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 1472e7ce7d3SLiam R. Howlett /* 1482e7ce7d3SLiam R. Howlett * check_brk_limits() - Use platform specific check of range & verify mlock 1492e7ce7d3SLiam R. Howlett * limits. 1502e7ce7d3SLiam R. Howlett * @addr: The address to check 1512e7ce7d3SLiam R. Howlett * @len: The size of increase. 1522e7ce7d3SLiam R. Howlett * 1532e7ce7d3SLiam R. Howlett * Return: 0 on success. 1542e7ce7d3SLiam R. Howlett */ 1552e7ce7d3SLiam R. Howlett static int check_brk_limits(unsigned long addr, unsigned long len) 1562e7ce7d3SLiam R. Howlett { 1572e7ce7d3SLiam R. Howlett unsigned long mapped_addr; 1582e7ce7d3SLiam R. Howlett 1592e7ce7d3SLiam R. Howlett mapped_addr = get_unmapped_area(NULL, addr, len, 0, MAP_FIXED); 1602e7ce7d3SLiam R. Howlett if (IS_ERR_VALUE(mapped_addr)) 1612e7ce7d3SLiam R. Howlett return mapped_addr; 1622e7ce7d3SLiam R. Howlett 1632e7ce7d3SLiam R. Howlett return mlock_future_check(current->mm, current->mm->def_flags, len); 1642e7ce7d3SLiam R. Howlett } 1652e7ce7d3SLiam R. Howlett static int do_brk_munmap(struct ma_state *mas, struct vm_area_struct *vma, 1662e7ce7d3SLiam R. Howlett unsigned long newbrk, unsigned long oldbrk, 167bb177a73SMichal Hocko struct list_head *uf); 1682e7ce7d3SLiam R. Howlett static int do_brk_flags(struct ma_state *mas, struct vm_area_struct *brkvma, 169763ecb03SLiam R. Howlett unsigned long addr, unsigned long request, unsigned long flags); 1706a6160a7SHeiko Carstens SYSCALL_DEFINE1(brk, unsigned long, brk) 1711da177e4SLinus Torvalds { 1729bc8039eSYang Shi unsigned long newbrk, oldbrk, origbrk; 1731da177e4SLinus Torvalds struct mm_struct *mm = current->mm; 1742e7ce7d3SLiam R. Howlett struct vm_area_struct *brkvma, *next = NULL; 175a5b4592cSJiri Kosina unsigned long min_brk; 176128557ffSMichel Lespinasse bool populate; 1779bc8039eSYang Shi bool downgraded = false; 178897ab3e0SMike Rapoport LIST_HEAD(uf); 1792e7ce7d3SLiam R. Howlett MA_STATE(mas, &mm->mm_mt, 0, 0); 1801da177e4SLinus Torvalds 181d8ed45c5SMichel Lespinasse if (mmap_write_lock_killable(mm)) 182dc0ef0dfSMichal Hocko return -EINTR; 1831da177e4SLinus Torvalds 1849bc8039eSYang Shi origbrk = mm->brk; 1859bc8039eSYang Shi 186a5b4592cSJiri Kosina #ifdef CONFIG_COMPAT_BRK 1875520e894SJiri Kosina /* 1885520e894SJiri Kosina * CONFIG_COMPAT_BRK can still be overridden by setting 1895520e894SJiri Kosina * randomize_va_space to 2, which will still cause mm->start_brk 1905520e894SJiri Kosina * to be arbitrarily shifted 1915520e894SJiri Kosina */ 1924471a675SJiri Kosina if (current->brk_randomized) 1935520e894SJiri Kosina min_brk = mm->start_brk; 1945520e894SJiri Kosina else 1955520e894SJiri Kosina min_brk = mm->end_data; 196a5b4592cSJiri Kosina #else 197a5b4592cSJiri Kosina min_brk = mm->start_brk; 198a5b4592cSJiri Kosina #endif 199a5b4592cSJiri Kosina if (brk < min_brk) 2001da177e4SLinus Torvalds goto out; 2011e624196SRam Gupta 2021e624196SRam Gupta /* 2031e624196SRam Gupta * Check against rlimit here. If this check is done later after the test 2041e624196SRam Gupta * of oldbrk with newbrk then it can escape the test and let the data 2051e624196SRam Gupta * segment grow beyond its set limit the in case where the limit is 2061e624196SRam Gupta * not page aligned -Ram Gupta 2071e624196SRam Gupta */ 2088764b338SCyrill Gorcunov if (check_data_rlimit(rlimit(RLIMIT_DATA), brk, mm->start_brk, 2098764b338SCyrill Gorcunov mm->end_data, mm->start_data)) 2101e624196SRam Gupta goto out; 2111e624196SRam Gupta 2121da177e4SLinus Torvalds newbrk = PAGE_ALIGN(brk); 2131da177e4SLinus Torvalds oldbrk = PAGE_ALIGN(mm->brk); 2149bc8039eSYang Shi if (oldbrk == newbrk) { 2159bc8039eSYang Shi mm->brk = brk; 2169bc8039eSYang Shi goto success; 2179bc8039eSYang Shi } 2181da177e4SLinus Torvalds 2199bc8039eSYang Shi /* 2209bc8039eSYang Shi * Always allow shrinking brk. 2212e7ce7d3SLiam R. Howlett * do_brk_munmap() may downgrade mmap_lock to read. 2229bc8039eSYang Shi */ 2231da177e4SLinus Torvalds if (brk <= mm->brk) { 2249bc8039eSYang Shi int ret; 2259bc8039eSYang Shi 2262e7ce7d3SLiam R. Howlett /* Search one past newbrk */ 2272e7ce7d3SLiam R. Howlett mas_set(&mas, newbrk); 2282e7ce7d3SLiam R. Howlett brkvma = mas_find(&mas, oldbrk); 2292e7ce7d3SLiam R. Howlett BUG_ON(brkvma == NULL); 2302e7ce7d3SLiam R. Howlett if (brkvma->vm_start >= oldbrk) 2312e7ce7d3SLiam R. Howlett goto out; /* mapping intersects with an existing non-brk vma. */ 2329bc8039eSYang Shi /* 2332e7ce7d3SLiam R. Howlett * mm->brk must be protected by write mmap_lock. 2342e7ce7d3SLiam R. Howlett * do_brk_munmap() may downgrade the lock, so update it 2352e7ce7d3SLiam R. Howlett * before calling do_brk_munmap(). 2369bc8039eSYang Shi */ 2379bc8039eSYang Shi mm->brk = brk; 2382e7ce7d3SLiam R. Howlett ret = do_brk_munmap(&mas, brkvma, newbrk, oldbrk, &uf); 2392e7ce7d3SLiam R. Howlett if (ret == 1) { 2402e7ce7d3SLiam R. Howlett downgraded = true; 2412e7ce7d3SLiam R. Howlett goto success; 2422e7ce7d3SLiam R. Howlett } else if (!ret) 2432e7ce7d3SLiam R. Howlett goto success; 2442e7ce7d3SLiam R. Howlett 2459bc8039eSYang Shi mm->brk = origbrk; 2461da177e4SLinus Torvalds goto out; 2471da177e4SLinus Torvalds } 2481da177e4SLinus Torvalds 2492e7ce7d3SLiam R. Howlett if (check_brk_limits(oldbrk, newbrk - oldbrk)) 2502e7ce7d3SLiam R. Howlett goto out; 2512e7ce7d3SLiam R. Howlett 2522e7ce7d3SLiam R. Howlett /* 2532e7ce7d3SLiam R. Howlett * Only check if the next VMA is within the stack_guard_gap of the 2542e7ce7d3SLiam R. Howlett * expansion area 2552e7ce7d3SLiam R. Howlett */ 2562e7ce7d3SLiam R. Howlett mas_set(&mas, oldbrk); 2572e7ce7d3SLiam R. Howlett next = mas_find(&mas, newbrk - 1 + PAGE_SIZE + stack_guard_gap); 2581be7107fSHugh Dickins if (next && newbrk + PAGE_SIZE > vm_start_gap(next)) 2591da177e4SLinus Torvalds goto out; 2601da177e4SLinus Torvalds 2612e7ce7d3SLiam R. Howlett brkvma = mas_prev(&mas, mm->start_brk); 2621da177e4SLinus Torvalds /* Ok, looks good - let it rip. */ 2632e7ce7d3SLiam R. Howlett if (do_brk_flags(&mas, brkvma, oldbrk, newbrk - oldbrk, 0) < 0) 2641da177e4SLinus Torvalds goto out; 2652e7ce7d3SLiam R. Howlett 2661da177e4SLinus Torvalds mm->brk = brk; 2679bc8039eSYang Shi 2689bc8039eSYang Shi success: 269128557ffSMichel Lespinasse populate = newbrk > oldbrk && (mm->def_flags & VM_LOCKED) != 0; 2709bc8039eSYang Shi if (downgraded) 271d8ed45c5SMichel Lespinasse mmap_read_unlock(mm); 2729bc8039eSYang Shi else 273d8ed45c5SMichel Lespinasse mmap_write_unlock(mm); 274897ab3e0SMike Rapoport userfaultfd_unmap_complete(mm, &uf); 275128557ffSMichel Lespinasse if (populate) 276128557ffSMichel Lespinasse mm_populate(oldbrk, newbrk - oldbrk); 277128557ffSMichel Lespinasse return brk; 278128557ffSMichel Lespinasse 2791da177e4SLinus Torvalds out: 280d8ed45c5SMichel Lespinasse mmap_write_unlock(mm); 281b7204006SAdrian Huang return origbrk; 2821da177e4SLinus Torvalds } 2831da177e4SLinus Torvalds 284d4af56c5SLiam R. Howlett #if defined(CONFIG_DEBUG_VM_MAPLE_TREE) 285d4af56c5SLiam R. Howlett extern void mt_validate(struct maple_tree *mt); 286d4af56c5SLiam R. Howlett extern void mt_dump(const struct maple_tree *mt); 2871da177e4SLinus Torvalds 288d4af56c5SLiam R. Howlett /* Validate the maple tree */ 289d4af56c5SLiam R. Howlett static void validate_mm_mt(struct mm_struct *mm) 290d4af56c5SLiam R. Howlett { 291d4af56c5SLiam R. Howlett struct maple_tree *mt = &mm->mm_mt; 292763ecb03SLiam R. Howlett struct vm_area_struct *vma_mt; 293d4af56c5SLiam R. Howlett 294d4af56c5SLiam R. Howlett MA_STATE(mas, mt, 0, 0); 295d4af56c5SLiam R. Howlett 296d4af56c5SLiam R. Howlett mt_validate(&mm->mm_mt); 297d4af56c5SLiam R. Howlett mas_for_each(&mas, vma_mt, ULONG_MAX) { 298763ecb03SLiam R. Howlett if ((vma_mt->vm_start != mas.index) || 299763ecb03SLiam R. Howlett (vma_mt->vm_end - 1 != mas.last)) { 300d4af56c5SLiam R. Howlett pr_emerg("issue in %s\n", current->comm); 301d4af56c5SLiam R. Howlett dump_stack(); 302d4af56c5SLiam R. Howlett dump_vma(vma_mt); 303d4af56c5SLiam R. Howlett pr_emerg("mt piv: %p %lu - %lu\n", vma_mt, 304d4af56c5SLiam R. Howlett mas.index, mas.last); 305d4af56c5SLiam R. Howlett pr_emerg("mt vma: %p %lu - %lu\n", vma_mt, 306d4af56c5SLiam R. Howlett vma_mt->vm_start, vma_mt->vm_end); 307d4af56c5SLiam R. Howlett 308d4af56c5SLiam R. Howlett mt_dump(mas.tree); 309d4af56c5SLiam R. Howlett if (vma_mt->vm_end != mas.last + 1) { 310d4af56c5SLiam R. Howlett pr_err("vma: %p vma_mt %lu-%lu\tmt %lu-%lu\n", 311d4af56c5SLiam R. Howlett mm, vma_mt->vm_start, vma_mt->vm_end, 312d4af56c5SLiam R. Howlett mas.index, mas.last); 313d4af56c5SLiam R. Howlett mt_dump(mas.tree); 314d4af56c5SLiam R. Howlett } 315d4af56c5SLiam R. Howlett VM_BUG_ON_MM(vma_mt->vm_end != mas.last + 1, mm); 316d4af56c5SLiam R. Howlett if (vma_mt->vm_start != mas.index) { 317d4af56c5SLiam R. Howlett pr_err("vma: %p vma_mt %p %lu - %lu doesn't match\n", 318d4af56c5SLiam R. Howlett mm, vma_mt, vma_mt->vm_start, vma_mt->vm_end); 319d4af56c5SLiam R. Howlett mt_dump(mas.tree); 320d4af56c5SLiam R. Howlett } 321d4af56c5SLiam R. Howlett VM_BUG_ON_MM(vma_mt->vm_start != mas.index, mm); 322d4af56c5SLiam R. Howlett } 323d4af56c5SLiam R. Howlett } 324d4af56c5SLiam R. Howlett } 3251da177e4SLinus Torvalds 326eafd4dc4SRashika Kheria static void validate_mm(struct mm_struct *mm) 3271da177e4SLinus Torvalds { 3281da177e4SLinus Torvalds int bug = 0; 3291da177e4SLinus Torvalds int i = 0; 330763ecb03SLiam R. Howlett struct vm_area_struct *vma; 331763ecb03SLiam R. Howlett MA_STATE(mas, &mm->mm_mt, 0, 0); 332ff26f70fSAndrew Morton 333524e00b3SLiam R. Howlett validate_mm_mt(mm); 334524e00b3SLiam R. Howlett 335763ecb03SLiam R. Howlett mas_for_each(&mas, vma, ULONG_MAX) { 336524e00b3SLiam R. Howlett #ifdef CONFIG_DEBUG_VM_RB 33712352d3cSKonstantin Khlebnikov struct anon_vma *anon_vma = vma->anon_vma; 338ed8ea815SMichel Lespinasse struct anon_vma_chain *avc; 339ff26f70fSAndrew Morton 34012352d3cSKonstantin Khlebnikov if (anon_vma) { 34112352d3cSKonstantin Khlebnikov anon_vma_lock_read(anon_vma); 342ed8ea815SMichel Lespinasse list_for_each_entry(avc, &vma->anon_vma_chain, same_vma) 343ed8ea815SMichel Lespinasse anon_vma_interval_tree_verify(avc); 34412352d3cSKonstantin Khlebnikov anon_vma_unlock_read(anon_vma); 34512352d3cSKonstantin Khlebnikov } 346524e00b3SLiam R. Howlett #endif 3471da177e4SLinus Torvalds i++; 3481da177e4SLinus Torvalds } 3495a0768f6SMichel Lespinasse if (i != mm->map_count) { 350763ecb03SLiam R. Howlett pr_emerg("map_count %d mas_for_each %d\n", mm->map_count, i); 3515a0768f6SMichel Lespinasse bug = 1; 3525a0768f6SMichel Lespinasse } 35396dad67fSSasha Levin VM_BUG_ON_MM(bug, mm); 3541da177e4SLinus Torvalds } 355524e00b3SLiam R. Howlett 356524e00b3SLiam R. Howlett #else /* !CONFIG_DEBUG_VM_MAPLE_TREE */ 357d4af56c5SLiam R. Howlett #define validate_mm_mt(root) do { } while (0) 3581da177e4SLinus Torvalds #define validate_mm(mm) do { } while (0) 359524e00b3SLiam R. Howlett #endif /* CONFIG_DEBUG_VM_MAPLE_TREE */ 360d3737187SMichel Lespinasse 361bf181b9fSMichel Lespinasse /* 362bf181b9fSMichel Lespinasse * vma has some anon_vma assigned, and is already inserted on that 363bf181b9fSMichel Lespinasse * anon_vma's interval trees. 364bf181b9fSMichel Lespinasse * 365bf181b9fSMichel Lespinasse * Before updating the vma's vm_start / vm_end / vm_pgoff fields, the 366bf181b9fSMichel Lespinasse * vma must be removed from the anon_vma's interval trees using 367bf181b9fSMichel Lespinasse * anon_vma_interval_tree_pre_update_vma(). 368bf181b9fSMichel Lespinasse * 369bf181b9fSMichel Lespinasse * After the update, the vma will be reinserted using 370bf181b9fSMichel Lespinasse * anon_vma_interval_tree_post_update_vma(). 371bf181b9fSMichel Lespinasse * 372c1e8d7c6SMichel Lespinasse * The entire update must be protected by exclusive mmap_lock and by 373bf181b9fSMichel Lespinasse * the root anon_vma's mutex. 374bf181b9fSMichel Lespinasse */ 375bf181b9fSMichel Lespinasse static inline void 376bf181b9fSMichel Lespinasse anon_vma_interval_tree_pre_update_vma(struct vm_area_struct *vma) 377bf181b9fSMichel Lespinasse { 378bf181b9fSMichel Lespinasse struct anon_vma_chain *avc; 379bf181b9fSMichel Lespinasse 380bf181b9fSMichel Lespinasse list_for_each_entry(avc, &vma->anon_vma_chain, same_vma) 381bf181b9fSMichel Lespinasse anon_vma_interval_tree_remove(avc, &avc->anon_vma->rb_root); 382bf181b9fSMichel Lespinasse } 383bf181b9fSMichel Lespinasse 384bf181b9fSMichel Lespinasse static inline void 385bf181b9fSMichel Lespinasse anon_vma_interval_tree_post_update_vma(struct vm_area_struct *vma) 386bf181b9fSMichel Lespinasse { 387bf181b9fSMichel Lespinasse struct anon_vma_chain *avc; 388bf181b9fSMichel Lespinasse 389bf181b9fSMichel Lespinasse list_for_each_entry(avc, &vma->anon_vma_chain, same_vma) 390bf181b9fSMichel Lespinasse anon_vma_interval_tree_insert(avc, &avc->anon_vma->rb_root); 391bf181b9fSMichel Lespinasse } 392bf181b9fSMichel Lespinasse 393e8420a8eSCyril Hrubis static unsigned long count_vma_pages_range(struct mm_struct *mm, 394e8420a8eSCyril Hrubis unsigned long addr, unsigned long end) 395e8420a8eSCyril Hrubis { 3962e3af1dbSMatthew Wilcox (Oracle) VMA_ITERATOR(vmi, mm, addr); 397e8420a8eSCyril Hrubis struct vm_area_struct *vma; 3982e3af1dbSMatthew Wilcox (Oracle) unsigned long nr_pages = 0; 399e8420a8eSCyril Hrubis 4002e3af1dbSMatthew Wilcox (Oracle) for_each_vma_range(vmi, vma, end) { 4012e3af1dbSMatthew Wilcox (Oracle) unsigned long vm_start = max(addr, vma->vm_start); 4022e3af1dbSMatthew Wilcox (Oracle) unsigned long vm_end = min(end, vma->vm_end); 403e8420a8eSCyril Hrubis 4042e3af1dbSMatthew Wilcox (Oracle) nr_pages += PHYS_PFN(vm_end - vm_start); 405e8420a8eSCyril Hrubis } 406e8420a8eSCyril Hrubis 407e8420a8eSCyril Hrubis return nr_pages; 408e8420a8eSCyril Hrubis } 409e8420a8eSCyril Hrubis 410*c154124fSLiam R. Howlett static void __vma_link_file(struct vm_area_struct *vma, 411*c154124fSLiam R. Howlett struct address_space *mapping) 4121da177e4SLinus Torvalds { 4131da177e4SLinus Torvalds if (vma->vm_flags & VM_SHARED) 414cf508b58SMiaohe Lin mapping_allow_writable(mapping); 4151da177e4SLinus Torvalds 4161da177e4SLinus Torvalds flush_dcache_mmap_lock(mapping); 4176b2dbba8SMichel Lespinasse vma_interval_tree_insert(vma, &mapping->i_mmap); 4181da177e4SLinus Torvalds flush_dcache_mmap_unlock(mapping); 4191da177e4SLinus Torvalds } 4201da177e4SLinus Torvalds 421d4af56c5SLiam R. Howlett /* 422d4af56c5SLiam R. Howlett * vma_mas_store() - Store a VMA in the maple tree. 423d4af56c5SLiam R. Howlett * @vma: The vm_area_struct 424d4af56c5SLiam R. Howlett * @mas: The maple state 425d4af56c5SLiam R. Howlett * 426d4af56c5SLiam R. Howlett * Efficient way to store a VMA in the maple tree when the @mas has already 427d4af56c5SLiam R. Howlett * walked to the correct location. 428d4af56c5SLiam R. Howlett * 429d4af56c5SLiam R. Howlett * Note: the end address is inclusive in the maple tree. 430d4af56c5SLiam R. Howlett */ 431d4af56c5SLiam R. Howlett void vma_mas_store(struct vm_area_struct *vma, struct ma_state *mas) 432d4af56c5SLiam R. Howlett { 433d4af56c5SLiam R. Howlett trace_vma_store(mas->tree, vma); 434d4af56c5SLiam R. Howlett mas_set_range(mas, vma->vm_start, vma->vm_end - 1); 435d4af56c5SLiam R. Howlett mas_store_prealloc(mas, vma); 436d4af56c5SLiam R. Howlett } 437d4af56c5SLiam R. Howlett 438d4af56c5SLiam R. Howlett /* 439d4af56c5SLiam R. Howlett * vma_mas_remove() - Remove a VMA from the maple tree. 440d4af56c5SLiam R. Howlett * @vma: The vm_area_struct 441d4af56c5SLiam R. Howlett * @mas: The maple state 442d4af56c5SLiam R. Howlett * 443d4af56c5SLiam R. Howlett * Efficient way to remove a VMA from the maple tree when the @mas has already 444d4af56c5SLiam R. Howlett * been established and points to the correct location. 445d4af56c5SLiam R. Howlett * Note: the end address is inclusive in the maple tree. 446d4af56c5SLiam R. Howlett */ 447d4af56c5SLiam R. Howlett void vma_mas_remove(struct vm_area_struct *vma, struct ma_state *mas) 448d4af56c5SLiam R. Howlett { 449d4af56c5SLiam R. Howlett trace_vma_mas_szero(mas->tree, vma->vm_start, vma->vm_end - 1); 450d4af56c5SLiam R. Howlett mas->index = vma->vm_start; 451d4af56c5SLiam R. Howlett mas->last = vma->vm_end - 1; 452d4af56c5SLiam R. Howlett mas_store_prealloc(mas, NULL); 453d4af56c5SLiam R. Howlett } 454d4af56c5SLiam R. Howlett 455d4af56c5SLiam R. Howlett /* 456d4af56c5SLiam R. Howlett * vma_mas_szero() - Set a given range to zero. Used when modifying a 457d4af56c5SLiam R. Howlett * vm_area_struct start or end. 458d4af56c5SLiam R. Howlett * 459d4af56c5SLiam R. Howlett * @mm: The struct_mm 460d4af56c5SLiam R. Howlett * @start: The start address to zero 461d4af56c5SLiam R. Howlett * @end: The end address to zero. 462d4af56c5SLiam R. Howlett */ 463d4af56c5SLiam R. Howlett static inline void vma_mas_szero(struct ma_state *mas, unsigned long start, 464d4af56c5SLiam R. Howlett unsigned long end) 465d4af56c5SLiam R. Howlett { 466d4af56c5SLiam R. Howlett trace_vma_mas_szero(mas->tree, start, end - 1); 467d4af56c5SLiam R. Howlett mas_set_range(mas, start, end - 1); 468d4af56c5SLiam R. Howlett mas_store_prealloc(mas, NULL); 469d4af56c5SLiam R. Howlett } 470d4af56c5SLiam R. Howlett 471763ecb03SLiam R. Howlett static int vma_link(struct mm_struct *mm, struct vm_area_struct *vma) 4721da177e4SLinus Torvalds { 473d4af56c5SLiam R. Howlett MA_STATE(mas, &mm->mm_mt, 0, 0); 4741da177e4SLinus Torvalds struct address_space *mapping = NULL; 4751da177e4SLinus Torvalds 476d4af56c5SLiam R. Howlett if (mas_preallocate(&mas, vma, GFP_KERNEL)) 477d4af56c5SLiam R. Howlett return -ENOMEM; 478d4af56c5SLiam R. Howlett 47964ac4940SHuang Shijie if (vma->vm_file) { 4801da177e4SLinus Torvalds mapping = vma->vm_file->f_mapping; 48183cde9e8SDavidlohr Bueso i_mmap_lock_write(mapping); 48264ac4940SHuang Shijie } 4831da177e4SLinus Torvalds 484d4af56c5SLiam R. Howlett vma_mas_store(vma, &mas); 4851da177e4SLinus Torvalds 486*c154124fSLiam R. Howlett if (mapping) { 487*c154124fSLiam R. Howlett __vma_link_file(vma, mapping); 48883cde9e8SDavidlohr Bueso i_mmap_unlock_write(mapping); 489*c154124fSLiam R. Howlett } 4901da177e4SLinus Torvalds 4911da177e4SLinus Torvalds mm->map_count++; 4921da177e4SLinus Torvalds validate_mm(mm); 493d4af56c5SLiam R. Howlett return 0; 4941da177e4SLinus Torvalds } 4951da177e4SLinus Torvalds 4961da177e4SLinus Torvalds /* 4974dd1b841SLiam R. Howlett * vma_expand - Expand an existing VMA 4984dd1b841SLiam R. Howlett * 4994dd1b841SLiam R. Howlett * @mas: The maple state 5004dd1b841SLiam R. Howlett * @vma: The vma to expand 5014dd1b841SLiam R. Howlett * @start: The start of the vma 5024dd1b841SLiam R. Howlett * @end: The exclusive end of the vma 5034dd1b841SLiam R. Howlett * @pgoff: The page offset of vma 5044dd1b841SLiam R. Howlett * @next: The current of next vma. 5054dd1b841SLiam R. Howlett * 5064dd1b841SLiam R. Howlett * Expand @vma to @start and @end. Can expand off the start and end. Will 5074dd1b841SLiam R. Howlett * expand over @next if it's different from @vma and @end == @next->vm_end. 5084dd1b841SLiam R. Howlett * Checking if the @vma can expand and merge with @next needs to be handled by 5094dd1b841SLiam R. Howlett * the caller. 5104dd1b841SLiam R. Howlett * 5114dd1b841SLiam R. Howlett * Returns: 0 on success 5124dd1b841SLiam R. Howlett */ 5134dd1b841SLiam R. Howlett inline int vma_expand(struct ma_state *mas, struct vm_area_struct *vma, 5144dd1b841SLiam R. Howlett unsigned long start, unsigned long end, pgoff_t pgoff, 5154dd1b841SLiam R. Howlett struct vm_area_struct *next) 5164dd1b841SLiam R. Howlett { 5174dd1b841SLiam R. Howlett struct mm_struct *mm = vma->vm_mm; 5184dd1b841SLiam R. Howlett struct address_space *mapping = NULL; 5194dd1b841SLiam R. Howlett struct rb_root_cached *root = NULL; 5204dd1b841SLiam R. Howlett struct anon_vma *anon_vma = vma->anon_vma; 5214dd1b841SLiam R. Howlett struct file *file = vma->vm_file; 5224dd1b841SLiam R. Howlett bool remove_next = false; 5234dd1b841SLiam R. Howlett 5244dd1b841SLiam R. Howlett if (next && (vma != next) && (end == next->vm_end)) { 5254dd1b841SLiam R. Howlett remove_next = true; 5264dd1b841SLiam R. Howlett if (next->anon_vma && !vma->anon_vma) { 5274dd1b841SLiam R. Howlett int error; 5284dd1b841SLiam R. Howlett 5294dd1b841SLiam R. Howlett anon_vma = next->anon_vma; 5304dd1b841SLiam R. Howlett vma->anon_vma = anon_vma; 5314dd1b841SLiam R. Howlett error = anon_vma_clone(vma, next); 5324dd1b841SLiam R. Howlett if (error) 5334dd1b841SLiam R. Howlett return error; 5344dd1b841SLiam R. Howlett } 5354dd1b841SLiam R. Howlett } 5364dd1b841SLiam R. Howlett 5374dd1b841SLiam R. Howlett /* Not merging but overwriting any part of next is not handled. */ 5384dd1b841SLiam R. Howlett VM_BUG_ON(next && !remove_next && next != vma && end > next->vm_start); 5394dd1b841SLiam R. Howlett /* Only handles expanding */ 5404dd1b841SLiam R. Howlett VM_BUG_ON(vma->vm_start < start || vma->vm_end > end); 5414dd1b841SLiam R. Howlett 5424dd1b841SLiam R. Howlett if (mas_preallocate(mas, vma, GFP_KERNEL)) 5434dd1b841SLiam R. Howlett goto nomem; 5444dd1b841SLiam R. Howlett 5454dd1b841SLiam R. Howlett vma_adjust_trans_huge(vma, start, end, 0); 5464dd1b841SLiam R. Howlett 5474dd1b841SLiam R. Howlett if (file) { 5484dd1b841SLiam R. Howlett mapping = file->f_mapping; 5494dd1b841SLiam R. Howlett root = &mapping->i_mmap; 5504dd1b841SLiam R. Howlett uprobe_munmap(vma, vma->vm_start, vma->vm_end); 5514dd1b841SLiam R. Howlett i_mmap_lock_write(mapping); 5524dd1b841SLiam R. Howlett } 5534dd1b841SLiam R. Howlett 5544dd1b841SLiam R. Howlett if (anon_vma) { 5554dd1b841SLiam R. Howlett anon_vma_lock_write(anon_vma); 5564dd1b841SLiam R. Howlett anon_vma_interval_tree_pre_update_vma(vma); 5574dd1b841SLiam R. Howlett } 5584dd1b841SLiam R. Howlett 5594dd1b841SLiam R. Howlett if (file) { 5604dd1b841SLiam R. Howlett flush_dcache_mmap_lock(mapping); 5614dd1b841SLiam R. Howlett vma_interval_tree_remove(vma, root); 5624dd1b841SLiam R. Howlett } 5634dd1b841SLiam R. Howlett 5644dd1b841SLiam R. Howlett vma->vm_start = start; 5654dd1b841SLiam R. Howlett vma->vm_end = end; 5664dd1b841SLiam R. Howlett vma->vm_pgoff = pgoff; 5674dd1b841SLiam R. Howlett /* Note: mas must be pointing to the expanding VMA */ 5684dd1b841SLiam R. Howlett vma_mas_store(vma, mas); 5694dd1b841SLiam R. Howlett 5704dd1b841SLiam R. Howlett if (file) { 5714dd1b841SLiam R. Howlett vma_interval_tree_insert(vma, root); 5724dd1b841SLiam R. Howlett flush_dcache_mmap_unlock(mapping); 5734dd1b841SLiam R. Howlett } 5744dd1b841SLiam R. Howlett 5754dd1b841SLiam R. Howlett /* Expanding over the next vma */ 576763ecb03SLiam R. Howlett if (remove_next && file) { 5774dd1b841SLiam R. Howlett __remove_shared_vm_struct(next, file, mapping); 5784dd1b841SLiam R. Howlett } 5794dd1b841SLiam R. Howlett 5804dd1b841SLiam R. Howlett if (anon_vma) { 5814dd1b841SLiam R. Howlett anon_vma_interval_tree_post_update_vma(vma); 5824dd1b841SLiam R. Howlett anon_vma_unlock_write(anon_vma); 5834dd1b841SLiam R. Howlett } 5844dd1b841SLiam R. Howlett 5854dd1b841SLiam R. Howlett if (file) { 5864dd1b841SLiam R. Howlett i_mmap_unlock_write(mapping); 5874dd1b841SLiam R. Howlett uprobe_mmap(vma); 5884dd1b841SLiam R. Howlett } 5894dd1b841SLiam R. Howlett 5904dd1b841SLiam R. Howlett if (remove_next) { 5914dd1b841SLiam R. Howlett if (file) { 5924dd1b841SLiam R. Howlett uprobe_munmap(next, next->vm_start, next->vm_end); 5934dd1b841SLiam R. Howlett fput(file); 5944dd1b841SLiam R. Howlett } 5954dd1b841SLiam R. Howlett if (next->anon_vma) 5964dd1b841SLiam R. Howlett anon_vma_merge(vma, next); 5974dd1b841SLiam R. Howlett mm->map_count--; 5984dd1b841SLiam R. Howlett mpol_put(vma_policy(next)); 5994dd1b841SLiam R. Howlett vm_area_free(next); 6004dd1b841SLiam R. Howlett } 6014dd1b841SLiam R. Howlett 6024dd1b841SLiam R. Howlett validate_mm(mm); 6034dd1b841SLiam R. Howlett return 0; 6044dd1b841SLiam R. Howlett 6054dd1b841SLiam R. Howlett nomem: 6064dd1b841SLiam R. Howlett return -ENOMEM; 6074dd1b841SLiam R. Howlett } 6084dd1b841SLiam R. Howlett 6094dd1b841SLiam R. Howlett /* 6101da177e4SLinus Torvalds * We cannot adjust vm_start, vm_end, vm_pgoff fields of a vma that 6111da177e4SLinus Torvalds * is already present in an i_mmap tree without adjusting the tree. 6121da177e4SLinus Torvalds * The following helper function should be used when such adjustments 6131da177e4SLinus Torvalds * are necessary. The "insert" vma (if any) is to be inserted 6141da177e4SLinus Torvalds * before we drop the necessary locks. 