge the two vma's. For example, we refuse to merge a vma if 1102d0e9fe17SLinus Torvalds * there is a vm_ops->close() function, because that indicates that the 1103d0e9fe17SLinus Torvalds * driver is doing some kind of reference counting. But that doesn't 1104d0e9fe17SLinus Torvalds * really matter for the anon_vma sharing case. 1105d0e9fe17SLinus Torvalds */ 1106d0e9fe17SLinus Torvalds static int anon_vma_compatible(struct vm_area_struct *a, struct vm_area_struct *b) 1107d0e9fe17SLinus Torvalds { 1108d0e9fe17SLinus Torvalds return a->vm_end == b->vm_start && 1109d0e9fe17SLinus Torvalds mpol_equal(vma_policy(a), vma_policy(b)) && 1110d0e9fe17SLinus Torvalds a->vm_file == b->vm_file && 11116cb4d9a2SAnshuman Khandual !((a->vm_flags ^ b->vm_flags) & ~(VM_ACCESS_FLAGS | VM_SOFTDIRTY)) && 1112d0e9fe17SLinus Torvalds b->vm_pgoff == a->vm_pgoff + ((b->vm_start - a->vm_start) >> PAGE_SHIFT); 1113d0e9fe17SLinus Torvalds } 1114d0e9fe17SLinus Torvalds 1115d0e9fe17SLinus Torvalds /* 1116d0e9fe17SLinus Torvalds * Do some basic sanity checking to see if we can re-use the anon_vma 1117d0e9fe17SLinus Torvalds * from 'old'. The 'a'/'b' vma's are in VM order - one of them will be 1118d0e9fe17SLinus Torvalds * the same as 'old', the other will be the new one that is trying 1119d0e9fe17SLinus Torvalds * to share the anon_vma. 1120d0e9fe17SLinus Torvalds * 11215b449489SFlorian Rommel * NOTE! This runs with mmap_lock held for reading, so it is possible that 1122d0e9fe17SLinus Torvalds * the anon_vma of 'old' is concurrently in the process of being set up 1123d0e9fe17SLinus Torvalds * by another page fault trying to merge _that_. But that's ok: if it 1124d0e9fe17SLinus Torvalds * is being set up, that automatically means that it will be a singleton 1125d0e9fe17SLinus Torvalds * acceptable for merging, so we can do all of this optimistically. But 11264db0c3c2SJason Low * we do that READ_ONCE() to make sure that we never re-load the pointer. 1127d0e9fe17SLinus Torvalds * 1128d0e9fe17SLinus Torvalds * IOW: that the "list_is_singular()" test on the anon_vma_chain only 1129d0e9fe17SLinus Torvalds * matters for the 'stable anon_vma' case (ie the thing we want to avoid 1130d0e9fe17SLinus Torvalds * is to return an anon_vma that is "complex" due to having gone through 1131d0e9fe17SLinus Torvalds * a fork). 1132d0e9fe17SLinus Torvalds * 1133d0e9fe17SLinus Torvalds * We also make sure that the two vma's are compatible (adjacent, 1134d0e9fe17SLinus Torvalds * and with the same memory policies). That's all stable, even with just 11355b449489SFlorian Rommel * a read lock on the mmap_lock. 1136d0e9fe17SLinus Torvalds */ 1137d0e9fe17SLinus Torvalds static struct anon_vma *reusable_anon_vma(struct vm_area_struct *old, struct vm_area_struct *a, struct vm_area_struct *b) 1138d0e9fe17SLinus Torvalds { 1139d0e9fe17SLinus Torvalds if (anon_vma_compatible(a, b)) { 11404db0c3c2SJason Low struct anon_vma *anon_vma = READ_ONCE(old->anon_vma); 1141d0e9fe17SLinus Torvalds 1142d0e9fe17SLinus Torvalds if (anon_vma && list_is_singular(&old->anon_vma_chain)) 1143d0e9fe17SLinus Torvalds return anon_vma; 1144d0e9fe17SLinus Torvalds } 1145d0e9fe17SLinus Torvalds return NULL; 1146d0e9fe17SLinus Torvalds } 1147d0e9fe17SLinus Torvalds 1148d0e9fe17SLinus Torvalds /* 11491da177e4SLinus Torvalds * find_mergeable_anon_vma is used by anon_vma_prepare, to check 11501da177e4SLinus Torvalds * neighbouring vmas for a suitable anon_vma, before it goes off 11511da177e4SLinus Torvalds * to allocate a new anon_vma. It checks because a repetitive 11521da177e4SLinus Torvalds * sequence of mprotects and faults may otherwise lead to distinct 11531da177e4SLinus Torvalds * anon_vmas being allocated, preventing vma merge in subsequent 11541da177e4SLinus Torvalds * mprotect. 11551da177e4SLinus Torvalds */ 11561da177e4SLinus Torvalds struct anon_vma *find_mergeable_anon_vma(struct vm_area_struct *vma) 11571da177e4SLinus Torvalds { 1158763ecb03SLiam R. Howlett MA_STATE(mas, &vma->vm_mm->mm_mt, vma->vm_end, vma->vm_end); 1159a67c8caaSMiaohe Lin struct anon_vma *anon_vma = NULL; 1160763ecb03SLiam R. Howlett struct vm_area_struct *prev, *next; 11611da177e4SLinus Torvalds 1162a67c8caaSMiaohe Lin /* Try next first. */ 1163763ecb03SLiam R. Howlett next = mas_walk(&mas); 1164763ecb03SLiam R. Howlett if (next) { 1165763ecb03SLiam R. Howlett anon_vma = reusable_anon_vma(next, vma, next); 1166d0e9fe17SLinus Torvalds if (anon_vma) 1167d0e9fe17SLinus Torvalds return anon_vma; 1168a67c8caaSMiaohe Lin } 11691da177e4SLinus Torvalds 1170763ecb03SLiam R. Howlett prev = mas_prev(&mas, 0); 1171763ecb03SLiam R. Howlett VM_BUG_ON_VMA(prev != vma, vma); 1172763ecb03SLiam R. Howlett prev = mas_prev(&mas, 0); 1173a67c8caaSMiaohe Lin /* Try prev next. */ 1174763ecb03SLiam R. Howlett if (prev) 1175763ecb03SLiam R. Howlett anon_vma = reusable_anon_vma(prev, prev, vma); 1176a67c8caaSMiaohe Lin 11771da177e4SLinus Torvalds /* 1178a67c8caaSMiaohe Lin * We might reach here with anon_vma == NULL if we can't find 1179a67c8caaSMiaohe Lin * any reusable anon_vma. 11801da177e4SLinus Torvalds * There's no absolute need to look only at touching neighbours: 11811da177e4SLinus Torvalds * we could search further afield for "compatible" anon_vmas. 11821da177e4SLinus Torvalds * But it would probably just be a waste of time searching, 11831da177e4SLinus Torvalds * or lead to too many vmas hanging off the same anon_vma. 11841da177e4SLinus Torvalds * We're trying to allow mprotect remerging later on, 11851da177e4SLinus Torvalds * not trying to minimize memory used for anon_vmas. 11861da177e4SLinus Torvalds */ 1187a67c8caaSMiaohe Lin return anon_vma; 11881da177e4SLinus Torvalds } 11891da177e4SLinus Torvalds 11901da177e4SLinus Torvalds /* 119140401530SAl Viro * If a hint addr is less than mmap_min_addr change hint to be as 119240401530SAl Viro * low as possible but still greater than mmap_min_addr 119340401530SAl Viro */ 119440401530SAl Viro static inline unsigned long round_hint_to_min(unsigned long hint) 119540401530SAl Viro { 119640401530SAl Viro hint &= PAGE_MASK; 119740401530SAl Viro if (((void *)hint != NULL) && 119840401530SAl Viro (hint < mmap_min_addr)) 119940401530SAl Viro return PAGE_ALIGN(mmap_min_addr); 120040401530SAl Viro return hint; 120140401530SAl Viro } 120240401530SAl Viro 12036aeb2542SMike Rapoport int mlock_future_check(struct mm_struct *mm, unsigned long flags, 1204363ee17fSDavidlohr Bueso unsigned long len) 1205363ee17fSDavidlohr Bueso { 1206363ee17fSDavidlohr Bueso unsigned long locked, lock_limit; 1207363ee17fSDavidlohr Bueso 1208363ee17fSDavidlohr Bueso /* mlock MCL_FUTURE? */ 1209363ee17fSDavidlohr Bueso if (flags & VM_LOCKED) { 1210363ee17fSDavidlohr Bueso locked = len >> PAGE_SHIFT; 1211363ee17fSDavidlohr Bueso locked += mm->locked_vm; 1212363ee17fSDavidlohr Bueso lock_limit = rlimit(RLIMIT_MEMLOCK); 1213363ee17fSDavidlohr Bueso lock_limit >>= PAGE_SHIFT; 1214363ee17fSDavidlohr Bueso if (locked > lock_limit && !capable(CAP_IPC_LOCK)) 1215363ee17fSDavidlohr Bueso return -EAGAIN; 1216363ee17fSDavidlohr Bueso } 1217363ee17fSDavidlohr Bueso return 0; 1218363ee17fSDavidlohr Bueso } 1219363ee17fSDavidlohr Bueso 1220be83bbf8SLinus Torvalds static inline u64 file_mmap_size_max(struct file *file, struct inode *inode) 1221be83bbf8SLinus Torvalds { 1222be83bbf8SLinus Torvalds if (S_ISREG(inode->i_mode)) 1223423913adSLinus Torvalds return MAX_LFS_FILESIZE; 1224be83bbf8SLinus Torvalds 1225be83bbf8SLinus Torvalds if (S_ISBLK(inode->i_mode)) 1226be83bbf8SLinus Torvalds return MAX_LFS_FILESIZE; 1227be83bbf8SLinus Torvalds 122876f34950SIvan Khoronzhuk if (S_ISSOCK(inode->i_mode)) 122976f34950SIvan Khoronzhuk return MAX_LFS_FILESIZE; 123076f34950SIvan Khoronzhuk 1231be83bbf8SLinus Torvalds /* Special "we do even unsigned file positions" case */ 1232be83bbf8SLinus Torvalds if (file->f_mode & FMODE_UNSIGNED_OFFSET) 1233be83bbf8SLinus Torvalds return 0; 1234be83bbf8SLinus Torvalds 1235be83bbf8SLinus Torvalds /* Yes, random drivers might want more. But I'm tired of buggy drivers */ 1236be83bbf8SLinus Torvalds return ULONG_MAX; 1237be83bbf8SLinus Torvalds } 1238be83bbf8SLinus Torvalds 1239be83bbf8SLinus Torvalds static inline bool file_mmap_ok(struct file *file, struct inode *inode, 1240be83bbf8SLinus Torvalds unsigned long pgoff, unsigned long len) 1241be83bbf8SLinus Torvalds { 1242be83bbf8SLinus Torvalds u64 maxsize = file_mmap_size_max(file, inode); 1243be83bbf8SLinus Torvalds 1244be83bbf8SLinus Torvalds if (maxsize && len > maxsize) 1245be83bbf8SLinus Torvalds return false; 1246be83bbf8SLinus Torvalds maxsize -= len; 1247be83bbf8SLinus Torvalds if (pgoff > maxsize >> PAGE_SHIFT) 1248be83bbf8SLinus Torvalds return false; 1249be83bbf8SLinus Torvalds return true; 1250be83bbf8SLinus Torvalds } 1251be83bbf8SLinus Torvalds 125240401530SAl Viro /* 12533e4e28c5SMichel Lespinasse * The caller must write-lock current->mm->mmap_lock. 12541da177e4SLinus Torvalds */ 12551fcfd8dbSOleg Nesterov unsigned long do_mmap(struct file *file, unsigned long addr, 12561da177e4SLinus Torvalds unsigned long len, unsigned long prot, 125745e55300SPeter Collingbourne unsigned long flags, unsigned long pgoff, 125845e55300SPeter Collingbourne unsigned long *populate, struct list_head *uf) 12591da177e4SLinus Torvalds { 12601da177e4SLinus Torvalds struct mm_struct *mm = current->mm; 126145e55300SPeter Collingbourne vm_flags_t vm_flags; 126262b5f7d0SDave Hansen int pkey = 0; 12631da177e4SLinus Torvalds 1264524e00b3SLiam R. Howlett validate_mm(mm); 126541badc15SMichel Lespinasse *populate = 0; 1266bebeb3d6SMichel Lespinasse 1267e37609bbSPiotr Kwapulinski if (!len) 1268e37609bbSPiotr Kwapulinski return -EINVAL; 1269e37609bbSPiotr Kwapulinski 12701da177e4SLinus Torvalds /* 12711da177e4SLinus Torvalds * Does the application expect PROT_READ to imply PROT_EXEC? 12721da177e4SLinus Torvalds * 12731da177e4SLinus Torvalds * (the exception is when the underlying filesystem is noexec 12741da177e4SLinus Torvalds * mounted, in which case we dont add PROT_EXEC.) 12751da177e4SLinus Torvalds */ 12761da177e4SLinus Torvalds if ((prot & PROT_READ) && (current->personality & READ_IMPLIES_EXEC)) 127790f8572bSEric W. Biederman if (!(file && path_noexec(&file->f_path))) 12781da177e4SLinus Torvalds prot |= PROT_EXEC; 12791da177e4SLinus Torvalds 1280a4ff8e86SMichal Hocko /* force arch specific MAP_FIXED handling in get_unmapped_area */ 1281a4ff8e86SMichal Hocko if (flags & MAP_FIXED_NOREPLACE) 1282a4ff8e86SMichal Hocko flags |= MAP_FIXED; 1283a4ff8e86SMichal Hocko 12847cd94146SEric Paris if (!(flags & MAP_FIXED)) 12857cd94146SEric Paris addr = round_hint_to_min(addr); 12867cd94146SEric Paris 12871da177e4SLinus Torvalds /* Careful about overflows.. */ 12881da177e4SLinus Torvalds len = PAGE_ALIGN(len); 12899206de95SAl Viro if (!len) 12901da177e4SLinus Torvalds return -ENOMEM; 12911da177e4SLinus Torvalds 12921da177e4SLinus Torvalds /* offset overflow? */ 12931da177e4SLinus Torvalds if ((pgoff + (len >> PAGE_SHIFT)) < pgoff) 12941da177e4SLinus Torvalds return -EOVERFLOW; 12951da177e4SLinus Torvalds 12961da177e4SLinus Torvalds /* Too many mappings? */ 12971da177e4SLinus Torvalds if (mm->map_count > sysctl_max_map_count) 12981da177e4SLinus Torvalds return -ENOMEM; 12991da177e4SLinus Torvalds 13001da177e4SLinus Torvalds /* Obtain the address to map to. we verify (or select) it and ensure 13011da177e4SLinus Torvalds * that it represents a valid section of the address space. 13021da177e4SLinus Torvalds */ 13031da177e4SLinus Torvalds addr = get_unmapped_area(file, addr, len, pgoff, flags); 1304ff68dac6SGaowei Pu if (IS_ERR_VALUE(addr)) 13051da177e4SLinus Torvalds return addr; 13061da177e4SLinus Torvalds 1307a4ff8e86SMichal Hocko if (flags & MAP_FIXED_NOREPLACE) { 130835e43c5fSLiam Howlett if (find_vma_intersection(mm, addr, addr + len)) 1309a4ff8e86SMichal Hocko return -EEXIST; 1310a4ff8e86SMichal Hocko } 1311a4ff8e86SMichal Hocko 131262b5f7d0SDave Hansen if (prot == PROT_EXEC) { 131362b5f7d0SDave Hansen pkey = execute_only_pkey(mm); 131462b5f7d0SDave Hansen if (pkey < 0) 131562b5f7d0SDave Hansen pkey = 0; 131662b5f7d0SDave Hansen } 131762b5f7d0SDave Hansen 13181da177e4SLinus Torvalds /* Do simple checking here so the lower-level routines won't have 13191da177e4SLinus Torvalds * to. we assume access permissions have been handled by the open 13201da177e4SLinus Torvalds * of the memory object, so we don't do any here. 13211da177e4SLinus Torvalds */ 132245e55300SPeter Collingbourne vm_flags = calc_vm_prot_bits(prot, pkey) | calc_vm_flag_bits(flags) | 13231da177e4SLinus Torvalds mm->def_flags | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC; 13241da177e4SLinus Torvalds 1325cdf7b341SHuang Shijie if (flags & MAP_LOCKED) 13261da177e4SLinus Torvalds if (!can_do_mlock()) 13271da177e4SLinus Torvalds return -EPERM; 1328ba470de4SRik van Riel 1329363ee17fSDavidlohr Bueso if (mlock_future_check(mm, vm_flags, len)) 13301da177e4SLinus Torvalds return -EAGAIN; 13311da177e4SLinus Torvalds 13321da177e4SLinus Torvalds if (file) { 1333077bf22bSOleg Nesterov struct inode *inode = file_inode(file); 13341c972597SDan Williams unsigned long flags_mask; 13351c972597SDan Williams 1336be83bbf8SLinus Torvalds if (!file_mmap_ok(file, inode, pgoff, len)) 1337be83bbf8SLinus Torvalds return -EOVERFLOW; 1338be83bbf8SLinus Torvalds 13391c972597SDan Williams flags_mask = LEGACY_MAP_MASK | file->f_op->mmap_supported_flags; 1340077bf22bSOleg Nesterov 13411da177e4SLinus Torvalds switch (flags & MAP_TYPE) { 13421da177e4SLinus Torvalds case MAP_SHARED: 13431c972597SDan Williams /* 13441c972597SDan Williams * Force use of MAP_SHARED_VALIDATE with non-legacy 13451c972597SDan Williams * flags. E.g. MAP_SYNC is dangerous to use with 13461c972597SDan Williams * MAP_SHARED as you don't know which consistency model 13471c972597SDan Williams * you will get. We silently ignore unsupported flags 13481c972597SDan Williams * with MAP_SHARED to preserve backward compatibility. 13491c972597SDan Williams */ 13501c972597SDan Williams flags &= LEGACY_MAP_MASK; 1351e4a9bc58SJoe Perches fallthrough; 13521c972597SDan Williams case MAP_SHARED_VALIDATE: 13531c972597SDan Williams if (flags & ~flags_mask) 13541c972597SDan Williams return -EOPNOTSUPP; 1355dc617f29SDarrick J. Wong if (prot & PROT_WRITE) { 1356dc617f29SDarrick J. Wong if (!(file->f_mode & FMODE_WRITE)) 13571da177e4SLinus Torvalds return -EACCES; 1358dc617f29SDarrick J. Wong if (IS_SWAPFILE(file->f_mapping->host)) 1359dc617f29SDarrick J. Wong return -ETXTBSY; 1360dc617f29SDarrick J. Wong } 13611da177e4SLinus Torvalds 13621da177e4SLinus Torvalds /* 13631da177e4SLinus Torvalds * Make sure we don't allow writing to an append-only 13641da177e4SLinus Torvalds * file.. 13651da177e4SLinus Torvalds */ 13661da177e4SLinus Torvalds if (IS_APPEND(inode) && (file->f_mode & FMODE_WRITE)) 13671da177e4SLinus Torvalds return -EACCES; 13681da177e4SLinus Torvalds 13691da177e4SLinus Torvalds vm_flags |= VM_SHARED | VM_MAYSHARE; 13701da177e4SLinus Torvalds if (!(file->f_mode & FMODE_WRITE)) 13711da177e4SLinus Torvalds vm_flags &= ~(VM_MAYWRITE | VM_SHARED); 1372e4a9bc58SJoe Perches fallthrough; 13731da177e4SLinus Torvalds case MAP_PRIVATE: 13741da177e4SLinus Torvalds if (!(file->f_mode & FMODE_READ)) 13751da177e4SLinus Torvalds return -EACCES; 137690f8572bSEric W. Biederman if (path_noexec(&file->f_path)) { 137780c5606cSLinus Torvalds if (vm_flags & VM_EXEC) 137880c5606cSLinus Torvalds return -EPERM; 137980c5606cSLinus Torvalds vm_flags &= ~VM_MAYEXEC; 138080c5606cSLinus Torvalds } 138180c5606cSLinus Torvalds 138272c2d531SAl Viro if (!file->f_op->mmap) 138380c5606cSLinus Torvalds return -ENODEV; 1384b2c56e4fSOleg Nesterov if (vm_flags & (VM_GROWSDOWN|VM_GROWSUP)) 1385b2c56e4fSOleg Nesterov return -EINVAL; 13861da177e4SLinus Torvalds break; 13871da177e4SLinus Torvalds 13881da177e4SLinus Torvalds default: 13891da177e4SLinus Torvalds return -EINVAL; 13901da177e4SLinus Torvalds } 13911da177e4SLinus Torvalds } else { 13921da177e4SLinus Torvalds switch (flags & MAP_TYPE) { 13931da177e4SLinus Torvalds case MAP_SHARED: 1394b2c56e4fSOleg Nesterov if (vm_flags & (VM_GROWSDOWN|VM_GROWSUP)) 1395b2c56e4fSOleg Nesterov return -EINVAL; 1396ce363942STejun Heo /* 1397ce363942STejun Heo * Ignore pgoff. 1398ce363942STejun Heo */ 1399ce363942STejun Heo pgoff = 0; 14001da177e4SLinus Torvalds vm_flags |= VM_SHARED | VM_MAYSHARE; 14011da177e4SLinus Torvalds break; 14021da177e4SLinus Torvalds case MAP_PRIVATE: 14031da177e4SLinus Torvalds /* 14041da177e4SLinus Torvalds * Set pgoff according to addr for anon_vma. 14051da177e4SLinus Torvalds */ 14061da177e4SLinus Torvalds pgoff = addr >> PAGE_SHIFT; 14071da177e4SLinus Torvalds break; 14081da177e4SLinus Torvalds default: 14091da177e4SLinus Torvalds return -EINVAL; 14101da177e4SLinus Torvalds } 14111da177e4SLinus Torvalds } 14121da177e4SLinus Torvalds 1413c22c0d63SMichel Lespinasse /* 1414c22c0d63SMichel Lespinasse * Set 'VM_NORESERVE' if we should not account for the 1415c22c0d63SMichel Lespinasse * memory use of this mapping. 1416c22c0d63SMichel Lespinasse */ 1417c22c0d63SMichel Lespinasse if (flags & MAP_NORESERVE) { 1418c22c0d63SMichel Lespinasse /* We honor MAP_NORESERVE if allowed to overcommit */ 1419c22c0d63SMichel Lespinasse if (sysctl_overcommit_memory != OVERCOMMIT_NEVER) 1420c22c0d63SMichel Lespinasse vm_flags |= VM_NORESERVE; 1421c22c0d63SMichel Lespinasse 1422c22c0d63SMichel Lespinasse /* hugetlb applies strict overcommit unless MAP_NORESERVE */ 1423c22c0d63SMichel Lespinasse if (file && is_file_hugepages(file)) 1424c22c0d63SMichel Lespinasse vm_flags |= VM_NORESERVE; 1425c22c0d63SMichel Lespinasse } 1426c22c0d63SMichel Lespinasse 1427897ab3e0SMike Rapoport addr = mmap_region(file, addr, len, vm_flags, pgoff, uf); 142809a9f1d2SMichel Lespinasse if (!IS_ERR_VALUE(addr) && 142909a9f1d2SMichel Lespinasse ((vm_flags & VM_LOCKED) || 143009a9f1d2SMichel Lespinasse (flags & (MAP_POPULATE | MAP_NONBLOCK)) == MAP_POPULATE)) 143141badc15SMichel Lespinasse *populate = len; 1432bebeb3d6SMichel Lespinasse return addr; 14330165ab44SMiklos Szeredi } 14346be5ceb0SLinus Torvalds 1435a90f590aSDominik Brodowski unsigned long ksys_mmap_pgoff(unsigned long addr, unsigned long len, 1436a90f590aSDominik Brodowski unsigned long prot, unsigned long flags, 1437a90f590aSDominik Brodowski unsigned long fd, unsigned long pgoff) 143866f0dc48SHugh Dickins { 143966f0dc48SHugh Dickins struct file *file = NULL; 14401e3ee14bSChen Gang unsigned long retval; 144166f0dc48SHugh Dickins 144266f0dc48SHugh Dickins if (!(flags & MAP_ANONYMOUS)) { 1443120a795dSAl Viro audit_mmap_fd(fd, flags); 144466f0dc48SHugh Dickins file = fget(fd); 144566f0dc48SHugh Dickins if (!file) 14461e3ee14bSChen Gang return -EBADF; 14477bba8f0eSZhen Lei if (is_file_hugepages(file)) { 1448af73e4d9SNaoya Horiguchi len = ALIGN(len, huge_page_size(hstate_file(file))); 14497bba8f0eSZhen Lei } else if (unlikely(flags & MAP_HUGETLB)) { 1450493af578SJörn Engel retval = -EINVAL; 1451493af578SJörn Engel goto out_fput; 14527bba8f0eSZhen Lei } 145366f0dc48SHugh Dickins } else if (flags & MAP_HUGETLB) { 1454c103a4dcSAndrew Morton struct hstate *hs; 1455af73e4d9SNaoya Horiguchi 145620ac2893SAnshuman Khandual hs = hstate_sizelog((flags >> MAP_HUGE_SHIFT) & MAP_HUGE_MASK); 1457091d0d55SLi Zefan if (!hs) 1458091d0d55SLi Zefan return -EINVAL; 1459091d0d55SLi Zefan 1460091d0d55SLi Zefan len = ALIGN(len, huge_page_size(hs)); 146166f0dc48SHugh Dickins /* 146266f0dc48SHugh Dickins * VM_NORESERVE is used because the reservations will be 146366f0dc48SHugh Dickins * taken when vm_ops->mmap() is called 146466f0dc48SHugh Dickins */ 1465af73e4d9SNaoya Horiguchi file = hugetlb_file_setup(HUGETLB_ANON_FILE, len, 146642d7395fSAndi Kleen VM_NORESERVE, 146783c1fd76Szhangyiru HUGETLB_ANONHUGE_INODE, 146842d7395fSAndi Kleen (flags >> MAP_HUGE_SHIFT) & MAP_HUGE_MASK); 146966f0dc48SHugh Dickins if (IS_ERR(file)) 147066f0dc48SHugh Dickins return PTR_ERR(file); 147166f0dc48SHugh Dickins } 147266f0dc48SHugh Dickins 14739fbeb5abSMichal Hocko retval = vm_mmap_pgoff(file, addr, len, prot, flags, pgoff); 1474493af578SJörn Engel out_fput: 147566f0dc48SHugh Dickins if (file) 147666f0dc48SHugh Dickins fput(file); 147766f0dc48SHugh Dickins return retval; 147866f0dc48SHugh Dickins } 147966f0dc48SHugh Dickins 1480a90f590aSDominik Brodowski SYSCALL_DEFINE6(mmap_pgoff, unsigned long, addr, unsigned long, len, 1481a90f590aSDominik Brodowski unsigned long, prot, unsigned long, flags, 1482a90f590aSDominik Brodowski unsigned long, fd, unsigned long, pgoff) 1483a90f590aSDominik Brodowski { 1484a90f590aSDominik Brodowski return ksys_mmap_pgoff(addr, len, prot, flags, fd, pgoff); 1485a90f590aSDominik Brodowski } 1486a90f590aSDominik Brodowski 1487a4679373SChristoph Hellwig #ifdef __ARCH_WANT_SYS_OLD_MMAP 1488a4679373SChristoph Hellwig struct mmap_arg_struct { 1489a4679373SChristoph Hellwig unsigned long addr; 1490a4679373SChristoph Hellwig unsigned long len; 1491a4679373SChristoph Hellwig unsigned long prot; 1492a4679373SChristoph Hellwig unsigned long flags; 1493a4679373SChristoph Hellwig unsigned long fd; 1494a4679373SChristoph Hellwig unsigned long offset; 1495a4679373SChristoph Hellwig }; 1496a4679373SChristoph Hellwig 1497a4679373SChristoph Hellwig SYSCALL_DEFINE1(old_mmap, struct mmap_arg_struct __user *, arg) 1498a4679373SChristoph Hellwig { 1499a4679373SChristoph Hellwig struct mmap_arg_struct a; 1500a4679373SChristoph Hellwig 1501a4679373SChristoph Hellwig if (copy_from_user(&a, arg, sizeof(a))) 1502a4679373SChristoph Hellwig return -EFAULT; 1503de1741a1SAlexander Kuleshov if (offset_in_page(a.offset)) 1504a4679373SChristoph Hellwig return -EINVAL; 1505a4679373SChristoph Hellwig 1506a90f590aSDominik Brodowski return ksys_mmap_pgoff(a.addr, a.len, a.prot, a.flags, a.fd, 1507a4679373SChristoph Hellwig a.offset >> PAGE_SHIFT); 1508a4679373SChristoph Hellwig } 1509a4679373SChristoph Hellwig #endif /* __ARCH_WANT_SYS_OLD_MMAP */ 1510a4679373SChristoph Hellwig 15114e950f6fSAlexey Dobriyan /* 15128bb4e7a2SWei Yang * Some shared mappings will want the pages marked read-only 15134e950f6fSAlexey Dobriyan * to track write events. If so, we'll downgrade vm_page_prot 15144e950f6fSAlexey Dobriyan * to the private version (using protection_map[] without the 15154e950f6fSAlexey Dobriyan * VM_SHARED bit). 15164e950f6fSAlexey Dobriyan */ 15176d2329f8SAndrea Arcangeli int vma_wants_writenotify(struct vm_area_struct *vma, pgprot_t vm_page_prot) 15184e950f6fSAlexey Dobriyan { 1519ca16d140SKOSAKI Motohiro vm_flags_t vm_flags = vma->vm_flags; 15208a04446aSKirill A. Shutemov const struct vm_operations_struct *vm_ops = vma->vm_ops; 15214e950f6fSAlexey Dobriyan 15224e950f6fSAlexey Dobriyan /* If it was private or non-writable, the write bit is already clear */ 15234e950f6fSAlexey Dobriyan if ((vm_flags & (VM_WRITE|VM_SHARED)) != ((VM_WRITE|VM_SHARED))) 15244e950f6fSAlexey Dobriyan return 0; 15254e950f6fSAlexey Dobriyan 15264e950f6fSAlexey Dobriyan /* The backer wishes to know when pages are first written to? */ 15278a04446aSKirill A. Shutemov if (vm_ops && (vm_ops->page_mkwrite || vm_ops->pfn_mkwrite)) 15284e950f6fSAlexey Dobriyan return 1; 15294e950f6fSAlexey Dobriyan 153064e45507SPeter Feiner /* The open routine did something to the protections that pgprot_modify 153164e45507SPeter Feiner * won't preserve? */ 15326d2329f8SAndrea Arcangeli if (pgprot_val(vm_page_prot) != 15336d2329f8SAndrea Arcangeli pgprot_val(vm_pgprot_modify(vm_page_prot, vm_flags))) 15344e950f6fSAlexey Dobriyan return 0; 15354e950f6fSAlexey Dobriyan 1536f96f7a40SDavid Hildenbrand /* 1537f96f7a40SDavid Hildenbrand * Do we need to track softdirty? hugetlb does not support softdirty 1538f96f7a40SDavid Hildenbrand * tracking yet. 1539f96f7a40SDavid Hildenbrand */ 1540f96f7a40SDavid Hildenbrand if (vma_soft_dirty_enabled(vma) && !is_vm_hugetlb_page(vma)) 154164e45507SPeter Feiner return 1; 154264e45507SPeter Feiner 154351d3d5ebSDavid Hildenbrand /* Do we need write faults for uffd-wp tracking? */ 154451d3d5ebSDavid Hildenbrand if (userfaultfd_wp(vma)) 154551d3d5ebSDavid Hildenbrand return 1; 154651d3d5ebSDavid Hildenbrand 15474e950f6fSAlexey Dobriyan /* Specialty mapping? */ 15484b6e1e37SKonstantin Khlebnikov if (vm_flags & VM_PFNMAP) 15494e950f6fSAlexey Dobriyan return 0; 15504e950f6fSAlexey Dobriyan 15514e950f6fSAlexey Dobriyan /* Can the mapping track the dirty pages? */ 15524e950f6fSAlexey Dobriyan return vma->vm_file && vma->vm_file->f_mapping && 1553f56753acSChristoph Hellwig mapping_can_writeback(vma->vm_file->f_mapping); 15544e950f6fSAlexey Dobriyan } 15554e950f6fSAlexey Dobriyan 1556fc8744adSLinus Torvalds /* 1557fc8744adSLinus Torvalds * We account for memory if it's a private writeable mapping, 15585a6fe125SMel Gorman * not hugepages and VM_NORESERVE wasn't set. 1559fc8744adSLinus Torvalds */ 1560ca16d140SKOSAKI Motohiro static inline int accountable_mapping(struct file *file, vm_flags_t vm_flags) 1561fc8744adSLinus Torvalds { 15625a6fe125SMel Gorman /* 15635a6fe125SMel Gorman * hugetlb has its own accounting separate from the core VM 15645a6fe125SMel Gorman * VM_HUGETLB may not be set yet so we cannot check for that flag. 15655a6fe125SMel Gorman */ 15665a6fe125SMel Gorman if (file && is_file_hugepages(file)) 15675a6fe125SMel Gorman return 0; 15685a6fe125SMel Gorman 1569fc8744adSLinus Torvalds return (vm_flags & (VM_NORESERVE | VM_SHARED | VM_WRITE)) == VM_WRITE; 1570fc8744adSLinus Torvalds } 1571fc8744adSLinus Torvalds 15723499a131SLiam R. Howlett /** 15733499a131SLiam R. Howlett * unmapped_area() - Find an area between the low_limit and the high_limit with 15743499a131SLiam R. Howlett * the correct alignment and offset, all from @info. Note: current->mm is used 15753499a131SLiam R. Howlett * for the search. 15763499a131SLiam R. Howlett * 157782b24936SVernon Yang * @info: The unmapped area information including the range [low_limit - 157882b24936SVernon Yang * high_limit), the alignment offset and mask. 15793499a131SLiam R. Howlett * 15803499a131SLiam R. Howlett * Return: A memory address or -ENOMEM. 15813499a131SLiam R. Howlett */ 1582baceaf1cSJaewon Kim static unsigned long unmapped_area(struct vm_unmapped_area_info *info) 1583db4fbfb9SMichel Lespinasse { 15843499a131SLiam R. Howlett unsigned long length, gap; 1585db4fbfb9SMichel Lespinasse 15863499a131SLiam R. Howlett MA_STATE(mas, ¤t->mm->mm_mt, 0, 0); 1587db4fbfb9SMichel Lespinasse 1588db4fbfb9SMichel Lespinasse /* Adjust search length to account for worst case alignment overhead */ 1589db4fbfb9SMichel Lespinasse length = info->length + info->align_mask; 1590db4fbfb9SMichel Lespinasse if (length < info->length) 1591db4fbfb9SMichel Lespinasse return -ENOMEM; 1592db4fbfb9SMichel Lespinasse 15933499a131SLiam R. Howlett if (mas_empty_area(&mas, info->low_limit, info->high_limit - 1, 15943499a131SLiam R. Howlett length)) 15953499a131SLiam R. Howlett return -ENOMEM; 15963499a131SLiam R. Howlett 1597d4af56c5SLiam R. Howlett gap = mas.index; 1598d4af56c5SLiam R. Howlett gap += (info->align_offset - gap) & info->align_mask; 15993499a131SLiam R. Howlett return gap; 1600db4fbfb9SMichel Lespinasse } 1601db4fbfb9SMichel Lespinasse 16023499a131SLiam R. Howlett /** 16033499a131SLiam R. Howlett * unmapped_area_topdown() - Find an area between the low_limit and the 160482b24936SVernon Yang * high_limit with the correct alignment and offset at the highest available 16053499a131SLiam R. Howlett * address, all from @info. Note: current->mm is used for the search. 16063499a131SLiam R. Howlett * 160782b24936SVernon Yang * @info: The unmapped area information including the range [low_limit - 160882b24936SVernon Yang * high_limit), the alignment offset and mask. 16093499a131SLiam R. Howlett * 16103499a131SLiam R. Howlett * Return: A memory address or -ENOMEM. 16113499a131SLiam R. Howlett */ 1612baceaf1cSJaewon Kim static unsigned long unmapped_area_topdown(struct vm_unmapped_area_info *info) 1613db4fbfb9SMichel Lespinasse { 16143499a131SLiam R. Howlett unsigned long length, gap; 1615d4af56c5SLiam R. Howlett 16163499a131SLiam R. Howlett MA_STATE(mas, ¤t->mm->mm_mt, 0, 0); 1617db4fbfb9SMichel Lespinasse /* Adjust search length to account for worst case alignment overhead */ 1618db4fbfb9SMichel Lespinasse length = info->length + info->align_mask; 1619db4fbfb9SMichel Lespinasse if (length < info->length) 1620db4fbfb9SMichel Lespinasse return -ENOMEM; 1621db4fbfb9SMichel Lespinasse 16223499a131SLiam R. Howlett if (mas_empty_area_rev(&mas, info->low_limit, info->high_limit - 1, 16233499a131SLiam R. Howlett length)) 16243499a131SLiam R. Howlett return -ENOMEM; 16253499a131SLiam R. Howlett 1626d4af56c5SLiam R. Howlett gap = mas.last + 1 - info->length; 1627d4af56c5SLiam R. Howlett gap -= (gap - info->align_offset) & info->align_mask; 16283499a131SLiam R. Howlett return gap; 1629db4fbfb9SMichel Lespinasse } 1630db4fbfb9SMichel Lespinasse 1631baceaf1cSJaewon Kim /* 1632baceaf1cSJaewon Kim * Search for an unmapped address range. 1633baceaf1cSJaewon Kim * 1634baceaf1cSJaewon Kim * We are looking for a range that: 1635baceaf1cSJaewon Kim * - does not intersect with any VMA; 1636baceaf1cSJaewon Kim * - is contained within the [low_limit, high_limit) interval; 1637baceaf1cSJaewon Kim * - is at least the desired size. 1638baceaf1cSJaewon Kim * - satisfies (begin_addr & align_mask) == (align_offset & align_mask) 1639baceaf1cSJaewon Kim */ 1640baceaf1cSJaewon Kim unsigned long vm_unmapped_area(struct vm_unmapped_area_info *info) 1641baceaf1cSJaewon Kim { 1642df529cabSJaewon Kim unsigned long addr; 1643df529cabSJaewon Kim 1644baceaf1cSJaewon Kim if (info->flags & VM_UNMAPPED_AREA_TOPDOWN) 1645df529cabSJaewon Kim addr = unmapped_area_topdown(info); 1646baceaf1cSJaewon Kim else 1647df529cabSJaewon Kim addr = unmapped_area(info); 1648df529cabSJaewon Kim 1649df529cabSJaewon Kim trace_vm_unmapped_area(addr, info); 1650df529cabSJaewon Kim return addr; 1651baceaf1cSJaewon Kim } 1652f6795053SSteve Capper 16531da177e4SLinus Torvalds /* Get an address range which is currently unmapped. 16541da177e4SLinus Torvalds * For shmat() with addr=0. 16551da177e4SLinus Torvalds * 16561da177e4SLinus Torvalds * Ugly calling convention alert: 16571da177e4SLinus Torvalds * Return value with the low bits set means error value, 16581da177e4SLinus Torvalds * ie 16591da177e4SLinus Torvalds * if (ret & ~PAGE_MASK) 16601da177e4SLinus Torvalds * error = ret; 16611da177e4SLinus Torvalds * 16621da177e4SLinus Torvalds * This function "knows" that -ENOMEM has the bits set. 16631da177e4SLinus Torvalds */ 16641da177e4SLinus Torvalds unsigned long 16654b439e25SChristophe Leroy generic_get_unmapped_area(struct file *filp, unsigned long addr, 16664b439e25SChristophe Leroy unsigned long len, unsigned long pgoff, 16674b439e25SChristophe Leroy unsigned long flags) 16681da177e4SLinus Torvalds { 16691da177e4SLinus Torvalds struct mm_struct *mm = current->mm; 16701be7107fSHugh Dickins struct vm_area_struct *vma, *prev; 1671db4fbfb9SMichel Lespinasse struct vm_unmapped_area_info info; 16722cb4de08SChristophe Leroy const unsigned long mmap_end = arch_get_mmap_end(addr, len, flags); 16731da177e4SLinus Torvalds 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 if (addr) { 16811da177e4SLinus Torvalds addr = PAGE_ALIGN(addr); 16821be7107fSHugh Dickins vma = find_vma_prev(mm, addr, &prev); 1683f6795053SSteve Capper if (mmap_end - len >= addr && addr >= mmap_min_addr && 16841be7107fSHugh Dickins (!vma || addr + len <= vm_start_gap(vma)) && 16851be7107fSHugh Dickins (!prev || addr >= vm_end_gap(prev))) 16861da177e4SLinus Torvalds return addr; 16871da177e4SLinus Torvalds } 16881da177e4SLinus Torvalds 1689db4fbfb9SMichel Lespinasse info.flags = 0; 1690db4fbfb9SMichel Lespinasse info.length = len; 16914e99b021SHeiko Carstens info.low_limit = mm->mmap_base; 1692f6795053SSteve Capper info.high_limit = mmap_end; 1693db4fbfb9SMichel Lespinasse info.align_mask = 0; 169409ef5283SJaewon Kim info.align_offset = 0; 1695db4fbfb9SMichel Lespinasse return vm_unmapped_area(&info); 16961da177e4SLinus Torvalds } 16974b439e25SChristophe Leroy 16984b439e25SChristophe Leroy #ifndef HAVE_ARCH_UNMAPPED_AREA 16994b439e25SChristophe Leroy unsigned long 17004b439e25SChristophe Leroy arch_get_unmapped_area(struct file *filp, unsigned long addr, 17014b439e25SChristophe Leroy unsigned long len, unsigned long pgoff, 17024b439e25SChristophe Leroy unsigned long flags) 17034b439e25SChristophe Leroy { 17044b439e25SChristophe Leroy return generic_get_unmapped_area(filp, addr, len, pgoff, flags); 17054b439e25SChristophe Leroy } 17061da177e4SLinus Torvalds #endif 17071da177e4SLinus Torvalds 17081da177e4SLinus Torvalds /* 17091da177e4SLinus Torvalds * This mmap-allocator allocates new areas top-down from below the 17101da177e4SLinus Torvalds * stack's low limit (the base): 17111da177e4SLinus Torvalds */ 17121da177e4SLinus Torvalds unsigned long 17134b439e25SChristophe Leroy generic_get_unmapped_area_topdown(struct file *filp, unsigned long addr, 171443cca0b1SYang Fan unsigned long len, unsigned long pgoff, 171543cca0b1SYang Fan unsigned long flags) 17161da177e4SLinus Torvalds { 17171be7107fSHugh Dickins struct vm_area_struct *vma, *prev; 17181da177e4SLinus Torvalds struct mm_struct *mm = current->mm; 1719db4fbfb9SMichel Lespinasse struct vm_unmapped_area_info info; 17202cb4de08SChristophe Leroy const unsigned long mmap_end = arch_get_mmap_end(addr, len, flags); 17211da177e4SLinus Torvalds 17221da177e4SLinus Torvalds /* requested length too big for entire address space */ 1723f6795053SSteve Capper if (len > mmap_end - mmap_min_addr) 17241da177e4SLinus Torvalds return -ENOMEM; 17251da177e4SLinus Torvalds 172606abdfb4SBenjamin Herrenschmidt if (flags & MAP_FIXED) 172706abdfb4SBenjamin Herrenschmidt return addr; 172806abdfb4SBenjamin Herrenschmidt 17291da177e4SLinus Torvalds /* requesting a specific address */ 17301da177e4SLinus Torvalds if (addr) { 17311da177e4SLinus Torvalds addr = PAGE_ALIGN(addr); 17321be7107fSHugh Dickins vma = find_vma_prev(mm, addr, &prev); 1733f6795053SSteve Capper if (mmap_end - len >= addr && addr >= mmap_min_addr && 17341be7107fSHugh Dickins (!vma || addr + len <= vm_start_gap(vma)) && 17351be7107fSHugh Dickins (!prev || addr >= vm_end_gap(prev))) 17361da177e4SLinus Torvalds return addr; 17371da177e4SLinus Torvalds } 17381da177e4SLinus Torvalds 1739db4fbfb9SMichel Lespinasse info.flags = VM_UNMAPPED_AREA_TOPDOWN; 1740db4fbfb9SMichel Lespinasse info.length = len; 17412afc745fSAkira Takeuchi info.low_limit = max(PAGE_SIZE, mmap_min_addr); 1742f6795053SSteve Capper info.high_limit = arch_get_mmap_base(addr, mm->mmap_base); 1743db4fbfb9SMichel Lespinasse info.align_mask = 0; 174409ef5283SJaewon Kim info.align_offset = 0; 1745db4fbfb9SMichel Lespinasse addr = vm_unmapped_area(&info); 1746b716ad95SXiao Guangrong 17471da177e4SLinus Torvalds /* 17481da177e4SLinus Torvalds * A failed mmap() very likely causes application failure, 17491da177e4SLinus Torvalds * so fall back to the bottom-up function here. This scenario 17501da177e4SLinus Torvalds * can happen with large stack limits and large mmap() 17511da177e4SLinus Torvalds * allocations. 