6151da177e4SLinus Torvalds */ 616e86f15eeSAndrea Arcangeli int __vma_adjust(struct vm_area_struct *vma, unsigned long start, 617e86f15eeSAndrea Arcangeli unsigned long end, pgoff_t pgoff, struct vm_area_struct *insert, 618e86f15eeSAndrea Arcangeli struct vm_area_struct *expand) 6191da177e4SLinus Torvalds { 6201da177e4SLinus Torvalds struct mm_struct *mm = vma->vm_mm; 621524e00b3SLiam R. Howlett struct vm_area_struct *next_next, *next = find_vma(mm, vma->vm_end); 622524e00b3SLiam R. Howlett struct vm_area_struct *orig_vma = vma; 6231da177e4SLinus Torvalds struct address_space *mapping = NULL; 624f808c13fSDavidlohr Bueso struct rb_root_cached *root = NULL; 625012f1800SRik van Riel struct anon_vma *anon_vma = NULL; 6261da177e4SLinus Torvalds struct file *file = vma->vm_file; 627524e00b3SLiam R. Howlett bool vma_changed = false; 6281da177e4SLinus Torvalds long adjust_next = 0; 6291da177e4SLinus Torvalds int remove_next = 0; 630d4af56c5SLiam R. Howlett MA_STATE(mas, &mm->mm_mt, 0, 0); 631734537c9SKirill A. Shutemov struct vm_area_struct *exporter = NULL, *importer = NULL; 632287d97acSLinus Torvalds 633d4af56c5SLiam R. Howlett if (next && !insert) { 6341da177e4SLinus Torvalds if (end >= next->vm_end) { 6351da177e4SLinus Torvalds /* 6361da177e4SLinus Torvalds * vma expands, overlapping all the next, and 6371da177e4SLinus Torvalds * perhaps the one after too (mprotect case 6). 63886d12e47SAndrea Arcangeli * The only other cases that gets here are 639e86f15eeSAndrea Arcangeli * case 1, case 7 and case 8. 640e86f15eeSAndrea Arcangeli */ 641e86f15eeSAndrea Arcangeli if (next == expand) { 642e86f15eeSAndrea Arcangeli /* 643e86f15eeSAndrea Arcangeli * The only case where we don't expand "vma" 644e86f15eeSAndrea Arcangeli * and we expand "next" instead is case 8. 645e86f15eeSAndrea Arcangeli */ 646e86f15eeSAndrea Arcangeli VM_WARN_ON(end != next->vm_end); 647e86f15eeSAndrea Arcangeli /* 648e86f15eeSAndrea Arcangeli * remove_next == 3 means we're 649e86f15eeSAndrea Arcangeli * removing "vma" and that to do so we 650e86f15eeSAndrea Arcangeli * swapped "vma" and "next". 651e86f15eeSAndrea Arcangeli */ 652e86f15eeSAndrea Arcangeli remove_next = 3; 653e86f15eeSAndrea Arcangeli VM_WARN_ON(file != next->vm_file); 654e86f15eeSAndrea Arcangeli swap(vma, next); 655e86f15eeSAndrea Arcangeli } else { 656e86f15eeSAndrea Arcangeli VM_WARN_ON(expand != vma); 657e86f15eeSAndrea Arcangeli /* 658e86f15eeSAndrea Arcangeli * case 1, 6, 7, remove_next == 2 is case 6, 659e86f15eeSAndrea Arcangeli * remove_next == 1 is case 1 or 7. 6601da177e4SLinus Torvalds */ 661734537c9SKirill A. Shutemov remove_next = 1 + (end > next->vm_end); 662d4af56c5SLiam R. Howlett if (remove_next == 2) 663d4af56c5SLiam R. Howlett next_next = find_vma(mm, next->vm_end); 664d4af56c5SLiam R. Howlett 665e86f15eeSAndrea Arcangeli VM_WARN_ON(remove_next == 2 && 666763ecb03SLiam R. Howlett end != next_next->vm_end); 667e86f15eeSAndrea Arcangeli } 668e86f15eeSAndrea Arcangeli 669287d97acSLinus Torvalds exporter = next; 6701da177e4SLinus Torvalds importer = vma; 671734537c9SKirill A. Shutemov 672734537c9SKirill A. Shutemov /* 673734537c9SKirill A. Shutemov * If next doesn't have anon_vma, import from vma after 674734537c9SKirill A. Shutemov * next, if the vma overlaps with it. 675734537c9SKirill A. Shutemov */ 67697a42cd4SAndrea Arcangeli if (remove_next == 2 && !next->anon_vma) 677763ecb03SLiam R. Howlett exporter = next_next; 678734537c9SKirill A. Shutemov 6791da177e4SLinus Torvalds } else if (end > next->vm_start) { 6801da177e4SLinus Torvalds /* 6811da177e4SLinus Torvalds * vma expands, overlapping part of the next: 6821da177e4SLinus Torvalds * mprotect case 5 shifting the boundary up. 6831da177e4SLinus Torvalds */ 684f9d86a60SWei Yang adjust_next = (end - next->vm_start); 685287d97acSLinus Torvalds exporter = next; 6861da177e4SLinus Torvalds importer = vma; 687e86f15eeSAndrea Arcangeli VM_WARN_ON(expand != importer); 6881da177e4SLinus Torvalds } else if (end < vma->vm_end) { 6891da177e4SLinus Torvalds /* 6901da177e4SLinus Torvalds * vma shrinks, and !insert tells it's not 6911da177e4SLinus Torvalds * split_vma inserting another: so it must be 6921da177e4SLinus Torvalds * mprotect case 4 shifting the boundary down. 6931da177e4SLinus Torvalds */ 694f9d86a60SWei Yang adjust_next = -(vma->vm_end - end); 695287d97acSLinus Torvalds exporter = vma; 6961da177e4SLinus Torvalds importer = next; 697e86f15eeSAndrea Arcangeli VM_WARN_ON(expand != importer); 6981da177e4SLinus Torvalds } 6991da177e4SLinus Torvalds 7005beb4930SRik van Riel /* 7015beb4930SRik van Riel * Easily overlooked: when mprotect shifts the boundary, 7025beb4930SRik van Riel * make sure the expanding vma has anon_vma set if the 7035beb4930SRik van Riel * shrinking vma had, to cover any anon pages imported. 7045beb4930SRik van Riel */ 705287d97acSLinus Torvalds if (exporter && exporter->anon_vma && !importer->anon_vma) { 706c4ea95d7SDaniel Forrest int error; 707c4ea95d7SDaniel Forrest 708287d97acSLinus Torvalds importer->anon_vma = exporter->anon_vma; 709b800c91aSKonstantin Khlebnikov error = anon_vma_clone(importer, exporter); 7103fe89b3eSLeon Yu if (error) 711b800c91aSKonstantin Khlebnikov return error; 712b800c91aSKonstantin Khlebnikov } 7135beb4930SRik van Riel } 71437f9f559SKirill A. Shutemov 715d4af56c5SLiam R. Howlett if (mas_preallocate(&mas, vma, GFP_KERNEL)) 716d4af56c5SLiam R. Howlett return -ENOMEM; 717d4af56c5SLiam R. Howlett 718d4af56c5SLiam R. Howlett vma_adjust_trans_huge(orig_vma, start, end, adjust_next); 7191da177e4SLinus Torvalds if (file) { 7201da177e4SLinus Torvalds mapping = file->f_mapping; 7211da177e4SLinus Torvalds root = &mapping->i_mmap; 722cbc91f71SSrikar Dronamraju uprobe_munmap(vma, vma->vm_start, vma->vm_end); 723682968e0SSrikar Dronamraju 724682968e0SSrikar Dronamraju if (adjust_next) 72527ba0644SKirill A. Shutemov uprobe_munmap(next, next->vm_start, next->vm_end); 726682968e0SSrikar Dronamraju 72783cde9e8SDavidlohr Bueso i_mmap_lock_write(mapping); 728*c154124fSLiam R. Howlett if (insert && insert->vm_file) { 7291da177e4SLinus Torvalds /* 7306b2dbba8SMichel Lespinasse * Put into interval tree now, so instantiated pages 7311da177e4SLinus Torvalds * are visible to arm/parisc __flush_dcache_page 7321da177e4SLinus Torvalds * throughout; but we cannot insert into address 7331da177e4SLinus Torvalds * space until vma start or end is updated. 7341da177e4SLinus Torvalds */ 735*c154124fSLiam R. Howlett __vma_link_file(insert, insert->vm_file->f_mapping); 7361da177e4SLinus Torvalds } 7371da177e4SLinus Torvalds } 7381da177e4SLinus Torvalds 739012f1800SRik van Riel anon_vma = vma->anon_vma; 740bf181b9fSMichel Lespinasse if (!anon_vma && adjust_next) 741bf181b9fSMichel Lespinasse anon_vma = next->anon_vma; 742bf181b9fSMichel Lespinasse if (anon_vma) { 743e86f15eeSAndrea Arcangeli VM_WARN_ON(adjust_next && next->anon_vma && 744e86f15eeSAndrea Arcangeli anon_vma != next->anon_vma); 7454fc3f1d6SIngo Molnar anon_vma_lock_write(anon_vma); 746bf181b9fSMichel Lespinasse anon_vma_interval_tree_pre_update_vma(vma); 747bf181b9fSMichel Lespinasse if (adjust_next) 748bf181b9fSMichel Lespinasse anon_vma_interval_tree_pre_update_vma(next); 749bf181b9fSMichel Lespinasse } 750012f1800SRik van Riel 7510fc48a6eSWei Yang if (file) { 7521da177e4SLinus Torvalds flush_dcache_mmap_lock(mapping); 7536b2dbba8SMichel Lespinasse vma_interval_tree_remove(vma, root); 7541da177e4SLinus Torvalds if (adjust_next) 7556b2dbba8SMichel Lespinasse vma_interval_tree_remove(next, root); 7561da177e4SLinus Torvalds } 7571da177e4SLinus Torvalds 758d3737187SMichel Lespinasse if (start != vma->vm_start) { 7593b0e81a1SLiam R. Howlett if ((vma->vm_start < start) && 7603b0e81a1SLiam R. Howlett (!insert || (insert->vm_end != start))) { 761524e00b3SLiam R. Howlett vma_mas_szero(&mas, vma->vm_start, start); 7623b0e81a1SLiam R. Howlett VM_WARN_ON(insert && insert->vm_start > vma->vm_start); 7633b0e81a1SLiam R. Howlett } else { 764524e00b3SLiam R. Howlett vma_changed = true; 7653b0e81a1SLiam R. Howlett } 7661da177e4SLinus Torvalds vma->vm_start = start; 767d3737187SMichel Lespinasse } 768d3737187SMichel Lespinasse if (end != vma->vm_end) { 7693b0e81a1SLiam R. Howlett if (vma->vm_end > end) { 7703b0e81a1SLiam R. Howlett if (!insert || (insert->vm_start != end)) { 771524e00b3SLiam R. Howlett vma_mas_szero(&mas, end, vma->vm_end); 772763ecb03SLiam R. Howlett mas_reset(&mas); 7733b0e81a1SLiam R. Howlett VM_WARN_ON(insert && 7743b0e81a1SLiam R. Howlett insert->vm_end < vma->vm_end); 7753b0e81a1SLiam R. Howlett } 7763b0e81a1SLiam R. Howlett } else { 777524e00b3SLiam R. Howlett vma_changed = true; 7783b0e81a1SLiam R. Howlett } 7791da177e4SLinus Torvalds vma->vm_end = end; 780d3737187SMichel Lespinasse } 781d4af56c5SLiam R. Howlett 782524e00b3SLiam R. Howlett if (vma_changed) 783d4af56c5SLiam R. Howlett vma_mas_store(vma, &mas); 784d4af56c5SLiam R. Howlett 7851da177e4SLinus Torvalds vma->vm_pgoff = pgoff; 7861da177e4SLinus Torvalds if (adjust_next) { 787f9d86a60SWei Yang next->vm_start += adjust_next; 788f9d86a60SWei Yang next->vm_pgoff += adjust_next >> PAGE_SHIFT; 789d4af56c5SLiam R. Howlett vma_mas_store(next, &mas); 7901da177e4SLinus Torvalds } 7911da177e4SLinus Torvalds 7920fc48a6eSWei Yang if (file) { 7931da177e4SLinus Torvalds if (adjust_next) 7946b2dbba8SMichel Lespinasse vma_interval_tree_insert(next, root); 7956b2dbba8SMichel Lespinasse vma_interval_tree_insert(vma, root); 7961da177e4SLinus Torvalds flush_dcache_mmap_unlock(mapping); 7971da177e4SLinus Torvalds } 7981da177e4SLinus Torvalds 799763ecb03SLiam R. Howlett if (remove_next && file) { 8001da177e4SLinus Torvalds __remove_shared_vm_struct(next, file, mapping); 801d4af56c5SLiam R. Howlett if (remove_next == 2) 802d4af56c5SLiam R. Howlett __remove_shared_vm_struct(next_next, file, mapping); 8031da177e4SLinus Torvalds } else if (insert) { 8041da177e4SLinus Torvalds /* 8051da177e4SLinus Torvalds * split_vma has split insert from vma, and needs 8061da177e4SLinus Torvalds * us to insert it before dropping the locks 8071da177e4SLinus Torvalds * (it may either follow vma or precede it). 8081da177e4SLinus Torvalds */ 809763ecb03SLiam R. Howlett mas_reset(&mas); 810763ecb03SLiam R. Howlett vma_mas_store(insert, &mas); 811763ecb03SLiam R. Howlett mm->map_count++; 8121da177e4SLinus Torvalds } 8131da177e4SLinus Torvalds 814bf181b9fSMichel Lespinasse if (anon_vma) { 815bf181b9fSMichel Lespinasse anon_vma_interval_tree_post_update_vma(vma); 816bf181b9fSMichel Lespinasse if (adjust_next) 817bf181b9fSMichel Lespinasse anon_vma_interval_tree_post_update_vma(next); 81808b52706SKonstantin Khlebnikov anon_vma_unlock_write(anon_vma); 819bf181b9fSMichel Lespinasse } 8201da177e4SLinus Torvalds 8210fc48a6eSWei Yang if (file) { 822808fbdbeSWei Yang i_mmap_unlock_write(mapping); 8237b2d81d4SIngo Molnar uprobe_mmap(vma); 8242b144498SSrikar Dronamraju 8252b144498SSrikar Dronamraju if (adjust_next) 8267b2d81d4SIngo Molnar uprobe_mmap(next); 8272b144498SSrikar Dronamraju } 8282b144498SSrikar Dronamraju 8291da177e4SLinus Torvalds if (remove_next) { 830d4af56c5SLiam R. Howlett again: 831925d1c40SMatt Helsley if (file) { 832cbc91f71SSrikar Dronamraju uprobe_munmap(next, next->vm_start, next->vm_end); 8331da177e4SLinus Torvalds fput(file); 834925d1c40SMatt Helsley } 8355beb4930SRik van Riel if (next->anon_vma) 8365beb4930SRik van Riel anon_vma_merge(vma, next); 8371da177e4SLinus Torvalds mm->map_count--; 8383964acd0SOleg Nesterov mpol_put(vma_policy(next)); 839524e00b3SLiam R. Howlett if (remove_next != 2) 840524e00b3SLiam R. Howlett BUG_ON(vma->vm_end < next->vm_end); 8413928d4f5SLinus Torvalds vm_area_free(next); 842524e00b3SLiam R. Howlett 8431da177e4SLinus Torvalds /* 8441da177e4SLinus Torvalds * In mprotect's case 6 (see comments on vma_merge), 845763ecb03SLiam R. Howlett * we must remove next_next too. 8461da177e4SLinus Torvalds */ 847734537c9SKirill A. Shutemov if (remove_next == 2) { 848734537c9SKirill A. Shutemov remove_next = 1; 849763ecb03SLiam R. Howlett next = next_next; 8501da177e4SLinus Torvalds goto again; 851fb8c41e9SAndrea Arcangeli } 8521da177e4SLinus Torvalds } 8532b144498SSrikar Dronamraju if (insert && file) 8547b2d81d4SIngo Molnar uprobe_mmap(insert); 8551da177e4SLinus Torvalds 8563b0e81a1SLiam R. Howlett mas_destroy(&mas); 8571da177e4SLinus Torvalds validate_mm(mm); 858763ecb03SLiam R. Howlett 8595beb4930SRik van Riel return 0; 8601da177e4SLinus Torvalds } 8611da177e4SLinus Torvalds 8621da177e4SLinus Torvalds /* 8631da177e4SLinus Torvalds * If the vma has a ->close operation then the driver probably needs to release 8641da177e4SLinus Torvalds * per-vma resources, so we don't attempt to merge those. 8651da177e4SLinus Torvalds */ 8661da177e4SLinus Torvalds static inline int is_mergeable_vma(struct vm_area_struct *vma, 86719a809afSAndrea Arcangeli struct file *file, unsigned long vm_flags, 8689a10064fSColin Cross struct vm_userfaultfd_ctx vm_userfaultfd_ctx, 8695c26f6acSSuren Baghdasaryan struct anon_vma_name *anon_name) 8701da177e4SLinus Torvalds { 87134228d47SCyrill Gorcunov /* 87234228d47SCyrill Gorcunov * VM_SOFTDIRTY should not prevent from VMA merging, if we 87334228d47SCyrill Gorcunov * match the flags but dirty bit -- the caller should mark 87434228d47SCyrill Gorcunov * merged VMA as dirty. If dirty bit won't be excluded from 8758bb4e7a2SWei Yang * comparison, we increase pressure on the memory system forcing 87634228d47SCyrill Gorcunov * the kernel to generate new VMAs when old one could be 87734228d47SCyrill Gorcunov * extended instead. 87834228d47SCyrill Gorcunov */ 87934228d47SCyrill Gorcunov if ((vma->vm_flags ^ vm_flags) & ~VM_SOFTDIRTY) 8801da177e4SLinus Torvalds return 0; 8811da177e4SLinus Torvalds if (vma->vm_file != file) 8821da177e4SLinus Torvalds return 0; 8831da177e4SLinus Torvalds if (vma->vm_ops && vma->vm_ops->close) 8841da177e4SLinus Torvalds return 0; 88519a809afSAndrea Arcangeli if (!is_mergeable_vm_userfaultfd_ctx(vma, vm_userfaultfd_ctx)) 88619a809afSAndrea Arcangeli return 0; 8875c26f6acSSuren Baghdasaryan if (!anon_vma_name_eq(anon_vma_name(vma), anon_name)) 8889a10064fSColin Cross return 0; 8891da177e4SLinus Torvalds return 1; 8901da177e4SLinus Torvalds } 8911da177e4SLinus Torvalds 8921da177e4SLinus Torvalds static inline int is_mergeable_anon_vma(struct anon_vma *anon_vma1, 893965f55deSShaohua Li struct anon_vma *anon_vma2, 894965f55deSShaohua Li struct vm_area_struct *vma) 8951da177e4SLinus Torvalds { 896965f55deSShaohua Li /* 897965f55deSShaohua Li * The list_is_singular() test is to avoid merging VMA cloned from 898965f55deSShaohua Li * parents. This can improve scalability caused by anon_vma lock. 899965f55deSShaohua Li */ 900965f55deSShaohua Li if ((!anon_vma1 || !anon_vma2) && (!vma || 901965f55deSShaohua Li list_is_singular(&vma->anon_vma_chain))) 902965f55deSShaohua Li return 1; 903965f55deSShaohua Li return anon_vma1 == anon_vma2; 9041da177e4SLinus Torvalds } 9051da177e4SLinus Torvalds 9061da177e4SLinus Torvalds /* 9071da177e4SLinus Torvalds * Return true if we can merge this (vm_flags,anon_vma,file,vm_pgoff) 9081da177e4SLinus Torvalds * in front of (at a lower virtual address and file offset than) the vma. 9091da177e4SLinus Torvalds * 9101da177e4SLinus Torvalds * We cannot merge two vmas if they have differently assigned (non-NULL) 9111da177e4SLinus Torvalds * anon_vmas, nor if same anon_vma is assigned but offsets incompatible. 9121da177e4SLinus Torvalds * 9131da177e4SLinus Torvalds * We don't check here for the merged mmap wrapping around the end of pagecache 91445e55300SPeter Collingbourne * indices (16TB on ia32) because do_mmap() does not permit mmap's which 9151da177e4SLinus Torvalds * wrap, nor mmaps which cover the final page at index -1UL. 9161da177e4SLinus Torvalds */ 9171da177e4SLinus Torvalds static int 9181da177e4SLinus Torvalds can_vma_merge_before(struct vm_area_struct *vma, unsigned long vm_flags, 91919a809afSAndrea Arcangeli struct anon_vma *anon_vma, struct file *file, 92019a809afSAndrea Arcangeli pgoff_t vm_pgoff, 9219a10064fSColin Cross struct vm_userfaultfd_ctx vm_userfaultfd_ctx, 9225c26f6acSSuren Baghdasaryan struct anon_vma_name *anon_name) 9231da177e4SLinus Torvalds { 9249a10064fSColin Cross if (is_mergeable_vma(vma, file, vm_flags, vm_userfaultfd_ctx, anon_name) && 925965f55deSShaohua Li is_mergeable_anon_vma(anon_vma, vma->anon_vma, vma)) { 9261da177e4SLinus Torvalds if (vma->vm_pgoff == vm_pgoff) 9271da177e4SLinus Torvalds return 1; 9281da177e4SLinus Torvalds } 9291da177e4SLinus Torvalds return 0; 9301da177e4SLinus Torvalds } 9311da177e4SLinus Torvalds 9321da177e4SLinus Torvalds /* 9331da177e4SLinus Torvalds * Return true if we can merge this (vm_flags,anon_vma,file,vm_pgoff) 9341da177e4SLinus Torvalds * beyond (at a higher virtual address and file offset than) the vma. 9351da177e4SLinus Torvalds * 9361da177e4SLinus Torvalds * We cannot merge two vmas if they have differently assigned (non-NULL) 9371da177e4SLinus Torvalds * anon_vmas, nor if same anon_vma is assigned but offsets incompatible. 9381da177e4SLinus Torvalds */ 9391da177e4SLinus Torvalds static int 9401da177e4SLinus Torvalds can_vma_merge_after(struct vm_area_struct *vma, unsigned long vm_flags, 94119a809afSAndrea Arcangeli struct anon_vma *anon_vma, struct file *file, 94219a809afSAndrea Arcangeli pgoff_t vm_pgoff, 9439a10064fSColin Cross struct vm_userfaultfd_ctx vm_userfaultfd_ctx, 9445c26f6acSSuren Baghdasaryan struct anon_vma_name *anon_name) 9451da177e4SLinus Torvalds { 9469a10064fSColin Cross if (is_mergeable_vma(vma, file, vm_flags, vm_userfaultfd_ctx, anon_name) && 947965f55deSShaohua Li is_mergeable_anon_vma(anon_vma, vma->anon_vma, vma)) { 9481da177e4SLinus Torvalds pgoff_t vm_pglen; 949d6e93217SLibin vm_pglen = vma_pages(vma); 9501da177e4SLinus Torvalds if (vma->vm_pgoff + vm_pglen == vm_pgoff) 9511da177e4SLinus Torvalds return 1; 9521da177e4SLinus Torvalds } 9531da177e4SLinus Torvalds return 0; 9541da177e4SLinus Torvalds } 9551da177e4SLinus Torvalds 9561da177e4SLinus Torvalds /* 9579a10064fSColin Cross * Given a mapping request (addr,end,vm_flags,file,pgoff,anon_name), 9589a10064fSColin Cross * figure out whether that can be merged with its predecessor or its 9599a10064fSColin Cross * successor. Or both (it neatly fills a hole). 9601da177e4SLinus Torvalds * 9611da177e4SLinus Torvalds * In most cases - when called for mmap, brk or mremap - [addr,end) is 9621da177e4SLinus Torvalds * certain not to be mapped by the time vma_merge is called; but when 9631da177e4SLinus Torvalds * called for mprotect, it is certain to be already mapped (either at 9641da177e4SLinus Torvalds * an offset within prev, or at the start of next), and the flags of 9651da177e4SLinus Torvalds * this area are about to be changed to vm_flags - and the no-change 9661da177e4SLinus Torvalds * case has already been eliminated. 9671da177e4SLinus Torvalds * 9681da177e4SLinus Torvalds * The following mprotect cases have to be considered, where AAAA is 9691da177e4SLinus Torvalds * the area passed down from mprotect_fixup, never extending beyond one 9701da177e4SLinus Torvalds * vma, PPPPPP is the prev vma specified, and NNNNNN the next vma after: 9711da177e4SLinus Torvalds * 9725d42ab29SWei Yang * AAAA AAAA AAAA 9735d42ab29SWei Yang * PPPPPPNNNNNN PPPPPPNNNNNN PPPPPPNNNNNN 9745d42ab29SWei Yang * cannot merge might become might become 9755d42ab29SWei Yang * PPNNNNNNNNNN PPPPPPPPPPNN 9765d42ab29SWei Yang * mmap, brk or case 4 below case 5 below 9775d42ab29SWei Yang * mremap move: 9785d42ab29SWei Yang * AAAA AAAA 9795d42ab29SWei Yang * PPPP NNNN PPPPNNNNXXXX 9805d42ab29SWei Yang * might become might become 9815d42ab29SWei Yang * PPPPPPPPPPPP 1 or PPPPPPPPPPPP 6 or 9825d42ab29SWei Yang * PPPPPPPPNNNN 2 or PPPPPPPPXXXX 7 or 9835d42ab29SWei Yang * PPPPNNNNNNNN 3 PPPPXXXXXXXX 8 9841da177e4SLinus Torvalds * 9858bb4e7a2SWei Yang * It is important for case 8 that the vma NNNN overlapping the 986e86f15eeSAndrea Arcangeli * region AAAA is never going to extended over XXXX. Instead XXXX must 987e86f15eeSAndrea Arcangeli * be extended in region AAAA and NNNN must be removed. This way in 988e86f15eeSAndrea Arcangeli * all cases where vma_merge succeeds, the moment vma_adjust drops the 989e86f15eeSAndrea Arcangeli * rmap_locks, the properties of the merged vma will be already 990e86f15eeSAndrea Arcangeli * correct for the whole merged range. Some of those properties like 991e86f15eeSAndrea Arcangeli * vm_page_prot/vm_flags may be accessed by rmap_walks and they must 992e86f15eeSAndrea Arcangeli * be correct for the whole merged range immediately after the 993e86f15eeSAndrea Arcangeli * rmap_locks are released. Otherwise if XXXX would be removed and 994e86f15eeSAndrea Arcangeli * NNNN would be extended over the XXXX range, remove_migration_ptes 995e86f15eeSAndrea Arcangeli * or other rmap walkers (if working on addresses beyond the "end" 996e86f15eeSAndrea Arcangeli * parameter) may establish ptes with the wrong permissions of NNNN 997e86f15eeSAndrea Arcangeli * instead of the right permissions of XXXX. 9981da177e4SLinus Torvalds */ 9991da177e4SLinus Torvalds struct vm_area_struct *vma_merge(struct mm_struct *mm, 10001da177e4SLinus Torvalds struct vm_area_struct *prev, unsigned long addr, 10011da177e4SLinus Torvalds unsigned long end, unsigned long vm_flags, 10021da177e4SLinus Torvalds struct anon_vma *anon_vma, struct file *file, 100319a809afSAndrea Arcangeli pgoff_t pgoff, struct mempolicy *policy, 10049a10064fSColin Cross struct vm_userfaultfd_ctx vm_userfaultfd_ctx, 10055c26f6acSSuren Baghdasaryan struct anon_vma_name *anon_name) 10061da177e4SLinus Torvalds { 10071da177e4SLinus Torvalds pgoff_t pglen = (end - addr) >> PAGE_SHIFT; 10081da177e4SLinus Torvalds struct vm_area_struct *area, *next; 10095beb4930SRik van Riel int err; 10101da177e4SLinus Torvalds 10111da177e4SLinus Torvalds /* 10121da177e4SLinus Torvalds * We later require that vma->vm_flags == vm_flags, 10131da177e4SLinus Torvalds * so this tests vma->vm_flags & VM_SPECIAL, too. 10141da177e4SLinus Torvalds */ 10151da177e4SLinus Torvalds if (vm_flags & VM_SPECIAL) 10161da177e4SLinus Torvalds return NULL; 10171da177e4SLinus Torvalds 1018763ecb03SLiam R. Howlett next = find_vma(mm, prev ? prev->vm_end : 0); 10191da177e4SLinus Torvalds area = next; 1020e86f15eeSAndrea Arcangeli if (area && area->vm_end == end) /* cases 6, 7, 8 */ 1021763ecb03SLiam R. Howlett next = find_vma(mm, next->vm_end); 10221da177e4SLinus Torvalds 1023e86f15eeSAndrea Arcangeli /* verify some invariant that must be enforced by the caller */ 1024e86f15eeSAndrea Arcangeli VM_WARN_ON(prev && addr <= prev->vm_start); 1025e86f15eeSAndrea Arcangeli VM_WARN_ON(area && end > area->vm_end); 1026e86f15eeSAndrea Arcangeli VM_WARN_ON(addr >= end); 1027e86f15eeSAndrea Arcangeli 10281da177e4SLinus Torvalds /* 10291da177e4SLinus Torvalds * Can it merge with the predecessor? 10301da177e4SLinus Torvalds */ 10311da177e4SLinus Torvalds if (prev && prev->vm_end == addr && 10321da177e4SLinus Torvalds mpol_equal(vma_policy(prev), policy) && 10331da177e4SLinus Torvalds can_vma_merge_after(prev, vm_flags, 103419a809afSAndrea Arcangeli anon_vma, file, pgoff, 10359a10064fSColin Cross vm_userfaultfd_ctx, anon_name)) { 10361da177e4SLinus Torvalds /* 10371da177e4SLinus Torvalds * OK, it can. Can we now merge in the successor as well? 10381da177e4SLinus Torvalds */ 10391da177e4SLinus Torvalds if (next && end == next->vm_start && 10401da177e4SLinus Torvalds mpol_equal(policy, vma_policy(next)) && 10411da177e4SLinus Torvalds can_vma_merge_before(next, vm_flags, 104219a809afSAndrea Arcangeli anon_vma, file, 104319a809afSAndrea Arcangeli pgoff+pglen, 10449a10064fSColin Cross vm_userfaultfd_ctx, anon_name) && 10451da177e4SLinus Torvalds is_mergeable_anon_vma(prev->anon_vma, 1046965f55deSShaohua Li next->anon_vma, NULL)) { 10471da177e4SLinus Torvalds /* cases 1, 6 */ 1048e86f15eeSAndrea Arcangeli err = __vma_adjust(prev, prev->vm_start, 1049e86f15eeSAndrea Arcangeli next->vm_end, prev->vm_pgoff, NULL, 1050e86f15eeSAndrea Arcangeli prev); 10511da177e4SLinus Torvalds } else /* cases 2, 5, 7 */ 1052e86f15eeSAndrea Arcangeli err = __vma_adjust(prev, prev->vm_start, 1053e86f15eeSAndrea Arcangeli end, prev->vm_pgoff, NULL, prev); 10545beb4930SRik van Riel if (err) 10555beb4930SRik van Riel return NULL; 1056c791576cSYang Shi khugepaged_enter_vma(prev, vm_flags); 10571da177e4SLinus Torvalds return prev; 10581da177e4SLinus Torvalds } 10591da177e4SLinus Torvalds 10601da177e4SLinus Torvalds /* 10611da177e4SLinus Torvalds * Can this new request be merged in front of next? 10621da177e4SLinus Torvalds */ 10631da177e4SLinus Torvalds if (next && end == next->vm_start && 10641da177e4SLinus Torvalds mpol_equal(policy, vma_policy(next)) && 10651da177e4SLinus Torvalds can_vma_merge_before(next, vm_flags, 106619a809afSAndrea Arcangeli anon_vma, file, pgoff+pglen, 10679a10064fSColin Cross vm_userfaultfd_ctx, anon_name)) { 10681da177e4SLinus Torvalds if (prev && addr < prev->vm_end) /* case 4 */ 1069e86f15eeSAndrea Arcangeli err = __vma_adjust(prev, prev->vm_start, 1070e86f15eeSAndrea Arcangeli addr, prev->vm_pgoff, NULL, next); 1071e86f15eeSAndrea Arcangeli else { /* cases 3, 8 */ 1072e86f15eeSAndrea Arcangeli err = __vma_adjust(area, addr, next->vm_end, 1073e86f15eeSAndrea Arcangeli next->vm_pgoff - pglen, NULL, next); 1074e86f15eeSAndrea Arcangeli /* 1075e86f15eeSAndrea Arcangeli * In case 3 area is already equal to next and 1076e86f15eeSAndrea Arcangeli * this is a noop, but in case 8 "area" has 1077e86f15eeSAndrea Arcangeli * been removed and next was expanded over it. 1078e86f15eeSAndrea Arcangeli */ 1079e86f15eeSAndrea Arcangeli area = next; 1080e86f15eeSAndrea Arcangeli } 10815beb4930SRik van Riel if (err) 10825beb4930SRik van Riel return NULL; 1083c791576cSYang Shi khugepaged_enter_vma(area, vm_flags); 10841da177e4SLinus Torvalds return area; 10851da177e4SLinus Torvalds } 10861da177e4SLinus Torvalds 10871da177e4SLinus Torvalds return NULL; 10881da177e4SLinus Torvalds } 10891da177e4SLinus Torvalds 10901da177e4SLinus Torvalds /* 1091b4f315b4SEthon Paul * Rough compatibility check to quickly see if it's even worth looking 1092d0e9fe17SLinus Torvalds * at sharing an anon_vma. 1093d0e9fe17SLinus Torvalds * 1094d0e9fe17SLinus Torvalds * They need to have the same vm_file, and the flags can only differ 1095d0e9fe17SLinus Torvalds * in things that mprotect may change. 1096d0e9fe17SLinus Torvalds * 1097d0e9fe17SLinus Torvalds * NOTE! The fact that we share an anon_vma doesn't _have_ to mean that 1098d0e9fe17SLinus Torvalds * we can merge the two vma's. For example, we refuse to merge a vma if 1099d0e9fe17SLinus Torvalds * there is a vm_ops->close() function, because that indicates that the 1100d0e9fe17SLinus Torvalds * driver is doing some kind of reference counting. But that doesn't 1101d0e9fe17SLinus Torvalds * really matter for the anon_vma sharing case. 1102d0e9fe17SLinus Torvalds */ 1103d0e9fe17SLinus Torvalds static int anon_vma_compatible(struct vm_area_struct *a, struct vm_area_struct *b) 1104d0e9fe17SLinus Torvalds { 1105d0e9fe17SLinus Torvalds return a->vm_end == b->vm_start && 1106d0e9fe17SLinus Torvalds mpol_equal(vma_policy(a), vma_policy(b)) && 1107d0e9fe17SLinus Torvalds a->vm_file == b->vm_file && 11086cb4d9a2SAnshuman Khandual !((a->vm_flags ^ b->vm_flags) & ~(VM_ACCESS_FLAGS | VM_SOFTDIRTY)) && 1109d0e9fe17SLinus Torvalds b->vm_pgoff == a->vm_pgoff + ((b->vm_start - a->vm_start) >> PAGE_SHIFT); 1110d0e9fe17SLinus Torvalds } 1111d0e9fe17SLinus Torvalds 1112d0e9fe17SLinus Torvalds /* 1113d0e9fe17SLinus Torvalds * Do some basic sanity checking to see if we can re-use the anon_vma 1114d0e9fe17SLinus Torvalds * from 'old'. The 'a'/'b' vma's are in VM order - one of them will be 1115d0e9fe17SLinus Torvalds * the same as 'old', the other will be the new one that is trying 1116d0e9fe17SLinus Torvalds * to share the anon_vma. 1117d0e9fe17SLinus Torvalds * 11185b449489SFlorian Rommel * NOTE! This runs with mmap_lock held for reading, so it is possible that 1119d0e9fe17SLinus Torvalds * the anon_vma of 'old' is concurrently in the process of being set up 1120d0e9fe17SLinus Torvalds * by another page fault trying to merge _that_. But that's ok: if it 1121d0e9fe17SLinus Torvalds * is being set up, that automatically means that it will be a singleton 1122d0e9fe17SLinus Torvalds * acceptable for merging, so we can do all of this optimistically. But 11234db0c3c2SJason Low * we do that READ_ONCE() to make sure that we never re-load the pointer. 1124d0e9fe17SLinus Torvalds * 1125d0e9fe17SLinus Torvalds * IOW: that the "list_is_singular()" test on the anon_vma_chain only 1126d0e9fe17SLinus Torvalds * matters for the 'stable anon_vma' case (ie the thing we want to avoid 1127d0e9fe17SLinus Torvalds * is to return an anon_vma that is "complex" due to having gone through 1128d0e9fe17SLinus Torvalds * a fork). 1129d0e9fe17SLinus Torvalds * 1130d0e9fe17SLinus Torvalds * We also make sure that the two vma's are compatible (adjacent, 1131d0e9fe17SLinus Torvalds * and with the same memory policies). That's all stable, even with just 11325b449489SFlorian Rommel * a read lock on the mmap_lock. 1133d0e9fe17SLinus Torvalds */ 1134d0e9fe17SLinus Torvalds static struct anon_vma *reusable_anon_vma(struct vm_area_struct *old, struct vm_area_struct *a, struct vm_area_struct *b) 1135d0e9fe17SLinus Torvalds { 1136d0e9fe17SLinus Torvalds if (anon_vma_compatible(a, b)) { 11374db0c3c2SJason Low struct anon_vma *anon_vma = READ_ONCE(old->anon_vma); 1138d0e9fe17SLinus Torvalds 1139d0e9fe17SLinus Torvalds if (anon_vma && list_is_singular(&old->anon_vma_chain)) 1140d0e9fe17SLinus Torvalds return anon_vma; 1141d0e9fe17SLinus Torvalds } 1142d0e9fe17SLinus Torvalds return NULL; 1143d0e9fe17SLinus Torvalds } 1144d0e9fe17SLinus Torvalds 1145d0e9fe17SLinus Torvalds /* 11461da177e4SLinus Torvalds * find_mergeable_anon_vma is used by anon_vma_prepare, to check 11471da177e4SLinus Torvalds * neighbouring vmas for a suitable anon_vma, before it goes off 11481da177e4SLinus Torvalds * to allocate a new anon_vma. It checks because a repetitive 11491da177e4SLinus Torvalds * sequence of mprotects and faults may otherwise lead to distinct 11501da177e4SLinus Torvalds * anon_vmas being allocated, preventing vma merge in subsequent 11511da177e4SLinus Torvalds * mprotect. 11521da177e4SLinus Torvalds */ 11531da177e4SLinus Torvalds struct anon_vma *find_mergeable_anon_vma(struct vm_area_struct *vma) 11541da177e4SLinus Torvalds { 1155763ecb03SLiam R. Howlett MA_STATE(mas, &vma->vm_mm->mm_mt, vma->vm_end, vma->vm_end); 1156a67c8caaSMiaohe Lin struct anon_vma *anon_vma = NULL; 1157763ecb03SLiam R. Howlett struct vm_area_struct *prev, *next; 11581da177e4SLinus Torvalds 1159a67c8caaSMiaohe Lin /* Try next first. */ 1160763ecb03SLiam R. Howlett next = mas_walk(&mas); 1161763ecb03SLiam R. Howlett if (next) { 1162763ecb03SLiam R. Howlett anon_vma = reusable_anon_vma(next, vma, next); 1163d0e9fe17SLinus Torvalds if (anon_vma) 1164d0e9fe17SLinus Torvalds return anon_vma; 1165a67c8caaSMiaohe Lin } 11661da177e4SLinus Torvalds 1167763ecb03SLiam R. Howlett prev = mas_prev(&mas, 0); 1168763ecb03SLiam R. Howlett VM_BUG_ON_VMA(prev != vma, vma); 1169763ecb03SLiam R. Howlett prev = mas_prev(&mas, 0); 1170a67c8caaSMiaohe Lin /* Try prev next. */ 1171763ecb03SLiam R. Howlett if (prev) 1172763ecb03SLiam R. Howlett anon_vma = reusable_anon_vma(prev, prev, vma); 1173a67c8caaSMiaohe Lin 11741da177e4SLinus Torvalds /* 1175a67c8caaSMiaohe Lin * We might reach here with anon_vma == NULL if we can't find 1176a67c8caaSMiaohe Lin * any reusable anon_vma. 11771da177e4SLinus Torvalds * There's no absolute need to look only at touching neighbours: 11781da177e4SLinus Torvalds * we could search further afield for "compatible" anon_vmas. 11791da177e4SLinus Torvalds * But it would probably just be a waste of time searching, 11801da177e4SLinus Torvalds * or lead to too many vmas hanging off the same anon_vma. 11811da177e4SLinus Torvalds * We're trying to allow mprotect remerging later on, 11821da177e4SLinus Torvalds * not trying to minimize memory used for anon_vmas. 11831da177e4SLinus Torvalds */ 1184a67c8caaSMiaohe Lin return anon_vma; 11851da177e4SLinus Torvalds } 11861da177e4SLinus Torvalds 11871da177e4SLinus Torvalds /* 118840401530SAl Viro * If a hint addr is less than mmap_min_addr change hint to be as 118940401530SAl Viro * low as possible but still greater than mmap_min_addr 119040401530SAl Viro */ 119140401530SAl Viro static inline unsigned long round_hint_to_min(unsigned long hint) 119240401530SAl Viro { 119340401530SAl Viro hint &= PAGE_MASK; 119440401530SAl Viro if (((void *)hint != NULL) && 119540401530SAl Viro (hint < mmap_min_addr)) 119640401530SAl Viro return PAGE_ALIGN(mmap_min_addr); 119740401530SAl Viro return hint; 119840401530SAl Viro } 119940401530SAl Viro 12006aeb2542SMike Rapoport int mlock_future_check(struct mm_struct *mm, unsigned long flags, 1201363ee17fSDavidlohr Bueso unsigned long len) 1202363ee17fSDavidlohr Bueso { 1203363ee17fSDavidlohr Bueso unsigned long locked, lock_limit; 1204363ee17fSDavidlohr Bueso 1205363ee17fSDavidlohr Bueso /* mlock MCL_FUTURE? */ 1206363ee17fSDavidlohr Bueso if (flags & VM_LOCKED) { 1207363ee17fSDavidlohr Bueso locked = len >> PAGE_SHIFT; 1208363ee17fSDavidlohr Bueso locked += mm->locked_vm; 1209363ee17fSDavidlohr Bueso lock_limit = rlimit(RLIMIT_MEMLOCK); 1210363ee17fSDavidlohr Bueso lock_limit >>= PAGE_SHIFT; 1211363ee17fSDavidlohr Bueso if (locked > lock_limit && !capable(CAP_IPC_LOCK)) 1212363ee17fSDavidlohr Bueso return -EAGAIN; 1213363ee17fSDavidlohr Bueso } 1214363ee17fSDavidlohr Bueso return 0; 1215363ee17fSDavidlohr Bueso } 1216363ee17fSDavidlohr Bueso 1217be83bbf8SLinus Torvalds static inline u64 file_mmap_size_max(struct file *file, struct inode *inode) 1218be83bbf8SLinus Torvalds { 1219be83bbf8SLinus Torvalds if (S_ISREG(inode->i_mode)) 1220423913adSLinus Torvalds return MAX_LFS_FILESIZE; 1221be83bbf8SLinus Torvalds 1222be83bbf8SLinus Torvalds if (S_ISBLK(inode->i_mode)) 1223be83bbf8SLinus Torvalds return MAX_LFS_FILESIZE; 1224be83bbf8SLinus Torvalds 122576f34950SIvan Khoronzhuk if (S_ISSOCK(inode->i_mode)) 122676f34950SIvan Khoronzhuk return MAX_LFS_FILESIZE; 122776f34950SIvan Khoronzhuk 1228be83bbf8SLinus Torvalds /* Special "we do even unsigned file positions" case */ 1229be83bbf8SLinus Torvalds if (file->f_mode & FMODE_UNSIGNED_OFFSET) 1230be83bbf8SLinus Torvalds return 0; 1231be83bbf8SLinus Torvalds 1232be83bbf8SLinus Torvalds /* Yes, random drivers might want more. But I'm tired of buggy drivers */ 1233be83bbf8SLinus Torvalds return ULONG_MAX; 1234be83bbf8SLinus Torvalds } 1235be83bbf8SLinus Torvalds 1236be83bbf8SLinus Torvalds static inline bool file_mmap_ok(struct file *file, struct inode *inode, 1237be83bbf8SLinus Torvalds unsigned long pgoff, unsigned long len) 1238be83bbf8SLinus Torvalds { 1239be83bbf8SLinus Torvalds u64 maxsize = file_mmap_size_max(file, inode); 1240be83bbf8SLinus Torvalds 1241be83bbf8SLinus Torvalds if (maxsize && len > maxsize) 1242be83bbf8SLinus Torvalds return false; 1243be83bbf8SLinus Torvalds maxsize -= len; 1244be83bbf8SLinus Torvalds if (pgoff > maxsize >> PAGE_SHIFT) 1245be83bbf8SLinus Torvalds return false; 1246be83bbf8SLinus Torvalds return true; 1247be83bbf8SLinus Torvalds } 1248be83bbf8SLinus Torvalds 124940401530SAl Viro /* 12503e4e28c5SMichel Lespinasse * The caller must write-lock current->mm->mmap_lock. 12511da177e4SLinus Torvalds */ 12521fcfd8dbSOleg Nesterov unsigned long do_mmap(struct file *file, unsigned long addr, 12531da177e4SLinus Torvalds unsigned long len, unsigned long prot, 125445e55300SPeter Collingbourne unsigned long flags, unsigned long pgoff, 125545e55300SPeter Collingbourne unsigned long *populate, struct list_head *uf) 12561da177e4SLinus Torvalds { 12571da177e4SLinus Torvalds struct mm_struct *mm = current->mm; 125845e55300SPeter Collingbourne vm_flags_t vm_flags; 125962b5f7d0SDave Hansen int pkey = 0; 12601da177e4SLinus Torvalds 1261524e00b3SLiam R. Howlett validate_mm(mm); 126241badc15SMichel Lespinasse *populate = 0; 1263bebeb3d6SMichel Lespinasse 1264e37609bbSPiotr Kwapulinski if (!len) 1265e37609bbSPiotr Kwapulinski return -EINVAL; 1266e37609bbSPiotr Kwapulinski 12671da177e4SLinus Torvalds /* 12681da177e4SLinus Torvalds * Does the application expect PROT_READ to imply PROT_EXEC? 12691da177e4SLinus Torvalds * 12701da177e4SLinus Torvalds * (the exception is when the underlying filesystem is noexec 12711da177e4SLinus Torvalds * mounted, in which case we dont add PROT_EXEC.) 12721da177e4SLinus Torvalds */ 12731da177e4SLinus Torvalds if ((prot & PROT_READ) && (current->personality & READ_IMPLIES_EXEC)) 127490f8572bSEric W. Biederman if (!(file && path_noexec(&file->f_path))) 12751da177e4SLinus Torvalds prot |= PROT_EXEC; 12761da177e4SLinus Torvalds 1277a4ff8e86SMichal Hocko /* force arch specific MAP_FIXED handling in get_unmapped_area */ 1278a4ff8e86SMichal Hocko if (flags & MAP_FIXED_NOREPLACE) 1279a4ff8e86SMichal Hocko flags |= MAP_FIXED; 1280a4ff8e86SMichal Hocko 12817cd94146SEric Paris if (!(flags & MAP_FIXED)) 12827cd94146SEric Paris addr = round_hint_to_min(addr); 12837cd94146SEric Paris 12841da177e4SLinus Torvalds /* Careful about overflows.. */ 12851da177e4SLinus Torvalds len = PAGE_ALIGN(len); 12869206de95SAl Viro if (!len) 12871da177e4SLinus Torvalds return -ENOMEM; 12881da177e4SLinus Torvalds 12891da177e4SLinus Torvalds /* offset overflow? */ 12901da177e4SLinus Torvalds if ((pgoff + (len >> PAGE_SHIFT)) < pgoff) 12911da177e4SLinus Torvalds return -EOVERFLOW; 12921da177e4SLinus Torvalds 12931da177e4SLinus Torvalds /* Too many mappings? */ 12941da177e4SLinus Torvalds if (mm->map_count > sysctl_max_map_count) 12951da177e4SLinus Torvalds return -ENOMEM; 12961da177e4SLinus Torvalds 12971da177e4SLinus Torvalds /* Obtain the address to map to. we verify (or select) it and ensure 12981da177e4SLinus Torvalds * that it represents a valid section of the address space. 12991da177e4SLinus Torvalds */ 13001da177e4SLinus Torvalds addr = get_unmapped_area(file, addr, len, pgoff, flags); 1301ff68dac6SGaowei Pu if (IS_ERR_VALUE(addr)) 13021da177e4SLinus Torvalds return addr; 13031da177e4SLinus Torvalds 1304a4ff8e86SMichal Hocko if (flags & MAP_FIXED_NOREPLACE) { 130535e43c5fSLiam Howlett if (find_vma_intersection(mm, addr, addr + len)) 1306a4ff8e86SMichal Hocko return -EEXIST; 1307a4ff8e86SMichal Hocko } 1308a4ff8e86SMichal Hocko 130962b5f7d0SDave Hansen if (prot == PROT_EXEC) { 131062b5f7d0SDave Hansen pkey = execute_only_pkey(mm); 131162b5f7d0SDave Hansen if (pkey < 0) 131262b5f7d0SDave Hansen pkey = 0; 131362b5f7d0SDave Hansen } 131462b5f7d0SDave Hansen 13151da177e4SLinus Torvalds /* Do simple checking here so the lower-level routines won't have 13161da177e4SLinus Torvalds * to. we assume access permissions have been handled by the open 13171da177e4SLinus Torvalds * of the memory object, so we don't do any here. 13181da177e4SLinus Torvalds */ 131945e55300SPeter Collingbourne vm_flags = calc_vm_prot_bits(prot, pkey) | calc_vm_flag_bits(flags) | 13201da177e4SLinus Torvalds mm->def_flags | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC; 13211da177e4SLinus Torvalds 1322cdf7b341SHuang Shijie if (flags & MAP_LOCKED) 13231da177e4SLinus Torvalds if (!can_do_mlock()) 13241da177e4SLinus Torvalds return -EPERM; 1325ba470de4SRik van Riel 1326363ee17fSDavidlohr Bueso if (mlock_future_check(mm, vm_flags, len)) 13271da177e4SLinus Torvalds return -EAGAIN; 13281da177e4SLinus Torvalds 13291da177e4SLinus Torvalds if (file) { 1330077bf22bSOleg Nesterov struct inode *inode = file_inode(file); 13311c972597SDan Williams unsigned long flags_mask; 13321c972597SDan Williams 1333be83bbf8SLinus Torvalds if (!file_mmap_ok(file, inode, pgoff, len)) 1334be83bbf8SLinus Torvalds return -EOVERFLOW; 1335be83bbf8SLinus Torvalds 13361c972597SDan Williams flags_mask = LEGACY_MAP_MASK | file->f_op->mmap_supported_flags; 1337077bf22bSOleg Nesterov 13381da177e4SLinus Torvalds switch (flags & MAP_TYPE) { 13391da177e4SLinus Torvalds case MAP_SHARED: 13401c972597SDan Williams /* 13411c972597SDan Williams * Force use of MAP_SHARED_VALIDATE with non-legacy 13421c972597SDan Williams * flags. E.g. MAP_SYNC is dangerous to use with 13431c972597SDan Williams * MAP_SHARED as you don't know which consistency model 13441c972597SDan Williams * you will get. We silently ignore unsupported flags 13451c972597SDan Williams * with MAP_SHARED to preserve backward compatibility. 13461c972597SDan Williams */ 13471c972597SDan Williams flags &= LEGACY_MAP_MASK; 1348e4a9bc58SJoe Perches fallthrough; 13491c972597SDan Williams case MAP_SHARED_VALIDATE: 13501c972597SDan Williams if (flags & ~flags_mask) 13511c972597SDan Williams return -EOPNOTSUPP; 1352dc617f29SDarrick J. Wong if (prot & PROT_WRITE) { 1353dc617f29SDarrick J. Wong if (!(file->f_mode & FMODE_WRITE)) 13541da177e4SLinus Torvalds return -EACCES; 1355dc617f29SDarrick J. Wong if (IS_SWAPFILE(file->f_mapping->host)) 1356dc617f29SDarrick J. Wong return -ETXTBSY; 1357dc617f29SDarrick J. Wong } 13581da177e4SLinus Torvalds 13591da177e4SLinus Torvalds /* 13601da177e4SLinus Torvalds * Make sure we don't allow writing to an append-only 13611da177e4SLinus Torvalds * file.. 13621da177e4SLinus Torvalds */ 13631da177e4SLinus Torvalds if (IS_APPEND(inode) && (file->f_mode & FMODE_WRITE)) 13641da177e4SLinus Torvalds return -EACCES; 13651da177e4SLinus Torvalds 13661da177e4SLinus Torvalds vm_flags |= VM_SHARED | VM_MAYSHARE; 13671da177e4SLinus Torvalds if (!(file->f_mode & FMODE_WRITE)) 13681da177e4SLinus Torvalds vm_flags &= ~(VM_MAYWRITE | VM_SHARED); 1369e4a9bc58SJoe Perches fallthrough; 13701da177e4SLinus Torvalds case MAP_PRIVATE: 13711da177e4SLinus Torvalds if (!(file->f_mode & FMODE_READ)) 13721da177e4SLinus Torvalds return -EACCES; 137390f8572bSEric W. Biederman if (path_noexec(&file->f_path)) { 137480c5606cSLinus Torvalds if (vm_flags & VM_EXEC) 137580c5606cSLinus Torvalds return -EPERM; 137680c5606cSLinus Torvalds vm_flags &= ~VM_MAYEXEC; 137780c5606cSLinus Torvalds } 137880c5606cSLinus Torvalds 137972c2d531SAl Viro if (!file->f_op->mmap) 138080c5606cSLinus Torvalds return -ENODEV; 1381b2c56e4fSOleg Nesterov if (vm_flags & (VM_GROWSDOWN|VM_GROWSUP)) 1382b2c56e4fSOleg Nesterov return -EINVAL; 13831da177e4SLinus Torvalds break; 13841da177e4SLinus Torvalds 13851da177e4SLinus Torvalds default: 13861da177e4SLinus Torvalds return -EINVAL; 13871da177e4SLinus Torvalds } 13881da177e4SLinus Torvalds } else { 13891da177e4SLinus Torvalds switch (flags & MAP_TYPE) { 13901da177e4SLinus Torvalds case MAP_SHARED: 1391b2c56e4fSOleg Nesterov if (vm_flags & (VM_GROWSDOWN|VM_GROWSUP)) 1392b2c56e4fSOleg Nesterov return -EINVAL; 1393ce363942STejun Heo /* 1394ce363942STejun Heo * Ignore pgoff. 1395ce363942STejun Heo */ 1396ce363942STejun Heo pgoff = 0; 13971da177e4SLinus Torvalds vm_flags |= VM_SHARED | VM_MAYSHARE; 13981da177e4SLinus Torvalds break; 13991da177e4SLinus Torvalds case MAP_PRIVATE: 14001da177e4SLinus Torvalds /* 14011da177e4SLinus Torvalds * Set pgoff according to addr for anon_vma. 14021da177e4SLinus Torvalds */ 14031da177e4SLinus Torvalds pgoff = addr >> PAGE_SHIFT; 14041da177e4SLinus Torvalds break; 14051da177e4SLinus Torvalds default: 14061da177e4SLinus Torvalds return -EINVAL; 14071da177e4SLinus Torvalds } 14081da177e4SLinus Torvalds } 14091da177e4SLinus Torvalds 1410c22c0d63SMichel Lespinasse /* 1411c22c0d63SMichel Lespinasse * Set 'VM_NORESERVE' if we should not account for the 1412c22c0d63SMichel Lespinasse * memory use of this mapping. 1413c22c0d63SMichel Lespinasse */ 1414c22c0d63SMichel Lespinasse if (flags & MAP_NORESERVE) { 1415c22c0d63SMichel Lespinasse /* We honor MAP_NORESERVE if allowed to overcommit */ 1416c22c0d63SMichel Lespinasse if (sysctl_overcommit_memory != OVERCOMMIT_NEVER) 1417c22c0d63SMichel Lespinasse vm_flags |= VM_NORESERVE; 1418c22c0d63SMichel Lespinasse 1419c22c0d63SMichel Lespinasse /* hugetlb applies strict overcommit unless MAP_NORESERVE */ 1420c22c0d63SMichel Lespinasse if (file && is_file_hugepages(file)) 1421c22c0d63SMichel Lespinasse vm_flags |= VM_NORESERVE; 1422c22c0d63SMichel Lespinasse } 1423c22c0d63SMichel Lespinasse 1424897ab3e0SMike Rapoport addr = mmap_region(file, addr, len, vm_flags, pgoff, uf); 142509a9f1d2SMichel Lespinasse if (!IS_ERR_VALUE(addr) && 142609a9f1d2SMichel Lespinasse ((vm_flags & VM_LOCKED) || 142709a9f1d2SMichel Lespinasse (flags & (MAP_POPULATE | MAP_NONBLOCK)) == MAP_POPULATE)) 142841badc15SMichel Lespinasse *populate = len; 1429bebeb3d6SMichel Lespinasse return addr; 14300165ab44SMiklos Szeredi } 14316be5ceb0SLinus Torvalds 1432a90f590aSDominik Brodowski unsigned long ksys_mmap_pgoff(unsigned long addr, unsigned long len, 1433a90f590aSDominik Brodowski unsigned long prot, unsigned long flags, 1434a90f590aSDominik Brodowski unsigned long fd, unsigned long pgoff) 143566f0dc48SHugh Dickins { 143666f0dc48SHugh Dickins struct file *file = NULL; 14371e3ee14bSChen Gang unsigned long retval; 143866f0dc48SHugh Dickins 143966f0dc48SHugh Dickins if (!(flags & MAP_ANONYMOUS)) { 1440120a795dSAl Viro audit_mmap_fd(fd, flags); 144166f0dc48SHugh Dickins file = fget(fd); 144266f0dc48SHugh Dickins if (!file) 14431e3ee14bSChen Gang return -EBADF; 14447bba8f0eSZhen Lei if (is_file_hugepages(file)) { 1445af73e4d9SNaoya Horiguchi len = ALIGN(len, huge_page_size(hstate_file(file))); 14467bba8f0eSZhen Lei } else if (unlikely(flags & MAP_HUGETLB)) { 1447493af578SJörn Engel retval = -EINVAL; 1448493af578SJörn Engel goto out_fput; 14497bba8f0eSZhen Lei } 145066f0dc48SHugh Dickins } else if (flags & MAP_HUGETLB) { 1451c103a4dcSAndrew Morton struct hstate *hs; 1452af73e4d9SNaoya Horiguchi 145320ac2893SAnshuman Khandual hs = hstate_sizelog((flags >> MAP_HUGE_SHIFT) & MAP_HUGE_MASK); 1454091d0d55SLi Zefan if (!hs) 1455091d0d55SLi Zefan return -EINVAL; 1456091d0d55SLi Zefan 1457091d0d55SLi Zefan len = ALIGN(len, huge_page_size(hs)); 145866f0dc48SHugh Dickins /* 145966f0dc48SHugh Dickins * VM_NORESERVE is used because the reservations will be 146066f0dc48SHugh Dickins * taken when vm_ops->mmap() is called 146166f0dc48SHugh Dickins */ 1462af73e4d9SNaoya Horiguchi file = hugetlb_file_setup(HUGETLB_ANON_FILE, len, 146342d7395fSAndi Kleen VM_NORESERVE, 146483c1fd76Szhangyiru HUGETLB_ANONHUGE_INODE, 146542d7395fSAndi Kleen (flags >> MAP_HUGE_SHIFT) & MAP_HUGE_MASK); 146666f0dc48SHugh Dickins if (IS_ERR(file)) 146766f0dc48SHugh Dickins return PTR_ERR(file); 146866f0dc48SHugh Dickins } 146966f0dc48SHugh Dickins 14709fbeb5abSMichal Hocko retval = vm_mmap_pgoff(file, addr, len, prot, flags, pgoff); 1471493af578SJörn Engel out_fput: 147266f0dc48SHugh Dickins if (file) 147366f0dc48SHugh Dickins fput(file); 147466f0dc48SHugh Dickins return retval; 147566f0dc48SHugh Dickins } 147666f0dc48SHugh Dickins 1477a90f590aSDominik Brodowski SYSCALL_DEFINE6(mmap_pgoff, unsigned long, addr, unsigned long, len, 1478a90f590aSDominik Brodowski unsigned long, prot, unsigned long, flags, 1479a90f590aSDominik Brodowski unsigned long, fd, unsigned long, pgoff) 1480a90f590aSDominik Brodowski { 1481a90f590aSDominik Brodowski return ksys_mmap_pgoff(addr, len, prot, flags, fd, pgoff); 1482a90f590aSDominik Brodowski } 1483a90f590aSDominik Brodowski 1484a4679373SChristoph Hellwig #ifdef __ARCH_WANT_SYS_OLD_MMAP 1485a4679373SChristoph Hellwig struct mmap_arg_struct { 1486a4679373SChristoph Hellwig unsigned long addr; 1487a4679373SChristoph Hellwig unsigned long len; 1488a4679373SChristoph Hellwig unsigned long prot; 1489a4679373SChristoph Hellwig unsigned long flags; 1490a4679373SChristoph Hellwig unsigned long fd; 1491a4679373SChristoph Hellwig unsigned long offset; 1492a4679373SChristoph Hellwig }; 1493a4679373SChristoph Hellwig 1494a4679373SChristoph Hellwig SYSCALL_DEFINE1(old_mmap, struct mmap_arg_struct __user *, arg) 1495a4679373SChristoph Hellwig { 1496a4679373SChristoph Hellwig struct mmap_arg_struct a; 1497a4679373SChristoph Hellwig 1498a4679373SChristoph Hellwig if (copy_from_user(&a, arg, sizeof(a))) 1499a4679373SChristoph Hellwig return -EFAULT; 1500de1741a1SAlexander Kuleshov if (offset_in_page(a.offset)) 1501a4679373SChristoph Hellwig return -EINVAL; 1502a4679373SChristoph Hellwig 1503a90f590aSDominik Brodowski return ksys_mmap_pgoff(a.addr, a.len, a.prot, a.flags, a.fd, 1504a4679373SChristoph Hellwig a.offset >> PAGE_SHIFT); 1505a4679373SChristoph Hellwig } 1506a4679373SChristoph Hellwig #endif /* __ARCH_WANT_SYS_OLD_MMAP */ 1507a4679373SChristoph Hellwig 15084e950f6fSAlexey Dobriyan /* 15098bb4e7a2SWei Yang * Some shared mappings will want the pages marked read-only 15104e950f6fSAlexey Dobriyan * to track write events. If so, we'll downgrade vm_page_prot 15114e950f6fSAlexey Dobriyan * to the private version (using protection_map[] without the 15124e950f6fSAlexey Dobriyan * VM_SHARED bit). 