17521da177e4SLinus Torvalds */ 1753de1741a1SAlexander Kuleshov if (offset_in_page(addr)) { 1754db4fbfb9SMichel Lespinasse VM_BUG_ON(addr != -ENOMEM); 1755db4fbfb9SMichel Lespinasse info.flags = 0; 1756db4fbfb9SMichel Lespinasse info.low_limit = TASK_UNMAPPED_BASE; 1757f6795053SSteve Capper info.high_limit = mmap_end; 1758db4fbfb9SMichel Lespinasse addr = vm_unmapped_area(&info); 1759db4fbfb9SMichel Lespinasse } 17601da177e4SLinus Torvalds 17611da177e4SLinus Torvalds return addr; 17621da177e4SLinus Torvalds } 17634b439e25SChristophe Leroy 17644b439e25SChristophe Leroy #ifndef HAVE_ARCH_UNMAPPED_AREA_TOPDOWN 17654b439e25SChristophe Leroy unsigned long 17664b439e25SChristophe Leroy arch_get_unmapped_area_topdown(struct file *filp, unsigned long addr, 17674b439e25SChristophe Leroy unsigned long len, unsigned long pgoff, 17684b439e25SChristophe Leroy unsigned long flags) 17694b439e25SChristophe Leroy { 17704b439e25SChristophe Leroy return generic_get_unmapped_area_topdown(filp, addr, len, pgoff, flags); 17714b439e25SChristophe Leroy } 17721da177e4SLinus Torvalds #endif 17731da177e4SLinus Torvalds 17741da177e4SLinus Torvalds unsigned long 17751da177e4SLinus Torvalds get_unmapped_area(struct file *file, unsigned long addr, unsigned long len, 17761da177e4SLinus Torvalds unsigned long pgoff, unsigned long flags) 17771da177e4SLinus Torvalds { 177806abdfb4SBenjamin Herrenschmidt unsigned long (*get_area)(struct file *, unsigned long, 177906abdfb4SBenjamin Herrenschmidt unsigned long, unsigned long, unsigned long); 178007ab67c8SLinus Torvalds 17819206de95SAl Viro unsigned long error = arch_mmap_check(addr, len, flags); 17829206de95SAl Viro if (error) 17839206de95SAl Viro return error; 17849206de95SAl Viro 17859206de95SAl Viro /* Careful about overflows.. */ 17869206de95SAl Viro if (len > TASK_SIZE) 17879206de95SAl Viro return -ENOMEM; 17889206de95SAl Viro 178907ab67c8SLinus Torvalds get_area = current->mm->get_unmapped_area; 1790c01d5b30SHugh Dickins if (file) { 1791c01d5b30SHugh Dickins if (file->f_op->get_unmapped_area) 179207ab67c8SLinus Torvalds get_area = file->f_op->get_unmapped_area; 1793c01d5b30SHugh Dickins } else if (flags & MAP_SHARED) { 1794c01d5b30SHugh Dickins /* 1795c01d5b30SHugh Dickins * mmap_region() will call shmem_zero_setup() to create a file, 1796c01d5b30SHugh Dickins * so use shmem's get_unmapped_area in case it can be huge. 179745e55300SPeter Collingbourne * do_mmap() will clear pgoff, so match alignment. 1798c01d5b30SHugh Dickins */ 1799c01d5b30SHugh Dickins pgoff = 0; 1800c01d5b30SHugh Dickins get_area = shmem_get_unmapped_area; 1801c01d5b30SHugh Dickins } 1802c01d5b30SHugh Dickins 180307ab67c8SLinus Torvalds addr = get_area(file, addr, len, pgoff, flags); 180407ab67c8SLinus Torvalds if (IS_ERR_VALUE(addr)) 180507ab67c8SLinus Torvalds return addr; 180607ab67c8SLinus Torvalds 18071da177e4SLinus Torvalds if (addr > TASK_SIZE - len) 18081da177e4SLinus Torvalds return -ENOMEM; 1809de1741a1SAlexander Kuleshov if (offset_in_page(addr)) 18101da177e4SLinus Torvalds return -EINVAL; 181106abdfb4SBenjamin Herrenschmidt 18129ac4ed4bSAl Viro error = security_mmap_addr(addr); 18139ac4ed4bSAl Viro return error ? error : addr; 18141da177e4SLinus Torvalds } 18151da177e4SLinus Torvalds 18161da177e4SLinus Torvalds EXPORT_SYMBOL(get_unmapped_area); 18171da177e4SLinus Torvalds 1818be8432e7SLiam R. Howlett /** 1819abdba2ddSLiam R. Howlett * find_vma_intersection() - Look up the first VMA which intersects the interval 1820abdba2ddSLiam R. Howlett * @mm: The process address space. 1821abdba2ddSLiam R. Howlett * @start_addr: The inclusive start user address. 1822abdba2ddSLiam R. Howlett * @end_addr: The exclusive end user address. 1823abdba2ddSLiam R. Howlett * 1824abdba2ddSLiam R. Howlett * Returns: The first VMA within the provided range, %NULL otherwise. Assumes 1825abdba2ddSLiam R. Howlett * start_addr < end_addr. 1826abdba2ddSLiam R. Howlett */ 1827abdba2ddSLiam R. Howlett struct vm_area_struct *find_vma_intersection(struct mm_struct *mm, 1828abdba2ddSLiam R. Howlett unsigned long start_addr, 1829abdba2ddSLiam R. Howlett unsigned long end_addr) 1830abdba2ddSLiam R. Howlett { 1831abdba2ddSLiam R. Howlett unsigned long index = start_addr; 1832abdba2ddSLiam R. Howlett 1833abdba2ddSLiam R. Howlett mmap_assert_locked(mm); 18347964cf8cSLiam R. Howlett return mt_find(&mm->mm_mt, &index, end_addr - 1); 1835abdba2ddSLiam R. Howlett } 1836abdba2ddSLiam R. Howlett EXPORT_SYMBOL(find_vma_intersection); 1837abdba2ddSLiam R. Howlett 1838abdba2ddSLiam R. Howlett /** 1839be8432e7SLiam R. Howlett * find_vma() - Find the VMA for a given address, or the next VMA. 1840be8432e7SLiam R. Howlett * @mm: The mm_struct to check 1841be8432e7SLiam R. Howlett * @addr: The address 1842be8432e7SLiam R. Howlett * 1843be8432e7SLiam R. Howlett * Returns: The VMA associated with addr, or the next VMA. 1844be8432e7SLiam R. Howlett * May return %NULL in the case of no VMA at addr or above. 1845be8432e7SLiam R. Howlett */ 18461da177e4SLinus Torvalds struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr) 18471da177e4SLinus Torvalds { 1848be8432e7SLiam R. Howlett unsigned long index = addr; 18491da177e4SLinus Torvalds 18505b78ed24SLuigi Rizzo mmap_assert_locked(mm); 18517964cf8cSLiam R. Howlett return mt_find(&mm->mm_mt, &index, ULONG_MAX); 18521da177e4SLinus Torvalds } 18531da177e4SLinus Torvalds EXPORT_SYMBOL(find_vma); 18541da177e4SLinus Torvalds 18557fdbd37dSLiam R. Howlett /** 18567fdbd37dSLiam R. Howlett * find_vma_prev() - Find the VMA for a given address, or the next vma and 18577fdbd37dSLiam R. Howlett * set %pprev to the previous VMA, if any. 18587fdbd37dSLiam R. Howlett * @mm: The mm_struct to check 18597fdbd37dSLiam R. Howlett * @addr: The address 18607fdbd37dSLiam R. Howlett * @pprev: The pointer to set to the previous VMA 18617fdbd37dSLiam R. Howlett * 18627fdbd37dSLiam R. Howlett * Note that RCU lock is missing here since the external mmap_lock() is used 18637fdbd37dSLiam R. Howlett * instead. 18647fdbd37dSLiam R. Howlett * 18657fdbd37dSLiam R. Howlett * Returns: The VMA associated with @addr, or the next vma. 18667fdbd37dSLiam R. Howlett * May return %NULL in the case of no vma at addr or above. 18676bd4837dSKOSAKI Motohiro */ 18681da177e4SLinus Torvalds struct vm_area_struct * 18691da177e4SLinus Torvalds find_vma_prev(struct mm_struct *mm, unsigned long addr, 18701da177e4SLinus Torvalds struct vm_area_struct **pprev) 18711da177e4SLinus Torvalds { 18726bd4837dSKOSAKI Motohiro struct vm_area_struct *vma; 18737fdbd37dSLiam R. Howlett MA_STATE(mas, &mm->mm_mt, addr, addr); 18741da177e4SLinus Torvalds 18757fdbd37dSLiam R. Howlett vma = mas_walk(&mas); 18767fdbd37dSLiam R. Howlett *pprev = mas_prev(&mas, 0); 18777fdbd37dSLiam R. Howlett if (!vma) 18787fdbd37dSLiam R. Howlett vma = mas_next(&mas, ULONG_MAX); 18796bd4837dSKOSAKI Motohiro return vma; 18801da177e4SLinus Torvalds } 18811da177e4SLinus Torvalds 18821da177e4SLinus Torvalds /* 18831da177e4SLinus Torvalds * Verify that the stack growth is acceptable and 18841da177e4SLinus Torvalds * update accounting. This is shared with both the 18851da177e4SLinus Torvalds * grow-up and grow-down cases. 18861da177e4SLinus Torvalds */ 18871be7107fSHugh Dickins static int acct_stack_growth(struct vm_area_struct *vma, 18881be7107fSHugh Dickins unsigned long size, unsigned long grow) 18891da177e4SLinus Torvalds { 18901da177e4SLinus Torvalds struct mm_struct *mm = vma->vm_mm; 18911be7107fSHugh Dickins unsigned long new_start; 18921da177e4SLinus Torvalds 18931da177e4SLinus Torvalds /* address space limit tests */ 189484638335SKonstantin Khlebnikov if (!may_expand_vm(mm, vma->vm_flags, grow)) 18951da177e4SLinus Torvalds return -ENOMEM; 18961da177e4SLinus Torvalds 18971da177e4SLinus Torvalds /* Stack limit test */ 189824c79d8eSKrzysztof Opasiak if (size > rlimit(RLIMIT_STACK)) 18991da177e4SLinus Torvalds return -ENOMEM; 19001da177e4SLinus Torvalds 19011da177e4SLinus Torvalds /* mlock limit tests */ 1902c5d8a364SMiaohe Lin if (mlock_future_check(mm, vma->vm_flags, grow << PAGE_SHIFT)) 19031da177e4SLinus Torvalds return -ENOMEM; 19041da177e4SLinus Torvalds 19050d59a01bSAdam Litke /* Check to ensure the stack will not grow into a hugetlb-only region */ 19060d59a01bSAdam Litke new_start = (vma->vm_flags & VM_GROWSUP) ? vma->vm_start : 19070d59a01bSAdam Litke vma->vm_end - size; 19080d59a01bSAdam Litke if (is_hugepage_only_range(vma->vm_mm, new_start, size)) 19090d59a01bSAdam Litke return -EFAULT; 19100d59a01bSAdam Litke 19111da177e4SLinus Torvalds /* 19121da177e4SLinus Torvalds * Overcommit.. This must be the final test, as it will 19131da177e4SLinus Torvalds * update security statistics. 19141da177e4SLinus Torvalds */ 191505fa199dSHugh Dickins if (security_vm_enough_memory_mm(mm, grow)) 19161da177e4SLinus Torvalds return -ENOMEM; 19171da177e4SLinus Torvalds 19181da177e4SLinus Torvalds return 0; 19191da177e4SLinus Torvalds } 19201da177e4SLinus Torvalds 192146dea3d0SHugh Dickins #if defined(CONFIG_STACK_GROWSUP) || defined(CONFIG_IA64) 19221da177e4SLinus Torvalds /* 192346dea3d0SHugh Dickins * PA-RISC uses this for its stack; IA64 for its Register Backing Store. 192446dea3d0SHugh Dickins * vma is the last one with address > vma->vm_end. Have to extend vma. 19251da177e4SLinus Torvalds */ 192646dea3d0SHugh Dickins int expand_upwards(struct vm_area_struct *vma, unsigned long address) 19271da177e4SLinus Torvalds { 192809357814SOleg Nesterov struct mm_struct *mm = vma->vm_mm; 19291be7107fSHugh Dickins struct vm_area_struct *next; 19301be7107fSHugh Dickins unsigned long gap_addr; 193112352d3cSKonstantin Khlebnikov int error = 0; 1932d4af56c5SLiam R. Howlett MA_STATE(mas, &mm->mm_mt, 0, 0); 19331da177e4SLinus Torvalds 19341da177e4SLinus Torvalds if (!(vma->vm_flags & VM_GROWSUP)) 19351da177e4SLinus Torvalds return -EFAULT; 19361da177e4SLinus Torvalds 1937bd726c90SHelge Deller /* Guard against exceeding limits of the address space. */ 19381be7107fSHugh Dickins address &= PAGE_MASK; 193937511fb5SHelge Deller if (address >= (TASK_SIZE & PAGE_MASK)) 194012352d3cSKonstantin Khlebnikov return -ENOMEM; 1941bd726c90SHelge Deller address += PAGE_SIZE; 194212352d3cSKonstantin Khlebnikov 19431be7107fSHugh Dickins /* Enforce stack_guard_gap */ 19441be7107fSHugh Dickins gap_addr = address + stack_guard_gap; 1945bd726c90SHelge Deller 1946bd726c90SHelge Deller /* Guard against overflow */ 1947bd726c90SHelge Deller if (gap_addr < address || gap_addr > TASK_SIZE) 1948bd726c90SHelge Deller gap_addr = TASK_SIZE; 1949bd726c90SHelge Deller 1950763ecb03SLiam R. Howlett next = find_vma_intersection(mm, vma->vm_end, gap_addr); 1951763ecb03SLiam R. Howlett if (next && vma_is_accessible(next)) { 19521be7107fSHugh Dickins if (!(next->vm_flags & VM_GROWSUP)) 19531be7107fSHugh Dickins return -ENOMEM; 19541be7107fSHugh Dickins /* Check that both stack segments have the same anon_vma? */ 19551be7107fSHugh Dickins } 19561be7107fSHugh Dickins 1957c5d5546eSVernon Yang if (mas_preallocate(&mas, GFP_KERNEL)) 19581da177e4SLinus Torvalds return -ENOMEM; 19591da177e4SLinus Torvalds 1960d4af56c5SLiam R. Howlett /* We must make sure the anon_vma is allocated. */ 1961d4af56c5SLiam R. Howlett if (unlikely(anon_vma_prepare(vma))) { 1962d4af56c5SLiam R. Howlett mas_destroy(&mas); 1963d4af56c5SLiam R. Howlett return -ENOMEM; 1964d4af56c5SLiam R. Howlett } 1965d4af56c5SLiam R. Howlett 19661da177e4SLinus Torvalds /* 19671da177e4SLinus Torvalds * vma->vm_start/vm_end cannot change under us because the caller 1968c1e8d7c6SMichel Lespinasse * is required to hold the mmap_lock in read mode. We need the 19691da177e4SLinus Torvalds * anon_vma lock to serialize against concurrent expand_stacks. 19701da177e4SLinus Torvalds */ 197112352d3cSKonstantin Khlebnikov anon_vma_lock_write(vma->anon_vma); 19721da177e4SLinus Torvalds 19731da177e4SLinus Torvalds /* Somebody else might have raced and expanded it already */ 19741da177e4SLinus Torvalds if (address > vma->vm_end) { 19751da177e4SLinus Torvalds unsigned long size, grow; 19761da177e4SLinus Torvalds 19771da177e4SLinus Torvalds size = address - vma->vm_start; 19781da177e4SLinus Torvalds grow = (address - vma->vm_end) >> PAGE_SHIFT; 19791da177e4SLinus Torvalds 198042c36f63SHugh Dickins error = -ENOMEM; 198142c36f63SHugh Dickins if (vma->vm_pgoff + (size >> PAGE_SHIFT) >= vma->vm_pgoff) { 19821da177e4SLinus Torvalds error = acct_stack_growth(vma, size, grow); 19833af9e859SEric B Munson if (!error) { 19844128997bSMichel Lespinasse /* 1985524e00b3SLiam R. Howlett * We only hold a shared mmap_lock lock here, so 1986524e00b3SLiam R. Howlett * we need to protect against concurrent vma 1987524e00b3SLiam R. Howlett * expansions. anon_vma_lock_write() doesn't 1988524e00b3SLiam R. Howlett * help here, as we don't guarantee that all 1989524e00b3SLiam R. Howlett * growable vmas in a mm share the same root 1990524e00b3SLiam R. Howlett * anon vma. So, we reuse mm->page_table_lock 1991524e00b3SLiam R. Howlett * to guard against concurrent vma expansions. 19924128997bSMichel Lespinasse */ 199309357814SOleg Nesterov spin_lock(&mm->page_table_lock); 199487e8827bSOleg Nesterov if (vma->vm_flags & VM_LOCKED) 199509357814SOleg Nesterov mm->locked_vm += grow; 199684638335SKonstantin Khlebnikov vm_stat_account(mm, vma->vm_flags, grow); 1997bf181b9fSMichel Lespinasse anon_vma_interval_tree_pre_update_vma(vma); 19981da177e4SLinus Torvalds vma->vm_end = address; 1999d4af56c5SLiam R. Howlett /* Overwrite old entry in mtree. */ 2000fbcc3104SLiam R. Howlett mas_set_range(&mas, vma->vm_start, address - 1); 2001fbcc3104SLiam R. Howlett mas_store_prealloc(&mas, vma); 2002bf181b9fSMichel Lespinasse anon_vma_interval_tree_post_update_vma(vma); 200309357814SOleg Nesterov spin_unlock(&mm->page_table_lock); 20044128997bSMichel Lespinasse 20053af9e859SEric B Munson perf_event_mmap(vma); 20063af9e859SEric B Munson } 20071da177e4SLinus Torvalds } 200842c36f63SHugh Dickins } 200912352d3cSKonstantin Khlebnikov anon_vma_unlock_write(vma->anon_vma); 2010c791576cSYang Shi khugepaged_enter_vma(vma, vma->vm_flags); 2011d4af56c5SLiam R. Howlett mas_destroy(&mas); 20121da177e4SLinus Torvalds return error; 20131da177e4SLinus Torvalds } 201446dea3d0SHugh Dickins #endif /* CONFIG_STACK_GROWSUP || CONFIG_IA64 */ 201546dea3d0SHugh Dickins 20161da177e4SLinus Torvalds /* 20171da177e4SLinus Torvalds * vma is the first one with address < vma->vm_start. Have to extend vma. 20181da177e4SLinus Torvalds */ 2019524e00b3SLiam R. Howlett int expand_downwards(struct vm_area_struct *vma, unsigned long address) 20201da177e4SLinus Torvalds { 202109357814SOleg Nesterov struct mm_struct *mm = vma->vm_mm; 2022763ecb03SLiam R. Howlett MA_STATE(mas, &mm->mm_mt, vma->vm_start, vma->vm_start); 20231be7107fSHugh Dickins struct vm_area_struct *prev; 20240a1d5299SJann Horn int error = 0; 20251da177e4SLinus Torvalds 20268869477aSEric Paris address &= PAGE_MASK; 20270a1d5299SJann Horn if (address < mmap_min_addr) 20280a1d5299SJann Horn return -EPERM; 20298869477aSEric Paris 20301be7107fSHugh Dickins /* Enforce stack_guard_gap */ 2031763ecb03SLiam R. Howlett prev = mas_prev(&mas, 0); 20321be7107fSHugh Dickins /* Check that both stack segments have the same anon_vma? */ 203332e4e6d5SOleg Nesterov if (prev && !(prev->vm_flags & VM_GROWSDOWN) && 20343122e80eSAnshuman Khandual vma_is_accessible(prev)) { 203532e4e6d5SOleg Nesterov if (address - prev->vm_end < stack_guard_gap) 203632e4e6d5SOleg Nesterov return -ENOMEM; 20371be7107fSHugh Dickins } 20381be7107fSHugh Dickins 2039c5d5546eSVernon Yang if (mas_preallocate(&mas, GFP_KERNEL)) 204012352d3cSKonstantin Khlebnikov return -ENOMEM; 20411da177e4SLinus Torvalds 2042d4af56c5SLiam R. Howlett /* We must make sure the anon_vma is allocated. */ 2043d4af56c5SLiam R. Howlett if (unlikely(anon_vma_prepare(vma))) { 2044d4af56c5SLiam R. Howlett mas_destroy(&mas); 2045d4af56c5SLiam R. Howlett return -ENOMEM; 2046d4af56c5SLiam R. Howlett } 2047d4af56c5SLiam R. Howlett 20481da177e4SLinus Torvalds /* 20491da177e4SLinus Torvalds * vma->vm_start/vm_end cannot change under us because the caller 2050c1e8d7c6SMichel Lespinasse * is required to hold the mmap_lock in read mode. We need the 20511da177e4SLinus Torvalds * anon_vma lock to serialize against concurrent expand_stacks. 20521da177e4SLinus Torvalds */ 205312352d3cSKonstantin Khlebnikov anon_vma_lock_write(vma->anon_vma); 20541da177e4SLinus Torvalds 20551da177e4SLinus Torvalds /* Somebody else might have raced and expanded it already */ 20561da177e4SLinus Torvalds if (address < vma->vm_start) { 20571da177e4SLinus Torvalds unsigned long size, grow; 20581da177e4SLinus Torvalds 20591da177e4SLinus Torvalds size = vma->vm_end - address; 20601da177e4SLinus Torvalds grow = (vma->vm_start - address) >> PAGE_SHIFT; 20611da177e4SLinus Torvalds 2062a626ca6aSLinus Torvalds error = -ENOMEM; 2063a626ca6aSLinus Torvalds if (grow <= vma->vm_pgoff) { 20641da177e4SLinus Torvalds error = acct_stack_growth(vma, size, grow); 20651da177e4SLinus Torvalds if (!error) { 20664128997bSMichel Lespinasse /* 2067524e00b3SLiam R. Howlett * We only hold a shared mmap_lock lock here, so 2068524e00b3SLiam R. Howlett * we need to protect against concurrent vma 2069524e00b3SLiam R. Howlett * expansions. anon_vma_lock_write() doesn't 2070524e00b3SLiam R. Howlett * help here, as we don't guarantee that all 2071524e00b3SLiam R. Howlett * growable vmas in a mm share the same root 2072524e00b3SLiam R. Howlett * anon vma. So, we reuse mm->page_table_lock 2073524e00b3SLiam R. Howlett * to guard against concurrent vma expansions. 20744128997bSMichel Lespinasse */ 207509357814SOleg Nesterov spin_lock(&mm->page_table_lock); 207687e8827bSOleg Nesterov if (vma->vm_flags & VM_LOCKED) 207709357814SOleg Nesterov mm->locked_vm += grow; 207884638335SKonstantin Khlebnikov vm_stat_account(mm, vma->vm_flags, grow); 2079bf181b9fSMichel Lespinasse anon_vma_interval_tree_pre_update_vma(vma); 20801da177e4SLinus Torvalds vma->vm_start = address; 20811da177e4SLinus Torvalds vma->vm_pgoff -= grow; 2082d4af56c5SLiam R. Howlett /* Overwrite old entry in mtree. */ 2083fbcc3104SLiam R. Howlett mas_set_range(&mas, address, vma->vm_end - 1); 2084fbcc3104SLiam R. Howlett mas_store_prealloc(&mas, vma); 2085bf181b9fSMichel Lespinasse anon_vma_interval_tree_post_update_vma(vma); 208609357814SOleg Nesterov spin_unlock(&mm->page_table_lock); 20874128997bSMichel Lespinasse 20883af9e859SEric B Munson perf_event_mmap(vma); 20891da177e4SLinus Torvalds } 20901da177e4SLinus Torvalds } 2091a626ca6aSLinus Torvalds } 209212352d3cSKonstantin Khlebnikov anon_vma_unlock_write(vma->anon_vma); 2093c791576cSYang Shi khugepaged_enter_vma(vma, vma->vm_flags); 2094d4af56c5SLiam R. Howlett mas_destroy(&mas); 20951da177e4SLinus Torvalds return error; 20961da177e4SLinus Torvalds } 20971da177e4SLinus Torvalds 20981be7107fSHugh Dickins /* enforced gap between the expanding stack and other mappings. */ 20991be7107fSHugh Dickins unsigned long stack_guard_gap = 256UL<<PAGE_SHIFT; 21001be7107fSHugh Dickins 21011be7107fSHugh Dickins static int __init cmdline_parse_stack_guard_gap(char *p) 21021be7107fSHugh Dickins { 21031be7107fSHugh Dickins unsigned long val; 21041be7107fSHugh Dickins char *endptr; 21051be7107fSHugh Dickins 21061be7107fSHugh Dickins val = simple_strtoul(p, &endptr, 10); 21071be7107fSHugh Dickins if (!