15134e950f6fSAlexey Dobriyan */ 15146d2329f8SAndrea Arcangeli int vma_wants_writenotify(struct vm_area_struct *vma, pgprot_t vm_page_prot) 15154e950f6fSAlexey Dobriyan { 1516ca16d140SKOSAKI Motohiro vm_flags_t vm_flags = vma->vm_flags; 15178a04446aSKirill A. Shutemov const struct vm_operations_struct *vm_ops = vma->vm_ops; 15184e950f6fSAlexey Dobriyan 15194e950f6fSAlexey Dobriyan /* If it was private or non-writable, the write bit is already clear */ 15204e950f6fSAlexey Dobriyan if ((vm_flags & (VM_WRITE|VM_SHARED)) != ((VM_WRITE|VM_SHARED))) 15214e950f6fSAlexey Dobriyan return 0; 15224e950f6fSAlexey Dobriyan 15234e950f6fSAlexey Dobriyan /* The backer wishes to know when pages are first written to? */ 15248a04446aSKirill A. Shutemov if (vm_ops && (vm_ops->page_mkwrite || vm_ops->pfn_mkwrite)) 15254e950f6fSAlexey Dobriyan return 1; 15264e950f6fSAlexey Dobriyan 152764e45507SPeter Feiner /* The open routine did something to the protections that pgprot_modify 152864e45507SPeter Feiner * won't preserve? */ 15296d2329f8SAndrea Arcangeli if (pgprot_val(vm_page_prot) != 15306d2329f8SAndrea Arcangeli pgprot_val(vm_pgprot_modify(vm_page_prot, vm_flags))) 15314e950f6fSAlexey Dobriyan return 0; 15324e950f6fSAlexey Dobriyan 1533f96f7a40SDavid Hildenbrand /* 1534f96f7a40SDavid Hildenbrand * Do we need to track softdirty? hugetlb does not support softdirty 1535f96f7a40SDavid Hildenbrand * tracking yet. 1536f96f7a40SDavid Hildenbrand */ 1537f96f7a40SDavid Hildenbrand if (vma_soft_dirty_enabled(vma) && !is_vm_hugetlb_page(vma)) 153864e45507SPeter Feiner return 1; 153964e45507SPeter Feiner 15404e950f6fSAlexey Dobriyan /* Specialty mapping? */ 15414b6e1e37SKonstantin Khlebnikov if (vm_flags & VM_PFNMAP) 15424e950f6fSAlexey Dobriyan return 0; 15434e950f6fSAlexey Dobriyan 15444e950f6fSAlexey Dobriyan /* Can the mapping track the dirty pages? */ 15454e950f6fSAlexey Dobriyan return vma->vm_file && vma->vm_file->f_mapping && 1546f56753acSChristoph Hellwig mapping_can_writeback(vma->vm_file->f_mapping); 15474e950f6fSAlexey Dobriyan } 15484e950f6fSAlexey Dobriyan 1549fc8744adSLinus Torvalds /* 1550fc8744adSLinus Torvalds * We account for memory if it's a private writeable mapping, 15515a6fe125SMel Gorman * not hugepages and VM_NORESERVE wasn't set. 1552fc8744adSLinus Torvalds */ 1553ca16d140SKOSAKI Motohiro static inline int accountable_mapping(struct file *file, vm_flags_t vm_flags) 1554fc8744adSLinus Torvalds { 15555a6fe125SMel Gorman /* 15565a6fe125SMel Gorman * hugetlb has its own accounting separate from the core VM 15575a6fe125SMel Gorman * VM_HUGETLB may not be set yet so we cannot check for that flag. 15585a6fe125SMel Gorman */ 15595a6fe125SMel Gorman if (file && is_file_hugepages(file)) 15605a6fe125SMel Gorman return 0; 15615a6fe125SMel Gorman 1562fc8744adSLinus Torvalds return (vm_flags & (VM_NORESERVE | VM_SHARED | VM_WRITE)) == VM_WRITE; 1563fc8744adSLinus Torvalds } 1564fc8744adSLinus Torvalds 15653499a131SLiam R. Howlett /** 15663499a131SLiam R. Howlett * unmapped_area() - Find an area between the low_limit and the high_limit with 15673499a131SLiam R. Howlett * the correct alignment and offset, all from @info. Note: current->mm is used 15683499a131SLiam R. Howlett * for the search. 15693499a131SLiam R. Howlett * 15703499a131SLiam R. Howlett * @info: The unmapped area information including the range (low_limit - 15713499a131SLiam R. Howlett * hight_limit), the alignment offset and mask. 15723499a131SLiam R. Howlett * 15733499a131SLiam R. Howlett * Return: A memory address or -ENOMEM. 15743499a131SLiam R. Howlett */ 1575baceaf1cSJaewon Kim static unsigned long unmapped_area(struct vm_unmapped_area_info *info) 1576db4fbfb9SMichel Lespinasse { 15773499a131SLiam R. Howlett unsigned long length, gap; 1578db4fbfb9SMichel Lespinasse 15793499a131SLiam R. Howlett MA_STATE(mas, ¤t->mm->mm_mt, 0, 0); 1580db4fbfb9SMichel Lespinasse 1581db4fbfb9SMichel Lespinasse /* Adjust search length to account for worst case alignment overhead */ 1582db4fbfb9SMichel Lespinasse length = info->length + info->align_mask; 1583db4fbfb9SMichel Lespinasse if (length < info->length) 1584db4fbfb9SMichel Lespinasse return -ENOMEM; 1585db4fbfb9SMichel Lespinasse 15863499a131SLiam R. Howlett if (mas_empty_area(&mas, info->low_limit, info->high_limit - 1, 15873499a131SLiam R. Howlett length)) 15883499a131SLiam R. Howlett return -ENOMEM; 15893499a131SLiam R. Howlett 1590d4af56c5SLiam R. Howlett gap = mas.index; 1591d4af56c5SLiam R. Howlett gap += (info->align_offset - gap) & info->align_mask; 15923499a131SLiam R. Howlett return gap; 1593db4fbfb9SMichel Lespinasse } 1594db4fbfb9SMichel Lespinasse 15953499a131SLiam R. Howlett /** 15963499a131SLiam R. Howlett * unmapped_area_topdown() - Find an area between the low_limit and the 15973499a131SLiam R. Howlett * high_limit with * the correct alignment and offset at the highest available 15983499a131SLiam R. Howlett * address, all from @info. Note: current->mm is used for the search. 15993499a131SLiam R. Howlett * 16003499a131SLiam R. Howlett * @info: The unmapped area information including the range (low_limit - 16013499a131SLiam R. Howlett * hight_limit), the alignment offset and mask. 16023499a131SLiam R. Howlett * 16033499a131SLiam R. Howlett * Return: A memory address or -ENOMEM. 16043499a131SLiam R. Howlett */ 1605baceaf1cSJaewon Kim static unsigned long unmapped_area_topdown(struct vm_unmapped_area_info *info) 1606db4fbfb9SMichel Lespinasse { 16073499a131SLiam R. Howlett unsigned long length, gap; 1608d4af56c5SLiam R. Howlett 16093499a131SLiam R. Howlett MA_STATE(mas, ¤t->mm->mm_mt, 0, 0); 1610db4fbfb9SMichel Lespinasse /* Adjust search length to account for worst case alignment overhead */ 1611db4fbfb9SMichel Lespinasse length = info->length + info->align_mask; 1612db4fbfb9SMichel Lespinasse if (length < info->length) 1613db4fbfb9SMichel Lespinasse return -ENOMEM; 1614db4fbfb9SMichel Lespinasse 16153499a131SLiam R. Howlett if (mas_empty_area_rev(&mas, info->low_limit, info->high_limit - 1, 16163499a131SLiam R. Howlett length)) 16173499a131SLiam R. Howlett return -ENOMEM; 16183499a131SLiam R. Howlett 1619d4af56c5SLiam R. Howlett gap = mas.last + 1 - info->length; 1620d4af56c5SLiam R. Howlett gap -= (gap - info->align_offset) & info->align_mask; 16213499a131SLiam R. Howlett return gap; 1622db4fbfb9SMichel Lespinasse } 1623db4fbfb9SMichel Lespinasse 1624baceaf1cSJaewon Kim /* 1625baceaf1cSJaewon Kim * Search for an unmapped address range. 1626baceaf1cSJaewon Kim * 1627baceaf1cSJaewon Kim * We are looking for a range that: 1628baceaf1cSJaewon Kim * - does not intersect with any VMA; 1629baceaf1cSJaewon Kim * - is contained within the [low_limit, high_limit) interval; 1630baceaf1cSJaewon Kim * - is at least the desired size. 1631baceaf1cSJaewon Kim * - satisfies (begin_addr & align_mask) == (align_offset & align_mask) 1632baceaf1cSJaewon Kim */ 1633baceaf1cSJaewon Kim unsigned long vm_unmapped_area(struct vm_unmapped_area_info *info) 1634baceaf1cSJaewon Kim { 1635df529cabSJaewon Kim unsigned long addr; 1636df529cabSJaewon Kim 1637baceaf1cSJaewon Kim if (info->flags & VM_UNMAPPED_AREA_TOPDOWN) 1638df529cabSJaewon Kim addr = unmapped_area_topdown(info); 1639baceaf1cSJaewon Kim else 1640df529cabSJaewon Kim addr = unmapped_area(info); 1641df529cabSJaewon Kim 1642df529cabSJaewon Kim trace_vm_unmapped_area(addr, info); 1643df529cabSJaewon Kim return addr; 1644baceaf1cSJaewon Kim } 1645f6795053SSteve Capper 16461da177e4SLinus Torvalds /* Get an address range which is currently unmapped. 16471da177e4SLinus Torvalds * For shmat() with addr=0. 16481da177e4SLinus Torvalds * 16491da177e4SLinus Torvalds * Ugly calling convention alert: 16501da177e4SLinus Torvalds * Return value with the low bits set means error value, 16511da177e4SLinus Torvalds * ie 16521da177e4SLinus Torvalds * if (ret & ~PAGE_MASK) 16531da177e4SLinus Torvalds * error = ret; 16541da177e4SLinus Torvalds * 16551da177e4SLinus Torvalds * This function "knows" that -ENOMEM has the bits set. 16561da177e4SLinus Torvalds */ 16571da177e4SLinus Torvalds unsigned long 16584b439e25SChristophe Leroy generic_get_unmapped_area(struct file *filp, unsigned long addr, 16594b439e25SChristophe Leroy unsigned long len, unsigned long pgoff, 16604b439e25SChristophe Leroy unsigned long flags) 16611da177e4SLinus Torvalds { 16621da177e4SLinus Torvalds struct mm_struct *mm = current->mm; 16631be7107fSHugh Dickins struct vm_area_struct *vma, *prev; 1664db4fbfb9SMichel Lespinasse struct vm_unmapped_area_info info; 16652cb4de08SChristophe Leroy const unsigned long mmap_end = arch_get_mmap_end(addr, len, flags); 16661da177e4SLinus Torvalds 1667f6795053SSteve Capper if (len > mmap_end - mmap_min_addr) 16681da177e4SLinus Torvalds return -ENOMEM; 16691da177e4SLinus Torvalds 167006abdfb4SBenjamin Herrenschmidt if (flags & MAP_FIXED) 167106abdfb4SBenjamin Herrenschmidt return addr; 167206abdfb4SBenjamin Herrenschmidt 16731da177e4SLinus Torvalds if (addr) { 16741da177e4SLinus Torvalds addr = PAGE_ALIGN(addr); 16751be7107fSHugh Dickins vma = find_vma_prev(mm, addr, &prev); 1676f6795053SSteve Capper if (mmap_end - len >= addr && addr >= mmap_min_addr && 16771be7107fSHugh Dickins (!vma || addr + len <= vm_start_gap(vma)) && 16781be7107fSHugh Dickins (!prev || addr >= vm_end_gap(prev))) 16791da177e4SLinus Torvalds return addr; 16801da177e4SLinus Torvalds } 16811da177e4SLinus Torvalds 1682db4fbfb9SMichel Lespinasse info.flags = 0; 1683db4fbfb9SMichel Lespinasse info.length = len; 16844e99b021SHeiko Carstens info.low_limit = mm->mmap_base; 1685f6795053SSteve Capper info.high_limit = mmap_end; 1686db4fbfb9SMichel Lespinasse info.align_mask = 0; 168709ef5283SJaewon Kim info.align_offset = 0; 1688db4fbfb9SMichel Lespinasse return vm_unmapped_area(&info); 16891da177e4SLinus Torvalds } 16904b439e25SChristophe Leroy 16914b439e25SChristophe Leroy #ifndef HAVE_ARCH_UNMAPPED_AREA 16924b439e25SChristophe Leroy unsigned long 16934b439e25SChristophe Leroy arch_get_unmapped_area(struct file *filp, unsigned long addr, 16944b439e25SChristophe Leroy unsigned long len, unsigned long pgoff, 16954b439e25SChristophe Leroy unsigned long flags) 16964b439e25SChristophe Leroy { 16974b439e25SChristophe Leroy return generic_get_unmapped_area(filp, addr, len, pgoff, flags); 16984b439e25SChristophe Leroy } 16991da177e4SLinus Torvalds #endif 17001da177e4SLinus Torvalds 17011da177e4SLinus Torvalds /* 17021da177e4SLinus Torvalds * This mmap-allocator allocates new areas top-down from below the 17031da177e4SLinus Torvalds * stack's low limit (the base): 17041da177e4SLinus Torvalds */ 17051da177e4SLinus Torvalds unsigned long 17064b439e25SChristophe Leroy generic_get_unmapped_area_topdown(struct file *filp, unsigned long addr, 170743cca0b1SYang Fan unsigned long len, unsigned long pgoff, 170843cca0b1SYang Fan unsigned long flags) 17091da177e4SLinus Torvalds { 17101be7107fSHugh Dickins struct vm_area_struct *vma, *prev; 17111da177e4SLinus Torvalds struct mm_struct *mm = current->mm; 1712db4fbfb9SMichel Lespinasse struct vm_unmapped_area_info info; 17132cb4de08SChristophe Leroy const unsigned long mmap_end = arch_get_mmap_end(addr, len, flags); 17141da177e4SLinus Torvalds 17151da177e4SLinus Torvalds /* requested length too big for entire address space */ 1716f6795053SSteve Capper if (len > mmap_end - mmap_min_addr) 17171da177e4SLinus Torvalds return -ENOMEM; 17181da177e4SLinus Torvalds 171906abdfb4SBenjamin Herrenschmidt if (flags & MAP_FIXED) 172006abdfb4SBenjamin Herrenschmidt return addr; 172106abdfb4SBenjamin Herrenschmidt 17221da177e4SLinus Torvalds /* requesting a specific address */ 17231da177e4SLinus Torvalds if (addr) { 17241da177e4SLinus Torvalds addr = PAGE_ALIGN(addr); 17251be7107fSHugh Dickins vma = find_vma_prev(mm, addr, &prev); 1726f6795053SSteve Capper if (mmap_end - len >= addr && addr >= mmap_min_addr && 17271be7107fSHugh Dickins (!vma || addr + len <= vm_start_gap(vma)) && 17281be7107fSHugh Dickins (!prev || addr >= vm_end_gap(prev))) 17291da177e4SLinus Torvalds return addr; 17301da177e4SLinus Torvalds } 17311da177e4SLinus Torvalds 1732db4fbfb9SMichel Lespinasse info.flags = VM_UNMAPPED_AREA_TOPDOWN; 1733db4fbfb9SMichel Lespinasse info.length = len; 17342afc745fSAkira Takeuchi info.low_limit = max(PAGE_SIZE, mmap_min_addr); 1735f6795053SSteve Capper info.high_limit = arch_get_mmap_base(addr, mm->mmap_base); 1736db4fbfb9SMichel Lespinasse info.align_mask = 0; 173709ef5283SJaewon Kim info.align_offset = 0; 1738db4fbfb9SMichel Lespinasse addr = vm_unmapped_area(&info); 1739b716ad95SXiao Guangrong 17401da177e4SLinus Torvalds /* 17411da177e4SLinus Torvalds * A failed mmap() very likely causes application failure, 17421da177e4SLinus Torvalds * so fall back to the bottom-up function here. This scenario 17431da177e4SLinus Torvalds * can happen with large stack limits and large mmap() 17441da177e4SLinus Torvalds * allocations. 17451da177e4SLinus Torvalds */ 1746de1741a1SAlexander Kuleshov if (offset_in_page(addr)) { 1747db4fbfb9SMichel Lespinasse VM_BUG_ON(addr != -ENOMEM); 1748db4fbfb9SMichel Lespinasse info.flags = 0; 1749db4fbfb9SMichel Lespinasse info.low_limit = TASK_UNMAPPED_BASE; 1750f6795053SSteve Capper info.high_limit = mmap_end; 1751db4fbfb9SMichel Lespinasse addr = vm_unmapped_area(&info); 1752db4fbfb9SMichel Lespinasse } 17531da177e4SLinus Torvalds 17541da177e4SLinus Torvalds return addr; 17551da177e4SLinus Torvalds } 17564b439e25SChristophe Leroy 17574b439e25SChristophe Leroy #ifndef HAVE_ARCH_UNMAPPED_AREA_TOPDOWN 17584b439e25SChristophe Leroy unsigned long 17594b439e25SChristophe Leroy arch_get_unmapped_area_topdown(struct file *filp, unsigned long addr, 17604b439e25SChristophe Leroy unsigned long len, unsigned long pgoff, 17614b439e25SChristophe Leroy unsigned long flags) 17624b439e25SChristophe Leroy { 17634b439e25SChristophe Leroy return generic_get_unmapped_area_topdown(filp, addr, len, pgoff, flags); 17644b439e25SChristophe Leroy } 17651da177e4SLinus Torvalds #endif 17661da177e4SLinus Torvalds 17671da177e4SLinus Torvalds unsigned long 17681da177e4SLinus Torvalds get_unmapped_area(struct file *file, unsigned long addr, unsigned long len, 17691da177e4SLinus Torvalds unsigned long pgoff, unsigned long flags) 17701da177e4SLinus Torvalds { 177106abdfb4SBenjamin Herrenschmidt unsigned long (*get_area)(struct file *, unsigned long, 177206abdfb4SBenjamin Herrenschmidt unsigned long, unsigned long, unsigned long); 177307ab67c8SLinus Torvalds 17749206de95SAl Viro unsigned long error = arch_mmap_check(addr, len, flags); 17759206de95SAl Viro if (error) 17769206de95SAl Viro return error; 17779206de95SAl Viro 17789206de95SAl Viro /* Careful about overflows.. */ 17799206de95SAl Viro if (len > TASK_SIZE) 17809206de95SAl Viro return -ENOMEM; 17819206de95SAl Viro 178207ab67c8SLinus Torvalds get_area = current->mm->get_unmapped_area; 1783c01d5b30SHugh Dickins if (file) { 1784c01d5b30SHugh Dickins if (file->f_op->get_unmapped_area) 178507ab67c8SLinus Torvalds get_area = file->f_op->get_unmapped_area; 1786c01d5b30SHugh Dickins } else if (flags & MAP_SHARED) { 1787c01d5b30SHugh Dickins /* 1788c01d5b30SHugh Dickins * mmap_region() will call shmem_zero_setup() to create a file, 1789c01d5b30SHugh Dickins * so use shmem's get_unmapped_area in case it can be huge. 179045e55300SPeter Collingbourne * do_mmap() will clear pgoff, so match alignment. 1791c01d5b30SHugh Dickins */ 1792c01d5b30SHugh Dickins pgoff = 0; 1793c01d5b30SHugh Dickins get_area = shmem_get_unmapped_area; 1794f35b5d7dSRik van Riel } else if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE)) { 1795f35b5d7dSRik van Riel /* Ensures that larger anonymous mappings are THP aligned. */ 1796f35b5d7dSRik van Riel get_area = thp_get_unmapped_area; 1797c01d5b30SHugh Dickins } 1798c01d5b30SHugh Dickins 179907ab67c8SLinus Torvalds addr = get_area(file, addr, len, pgoff, flags); 180007ab67c8SLinus Torvalds if (IS_ERR_VALUE(addr)) 180107ab67c8SLinus Torvalds return addr; 180207ab67c8SLinus Torvalds 18031da177e4SLinus Torvalds if (addr > TASK_SIZE - len) 18041da177e4SLinus Torvalds return -ENOMEM; 1805de1741a1SAlexander Kuleshov if (offset_in_page(addr)) 18061da177e4SLinus Torvalds return -EINVAL; 180706abdfb4SBenjamin Herrenschmidt 18089ac4ed4bSAl Viro error = security_mmap_addr(addr); 18099ac4ed4bSAl Viro return error ? error : addr; 18101da177e4SLinus Torvalds } 18111da177e4SLinus Torvalds 18121da177e4SLinus Torvalds EXPORT_SYMBOL(get_unmapped_area); 18131da177e4SLinus Torvalds 1814be8432e7SLiam R. Howlett /** 1815abdba2ddSLiam R. Howlett * find_vma_intersection() - Look up the first VMA which intersects the interval 1816abdba2ddSLiam R. Howlett * @mm: The process address space. 1817abdba2ddSLiam R. Howlett * @start_addr: The inclusive start user address. 1818abdba2ddSLiam R. Howlett * @end_addr: The exclusive end user address. 1819abdba2ddSLiam R. Howlett * 1820abdba2ddSLiam R. Howlett * Returns: The first VMA within the provided range, %NULL otherwise. Assumes 1821abdba2ddSLiam R. Howlett * start_addr < end_addr. 1822abdba2ddSLiam R. Howlett */ 1823abdba2ddSLiam R. Howlett struct vm_area_struct *find_vma_intersection(struct mm_struct *mm, 1824abdba2ddSLiam R. Howlett unsigned long start_addr, 1825abdba2ddSLiam R. Howlett unsigned long end_addr) 1826abdba2ddSLiam R. Howlett { 1827abdba2ddSLiam R. Howlett unsigned long index = start_addr; 1828abdba2ddSLiam R. Howlett 1829abdba2ddSLiam R. Howlett mmap_assert_locked(mm); 18307964cf8cSLiam R. Howlett return mt_find(&mm->mm_mt, &index, end_addr - 1); 1831abdba2ddSLiam R. Howlett } 1832abdba2ddSLiam R. Howlett EXPORT_SYMBOL(find_vma_intersection); 1833abdba2ddSLiam R. Howlett 1834abdba2ddSLiam R. Howlett /** 1835be8432e7SLiam R. Howlett * find_vma() - Find the VMA for a given address, or the next VMA. 1836be8432e7SLiam R. Howlett * @mm: The mm_struct to check 1837be8432e7SLiam R. Howlett * @addr: The address 1838be8432e7SLiam R. Howlett * 1839be8432e7SLiam R. Howlett * Returns: The VMA associated with addr, or the next VMA. 1840be8432e7SLiam R. Howlett * May return %NULL in the case of no VMA at addr or above. 1841be8432e7SLiam R. Howlett */ 18421da177e4SLinus Torvalds struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr) 18431da177e4SLinus Torvalds { 1844be8432e7SLiam R. Howlett unsigned long index = addr; 18451da177e4SLinus Torvalds 18465b78ed24SLuigi Rizzo mmap_assert_locked(mm); 18477964cf8cSLiam R. Howlett return mt_find(&mm->mm_mt, &index, ULONG_MAX); 18481da177e4SLinus Torvalds } 18491da177e4SLinus Torvalds EXPORT_SYMBOL(find_vma); 18501da177e4SLinus Torvalds 18517fdbd37dSLiam R. Howlett /** 18527fdbd37dSLiam R. Howlett * find_vma_prev() - Find the VMA for a given address, or the next vma and 18537fdbd37dSLiam R. Howlett * set %pprev to the previous VMA, if any. 18547fdbd37dSLiam R. Howlett * @mm: The mm_struct to check 18557fdbd37dSLiam R. Howlett * @addr: The address 18567fdbd37dSLiam R. Howlett * @pprev: The pointer to set to the previous VMA 18577fdbd37dSLiam R. Howlett * 18587fdbd37dSLiam R. Howlett * Note that RCU lock is missing here since the external mmap_lock() is used 18597fdbd37dSLiam R. Howlett * instead. 18607fdbd37dSLiam R. Howlett * 18617fdbd37dSLiam R. Howlett * Returns: The VMA associated with @addr, or the next vma. 18627fdbd37dSLiam R. Howlett * May return %NULL in the case of no vma at addr or above. 18636bd4837dSKOSAKI Motohiro */ 18641da177e4SLinus Torvalds struct vm_area_struct * 18651da177e4SLinus Torvalds find_vma_prev(struct mm_struct *mm, unsigned long addr, 18661da177e4SLinus Torvalds struct vm_area_struct **pprev) 18671da177e4SLinus Torvalds { 18686bd4837dSKOSAKI Motohiro struct vm_area_struct *vma; 18697fdbd37dSLiam R. Howlett MA_STATE(mas, &mm->mm_mt, addr, addr); 18701da177e4SLinus Torvalds 18717fdbd37dSLiam R. Howlett vma = mas_walk(&mas); 18727fdbd37dSLiam R. Howlett *pprev = mas_prev(&mas, 0); 18737fdbd37dSLiam R. Howlett if (!vma) 18747fdbd37dSLiam R. Howlett vma = mas_next(&mas, ULONG_MAX); 18756bd4837dSKOSAKI Motohiro return vma; 18761da177e4SLinus Torvalds } 18771da177e4SLinus Torvalds 18781da177e4SLinus Torvalds /* 18791da177e4SLinus Torvalds * Verify that the stack growth is acceptable and 18801da177e4SLinus Torvalds * update accounting. This is shared with both the 18811da177e4SLinus Torvalds * grow-up and grow-down cases. 18821da177e4SLinus Torvalds */ 18831be7107fSHugh Dickins static int acct_stack_growth(struct vm_area_struct *vma, 18841be7107fSHugh Dickins unsigned long size, unsigned long grow) 18851da177e4SLinus Torvalds { 18861da177e4SLinus Torvalds struct mm_struct *mm = vma->vm_mm; 18871be7107fSHugh Dickins unsigned long new_start; 18881da177e4SLinus Torvalds 18891da177e4SLinus Torvalds /* address space limit tests */ 189084638335SKonstantin Khlebnikov if (!may_expand_vm(mm, vma->vm_flags, grow)) 18911da177e4SLinus Torvalds return -ENOMEM; 18921da177e4SLinus Torvalds 18931da177e4SLinus Torvalds /* Stack limit test */ 189424c79d8eSKrzysztof Opasiak if (size > rlimit(RLIMIT_STACK)) 18951da177e4SLinus Torvalds return -ENOMEM; 18961da177e4SLinus Torvalds 18971da177e4SLinus Torvalds /* mlock limit tests */ 1898c5d8a364SMiaohe Lin if (mlock_future_check(mm, vma->vm_flags, grow << PAGE_SHIFT)) 18991da177e4SLinus Torvalds return -ENOMEM; 19001da177e4SLinus Torvalds 19010d59a01bSAdam Litke /* Check to ensure the stack will not grow into a hugetlb-only region */ 19020d59a01bSAdam Litke new_start = (vma->vm_flags & VM_GROWSUP) ? vma->vm_start : 19030d59a01bSAdam Litke vma->vm_end - size; 19040d59a01bSAdam Litke if (is_hugepage_only_range(vma->vm_mm, new_start, size)) 19050d59a01bSAdam Litke return -EFAULT; 19060d59a01bSAdam Litke 19071da177e4SLinus Torvalds /* 19081da177e4SLinus Torvalds * Overcommit.. This must be the final test, as it will 19091da177e4SLinus Torvalds * update security statistics. 19101da177e4SLinus Torvalds */ 191105fa199dSHugh Dickins if (security_vm_enough_memory_mm(mm, grow)) 19121da177e4SLinus Torvalds return -ENOMEM; 19131da177e4SLinus Torvalds 19141da177e4SLinus Torvalds return 0; 19151da177e4SLinus Torvalds } 19161da177e4SLinus Torvalds 191746dea3d0SHugh Dickins #if defined(CONFIG_STACK_GROWSUP) || defined(CONFIG_IA64) 19181da177e4SLinus Torvalds /* 191946dea3d0SHugh Dickins * PA-RISC uses this for its stack; IA64 for its Register Backing Store. 192046dea3d0SHugh Dickins * vma is the last one with address > vma->vm_end. Have to extend vma. 19211da177e4SLinus Torvalds */ 192246dea3d0SHugh Dickins int expand_upwards(struct vm_area_struct *vma, unsigned long address) 19231da177e4SLinus Torvalds { 192409357814SOleg Nesterov struct mm_struct *mm = vma->vm_mm; 19251be7107fSHugh Dickins struct vm_area_struct *next; 19261be7107fSHugh Dickins unsigned long gap_addr; 192712352d3cSKonstantin Khlebnikov int error = 0; 1928d4af56c5SLiam R. Howlett MA_STATE(mas, &mm->mm_mt, 0, 0); 19291da177e4SLinus Torvalds 19301da177e4SLinus Torvalds if (!(vma->vm_flags & VM_GROWSUP)) 19311da177e4SLinus Torvalds return -EFAULT; 19321da177e4SLinus Torvalds 1933bd726c90SHelge Deller /* Guard against exceeding limits of the address space. */ 19341be7107fSHugh Dickins address &= PAGE_MASK; 193537511fb5SHelge Deller if (address >= (TASK_SIZE & PAGE_MASK)) 193612352d3cSKonstantin Khlebnikov return -ENOMEM; 1937bd726c90SHelge Deller address += PAGE_SIZE; 193812352d3cSKonstantin Khlebnikov 19391be7107fSHugh Dickins /* Enforce stack_guard_gap */ 19401be7107fSHugh Dickins gap_addr = address + stack_guard_gap; 1941bd726c90SHelge Deller 1942bd726c90SHelge Deller /* Guard against overflow */ 1943bd726c90SHelge Deller if (gap_addr < address || gap_addr > TASK_SIZE) 1944bd726c90SHelge Deller gap_addr = TASK_SIZE; 1945bd726c90SHelge Deller 1946763ecb03SLiam R. Howlett next = find_vma_intersection(mm, vma->vm_end, gap_addr); 1947763ecb03SLiam R. Howlett if (next && vma_is_accessible(next)) { 19481be7107fSHugh Dickins if (!(next->vm_flags & VM_GROWSUP)) 19491be7107fSHugh Dickins return -ENOMEM; 19501be7107fSHugh Dickins /* Check that both stack segments have the same anon_vma? */ 19511be7107fSHugh Dickins } 19521be7107fSHugh Dickins 1953d4af56c5SLiam R. Howlett if (mas_preallocate(&mas, vma, GFP_KERNEL)) 19541da177e4SLinus Torvalds return -ENOMEM; 19551da177e4SLinus Torvalds 1956d4af56c5SLiam R. Howlett /* We must make sure the anon_vma is allocated. */ 1957d4af56c5SLiam R. Howlett if (unlikely(anon_vma_prepare(vma))) { 1958d4af56c5SLiam R. Howlett mas_destroy(&mas); 1959d4af56c5SLiam R. Howlett return -ENOMEM; 1960d4af56c5SLiam R. Howlett } 1961d4af56c5SLiam R. Howlett 19621da177e4SLinus Torvalds /* 19631da177e4SLinus Torvalds * vma->vm_start/vm_end cannot change under us because the caller 1964c1e8d7c6SMichel Lespinasse * is required to hold the mmap_lock in read mode. We need the 19651da177e4SLinus Torvalds * anon_vma lock to serialize against concurrent expand_stacks. 19661da177e4SLinus Torvalds */ 196712352d3cSKonstantin Khlebnikov anon_vma_lock_write(vma->anon_vma); 19681da177e4SLinus Torvalds 19691da177e4SLinus Torvalds /* Somebody else might have raced and expanded it already */ 19701da177e4SLinus Torvalds if (address > vma->vm_end) { 19711da177e4SLinus Torvalds unsigned long size, grow; 19721da177e4SLinus Torvalds 19731da177e4SLinus Torvalds size = address - vma->vm_start; 19741da177e4SLinus Torvalds grow = (address - vma->vm_end) >> PAGE_SHIFT; 19751da177e4SLinus Torvalds 197642c36f63SHugh Dickins error = -ENOMEM; 197742c36f63SHugh Dickins if (vma->vm_pgoff + (size >> PAGE_SHIFT) >= vma->vm_pgoff) { 19781da177e4SLinus Torvalds error = acct_stack_growth(vma, size, grow); 19793af9e859SEric B Munson if (!error) { 19804128997bSMichel Lespinasse /* 1981524e00b3SLiam R. Howlett * We only hold a shared mmap_lock lock here, so 1982524e00b3SLiam R. Howlett * we need to protect against concurrent vma 1983524e00b3SLiam R. Howlett * expansions. anon_vma_lock_write() doesn't 1984524e00b3SLiam R. Howlett * help here, as we don't guarantee that all 1985524e00b3SLiam R. Howlett * growable vmas in a mm share the same root 1986524e00b3SLiam R. Howlett * anon vma. So, we reuse mm->page_table_lock 1987524e00b3SLiam R. Howlett * to guard against concurrent vma expansions. 19884128997bSMichel Lespinasse */ 198909357814SOleg Nesterov spin_lock(&mm->page_table_lock); 199087e8827bSOleg Nesterov if (vma->vm_flags & VM_LOCKED) 199109357814SOleg Nesterov mm->locked_vm += grow; 199284638335SKonstantin Khlebnikov vm_stat_account(mm, vma->vm_flags, grow); 1993bf181b9fSMichel Lespinasse anon_vma_interval_tree_pre_update_vma(vma); 19941da177e4SLinus Torvalds vma->vm_end = address; 1995d4af56c5SLiam R. Howlett /* Overwrite old entry in mtree. */ 1996d4af56c5SLiam R. Howlett vma_mas_store(vma, &mas); 1997bf181b9fSMichel Lespinasse anon_vma_interval_tree_post_update_vma(vma); 199809357814SOleg Nesterov spin_unlock(&mm->page_table_lock); 19994128997bSMichel Lespinasse 20003af9e859SEric B Munson perf_event_mmap(vma); 20013af9e859SEric B Munson } 20021da177e4SLinus Torvalds } 200342c36f63SHugh Dickins } 200412352d3cSKonstantin Khlebnikov anon_vma_unlock_write(vma->anon_vma); 2005c791576cSYang Shi khugepaged_enter_vma(vma, vma->vm_flags); 2006d4af56c5SLiam R. Howlett mas_destroy(&mas); 20071da177e4SLinus Torvalds return error; 20081da177e4SLinus Torvalds } 200946dea3d0SHugh Dickins #endif /* CONFIG_STACK_GROWSUP || CONFIG_IA64 */ 201046dea3d0SHugh Dickins 20111da177e4SLinus Torvalds /* 20121da177e4SLinus Torvalds * vma is the first one with address < vma->vm_start. Have to extend vma. 20131da177e4SLinus Torvalds */ 2014524e00b3SLiam R. Howlett int expand_downwards(struct vm_area_struct *vma, unsigned long address) 20151da177e4SLinus Torvalds { 201609357814SOleg Nesterov struct mm_struct *mm = vma->vm_mm; 2017763ecb03SLiam R. Howlett MA_STATE(mas, &mm->mm_mt, vma->vm_start, vma->vm_start); 20181be7107fSHugh Dickins struct vm_area_struct *prev; 20190a1d5299SJann Horn int error = 0; 20201da177e4SLinus Torvalds 20218869477aSEric Paris address &= PAGE_MASK; 20220a1d5299SJann Horn if (address < mmap_min_addr) 20230a1d5299SJann Horn return -EPERM; 20248869477aSEric Paris 20251be7107fSHugh Dickins /* Enforce stack_guard_gap */ 2026763ecb03SLiam R. Howlett prev = mas_prev(&mas, 0); 20271be7107fSHugh Dickins /* Check that both stack segments have the same anon_vma? */ 202832e4e6d5SOleg Nesterov if (prev && !(prev->vm_flags & VM_GROWSDOWN) && 20293122e80eSAnshuman Khandual vma_is_accessible(prev)) { 203032e4e6d5SOleg Nesterov if (address - prev->vm_end < stack_guard_gap) 203132e4e6d5SOleg Nesterov return -ENOMEM; 20321be7107fSHugh Dickins } 20331be7107fSHugh Dickins 2034d4af56c5SLiam R. Howlett if (mas_preallocate(&mas, vma, GFP_KERNEL)) 203512352d3cSKonstantin Khlebnikov return -ENOMEM; 20361da177e4SLinus Torvalds 2037d4af56c5SLiam R. Howlett /* We must make sure the anon_vma is allocated. */ 2038d4af56c5SLiam R. Howlett if (unlikely(anon_vma_prepare(vma))) { 2039d4af56c5SLiam R. Howlett mas_destroy(&mas); 2040d4af56c5SLiam R. Howlett return -ENOMEM; 2041d4af56c5SLiam R. Howlett } 2042d4af56c5SLiam R. Howlett 20431da177e4SLinus Torvalds /* 20441da177e4SLinus Torvalds * vma->vm_start/vm_end cannot change under us because the caller 2045c1e8d7c6SMichel Lespinasse * is required to hold the mmap_lock in read mode. We need the 20461da177e4SLinus Torvalds * anon_vma lock to serialize against concurrent expand_stacks. 20471da177e4SLinus Torvalds */ 204812352d3cSKonstantin Khlebnikov anon_vma_lock_write(vma->anon_vma); 20491da177e4SLinus Torvalds 20501da177e4SLinus Torvalds /* Somebody else might have raced and expanded it already */ 20511da177e4SLinus Torvalds if (address < vma->vm_start) { 20521da177e4SLinus Torvalds unsigned long size, grow; 20531da177e4SLinus Torvalds 20541da177e4SLinus Torvalds size = vma->vm_end - address; 20551da177e4SLinus Torvalds grow = (vma->vm_start - address) >> PAGE_SHIFT; 20561da177e4SLinus Torvalds 2057a626ca6aSLinus Torvalds error = -ENOMEM; 2058a626ca6aSLinus Torvalds if (grow <= vma->vm_pgoff) { 20591da177e4SLinus Torvalds error = acct_stack_growth(vma, size, grow); 20601da177e4SLinus Torvalds if (!error) { 20614128997bSMichel Lespinasse /* 2062524e00b3SLiam R. Howlett * We only hold a shared mmap_lock lock here, so 2063524e00b3SLiam R. Howlett * we need to protect against concurrent vma 2064524e00b3SLiam R. Howlett * expansions. anon_vma_lock_write() doesn't 2065524e00b3SLiam R. Howlett * help here, as we don't guarantee that all 2066524e00b3SLiam R. Howlett * growable vmas in a mm share the same root 2067524e00b3SLiam R. Howlett * anon vma. So, we reuse mm->page_table_lock 2068524e00b3SLiam R. Howlett * to guard against concurrent vma expansions. 20694128997bSMichel Lespinasse */ 207009357814SOleg Nesterov spin_lock(&mm->page_table_lock); 207187e8827bSOleg Nesterov if (vma->vm_flags & VM_LOCKED) 207209357814SOleg Nesterov mm->locked_vm += grow; 207384638335SKonstantin Khlebnikov vm_stat_account(mm, vma->vm_flags, grow); 2074bf181b9fSMichel Lespinasse anon_vma_interval_tree_pre_update_vma(vma); 20751da177e4SLinus Torvalds vma->vm_start = address; 20761da177e4SLinus Torvalds vma->vm_pgoff -= grow; 2077d4af56c5SLiam R. Howlett /* Overwrite old entry in mtree. */ 2078d4af56c5SLiam R. Howlett vma_mas_store(vma, &mas); 2079bf181b9fSMichel Lespinasse anon_vma_interval_tree_post_update_vma(vma); 208009357814SOleg Nesterov spin_unlock(&mm->page_table_lock); 20814128997bSMichel Lespinasse 20823af9e859SEric B Munson perf_event_mmap(vma); 20831da177e4SLinus Torvalds } 20841da177e4SLinus Torvalds } 2085a626ca6aSLinus Torvalds } 208612352d3cSKonstantin Khlebnikov anon_vma_unlock_write(vma->anon_vma); 2087c791576cSYang Shi khugepaged_enter_vma(vma, vma->vm_flags); 2088d4af56c5SLiam R. Howlett mas_destroy(&mas); 20891da177e4SLinus Torvalds return error; 20901da177e4SLinus Torvalds } 20911da177e4SLinus Torvalds 20921be7107fSHugh Dickins /* enforced gap between the expanding stack and other mappings. */ 20931be7107fSHugh Dickins unsigned long stack_guard_gap = 256UL<<PAGE_SHIFT; 20941be7107fSHugh Dickins 20951be7107fSHugh Dickins static int __init cmdline_parse_stack_guard_gap(char *p) 20961be7107fSHugh Dickins { 20971be7107fSHugh Dickins unsigned long val; 20981be7107fSHugh Dickins char *endptr; 20991be7107fSHugh Dickins 21001be7107fSHugh Dickins val = simple_strtoul(p, &endptr, 10); 21011be7107fSHugh Dickins if (!*endptr) 21021be7107fSHugh Dickins stack_guard_gap = val << PAGE_SHIFT; 21031be7107fSHugh Dickins 2104e6d09493SRandy Dunlap return 1; 21051be7107fSHugh Dickins } 21061be7107fSHugh Dickins __setup("stack_guard_gap=", cmdline_parse_stack_guard_gap); 21071be7107fSHugh Dickins 2108b6a2fea3SOllie Wild #ifdef CONFIG_STACK_GROWSUP 2109b6a2fea3SOllie Wild int expand_stack(struct vm_area_struct *vma, unsigned long address) 2110b6a2fea3SOllie Wild { 2111b6a2fea3SOllie Wild return expand_upwards(vma, address); 2112b6a2fea3SOllie Wild } 2113b6a2fea3SOllie Wild 2114b6a2fea3SOllie Wild struct vm_area_struct * 2115b6a2fea3SOllie Wild find_extend_vma(struct mm_struct *mm, unsigned long addr) 2116b6a2fea3SOllie Wild { 2117b6a2fea3SOllie Wild struct vm_area_struct *vma, *prev; 2118b6a2fea3SOllie Wild 2119b6a2fea3SOllie Wild addr &= PAGE_MASK; 2120b6a2fea3SOllie Wild vma = find_vma_prev(mm, addr, &prev); 2121b6a2fea3SOllie Wild if (vma && (vma->vm_start <= addr)) 2122b6a2fea3SOllie Wild return vma; 21234d45e75aSJann Horn if (!prev || expand_stack(prev, addr)) 2124b6a2fea3SOllie Wild return NULL; 2125cea10a19SMichel Lespinasse if (prev->vm_flags & VM_LOCKED) 2126fc05f566SKirill A. Shutemov populate_vma_page_range(prev, addr, prev->vm_end, NULL); 2127b6a2fea3SOllie Wild return prev; 2128b6a2fea3SOllie Wild } 2129b6a2fea3SOllie Wild #else 2130b6a2fea3SOllie Wild int expand_stack(struct vm_area_struct *vma, unsigned long address) 2131b6a2fea3SOllie Wild { 2132b6a2fea3SOllie Wild return expand_downwards(vma, address); 2133b6a2fea3SOllie Wild } 2134b6a2fea3SOllie Wild 21351da177e4SLinus Torvalds struct vm_area_struct * 21361da177e4SLinus Torvalds find_extend_vma(struct mm_struct *mm, unsigned long addr) 21371da177e4SLinus Torvalds { 21381da177e4SLinus Torvalds struct vm_area_struct *vma; 21391da177e4SLinus Torvalds unsigned long start; 21401da177e4SLinus Torvalds 21411da177e4SLinus Torvalds addr &= PAGE_MASK; 21421da177e4SLinus Torvalds vma = find_vma(mm, addr); 21431da177e4SLinus Torvalds if (!vma) 21441da177e4SLinus Torvalds return NULL; 21451da177e4SLinus Torvalds if (vma->vm_start <= addr) 21461da177e4SLinus Torvalds return vma; 21471da177e4SLinus Torvalds if (!(vma->vm_flags & VM_GROWSDOWN)) 21481da177e4SLinus Torvalds return NULL; 21491da177e4SLinus Torvalds start = vma->vm_start; 21501da177e4SLinus Torvalds if (expand_stack(vma, addr)) 21511da177e4SLinus Torvalds return NULL; 2152cea10a19SMichel Lespinasse if (vma->vm_flags & VM_LOCKED) 2153fc05f566SKirill A. Shutemov populate_vma_page_range(vma, addr, start, NULL); 21541da177e4SLinus Torvalds return vma; 21551da177e4SLinus Torvalds } 21561da177e4SLinus Torvalds #endif 21571da177e4SLinus Torvalds 2158e1d6d01aSJesse Barnes EXPORT_SYMBOL_GPL(find_extend_vma); 2159e1d6d01aSJesse Barnes 21602c0b3814SHugh Dickins /* 2161763ecb03SLiam R. Howlett * Ok - we have the memory areas we should free on a maple tree so release them, 2162763ecb03SLiam R. Howlett * and do the vma updates. 21631da177e4SLinus Torvalds * 21642c0b3814SHugh Dickins * Called with the mm semaphore held. 21651da177e4SLinus Torvalds */ 2166763ecb03SLiam R. Howlett static inline void remove_mt(struct mm_struct *mm, struct ma_state *mas) 21671da177e4SLinus Torvalds { 21684f74d2c8SLinus Torvalds unsigned long nr_accounted = 0; 2169763ecb03SLiam R. Howlett struct vm_area_struct *vma; 21704f74d2c8SLinus Torvalds 2171365e9c87SHugh Dickins /* Update high watermark before we lower total_vm */ 2172365e9c87SHugh Dickins update_hiwater_vm(mm); 2173763ecb03SLiam R. Howlett mas_for_each(mas, vma, ULONG_MAX) { 2174ab50b8edSHugh Dickins long nrpages = vma_pages(vma); 21751da177e4SLinus Torvalds 21764f74d2c8SLinus Torvalds if (vma->vm_flags & VM_ACCOUNT) 21774f74d2c8SLinus Torvalds nr_accounted += nrpages; 217884638335SKonstantin Khlebnikov vm_stat_account(mm, vma->vm_flags, -nrpages); 2179763ecb03SLiam R. Howlett remove_vma(vma); 2180763ecb03SLiam R. Howlett } 21814f74d2c8SLinus Torvalds vm_unacct_memory(nr_accounted); 21821da177e4SLinus Torvalds validate_mm(mm); 21831da177e4SLinus Torvalds } 21841da177e4SLinus Torvalds 21851da177e4SLinus Torvalds /* 21861da177e4SLinus Torvalds * Get rid of page table information in the indicated region. 21871da177e4SLinus Torvalds * 2188f10df686SPaolo 'Blaisorblade' Giarrusso * Called with the mm semaphore held. 21891da177e4SLinus Torvalds */ 2190763ecb03SLiam R. Howlett static void unmap_region(struct mm_struct *mm, struct maple_tree *mt, 2191e0da382cSHugh Dickins struct vm_area_struct *vma, struct vm_area_struct *prev, 2192763ecb03SLiam R. Howlett struct vm_area_struct *next, 2193e0da382cSHugh Dickins unsigned long start, unsigned long end) 21941da177e4SLinus Torvalds { 2195d16dfc55SPeter Zijlstra struct mmu_gather tlb; 21961da177e4SLinus Torvalds 21971da177e4SLinus Torvalds lru_add_drain(); 2198a72afd87SWill Deacon tlb_gather_mmu(&tlb, mm); 2199365e9c87SHugh Dickins update_hiwater_rss(mm); 2200763ecb03SLiam R. Howlett unmap_vmas(&tlb, mt, vma, start, end); 2201763ecb03SLiam R. Howlett free_pgtables(&tlb, mt, vma, prev ? prev->vm_end : FIRST_USER_ADDRESS, 22026ee8630eSHugh Dickins next ? next->vm_start : USER_PGTABLES_CEILING); 2203ae8eba8bSWill Deacon tlb_finish_mmu(&tlb); 22041da177e4SLinus Torvalds } 22051da177e4SLinus Torvalds 22061da177e4SLinus Torvalds /* 2207def5efe0SDavid Rientjes * __split_vma() bypasses sysctl_max_map_count checking. We use this where it 2208def5efe0SDavid Rientjes * has already been checked or doesn't make sense to fail. 22091da177e4SLinus Torvalds */ 2210def5efe0SDavid Rientjes int __split_vma(struct mm_struct *mm, struct vm_area_struct *vma, 22111da177e4SLinus Torvalds unsigned long addr, int new_below) 22121da177e4SLinus Torvalds { 22131da177e4SLinus Torvalds struct vm_area_struct *new; 2214e3975891SChen Gang int err; 2215d4af56c5SLiam R. Howlett validate_mm_mt(mm); 22161da177e4SLinus Torvalds 2217dd3b614fSDmitry Safonov if (vma->vm_ops && vma->vm_ops->may_split) { 2218dd3b614fSDmitry Safonov err = vma->vm_ops->may_split(vma, addr); 221931383c68SDan Williams if (err) 222031383c68SDan Williams return err; 222131383c68SDan Williams } 22221da177e4SLinus Torvalds 22233928d4f5SLinus Torvalds new = vm_area_dup(vma); 22241da177e4SLinus Torvalds if (!new) 2225e3975891SChen Gang return -ENOMEM; 22261da177e4SLinus Torvalds 22271da177e4SLinus Torvalds if (new_below) 22281da177e4SLinus Torvalds new->vm_end = addr; 22291da177e4SLinus Torvalds else { 22301da177e4SLinus Torvalds new->vm_start = addr; 22311da177e4SLinus Torvalds new->vm_pgoff += ((addr - vma->vm_start) >> PAGE_SHIFT); 22321da177e4SLinus Torvalds } 22331da177e4SLinus Torvalds 2234ef0855d3SOleg Nesterov err = vma_dup_policy(vma, new); 2235ef0855d3SOleg Nesterov if (err) 22365beb4930SRik van Riel goto out_free_vma; 22371da177e4SLinus Torvalds 2238c4ea95d7SDaniel Forrest err = anon_vma_clone(new, vma); 2239c4ea95d7SDaniel Forrest if (err) 22405beb4930SRik van Riel goto out_free_mpol; 22415beb4930SRik van Riel 2242e9714acfSKonstantin Khlebnikov if (new->vm_file) 22431da177e4SLinus Torvalds get_file(new->vm_file); 22441da177e4SLinus Torvalds 22451da177e4SLinus Torvalds if (new->vm_ops && new->vm_ops->open) 22461da177e4SLinus Torvalds new->vm_ops->open(new); 22471da177e4SLinus Torvalds 22481da177e4SLinus Torvalds if (new_below) 22495beb4930SRik van Riel err = vma_adjust(vma, addr, vma->vm_end, vma->vm_pgoff + 22501da177e4SLinus Torvalds ((addr - new->vm_start) >> PAGE_SHIFT), new); 22511da177e4SLinus Torvalds else 22525beb4930SRik van Riel err = vma_adjust(vma, vma->vm_start, addr, vma->vm_pgoff, new); 22531da177e4SLinus Torvalds 22545beb4930SRik van Riel /* Success. */ 22555beb4930SRik van Riel if (!err) 22561da177e4SLinus Torvalds return 0; 22575beb4930SRik van Riel 2258d4af56c5SLiam R. Howlett /* Avoid vm accounting in close() operation */ 2259d4af56c5SLiam R. Howlett new->vm_start = new->vm_end; 2260d4af56c5SLiam R. Howlett new->vm_pgoff = 0; 22615beb4930SRik van Riel /* Clean everything up if vma_adjust failed. */ 226258927533SRik van Riel if (new->vm_ops && new->vm_ops->close) 22635beb4930SRik van Riel new->vm_ops->close(new); 2264e9714acfSKonstantin Khlebnikov if (new->vm_file) 22655beb4930SRik van Riel fput(new->vm_file); 22662aeadc30SAndrea Arcangeli unlink_anon_vmas(new); 22675beb4930SRik van Riel out_free_mpol: 2268ef0855d3SOleg Nesterov mpol_put(vma_policy(new)); 22695beb4930SRik van Riel out_free_vma: 22703928d4f5SLinus Torvalds vm_area_free(new); 2271d4af56c5SLiam R. Howlett validate_mm_mt(mm); 22725beb4930SRik van Riel return err; 22731da177e4SLinus Torvalds } 22741da177e4SLinus Torvalds 2275659ace58SKOSAKI Motohiro /* 2276659ace58SKOSAKI Motohiro * Split a vma into two pieces at address 'addr', a new vma is allocated 2277659ace58SKOSAKI Motohiro * either for the first part or the tail. 2278659ace58SKOSAKI Motohiro */ 2279659ace58SKOSAKI Motohiro int split_vma(struct mm_struct *mm, struct vm_area_struct *vma, 2280659ace58SKOSAKI Motohiro unsigned long addr, int new_below) 2281659ace58SKOSAKI Motohiro { 2282659ace58SKOSAKI Motohiro if (mm->map_count >= sysctl_max_map_count) 2283659ace58SKOSAKI Motohiro return -ENOMEM; 2284659ace58SKOSAKI Motohiro 2285659ace58SKOSAKI Motohiro return __split_vma(mm, vma, addr, new_below); 2286659ace58SKOSAKI Motohiro } 2287659ace58SKOSAKI Motohiro 2288763ecb03SLiam R. Howlett static inline int munmap_sidetree(struct vm_area_struct *vma, 2289763ecb03SLiam R. Howlett struct ma_state *mas_detach) 22901da177e4SLinus Torvalds { 2291763ecb03SLiam R. Howlett mas_set_range(mas_detach, vma->vm_start, vma->vm_end - 1); 2292763ecb03SLiam R. Howlett if (mas_store_gfp(mas_detach, vma, GFP_KERNEL)) 2293763ecb03SLiam R. Howlett return -ENOMEM; 229411f9a21aSLiam R. Howlett 2295763ecb03SLiam R. Howlett if (vma->vm_flags & VM_LOCKED) 2296763ecb03SLiam R. Howlett vma->vm_mm->locked_vm -= vma_pages(vma); 229711f9a21aSLiam R. Howlett 2298763ecb03SLiam R. Howlett return 0; 229911f9a21aSLiam R. Howlett } 230011f9a21aSLiam R. Howlett 230111f9a21aSLiam R. Howlett /* 230211f9a21aSLiam R. Howlett * do_mas_align_munmap() - munmap the aligned region from @start to @end. 230311f9a21aSLiam R. Howlett * @mas: The maple_state, ideally set up to alter the correct tree location. 230411f9a21aSLiam R. Howlett * @vma: The starting vm_area_struct 230511f9a21aSLiam R. Howlett * @mm: The mm_struct 230611f9a21aSLiam R. Howlett * @start: The aligned start address to munmap. 230711f9a21aSLiam R. Howlett * @end: The aligned end address to munmap. 230811f9a21aSLiam R. Howlett * @uf: The userfaultfd list_head 230911f9a21aSLiam R. Howlett * @downgrade: Set to true to attempt a write downgrade of the mmap_sem 231011f9a21aSLiam R. Howlett * 231111f9a21aSLiam R. Howlett * If @downgrade is true, check return code for potential release of the lock. 231211f9a21aSLiam R. Howlett */ 231311f9a21aSLiam R. Howlett static int 231411f9a21aSLiam R. Howlett do_mas_align_munmap(struct ma_state *mas, struct vm_area_struct *vma, 231511f9a21aSLiam R. Howlett struct mm_struct *mm, unsigned long start, 231611f9a21aSLiam R. Howlett unsigned long end, struct list_head *uf, bool downgrade) 231711f9a21aSLiam R. Howlett { 2318763ecb03SLiam R. Howlett struct vm_area_struct *prev, *next = NULL; 2319763ecb03SLiam R. Howlett struct maple_tree mt_detach; 2320763ecb03SLiam R. Howlett int count = 0; 2321d4af56c5SLiam R. Howlett int error = -ENOMEM; 2322763ecb03SLiam R. Howlett MA_STATE(mas_detach, &mt_detach, 0, 0); 2323763ecb03SLiam R. Howlett mt_init_flags(&mt_detach, MT_FLAGS_LOCK_EXTERN); 2324763ecb03SLiam R. Howlett mt_set_external_lock(&mt_detach, &mm->mmap_lock); 2325524e00b3SLiam R. Howlett 232611f9a21aSLiam R. Howlett if (mas_preallocate(mas, vma, GFP_KERNEL)) 232711f9a21aSLiam R. Howlett return -ENOMEM; 232811f9a21aSLiam R. Howlett 232911f9a21aSLiam R. Howlett mas->last = end - 1; 23301da177e4SLinus Torvalds /* 23311da177e4SLinus Torvalds * If we need to split any vma, do it now to save pain later. 23321da177e4SLinus Torvalds * 23331da177e4SLinus Torvalds * Note: mremap's move_vma VM_ACCOUNT handling assumes a partially 23341da177e4SLinus Torvalds * unmapped vm_area_struct will remain in use: so lower split_vma 23351da177e4SLinus Torvalds * places tmp vma above, and higher split_vma places tmp vma below. 23361da177e4SLinus Torvalds */ 2337763ecb03SLiam R. Howlett 2338763ecb03SLiam R. Howlett /* Does it split the first one? */ 2339146425a3SHugh Dickins if (start > vma->vm_start) { 2340659ace58SKOSAKI Motohiro 2341659ace58SKOSAKI Motohiro /* 2342659ace58SKOSAKI Motohiro * Make sure that map_count on return from munmap() will 2343659ace58SKOSAKI Motohiro * not exceed its limit; but let map_count go just above 2344659ace58SKOSAKI Motohiro * its limit temporarily, to help free resources as expected. 2345659ace58SKOSAKI Motohiro */ 2346659ace58SKOSAKI Motohiro if (end < vma->vm_end && mm->map_count >= sysctl_max_map_count) 2347d4af56c5SLiam R. Howlett goto map_count_exceeded; 2348659ace58SKOSAKI Motohiro 2349763ecb03SLiam R. Howlett /* 2350763ecb03SLiam R. Howlett * mas_pause() is not needed since mas->index needs to be set 2351763ecb03SLiam R. Howlett * differently than vma->vm_end anyways. 2352763ecb03SLiam R. Howlett */ 2353659ace58SKOSAKI Motohiro error = __split_vma(mm, vma, start, 0); 23541da177e4SLinus Torvalds if (error) 2355763ecb03SLiam R. Howlett goto start_split_failed; 235611f9a21aSLiam R. Howlett 2357763ecb03SLiam R. Howlett mas_set(mas, start); 2358763ecb03SLiam R. Howlett vma = mas_walk(mas); 23591da177e4SLinus Torvalds } 23601da177e4SLinus Torvalds 2361763ecb03SLiam R. Howlett prev = mas_prev(mas, 0); 2362763ecb03SLiam R. Howlett if (unlikely((!prev))) 2363763ecb03SLiam R. Howlett mas_set(mas, start); 236411f9a21aSLiam R. Howlett 2365763ecb03SLiam R. Howlett /* 2366763ecb03SLiam R. Howlett * Detach a range of VMAs from the mm. Using next as a temp variable as 2367763ecb03SLiam R. Howlett * it is always overwritten. 2368763ecb03SLiam R. Howlett */ 2369763ecb03SLiam R. Howlett mas_for_each(mas, next, end - 1) { 2370763ecb03SLiam R. Howlett /* Does it split the end? */ 2371763ecb03SLiam R. Howlett if (next->vm_end > end) { 2372763ecb03SLiam R. Howlett struct vm_area_struct *split; 237311f9a21aSLiam R. Howlett 2374763ecb03SLiam R. Howlett error = __split_vma(mm, next, end, 1); 23751da177e4SLinus Torvalds if (error) 2376763ecb03SLiam R. Howlett goto end_split_failed; 237711f9a21aSLiam R. Howlett 2378763ecb03SLiam R. Howlett mas_set(mas, end); 2379763ecb03SLiam R. Howlett split = mas_prev(mas, 0); 2380763ecb03SLiam R. Howlett error = munmap_sidetree(split, &mas_detach); 2381763ecb03SLiam R. Howlett if (error) 2382763ecb03SLiam R. Howlett goto munmap_sidetree_failed; 2383763ecb03SLiam R. Howlett 2384763ecb03SLiam R. Howlett count++; 2385763ecb03SLiam R. Howlett if (vma == next) 2386763ecb03SLiam R. Howlett vma = split; 2387763ecb03SLiam R. Howlett break; 238811f9a21aSLiam R. Howlett } 2389763ecb03SLiam R. Howlett error = munmap_sidetree(next, &mas_detach); 2390763ecb03SLiam R. Howlett if (error) 2391763ecb03SLiam R. Howlett goto munmap_sidetree_failed; 2392763ecb03SLiam R. Howlett 2393763ecb03SLiam R. Howlett count++; 2394763ecb03SLiam R. Howlett #ifdef CONFIG_DEBUG_VM_MAPLE_TREE 2395763ecb03SLiam R. Howlett BUG_ON(next->vm_start < start); 2396763ecb03SLiam R. Howlett BUG_ON(next->vm_start > end); 2397763ecb03SLiam R. Howlett #endif 2398763ecb03SLiam R. Howlett } 2399763ecb03SLiam R. Howlett 2400763ecb03SLiam R. Howlett if (!next) 2401763ecb03SLiam R. Howlett next = mas_next(mas, ULONG_MAX); 24021da177e4SLinus Torvalds 24032376dd7cSAndrea Arcangeli if (unlikely(uf)) { 24042376dd7cSAndrea Arcangeli /* 24052376dd7cSAndrea Arcangeli * If userfaultfd_unmap_prep returns an error the vmas 2406f0953a1bSIngo Molnar * will remain split, but userland will get a 24072376dd7cSAndrea Arcangeli * highly unexpected error anyway. This is no 24082376dd7cSAndrea Arcangeli * different than the case where the first of the two 24092376dd7cSAndrea Arcangeli * __split_vma fails, but we don't undo the first 24102376dd7cSAndrea Arcangeli * split, despite we could. This is unlikely enough 24112376dd7cSAndrea Arcangeli * failure that it's not worth optimizing it for. 24122376dd7cSAndrea Arcangeli */ 241369dbe6daSLiam R. Howlett error = userfaultfd_unmap_prep(mm, start, end, uf); 241411f9a21aSLiam R. Howlett 24152376dd7cSAndrea Arcangeli if (error) 2416d4af56c5SLiam R. Howlett goto userfaultfd_error; 24172376dd7cSAndrea Arcangeli } 24182376dd7cSAndrea Arcangeli 2419763ecb03SLiam R. Howlett /* Point of no return */ 2420763ecb03SLiam R. Howlett mas_set_range(mas, start, end - 1); 2421763ecb03SLiam R. Howlett #if defined(CONFIG_DEBUG_VM_MAPLE_TREE) 2422763ecb03SLiam R. Howlett /* Make sure no VMAs are about to be lost. */ 2423763ecb03SLiam R. Howlett { 2424763ecb03SLiam R. Howlett MA_STATE(test, &mt_detach, start, end - 1); 2425763ecb03SLiam R. Howlett struct vm_area_struct *vma_mas, *vma_test; 2426763ecb03SLiam R. Howlett int test_count = 0; 2427763ecb03SLiam R. Howlett 2428763ecb03SLiam R. Howlett rcu_read_lock(); 2429763ecb03SLiam R. Howlett vma_test = mas_find(&test, end - 1); 2430763ecb03SLiam R. Howlett mas_for_each(mas, vma_mas, end - 1) { 2431763ecb03SLiam R. Howlett BUG_ON(vma_mas != vma_test); 2432763ecb03SLiam R. Howlett test_count++; 2433763ecb03SLiam R. Howlett vma_test = mas_next(&test, end - 1); 2434763ecb03SLiam R. Howlett } 2435763ecb03SLiam R. Howlett rcu_read_unlock(); 2436763ecb03SLiam R. Howlett BUG_ON(count != test_count); 2437763ecb03SLiam R. Howlett mas_set_range(mas, start, end - 1); 2438763ecb03SLiam R. Howlett } 2439763ecb03SLiam R. Howlett #endif 244011f9a21aSLiam R. Howlett mas_store_prealloc(mas, NULL); 2441763ecb03SLiam R. Howlett mm->map_count -= count; 244211f9a21aSLiam R. Howlett /* 244311f9a21aSLiam R. Howlett * Do not downgrade mmap_lock if we are next to VM_GROWSDOWN or 244411f9a21aSLiam R. Howlett * VM_GROWSUP VMA. Such VMAs can change their size under 244511f9a21aSLiam R. Howlett * down_read(mmap_lock) and collide with the VMA we are about to unmap. 