*endptr) 21081be7107fSHugh Dickins stack_guard_gap = val << PAGE_SHIFT; 21091be7107fSHugh Dickins 2110e6d09493SRandy Dunlap return 1; 21111be7107fSHugh Dickins } 21121be7107fSHugh Dickins __setup("stack_guard_gap=", cmdline_parse_stack_guard_gap); 21131be7107fSHugh Dickins 2114b6a2fea3SOllie Wild #ifdef CONFIG_STACK_GROWSUP 2115b6a2fea3SOllie Wild int expand_stack(struct vm_area_struct *vma, unsigned long address) 2116b6a2fea3SOllie Wild { 2117b6a2fea3SOllie Wild return expand_upwards(vma, address); 2118b6a2fea3SOllie Wild } 2119b6a2fea3SOllie Wild 2120b6a2fea3SOllie Wild struct vm_area_struct * 2121b6a2fea3SOllie Wild find_extend_vma(struct mm_struct *mm, unsigned long addr) 2122b6a2fea3SOllie Wild { 2123b6a2fea3SOllie Wild struct vm_area_struct *vma, *prev; 2124b6a2fea3SOllie Wild 2125b6a2fea3SOllie Wild addr &= PAGE_MASK; 2126b6a2fea3SOllie Wild vma = find_vma_prev(mm, addr, &prev); 2127b6a2fea3SOllie Wild if (vma && (vma->vm_start <= addr)) 2128b6a2fea3SOllie Wild return vma; 21294d45e75aSJann Horn if (!prev || expand_stack(prev, addr)) 2130b6a2fea3SOllie Wild return NULL; 2131cea10a19SMichel Lespinasse if (prev->vm_flags & VM_LOCKED) 2132fc05f566SKirill A. Shutemov populate_vma_page_range(prev, addr, prev->vm_end, NULL); 2133b6a2fea3SOllie Wild return prev; 2134b6a2fea3SOllie Wild } 2135b6a2fea3SOllie Wild #else 2136b6a2fea3SOllie Wild int expand_stack(struct vm_area_struct *vma, unsigned long address) 2137b6a2fea3SOllie Wild { 2138b6a2fea3SOllie Wild return expand_downwards(vma, address); 2139b6a2fea3SOllie Wild } 2140b6a2fea3SOllie Wild 21411da177e4SLinus Torvalds struct vm_area_struct * 21421da177e4SLinus Torvalds find_extend_vma(struct mm_struct *mm, unsigned long addr) 21431da177e4SLinus Torvalds { 21441da177e4SLinus Torvalds struct vm_area_struct *vma; 21451da177e4SLinus Torvalds unsigned long start; 21461da177e4SLinus Torvalds 21471da177e4SLinus Torvalds addr &= PAGE_MASK; 21481da177e4SLinus Torvalds vma = find_vma(mm, addr); 21491da177e4SLinus Torvalds if (!vma) 21501da177e4SLinus Torvalds return NULL; 21511da177e4SLinus Torvalds if (vma->vm_start <= addr) 21521da177e4SLinus Torvalds return vma; 21531da177e4SLinus Torvalds if (!(vma->vm_flags & VM_GROWSDOWN)) 21541da177e4SLinus Torvalds return NULL; 21551da177e4SLinus Torvalds start = vma->vm_start; 21561da177e4SLinus Torvalds if (expand_stack(vma, addr)) 21571da177e4SLinus Torvalds return NULL; 2158cea10a19SMichel Lespinasse if (vma->vm_flags & VM_LOCKED) 2159fc05f566SKirill A. Shutemov populate_vma_page_range(vma, addr, start, NULL); 21601da177e4SLinus Torvalds return vma; 21611da177e4SLinus Torvalds } 21621da177e4SLinus Torvalds #endif 21631da177e4SLinus Torvalds 2164e1d6d01aSJesse Barnes EXPORT_SYMBOL_GPL(find_extend_vma); 2165e1d6d01aSJesse Barnes 21662c0b3814SHugh Dickins /* 2167763ecb03SLiam R. Howlett * Ok - we have the memory areas we should free on a maple tree so release them, 2168763ecb03SLiam R. Howlett * and do the vma updates. 21691da177e4SLinus Torvalds * 21702c0b3814SHugh Dickins * Called with the mm semaphore held. 21711da177e4SLinus Torvalds */ 2172763ecb03SLiam R. Howlett static inline void remove_mt(struct mm_struct *mm, struct ma_state *mas) 21731da177e4SLinus Torvalds { 21744f74d2c8SLinus Torvalds unsigned long nr_accounted = 0; 2175763ecb03SLiam R. Howlett struct vm_area_struct *vma; 21764f74d2c8SLinus Torvalds 2177365e9c87SHugh Dickins /* Update high watermark before we lower total_vm */ 2178365e9c87SHugh Dickins update_hiwater_vm(mm); 2179763ecb03SLiam R. Howlett mas_for_each(mas, vma, ULONG_MAX) { 2180ab50b8edSHugh Dickins long nrpages = vma_pages(vma); 21811da177e4SLinus Torvalds 21824f74d2c8SLinus Torvalds if (vma->vm_flags & VM_ACCOUNT) 21834f74d2c8SLinus Torvalds nr_accounted += nrpages; 218484638335SKonstantin Khlebnikov vm_stat_account(mm, vma->vm_flags, -nrpages); 2185763ecb03SLiam R. Howlett remove_vma(vma); 2186763ecb03SLiam R. Howlett } 21874f74d2c8SLinus Torvalds vm_unacct_memory(nr_accounted); 21881da177e4SLinus Torvalds validate_mm(mm); 21891da177e4SLinus Torvalds } 21901da177e4SLinus Torvalds 21911da177e4SLinus Torvalds /* 21921da177e4SLinus Torvalds * Get rid of page table information in the indicated region. 21931da177e4SLinus Torvalds * 2194f10df686SPaolo 'Blaisorblade' Giarrusso * Called with the mm semaphore held. 21951da177e4SLinus Torvalds */ 2196763ecb03SLiam R. Howlett static void unmap_region(struct mm_struct *mm, struct maple_tree *mt, 2197e0da382cSHugh Dickins struct vm_area_struct *vma, struct vm_area_struct *prev, 2198763ecb03SLiam R. Howlett struct vm_area_struct *next, 2199e0da382cSHugh Dickins unsigned long start, unsigned long end) 22001da177e4SLinus Torvalds { 2201d16dfc55SPeter Zijlstra struct mmu_gather tlb; 22021da177e4SLinus Torvalds 22031da177e4SLinus Torvalds lru_add_drain(); 2204a72afd87SWill Deacon tlb_gather_mmu(&tlb, mm); 2205365e9c87SHugh Dickins update_hiwater_rss(mm); 2206763ecb03SLiam R. Howlett unmap_vmas(&tlb, mt, vma, start, end); 2207763ecb03SLiam R. Howlett free_pgtables(&tlb, mt, vma, prev ? prev->vm_end : FIRST_USER_ADDRESS, 22086ee8630eSHugh Dickins next ? next->vm_start : USER_PGTABLES_CEILING); 2209ae8eba8bSWill Deacon tlb_finish_mmu(&tlb); 22101da177e4SLinus Torvalds } 22111da177e4SLinus Torvalds 22121da177e4SLinus Torvalds /* 2213def5efe0SDavid Rientjes * __split_vma() bypasses sysctl_max_map_count checking. We use this where it 2214def5efe0SDavid Rientjes * has already been checked or doesn't make sense to fail. 22150fd5a9e2SLiam R. Howlett * VMA Iterator will point to the end VMA. 22161da177e4SLinus Torvalds */ 22179760ebffSLiam R. Howlett int __split_vma(struct vma_iterator *vmi, struct vm_area_struct *vma, 22181da177e4SLinus Torvalds unsigned long addr, int new_below) 22191da177e4SLinus Torvalds { 22201da177e4SLinus Torvalds struct vm_area_struct *new; 2221e3975891SChen Gang int err; 22229760ebffSLiam R. Howlett 22239760ebffSLiam R. Howlett validate_mm_mt(vma->vm_mm); 22241da177e4SLinus Torvalds 2225dd3b614fSDmitry Safonov if (vma->vm_ops && vma->vm_ops->may_split) { 2226dd3b614fSDmitry Safonov err = vma->vm_ops->may_split(vma, addr); 222731383c68SDan Williams if (err) 222831383c68SDan Williams return err; 222931383c68SDan Williams } 22301da177e4SLinus Torvalds 22313928d4f5SLinus Torvalds new = vm_area_dup(vma); 22321da177e4SLinus Torvalds if (!new) 2233e3975891SChen Gang return -ENOMEM; 22341da177e4SLinus Torvalds 22351da177e4SLinus Torvalds if (new_below) 22361da177e4SLinus Torvalds new->vm_end = addr; 22371da177e4SLinus Torvalds else { 22381da177e4SLinus Torvalds new->vm_start = addr; 22391da177e4SLinus Torvalds new->vm_pgoff += ((addr - vma->vm_start) >> PAGE_SHIFT); 22401da177e4SLinus Torvalds } 22411da177e4SLinus Torvalds 2242ef0855d3SOleg Nesterov err = vma_dup_policy(vma, new); 2243ef0855d3SOleg Nesterov if (err) 22445beb4930SRik van Riel goto out_free_vma; 22451da177e4SLinus Torvalds 2246c4ea95d7SDaniel Forrest err = anon_vma_clone(new, vma); 2247c4ea95d7SDaniel Forrest if (err) 22485beb4930SRik van Riel goto out_free_mpol; 22495beb4930SRik van Riel 2250e9714acfSKonstantin Khlebnikov if (new->vm_file) 22511da177e4SLinus Torvalds get_file(new->vm_file); 22521da177e4SLinus Torvalds 22531da177e4SLinus Torvalds if (new->vm_ops && new->vm_ops->open) 22541da177e4SLinus Torvalds new->vm_ops->open(new); 22551da177e4SLinus Torvalds 22561da177e4SLinus Torvalds if (new_below) 2257b373037fSLiam R. Howlett err = vma_adjust(vmi, vma, addr, vma->vm_end, 22580fd5a9e2SLiam R. Howlett vma->vm_pgoff + ((addr - new->vm_start) >> PAGE_SHIFT), 2259b373037fSLiam R. Howlett new); 22601da177e4SLinus Torvalds else 2261b373037fSLiam R. Howlett err = vma_adjust(vmi, vma, vma->vm_start, addr, vma->vm_pgoff, 2262b373037fSLiam R. Howlett new); 22631da177e4SLinus Torvalds 22645beb4930SRik van Riel /* Success. */ 22659760ebffSLiam R. Howlett if (!err) { 22660fd5a9e2SLiam R. Howlett if (new_below) 22670fd5a9e2SLiam R. Howlett vma_next(vmi); 22681da177e4SLinus Torvalds return 0; 22699760ebffSLiam R. Howlett } 22705beb4930SRik van Riel 2271d4af56c5SLiam R. Howlett /* Avoid vm accounting in close() operation */ 2272d4af56c5SLiam R. Howlett new->vm_start = new->vm_end; 2273d4af56c5SLiam R. Howlett new->vm_pgoff = 0; 22745beb4930SRik van Riel /* Clean everything up if vma_adjust failed. */ 227558927533SRik van Riel if (new->vm_ops && new->vm_ops->close) 22765beb4930SRik van Riel new->vm_ops->close(new); 2277e9714acfSKonstantin Khlebnikov if (new->vm_file) 22785beb4930SRik van Riel fput(new->vm_file); 22792aeadc30SAndrea Arcangeli unlink_anon_vmas(new); 22805beb4930SRik van Riel out_free_mpol: 2281ef0855d3SOleg Nesterov mpol_put(vma_policy(new)); 22825beb4930SRik van Riel out_free_vma: 22833928d4f5SLinus Torvalds vm_area_free(new); 22849760ebffSLiam R. Howlett validate_mm_mt(vma->vm_mm); 22855beb4930SRik van Riel return err; 22861da177e4SLinus Torvalds } 22871da177e4SLinus Torvalds 2288659ace58SKOSAKI Motohiro /* 2289659ace58SKOSAKI Motohiro * Split a vma into two pieces at address 'addr', a new vma is allocated 2290659ace58SKOSAKI Motohiro * either for the first part or the tail. 2291659ace58SKOSAKI Motohiro */ 22929760ebffSLiam R. Howlett int split_vma(struct vma_iterator *vmi, struct vm_area_struct *vma, 2293659ace58SKOSAKI Motohiro unsigned long addr, int new_below) 2294659ace58SKOSAKI Motohiro { 22959760ebffSLiam R. Howlett if (vma->vm_mm->map_count >= sysctl_max_map_count) 2296659ace58SKOSAKI Motohiro return -ENOMEM; 2297659ace58SKOSAKI Motohiro 22989760ebffSLiam R. Howlett return __split_vma(vmi, vma, addr, new_below); 2299f2ebfe43SLiam R. Howlett } 2300f2ebfe43SLiam R. Howlett 2301763ecb03SLiam R. Howlett static inline int munmap_sidetree(struct vm_area_struct *vma, 2302763ecb03SLiam R. Howlett struct ma_state *mas_detach) 23031da177e4SLinus Torvalds { 2304763ecb03SLiam R. Howlett mas_set_range(mas_detach, vma->vm_start, vma->vm_end - 1); 2305763ecb03SLiam R. Howlett if (mas_store_gfp(mas_detach, vma, GFP_KERNEL)) 2306763ecb03SLiam R. Howlett return -ENOMEM; 230711f9a21aSLiam R. Howlett 2308763ecb03SLiam R. Howlett if (vma->vm_flags & VM_LOCKED) 2309763ecb03SLiam R. Howlett vma->vm_mm->locked_vm -= vma_pages(vma); 231011f9a21aSLiam R. Howlett 2311763ecb03SLiam R. Howlett return 0; 231211f9a21aSLiam R. Howlett } 231311f9a21aSLiam R. Howlett 231411f9a21aSLiam R. Howlett /* 2315183654ceSLiam R. Howlett * do_vmi_align_munmap() - munmap the aligned region from @start to @end. 2316183654ceSLiam R. Howlett * @vmi: The vma iterator 231711f9a21aSLiam R. Howlett * @vma: The starting vm_area_struct 231811f9a21aSLiam R. Howlett * @mm: The mm_struct 231911f9a21aSLiam R. Howlett * @start: The aligned start address to munmap. 232011f9a21aSLiam R. Howlett * @end: The aligned end address to munmap. 232111f9a21aSLiam R. Howlett * @uf: The userfaultfd list_head 23228651a137SLorenzo Stoakes * @downgrade: Set to true to attempt a write downgrade of the mmap_lock 232311f9a21aSLiam R. Howlett * 232411f9a21aSLiam R. Howlett * If @downgrade is true, check return code for potential release of the lock. 232511f9a21aSLiam R. Howlett */ 232611f9a21aSLiam R. Howlett static int 2327183654ceSLiam R. Howlett do_vmi_align_munmap(struct vma_iterator *vmi, struct vm_area_struct *vma, 232811f9a21aSLiam R. Howlett struct mm_struct *mm, unsigned long start, 232911f9a21aSLiam R. Howlett unsigned long end, struct list_head *uf, bool downgrade) 233011f9a21aSLiam R. Howlett { 2331763ecb03SLiam R. Howlett struct vm_area_struct *prev, *next = NULL; 2332763ecb03SLiam R. Howlett struct maple_tree mt_detach; 2333763ecb03SLiam R. Howlett int count = 0; 2334d4af56c5SLiam R. Howlett int error = -ENOMEM; 2335763ecb03SLiam R. Howlett MA_STATE(mas_detach, &mt_detach, 0, 0); 2336763ecb03SLiam R. Howlett mt_init_flags(&mt_detach, MT_FLAGS_LOCK_EXTERN); 2337763ecb03SLiam R. Howlett mt_set_external_lock(&mt_detach, &mm->mmap_lock); 2338524e00b3SLiam R. Howlett 23391da177e4SLinus Torvalds /* 23401da177e4SLinus Torvalds * If we need to split any vma, do it now to save pain later. 23411da177e4SLinus Torvalds * 23421da177e4SLinus Torvalds * Note: mremap's move_vma VM_ACCOUNT handling assumes a partially 23431da177e4SLinus Torvalds * unmapped vm_area_struct will remain in use: so lower split_vma 23441da177e4SLinus Torvalds * places tmp vma above, and higher split_vma places tmp vma below. 23451da177e4SLinus Torvalds */ 2346763ecb03SLiam R. Howlett 2347763ecb03SLiam R. Howlett /* Does it split the first one? */ 2348146425a3SHugh Dickins if (start > vma->vm_start) { 2349659ace58SKOSAKI Motohiro 2350659ace58SKOSAKI Motohiro /* 2351659ace58SKOSAKI Motohiro * Make sure that map_count on return from munmap() will 2352659ace58SKOSAKI Motohiro * not exceed its limit; but let map_count go just above 2353659ace58SKOSAKI Motohiro * its limit temporarily, to help free resources as expected. 2354659ace58SKOSAKI Motohiro */ 2355659ace58SKOSAKI Motohiro if (end < vma->vm_end && mm->map_count >= sysctl_max_map_count) 2356d4af56c5SLiam R. Howlett goto map_count_exceeded; 2357659ace58SKOSAKI Motohiro 23589760ebffSLiam R. Howlett error = __split_vma(vmi, vma, start, 0); 23591da177e4SLinus Torvalds if (error) 2360763ecb03SLiam R. Howlett goto start_split_failed; 236111f9a21aSLiam R. Howlett 23620fd5a9e2SLiam R. Howlett vma = vma_iter_load(vmi); 23631da177e4SLinus Torvalds } 23641da177e4SLinus Torvalds 2365183654ceSLiam R. Howlett prev = vma_prev(vmi); 2366763ecb03SLiam R. Howlett if (unlikely((!prev))) 2367183654ceSLiam R. Howlett vma_iter_set(vmi, start); 236811f9a21aSLiam R. Howlett 2369763ecb03SLiam R. Howlett /* 2370763ecb03SLiam R. Howlett * Detach a range of VMAs from the mm. Using next as a temp variable as 2371763ecb03SLiam R. Howlett * it is always overwritten. 2372763ecb03SLiam R. Howlett */ 2373183654ceSLiam R. Howlett for_each_vma_range(*vmi, next, end) { 2374763ecb03SLiam R. Howlett /* Does it split the end? */ 2375763ecb03SLiam R. Howlett if (next->vm_end > end) { 23766b73cff2SLiam R. Howlett error = __split_vma(vmi, next, end, 0); 23771da177e4SLinus Torvalds if (error) 2378763ecb03SLiam R. Howlett goto end_split_failed; 237911f9a21aSLiam R. Howlett } 2380763ecb03SLiam R. Howlett error = munmap_sidetree(next, &mas_detach); 2381763ecb03SLiam R. Howlett if (error) 2382763ecb03SLiam R. Howlett goto munmap_sidetree_failed; 2383763ecb03SLiam R. Howlett 2384763ecb03SLiam R. Howlett count++; 2385763ecb03SLiam R. Howlett #ifdef CONFIG_DEBUG_VM_MAPLE_TREE 2386763ecb03SLiam R. Howlett BUG_ON(next->vm_start < start); 2387763ecb03SLiam R. Howlett BUG_ON(next->vm_start > end); 2388763ecb03SLiam R. Howlett #endif 2389763ecb03SLiam R. Howlett } 2390763ecb03SLiam R. Howlett 2391183654ceSLiam R. Howlett next = vma_next(vmi); 23922376dd7cSAndrea Arcangeli if (unlikely(uf)) { 23932376dd7cSAndrea Arcangeli /* 23942376dd7cSAndrea Arcangeli * If userfaultfd_unmap_prep returns an error the vmas 2395f0953a1bSIngo Molnar * will remain split, but userland will get a 23962376dd7cSAndrea Arcangeli * highly unexpected error anyway. This is no 23972376dd7cSAndrea Arcangeli * different than the case where the first of the two 23982376dd7cSAndrea Arcangeli * __split_vma fails, but we don't undo the first 23992376dd7cSAndrea Arcangeli * split, despite we could. This is unlikely enough 24002376dd7cSAndrea Arcangeli * failure that it's not worth optimizing it for. 24012376dd7cSAndrea Arcangeli */ 240269dbe6daSLiam R. Howlett error = userfaultfd_unmap_prep(mm, start, end, uf); 240311f9a21aSLiam R. Howlett 24042376dd7cSAndrea Arcangeli if (error) 2405d4af56c5SLiam R. Howlett goto userfaultfd_error; 24062376dd7cSAndrea Arcangeli } 24072376dd7cSAndrea Arcangeli 2408763ecb03SLiam R. Howlett #if defined(CONFIG_DEBUG_VM_MAPLE_TREE) 2409763ecb03SLiam R. Howlett /* Make sure no VMAs are about to be lost. */ 2410763ecb03SLiam R. Howlett { 2411763ecb03SLiam R. Howlett MA_STATE(test, &mt_detach, start, end - 1); 2412763ecb03SLiam R. Howlett struct vm_area_struct *vma_mas, *vma_test; 2413763ecb03SLiam R. Howlett int test_count = 0; 2414763ecb03SLiam R. Howlett 2415183654ceSLiam R. Howlett vma_iter_set(vmi, start); 2416763ecb03SLiam R. Howlett rcu_read_lock(); 2417763ecb03SLiam R. Howlett vma_test = mas_find(&test, end - 1); 2418183654ceSLiam R. Howlett for_each_vma_range(*vmi, vma_mas, end) { 2419763ecb03SLiam R. Howlett BUG_ON(vma_mas != vma_test); 2420763ecb03SLiam R. Howlett test_count++; 2421763ecb03SLiam R. Howlett vma_test = mas_next(&test, end - 1); 2422763ecb03SLiam R. Howlett } 2423763ecb03SLiam R. Howlett rcu_read_unlock(); 2424763ecb03SLiam R. Howlett BUG_ON(count != test_count); 2425763ecb03SLiam R. Howlett } 2426763ecb03SLiam R. Howlett #endif 24270378c0a0SLiam R. Howlett /* Point of no return */ 2428183654ceSLiam R. Howlett vma_iter_set(vmi, start); 2429183654ceSLiam R. Howlett if (vma_iter_clear_gfp(vmi, start, end, GFP_KERNEL)) 24300378c0a0SLiam R. Howlett return -ENOMEM; 24310378c0a0SLiam R. Howlett 2432763ecb03SLiam R. Howlett mm->map_count -= count; 243311f9a21aSLiam R. Howlett /* 243411f9a21aSLiam R. Howlett * Do not downgrade mmap_lock if we are next to VM_GROWSDOWN or 243511f9a21aSLiam R. Howlett * VM_GROWSUP VMA. Such VMAs can change their size under 243611f9a21aSLiam R. Howlett * down_read(mmap_lock) and collide with the VMA we are about to unmap. 