244611f9a21aSLiam R. Howlett */ 244711f9a21aSLiam R. Howlett if (downgrade) { 2448763ecb03SLiam R. Howlett if (next && (next->vm_flags & VM_GROWSDOWN)) 244911f9a21aSLiam R. Howlett downgrade = false; 245011f9a21aSLiam R. Howlett else if (prev && (prev->vm_flags & VM_GROWSUP)) 245111f9a21aSLiam R. Howlett downgrade = false; 245211f9a21aSLiam R. Howlett else 2453d8ed45c5SMichel Lespinasse mmap_write_downgrade(mm); 245411f9a21aSLiam R. Howlett } 2455dd2283f2SYang Shi 2456763ecb03SLiam R. Howlett unmap_region(mm, &mt_detach, vma, prev, next, start, end); 2457763ecb03SLiam R. Howlett /* Statistics and freeing VMAs */ 2458763ecb03SLiam R. Howlett mas_set(&mas_detach, start); 2459763ecb03SLiam R. Howlett remove_mt(mm, &mas_detach); 2460763ecb03SLiam R. Howlett __mt_destroy(&mt_detach); 24611da177e4SLinus Torvalds 2462524e00b3SLiam R. Howlett 2463524e00b3SLiam R. Howlett validate_mm(mm); 2464dd2283f2SYang Shi return downgrade ? 1 : 0; 2465d4af56c5SLiam R. Howlett 2466d4af56c5SLiam R. Howlett userfaultfd_error: 2467763ecb03SLiam R. Howlett munmap_sidetree_failed: 2468763ecb03SLiam R. Howlett end_split_failed: 2469763ecb03SLiam R. Howlett __mt_destroy(&mt_detach); 2470763ecb03SLiam R. Howlett start_split_failed: 2471763ecb03SLiam R. Howlett map_count_exceeded: 247211f9a21aSLiam R. Howlett mas_destroy(mas); 2473d4af56c5SLiam R. Howlett return error; 24741da177e4SLinus Torvalds } 24751da177e4SLinus Torvalds 247611f9a21aSLiam R. Howlett /* 247711f9a21aSLiam R. Howlett * do_mas_munmap() - munmap a given range. 247811f9a21aSLiam R. Howlett * @mas: The maple state 247911f9a21aSLiam R. Howlett * @mm: The mm_struct 248011f9a21aSLiam R. Howlett * @start: The start address to munmap 248111f9a21aSLiam R. Howlett * @len: The length of the range to munmap 248211f9a21aSLiam R. Howlett * @uf: The userfaultfd list_head 248311f9a21aSLiam R. Howlett * @downgrade: set to true if the user wants to attempt to write_downgrade the 248411f9a21aSLiam R. Howlett * mmap_sem 248511f9a21aSLiam R. Howlett * 248611f9a21aSLiam R. Howlett * This function takes a @mas that is either pointing to the previous VMA or set 248711f9a21aSLiam R. Howlett * to MA_START and sets it up to remove the mapping(s). The @len will be 248811f9a21aSLiam R. Howlett * aligned and any arch_unmap work will be preformed. 248911f9a21aSLiam R. Howlett * 249011f9a21aSLiam R. Howlett * Returns: -EINVAL on failure, 1 on success and unlock, 0 otherwise. 249111f9a21aSLiam R. Howlett */ 249211f9a21aSLiam R. Howlett int do_mas_munmap(struct ma_state *mas, struct mm_struct *mm, 249311f9a21aSLiam R. Howlett unsigned long start, size_t len, struct list_head *uf, 249411f9a21aSLiam R. Howlett bool downgrade) 249511f9a21aSLiam R. Howlett { 249611f9a21aSLiam R. Howlett unsigned long end; 249711f9a21aSLiam R. Howlett struct vm_area_struct *vma; 249811f9a21aSLiam R. Howlett 249911f9a21aSLiam R. Howlett if ((offset_in_page(start)) || start > TASK_SIZE || len > TASK_SIZE-start) 250011f9a21aSLiam R. Howlett return -EINVAL; 250111f9a21aSLiam R. Howlett 250211f9a21aSLiam R. Howlett end = start + PAGE_ALIGN(len); 250311f9a21aSLiam R. Howlett if (end == start) 250411f9a21aSLiam R. Howlett return -EINVAL; 250511f9a21aSLiam R. Howlett 250611f9a21aSLiam R. Howlett /* arch_unmap() might do unmaps itself. */ 250711f9a21aSLiam R. Howlett arch_unmap(mm, start, end); 250811f9a21aSLiam R. Howlett 250911f9a21aSLiam R. Howlett /* Find the first overlapping VMA */ 251011f9a21aSLiam R. Howlett vma = mas_find(mas, end - 1); 251111f9a21aSLiam R. Howlett if (!vma) 251211f9a21aSLiam R. Howlett return 0; 251311f9a21aSLiam R. Howlett 251411f9a21aSLiam R. Howlett return do_mas_align_munmap(mas, vma, mm, start, end, uf, downgrade); 251511f9a21aSLiam R. Howlett } 251611f9a21aSLiam R. Howlett 251711f9a21aSLiam R. Howlett /* do_munmap() - Wrapper function for non-maple tree aware do_munmap() calls. 251811f9a21aSLiam R. Howlett * @mm: The mm_struct 251911f9a21aSLiam R. Howlett * @start: The start address to munmap 252011f9a21aSLiam R. Howlett * @len: The length to be munmapped. 252111f9a21aSLiam R. Howlett * @uf: The userfaultfd list_head 252211f9a21aSLiam R. Howlett */ 2523dd2283f2SYang Shi int do_munmap(struct mm_struct *mm, unsigned long start, size_t len, 2524dd2283f2SYang Shi struct list_head *uf) 2525dd2283f2SYang Shi { 252611f9a21aSLiam R. Howlett MA_STATE(mas, &mm->mm_mt, start, start); 252711f9a21aSLiam R. Howlett 252811f9a21aSLiam R. Howlett return do_mas_munmap(&mas, mm, start, len, uf, false); 2529dd2283f2SYang Shi } 2530dd2283f2SYang Shi 2531e99668a5SLiam R. Howlett unsigned long mmap_region(struct file *file, unsigned long addr, 2532e99668a5SLiam R. Howlett unsigned long len, vm_flags_t vm_flags, unsigned long pgoff, 2533e99668a5SLiam R. Howlett struct list_head *uf) 2534e99668a5SLiam R. Howlett { 2535e99668a5SLiam R. Howlett struct mm_struct *mm = current->mm; 2536e99668a5SLiam R. Howlett struct vm_area_struct *vma = NULL; 2537e99668a5SLiam R. Howlett struct vm_area_struct *next, *prev, *merge; 2538e99668a5SLiam R. Howlett pgoff_t pglen = len >> PAGE_SHIFT; 2539e99668a5SLiam R. Howlett unsigned long charged = 0; 2540e99668a5SLiam R. Howlett unsigned long end = addr + len; 2541e99668a5SLiam R. Howlett unsigned long merge_start = addr, merge_end = end; 2542e99668a5SLiam R. Howlett pgoff_t vm_pgoff; 2543e99668a5SLiam R. Howlett int error; 2544e99668a5SLiam R. Howlett MA_STATE(mas, &mm->mm_mt, addr, end - 1); 2545e99668a5SLiam R. Howlett 2546e99668a5SLiam R. Howlett /* Check against address space limit. */ 2547e99668a5SLiam R. Howlett if (!may_expand_vm(mm, vm_flags, len >> PAGE_SHIFT)) { 2548e99668a5SLiam R. Howlett unsigned long nr_pages; 2549e99668a5SLiam R. Howlett 2550e99668a5SLiam R. Howlett /* 2551e99668a5SLiam R. Howlett * MAP_FIXED may remove pages of mappings that intersects with 2552e99668a5SLiam R. Howlett * requested mapping. Account for the pages it would unmap. 2553e99668a5SLiam R. Howlett */ 2554e99668a5SLiam R. Howlett nr_pages = count_vma_pages_range(mm, addr, end); 2555e99668a5SLiam R. Howlett 2556e99668a5SLiam R. Howlett if (!may_expand_vm(mm, vm_flags, 2557e99668a5SLiam R. Howlett (len >> PAGE_SHIFT) - nr_pages)) 2558e99668a5SLiam R. Howlett return -ENOMEM; 2559e99668a5SLiam R. Howlett } 2560e99668a5SLiam R. Howlett 2561e99668a5SLiam R. Howlett /* Unmap any existing mapping in the area */ 256211f9a21aSLiam R. Howlett if (do_mas_munmap(&mas, mm, addr, len, uf, false)) 2563e99668a5SLiam R. Howlett return -ENOMEM; 2564e99668a5SLiam R. Howlett 2565e99668a5SLiam R. Howlett /* 2566e99668a5SLiam R. Howlett * Private writable mapping: check memory availability 2567e99668a5SLiam R. Howlett */ 2568e99668a5SLiam R. Howlett if (accountable_mapping(file, vm_flags)) { 2569e99668a5SLiam R. Howlett charged = len >> PAGE_SHIFT; 2570e99668a5SLiam R. Howlett if (security_vm_enough_memory_mm(mm, charged)) 2571e99668a5SLiam R. Howlett return -ENOMEM; 2572e99668a5SLiam R. Howlett vm_flags |= VM_ACCOUNT; 2573e99668a5SLiam R. Howlett } 2574e99668a5SLiam R. Howlett 2575e99668a5SLiam R. Howlett next = mas_next(&mas, ULONG_MAX); 2576e99668a5SLiam R. Howlett prev = mas_prev(&mas, 0); 2577e99668a5SLiam R. Howlett if (vm_flags & VM_SPECIAL) 2578e99668a5SLiam R. Howlett goto cannot_expand; 2579e99668a5SLiam R. Howlett 2580e99668a5SLiam R. Howlett /* Attempt to expand an old mapping */ 2581e99668a5SLiam R. Howlett /* Check next */ 2582e99668a5SLiam R. Howlett if (next && next->vm_start == end && !vma_policy(next) && 2583e99668a5SLiam R. Howlett can_vma_merge_before(next, vm_flags, NULL, file, pgoff+pglen, 2584e99668a5SLiam R. Howlett NULL_VM_UFFD_CTX, NULL)) { 2585e99668a5SLiam R. Howlett merge_end = next->vm_end; 2586e99668a5SLiam R. Howlett vma = next; 2587e99668a5SLiam R. Howlett vm_pgoff = next->vm_pgoff - pglen; 2588e99668a5SLiam R. Howlett } 2589e99668a5SLiam R. Howlett 2590e99668a5SLiam R. Howlett /* Check prev */ 2591e99668a5SLiam R. Howlett if (prev && prev->vm_end == addr && !vma_policy(prev) && 2592e99668a5SLiam R. Howlett (vma ? can_vma_merge_after(prev, vm_flags, vma->anon_vma, file, 2593e99668a5SLiam R. Howlett pgoff, vma->vm_userfaultfd_ctx, NULL) : 2594e99668a5SLiam R. Howlett can_vma_merge_after(prev, vm_flags, NULL, file, pgoff, 2595e99668a5SLiam R. Howlett NULL_VM_UFFD_CTX, NULL))) { 2596e99668a5SLiam R. Howlett merge_start = prev->vm_start; 2597e99668a5SLiam R. Howlett vma = prev; 2598e99668a5SLiam R. Howlett vm_pgoff = prev->vm_pgoff; 2599e99668a5SLiam R. Howlett } 2600e99668a5SLiam R. Howlett 2601e99668a5SLiam R. Howlett 2602e99668a5SLiam R. Howlett /* Actually expand, if possible */ 2603e99668a5SLiam R. Howlett if (vma && 2604e99668a5SLiam R. Howlett !vma_expand(&mas, vma, merge_start, merge_end, vm_pgoff, next)) { 2605e99668a5SLiam R. Howlett khugepaged_enter_vma(vma, vm_flags); 2606e99668a5SLiam R. Howlett goto expanded; 2607e99668a5SLiam R. Howlett } 2608e99668a5SLiam R. Howlett 2609e99668a5SLiam R. Howlett mas.index = addr; 2610e99668a5SLiam R. Howlett mas.last = end - 1; 2611e99668a5SLiam R. Howlett cannot_expand: 2612e99668a5SLiam R. Howlett /* 2613e99668a5SLiam R. Howlett * Determine the object being mapped and call the appropriate 2614e99668a5SLiam R. Howlett * specific mapper. the address has already been validated, but 2615e99668a5SLiam R. Howlett * not unmapped, but the maps are removed from the list. 2616e99668a5SLiam R. Howlett */ 2617e99668a5SLiam R. Howlett vma = vm_area_alloc(mm); 2618e99668a5SLiam R. Howlett if (!vma) { 2619e99668a5SLiam R. Howlett error = -ENOMEM; 2620e99668a5SLiam R. Howlett goto unacct_error; 2621e99668a5SLiam R. Howlett } 2622e99668a5SLiam R. Howlett 2623e99668a5SLiam R. Howlett vma->vm_start = addr; 2624e99668a5SLiam R. Howlett vma->vm_end = end; 2625e99668a5SLiam R. Howlett vma->vm_flags = vm_flags; 2626e99668a5SLiam R. Howlett vma->vm_page_prot = vm_get_page_prot(vm_flags); 2627e99668a5SLiam R. Howlett vma->vm_pgoff = pgoff; 2628e99668a5SLiam R. Howlett 2629e99668a5SLiam R. Howlett if (file) { 2630e99668a5SLiam R. Howlett if (vm_flags & VM_SHARED) { 2631e99668a5SLiam R. Howlett error = mapping_map_writable(file->f_mapping); 2632e99668a5SLiam R. Howlett if (error) 2633e99668a5SLiam R. Howlett goto free_vma; 2634e99668a5SLiam R. Howlett } 2635e99668a5SLiam R. Howlett 2636e99668a5SLiam R. Howlett vma->vm_file = get_file(file); 2637e99668a5SLiam R. Howlett error = call_mmap(file, vma); 2638e99668a5SLiam R. Howlett if (error) 2639e99668a5SLiam R. Howlett goto unmap_and_free_vma; 2640e99668a5SLiam R. Howlett 2641e99668a5SLiam R. Howlett /* Can addr have changed?? 2642e99668a5SLiam R. Howlett * 2643e99668a5SLiam R. Howlett * Answer: Yes, several device drivers can do it in their 2644e99668a5SLiam R. Howlett * f_op->mmap method. -DaveM 2645e99668a5SLiam R. Howlett */ 2646e99668a5SLiam R. Howlett WARN_ON_ONCE(addr != vma->vm_start); 2647e99668a5SLiam R. Howlett 2648e99668a5SLiam R. Howlett addr = vma->vm_start; 2649e99668a5SLiam R. Howlett mas_reset(&mas); 2650e99668a5SLiam R. Howlett 2651e99668a5SLiam R. Howlett /* 2652e99668a5SLiam R. Howlett * If vm_flags changed after call_mmap(), we should try merge 2653e99668a5SLiam R. Howlett * vma again as we may succeed this time. 2654e99668a5SLiam R. Howlett */ 2655e99668a5SLiam R. Howlett if (unlikely(vm_flags != vma->vm_flags && prev)) { 2656e99668a5SLiam R. Howlett merge = vma_merge(mm, prev, vma->vm_start, vma->vm_end, vma->vm_flags, 2657e99668a5SLiam R. Howlett NULL, vma->vm_file, vma->vm_pgoff, NULL, NULL_VM_UFFD_CTX, NULL); 2658e99668a5SLiam R. Howlett if (merge) { 2659e99668a5SLiam R. Howlett /* 2660e99668a5SLiam R. Howlett * ->mmap() can change vma->vm_file and fput 2661e99668a5SLiam R. Howlett * the original file. So fput the vma->vm_file 2662e99668a5SLiam R. Howlett * here or we would add an extra fput for file 2663e99668a5SLiam R. Howlett * and cause general protection fault 2664e99668a5SLiam R. Howlett * ultimately. 2665e99668a5SLiam R. Howlett */ 2666e99668a5SLiam R. Howlett fput(vma->vm_file); 2667e99668a5SLiam R. Howlett vm_area_free(vma); 2668e99668a5SLiam R. Howlett vma = merge; 2669e99668a5SLiam R. Howlett /* Update vm_flags to pick up the change. */ 2670e99668a5SLiam R. Howlett addr = vma->vm_start; 2671e99668a5SLiam R. Howlett vm_flags = vma->vm_flags; 2672e99668a5SLiam R. Howlett goto unmap_writable; 2673e99668a5SLiam R. Howlett } 2674e99668a5SLiam R. Howlett } 2675e99668a5SLiam R. Howlett 2676e99668a5SLiam R. Howlett vm_flags = vma->vm_flags; 2677e99668a5SLiam R. Howlett } else if (vm_flags & VM_SHARED) { 2678e99668a5SLiam R. Howlett error = shmem_zero_setup(vma); 2679e99668a5SLiam R. Howlett if (error) 2680e99668a5SLiam R. Howlett goto free_vma; 2681e99668a5SLiam R. Howlett } else { 2682e99668a5SLiam R. Howlett vma_set_anonymous(vma); 2683e99668a5SLiam R. Howlett } 2684e99668a5SLiam R. Howlett 2685e99668a5SLiam R. Howlett /* Allow architectures to sanity-check the vm_flags */ 2686e99668a5SLiam R. Howlett if (!arch_validate_flags(vma->vm_flags)) { 2687e99668a5SLiam R. Howlett error = -EINVAL; 2688e99668a5SLiam R. Howlett if (file) 2689e99668a5SLiam R. Howlett goto unmap_and_free_vma; 2690e99668a5SLiam R. Howlett else 2691e99668a5SLiam R. Howlett goto free_vma; 2692e99668a5SLiam R. Howlett } 2693e99668a5SLiam R. Howlett 2694e99668a5SLiam R. Howlett if (mas_preallocate(&mas, vma, GFP_KERNEL)) { 2695e99668a5SLiam R. Howlett error = -ENOMEM; 2696e99668a5SLiam R. Howlett if (file) 2697e99668a5SLiam R. Howlett goto unmap_and_free_vma; 2698e99668a5SLiam R. Howlett else 2699e99668a5SLiam R. Howlett goto free_vma; 2700e99668a5SLiam R. Howlett } 2701e99668a5SLiam R. Howlett 2702e99668a5SLiam R. Howlett if (vma->vm_file) 2703e99668a5SLiam R. Howlett i_mmap_lock_write(vma->vm_file->f_mapping); 2704e99668a5SLiam R. Howlett 2705e99668a5SLiam R. Howlett vma_mas_store(vma, &mas); 2706e99668a5SLiam R. Howlett mm->map_count++; 2707e99668a5SLiam R. Howlett if (vma->vm_file) { 2708e99668a5SLiam R. Howlett if (vma->vm_flags & VM_SHARED) 2709e99668a5SLiam R. Howlett mapping_allow_writable(vma->vm_file->f_mapping); 2710e99668a5SLiam R. Howlett 2711e99668a5SLiam R. Howlett flush_dcache_mmap_lock(vma->vm_file->f_mapping); 2712e99668a5SLiam R. Howlett vma_interval_tree_insert(vma, &vma->vm_file->f_mapping->i_mmap); 2713e99668a5SLiam R. Howlett flush_dcache_mmap_unlock(vma->vm_file->f_mapping); 2714e99668a5SLiam R. Howlett i_mmap_unlock_write(vma->vm_file->f_mapping); 2715e99668a5SLiam R. Howlett } 2716e99668a5SLiam R. Howlett 2717e99668a5SLiam R. Howlett /* 2718e99668a5SLiam R. Howlett * vma_merge() calls khugepaged_enter_vma() either, the below 2719e99668a5SLiam R. Howlett * call covers the non-merge case. 2720e99668a5SLiam R. Howlett */ 2721e99668a5SLiam R. Howlett khugepaged_enter_vma(vma, vma->vm_flags); 2722e99668a5SLiam R. Howlett 2723e99668a5SLiam R. Howlett /* Once vma denies write, undo our temporary denial count */ 2724e99668a5SLiam R. Howlett unmap_writable: 2725e99668a5SLiam R. Howlett if (file && vm_flags & VM_SHARED) 2726e99668a5SLiam R. Howlett mapping_unmap_writable(file->f_mapping); 2727e99668a5SLiam R. Howlett file = vma->vm_file; 2728e99668a5SLiam R. Howlett expanded: 2729e99668a5SLiam R. Howlett perf_event_mmap(vma); 2730e99668a5SLiam R. Howlett 2731e99668a5SLiam R. Howlett vm_stat_account(mm, vm_flags, len >> PAGE_SHIFT); 2732e99668a5SLiam R. Howlett if (vm_flags & VM_LOCKED) { 2733e99668a5SLiam R. Howlett if ((vm_flags & VM_SPECIAL) || vma_is_dax(vma) || 2734e99668a5SLiam R. Howlett is_vm_hugetlb_page(vma) || 2735e99668a5SLiam R. Howlett vma == get_gate_vma(current->mm)) 2736e99668a5SLiam R. Howlett vma->vm_flags &= VM_LOCKED_CLEAR_MASK; 2737e99668a5SLiam R. Howlett else 2738e99668a5SLiam R. Howlett mm->locked_vm += (len >> PAGE_SHIFT); 2739e99668a5SLiam R. Howlett } 2740e99668a5SLiam R. Howlett 2741e99668a5SLiam R. Howlett if (file) 2742e99668a5SLiam R. Howlett uprobe_mmap(vma); 2743e99668a5SLiam R. Howlett 2744e99668a5SLiam R. Howlett /* 2745e99668a5SLiam R. Howlett * New (or expanded) vma always get soft dirty status. 2746e99668a5SLiam R. Howlett * Otherwise user-space soft-dirty page tracker won't 2747e99668a5SLiam R. Howlett * be able to distinguish situation when vma area unmapped, 2748e99668a5SLiam R. Howlett * then new mapped in-place (which must be aimed as 2749e99668a5SLiam R. Howlett * a completely new data area). 2750e99668a5SLiam R. Howlett */ 2751e99668a5SLiam R. Howlett vma->vm_flags |= VM_SOFTDIRTY; 2752e99668a5SLiam R. Howlett 2753e99668a5SLiam R. Howlett vma_set_page_prot(vma); 2754e99668a5SLiam R. Howlett 2755e99668a5SLiam R. Howlett validate_mm(mm); 2756e99668a5SLiam R. Howlett return addr; 2757e99668a5SLiam R. Howlett 2758e99668a5SLiam R. Howlett unmap_and_free_vma: 2759e99668a5SLiam R. Howlett fput(vma->vm_file); 2760e99668a5SLiam R. Howlett vma->vm_file = NULL; 2761e99668a5SLiam R. Howlett 2762e99668a5SLiam R. Howlett /* Undo any partial mapping done by a device driver. */ 2763763ecb03SLiam R. Howlett unmap_region(mm, mas.tree, vma, prev, next, vma->vm_start, vma->vm_end); 2764e99668a5SLiam R. Howlett if (vm_flags & VM_SHARED) 2765e99668a5SLiam R. Howlett mapping_unmap_writable(file->f_mapping); 2766e99668a5SLiam R. Howlett free_vma: 2767e99668a5SLiam R. Howlett vm_area_free(vma); 2768e99668a5SLiam R. Howlett unacct_error: 2769e99668a5SLiam R. Howlett if (charged) 2770e99668a5SLiam R. Howlett vm_unacct_memory(charged); 2771e99668a5SLiam R. Howlett validate_mm(mm); 2772e99668a5SLiam R. Howlett return error; 2773e99668a5SLiam R. Howlett } 2774e99668a5SLiam R. Howlett 2775dd2283f2SYang Shi static int __vm_munmap(unsigned long start, size_t len, bool downgrade) 2776a46ef99dSLinus Torvalds { 2777a46ef99dSLinus Torvalds int ret; 2778bfce281cSAl Viro struct mm_struct *mm = current->mm; 2779897ab3e0SMike Rapoport LIST_HEAD(uf); 278011f9a21aSLiam R. Howlett MA_STATE(mas, &mm->mm_mt, start, start); 2781a46ef99dSLinus Torvalds 2782d8ed45c5SMichel Lespinasse if (mmap_write_lock_killable(mm)) 2783ae798783SMichal Hocko return -EINTR; 2784ae798783SMichal Hocko 278511f9a21aSLiam R. Howlett ret = do_mas_munmap(&mas, mm, start, len, &uf, downgrade); 2786dd2283f2SYang Shi /* 2787c1e8d7c6SMichel Lespinasse * Returning 1 indicates mmap_lock is downgraded. 2788dd2283f2SYang Shi * But 1 is not legal return value of vm_munmap() and munmap(), reset 2789dd2283f2SYang Shi * it to 0 before return. 2790dd2283f2SYang Shi */ 2791dd2283f2SYang Shi if (ret == 1) { 2792d8ed45c5SMichel Lespinasse mmap_read_unlock(mm); 2793dd2283f2SYang Shi ret = 0; 2794dd2283f2SYang Shi } else 2795d8ed45c5SMichel Lespinasse mmap_write_unlock(mm); 2796dd2283f2SYang Shi 2797897ab3e0SMike Rapoport userfaultfd_unmap_complete(mm, &uf); 2798a46ef99dSLinus Torvalds return ret; 2799a46ef99dSLinus Torvalds } 2800dd2283f2SYang Shi 2801dd2283f2SYang Shi int vm_munmap(unsigned long start, size_t len) 2802dd2283f2SYang Shi { 2803dd2283f2SYang Shi return __vm_munmap(start, len, false); 2804dd2283f2SYang Shi } 2805a46ef99dSLinus Torvalds EXPORT_SYMBOL(vm_munmap); 2806a46ef99dSLinus Torvalds 28076a6160a7SHeiko Carstens SYSCALL_DEFINE2(munmap, unsigned long, addr, size_t, len) 28081da177e4SLinus Torvalds { 2809ce18d171SCatalin Marinas addr = untagged_addr(addr); 2810dd2283f2SYang Shi return __vm_munmap(addr, len, true); 28111da177e4SLinus Torvalds } 28121da177e4SLinus Torvalds 2813c8d78c18SKirill A. Shutemov 2814c8d78c18SKirill A. Shutemov /* 2815c8d78c18SKirill A. Shutemov * Emulation of deprecated remap_file_pages() syscall. 2816c8d78c18SKirill A. Shutemov */ 2817c8d78c18SKirill A. Shutemov SYSCALL_DEFINE5(remap_file_pages, unsigned long, start, unsigned long, size, 2818c8d78c18SKirill A. Shutemov unsigned long, prot, unsigned long, pgoff, unsigned long, flags) 2819c8d78c18SKirill A. Shutemov { 2820c8d78c18SKirill A. Shutemov 2821c8d78c18SKirill A. Shutemov struct mm_struct *mm = current->mm; 2822c8d78c18SKirill A. Shutemov struct vm_area_struct *vma; 2823c8d78c18SKirill A. Shutemov unsigned long populate = 0; 2824c8d78c18SKirill A. Shutemov unsigned long ret = -EINVAL; 2825c8d78c18SKirill A. Shutemov struct file *file; 2826c8d78c18SKirill A. Shutemov 2827ee65728eSMike Rapoport pr_warn_once("%s (%d) uses deprecated remap_file_pages() syscall. See Documentation/mm/remap_file_pages.rst.\n", 2828c8d78c18SKirill A. Shutemov current->comm, current->pid); 2829c8d78c18SKirill A. Shutemov 2830c8d78c18SKirill A. Shutemov if (prot) 2831c8d78c18SKirill A. Shutemov return ret; 2832c8d78c18SKirill A. Shutemov start = start & PAGE_MASK; 2833c8d78c18SKirill A. Shutemov size = size & PAGE_MASK; 2834c8d78c18SKirill A. Shutemov 2835c8d78c18SKirill A. Shutemov if (start + size <= start) 2836c8d78c18SKirill A. Shutemov return ret; 2837c8d78c18SKirill A. Shutemov 2838c8d78c18SKirill A. Shutemov /* Does pgoff wrap? */ 2839c8d78c18SKirill A. Shutemov if (pgoff + (size >> PAGE_SHIFT) < pgoff) 2840c8d78c18SKirill A. Shutemov return ret; 2841c8d78c18SKirill A. Shutemov 2842d8ed45c5SMichel Lespinasse if (mmap_write_lock_killable(mm)) 2843dc0ef0dfSMichal Hocko return -EINTR; 2844dc0ef0dfSMichal Hocko 28459b593cb2SLiam R. Howlett vma = vma_lookup(mm, start); 2846c8d78c18SKirill A. Shutemov 2847c8d78c18SKirill A. Shutemov if (!vma || !(vma->vm_flags & VM_SHARED)) 2848c8d78c18SKirill A. Shutemov goto out; 2849c8d78c18SKirill A. Shutemov 285048f7df32SKirill A. Shutemov if (start + size > vma->vm_end) { 2851763ecb03SLiam R. Howlett VMA_ITERATOR(vmi, mm, vma->vm_end); 2852763ecb03SLiam R. Howlett struct vm_area_struct *next, *prev = vma; 285348f7df32SKirill A. Shutemov 2854763ecb03SLiam R. Howlett for_each_vma_range(vmi, next, start + size) { 285548f7df32SKirill A. Shutemov /* hole between vmas ? */ 2856763ecb03SLiam R. Howlett if (next->vm_start != prev->vm_end) 285748f7df32SKirill A. Shutemov goto out; 285848f7df32SKirill A. Shutemov 285948f7df32SKirill A. Shutemov if (next->vm_file != vma->vm_file) 286048f7df32SKirill A. Shutemov goto out; 286148f7df32SKirill A. Shutemov 286248f7df32SKirill A. Shutemov if (next->vm_flags != vma->vm_flags) 286348f7df32SKirill A. Shutemov goto out; 286448f7df32SKirill A. Shutemov 2865763ecb03SLiam R. Howlett prev = next; 286648f7df32SKirill A. Shutemov } 286748f7df32SKirill A. Shutemov 286848f7df32SKirill A. Shutemov if (!next) 2869c8d78c18SKirill A. Shutemov goto out; 2870c8d78c18SKirill A. Shutemov } 2871c8d78c18SKirill A. Shutemov 2872c8d78c18SKirill A. Shutemov prot |= vma->vm_flags & VM_READ ? PROT_READ : 0; 2873c8d78c18SKirill A. Shutemov prot |= vma->vm_flags & VM_WRITE ? PROT_WRITE : 0; 2874c8d78c18SKirill A. Shutemov prot |= vma->vm_flags & VM_EXEC ? PROT_EXEC : 0; 2875c8d78c18SKirill A. Shutemov 2876c8d78c18SKirill A. Shutemov flags &= MAP_NONBLOCK; 2877c8d78c18SKirill A. Shutemov flags |= MAP_SHARED | MAP_FIXED | MAP_POPULATE; 2878fce000b1SLiam Howlett if (vma->vm_flags & VM_LOCKED) 2879c8d78c18SKirill A. Shutemov flags |= MAP_LOCKED; 288048f7df32SKirill A. Shutemov 2881c8d78c18SKirill A. Shutemov file = get_file(vma->vm_file); 288245e55300SPeter Collingbourne ret = do_mmap(vma->vm_file, start, size, 2883897ab3e0SMike Rapoport prot, flags, pgoff, &populate, NULL); 2884c8d78c18SKirill A. Shutemov fput(file); 2885c8d78c18SKirill A. Shutemov out: 2886d8ed45c5SMichel Lespinasse mmap_write_unlock(mm); 2887c8d78c18SKirill A. Shutemov if (populate) 2888c8d78c18SKirill A. Shutemov mm_populate(ret, populate); 2889c8d78c18SKirill A. Shutemov if (!IS_ERR_VALUE(ret)) 2890c8d78c18SKirill A. Shutemov ret = 0; 2891c8d78c18SKirill A. Shutemov return ret; 2892c8d78c18SKirill A. Shutemov } 2893c8d78c18SKirill A. Shutemov 28941da177e4SLinus Torvalds /* 28952e7ce7d3SLiam R. Howlett * brk_munmap() - Unmap a parital vma. 28962e7ce7d3SLiam R. Howlett * @mas: The maple tree state. 