243711f9a21aSLiam R. Howlett */ 243811f9a21aSLiam R. Howlett if (downgrade) { 2439763ecb03SLiam R. Howlett if (next && (next->vm_flags & VM_GROWSDOWN)) 244011f9a21aSLiam R. Howlett downgrade = false; 244111f9a21aSLiam R. Howlett else if (prev && (prev->vm_flags & VM_GROWSUP)) 244211f9a21aSLiam R. Howlett downgrade = false; 244311f9a21aSLiam R. Howlett else 2444d8ed45c5SMichel Lespinasse mmap_write_downgrade(mm); 244511f9a21aSLiam R. Howlett } 2446dd2283f2SYang Shi 2447763ecb03SLiam R. Howlett unmap_region(mm, &mt_detach, vma, prev, next, start, end); 2448763ecb03SLiam R. Howlett /* Statistics and freeing VMAs */ 2449763ecb03SLiam R. Howlett mas_set(&mas_detach, start); 2450763ecb03SLiam R. Howlett remove_mt(mm, &mas_detach); 2451763ecb03SLiam R. Howlett __mt_destroy(&mt_detach); 24521da177e4SLinus Torvalds 2453524e00b3SLiam R. Howlett 2454524e00b3SLiam R. Howlett validate_mm(mm); 2455dd2283f2SYang Shi return downgrade ? 1 : 0; 2456d4af56c5SLiam R. Howlett 2457d4af56c5SLiam R. Howlett userfaultfd_error: 2458763ecb03SLiam R. Howlett munmap_sidetree_failed: 2459763ecb03SLiam R. Howlett end_split_failed: 2460763ecb03SLiam R. Howlett __mt_destroy(&mt_detach); 2461763ecb03SLiam R. Howlett start_split_failed: 2462763ecb03SLiam R. Howlett map_count_exceeded: 2463d4af56c5SLiam R. Howlett return error; 24641da177e4SLinus Torvalds } 24651da177e4SLinus Torvalds 246611f9a21aSLiam R. Howlett /* 2467183654ceSLiam R. Howlett * do_vmi_munmap() - munmap a given range. 2468183654ceSLiam R. Howlett * @vmi: The vma iterator 246911f9a21aSLiam R. Howlett * @mm: The mm_struct 247011f9a21aSLiam R. Howlett * @start: The start address to munmap 247111f9a21aSLiam R. Howlett * @len: The length of the range to munmap 247211f9a21aSLiam R. Howlett * @uf: The userfaultfd list_head 247311f9a21aSLiam R. Howlett * @downgrade: set to true if the user wants to attempt to write_downgrade the 24748651a137SLorenzo Stoakes * mmap_lock 247511f9a21aSLiam R. Howlett * 247611f9a21aSLiam R. Howlett * This function takes a @mas that is either pointing to the previous VMA or set 247711f9a21aSLiam R. Howlett * to MA_START and sets it up to remove the mapping(s). The @len will be 247811f9a21aSLiam R. Howlett * aligned and any arch_unmap work will be preformed. 247911f9a21aSLiam R. Howlett * 248011f9a21aSLiam R. Howlett * Returns: -EINVAL on failure, 1 on success and unlock, 0 otherwise. 248111f9a21aSLiam R. Howlett */ 2482183654ceSLiam R. Howlett int do_vmi_munmap(struct vma_iterator *vmi, struct mm_struct *mm, 248311f9a21aSLiam R. Howlett unsigned long start, size_t len, struct list_head *uf, 248411f9a21aSLiam R. Howlett bool downgrade) 248511f9a21aSLiam R. Howlett { 248611f9a21aSLiam R. Howlett unsigned long end; 248711f9a21aSLiam R. Howlett struct vm_area_struct *vma; 248811f9a21aSLiam R. Howlett 248911f9a21aSLiam R. Howlett if ((offset_in_page(start)) || start > TASK_SIZE || len > TASK_SIZE-start) 249011f9a21aSLiam R. Howlett return -EINVAL; 249111f9a21aSLiam R. Howlett 249211f9a21aSLiam R. Howlett end = start + PAGE_ALIGN(len); 249311f9a21aSLiam R. Howlett if (end == start) 249411f9a21aSLiam R. Howlett return -EINVAL; 249511f9a21aSLiam R. Howlett 249611f9a21aSLiam R. Howlett /* arch_unmap() might do unmaps itself. */ 249711f9a21aSLiam R. Howlett arch_unmap(mm, start, end); 249811f9a21aSLiam R. Howlett 249911f9a21aSLiam R. Howlett /* Find the first overlapping VMA */ 2500183654ceSLiam R. Howlett vma = vma_find(vmi, end); 250111f9a21aSLiam R. Howlett if (!vma) 250211f9a21aSLiam R. Howlett return 0; 250311f9a21aSLiam R. Howlett 2504183654ceSLiam R. Howlett return do_vmi_align_munmap(vmi, vma, mm, start, end, uf, downgrade); 250511f9a21aSLiam R. Howlett } 250611f9a21aSLiam R. Howlett 250711f9a21aSLiam R. Howlett /* do_munmap() - Wrapper function for non-maple tree aware do_munmap() calls. 250811f9a21aSLiam R. Howlett * @mm: The mm_struct 250911f9a21aSLiam R. Howlett * @start: The start address to munmap 251011f9a21aSLiam R. Howlett * @len: The length to be munmapped. 251111f9a21aSLiam R. Howlett * @uf: The userfaultfd list_head 251211f9a21aSLiam R. Howlett */ 2513dd2283f2SYang Shi int do_munmap(struct mm_struct *mm, unsigned long start, size_t len, 2514dd2283f2SYang Shi struct list_head *uf) 2515dd2283f2SYang Shi { 2516183654ceSLiam R. Howlett VMA_ITERATOR(vmi, mm, start); 251711f9a21aSLiam R. Howlett 2518183654ceSLiam R. Howlett return do_vmi_munmap(&vmi, mm, start, len, uf, false); 2519dd2283f2SYang Shi } 2520dd2283f2SYang Shi 2521e99668a5SLiam R. Howlett unsigned long mmap_region(struct file *file, unsigned long addr, 2522e99668a5SLiam R. Howlett unsigned long len, vm_flags_t vm_flags, unsigned long pgoff, 2523e99668a5SLiam R. Howlett struct list_head *uf) 2524e99668a5SLiam R. Howlett { 2525e99668a5SLiam R. Howlett struct mm_struct *mm = current->mm; 2526e99668a5SLiam R. Howlett struct vm_area_struct *vma = NULL; 2527e99668a5SLiam R. Howlett struct vm_area_struct *next, *prev, *merge; 2528e99668a5SLiam R. Howlett pgoff_t pglen = len >> PAGE_SHIFT; 2529e99668a5SLiam R. Howlett unsigned long charged = 0; 2530e99668a5SLiam R. Howlett unsigned long end = addr + len; 2531e99668a5SLiam R. Howlett unsigned long merge_start = addr, merge_end = end; 2532e99668a5SLiam R. Howlett pgoff_t vm_pgoff; 2533e99668a5SLiam R. Howlett int error; 2534183654ceSLiam R. Howlett VMA_ITERATOR(vmi, mm, addr); 2535e99668a5SLiam R. Howlett 2536e99668a5SLiam R. Howlett /* Check against address space limit. */ 2537e99668a5SLiam R. Howlett if (!may_expand_vm(mm, vm_flags, len >> PAGE_SHIFT)) { 2538e99668a5SLiam R. Howlett unsigned long nr_pages; 2539e99668a5SLiam R. Howlett 2540e99668a5SLiam R. Howlett /* 2541e99668a5SLiam R. Howlett * MAP_FIXED may remove pages of mappings that intersects with 2542e99668a5SLiam R. Howlett * requested mapping. Account for the pages it would unmap. 2543e99668a5SLiam R. Howlett */ 2544e99668a5SLiam R. Howlett nr_pages = count_vma_pages_range(mm, addr, end); 2545e99668a5SLiam R. Howlett 2546e99668a5SLiam R. Howlett if (!may_expand_vm(mm, vm_flags, 2547e99668a5SLiam R. Howlett (len >> PAGE_SHIFT) - nr_pages)) 2548e99668a5SLiam R. Howlett return -ENOMEM; 2549e99668a5SLiam R. Howlett } 2550e99668a5SLiam R. Howlett 2551e99668a5SLiam R. Howlett /* Unmap any existing mapping in the area */ 2552183654ceSLiam R. Howlett if (do_vmi_munmap(&vmi, mm, addr, len, uf, false)) 2553e99668a5SLiam R. Howlett return -ENOMEM; 2554e99668a5SLiam R. Howlett 2555e99668a5SLiam R. Howlett /* 2556e99668a5SLiam R. Howlett * Private writable mapping: check memory availability 2557e99668a5SLiam R. Howlett */ 2558e99668a5SLiam R. Howlett if (accountable_mapping(file, vm_flags)) { 2559e99668a5SLiam R. Howlett charged = len >> PAGE_SHIFT; 2560e99668a5SLiam R. Howlett if (security_vm_enough_memory_mm(mm, charged)) 2561e99668a5SLiam R. Howlett return -ENOMEM; 2562e99668a5SLiam R. Howlett vm_flags |= VM_ACCOUNT; 2563e99668a5SLiam R. Howlett } 2564e99668a5SLiam R. Howlett 2565183654ceSLiam R. Howlett next = vma_next(&vmi); 2566183654ceSLiam R. Howlett prev = vma_prev(&vmi); 2567e99668a5SLiam R. Howlett if (vm_flags & VM_SPECIAL) 2568e99668a5SLiam R. Howlett goto cannot_expand; 2569e99668a5SLiam R. Howlett 2570e99668a5SLiam R. Howlett /* Attempt to expand an old mapping */ 2571e99668a5SLiam R. Howlett /* Check next */ 2572e99668a5SLiam R. Howlett if (next && next->vm_start == end && !vma_policy(next) && 2573e99668a5SLiam R. Howlett can_vma_merge_before(next, vm_flags, NULL, file, pgoff+pglen, 2574e99668a5SLiam R. Howlett NULL_VM_UFFD_CTX, NULL)) { 2575e99668a5SLiam R. Howlett merge_end = next->vm_end; 2576e99668a5SLiam R. Howlett vma = next; 2577e99668a5SLiam R. Howlett vm_pgoff = next->vm_pgoff - pglen; 2578e99668a5SLiam R. Howlett } 2579e99668a5SLiam R. Howlett 2580e99668a5SLiam R. Howlett /* Check prev */ 2581e99668a5SLiam R. Howlett if (prev && prev->vm_end == addr && !vma_policy(prev) && 2582e99668a5SLiam R. Howlett (vma ? can_vma_merge_after(prev, vm_flags, vma->anon_vma, file, 2583e99668a5SLiam R. Howlett pgoff, vma->vm_userfaultfd_ctx, NULL) : 2584e99668a5SLiam R. Howlett can_vma_merge_after(prev, vm_flags, NULL, file, pgoff, 2585e99668a5SLiam R. Howlett NULL_VM_UFFD_CTX, NULL))) { 2586e99668a5SLiam R. Howlett merge_start = prev->vm_start; 2587e99668a5SLiam R. Howlett vma = prev; 2588e99668a5SLiam R. Howlett vm_pgoff = prev->vm_pgoff; 2589e99668a5SLiam R. Howlett } 2590e99668a5SLiam R. Howlett 2591e99668a5SLiam R. Howlett 2592e99668a5SLiam R. Howlett /* Actually expand, if possible */ 2593e99668a5SLiam R. Howlett if (vma && 25943c441ab7SLiam R. Howlett !vma_expand(&vmi, vma, merge_start, merge_end, vm_pgoff, next)) { 2595e99668a5SLiam R. Howlett khugepaged_enter_vma(vma, vm_flags); 2596e99668a5SLiam R. Howlett goto expanded; 2597e99668a5SLiam R. Howlett } 2598e99668a5SLiam R. Howlett 2599e99668a5SLiam R. Howlett cannot_expand: 2600e99668a5SLiam R. Howlett /* 2601e99668a5SLiam R. Howlett * Determine the object being mapped and call the appropriate 2602e99668a5SLiam R. Howlett * specific mapper. the address has already been validated, but 2603e99668a5SLiam R. Howlett * not unmapped, but the maps are removed from the list. 2604e99668a5SLiam R. Howlett */ 2605e99668a5SLiam R. Howlett vma = vm_area_alloc(mm); 2606e99668a5SLiam R. Howlett if (!vma) { 2607e99668a5SLiam R. Howlett error = -ENOMEM; 2608e99668a5SLiam R. Howlett goto unacct_error; 2609e99668a5SLiam R. Howlett } 2610e99668a5SLiam R. Howlett 26110fd5a9e2SLiam R. Howlett vma_iter_set(&vmi, addr); 2612e99668a5SLiam R. Howlett vma->vm_start = addr; 2613e99668a5SLiam R. Howlett vma->vm_end = end; 2614e99668a5SLiam R. Howlett vma->vm_flags = vm_flags; 2615e99668a5SLiam R. Howlett vma->vm_page_prot = vm_get_page_prot(vm_flags); 2616e99668a5SLiam R. Howlett vma->vm_pgoff = pgoff; 2617e99668a5SLiam R. Howlett 2618e99668a5SLiam R. Howlett if (file) { 2619e99668a5SLiam R. Howlett if (vm_flags & VM_SHARED) { 2620e99668a5SLiam R. Howlett error = mapping_map_writable(file->f_mapping); 2621e99668a5SLiam R. Howlett if (error) 2622e99668a5SLiam R. Howlett goto free_vma; 2623e99668a5SLiam R. Howlett } 2624e99668a5SLiam R. Howlett 2625e99668a5SLiam R. Howlett vma->vm_file = get_file(file); 2626e99668a5SLiam R. Howlett error = call_mmap(file, vma); 2627e99668a5SLiam R. Howlett if (error) 2628e99668a5SLiam R. Howlett goto unmap_and_free_vma; 2629e99668a5SLiam R. Howlett 2630a57b7051SLiam Howlett /* 2631a57b7051SLiam Howlett * Expansion is handled above, merging is handled below. 2632a57b7051SLiam Howlett * Drivers should not alter the address of the VMA. 2633e99668a5SLiam R. Howlett */ 2634a57b7051SLiam Howlett error = -EINVAL; 2635cc8d1b09SLiam R. Howlett if (WARN_ON((addr != vma->vm_start))) 2636a57b7051SLiam Howlett goto close_and_free_vma; 2637e99668a5SLiam R. Howlett 2638cc8d1b09SLiam R. Howlett vma_iter_set(&vmi, addr); 2639e99668a5SLiam R. Howlett /* 2640e99668a5SLiam R. Howlett * If vm_flags changed after call_mmap(), we should try merge 2641e99668a5SLiam R. Howlett * vma again as we may succeed this time. 2642e99668a5SLiam R. Howlett */ 2643e99668a5SLiam R. Howlett if (unlikely(vm_flags != vma->vm_flags && prev)) { 26449760ebffSLiam R. Howlett merge = vma_merge(&vmi, mm, prev, vma->vm_start, 26459760ebffSLiam R. Howlett vma->vm_end, vma->vm_flags, NULL, 26469760ebffSLiam R. Howlett vma->vm_file, vma->vm_pgoff, NULL, 26479760ebffSLiam R. Howlett NULL_VM_UFFD_CTX, NULL); 2648e99668a5SLiam R. Howlett if (merge) { 2649e99668a5SLiam R. Howlett /* 2650e99668a5SLiam R. Howlett * ->mmap() can change vma->vm_file and fput 2651e99668a5SLiam R. Howlett * the original file. So fput the vma->vm_file 2652e99668a5SLiam R. Howlett * here or we would add an extra fput for file 2653e99668a5SLiam R. Howlett * and cause general protection fault 2654e99668a5SLiam R. Howlett * ultimately. 2655e99668a5SLiam R. Howlett */ 2656e99668a5SLiam R. Howlett fput(vma->vm_file); 2657e99668a5SLiam R. Howlett vm_area_free(vma); 2658e99668a5SLiam R. Howlett vma = merge; 2659e99668a5SLiam R. Howlett /* Update vm_flags to pick up the change. */ 2660e99668a5SLiam R. Howlett vm_flags = vma->vm_flags; 2661e99668a5SLiam R. Howlett goto unmap_writable; 2662e99668a5SLiam R. Howlett } 2663e99668a5SLiam R. Howlett } 2664e99668a5SLiam R. Howlett 2665e99668a5SLiam R. Howlett vm_flags = vma->vm_flags; 2666e99668a5SLiam R. Howlett } else if (vm_flags & VM_SHARED) { 2667e99668a5SLiam R. Howlett error = shmem_zero_setup(vma); 2668e99668a5SLiam R. Howlett if (error) 2669e99668a5SLiam R. Howlett goto free_vma; 2670e99668a5SLiam R. Howlett } else { 2671e99668a5SLiam R. Howlett vma_set_anonymous(vma); 2672e99668a5SLiam R. Howlett } 2673e99668a5SLiam R. Howlett 2674b507808eSJoey Gouly if (map_deny_write_exec(vma, vma->vm_flags)) { 2675b507808eSJoey Gouly error = -EACCES; 2676b507808eSJoey Gouly if (file) 2677b507808eSJoey Gouly goto close_and_free_vma; 2678b507808eSJoey Gouly else if (vma->vm_file) 2679b507808eSJoey Gouly goto unmap_and_free_vma; 2680b507808eSJoey Gouly else 2681b507808eSJoey Gouly goto free_vma; 2682b507808eSJoey Gouly } 2683b507808eSJoey Gouly 2684e99668a5SLiam R. Howlett /* Allow architectures to sanity-check the vm_flags */ 2685e99668a5SLiam R. Howlett error = -EINVAL; 2686cc8d1b09SLiam R. Howlett if (!arch_validate_flags(vma->vm_flags)) 2687deb0f656SCarlos Llamas goto close_and_free_vma; 2688e99668a5SLiam R. Howlett 2689e99668a5SLiam R. Howlett error = -ENOMEM; 2690cc8d1b09SLiam R. Howlett if (vma_iter_prealloc(&vmi)) 26915789151eSMike Kravetz goto close_and_free_vma; 2692e99668a5SLiam R. Howlett 2693e99668a5SLiam R. Howlett if (vma->vm_file) 2694e99668a5SLiam R. Howlett i_mmap_lock_write(vma->vm_file->f_mapping); 2695e99668a5SLiam R. Howlett 2696183654ceSLiam R. Howlett vma_iter_store(&vmi, vma); 2697e99668a5SLiam R. Howlett mm->map_count++; 2698e99668a5SLiam R. Howlett if (vma->vm_file) { 2699e99668a5SLiam R. Howlett if (vma->vm_flags & VM_SHARED) 2700e99668a5SLiam R. Howlett mapping_allow_writable(vma->vm_file->f_mapping); 2701e99668a5SLiam R. Howlett 2702e99668a5SLiam R. Howlett flush_dcache_mmap_lock(vma->vm_file->f_mapping); 2703e99668a5SLiam R. Howlett vma_interval_tree_insert(vma, &vma->vm_file->f_mapping->i_mmap); 2704e99668a5SLiam R. Howlett flush_dcache_mmap_unlock(vma->vm_file->f_mapping); 2705e99668a5SLiam R. Howlett i_mmap_unlock_write(vma->vm_file->f_mapping); 2706e99668a5SLiam R. Howlett } 2707e99668a5SLiam R. Howlett 2708e99668a5SLiam R. Howlett /* 2709e99668a5SLiam R. Howlett * vma_merge() calls khugepaged_enter_vma() either, the below 2710e99668a5SLiam R. Howlett * call covers the non-merge case. 2711e99668a5SLiam R. Howlett */ 2712e99668a5SLiam R. Howlett khugepaged_enter_vma(vma, vma->vm_flags); 2713e99668a5SLiam R. Howlett 2714e99668a5SLiam R. Howlett /* Once vma denies write, undo our temporary denial count */ 2715e99668a5SLiam R. Howlett unmap_writable: 2716e99668a5SLiam R. Howlett if (file && vm_flags & VM_SHARED) 2717e99668a5SLiam R. Howlett mapping_unmap_writable(file->f_mapping); 2718e99668a5SLiam R. Howlett file = vma->vm_file; 2719e99668a5SLiam R. Howlett expanded: 2720e99668a5SLiam R. Howlett perf_event_mmap(vma); 2721e99668a5SLiam R. Howlett 2722e99668a5SLiam R. Howlett vm_stat_account(mm, vm_flags, len >> PAGE_SHIFT); 2723e99668a5SLiam R. Howlett if (vm_flags & VM_LOCKED) { 2724e99668a5SLiam R. Howlett if ((vm_flags & VM_SPECIAL) || vma_is_dax(vma) || 2725e99668a5SLiam R. Howlett is_vm_hugetlb_page(vma) || 2726e99668a5SLiam R. Howlett vma == get_gate_vma(current->mm)) 2727e99668a5SLiam R. Howlett vma->vm_flags &= VM_LOCKED_CLEAR_MASK; 2728e99668a5SLiam R. Howlett else 2729e99668a5SLiam R. Howlett mm->locked_vm += (len >> PAGE_SHIFT); 2730e99668a5SLiam R. Howlett } 2731e99668a5SLiam R. Howlett 2732e99668a5SLiam R. Howlett if (file) 2733e99668a5SLiam R. Howlett uprobe_mmap(vma); 2734e99668a5SLiam R. Howlett 2735e99668a5SLiam R. Howlett /* 2736e99668a5SLiam R. Howlett * New (or expanded) vma always get soft dirty status. 2737e99668a5SLiam R. Howlett * Otherwise user-space soft-dirty page tracker won't 2738e99668a5SLiam R. Howlett * be able to distinguish situation when vma area unmapped, 2739e99668a5SLiam R. Howlett * then new mapped in-place (which must be aimed as 2740e99668a5SLiam R. Howlett * a completely new data area). 2741e99668a5SLiam R. Howlett */ 2742e99668a5SLiam R. Howlett vma->vm_flags |= VM_SOFTDIRTY; 2743e99668a5SLiam R. Howlett 2744e99668a5SLiam R. Howlett vma_set_page_prot(vma); 2745e99668a5SLiam R. Howlett 2746e99668a5SLiam R. Howlett validate_mm(mm); 2747e99668a5SLiam R. Howlett return addr; 2748e99668a5SLiam R. Howlett 2749deb0f656SCarlos Llamas close_and_free_vma: 2750cc8d1b09SLiam R. Howlett if (file && vma->vm_ops && vma->vm_ops->close) 2751deb0f656SCarlos Llamas vma->vm_ops->close(vma); 2752cc8d1b09SLiam R. Howlett 2753cc8d1b09SLiam R. Howlett if (file || vma->vm_file) { 2754e99668a5SLiam R. Howlett unmap_and_free_vma: 2755e99668a5SLiam R. Howlett fput(vma->vm_file); 2756e99668a5SLiam R. Howlett vma->vm_file = NULL; 2757e99668a5SLiam R. Howlett 2758e99668a5SLiam R. Howlett /* Undo any partial mapping done by a device driver. */ 2759cc8d1b09SLiam R. Howlett unmap_region(mm, &mm->mm_mt, vma, prev, next, vma->vm_start, 2760cc8d1b09SLiam R. Howlett vma->vm_end); 2761cc8d1b09SLiam R. Howlett } 2762cc674ab3SLi Zetao if (file && (vm_flags & VM_SHARED)) 2763e99668a5SLiam R. Howlett mapping_unmap_writable(file->f_mapping); 2764e99668a5SLiam R. Howlett free_vma: 2765e99668a5SLiam R. Howlett vm_area_free(vma); 2766e99668a5SLiam R. Howlett unacct_error: 2767e99668a5SLiam R. Howlett if (charged) 2768e99668a5SLiam R. Howlett vm_unacct_memory(charged); 2769e99668a5SLiam R. Howlett validate_mm(mm); 2770e99668a5SLiam R. Howlett return error; 2771e99668a5SLiam R. Howlett } 2772e99668a5SLiam R. Howlett 2773dd2283f2SYang Shi static int __vm_munmap(unsigned long start, size_t len, bool downgrade) 2774a46ef99dSLinus Torvalds { 2775a46ef99dSLinus Torvalds int ret; 2776bfce281cSAl Viro struct mm_struct *mm = current->mm; 2777897ab3e0SMike Rapoport LIST_HEAD(uf); 2778183654ceSLiam R. Howlett VMA_ITERATOR(vmi, mm, start); 2779a46ef99dSLinus Torvalds 2780d8ed45c5SMichel Lespinasse if (mmap_write_lock_killable(mm)) 2781ae798783SMichal Hocko return -EINTR; 2782ae798783SMichal Hocko 2783183654ceSLiam R. Howlett ret = do_vmi_munmap(&vmi, mm, start, len, &uf, downgrade); 2784dd2283f2SYang Shi /* 2785c1e8d7c6SMichel Lespinasse * Returning 1 indicates mmap_lock is downgraded. 2786dd2283f2SYang Shi * But 1 is not legal return value of vm_munmap() and munmap(), reset 2787dd2283f2SYang Shi * it to 0 before return. 2788dd2283f2SYang Shi */ 2789dd2283f2SYang Shi if (ret == 1) { 2790d8ed45c5SMichel Lespinasse mmap_read_unlock(mm); 2791dd2283f2SYang Shi ret = 0; 2792dd2283f2SYang Shi } else 2793d8ed45c5SMichel Lespinasse mmap_write_unlock(mm); 2794dd2283f2SYang Shi 2795897ab3e0SMike Rapoport userfaultfd_unmap_complete(mm, &uf); 2796a46ef99dSLinus Torvalds return ret; 2797a46ef99dSLinus Torvalds } 2798dd2283f2SYang Shi 2799dd2283f2SYang Shi int vm_munmap(unsigned long start, size_t len) 2800dd2283f2SYang Shi { 2801dd2283f2SYang Shi return __vm_munmap(start, len, false); 2802dd2283f2SYang Shi } 2803a46ef99dSLinus Torvalds EXPORT_SYMBOL(vm_munmap); 2804a46ef99dSLinus Torvalds 28056a6160a7SHeiko Carstens SYSCALL_DEFINE2(munmap, unsigned long, addr, size_t, len) 28061da177e4SLinus Torvalds { 2807ce18d171SCatalin Marinas addr = untagged_addr(addr); 2808dd2283f2SYang Shi return __vm_munmap(addr, len, true); 28091da177e4SLinus Torvalds } 28101da177e4SLinus Torvalds 2811c8d78c18SKirill A. Shutemov 2812c8d78c18SKirill A. Shutemov /* 2813c8d78c18SKirill A. Shutemov * Emulation of deprecated remap_file_pages() syscall. 2814c8d78c18SKirill A. Shutemov */ 2815c8d78c18SKirill A. Shutemov SYSCALL_DEFINE5(remap_file_pages, unsigned long, start, unsigned long, size, 2816c8d78c18SKirill A. Shutemov unsigned long, prot, unsigned long, pgoff, unsigned long, flags) 2817c8d78c18SKirill A. Shutemov { 2818c8d78c18SKirill A. Shutemov 2819c8d78c18SKirill A. Shutemov struct mm_struct *mm = current->mm; 2820c8d78c18SKirill A. Shutemov struct vm_area_struct *vma; 2821c8d78c18SKirill A. Shutemov unsigned long populate = 0; 2822c8d78c18SKirill A. Shutemov unsigned long ret = -EINVAL; 2823c8d78c18SKirill A. Shutemov struct file *file; 2824c8d78c18SKirill A. Shutemov 2825ee65728eSMike Rapoport pr_warn_once("%s (%d) uses deprecated remap_file_pages() syscall. See Documentation/mm/remap_file_pages.rst.\n", 2826c8d78c18SKirill A. Shutemov current->comm, current->pid); 2827c8d78c18SKirill A. Shutemov 2828c8d78c18SKirill A. Shutemov if (prot) 2829c8d78c18SKirill A. Shutemov return ret; 2830c8d78c18SKirill A. Shutemov start = start & PAGE_MASK; 2831c8d78c18SKirill A. Shutemov size = size & PAGE_MASK; 2832c8d78c18SKirill A. Shutemov 2833c8d78c18SKirill A. Shutemov if (start + size <= start) 2834c8d78c18SKirill A. Shutemov return ret; 2835c8d78c18SKirill A. Shutemov 2836c8d78c18SKirill A. Shutemov /* Does pgoff wrap? */ 2837c8d78c18SKirill A. Shutemov if (pgoff + (size >> PAGE_SHIFT) < pgoff) 2838c8d78c18SKirill A. Shutemov return ret; 2839c8d78c18SKirill A. Shutemov 2840d8ed45c5SMichel Lespinasse if (mmap_write_lock_killable(mm)) 2841dc0ef0dfSMichal Hocko return -EINTR; 2842dc0ef0dfSMichal Hocko 28439b593cb2SLiam R. Howlett vma = vma_lookup(mm, start); 2844c8d78c18SKirill A. Shutemov 2845c8d78c18SKirill A. Shutemov if (!vma || !(vma->vm_flags & VM_SHARED)) 2846c8d78c18SKirill A. Shutemov goto out; 2847c8d78c18SKirill A. Shutemov 284848f7df32SKirill A. Shutemov if (start + size > vma->vm_end) { 2849763ecb03SLiam R. Howlett VMA_ITERATOR(vmi, mm, vma->vm_end); 2850763ecb03SLiam R. Howlett struct vm_area_struct *next, *prev = vma; 285148f7df32SKirill A. Shutemov 2852763ecb03SLiam R. Howlett for_each_vma_range(vmi, next, start + size) { 285348f7df32SKirill A. Shutemov /* hole between vmas ? */ 2854763ecb03SLiam R. Howlett if (next->vm_start != prev->vm_end) 285548f7df32SKirill A. Shutemov goto out; 285648f7df32SKirill A. Shutemov 285748f7df32SKirill A. Shutemov if (next->vm_file != vma->vm_file) 285848f7df32SKirill A. Shutemov goto out; 285948f7df32SKirill A. Shutemov 286048f7df32SKirill A. Shutemov if (next->vm_flags != vma->vm_flags) 286148f7df32SKirill A. Shutemov goto out; 286248f7df32SKirill A. Shutemov 28631db43d3fSLiam Howlett if (start + size <= next->vm_end) 28641db43d3fSLiam Howlett break; 28651db43d3fSLiam Howlett 2866763ecb03SLiam R. Howlett prev = next; 286748f7df32SKirill A. Shutemov } 286848f7df32SKirill A. Shutemov 286948f7df32SKirill A. Shutemov if (!next) 2870c8d78c18SKirill A. Shutemov goto out; 2871c8d78c18SKirill A. Shutemov } 2872c8d78c18SKirill A. Shutemov 2873c8d78c18SKirill A. Shutemov prot |= vma->vm_flags & VM_READ ? PROT_READ : 0; 2874c8d78c18SKirill A. Shutemov prot |= vma->vm_flags & VM_WRITE ? PROT_WRITE : 0; 2875c8d78c18SKirill A. Shutemov prot |= vma->vm_flags & VM_EXEC ? PROT_EXEC : 0; 2876c8d78c18SKirill A. Shutemov 2877c8d78c18SKirill A. Shutemov flags &= MAP_NONBLOCK; 2878c8d78c18SKirill A. Shutemov flags |= MAP_SHARED | MAP_FIXED | MAP_POPULATE; 2879fce000b1SLiam Howlett if (vma->vm_flags & VM_LOCKED) 2880c8d78c18SKirill A. Shutemov flags |= MAP_LOCKED; 288148f7df32SKirill A. Shutemov 2882c8d78c18SKirill A. Shutemov file = get_file(vma->vm_file); 288345e55300SPeter Collingbourne ret = do_mmap(vma->vm_file, start, size, 2884897ab3e0SMike Rapoport prot, flags, pgoff, &populate, NULL); 2885c8d78c18SKirill A. Shutemov fput(file); 2886c8d78c18SKirill A. Shutemov out: 2887d8ed45c5SMichel Lespinasse mmap_write_unlock(mm); 2888c8d78c18SKirill A. Shutemov if (populate) 2889c8d78c18SKirill A. Shutemov mm_populate(ret, populate); 2890c8d78c18SKirill A. Shutemov if (!IS_ERR_VALUE(ret)) 2891c8d78c18SKirill A. Shutemov ret = 0; 2892c8d78c18SKirill A. Shutemov return ret; 2893c8d78c18SKirill A. Shutemov } 2894c8d78c18SKirill A. Shutemov 28951da177e4SLinus Torvalds /* 289627b26701SLiam R. Howlett * do_vma_munmap() - Unmap a full or partial vma. 289727b26701SLiam R. Howlett * @vmi: The vma iterator pointing at the vma 289827b26701SLiam R. Howlett * @vma: The first vma to be munmapped 289927b26701SLiam R. Howlett * @start: the start of the address to unmap 290027b26701SLiam R. Howlett * @end: The end of the address to unmap 29012e7ce7d3SLiam R. Howlett * @uf: The userfaultfd list_head 290227b26701SLiam R. Howlett * @downgrade: Attempt to downgrade or not 29032e7ce7d3SLiam R. Howlett * 290427b26701SLiam R. Howlett * Returns: 0 on success and not downgraded, 1 on success and downgraded. 290527b26701SLiam R. Howlett * unmaps a VMA mapping when the vma iterator is already in position. 290627b26701SLiam R. Howlett * Does not handle alignment. 29071da177e4SLinus Torvalds */ 290827b26701SLiam R. Howlett int do_vma_munmap(struct vma_iterator *vmi, struct vm_area_struct *vma, 290927b26701SLiam R. Howlett unsigned long start, unsigned long end, 291027b26701SLiam R. Howlett struct list_head *uf, bool downgrade) 29112e7ce7d3SLiam R. Howlett { 29122e7ce7d3SLiam R. Howlett struct mm_struct *mm = vma->vm_mm; 29132e7ce7d3SLiam R. Howlett int ret; 29142e7ce7d3SLiam R. Howlett 291527b26701SLiam R. Howlett arch_unmap(mm, start, end); 291627b26701SLiam R. Howlett ret = do_vmi_align_munmap(vmi, vma, mm, start, end, uf, downgrade); 29172e7ce7d3SLiam R. Howlett validate_mm_mt(mm); 29182e7ce7d3SLiam R. Howlett return ret; 29192e7ce7d3SLiam R. Howlett } 29202e7ce7d3SLiam R. Howlett 29212e7ce7d3SLiam R. Howlett /* 29222e7ce7d3SLiam R. Howlett * do_brk_flags() - Increase the brk vma if the flags match. 292392fed820SLiam R. Howlett * @vmi: The vma iterator 29242e7ce7d3SLiam R. Howlett * @addr: The start address 29252e7ce7d3SLiam R. Howlett * @len: The length of the increase 29262e7ce7d3SLiam R. Howlett * @vma: The vma, 29272e7ce7d3SLiam R. Howlett * @flags: The VMA Flags 29282e7ce7d3SLiam R. Howlett * 29292e7ce7d3SLiam R. Howlett * Extend the brk VMA from addr to addr + len. If the VMA is NULL or the flags 29302e7ce7d3SLiam R. Howlett * do not match then create a new anonymous VMA. Eventually we may be able to 29312e7ce7d3SLiam R. Howlett * do some brk-specific accounting here. 29322e7ce7d3SLiam R. Howlett */ 293392fed820SLiam R. Howlett static int do_brk_flags(struct vma_iterator *vmi, struct vm_area_struct *vma, 2934763ecb03SLiam R. Howlett unsigned long addr, unsigned long len, unsigned long flags) 29351da177e4SLinus Torvalds { 29361da177e4SLinus Torvalds struct mm_struct *mm = current->mm; 29372e7ce7d3SLiam R. Howlett 2938d4af56c5SLiam R. Howlett validate_mm_mt(mm); 29392e7ce7d3SLiam R. Howlett /* 29402e7ce7d3SLiam R. Howlett * Check against address space limits by the changed size 29412e7ce7d3SLiam R. Howlett * Note: This happens *after* clearing old mappings in some code paths. 29422e7ce7d3SLiam R. Howlett */ 294316e72e9bSDenys Vlasenko flags |= VM_DATA_DEFAULT_FLAGS | VM_ACCOUNT | mm->def_flags; 294484638335SKonstantin Khlebnikov if (!may_expand_vm(mm, flags, len >> PAGE_SHIFT)) 29451da177e4SLinus Torvalds return -ENOMEM; 29461da177e4SLinus Torvalds 29471da177e4SLinus Torvalds if (mm->map_count > sysctl_max_map_count) 29481da177e4SLinus Torvalds return -ENOMEM; 29491da177e4SLinus Torvalds 2950191c5424SAl Viro if (security_vm_enough_memory_mm(mm, len >> PAGE_SHIFT)) 29511da177e4SLinus Torvalds return -ENOMEM; 29521da177e4SLinus Torvalds 29531da177e4SLinus Torvalds /* 29542e7ce7d3SLiam R. Howlett * Expand the existing vma if possible; Note that singular lists do not 29552e7ce7d3SLiam R. Howlett * occur after forking, so the expand will only happen on new VMAs. 29561da177e4SLinus Torvalds */ 29576c28ca64SLiam Howlett if (vma && vma->vm_end == addr && !vma_policy(vma) && 29586c28ca64SLiam Howlett can_vma_merge_after(vma, flags, NULL, NULL, 29596c28ca64SLiam Howlett addr >> PAGE_SHIFT, NULL_VM_UFFD_CTX, NULL)) { 296092fed820SLiam R. Howlett if (vma_iter_prealloc(vmi)) 2961675eaca1SAlistair Popple goto unacct_fail; 296228c5609fSLiam Howlett 296328c5609fSLiam Howlett vma_adjust_trans_huge(vma, vma->vm_start, addr + len, 0); 29642e7ce7d3SLiam R. Howlett if (vma->anon_vma) { 29652e7ce7d3SLiam R. Howlett anon_vma_lock_write(vma->anon_vma); 29662e7ce7d3SLiam R. Howlett anon_vma_interval_tree_pre_update_vma(vma); 29671da177e4SLinus Torvalds } 29682e7ce7d3SLiam R. Howlett vma->vm_end = addr + len; 29692e7ce7d3SLiam R. Howlett vma->vm_flags |= VM_SOFTDIRTY; 297092fed820SLiam R. Howlett vma_iter_store(vmi, vma); 29712e7ce7d3SLiam R. Howlett 29722e7ce7d3SLiam R. Howlett if (vma->anon_vma) { 29732e7ce7d3SLiam R. Howlett anon_vma_interval_tree_post_update_vma(vma); 29742e7ce7d3SLiam R. Howlett anon_vma_unlock_write(vma->anon_vma); 29752e7ce7d3SLiam R. Howlett } 29762e7ce7d3SLiam R. Howlett khugepaged_enter_vma(vma, flags); 29772e7ce7d3SLiam R. Howlett goto out; 29782e7ce7d3SLiam R. Howlett } 29792e7ce7d3SLiam R. Howlett 29802e7ce7d3SLiam R. Howlett /* create a vma struct for an anonymous mapping */ 29812e7ce7d3SLiam R. Howlett vma = vm_area_alloc(mm); 29822e7ce7d3SLiam R. Howlett if (!vma) 2983675eaca1SAlistair Popple goto unacct_fail; 29841da177e4SLinus Torvalds 2985bfd40eafSKirill A. Shutemov vma_set_anonymous(vma); 29861da177e4SLinus Torvalds vma->vm_start = addr; 29871da177e4SLinus Torvalds vma->vm_end = addr + len; 29882e7ce7d3SLiam R. Howlett vma->vm_pgoff = addr >> PAGE_SHIFT; 29891da177e4SLinus Torvalds vma->vm_flags = flags; 29903ed75eb8SColy Li vma->vm_page_prot = vm_get_page_prot(flags); 299192fed820SLiam R. Howlett if (vma_iter_store_gfp(vmi, vma, GFP_KERNEL)) 29922e7ce7d3SLiam R. Howlett goto mas_store_fail; 2993d4af56c5SLiam R. Howlett 29942e7ce7d3SLiam R. Howlett mm->map_count++; 29951da177e4SLinus Torvalds out: 29963af9e859SEric B Munson perf_event_mmap(vma); 29971da177e4SLinus Torvalds mm->total_vm += len >> PAGE_SHIFT; 299884638335SKonstantin Khlebnikov mm->data_vm += len >> PAGE_SHIFT; 2999128557ffSMichel Lespinasse if (flags & VM_LOCKED) 3000ba470de4SRik van Riel mm->locked_vm += (len >> PAGE_SHIFT); 3001d9104d1cSCyrill Gorcunov vma->vm_flags |= VM_SOFTDIRTY; 3002763ecb03SLiam R. Howlett validate_mm(mm); 30035d22fc25SLinus Torvalds return 0; 3004d4af56c5SLiam R. Howlett 30052e7ce7d3SLiam R. Howlett mas_store_fail: 3006d4af56c5SLiam R. Howlett vm_area_free(vma); 3007675eaca1SAlistair Popple unacct_fail: 30082e7ce7d3SLiam R. Howlett vm_unacct_memory(len >> PAGE_SHIFT); 30092e7ce7d3SLiam R. Howlett return -ENOMEM; 30101da177e4SLinus Torvalds } 30111da177e4SLinus Torvalds 3012bb177a73SMichal Hocko int vm_brk_flags(unsigned long addr, unsigned long request, unsigned long flags) 3013e4eb1ff6SLinus Torvalds { 3014e4eb1ff6SLinus Torvalds struct mm_struct *mm = current->mm; 30152e7ce7d3SLiam R. Howlett struct vm_area_struct *vma = NULL; 3016bb177a73SMichal Hocko unsigned long len; 30175d22fc25SLinus Torvalds int ret; 3018128557ffSMichel Lespinasse bool populate; 3019897ab3e0SMike Rapoport LIST_HEAD(uf); 302092fed820SLiam R. Howlett VMA_ITERATOR(vmi, mm, addr); 3021e4eb1ff6SLinus Torvalds 3022bb177a73SMichal Hocko len = PAGE_ALIGN(request); 3023bb177a73SMichal Hocko if (len < request) 3024bb177a73SMichal Hocko return -ENOMEM; 3025bb177a73SMichal Hocko if (!len) 3026bb177a73SMichal Hocko return 0; 3027bb177a73SMichal Hocko 3028d8ed45c5SMichel Lespinasse if (mmap_write_lock_killable(mm)) 30292d6c9282SMichal Hocko return -EINTR; 30302d6c9282SMichal Hocko 30312e7ce7d3SLiam R. Howlett /* Until we need other flags, refuse anything except VM_EXEC. */ 30322e7ce7d3SLiam R. Howlett if ((flags & (~VM_EXEC)) != 0) 30332e7ce7d3SLiam R. Howlett return -EINVAL; 30342e7ce7d3SLiam R. Howlett 30352e7ce7d3SLiam R. Howlett ret = check_brk_limits(addr, len); 30362e7ce7d3SLiam R. Howlett if (ret) 30372e7ce7d3SLiam R. Howlett goto limits_failed; 30382e7ce7d3SLiam R. Howlett 3039183654ceSLiam R. Howlett ret = do_vmi_munmap(&vmi, mm, addr, len, &uf, 0); 30402e7ce7d3SLiam R. Howlett if (ret) 30412e7ce7d3SLiam R. Howlett goto munmap_failed; 30422e7ce7d3SLiam R. Howlett 304392fed820SLiam R. Howlett vma = vma_prev(&vmi); 304492fed820SLiam R. Howlett ret = do_brk_flags(&vmi, vma, addr, len, flags); 3045128557ffSMichel Lespinasse populate = ((mm->def_flags & VM_LOCKED) != 0); 3046d8ed45c5SMichel Lespinasse mmap_write_unlock(mm); 3047897ab3e0SMike Rapoport userfaultfd_unmap_complete(mm, &uf); 30485d22fc25SLinus Torvalds if (populate && !ret) 3049128557ffSMichel Lespinasse mm_populate(addr, len); 3050e4eb1ff6SLinus Torvalds return ret; 30512e7ce7d3SLiam R. Howlett 30522e7ce7d3SLiam R. Howlett munmap_failed: 30532e7ce7d3SLiam R. Howlett limits_failed: 30542e7ce7d3SLiam R. Howlett mmap_write_unlock(mm); 30552e7ce7d3SLiam R. Howlett return ret; 3056e4eb1ff6SLinus Torvalds } 305716e72e9bSDenys Vlasenko EXPORT_SYMBOL(vm_brk_flags); 305816e72e9bSDenys Vlasenko 305916e72e9bSDenys Vlasenko int vm_brk(unsigned long addr, unsigned long len) 306016e72e9bSDenys Vlasenko { 306116e72e9bSDenys Vlasenko return vm_brk_flags(addr, len, 0); 306216e72e9bSDenys Vlasenko } 3063e4eb1ff6SLinus Torvalds EXPORT_SYMBOL(vm_brk); 30641da177e4SLinus Torvalds 30651da177e4SLinus Torvalds /* Release all mmaps. */ 30661da177e4SLinus Torvalds void exit_mmap(struct mm_struct *mm) 30671da177e4SLinus Torvalds { 3068d16dfc55SPeter Zijlstra struct mmu_gather tlb; 3069ba470de4SRik van Riel struct vm_area_struct *vma; 30701da177e4SLinus Torvalds unsigned long nr_accounted = 0; 3071763ecb03SLiam R. Howlett MA_STATE(mas, &mm->mm_mt, 0, 0); 3072763ecb03SLiam R. Howlett int count = 0; 30731da177e4SLinus Torvalds 3074d6dd61c8SJeremy Fitzhardinge /* mm's last user has gone, and its about to be pulled down */ 3075cddb8a5cSAndrea Arcangeli mmu_notifier_release(mm); 3076d6dd61c8SJeremy Fitzhardinge 3077bf3980c8SSuren Baghdasaryan mmap_read_lock(mm); 30789480c53eSJeremy Fitzhardinge arch_exit_mmap(mm); 30799480c53eSJeremy Fitzhardinge 3080763ecb03SLiam R. Howlett vma = mas_find(&mas, ULONG_MAX); 308164591e86SSuren Baghdasaryan if (!vma) { 308264591e86SSuren Baghdasaryan /* Can happen if dup_mmap() received an OOM */ 3083bf3980c8SSuren Baghdasaryan mmap_read_unlock(mm); 30849480c53eSJeremy Fitzhardinge return; 308564591e86SSuren Baghdasaryan } 30869480c53eSJeremy Fitzhardinge 30871da177e4SLinus Torvalds lru_add_drain(); 30881da177e4SLinus Torvalds flush_cache_mm(mm); 3089d8b45053SWill Deacon tlb_gather_mmu_fullmm(&tlb, mm); 3090901608d9SOleg Nesterov /* update_hiwater_rss(mm) here? but nobody should be looking */ 3091763ecb03SLiam R. Howlett /* Use ULONG_MAX here to ensure all VMAs in the mm are unmapped */ 3092763ecb03SLiam R. Howlett unmap_vmas(&tlb, &mm->mm_mt, vma, 0, ULONG_MAX); 3093bf3980c8SSuren Baghdasaryan mmap_read_unlock(mm); 3094bf3980c8SSuren Baghdasaryan 3095bf3980c8SSuren Baghdasaryan /* 3096bf3980c8SSuren Baghdasaryan * Set MMF_OOM_SKIP to hide this task from the oom killer/reaper 3097b3541d91SSuren Baghdasaryan * because the memory has been already freed. 