28972e7ce7d3SLiam R. Howlett * @vma: The vma to be modified 28982e7ce7d3SLiam R. Howlett * @newbrk: the start of the address to unmap 28992e7ce7d3SLiam R. Howlett * @oldbrk: The end of the address to unmap 29002e7ce7d3SLiam R. Howlett * @uf: The userfaultfd list_head 29012e7ce7d3SLiam R. Howlett * 29022e7ce7d3SLiam R. Howlett * Returns: 1 on success. 29032e7ce7d3SLiam R. Howlett * unmaps a partial VMA mapping. Does not handle alignment, downgrades lock if 29042e7ce7d3SLiam R. Howlett * possible. 29051da177e4SLinus Torvalds */ 29062e7ce7d3SLiam R. Howlett static int do_brk_munmap(struct ma_state *mas, struct vm_area_struct *vma, 29072e7ce7d3SLiam R. Howlett unsigned long newbrk, unsigned long oldbrk, 29082e7ce7d3SLiam R. Howlett struct list_head *uf) 29092e7ce7d3SLiam R. Howlett { 29102e7ce7d3SLiam R. Howlett struct mm_struct *mm = vma->vm_mm; 29112e7ce7d3SLiam R. Howlett int ret; 29122e7ce7d3SLiam R. Howlett 29132e7ce7d3SLiam R. Howlett arch_unmap(mm, newbrk, oldbrk); 291467e7c167SLiam R. Howlett ret = do_mas_align_munmap(mas, vma, mm, newbrk, oldbrk, uf, true); 29152e7ce7d3SLiam R. Howlett validate_mm_mt(mm); 29162e7ce7d3SLiam R. Howlett return ret; 29172e7ce7d3SLiam R. Howlett } 29182e7ce7d3SLiam R. Howlett 29192e7ce7d3SLiam R. Howlett /* 29202e7ce7d3SLiam R. Howlett * do_brk_flags() - Increase the brk vma if the flags match. 29212e7ce7d3SLiam R. Howlett * @mas: The maple tree state. 29222e7ce7d3SLiam R. Howlett * @addr: The start address 29232e7ce7d3SLiam R. Howlett * @len: The length of the increase 29242e7ce7d3SLiam R. Howlett * @vma: The vma, 29252e7ce7d3SLiam R. Howlett * @flags: The VMA Flags 29262e7ce7d3SLiam R. Howlett * 29272e7ce7d3SLiam R. Howlett * Extend the brk VMA from addr to addr + len. If the VMA is NULL or the flags 29282e7ce7d3SLiam R. Howlett * do not match then create a new anonymous VMA. Eventually we may be able to 29292e7ce7d3SLiam R. Howlett * do some brk-specific accounting here. 29302e7ce7d3SLiam R. Howlett */ 29312e7ce7d3SLiam R. Howlett static int do_brk_flags(struct ma_state *mas, struct vm_area_struct *vma, 2932763ecb03SLiam R. Howlett unsigned long addr, unsigned long len, unsigned long flags) 29331da177e4SLinus Torvalds { 29341da177e4SLinus Torvalds struct mm_struct *mm = current->mm; 29352e7ce7d3SLiam R. Howlett 2936d4af56c5SLiam R. Howlett validate_mm_mt(mm); 29372e7ce7d3SLiam R. Howlett /* 29382e7ce7d3SLiam R. Howlett * Check against address space limits by the changed size 29392e7ce7d3SLiam R. Howlett * Note: This happens *after* clearing old mappings in some code paths. 29402e7ce7d3SLiam R. Howlett */ 294116e72e9bSDenys Vlasenko flags |= VM_DATA_DEFAULT_FLAGS | VM_ACCOUNT | mm->def_flags; 294284638335SKonstantin Khlebnikov if (!may_expand_vm(mm, flags, len >> PAGE_SHIFT)) 29431da177e4SLinus Torvalds return -ENOMEM; 29441da177e4SLinus Torvalds 29451da177e4SLinus Torvalds if (mm->map_count > sysctl_max_map_count) 29461da177e4SLinus Torvalds return -ENOMEM; 29471da177e4SLinus Torvalds 2948191c5424SAl Viro if (security_vm_enough_memory_mm(mm, len >> PAGE_SHIFT)) 29491da177e4SLinus Torvalds return -ENOMEM; 29501da177e4SLinus Torvalds 29511da177e4SLinus Torvalds /* 29522e7ce7d3SLiam R. Howlett * Expand the existing vma if possible; Note that singular lists do not 29532e7ce7d3SLiam R. Howlett * occur after forking, so the expand will only happen on new VMAs. 29541da177e4SLinus Torvalds */ 29552e7ce7d3SLiam R. Howlett if (vma && 29562e7ce7d3SLiam R. Howlett (!vma->anon_vma || list_is_singular(&vma->anon_vma_chain)) && 29572e7ce7d3SLiam R. Howlett ((vma->vm_flags & ~VM_SOFTDIRTY) == flags)) { 29582e7ce7d3SLiam R. Howlett mas->index = vma->vm_start; 29592e7ce7d3SLiam R. Howlett mas->last = addr + len - 1; 29602e7ce7d3SLiam R. Howlett vma_adjust_trans_huge(vma, addr, addr + len, 0); 29612e7ce7d3SLiam R. Howlett if (vma->anon_vma) { 29622e7ce7d3SLiam R. Howlett anon_vma_lock_write(vma->anon_vma); 29632e7ce7d3SLiam R. Howlett anon_vma_interval_tree_pre_update_vma(vma); 29641da177e4SLinus Torvalds } 29652e7ce7d3SLiam R. Howlett vma->vm_end = addr + len; 29662e7ce7d3SLiam R. Howlett vma->vm_flags |= VM_SOFTDIRTY; 29672e7ce7d3SLiam R. Howlett if (mas_store_gfp(mas, vma, GFP_KERNEL)) 29682e7ce7d3SLiam R. Howlett goto mas_expand_failed; 29692e7ce7d3SLiam R. Howlett 29702e7ce7d3SLiam R. Howlett if (vma->anon_vma) { 29712e7ce7d3SLiam R. Howlett anon_vma_interval_tree_post_update_vma(vma); 29722e7ce7d3SLiam R. Howlett anon_vma_unlock_write(vma->anon_vma); 29732e7ce7d3SLiam R. Howlett } 29742e7ce7d3SLiam R. Howlett khugepaged_enter_vma(vma, flags); 29752e7ce7d3SLiam R. Howlett goto out; 29762e7ce7d3SLiam R. Howlett } 29772e7ce7d3SLiam R. Howlett 29782e7ce7d3SLiam R. Howlett /* create a vma struct for an anonymous mapping */ 29792e7ce7d3SLiam R. Howlett vma = vm_area_alloc(mm); 29802e7ce7d3SLiam R. Howlett if (!vma) 29812e7ce7d3SLiam R. Howlett goto vma_alloc_fail; 29821da177e4SLinus Torvalds 2983bfd40eafSKirill A. Shutemov vma_set_anonymous(vma); 29841da177e4SLinus Torvalds vma->vm_start = addr; 29851da177e4SLinus Torvalds vma->vm_end = addr + len; 29862e7ce7d3SLiam R. Howlett vma->vm_pgoff = addr >> PAGE_SHIFT; 29871da177e4SLinus Torvalds vma->vm_flags = flags; 29883ed75eb8SColy Li vma->vm_page_prot = vm_get_page_prot(flags); 29892e7ce7d3SLiam R. Howlett mas_set_range(mas, vma->vm_start, addr + len - 1); 29902e7ce7d3SLiam R. Howlett if (mas_store_gfp(mas, vma, GFP_KERNEL)) 29912e7ce7d3SLiam R. Howlett goto mas_store_fail; 2992d4af56c5SLiam R. Howlett 29932e7ce7d3SLiam R. Howlett mm->map_count++; 29941da177e4SLinus Torvalds out: 29953af9e859SEric B Munson perf_event_mmap(vma); 29961da177e4SLinus Torvalds mm->total_vm += len >> PAGE_SHIFT; 299784638335SKonstantin Khlebnikov mm->data_vm += len >> PAGE_SHIFT; 2998128557ffSMichel Lespinasse if (flags & VM_LOCKED) 2999ba470de4SRik van Riel mm->locked_vm += (len >> PAGE_SHIFT); 3000d9104d1cSCyrill Gorcunov vma->vm_flags |= VM_SOFTDIRTY; 3001763ecb03SLiam R. Howlett validate_mm(mm); 30025d22fc25SLinus Torvalds return 0; 3003d4af56c5SLiam R. Howlett 30042e7ce7d3SLiam R. Howlett mas_store_fail: 3005d4af56c5SLiam R. Howlett vm_area_free(vma); 30062e7ce7d3SLiam R. Howlett vma_alloc_fail: 30072e7ce7d3SLiam R. Howlett vm_unacct_memory(len >> PAGE_SHIFT); 30082e7ce7d3SLiam R. Howlett return -ENOMEM; 30092e7ce7d3SLiam R. Howlett 30102e7ce7d3SLiam R. Howlett mas_expand_failed: 30112e7ce7d3SLiam R. Howlett if (vma->anon_vma) { 30122e7ce7d3SLiam R. Howlett anon_vma_interval_tree_post_update_vma(vma); 30132e7ce7d3SLiam R. Howlett anon_vma_unlock_write(vma->anon_vma); 30142e7ce7d3SLiam R. Howlett } 3015d4af56c5SLiam R. Howlett return -ENOMEM; 30161da177e4SLinus Torvalds } 30171da177e4SLinus Torvalds 3018bb177a73SMichal Hocko int vm_brk_flags(unsigned long addr, unsigned long request, unsigned long flags) 3019e4eb1ff6SLinus Torvalds { 3020e4eb1ff6SLinus Torvalds struct mm_struct *mm = current->mm; 30212e7ce7d3SLiam R. Howlett struct vm_area_struct *vma = NULL; 3022bb177a73SMichal Hocko unsigned long len; 30235d22fc25SLinus Torvalds int ret; 3024128557ffSMichel Lespinasse bool populate; 3025897ab3e0SMike Rapoport LIST_HEAD(uf); 30262e7ce7d3SLiam R. Howlett MA_STATE(mas, &mm->mm_mt, addr, addr); 3027e4eb1ff6SLinus Torvalds 3028bb177a73SMichal Hocko len = PAGE_ALIGN(request); 3029bb177a73SMichal Hocko if (len < request) 3030bb177a73SMichal Hocko return -ENOMEM; 3031bb177a73SMichal Hocko if (!len) 3032bb177a73SMichal Hocko return 0; 3033bb177a73SMichal Hocko 3034d8ed45c5SMichel Lespinasse if (mmap_write_lock_killable(mm)) 30352d6c9282SMichal Hocko return -EINTR; 30362d6c9282SMichal Hocko 30372e7ce7d3SLiam R. Howlett /* Until we need other flags, refuse anything except VM_EXEC. */ 30382e7ce7d3SLiam R. Howlett if ((flags & (~VM_EXEC)) != 0) 30392e7ce7d3SLiam R. Howlett return -EINVAL; 30402e7ce7d3SLiam R. Howlett 30412e7ce7d3SLiam R. Howlett ret = check_brk_limits(addr, len); 30422e7ce7d3SLiam R. Howlett if (ret) 30432e7ce7d3SLiam R. Howlett goto limits_failed; 30442e7ce7d3SLiam R. Howlett 304511f9a21aSLiam R. Howlett ret = do_mas_munmap(&mas, mm, addr, len, &uf, 0); 30462e7ce7d3SLiam R. Howlett if (ret) 30472e7ce7d3SLiam R. Howlett goto munmap_failed; 30482e7ce7d3SLiam R. Howlett 30492e7ce7d3SLiam R. Howlett vma = mas_prev(&mas, 0); 30502e7ce7d3SLiam R. Howlett if (!vma || vma->vm_end != addr || vma_policy(vma) || 30512e7ce7d3SLiam R. Howlett !can_vma_merge_after(vma, flags, NULL, NULL, 30522e7ce7d3SLiam R. Howlett addr >> PAGE_SHIFT, NULL_VM_UFFD_CTX, NULL)) 30532e7ce7d3SLiam R. Howlett vma = NULL; 30542e7ce7d3SLiam R. Howlett 30552e7ce7d3SLiam R. Howlett ret = do_brk_flags(&mas, vma, addr, len, flags); 3056128557ffSMichel Lespinasse populate = ((mm->def_flags & VM_LOCKED) != 0); 3057d8ed45c5SMichel Lespinasse mmap_write_unlock(mm); 3058897ab3e0SMike Rapoport userfaultfd_unmap_complete(mm, &uf); 30595d22fc25SLinus Torvalds if (populate && !ret) 3060128557ffSMichel Lespinasse mm_populate(addr, len); 3061e4eb1ff6SLinus Torvalds return ret; 30622e7ce7d3SLiam R. Howlett 30632e7ce7d3SLiam R. Howlett munmap_failed: 30642e7ce7d3SLiam R. Howlett limits_failed: 30652e7ce7d3SLiam R. Howlett mmap_write_unlock(mm); 30662e7ce7d3SLiam R. Howlett return ret; 3067e4eb1ff6SLinus Torvalds } 306816e72e9bSDenys Vlasenko EXPORT_SYMBOL(vm_brk_flags); 306916e72e9bSDenys Vlasenko 307016e72e9bSDenys Vlasenko int vm_brk(unsigned long addr, unsigned long len) 307116e72e9bSDenys Vlasenko { 307216e72e9bSDenys Vlasenko return vm_brk_flags(addr, len, 0); 307316e72e9bSDenys Vlasenko } 3074e4eb1ff6SLinus Torvalds EXPORT_SYMBOL(vm_brk); 30751da177e4SLinus Torvalds 30761da177e4SLinus Torvalds /* Release all mmaps. */ 30771da177e4SLinus Torvalds void exit_mmap(struct mm_struct *mm) 30781da177e4SLinus Torvalds { 3079d16dfc55SPeter Zijlstra struct mmu_gather tlb; 3080ba470de4SRik van Riel struct vm_area_struct *vma; 30811da177e4SLinus Torvalds unsigned long nr_accounted = 0; 3082763ecb03SLiam R. Howlett MA_STATE(mas, &mm->mm_mt, 0, 0); 3083763ecb03SLiam R. Howlett int count = 0; 30841da177e4SLinus Torvalds 3085d6dd61c8SJeremy Fitzhardinge /* mm's last user has gone, and its about to be pulled down */ 3086cddb8a5cSAndrea Arcangeli mmu_notifier_release(mm); 3087d6dd61c8SJeremy Fitzhardinge 308827ae357fSDavid Rientjes if (unlikely(mm_is_oom_victim(mm))) { 308927ae357fSDavid Rientjes /* 309027ae357fSDavid Rientjes * Manually reap the mm to free as much memory as possible. 309127ae357fSDavid Rientjes * Then, as the oom reaper does, set MMF_OOM_SKIP to disregard 3092c1e8d7c6SMichel Lespinasse * this mm from further consideration. Taking mm->mmap_lock for 309327ae357fSDavid Rientjes * write after setting MMF_OOM_SKIP will guarantee that the oom 3094c1e8d7c6SMichel Lespinasse * reaper will not run on this mm again after mmap_lock is 309527ae357fSDavid Rientjes * dropped. 309627ae357fSDavid Rientjes * 3097c1e8d7c6SMichel Lespinasse * Nothing can be holding mm->mmap_lock here and the above call 309827ae357fSDavid Rientjes * to mmu_notifier_release(mm) ensures mmu notifier callbacks in 309927ae357fSDavid Rientjes * __oom_reap_task_mm() will not block. 310027ae357fSDavid Rientjes */ 310193065ac7SMichal Hocko (void)__oom_reap_task_mm(mm); 310227ae357fSDavid Rientjes set_bit(MMF_OOM_SKIP, &mm->flags); 310327ae357fSDavid Rientjes } 310427ae357fSDavid Rientjes 310564591e86SSuren Baghdasaryan mmap_write_lock(mm); 31069480c53eSJeremy Fitzhardinge arch_exit_mmap(mm); 31079480c53eSJeremy Fitzhardinge 3108763ecb03SLiam R. Howlett vma = mas_find(&mas, ULONG_MAX); 310964591e86SSuren Baghdasaryan if (!vma) { 311064591e86SSuren Baghdasaryan /* Can happen if dup_mmap() received an OOM */ 311164591e86SSuren Baghdasaryan mmap_write_unlock(mm); 31129480c53eSJeremy Fitzhardinge return; 311364591e86SSuren Baghdasaryan } 31149480c53eSJeremy Fitzhardinge 31151da177e4SLinus Torvalds lru_add_drain(); 31161da177e4SLinus Torvalds flush_cache_mm(mm); 3117d8b45053SWill Deacon tlb_gather_mmu_fullmm(&tlb, mm); 3118901608d9SOleg Nesterov /* update_hiwater_rss(mm) here? but nobody should be looking */ 3119763ecb03SLiam R. Howlett /* Use ULONG_MAX here to ensure all VMAs in the mm are unmapped */ 3120763ecb03SLiam R. Howlett unmap_vmas(&tlb, &mm->mm_mt, vma, 0, ULONG_MAX); 3121763ecb03SLiam R. Howlett free_pgtables(&tlb, &mm->mm_mt, vma, FIRST_USER_ADDRESS, 3122763ecb03SLiam R. Howlett USER_PGTABLES_CEILING); 3123ae8eba8bSWill Deacon tlb_finish_mmu(&tlb); 31241da177e4SLinus Torvalds 3125763ecb03SLiam R. Howlett /* 3126763ecb03SLiam R. Howlett * Walk the list again, actually closing and freeing it, with preemption 3127763ecb03SLiam R. Howlett * enabled, without holding any MM locks besides the unreachable 3128763ecb03SLiam R. Howlett * mmap_write_lock. 3129763ecb03SLiam R. Howlett */ 3130763ecb03SLiam R. Howlett do { 31314f74d2c8SLinus Torvalds if (vma->vm_flags & VM_ACCOUNT) 31324f74d2c8SLinus Torvalds nr_accounted += vma_pages(vma); 3133763ecb03SLiam R. Howlett remove_vma(vma); 3134763ecb03SLiam R. Howlett count++; 31350a3b3c25SPaul E. McKenney cond_resched(); 3136763ecb03SLiam R. Howlett } while ((vma = mas_find(&mas, ULONG_MAX)) != NULL); 3137763ecb03SLiam R. Howlett 3138763ecb03SLiam R. Howlett BUG_ON(count != mm->map_count); 3139d4af56c5SLiam R. Howlett 3140d4af56c5SLiam R. Howlett trace_exit_mmap(mm); 3141d4af56c5SLiam R. Howlett __mt_destroy(&mm->mm_mt); 314264591e86SSuren Baghdasaryan mmap_write_unlock(mm); 31434f74d2c8SLinus Torvalds vm_unacct_memory(nr_accounted); 31441da177e4SLinus Torvalds } 31451da177e4SLinus Torvalds 31461da177e4SLinus Torvalds /* Insert vm structure into process list sorted by address 31471da177e4SLinus Torvalds * and into the inode's i_mmap tree. If vm_file is non-NULL 3148c8c06efaSDavidlohr Bueso * then i_mmap_rwsem is taken here. 31491da177e4SLinus Torvalds */ 31501da177e4SLinus Torvalds int insert_vm_struct(struct mm_struct *mm, struct vm_area_struct *vma) 31511da177e4SLinus Torvalds { 3152d4af56c5SLiam R. Howlett unsigned long charged = vma_pages(vma); 31531da177e4SLinus Torvalds 3154d4af56c5SLiam R. Howlett 3155d0601a50SLiam R. Howlett if (find_vma_intersection(mm, vma->vm_start, vma->vm_end)) 3156c9d13f5fSChen Gang return -ENOMEM; 3157d4af56c5SLiam R. Howlett 3158c9d13f5fSChen Gang if ((vma->vm_flags & VM_ACCOUNT) && 3159d4af56c5SLiam R. Howlett security_vm_enough_memory_mm(mm, charged)) 3160c9d13f5fSChen Gang return -ENOMEM; 3161c9d13f5fSChen Gang 31621da177e4SLinus Torvalds /* 31631da177e4SLinus Torvalds * The vm_pgoff of a purely anonymous vma should be irrelevant 31641da177e4SLinus Torvalds * until its first write fault, when page's anon_vma and index 31651da177e4SLinus Torvalds * are set. But now set the vm_pgoff it will almost certainly 31661da177e4SLinus Torvalds * end up with (unless mremap moves it elsewhere before that 31671da177e4SLinus Torvalds * first wfault), so /proc/pid/maps tells a consistent story. 31681da177e4SLinus Torvalds * 31691da177e4SLinus Torvalds * By setting it to reflect the virtual start address of the 31701da177e4SLinus Torvalds * vma, merges and splits can happen in a seamless way, just 31711da177e4SLinus Torvalds * using the existing file pgoff checks and manipulations. 31728332326eSLiao Pingfang * Similarly in do_mmap and in do_brk_flags. 31731da177e4SLinus Torvalds */ 31748a9cc3b5SOleg Nesterov if (vma_is_anonymous(vma)) { 31751da177e4SLinus Torvalds BUG_ON(vma->anon_vma); 31761da177e4SLinus Torvalds vma->vm_pgoff = vma->vm_start >> PAGE_SHIFT; 31771da177e4SLinus Torvalds } 31782b144498SSrikar Dronamraju 3179763ecb03SLiam R. Howlett if (vma_link(mm, vma)) { 3180d4af56c5SLiam R. Howlett vm_unacct_memory(charged); 3181d4af56c5SLiam R. Howlett return -ENOMEM; 3182d4af56c5SLiam R. Howlett } 3183d4af56c5SLiam R. Howlett 31841da177e4SLinus Torvalds return 0; 31851da177e4SLinus Torvalds } 31861da177e4SLinus Torvalds 31871da177e4SLinus Torvalds /* 31881da177e4SLinus Torvalds * Copy the vma structure to a new location in the same mm, 31891da177e4SLinus Torvalds * prior to moving page table entries, to effect an mremap move. 31901da177e4SLinus Torvalds */ 31911da177e4SLinus Torvalds struct vm_area_struct *copy_vma(struct vm_area_struct **vmap, 319238a76013SMichel Lespinasse unsigned long addr, unsigned long len, pgoff_t pgoff, 319338a76013SMichel Lespinasse bool *need_rmap_locks) 31941da177e4SLinus Torvalds { 31951da177e4SLinus Torvalds struct vm_area_struct *vma = *vmap; 31961da177e4SLinus Torvalds unsigned long vma_start = vma->vm_start; 31971da177e4SLinus Torvalds struct mm_struct *mm = vma->vm_mm; 31981da177e4SLinus Torvalds struct vm_area_struct *new_vma, *prev; 3199948f017bSAndrea Arcangeli bool faulted_in_anon_vma = true; 32001da177e4SLinus Torvalds 3201d4af56c5SLiam R. Howlett validate_mm_mt(mm); 32021da177e4SLinus Torvalds /* 32031da177e4SLinus Torvalds * If anonymous vma has not yet been faulted, update new pgoff 32041da177e4SLinus Torvalds * to match new location, to increase its chance of merging. 32051da177e4SLinus Torvalds */ 3206ce75799bSOleg Nesterov if (unlikely(vma_is_anonymous(vma) && !vma->anon_vma)) { 32071da177e4SLinus Torvalds pgoff = addr >> PAGE_SHIFT; 3208948f017bSAndrea Arcangeli faulted_in_anon_vma = false; 3209948f017bSAndrea Arcangeli } 32101da177e4SLinus Torvalds 3211763ecb03SLiam R. Howlett new_vma = find_vma_prev(mm, addr, &prev); 3212763ecb03SLiam R. Howlett if (new_vma && new_vma->vm_start < addr + len) 32136597d783SHugh Dickins return NULL; /* should never get here */ 3214524e00b3SLiam R. Howlett 32151da177e4SLinus Torvalds new_vma = vma_merge(mm, prev, addr, addr + len, vma->vm_flags, 321619a809afSAndrea Arcangeli vma->anon_vma, vma->vm_file, pgoff, vma_policy(vma), 32175c26f6acSSuren Baghdasaryan vma->vm_userfaultfd_ctx, anon_vma_name(vma)); 32181da177e4SLinus Torvalds if (new_vma) { 32191da177e4SLinus Torvalds /* 32201da177e4SLinus Torvalds * Source vma may have been merged into new_vma 32211da177e4SLinus Torvalds */ 3222948f017bSAndrea Arcangeli if (unlikely(vma_start >= new_vma->vm_start && 3223948f017bSAndrea Arcangeli vma_start < new_vma->vm_end)) { 3224948f017bSAndrea Arcangeli /* 3225948f017bSAndrea Arcangeli * The only way we can get a vma_merge with 3226948f017bSAndrea Arcangeli * self during an mremap is if the vma hasn't 3227948f017bSAndrea Arcangeli * been faulted in yet and we were allowed to 3228948f017bSAndrea Arcangeli * reset the dst vma->vm_pgoff to the 3229948f017bSAndrea Arcangeli * destination address of the mremap to allow 3230948f017bSAndrea Arcangeli * the merge to happen. mremap must change the 3231948f017bSAndrea Arcangeli * vm_pgoff linearity between src and dst vmas 3232948f017bSAndrea Arcangeli * (in turn preventing a vma_merge) to be 3233948f017bSAndrea Arcangeli * safe. It is only safe to keep the vm_pgoff 3234948f017bSAndrea Arcangeli * linear if there are no pages mapped yet. 3235948f017bSAndrea Arcangeli */ 323681d1b09cSSasha Levin VM_BUG_ON_VMA(faulted_in_anon_vma, new_vma); 323738a76013SMichel Lespinasse *vmap = vma = new_vma; 3238108d6642SMichel Lespinasse } 323938a76013SMichel Lespinasse *need_rmap_locks = (new_vma->vm_pgoff <= vma->vm_pgoff); 32401da177e4SLinus Torvalds } else { 32413928d4f5SLinus Torvalds new_vma = vm_area_dup(vma); 3242e3975891SChen Gang if (!new_vma) 3243e3975891SChen Gang goto out; 32441da177e4SLinus Torvalds new_vma->vm_start = addr; 32451da177e4SLinus Torvalds new_vma->vm_end = addr + len; 32461da177e4SLinus Torvalds new_vma->vm_pgoff = pgoff; 3247ef0855d3SOleg Nesterov if (vma_dup_policy(vma, new_vma)) 3248523d4e20SMichel Lespinasse goto out_free_vma; 3249523d4e20SMichel Lespinasse if (anon_vma_clone(new_vma, vma)) 3250523d4e20SMichel Lespinasse goto out_free_mempol; 3251e9714acfSKonstantin Khlebnikov if (new_vma->vm_file) 32521da177e4SLinus Torvalds get_file(new_vma->vm_file); 32531da177e4SLinus Torvalds if (new_vma->vm_ops && new_vma->vm_ops->open) 32541da177e4SLinus Torvalds new_vma->vm_ops->open(new_vma); 3255763ecb03SLiam R. Howlett if (vma_link(mm, new_vma)) 3256524e00b3SLiam R. Howlett goto out_vma_link; 325738a76013SMichel Lespinasse *need_rmap_locks = false; 32581da177e4SLinus Torvalds } 3259d4af56c5SLiam R. Howlett validate_mm_mt(mm); 32601da177e4SLinus Torvalds return new_vma; 32615beb4930SRik van Riel 3262524e00b3SLiam R. Howlett out_vma_link: 3263524e00b3SLiam R. Howlett if (new_vma->vm_ops && new_vma->vm_ops->close) 3264524e00b3SLiam R. Howlett new_vma->vm_ops->close(new_vma); 32655beb4930SRik van Riel out_free_mempol: 3266ef0855d3SOleg Nesterov mpol_put(vma_policy(new_vma)); 32675beb4930SRik van Riel out_free_vma: 32683928d4f5SLinus Torvalds vm_area_free(new_vma); 3269e3975891SChen Gang out: 3270d4af56c5SLiam R. Howlett validate_mm_mt(mm); 32715beb4930SRik van Riel return NULL; 32721da177e4SLinus Torvalds } 3273119f657cSakpm@osdl.org 3274119f657cSakpm@osdl.org /* 3275119f657cSakpm@osdl.org * Return true if the calling process may expand its vm space by the passed 3276119f657cSakpm@osdl.org * number of pages 3277119f657cSakpm@osdl.org */ 327884638335SKonstantin Khlebnikov bool may_expand_vm(struct mm_struct *mm, vm_flags_t flags, unsigned long npages) 3279119f657cSakpm@osdl.org { 328084638335SKonstantin Khlebnikov if (mm->total_vm + npages > rlimit(RLIMIT_AS) >> PAGE_SHIFT) 328184638335SKonstantin Khlebnikov return false; 3282119f657cSakpm@osdl.org 3283d977d56cSKonstantin Khlebnikov if (is_data_mapping(flags) && 3284d977d56cSKonstantin Khlebnikov mm->data_vm + npages > rlimit(RLIMIT_DATA) >> PAGE_SHIFT) { 3285f4fcd558SKonstantin Khlebnikov /* Workaround for Valgrind */ 3286f4fcd558SKonstantin Khlebnikov if (rlimit(RLIMIT_DATA) == 0 && 3287f4fcd558SKonstantin Khlebnikov mm->data_vm + npages <= rlimit_max(RLIMIT_DATA) >> PAGE_SHIFT) 3288f4fcd558SKonstantin Khlebnikov return true; 328957a7702bSDavid Woodhouse 329057a7702bSDavid Woodhouse pr_warn_once("%s (%d): VmData %lu exceed data ulimit %lu. Update limits%s.\n", 3291d977d56cSKonstantin Khlebnikov current->comm, current->pid, 3292d977d56cSKonstantin Khlebnikov (mm->data_vm + npages) << PAGE_SHIFT, 329357a7702bSDavid Woodhouse rlimit(RLIMIT_DATA), 329457a7702bSDavid Woodhouse ignore_rlimit_data ? "" : " or use boot option ignore_rlimit_data"); 329557a7702bSDavid Woodhouse 329657a7702bSDavid Woodhouse if (!ignore_rlimit_data) 3297d977d56cSKonstantin Khlebnikov return false; 3298d977d56cSKonstantin Khlebnikov } 3299119f657cSakpm@osdl.org 330084638335SKonstantin Khlebnikov return true; 330184638335SKonstantin Khlebnikov } 330284638335SKonstantin Khlebnikov 330384638335SKonstantin Khlebnikov void vm_stat_account(struct mm_struct *mm, vm_flags_t flags, long npages) 330484638335SKonstantin Khlebnikov { 33057866076bSPeng Liu WRITE_ONCE(mm->total_vm, READ_ONCE(mm->total_vm)+npages); 330684638335SKonstantin Khlebnikov 3307d977d56cSKonstantin Khlebnikov if (is_exec_mapping(flags)) 330884638335SKonstantin Khlebnikov mm->exec_vm += npages; 3309d977d56cSKonstantin Khlebnikov else if (is_stack_mapping(flags)) 331084638335SKonstantin Khlebnikov mm->stack_vm += npages; 3311d977d56cSKonstantin Khlebnikov else if (is_data_mapping(flags)) 331284638335SKonstantin Khlebnikov mm->data_vm += npages; 3313119f657cSakpm@osdl.org } 3314fa5dc22fSRoland McGrath 3315b3ec9f33SSouptick Joarder static vm_fault_t special_mapping_fault(struct vm_fault *vmf); 3316a62c34bdSAndy Lutomirski 3317a62c34bdSAndy Lutomirski /* 3318a62c34bdSAndy Lutomirski * Having a close hook prevents vma merging regardless of flags. 3319a62c34bdSAndy Lutomirski */ 3320a62c34bdSAndy Lutomirski static void special_mapping_close(struct vm_area_struct *vma) 3321a62c34bdSAndy Lutomirski { 3322a62c34bdSAndy Lutomirski } 3323a62c34bdSAndy Lutomirski 3324a62c34bdSAndy Lutomirski static const char *special_mapping_name(struct vm_area_struct *vma) 3325a62c34bdSAndy Lutomirski { 3326a62c34bdSAndy Lutomirski return ((struct vm_special_mapping *)vma->vm_private_data)->name; 3327a62c34bdSAndy Lutomirski } 3328a62c34bdSAndy Lutomirski 332914d07113SBrian Geffon static int special_mapping_mremap(struct vm_area_struct *new_vma) 3330b059a453SDmitry Safonov { 3331b059a453SDmitry Safonov struct vm_special_mapping *sm = new_vma->vm_private_data; 3332b059a453SDmitry Safonov 3333280e87e9SDmitry Safonov if (WARN_ON_ONCE(current->mm != new_vma->vm_mm)) 3334280e87e9SDmitry Safonov return -EFAULT; 3335280e87e9SDmitry Safonov 3336b059a453SDmitry Safonov if (sm->mremap) 3337b059a453SDmitry Safonov return sm->mremap(sm, new_vma); 3338280e87e9SDmitry Safonov 3339b059a453SDmitry Safonov return 0; 3340b059a453SDmitry Safonov } 3341b059a453SDmitry Safonov 3342871402e0SDmitry Safonov static int special_mapping_split(struct vm_area_struct *vma, unsigned long addr) 3343871402e0SDmitry Safonov { 3344871402e0SDmitry Safonov /* 3345871402e0SDmitry Safonov * Forbid splitting special mappings - kernel has expectations over 3346871402e0SDmitry Safonov * the number of pages in mapping. Together with VM_DONTEXPAND 3347871402e0SDmitry Safonov * the size of vma should stay the same over the special mapping's 3348871402e0SDmitry Safonov * lifetime. 