3098bf3980c8SSuren Baghdasaryan */ 3099bf3980c8SSuren Baghdasaryan set_bit(MMF_OOM_SKIP, &mm->flags); 3100bf3980c8SSuren Baghdasaryan mmap_write_lock(mm); 3101763ecb03SLiam R. Howlett free_pgtables(&tlb, &mm->mm_mt, vma, FIRST_USER_ADDRESS, 3102763ecb03SLiam R. Howlett USER_PGTABLES_CEILING); 3103ae8eba8bSWill Deacon tlb_finish_mmu(&tlb); 31041da177e4SLinus Torvalds 3105763ecb03SLiam R. Howlett /* 3106763ecb03SLiam R. Howlett * Walk the list again, actually closing and freeing it, with preemption 3107763ecb03SLiam R. Howlett * enabled, without holding any MM locks besides the unreachable 3108763ecb03SLiam R. Howlett * mmap_write_lock. 3109763ecb03SLiam R. Howlett */ 3110763ecb03SLiam R. Howlett do { 31114f74d2c8SLinus Torvalds if (vma->vm_flags & VM_ACCOUNT) 31124f74d2c8SLinus Torvalds nr_accounted += vma_pages(vma); 3113763ecb03SLiam R. Howlett remove_vma(vma); 3114763ecb03SLiam R. Howlett count++; 31150a3b3c25SPaul E. McKenney cond_resched(); 3116763ecb03SLiam R. Howlett } while ((vma = mas_find(&mas, ULONG_MAX)) != NULL); 3117763ecb03SLiam R. Howlett 3118763ecb03SLiam R. Howlett BUG_ON(count != mm->map_count); 3119d4af56c5SLiam R. Howlett 3120d4af56c5SLiam R. Howlett trace_exit_mmap(mm); 3121d4af56c5SLiam R. Howlett __mt_destroy(&mm->mm_mt); 312264591e86SSuren Baghdasaryan mmap_write_unlock(mm); 31234f74d2c8SLinus Torvalds vm_unacct_memory(nr_accounted); 31241da177e4SLinus Torvalds } 31251da177e4SLinus Torvalds 31261da177e4SLinus Torvalds /* Insert vm structure into process list sorted by address 31271da177e4SLinus Torvalds * and into the inode's i_mmap tree. If vm_file is non-NULL 3128c8c06efaSDavidlohr Bueso * then i_mmap_rwsem is taken here. 31291da177e4SLinus Torvalds */ 31301da177e4SLinus Torvalds int insert_vm_struct(struct mm_struct *mm, struct vm_area_struct *vma) 31311da177e4SLinus Torvalds { 3132d4af56c5SLiam R. Howlett unsigned long charged = vma_pages(vma); 31331da177e4SLinus Torvalds 3134d4af56c5SLiam R. Howlett 3135d0601a50SLiam R. Howlett if (find_vma_intersection(mm, vma->vm_start, vma->vm_end)) 3136c9d13f5fSChen Gang return -ENOMEM; 3137d4af56c5SLiam R. Howlett 3138c9d13f5fSChen Gang if ((vma->vm_flags & VM_ACCOUNT) && 3139d4af56c5SLiam R. Howlett security_vm_enough_memory_mm(mm, charged)) 3140c9d13f5fSChen Gang return -ENOMEM; 3141c9d13f5fSChen Gang 31421da177e4SLinus Torvalds /* 31431da177e4SLinus Torvalds * The vm_pgoff of a purely anonymous vma should be irrelevant 31441da177e4SLinus Torvalds * until its first write fault, when page's anon_vma and index 31451da177e4SLinus Torvalds * are set. But now set the vm_pgoff it will almost certainly 31461da177e4SLinus Torvalds * end up with (unless mremap moves it elsewhere before that 31471da177e4SLinus Torvalds * first wfault), so /proc/pid/maps tells a consistent story. 31481da177e4SLinus Torvalds * 31491da177e4SLinus Torvalds * By setting it to reflect the virtual start address of the 31501da177e4SLinus Torvalds * vma, merges and splits can happen in a seamless way, just 31511da177e4SLinus Torvalds * using the existing file pgoff checks and manipulations. 31528332326eSLiao Pingfang * Similarly in do_mmap and in do_brk_flags. 31531da177e4SLinus Torvalds */ 31548a9cc3b5SOleg Nesterov if (vma_is_anonymous(vma)) { 31551da177e4SLinus Torvalds BUG_ON(vma->anon_vma); 31561da177e4SLinus Torvalds vma->vm_pgoff = vma->vm_start >> PAGE_SHIFT; 31571da177e4SLinus Torvalds } 31582b144498SSrikar Dronamraju 3159763ecb03SLiam R. Howlett if (vma_link(mm, vma)) { 3160d4af56c5SLiam R. Howlett vm_unacct_memory(charged); 3161d4af56c5SLiam R. Howlett return -ENOMEM; 3162d4af56c5SLiam R. Howlett } 3163d4af56c5SLiam R. Howlett 31641da177e4SLinus Torvalds return 0; 31651da177e4SLinus Torvalds } 31661da177e4SLinus Torvalds 31671da177e4SLinus Torvalds /* 31681da177e4SLinus Torvalds * Copy the vma structure to a new location in the same mm, 31691da177e4SLinus Torvalds * prior to moving page table entries, to effect an mremap move. 31701da177e4SLinus Torvalds */ 31711da177e4SLinus Torvalds struct vm_area_struct *copy_vma(struct vm_area_struct **vmap, 317238a76013SMichel Lespinasse unsigned long addr, unsigned long len, pgoff_t pgoff, 317338a76013SMichel Lespinasse bool *need_rmap_locks) 31741da177e4SLinus Torvalds { 31751da177e4SLinus Torvalds struct vm_area_struct *vma = *vmap; 31761da177e4SLinus Torvalds unsigned long vma_start = vma->vm_start; 31771da177e4SLinus Torvalds struct mm_struct *mm = vma->vm_mm; 31781da177e4SLinus Torvalds struct vm_area_struct *new_vma, *prev; 3179948f017bSAndrea Arcangeli bool faulted_in_anon_vma = true; 3180076f16bfSLiam R. Howlett VMA_ITERATOR(vmi, mm, addr); 31811da177e4SLinus Torvalds 3182d4af56c5SLiam R. Howlett validate_mm_mt(mm); 31831da177e4SLinus Torvalds /* 31841da177e4SLinus Torvalds * If anonymous vma has not yet been faulted, update new pgoff 31851da177e4SLinus Torvalds * to match new location, to increase its chance of merging. 31861da177e4SLinus Torvalds */ 3187ce75799bSOleg Nesterov if (unlikely(vma_is_anonymous(vma) && !vma->anon_vma)) { 31881da177e4SLinus Torvalds pgoff = addr >> PAGE_SHIFT; 3189948f017bSAndrea Arcangeli faulted_in_anon_vma = false; 3190948f017bSAndrea Arcangeli } 31911da177e4SLinus Torvalds 3192763ecb03SLiam R. Howlett new_vma = find_vma_prev(mm, addr, &prev); 3193763ecb03SLiam R. Howlett if (new_vma && new_vma->vm_start < addr + len) 31946597d783SHugh Dickins return NULL; /* should never get here */ 3195524e00b3SLiam R. Howlett 31969760ebffSLiam R. Howlett new_vma = vma_merge(&vmi, mm, prev, addr, addr + len, vma->vm_flags, 319719a809afSAndrea Arcangeli vma->anon_vma, vma->vm_file, pgoff, vma_policy(vma), 31985c26f6acSSuren Baghdasaryan vma->vm_userfaultfd_ctx, anon_vma_name(vma)); 31991da177e4SLinus Torvalds if (new_vma) { 32001da177e4SLinus Torvalds /* 32011da177e4SLinus Torvalds * Source vma may have been merged into new_vma 32021da177e4SLinus Torvalds */ 3203948f017bSAndrea Arcangeli if (unlikely(vma_start >= new_vma->vm_start && 3204948f017bSAndrea Arcangeli vma_start < new_vma->vm_end)) { 3205948f017bSAndrea Arcangeli /* 3206948f017bSAndrea Arcangeli * The only way we can get a vma_merge with 3207948f017bSAndrea Arcangeli * self during an mremap is if the vma hasn't 3208948f017bSAndrea Arcangeli * been faulted in yet and we were allowed to 3209948f017bSAndrea Arcangeli * reset the dst vma->vm_pgoff to the 3210948f017bSAndrea Arcangeli * destination address of the mremap to allow 3211948f017bSAndrea Arcangeli * the merge to happen. mremap must change the 3212948f017bSAndrea Arcangeli * vm_pgoff linearity between src and dst vmas 3213948f017bSAndrea Arcangeli * (in turn preventing a vma_merge) to be 3214948f017bSAndrea Arcangeli * safe. It is only safe to keep the vm_pgoff 3215948f017bSAndrea Arcangeli * linear if there are no pages mapped yet. 3216948f017bSAndrea Arcangeli */ 321781d1b09cSSasha Levin VM_BUG_ON_VMA(faulted_in_anon_vma, new_vma); 321838a76013SMichel Lespinasse *vmap = vma = new_vma; 3219108d6642SMichel Lespinasse } 322038a76013SMichel Lespinasse *need_rmap_locks = (new_vma->vm_pgoff <= vma->vm_pgoff); 32211da177e4SLinus Torvalds } else { 32223928d4f5SLinus Torvalds new_vma = vm_area_dup(vma); 3223e3975891SChen Gang if (!new_vma) 3224e3975891SChen Gang goto out; 32251da177e4SLinus Torvalds new_vma->vm_start = addr; 32261da177e4SLinus Torvalds new_vma->vm_end = addr + len; 32271da177e4SLinus Torvalds new_vma->vm_pgoff = pgoff; 3228ef0855d3SOleg Nesterov if (vma_dup_policy(vma, new_vma)) 3229523d4e20SMichel Lespinasse goto out_free_vma; 3230523d4e20SMichel Lespinasse if (anon_vma_clone(new_vma, vma)) 3231523d4e20SMichel Lespinasse goto out_free_mempol; 3232e9714acfSKonstantin Khlebnikov if (new_vma->vm_file) 32331da177e4SLinus Torvalds get_file(new_vma->vm_file); 32341da177e4SLinus Torvalds if (new_vma->vm_ops && new_vma->vm_ops->open) 32351da177e4SLinus Torvalds new_vma->vm_ops->open(new_vma); 3236763ecb03SLiam R. Howlett if (vma_link(mm, new_vma)) 3237524e00b3SLiam R. Howlett goto out_vma_link; 323838a76013SMichel Lespinasse *need_rmap_locks = false; 32391da177e4SLinus Torvalds } 3240d4af56c5SLiam R. Howlett validate_mm_mt(mm); 32411da177e4SLinus Torvalds return new_vma; 32425beb4930SRik van Riel 3243524e00b3SLiam R. Howlett out_vma_link: 3244524e00b3SLiam R. Howlett if (new_vma->vm_ops && new_vma->vm_ops->close) 3245524e00b3SLiam R. Howlett new_vma->vm_ops->close(new_vma); 324692b73996SLiam Howlett 324792b73996SLiam Howlett if (new_vma->vm_file) 324892b73996SLiam Howlett fput(new_vma->vm_file); 324992b73996SLiam Howlett 325092b73996SLiam Howlett unlink_anon_vmas(new_vma); 32515beb4930SRik van Riel out_free_mempol: 3252ef0855d3SOleg Nesterov mpol_put(vma_policy(new_vma)); 32535beb4930SRik van Riel out_free_vma: 32543928d4f5SLinus Torvalds vm_area_free(new_vma); 3255e3975891SChen Gang out: 3256d4af56c5SLiam R. Howlett validate_mm_mt(mm); 32575beb4930SRik van Riel return NULL; 32581da177e4SLinus Torvalds } 3259119f657cSakpm@osdl.org 3260119f657cSakpm@osdl.org /* 3261119f657cSakpm@osdl.org * Return true if the calling process may expand its vm space by the passed 3262119f657cSakpm@osdl.org * number of pages 3263119f657cSakpm@osdl.org */ 326484638335SKonstantin Khlebnikov bool may_expand_vm(struct mm_struct *mm, vm_flags_t flags, unsigned long npages) 3265119f657cSakpm@osdl.org { 326684638335SKonstantin Khlebnikov if (mm->total_vm + npages > rlimit(RLIMIT_AS) >> PAGE_SHIFT) 326784638335SKonstantin Khlebnikov return false; 3268119f657cSakpm@osdl.org 3269d977d56cSKonstantin Khlebnikov if (is_data_mapping(flags) && 3270d977d56cSKonstantin Khlebnikov mm->data_vm + npages > rlimit(RLIMIT_DATA) >> PAGE_SHIFT) { 3271f4fcd558SKonstantin Khlebnikov /* Workaround for Valgrind */ 3272f4fcd558SKonstantin Khlebnikov if (rlimit(RLIMIT_DATA) == 0 && 3273f4fcd558SKonstantin Khlebnikov mm->data_vm + npages <= rlimit_max(RLIMIT_DATA) >> PAGE_SHIFT) 3274f4fcd558SKonstantin Khlebnikov return true; 327557a7702bSDavid Woodhouse 327657a7702bSDavid Woodhouse pr_warn_once("%s (%d): VmData %lu exceed data ulimit %lu. Update limits%s.\n", 3277d977d56cSKonstantin Khlebnikov current->comm, current->pid, 3278d977d56cSKonstantin Khlebnikov (mm->data_vm + npages) << PAGE_SHIFT, 327957a7702bSDavid Woodhouse rlimit(RLIMIT_DATA), 328057a7702bSDavid Woodhouse ignore_rlimit_data ? "" : " or use boot option ignore_rlimit_data"); 328157a7702bSDavid Woodhouse 328257a7702bSDavid Woodhouse if (!ignore_rlimit_data) 3283d977d56cSKonstantin Khlebnikov return false; 3284d977d56cSKonstantin Khlebnikov } 3285119f657cSakpm@osdl.org 328684638335SKonstantin Khlebnikov return true; 328784638335SKonstantin Khlebnikov } 328884638335SKonstantin Khlebnikov 328984638335SKonstantin Khlebnikov void vm_stat_account(struct mm_struct *mm, vm_flags_t flags, long npages) 329084638335SKonstantin Khlebnikov { 32917866076bSPeng Liu WRITE_ONCE(mm->total_vm, READ_ONCE(mm->total_vm)+npages); 329284638335SKonstantin Khlebnikov 3293d977d56cSKonstantin Khlebnikov if (is_exec_mapping(flags)) 329484638335SKonstantin Khlebnikov mm->exec_vm += npages; 3295d977d56cSKonstantin Khlebnikov else if (is_stack_mapping(flags)) 329684638335SKonstantin Khlebnikov mm->stack_vm += npages; 3297d977d56cSKonstantin Khlebnikov else if (is_data_mapping(flags)) 329884638335SKonstantin Khlebnikov mm->data_vm += npages; 3299119f657cSakpm@osdl.org } 3300fa5dc22fSRoland McGrath 3301b3ec9f33SSouptick Joarder static vm_fault_t special_mapping_fault(struct vm_fault *vmf); 3302a62c34bdSAndy Lutomirski 3303a62c34bdSAndy Lutomirski /* 3304a62c34bdSAndy Lutomirski * Having a close hook prevents vma merging regardless of flags. 3305a62c34bdSAndy Lutomirski */ 3306a62c34bdSAndy Lutomirski static void special_mapping_close(struct vm_area_struct *vma) 3307a62c34bdSAndy Lutomirski { 3308a62c34bdSAndy Lutomirski } 3309a62c34bdSAndy Lutomirski 3310a62c34bdSAndy Lutomirski static const char *special_mapping_name(struct vm_area_struct *vma) 3311a62c34bdSAndy Lutomirski { 3312a62c34bdSAndy Lutomirski return ((struct vm_special_mapping *)vma->vm_private_data)->name; 3313a62c34bdSAndy Lutomirski } 3314a62c34bdSAndy Lutomirski 331514d07113SBrian Geffon static int special_mapping_mremap(struct vm_area_struct *new_vma) 3316b059a453SDmitry Safonov { 3317b059a453SDmitry Safonov struct vm_special_mapping *sm = new_vma->vm_private_data; 3318b059a453SDmitry Safonov 3319280e87e9SDmitry Safonov if (WARN_ON_ONCE(current->mm != new_vma->vm_mm)) 3320280e87e9SDmitry Safonov return -EFAULT; 3321280e87e9SDmitry Safonov 3322b059a453SDmitry Safonov if (sm->mremap) 3323b059a453SDmitry Safonov return sm->mremap(sm, new_vma); 3324280e87e9SDmitry Safonov 3325b059a453SDmitry Safonov return 0; 3326b059a453SDmitry Safonov } 3327b059a453SDmitry Safonov 3328871402e0SDmitry Safonov static int special_mapping_split(struct vm_area_struct *vma, unsigned long addr) 3329871402e0SDmitry Safonov { 3330871402e0SDmitry Safonov /* 3331871402e0SDmitry Safonov * Forbid splitting special mappings - kernel has expectations over 3332871402e0SDmitry Safonov * the number of pages in mapping. Together with VM_DONTEXPAND 3333871402e0SDmitry Safonov * the size of vma should stay the same over the special mapping's 3334871402e0SDmitry Safonov * lifetime. 3335871402e0SDmitry Safonov */ 3336871402e0SDmitry Safonov return -EINVAL; 3337871402e0SDmitry Safonov } 3338871402e0SDmitry Safonov 3339a62c34bdSAndy Lutomirski static const struct vm_operations_struct special_mapping_vmops = { 3340a62c34bdSAndy Lutomirski .close = special_mapping_close, 3341a62c34bdSAndy Lutomirski .fault = special_mapping_fault, 3342b059a453SDmitry Safonov .mremap = special_mapping_mremap, 3343a62c34bdSAndy Lutomirski .name = special_mapping_name, 3344af34ebebSDmitry Safonov /* vDSO code relies that VVAR can't be accessed remotely */ 3345af34ebebSDmitry Safonov .access = NULL, 3346871402e0SDmitry Safonov .may_split = special_mapping_split, 3347a62c34bdSAndy Lutomirski }; 3348a62c34bdSAndy Lutomirski 3349a62c34bdSAndy Lutomirski static const struct vm_operations_struct legacy_special_mapping_vmops = { 3350a62c34bdSAndy Lutomirski .close = special_mapping_close, 3351a62c34bdSAndy Lutomirski .fault = special_mapping_fault, 3352a62c34bdSAndy Lutomirski }; 3353fa5dc22fSRoland McGrath 3354b3ec9f33SSouptick Joarder static vm_fault_t special_mapping_fault(struct vm_fault *vmf) 3355fa5dc22fSRoland McGrath { 335611bac800SDave Jiang struct vm_area_struct *vma = vmf->vma; 3357b1d0e4f5SNick Piggin pgoff_t pgoff; 3358fa5dc22fSRoland McGrath struct page **pages; 3359fa5dc22fSRoland McGrath 3360f872f540SAndy Lutomirski if (vma->vm_ops == &legacy_special_mapping_vmops) { 3361a62c34bdSAndy Lutomirski pages = vma->vm_private_data; 3362f872f540SAndy Lutomirski } else { 3363f872f540SAndy Lutomirski struct vm_special_mapping *sm = vma->vm_private_data; 3364f872f540SAndy Lutomirski 3365f872f540SAndy Lutomirski if (sm->fault) 336611bac800SDave Jiang return sm->fault(sm, vmf->vma, vmf); 3367f872f540SAndy Lutomirski 3368f872f540SAndy Lutomirski pages = sm->pages; 3369f872f540SAndy Lutomirski } 3370a62c34bdSAndy Lutomirski 33718a9cc3b5SOleg Nesterov for (pgoff = vmf->pgoff; pgoff && *pages; ++pages) 3372b1d0e4f5SNick Piggin pgoff--; 3373fa5dc22fSRoland McGrath 3374fa5dc22fSRoland McGrath if (*pages) { 3375fa5dc22fSRoland McGrath struct page *page = *pages; 3376fa5dc22fSRoland McGrath get_page(page); 3377b1d0e4f5SNick Piggin vmf->page = page; 3378b1d0e4f5SNick Piggin return 0; 3379fa5dc22fSRoland McGrath } 3380fa5dc22fSRoland McGrath 3381b1d0e4f5SNick Piggin return VM_FAULT_SIGBUS; 3382fa5dc22fSRoland McGrath } 3383fa5dc22fSRoland McGrath 3384a62c34bdSAndy Lutomirski static struct vm_area_struct *__install_special_mapping( 3385a62c34bdSAndy Lutomirski struct mm_struct *mm, 3386fa5dc22fSRoland McGrath unsigned long addr, unsigned long len, 338727f28b97SChen Gang unsigned long vm_flags, void *priv, 338827f28b97SChen Gang const struct vm_operations_struct *ops) 3389fa5dc22fSRoland McGrath { 3390462e635eSTavis Ormandy int ret; 3391fa5dc22fSRoland McGrath struct vm_area_struct *vma; 3392fa5dc22fSRoland McGrath 3393d4af56c5SLiam R. Howlett validate_mm_mt(mm); 3394490fc053SLinus Torvalds vma = vm_area_alloc(mm); 3395fa5dc22fSRoland McGrath if (unlikely(vma == NULL)) 33963935ed6aSStefani Seibold return ERR_PTR(-ENOMEM); 3397fa5dc22fSRoland McGrath 3398fa5dc22fSRoland McGrath vma->vm_start = addr; 3399fa5dc22fSRoland McGrath vma->vm_end = addr + len; 3400fa5dc22fSRoland McGrath 3401d9104d1cSCyrill Gorcunov vma->vm_flags = vm_flags | mm->def_flags | VM_DONTEXPAND | VM_SOFTDIRTY; 34021fc09228SHugh Dickins vma->vm_flags &= VM_LOCKED_CLEAR_MASK; 34033ed75eb8SColy Li vma->vm_page_prot = vm_get_page_prot(vma->vm_flags); 3404fa5dc22fSRoland McGrath 3405a62c34bdSAndy Lutomirski vma->vm_ops = ops; 3406a62c34bdSAndy Lutomirski vma->vm_private_data = priv; 3407fa5dc22fSRoland McGrath 3408462e635eSTavis Ormandy ret = insert_vm_struct(mm, vma); 3409462e635eSTavis Ormandy if (ret) 3410462e635eSTavis Ormandy goto out; 3411fa5dc22fSRoland McGrath 341284638335SKonstantin Khlebnikov vm_stat_account(mm, vma->vm_flags, len >> PAGE_SHIFT); 3413fa5dc22fSRoland McGrath 3414cdd6c482SIngo Molnar perf_event_mmap(vma); 3415089dd79dSPeter Zijlstra 3416d4af56c5SLiam R. Howlett validate_mm_mt(mm); 34173935ed6aSStefani Seibold return vma; 3418462e635eSTavis Ormandy 3419462e635eSTavis Ormandy out: 34203928d4f5SLinus Torvalds vm_area_free(vma); 3421d4af56c5SLiam R. Howlett validate_mm_mt(mm); 34223935ed6aSStefani Seibold return ERR_PTR(ret); 34233935ed6aSStefani Seibold } 34243935ed6aSStefani Seibold 34252eefd878SDmitry Safonov bool vma_is_special_mapping(const struct vm_area_struct *vma, 34262eefd878SDmitry Safonov const struct vm_special_mapping *sm) 34272eefd878SDmitry Safonov { 34282eefd878SDmitry Safonov return vma->vm_private_data == sm && 34292eefd878SDmitry Safonov (vma->vm_ops == &special_mapping_vmops || 34302eefd878SDmitry Safonov vma->vm_ops == &legacy_special_mapping_vmops); 34312eefd878SDmitry Safonov } 34322eefd878SDmitry Safonov 3433a62c34bdSAndy Lutomirski /* 3434c1e8d7c6SMichel Lespinasse * Called with mm->mmap_lock held for writing. 3435a62c34bdSAndy Lutomirski * Insert a new vma covering the given region, with the given flags. 3436a62c34bdSAndy Lutomirski * Its pages are supplied by the given array of struct page *. 3437a62c34bdSAndy Lutomirski * The array can be shorter than len >> PAGE_SHIFT if it's null-terminated. 3438a62c34bdSAndy Lutomirski * The region past the last page supplied will always produce SIGBUS. 3439a62c34bdSAndy Lutomirski * The array pointer and the pages it points to are assumed to stay alive 3440a62c34bdSAndy Lutomirski * for as long as this mapping might exist. 3441a62c34bdSAndy Lutomirski */ 3442a62c34bdSAndy Lutomirski struct vm_area_struct *_install_special_mapping( 3443a62c34bdSAndy Lutomirski struct mm_struct *mm, 3444a62c34bdSAndy Lutomirski unsigned long addr, unsigned long len, 3445a62c34bdSAndy Lutomirski unsigned long vm_flags, const struct vm_special_mapping *spec) 3446a62c34bdSAndy Lutomirski { 344727f28b97SChen Gang return __install_special_mapping(mm, addr, len, vm_flags, (void *)spec, 344827f28b97SChen Gang &special_mapping_vmops); 3449a62c34bdSAndy Lutomirski } 3450a62c34bdSAndy Lutomirski 34513935ed6aSStefani Seibold int install_special_mapping(struct mm_struct *mm, 34523935ed6aSStefani Seibold unsigned long addr, unsigned long len, 34533935ed6aSStefani Seibold unsigned long vm_flags, struct page **pages) 34543935ed6aSStefani Seibold { 3455a62c34bdSAndy Lutomirski struct vm_area_struct *vma = __install_special_mapping( 345627f28b97SChen Gang mm, addr, len, vm_flags, (void *)pages, 345727f28b97SChen Gang &legacy_special_mapping_vmops); 34583935ed6aSStefani Seibold 345914bd5b45SDuan Jiong return PTR_ERR_OR_ZERO(vma); 3460fa5dc22fSRoland McGrath } 34617906d00cSAndrea Arcangeli 34627906d00cSAndrea Arcangeli static DEFINE_MUTEX(mm_all_locks_mutex); 34637906d00cSAndrea Arcangeli 3464454ed842SPeter Zijlstra static void vm_lock_anon_vma(struct mm_struct *mm, struct anon_vma *anon_vma) 34657906d00cSAndrea Arcangeli { 3466f808c13fSDavidlohr Bueso if (!test_bit(0, (unsigned long *) &anon_vma->root->rb_root.rb_root.rb_node)) { 34677906d00cSAndrea Arcangeli /* 34687906d00cSAndrea Arcangeli * The LSB of head.next can't change from under us 34697906d00cSAndrea Arcangeli * because we hold the mm_all_locks_mutex. 34707906d00cSAndrea Arcangeli */ 3471da1c55f1SMichel Lespinasse down_write_nest_lock(&anon_vma->root->rwsem, &mm->mmap_lock); 34727906d00cSAndrea Arcangeli /* 34737906d00cSAndrea Arcangeli * We can safely modify head.next after taking the 34745a505085SIngo Molnar * anon_vma->root->rwsem. If some other vma in this mm shares 34757906d00cSAndrea Arcangeli * the same anon_vma we won't take it again. 34767906d00cSAndrea Arcangeli * 34777906d00cSAndrea Arcangeli * No need of atomic instructions here, head.next 34787906d00cSAndrea Arcangeli * can't change from under us thanks to the 34795a505085SIngo Molnar * anon_vma->root->rwsem. 34807906d00cSAndrea Arcangeli */ 34817906d00cSAndrea Arcangeli if (__test_and_set_bit(0, (unsigned long *) 3482f808c13fSDavidlohr Bueso &anon_vma->root->rb_root.rb_root.rb_node)) 34837906d00cSAndrea Arcangeli BUG(); 34847906d00cSAndrea Arcangeli } 34857906d00cSAndrea Arcangeli } 34867906d00cSAndrea Arcangeli 3487454ed842SPeter Zijlstra static void vm_lock_mapping(struct mm_struct *mm, struct address_space *mapping) 34887906d00cSAndrea Arcangeli { 34897906d00cSAndrea Arcangeli if (!test_bit(AS_MM_ALL_LOCKS, &mapping->flags)) { 34907906d00cSAndrea Arcangeli /* 34917906d00cSAndrea Arcangeli * AS_MM_ALL_LOCKS can't change from under us because 34927906d00cSAndrea Arcangeli * we hold the mm_all_locks_mutex. 34937906d00cSAndrea Arcangeli * 34947906d00cSAndrea Arcangeli * Operations on ->flags have to be atomic because 34957906d00cSAndrea Arcangeli * even if AS_MM_ALL_LOCKS is stable thanks to the 34967906d00cSAndrea Arcangeli * mm_all_locks_mutex, there may be other cpus 34977906d00cSAndrea Arcangeli * changing other bitflags in parallel to us. 34987906d00cSAndrea Arcangeli */ 34997906d00cSAndrea Arcangeli if (test_and_set_bit(AS_MM_ALL_LOCKS, &mapping->flags)) 35007906d00cSAndrea Arcangeli BUG(); 3501da1c55f1SMichel Lespinasse down_write_nest_lock(&mapping->i_mmap_rwsem, &mm->mmap_lock); 35027906d00cSAndrea Arcangeli } 35037906d00cSAndrea Arcangeli } 35047906d00cSAndrea Arcangeli 35057906d00cSAndrea Arcangeli /* 35067906d00cSAndrea Arcangeli * This operation locks against the VM for all pte/vma/mm related 35077906d00cSAndrea Arcangeli * operations that could ever happen on a certain mm. This includes 35087906d00cSAndrea Arcangeli * vmtruncate, try_to_unmap, and all page faults. 35097906d00cSAndrea Arcangeli * 3510c1e8d7c6SMichel Lespinasse * The caller must take the mmap_lock in write mode before calling 35117906d00cSAndrea Arcangeli * mm_take_all_locks(). The caller isn't allowed to release the 3512c1e8d7c6SMichel Lespinasse * mmap_lock until mm_drop_all_locks() returns. 35137906d00cSAndrea Arcangeli * 3514c1e8d7c6SMichel Lespinasse * mmap_lock in write mode is required in order to block all operations 35157906d00cSAndrea Arcangeli * that could modify pagetables and free pages without need of 351627ba0644SKirill A. Shutemov * altering the vma layout. It's also needed in write mode to avoid new 35177906d00cSAndrea Arcangeli * anon_vmas to be associated with existing vmas. 35187906d00cSAndrea Arcangeli * 35197906d00cSAndrea Arcangeli * A single task can't take more than one mm_take_all_locks() in a row 35207906d00cSAndrea Arcangeli * or it would deadlock. 35217906d00cSAndrea Arcangeli * 3522bf181b9fSMichel Lespinasse * The LSB in anon_vma->rb_root.rb_node and the AS_MM_ALL_LOCKS bitflag in 35237906d00cSAndrea Arcangeli * mapping->flags avoid to take the same lock twice, if more than one 35247906d00cSAndrea Arcangeli * vma in this mm is backed by the same anon_vma or address_space. 35257906d00cSAndrea Arcangeli * 352688f306b6SKirill A. Shutemov * We take locks in following order, accordingly to comment at beginning 352788f306b6SKirill A. Shutemov * of mm/rmap.c: 352888f306b6SKirill A. Shutemov * - all hugetlbfs_i_mmap_rwsem_key locks (aka mapping->i_mmap_rwsem for 352988f306b6SKirill A. Shutemov * hugetlb mapping); 353088f306b6SKirill A. Shutemov * - all i_mmap_rwsem locks; 353188f306b6SKirill A. Shutemov * - all anon_vma->rwseml 353288f306b6SKirill A. Shutemov * 353388f306b6SKirill A. Shutemov * We can take all locks within these types randomly because the VM code 353488f306b6SKirill A. Shutemov * doesn't nest them and we protected from parallel mm_take_all_locks() by 353588f306b6SKirill A. Shutemov * mm_all_locks_mutex. 35367906d00cSAndrea Arcangeli * 35377906d00cSAndrea Arcangeli * mm_take_all_locks() and mm_drop_all_locks are expensive operations 35387906d00cSAndrea Arcangeli * that may have to take thousand of locks. 35397906d00cSAndrea Arcangeli * 35407906d00cSAndrea Arcangeli * mm_take_all_locks() can fail if it's interrupted by signals. 35417906d00cSAndrea Arcangeli */ 35427906d00cSAndrea Arcangeli int mm_take_all_locks(struct mm_struct *mm) 35437906d00cSAndrea Arcangeli { 35447906d00cSAndrea Arcangeli struct vm_area_struct *vma; 35455beb4930SRik van Riel struct anon_vma_chain *avc; 3546763ecb03SLiam R. Howlett MA_STATE(mas, &mm->mm_mt, 0, 0); 35477906d00cSAndrea Arcangeli 3548325bca1fSRolf Eike Beer mmap_assert_write_locked(mm); 35497906d00cSAndrea Arcangeli 35507906d00cSAndrea Arcangeli mutex_lock(&mm_all_locks_mutex); 35517906d00cSAndrea Arcangeli 3552763ecb03SLiam R. Howlett mas_for_each(&mas, vma, ULONG_MAX) { 35537906d00cSAndrea Arcangeli if (signal_pending(current)) 35547906d00cSAndrea Arcangeli goto out_unlock; 355588f306b6SKirill A. Shutemov if (vma->vm_file && vma->vm_file->f_mapping && 355688f306b6SKirill A. Shutemov is_vm_hugetlb_page(vma)) 355788f306b6SKirill A. Shutemov vm_lock_mapping(mm, vma->vm_file->f_mapping); 355888f306b6SKirill A. Shutemov } 355988f306b6SKirill A. Shutemov 3560763ecb03SLiam R. Howlett mas_set(&mas, 0); 3561763ecb03SLiam R. Howlett mas_for_each(&mas, vma, ULONG_MAX) { 356288f306b6SKirill A. Shutemov if (signal_pending(current)) 356388f306b6SKirill A. Shutemov goto out_unlock; 356488f306b6SKirill A. Shutemov if (vma->vm_file && vma->vm_file->f_mapping && 356588f306b6SKirill A. Shutemov !is_vm_hugetlb_page(vma)) 3566454ed842SPeter Zijlstra vm_lock_mapping(mm, vma->vm_file->f_mapping); 35677906d00cSAndrea Arcangeli } 35687cd5a02fSPeter Zijlstra 3569763ecb03SLiam R. Howlett mas_set(&mas, 0); 3570763ecb03SLiam R. Howlett mas_for_each(&mas, vma, ULONG_MAX) { 35717cd5a02fSPeter Zijlstra if (signal_pending(current)) 35727cd5a02fSPeter Zijlstra goto out_unlock; 35737cd5a02fSPeter Zijlstra if (vma->anon_vma) 35745beb4930SRik van Riel list_for_each_entry(avc, &vma->anon_vma_chain, same_vma) 35755beb4930SRik van Riel vm_lock_anon_vma(mm, avc->anon_vma); 35767cd5a02fSPeter Zijlstra } 35777cd5a02fSPeter Zijlstra 3578584cff54SKautuk Consul return 0; 35797906d00cSAndrea Arcangeli 35807906d00cSAndrea Arcangeli out_unlock: 35817906d00cSAndrea Arcangeli mm_drop_all_locks(mm); 3582584cff54SKautuk Consul return -EINTR; 35837906d00cSAndrea Arcangeli } 35847906d00cSAndrea Arcangeli 35857906d00cSAndrea Arcangeli static void vm_unlock_anon_vma(struct anon_vma *anon_vma) 35867906d00cSAndrea Arcangeli { 3587f808c13fSDavidlohr Bueso if (test_bit(0, (unsigned long *) &anon_vma->root->rb_root.rb_root.rb_node)) { 35887906d00cSAndrea Arcangeli /* 35897906d00cSAndrea Arcangeli * The LSB of head.next can't change to 0 from under 35907906d00cSAndrea Arcangeli * us because we hold the mm_all_locks_mutex. 35917906d00cSAndrea Arcangeli * 35927906d00cSAndrea Arcangeli * We must however clear the bitflag before unlocking 3593bf181b9fSMichel Lespinasse * the vma so the users using the anon_vma->rb_root will 35947906d00cSAndrea Arcangeli * never see our bitflag. 35957906d00cSAndrea Arcangeli * 35967906d00cSAndrea Arcangeli * No need of atomic instructions here, head.next 35977906d00cSAndrea Arcangeli * can't change from under us until we release the 35985a505085SIngo Molnar * anon_vma->root->rwsem. 35997906d00cSAndrea Arcangeli */ 36007906d00cSAndrea Arcangeli if (!__test_and_clear_bit(0, (unsigned long *) 3601f808c13fSDavidlohr Bueso &anon_vma->root->rb_root.rb_root.rb_node)) 36027906d00cSAndrea Arcangeli BUG(); 360308b52706SKonstantin Khlebnikov anon_vma_unlock_write(anon_vma); 36047906d00cSAndrea Arcangeli } 36057906d00cSAndrea Arcangeli } 36067906d00cSAndrea Arcangeli 36077906d00cSAndrea Arcangeli static void vm_unlock_mapping(struct address_space *mapping) 36087906d00cSAndrea Arcangeli { 36097906d00cSAndrea Arcangeli if (test_bit(AS_MM_ALL_LOCKS, &mapping->flags)) { 36107906d00cSAndrea Arcangeli /* 36117906d00cSAndrea Arcangeli * AS_MM_ALL_LOCKS can't change to 0 from under us 36127906d00cSAndrea Arcangeli * because we hold the mm_all_locks_mutex. 36137906d00cSAndrea Arcangeli */ 361483cde9e8SDavidlohr Bueso i_mmap_unlock_write(mapping); 36157906d00cSAndrea Arcangeli if (!test_and_clear_bit(AS_MM_ALL_LOCKS, 36167906d00cSAndrea Arcangeli &mapping->flags)) 36177906d00cSAndrea Arcangeli BUG(); 36187906d00cSAndrea Arcangeli } 36197906d00cSAndrea Arcangeli } 36207906d00cSAndrea Arcangeli 36217906d00cSAndrea Arcangeli /* 3622c1e8d7c6SMichel Lespinasse * The mmap_lock cannot be released by the caller until 36237906d00cSAndrea Arcangeli * mm_drop_all_locks() returns. 36247906d00cSAndrea Arcangeli */ 36257906d00cSAndrea Arcangeli void mm_drop_all_locks(struct mm_struct *mm) 36267906d00cSAndrea Arcangeli { 36277906d00cSAndrea Arcangeli struct vm_area_struct *vma; 36285beb4930SRik van Riel struct anon_vma_chain *avc; 3629763ecb03SLiam R. Howlett MA_STATE(mas, &mm->mm_mt, 0, 0); 36307906d00cSAndrea Arcangeli 3631325bca1fSRolf Eike Beer mmap_assert_write_locked(mm); 36327906d00cSAndrea Arcangeli BUG_ON(!mutex_is_locked(&mm_all_locks_mutex)); 36337906d00cSAndrea Arcangeli 3634763ecb03SLiam R. Howlett mas_for_each(&mas, vma, ULONG_MAX) { 36357906d00cSAndrea Arcangeli if (vma->anon_vma) 36365beb4930SRik van Riel list_for_each_entry(avc, &vma->anon_vma_chain, same_vma) 36375beb4930SRik van Riel vm_unlock_anon_vma(avc->anon_vma); 36387906d00cSAndrea Arcangeli if (vma->vm_file && vma->vm_file->f_mapping) 36397906d00cSAndrea Arcangeli vm_unlock_mapping(vma->vm_file->f_mapping); 36407906d00cSAndrea Arcangeli } 36417906d00cSAndrea Arcangeli 36427906d00cSAndrea Arcangeli mutex_unlock(&mm_all_locks_mutex); 36437906d00cSAndrea Arcangeli } 36448feae131SDavid Howells 36458feae131SDavid Howells /* 36463edf41d8Sseokhoon.yoon * initialise the percpu counter for VM 36478feae131SDavid Howells */ 36488feae131SDavid Howells void __init mmap_init(void) 36498feae131SDavid Howells { 365000a62ce9SKOSAKI Motohiro int ret; 365100a62ce9SKOSAKI Motohiro 3652908c7f19STejun Heo ret = percpu_counter_init(&vm_committed_as, 0, GFP_KERNEL); 365300a62ce9SKOSAKI Motohiro VM_BUG_ON(ret); 36548feae131SDavid Howells } 3655c9b1d098SAndrew Shewmaker 3656c9b1d098SAndrew Shewmaker /* 3657c9b1d098SAndrew Shewmaker * Initialise sysctl_user_reserve_kbytes. 3658c9b1d098SAndrew Shewmaker * 3659c9b1d098SAndrew Shewmaker * This is intended to prevent a user from starting a single memory hogging 3660c9b1d098SAndrew Shewmaker * process, such that they cannot recover (kill the hog) in OVERCOMMIT_NEVER 3661c9b1d098SAndrew Shewmaker * mode. 3662c9b1d098SAndrew Shewmaker * 3663c9b1d098SAndrew Shewmaker * The default value is min(3% of free memory, 128MB) 3664c9b1d098SAndrew Shewmaker * 128MB is enough to recover with sshd/login, bash, and top/kill. 3665c9b1d098SAndrew Shewmaker */ 36661640879aSAndrew Shewmaker static int init_user_reserve(void) 3667c9b1d098SAndrew Shewmaker { 3668c9b1d098SAndrew Shewmaker unsigned long free_kbytes; 3669c9b1d098SAndrew Shewmaker 3670c41f012aSMichal Hocko free_kbytes = global_zone_page_state(NR_FREE_PAGES) << (PAGE_SHIFT - 10); 3671c9b1d098SAndrew Shewmaker 3672c9b1d098SAndrew Shewmaker sysctl_user_reserve_kbytes = min(free_kbytes / 32, 1UL << 17); 3673c9b1d098SAndrew Shewmaker return 0; 3674c9b1d098SAndrew Shewmaker } 3675a64fb3cdSPaul Gortmaker subsys_initcall(init_user_reserve); 36764eeab4f5SAndrew Shewmaker 36774eeab4f5SAndrew Shewmaker /* 36784eeab4f5SAndrew Shewmaker * Initialise sysctl_admin_reserve_kbytes. 36794eeab4f5SAndrew Shewmaker * 36804eeab4f5SAndrew Shewmaker * The purpose of sysctl_admin_reserve_kbytes is to allow the sys admin 36814eeab4f5SAndrew Shewmaker * to log in and kill a memory hogging process. 36824eeab4f5SAndrew Shewmaker * 36834eeab4f5SAndrew Shewmaker * Systems with more than 256MB will reserve 8MB, enough to recover 36844eeab4f5SAndrew Shewmaker * with sshd, bash, and top in OVERCOMMIT_GUESS. Smaller systems will 36854eeab4f5SAndrew Shewmaker * only reserve 3% of free pages by default. 36864eeab4f5SAndrew Shewmaker */ 36871640879aSAndrew Shewmaker static int init_admin_reserve(void) 36884eeab4f5SAndrew Shewmaker { 36894eeab4f5SAndrew Shewmaker unsigned long free_kbytes; 36904eeab4f5SAndrew Shewmaker 3691c41f012aSMichal Hocko free_kbytes = global_zone_page_state(NR_FREE_PAGES) << (PAGE_SHIFT - 10); 36924eeab4f5SAndrew Shewmaker 36934eeab4f5SAndrew Shewmaker sysctl_admin_reserve_kbytes = min(free_kbytes / 32, 1UL << 13); 36944eeab4f5SAndrew Shewmaker return 0; 36954eeab4f5SAndrew Shewmaker } 3696a64fb3cdSPaul Gortmaker subsys_initcall(init_admin_reserve); 36971640879aSAndrew Shewmaker 36981640879aSAndrew Shewmaker /* 36991640879aSAndrew Shewmaker * Reinititalise user and admin reserves if memory is added or removed. 37001640879aSAndrew Shewmaker * 37011640879aSAndrew Shewmaker * The default user reserve max is 128MB, and the default max for the 37021640879aSAndrew Shewmaker * admin reserve is 8MB. These are usually, but not always, enough to 37031640879aSAndrew Shewmaker * enable recovery from a memory hogging process using login/sshd, a shell, 37041640879aSAndrew Shewmaker * and tools like top. It may make sense to increase or even disable the 37051640879aSAndrew Shewmaker * reserve depending on the existence of swap or variations in the recovery 37061640879aSAndrew Shewmaker * tools. So, the admin may have changed them. 37071640879aSAndrew Shewmaker * 37081640879aSAndrew Shewmaker * If memory is added and the reserves have been eliminated or increased above 37091640879aSAndrew Shewmaker * the default max, then we'll trust the admin. 37101640879aSAndrew Shewmaker * 37111640879aSAndrew Shewmaker * If memory is removed and there isn't enough free memory, then we 37121640879aSAndrew Shewmaker * need to reset the reserves. 37131640879aSAndrew Shewmaker * 37141640879aSAndrew Shewmaker * Otherwise keep the reserve set by the admin. 37151640879aSAndrew Shewmaker */ 37161640879aSAndrew Shewmaker static int reserve_mem_notifier(struct notifier_block *nb, 37171640879aSAndrew Shewmaker unsigned long action, void *data) 37181640879aSAndrew Shewmaker { 37191640879aSAndrew Shewmaker unsigned long tmp, free_kbytes; 37201640879aSAndrew Shewmaker 37211640879aSAndrew Shewmaker switch (action) { 37221640879aSAndrew Shewmaker case MEM_ONLINE: 37231640879aSAndrew Shewmaker /* Default max is 128MB. Leave alone if modified by operator. */ 37241640879aSAndrew Shewmaker tmp = sysctl_user_reserve_kbytes; 37251640879aSAndrew Shewmaker if (0 < tmp && tmp < (1UL << 17)) 37261640879aSAndrew Shewmaker init_user_reserve(); 37271640879aSAndrew Shewmaker 37281640879aSAndrew Shewmaker /* Default max is 8MB. Leave alone if modified by operator. */ 37291640879aSAndrew Shewmaker tmp = sysctl_admin_reserve_kbytes; 37301640879aSAndrew Shewmaker if (0 < tmp && tmp < (1UL << 13)) 37311640879aSAndrew Shewmaker init_admin_reserve(); 37321640879aSAndrew Shewmaker 37331640879aSAndrew Shewmaker break; 37341640879aSAndrew Shewmaker case MEM_OFFLINE: 3735c41f012aSMichal Hocko free_kbytes = global_zone_page_state(NR_FREE_PAGES) << (PAGE_SHIFT - 10); 37361640879aSAndrew Shewmaker 37371640879aSAndrew Shewmaker if (sysctl_user_reserve_kbytes > free_kbytes) { 37381640879aSAndrew Shewmaker init_user_reserve(); 37391640879aSAndrew Shewmaker pr_info("vm.user_reserve_kbytes reset to %lu\n", 37401640879aSAndrew Shewmaker sysctl_user_reserve_kbytes); 37411640879aSAndrew Shewmaker } 37421640879aSAndrew Shewmaker 37431640879aSAndrew Shewmaker if (sysctl_admin_reserve_kbytes > free_kbytes) { 37441640879aSAndrew Shewmaker init_admin_reserve(); 37451640879aSAndrew Shewmaker pr_info("vm.admin_reserve_kbytes reset to %lu\n", 37461640879aSAndrew Shewmaker sysctl_admin_reserve_kbytes); 37471640879aSAndrew Shewmaker } 37481640879aSAndrew Shewmaker break; 37491640879aSAndrew Shewmaker default: 37501640879aSAndrew Shewmaker break; 37511640879aSAndrew Shewmaker } 37521640879aSAndrew Shewmaker return NOTIFY_OK; 37531640879aSAndrew Shewmaker } 37541640879aSAndrew Shewmaker 37551640879aSAndrew Shewmaker static int __meminit init_reserve_notifier(void) 37561640879aSAndrew Shewmaker { 37571eeaa4fdSLiu Shixin if (hotplug_memory_notifier(reserve_mem_notifier, DEFAULT_CALLBACK_PRI)) 3758b1de0d13SMitchel Humpherys pr_err("Failed registering memory add/remove notifier for admin reserve\n"); 37591640879aSAndrew Shewmaker 37601640879aSAndrew Shewmaker return 0; 37611640879aSAndrew Shewmaker } 3762a64fb3cdSPaul Gortmaker subsys_initcall(init_reserve_notifier); 3763