3349871402e0SDmitry Safonov */ 3350871402e0SDmitry Safonov return -EINVAL; 3351871402e0SDmitry Safonov } 3352871402e0SDmitry Safonov 3353a62c34bdSAndy Lutomirski static const struct vm_operations_struct special_mapping_vmops = { 3354a62c34bdSAndy Lutomirski .close = special_mapping_close, 3355a62c34bdSAndy Lutomirski .fault = special_mapping_fault, 3356b059a453SDmitry Safonov .mremap = special_mapping_mremap, 3357a62c34bdSAndy Lutomirski .name = special_mapping_name, 3358af34ebebSDmitry Safonov /* vDSO code relies that VVAR can't be accessed remotely */ 3359af34ebebSDmitry Safonov .access = NULL, 3360871402e0SDmitry Safonov .may_split = special_mapping_split, 3361a62c34bdSAndy Lutomirski }; 3362a62c34bdSAndy Lutomirski 3363a62c34bdSAndy Lutomirski static const struct vm_operations_struct legacy_special_mapping_vmops = { 3364a62c34bdSAndy Lutomirski .close = special_mapping_close, 3365a62c34bdSAndy Lutomirski .fault = special_mapping_fault, 3366a62c34bdSAndy Lutomirski }; 3367fa5dc22fSRoland McGrath 3368b3ec9f33SSouptick Joarder static vm_fault_t special_mapping_fault(struct vm_fault *vmf) 3369fa5dc22fSRoland McGrath { 337011bac800SDave Jiang struct vm_area_struct *vma = vmf->vma; 3371b1d0e4f5SNick Piggin pgoff_t pgoff; 3372fa5dc22fSRoland McGrath struct page **pages; 3373fa5dc22fSRoland McGrath 3374f872f540SAndy Lutomirski if (vma->vm_ops == &legacy_special_mapping_vmops) { 3375a62c34bdSAndy Lutomirski pages = vma->vm_private_data; 3376f872f540SAndy Lutomirski } else { 3377f872f540SAndy Lutomirski struct vm_special_mapping *sm = vma->vm_private_data; 3378f872f540SAndy Lutomirski 3379f872f540SAndy Lutomirski if (sm->fault) 338011bac800SDave Jiang return sm->fault(sm, vmf->vma, vmf); 3381f872f540SAndy Lutomirski 3382f872f540SAndy Lutomirski pages = sm->pages; 3383f872f540SAndy Lutomirski } 3384a62c34bdSAndy Lutomirski 33858a9cc3b5SOleg Nesterov for (pgoff = vmf->pgoff; pgoff && *pages; ++pages) 3386b1d0e4f5SNick Piggin pgoff--; 3387fa5dc22fSRoland McGrath 3388fa5dc22fSRoland McGrath if (*pages) { 3389fa5dc22fSRoland McGrath struct page *page = *pages; 3390fa5dc22fSRoland McGrath get_page(page); 3391b1d0e4f5SNick Piggin vmf->page = page; 3392b1d0e4f5SNick Piggin return 0; 3393fa5dc22fSRoland McGrath } 3394fa5dc22fSRoland McGrath 3395b1d0e4f5SNick Piggin return VM_FAULT_SIGBUS; 3396fa5dc22fSRoland McGrath } 3397fa5dc22fSRoland McGrath 3398a62c34bdSAndy Lutomirski static struct vm_area_struct *__install_special_mapping( 3399a62c34bdSAndy Lutomirski struct mm_struct *mm, 3400fa5dc22fSRoland McGrath unsigned long addr, unsigned long len, 340127f28b97SChen Gang unsigned long vm_flags, void *priv, 340227f28b97SChen Gang const struct vm_operations_struct *ops) 3403fa5dc22fSRoland McGrath { 3404462e635eSTavis Ormandy int ret; 3405fa5dc22fSRoland McGrath struct vm_area_struct *vma; 3406fa5dc22fSRoland McGrath 3407d4af56c5SLiam R. Howlett validate_mm_mt(mm); 3408490fc053SLinus Torvalds vma = vm_area_alloc(mm); 3409fa5dc22fSRoland McGrath if (unlikely(vma == NULL)) 34103935ed6aSStefani Seibold return ERR_PTR(-ENOMEM); 3411fa5dc22fSRoland McGrath 3412fa5dc22fSRoland McGrath vma->vm_start = addr; 3413fa5dc22fSRoland McGrath vma->vm_end = addr + len; 3414fa5dc22fSRoland McGrath 3415d9104d1cSCyrill Gorcunov vma->vm_flags = vm_flags | mm->def_flags | VM_DONTEXPAND | VM_SOFTDIRTY; 34161fc09228SHugh Dickins vma->vm_flags &= VM_LOCKED_CLEAR_MASK; 34173ed75eb8SColy Li vma->vm_page_prot = vm_get_page_prot(vma->vm_flags); 3418fa5dc22fSRoland McGrath 3419a62c34bdSAndy Lutomirski vma->vm_ops = ops; 3420a62c34bdSAndy Lutomirski vma->vm_private_data = priv; 3421fa5dc22fSRoland McGrath 3422462e635eSTavis Ormandy ret = insert_vm_struct(mm, vma); 3423462e635eSTavis Ormandy if (ret) 3424462e635eSTavis Ormandy goto out; 3425fa5dc22fSRoland McGrath 342684638335SKonstantin Khlebnikov vm_stat_account(mm, vma->vm_flags, len >> PAGE_SHIFT); 3427fa5dc22fSRoland McGrath 3428cdd6c482SIngo Molnar perf_event_mmap(vma); 3429089dd79dSPeter Zijlstra 3430d4af56c5SLiam R. Howlett validate_mm_mt(mm); 34313935ed6aSStefani Seibold return vma; 3432462e635eSTavis Ormandy 3433462e635eSTavis Ormandy out: 34343928d4f5SLinus Torvalds vm_area_free(vma); 3435d4af56c5SLiam R. Howlett validate_mm_mt(mm); 34363935ed6aSStefani Seibold return ERR_PTR(ret); 34373935ed6aSStefani Seibold } 34383935ed6aSStefani Seibold 34392eefd878SDmitry Safonov bool vma_is_special_mapping(const struct vm_area_struct *vma, 34402eefd878SDmitry Safonov const struct vm_special_mapping *sm) 34412eefd878SDmitry Safonov { 34422eefd878SDmitry Safonov return vma->vm_private_data == sm && 34432eefd878SDmitry Safonov (vma->vm_ops == &special_mapping_vmops || 34442eefd878SDmitry Safonov vma->vm_ops == &legacy_special_mapping_vmops); 34452eefd878SDmitry Safonov } 34462eefd878SDmitry Safonov 3447a62c34bdSAndy Lutomirski /* 3448c1e8d7c6SMichel Lespinasse * Called with mm->mmap_lock held for writing. 3449a62c34bdSAndy Lutomirski * Insert a new vma covering the given region, with the given flags. 3450a62c34bdSAndy Lutomirski * Its pages are supplied by the given array of struct page *. 3451a62c34bdSAndy Lutomirski * The array can be shorter than len >> PAGE_SHIFT if it's null-terminated. 3452a62c34bdSAndy Lutomirski * The region past the last page supplied will always produce SIGBUS. 3453a62c34bdSAndy Lutomirski * The array pointer and the pages it points to are assumed to stay alive 3454a62c34bdSAndy Lutomirski * for as long as this mapping might exist. 3455a62c34bdSAndy Lutomirski */ 3456a62c34bdSAndy Lutomirski struct vm_area_struct *_install_special_mapping( 3457a62c34bdSAndy Lutomirski struct mm_struct *mm, 3458a62c34bdSAndy Lutomirski unsigned long addr, unsigned long len, 3459a62c34bdSAndy Lutomirski unsigned long vm_flags, const struct vm_special_mapping *spec) 3460a62c34bdSAndy Lutomirski { 346127f28b97SChen Gang return __install_special_mapping(mm, addr, len, vm_flags, (void *)spec, 346227f28b97SChen Gang &special_mapping_vmops); 3463a62c34bdSAndy Lutomirski } 3464a62c34bdSAndy Lutomirski 34653935ed6aSStefani Seibold int install_special_mapping(struct mm_struct *mm, 34663935ed6aSStefani Seibold unsigned long addr, unsigned long len, 34673935ed6aSStefani Seibold unsigned long vm_flags, struct page **pages) 34683935ed6aSStefani Seibold { 3469a62c34bdSAndy Lutomirski struct vm_area_struct *vma = __install_special_mapping( 347027f28b97SChen Gang mm, addr, len, vm_flags, (void *)pages, 347127f28b97SChen Gang &legacy_special_mapping_vmops); 34723935ed6aSStefani Seibold 347314bd5b45SDuan Jiong return PTR_ERR_OR_ZERO(vma); 3474fa5dc22fSRoland McGrath } 34757906d00cSAndrea Arcangeli 34767906d00cSAndrea Arcangeli static DEFINE_MUTEX(mm_all_locks_mutex); 34777906d00cSAndrea Arcangeli 3478454ed842SPeter Zijlstra static void vm_lock_anon_vma(struct mm_struct *mm, struct anon_vma *anon_vma) 34797906d00cSAndrea Arcangeli { 3480f808c13fSDavidlohr Bueso if (!test_bit(0, (unsigned long *) &anon_vma->root->rb_root.rb_root.rb_node)) { 34817906d00cSAndrea Arcangeli /* 34827906d00cSAndrea Arcangeli * The LSB of head.next can't change from under us 34837906d00cSAndrea Arcangeli * because we hold the mm_all_locks_mutex. 34847906d00cSAndrea Arcangeli */ 3485da1c55f1SMichel Lespinasse down_write_nest_lock(&anon_vma->root->rwsem, &mm->mmap_lock); 34867906d00cSAndrea Arcangeli /* 34877906d00cSAndrea Arcangeli * We can safely modify head.next after taking the 34885a505085SIngo Molnar * anon_vma->root->rwsem. If some other vma in this mm shares 34897906d00cSAndrea Arcangeli * the same anon_vma we won't take it again. 34907906d00cSAndrea Arcangeli * 34917906d00cSAndrea Arcangeli * No need of atomic instructions here, head.next 34927906d00cSAndrea Arcangeli * can't change from under us thanks to the 34935a505085SIngo Molnar * anon_vma->root->rwsem. 34947906d00cSAndrea Arcangeli */ 34957906d00cSAndrea Arcangeli if (__test_and_set_bit(0, (unsigned long *) 3496f808c13fSDavidlohr Bueso &anon_vma->root->rb_root.rb_root.rb_node)) 34977906d00cSAndrea Arcangeli BUG(); 34987906d00cSAndrea Arcangeli } 34997906d00cSAndrea Arcangeli } 35007906d00cSAndrea Arcangeli 3501454ed842SPeter Zijlstra static void vm_lock_mapping(struct mm_struct *mm, struct address_space *mapping) 35027906d00cSAndrea Arcangeli { 35037906d00cSAndrea Arcangeli if (!test_bit(AS_MM_ALL_LOCKS, &mapping->flags)) { 35047906d00cSAndrea Arcangeli /* 35057906d00cSAndrea Arcangeli * AS_MM_ALL_LOCKS can't change from under us because 35067906d00cSAndrea Arcangeli * we hold the mm_all_locks_mutex. 35077906d00cSAndrea Arcangeli * 35087906d00cSAndrea Arcangeli * Operations on ->flags have to be atomic because 35097906d00cSAndrea Arcangeli * even if AS_MM_ALL_LOCKS is stable thanks to the 35107906d00cSAndrea Arcangeli * mm_all_locks_mutex, there may be other cpus 35117906d00cSAndrea Arcangeli * changing other bitflags in parallel to us. 35127906d00cSAndrea Arcangeli */ 35137906d00cSAndrea Arcangeli if (test_and_set_bit(AS_MM_ALL_LOCKS, &mapping->flags)) 35147906d00cSAndrea Arcangeli BUG(); 3515da1c55f1SMichel Lespinasse down_write_nest_lock(&mapping->i_mmap_rwsem, &mm->mmap_lock); 35167906d00cSAndrea Arcangeli } 35177906d00cSAndrea Arcangeli } 35187906d00cSAndrea Arcangeli 35197906d00cSAndrea Arcangeli /* 35207906d00cSAndrea Arcangeli * This operation locks against the VM for all pte/vma/mm related 35217906d00cSAndrea Arcangeli * operations that could ever happen on a certain mm. This includes 35227906d00cSAndrea Arcangeli * vmtruncate, try_to_unmap, and all page faults. 35237906d00cSAndrea Arcangeli * 3524c1e8d7c6SMichel Lespinasse * The caller must take the mmap_lock in write mode before calling 35257906d00cSAndrea Arcangeli * mm_take_all_locks(). The caller isn't allowed to release the 3526c1e8d7c6SMichel Lespinasse * mmap_lock until mm_drop_all_locks() returns. 35277906d00cSAndrea Arcangeli * 3528c1e8d7c6SMichel Lespinasse * mmap_lock in write mode is required in order to block all operations 35297906d00cSAndrea Arcangeli * that could modify pagetables and free pages without need of 353027ba0644SKirill A. Shutemov * altering the vma layout. It's also needed in write mode to avoid new 35317906d00cSAndrea Arcangeli * anon_vmas to be associated with existing vmas. 35327906d00cSAndrea Arcangeli * 35337906d00cSAndrea Arcangeli * A single task can't take more than one mm_take_all_locks() in a row 35347906d00cSAndrea Arcangeli * or it would deadlock. 35357906d00cSAndrea Arcangeli * 3536bf181b9fSMichel Lespinasse * The LSB in anon_vma->rb_root.rb_node and the AS_MM_ALL_LOCKS bitflag in 35377906d00cSAndrea Arcangeli * mapping->flags avoid to take the same lock twice, if more than one 35387906d00cSAndrea Arcangeli * vma in this mm is backed by the same anon_vma or address_space. 35397906d00cSAndrea Arcangeli * 354088f306b6SKirill A. Shutemov * We take locks in following order, accordingly to comment at beginning 354188f306b6SKirill A. Shutemov * of mm/rmap.c: 354288f306b6SKirill A. Shutemov * - all hugetlbfs_i_mmap_rwsem_key locks (aka mapping->i_mmap_rwsem for 354388f306b6SKirill A. Shutemov * hugetlb mapping); 354488f306b6SKirill A. Shutemov * - all i_mmap_rwsem locks; 354588f306b6SKirill A. Shutemov * - all anon_vma->rwseml 354688f306b6SKirill A. Shutemov * 354788f306b6SKirill A. Shutemov * We can take all locks within these types randomly because the VM code 354888f306b6SKirill A. Shutemov * doesn't nest them and we protected from parallel mm_take_all_locks() by 354988f306b6SKirill A. Shutemov * mm_all_locks_mutex. 35507906d00cSAndrea Arcangeli * 35517906d00cSAndrea Arcangeli * mm_take_all_locks() and mm_drop_all_locks are expensive operations 35527906d00cSAndrea Arcangeli * that may have to take thousand of locks. 35537906d00cSAndrea Arcangeli * 35547906d00cSAndrea Arcangeli * mm_take_all_locks() can fail if it's interrupted by signals. 35557906d00cSAndrea Arcangeli */ 35567906d00cSAndrea Arcangeli int mm_take_all_locks(struct mm_struct *mm) 35577906d00cSAndrea Arcangeli { 35587906d00cSAndrea Arcangeli struct vm_area_struct *vma; 35595beb4930SRik van Riel struct anon_vma_chain *avc; 3560763ecb03SLiam R. Howlett MA_STATE(mas, &mm->mm_mt, 0, 0); 35617906d00cSAndrea Arcangeli 3562325bca1fSRolf Eike Beer mmap_assert_write_locked(mm); 35637906d00cSAndrea Arcangeli 35647906d00cSAndrea Arcangeli mutex_lock(&mm_all_locks_mutex); 35657906d00cSAndrea Arcangeli 3566763ecb03SLiam R. Howlett mas_for_each(&mas, vma, ULONG_MAX) { 35677906d00cSAndrea Arcangeli if (signal_pending(current)) 35687906d00cSAndrea Arcangeli goto out_unlock; 356988f306b6SKirill A. Shutemov if (vma->vm_file && vma->vm_file->f_mapping && 357088f306b6SKirill A. Shutemov is_vm_hugetlb_page(vma)) 357188f306b6SKirill A. Shutemov vm_lock_mapping(mm, vma->vm_file->f_mapping); 357288f306b6SKirill A. Shutemov } 357388f306b6SKirill A. Shutemov 3574763ecb03SLiam R. Howlett mas_set(&mas, 0); 3575763ecb03SLiam R. Howlett mas_for_each(&mas, vma, ULONG_MAX) { 357688f306b6SKirill A. Shutemov if (signal_pending(current)) 357788f306b6SKirill A. Shutemov goto out_unlock; 357888f306b6SKirill A. Shutemov if (vma->vm_file && vma->vm_file->f_mapping && 357988f306b6SKirill A. Shutemov !is_vm_hugetlb_page(vma)) 3580454ed842SPeter Zijlstra vm_lock_mapping(mm, vma->vm_file->f_mapping); 35817906d00cSAndrea Arcangeli } 35827cd5a02fSPeter Zijlstra 3583763ecb03SLiam R. Howlett mas_set(&mas, 0); 3584763ecb03SLiam R. Howlett mas_for_each(&mas, vma, ULONG_MAX) { 35857cd5a02fSPeter Zijlstra if (signal_pending(current)) 35867cd5a02fSPeter Zijlstra goto out_unlock; 35877cd5a02fSPeter Zijlstra if (vma->anon_vma) 35885beb4930SRik van Riel list_for_each_entry(avc, &vma->anon_vma_chain, same_vma) 35895beb4930SRik van Riel vm_lock_anon_vma(mm, avc->anon_vma); 35907cd5a02fSPeter Zijlstra } 35917cd5a02fSPeter Zijlstra 3592584cff54SKautuk Consul return 0; 35937906d00cSAndrea Arcangeli 35947906d00cSAndrea Arcangeli out_unlock: 35957906d00cSAndrea Arcangeli mm_drop_all_locks(mm); 3596584cff54SKautuk Consul return -EINTR; 35977906d00cSAndrea Arcangeli } 35987906d00cSAndrea Arcangeli 35997906d00cSAndrea Arcangeli static void vm_unlock_anon_vma(struct anon_vma *anon_vma) 36007906d00cSAndrea Arcangeli { 3601f808c13fSDavidlohr Bueso if (test_bit(0, (unsigned long *) &anon_vma->root->rb_root.rb_root.rb_node)) { 36027906d00cSAndrea Arcangeli /* 36037906d00cSAndrea Arcangeli * The LSB of head.next can't change to 0 from under 36047906d00cSAndrea Arcangeli * us because we hold the mm_all_locks_mutex. 36057906d00cSAndrea Arcangeli * 36067906d00cSAndrea Arcangeli * We must however clear the bitflag before unlocking 3607bf181b9fSMichel Lespinasse * the vma so the users using the anon_vma->rb_root will 36087906d00cSAndrea Arcangeli * never see our bitflag. 36097906d00cSAndrea Arcangeli * 36107906d00cSAndrea Arcangeli * No need of atomic instructions here, head.next 36117906d00cSAndrea Arcangeli * can't change from under us until we release the 36125a505085SIngo Molnar * anon_vma->root->rwsem. 36137906d00cSAndrea Arcangeli */ 36147906d00cSAndrea Arcangeli if (!__test_and_clear_bit(0, (unsigned long *) 3615f808c13fSDavidlohr Bueso &anon_vma->root->rb_root.rb_root.rb_node)) 36167906d00cSAndrea Arcangeli BUG(); 361708b52706SKonstantin Khlebnikov anon_vma_unlock_write(anon_vma); 36187906d00cSAndrea Arcangeli } 36197906d00cSAndrea Arcangeli } 36207906d00cSAndrea Arcangeli 36217906d00cSAndrea Arcangeli static void vm_unlock_mapping(struct address_space *mapping) 36227906d00cSAndrea Arcangeli { 36237906d00cSAndrea Arcangeli if (test_bit(AS_MM_ALL_LOCKS, &mapping->flags)) { 36247906d00cSAndrea Arcangeli /* 36257906d00cSAndrea Arcangeli * AS_MM_ALL_LOCKS can't change to 0 from under us 36267906d00cSAndrea Arcangeli * because we hold the mm_all_locks_mutex. 36277906d00cSAndrea Arcangeli */ 362883cde9e8SDavidlohr Bueso i_mmap_unlock_write(mapping); 36297906d00cSAndrea Arcangeli if (!test_and_clear_bit(AS_MM_ALL_LOCKS, 36307906d00cSAndrea Arcangeli &mapping->flags)) 36317906d00cSAndrea Arcangeli BUG(); 36327906d00cSAndrea Arcangeli } 36337906d00cSAndrea Arcangeli } 36347906d00cSAndrea Arcangeli 36357906d00cSAndrea Arcangeli /* 3636c1e8d7c6SMichel Lespinasse * The mmap_lock cannot be released by the caller until 36377906d00cSAndrea Arcangeli * mm_drop_all_locks() returns. 36387906d00cSAndrea Arcangeli */ 36397906d00cSAndrea Arcangeli void mm_drop_all_locks(struct mm_struct *mm) 36407906d00cSAndrea Arcangeli { 36417906d00cSAndrea Arcangeli struct vm_area_struct *vma; 36425beb4930SRik van Riel struct anon_vma_chain *avc; 3643763ecb03SLiam R. Howlett MA_STATE(mas, &mm->mm_mt, 0, 0); 36447906d00cSAndrea Arcangeli 3645325bca1fSRolf Eike Beer mmap_assert_write_locked(mm); 36467906d00cSAndrea Arcangeli BUG_ON(!mutex_is_locked(&mm_all_locks_mutex)); 36477906d00cSAndrea Arcangeli 3648763ecb03SLiam R. Howlett mas_for_each(&mas, vma, ULONG_MAX) { 36497906d00cSAndrea Arcangeli if (vma->anon_vma) 36505beb4930SRik van Riel list_for_each_entry(avc, &vma->anon_vma_chain, same_vma) 36515beb4930SRik van Riel vm_unlock_anon_vma(avc->anon_vma); 36527906d00cSAndrea Arcangeli if (vma->vm_file && vma->vm_file->f_mapping) 36537906d00cSAndrea Arcangeli vm_unlock_mapping(vma->vm_file->f_mapping); 36547906d00cSAndrea Arcangeli } 36557906d00cSAndrea Arcangeli 36567906d00cSAndrea Arcangeli mutex_unlock(&mm_all_locks_mutex); 36577906d00cSAndrea Arcangeli } 36588feae131SDavid Howells 36598feae131SDavid Howells /* 36603edf41d8Sseokhoon.yoon * initialise the percpu counter for VM 36618feae131SDavid Howells */ 36628feae131SDavid Howells void __init mmap_init(void) 36638feae131SDavid Howells { 366400a62ce9SKOSAKI Motohiro int ret; 366500a62ce9SKOSAKI Motohiro 3666908c7f19STejun Heo ret = percpu_counter_init(&vm_committed_as, 0, GFP_KERNEL); 366700a62ce9SKOSAKI Motohiro VM_BUG_ON(ret); 36688feae131SDavid Howells } 3669c9b1d098SAndrew Shewmaker 3670c9b1d098SAndrew Shewmaker /* 3671c9b1d098SAndrew Shewmaker * Initialise sysctl_user_reserve_kbytes. 3672c9b1d098SAndrew Shewmaker * 3673c9b1d098SAndrew Shewmaker * This is intended to prevent a user from starting a single memory hogging 3674c9b1d098SAndrew Shewmaker * process, such that they cannot recover (kill the hog) in OVERCOMMIT_NEVER 3675c9b1d098SAndrew Shewmaker * mode. 3676c9b1d098SAndrew Shewmaker * 3677c9b1d098SAndrew Shewmaker * The default value is min(3% of free memory, 128MB) 3678c9b1d098SAndrew Shewmaker * 128MB is enough to recover with sshd/login, bash, and top/kill. 3679c9b1d098SAndrew Shewmaker */ 36801640879aSAndrew Shewmaker static int init_user_reserve(void) 3681c9b1d098SAndrew Shewmaker { 3682c9b1d098SAndrew Shewmaker unsigned long free_kbytes; 3683c9b1d098SAndrew Shewmaker 3684c41f012aSMichal Hocko free_kbytes = global_zone_page_state(NR_FREE_PAGES) << (PAGE_SHIFT - 10); 3685c9b1d098SAndrew Shewmaker 3686c9b1d098SAndrew Shewmaker sysctl_user_reserve_kbytes = min(free_kbytes / 32, 1UL << 17); 3687c9b1d098SAndrew Shewmaker return 0; 3688c9b1d098SAndrew Shewmaker } 3689a64fb3cdSPaul Gortmaker subsys_initcall(init_user_reserve); 36904eeab4f5SAndrew Shewmaker 36914eeab4f5SAndrew Shewmaker /* 36924eeab4f5SAndrew Shewmaker * Initialise sysctl_admin_reserve_kbytes. 36934eeab4f5SAndrew Shewmaker * 36944eeab4f5SAndrew Shewmaker * The purpose of sysctl_admin_reserve_kbytes is to allow the sys admin 36954eeab4f5SAndrew Shewmaker * to log in and kill a memory hogging process. 36964eeab4f5SAndrew Shewmaker * 36974eeab4f5SAndrew Shewmaker * Systems with more than 256MB will reserve 8MB, enough to recover 36984eeab4f5SAndrew Shewmaker * with sshd, bash, and top in OVERCOMMIT_GUESS. Smaller systems will 36994eeab4f5SAndrew Shewmaker * only reserve 3% of free pages by default. 37004eeab4f5SAndrew Shewmaker */ 37011640879aSAndrew Shewmaker static int init_admin_reserve(void) 37024eeab4f5SAndrew Shewmaker { 37034eeab4f5SAndrew Shewmaker unsigned long free_kbytes; 37044eeab4f5SAndrew Shewmaker 3705c41f012aSMichal Hocko free_kbytes = global_zone_page_state(NR_FREE_PAGES) << (PAGE_SHIFT - 10); 37064eeab4f5SAndrew Shewmaker 37074eeab4f5SAndrew Shewmaker sysctl_admin_reserve_kbytes = min(free_kbytes / 32, 1UL << 13); 37084eeab4f5SAndrew Shewmaker return 0; 37094eeab4f5SAndrew Shewmaker } 3710a64fb3cdSPaul Gortmaker subsys_initcall(init_admin_reserve); 37111640879aSAndrew Shewmaker 37121640879aSAndrew Shewmaker /* 37131640879aSAndrew Shewmaker * Reinititalise user and admin reserves if memory is added or removed. 37141640879aSAndrew Shewmaker * 37151640879aSAndrew Shewmaker * The default user reserve max is 128MB, and the default max for the 37161640879aSAndrew Shewmaker * admin reserve is 8MB. These are usually, but not always, enough to 37171640879aSAndrew Shewmaker * enable recovery from a memory hogging process using login/sshd, a shell, 37181640879aSAndrew Shewmaker * and tools like top. It may make sense to increase or even disable the 37191640879aSAndrew Shewmaker * reserve depending on the existence of swap or variations in the recovery 37201640879aSAndrew Shewmaker * tools. So, the admin may have changed them. 37211640879aSAndrew Shewmaker * 37221640879aSAndrew Shewmaker * If memory is added and the reserves have been eliminated or increased above 37231640879aSAndrew Shewmaker * the default max, then we'll trust the admin. 37241640879aSAndrew Shewmaker * 37251640879aSAndrew Shewmaker * If memory is removed and there isn't enough free memory, then we 37261640879aSAndrew Shewmaker * need to reset the reserves. 37271640879aSAndrew Shewmaker * 37281640879aSAndrew Shewmaker * Otherwise keep the reserve set by the admin. 37291640879aSAndrew Shewmaker */ 37301640879aSAndrew Shewmaker static int reserve_mem_notifier(struct notifier_block *nb, 37311640879aSAndrew Shewmaker unsigned long action, void *data) 37321640879aSAndrew Shewmaker { 37331640879aSAndrew Shewmaker unsigned long tmp, free_kbytes; 37341640879aSAndrew Shewmaker 37351640879aSAndrew Shewmaker switch (action) { 37361640879aSAndrew Shewmaker case MEM_ONLINE: 37371640879aSAndrew Shewmaker /* Default max is 128MB. Leave alone if modified by operator. */ 37381640879aSAndrew Shewmaker tmp = sysctl_user_reserve_kbytes; 37391640879aSAndrew Shewmaker if (0 < tmp && tmp < (1UL << 17)) 37401640879aSAndrew Shewmaker init_user_reserve(); 37411640879aSAndrew Shewmaker 37421640879aSAndrew Shewmaker /* Default max is 8MB. Leave alone if modified by operator. */ 37431640879aSAndrew Shewmaker tmp = sysctl_admin_reserve_kbytes; 37441640879aSAndrew Shewmaker if (0 < tmp && tmp < (1UL << 13)) 37451640879aSAndrew Shewmaker init_admin_reserve(); 37461640879aSAndrew Shewmaker 37471640879aSAndrew Shewmaker break; 37481640879aSAndrew Shewmaker case MEM_OFFLINE: 3749c41f012aSMichal Hocko free_kbytes = global_zone_page_state(NR_FREE_PAGES) << (PAGE_SHIFT - 10); 37501640879aSAndrew Shewmaker 37511640879aSAndrew Shewmaker if (sysctl_user_reserve_kbytes > free_kbytes) { 37521640879aSAndrew Shewmaker init_user_reserve(); 37531640879aSAndrew Shewmaker pr_info("vm.user_reserve_kbytes reset to %lu\n", 37541640879aSAndrew Shewmaker sysctl_user_reserve_kbytes); 37551640879aSAndrew Shewmaker } 37561640879aSAndrew Shewmaker 37571640879aSAndrew Shewmaker if (sysctl_admin_reserve_kbytes > free_kbytes) { 37581640879aSAndrew Shewmaker init_admin_reserve(); 37591640879aSAndrew Shewmaker pr_info("vm.admin_reserve_kbytes reset to %lu\n", 37601640879aSAndrew Shewmaker sysctl_admin_reserve_kbytes); 37611640879aSAndrew Shewmaker } 37621640879aSAndrew Shewmaker break; 37631640879aSAndrew Shewmaker default: 37641640879aSAndrew Shewmaker break; 37651640879aSAndrew Shewmaker } 37661640879aSAndrew Shewmaker return NOTIFY_OK; 37671640879aSAndrew Shewmaker } 37681640879aSAndrew Shewmaker 37691640879aSAndrew Shewmaker static struct notifier_block reserve_mem_nb = { 37701640879aSAndrew Shewmaker .notifier_call = reserve_mem_notifier, 37711640879aSAndrew Shewmaker }; 37721640879aSAndrew Shewmaker 37731640879aSAndrew Shewmaker static int __meminit init_reserve_notifier(void) 37741640879aSAndrew Shewmaker { 37751640879aSAndrew Shewmaker if (register_hotmemory_notifier(&reserve_mem_nb)) 3776b1de0d13SMitchel Humpherys pr_err("Failed registering memory add/remove notifier for admin reserve\n"); 37771640879aSAndrew Shewmaker 37781640879aSAndrew Shewmaker return 0; 37791640879aSAndrew Shewmaker } 3780a64fb3cdSPaul Gortmaker subsys_initcall(init_reserve_notifier); 3781