X-Git-Url: http://ftp.safe.ca/?p=safe%2Fjmp%2Flinux-2.6;a=blobdiff_plain;f=mm%2Fmmap.c;h=d9c77b2dbe9d6489cdf5e40e5f5ae0dfc2be2a5a;hp=4275e81e25ba69cf49b777ca2819fb6295d7b084;hb=f653398c86a1c104f0992bd788dd4bb065449be4;hpb=cbfee34520666862f8ff539e580c48958fbb7706 diff --git a/mm/mmap.c b/mm/mmap.c index 4275e81..d9c77b2 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -3,7 +3,7 @@ * * Written by obz. * - * Address space accounting code + * Address space accounting code */ #include @@ -26,16 +26,24 @@ #include #include #include +#include +#include #include #include #include #include +#include "internal.h" + #ifndef arch_mmap_check #define arch_mmap_check(addr, len, flags) (0) #endif +#ifndef arch_rebalance_pgtables +#define arch_rebalance_pgtables(addr, len) (addr) +#endif + static void unmap_region(struct mm_struct *mm, struct vm_area_struct *vma, struct vm_area_struct *prev, unsigned long start, unsigned long end); @@ -68,15 +76,16 @@ pgprot_t protection_map[16] = { pgprot_t vm_get_page_prot(unsigned long vm_flags) { - return protection_map[vm_flags & - (VM_READ|VM_WRITE|VM_EXEC|VM_SHARED)]; + return __pgprot(pgprot_val(protection_map[vm_flags & + (VM_READ|VM_WRITE|VM_EXEC|VM_SHARED)]) | + pgprot_val(arch_vm_get_page_prot(vm_flags))); } EXPORT_SYMBOL(vm_get_page_prot); int sysctl_overcommit_memory = OVERCOMMIT_GUESS; /* heuristic overcommit */ int sysctl_overcommit_ratio = 50; /* default is 50% */ int sysctl_max_map_count __read_mostly = DEFAULT_MAX_MAP_COUNT; -atomic_t vm_committed_space = ATOMIC_INIT(0); +struct percpu_counter vm_committed_as; /* * Check that a process has enough memory to allocate a new virtual @@ -167,13 +176,10 @@ int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin) /* Don't let a single process grow too big: leave 3% of the size of this process for other processes */ - allowed -= mm->total_vm / 32; + if (mm) + allowed -= mm->total_vm / 32; - /* - * cast `allowed' as a signed long because vm_committed_space - * sometimes has a negative value - */ - if (atomic_read(&vm_committed_space) < (long)allowed) + if (percpu_counter_read_positive(&vm_committed_as) < allowed) return 0; error: vm_unacct_memory(pages); @@ -226,22 +232,31 @@ static struct vm_area_struct *remove_vma(struct vm_area_struct *vma) might_sleep(); if (vma->vm_ops && vma->vm_ops->close) vma->vm_ops->close(vma); - if (vma->vm_file) + if (vma->vm_file) { fput(vma->vm_file); - mpol_free(vma_policy(vma)); + if (vma->vm_flags & VM_EXECUTABLE) + removed_exe_file_vma(vma->vm_mm); + } + mpol_put(vma_policy(vma)); kmem_cache_free(vm_area_cachep, vma); return next; } -asmlinkage unsigned long sys_brk(unsigned long brk) +SYSCALL_DEFINE1(brk, unsigned long, brk) { unsigned long rlim, retval; unsigned long newbrk, oldbrk; struct mm_struct *mm = current->mm; + unsigned long min_brk; down_write(&mm->mmap_sem); - if (brk < mm->end_code) +#ifdef CONFIG_COMPAT_BRK + min_brk = mm->end_code; +#else + min_brk = mm->start_brk; +#endif + if (brk < min_brk) goto out; /* @@ -251,7 +266,8 @@ asmlinkage unsigned long sys_brk(unsigned long brk) * not page aligned -Ram Gupta */ rlim = current->signal->rlim[RLIMIT_DATA].rlim_cur; - if (rlim < RLIM_INFINITY && brk - mm->start_data > rlim) + if (rlim < RLIM_INFINITY && (brk - mm->start_brk) + + (mm->end_data - mm->start_data) > rlim) goto out; newbrk = PAGE_ALIGN(brk); @@ -352,7 +368,7 @@ find_vma_prepare(struct mm_struct *mm, unsigned long addr, if (vma_tmp->vm_end > addr) { vma = vma_tmp; if (vma_tmp->vm_start <= addr) - return vma; + break; __rb_link = &__rb_parent->rb_left; } else { rb_prev = __rb_parent; @@ -392,9 +408,9 @@ void __vma_link_rb(struct mm_struct *mm, struct vm_area_struct *vma, rb_insert_color(&vma->vm_rb, &mm->mm_rb); } -static inline void __vma_link_file(struct vm_area_struct *vma) +static void __vma_link_file(struct vm_area_struct *vma) { - struct file * file; + struct file *file; file = vma->vm_file; if (file) { @@ -455,11 +471,10 @@ static void vma_link(struct mm_struct *mm, struct vm_area_struct *vma, * insert vm structure into list and rbtree and anon_vma, * but it has already been inserted into prio_tree earlier. */ -static void -__insert_vm_struct(struct mm_struct * mm, struct vm_area_struct * vma) +static void __insert_vm_struct(struct mm_struct *mm, struct vm_area_struct *vma) { - struct vm_area_struct * __vma, * prev; - struct rb_node ** rb_link, * rb_parent; + struct vm_area_struct *__vma, *prev; + struct rb_node **rb_link, *rb_parent; __vma = find_vma_prepare(mm, vma->vm_start,&prev, &rb_link, &rb_parent); BUG_ON(__vma && __vma->vm_start < vma->vm_end); @@ -554,9 +569,9 @@ again: remove_next = 1 + (end > next->vm_end); /* * When changing only vma->vm_end, we don't really need - * anon_vma lock: but is that case worth optimizing out? + * anon_vma lock. */ - if (vma->anon_vma) + if (vma->anon_vma && (insert || importer || start != vma->vm_start)) anon_vma = vma->anon_vma; if (anon_vma) { spin_lock(&anon_vma->lock); @@ -618,10 +633,13 @@ again: remove_next = 1 + (end > next->vm_end); spin_unlock(&mapping->i_mmap_lock); if (remove_next) { - if (file) + if (file) { fput(file); + if (next->vm_flags & VM_EXECUTABLE) + removed_exe_file_vma(mm); + } mm->map_count--; - mpol_free(vma_policy(next)); + mpol_put(vma_policy(next)); kmem_cache_free(vm_area_cachep, next); /* * In mprotect's case 6 (see comments on vma_merge), @@ -641,12 +659,11 @@ again: remove_next = 1 + (end > next->vm_end); * If the vma has a ->close operation then the driver probably needs to release * per-vma resources, so we don't attempt to merge those. */ -#define VM_SPECIAL (VM_IO | VM_DONTEXPAND | VM_RESERVED | VM_PFNMAP) - static inline int is_mergeable_vma(struct vm_area_struct *vma, struct file *file, unsigned long vm_flags) { - if (vma->vm_flags != vm_flags) + /* VM_CAN_NONLINEAR may get set later by f_op->mmap() */ + if ((vma->vm_flags ^ vm_flags) & ~VM_CAN_NONLINEAR) return 0; if (vma->vm_file != file) return 0; @@ -885,10 +902,10 @@ void vm_stat_account(struct mm_struct *mm, unsigned long flags, #endif /* CONFIG_PROC_FS */ /* - * The caller must hold down_write(current->mm->mmap_sem). + * The caller must hold down_write(¤t->mm->mmap_sem). */ -unsigned long do_mmap_pgoff(struct file * file, unsigned long addr, +unsigned long do_mmap_pgoff(struct file *file, unsigned long addr, unsigned long len, unsigned long prot, unsigned long flags, unsigned long pgoff) { @@ -896,7 +913,6 @@ unsigned long do_mmap_pgoff(struct file * file, unsigned long addr, struct inode *inode; unsigned int vm_flags; int error; - int accountable = 1; unsigned long reqprot = prot; /* @@ -912,13 +928,12 @@ unsigned long do_mmap_pgoff(struct file * file, unsigned long addr, if (!len) return -EINVAL; - error = arch_mmap_check(addr, len, flags); - if (error) - return error; + if (!(flags & MAP_FIXED)) + addr = round_hint_to_min(addr); /* Careful about overflows.. */ len = PAGE_ALIGN(len); - if (!len || len > TASK_SIZE) + if (!len) return -ENOMEM; /* offset overflow? */ @@ -943,11 +958,10 @@ unsigned long do_mmap_pgoff(struct file * file, unsigned long addr, vm_flags = calc_vm_prot_bits(prot) | calc_vm_flag_bits(flags) | mm->def_flags | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC; - if (flags & MAP_LOCKED) { + if (flags & MAP_LOCKED) if (!can_do_mlock()) return -EPERM; - vm_flags |= VM_LOCKED; - } + /* mlock MCL_FUTURE? */ if (vm_flags & VM_LOCKED) { unsigned long locked, lock_limit; @@ -993,8 +1007,6 @@ unsigned long do_mmap_pgoff(struct file * file, unsigned long addr, return -EPERM; vm_flags &= ~VM_MAYEXEC; } - if (is_file_hugepages(file)) - accountable = 0; if (!file->f_op || !file->f_op->mmap) return -ENODEV; @@ -1006,6 +1018,10 @@ unsigned long do_mmap_pgoff(struct file * file, unsigned long addr, } else { switch (flags & MAP_TYPE) { case MAP_SHARED: + /* + * Ignore pgoff. + */ + pgoff = 0; vm_flags |= VM_SHARED | VM_MAYSHARE; break; case MAP_PRIVATE: @@ -1023,8 +1039,7 @@ unsigned long do_mmap_pgoff(struct file * file, unsigned long addr, if (error) return error; - return mmap_region(file, addr, len, flags, vm_flags, pgoff, - accountable); + return mmap_region(file, addr, len, flags, vm_flags, pgoff); } EXPORT_SYMBOL(do_mmap_pgoff); @@ -1048,8 +1063,7 @@ int vma_wants_writenotify(struct vm_area_struct *vma) /* The open routine did something to the protections already? */ if (pgprot_val(vma->vm_page_prot) != - pgprot_val(protection_map[vm_flags & - (VM_READ|VM_WRITE|VM_EXEC|VM_SHARED)])) + pgprot_val(vm_get_page_prot(vm_flags))) return 0; /* Specialty mapping? */ @@ -1061,11 +1075,25 @@ int vma_wants_writenotify(struct vm_area_struct *vma) mapping_cap_account_dirty(vma->vm_file->f_mapping); } +/* + * We account for memory if it's a private writeable mapping, + * not hugepages and VM_NORESERVE wasn't set. + */ +static inline int accountable_mapping(struct file *file, unsigned int vm_flags) +{ + /* + * hugetlb has its own accounting separate from the core VM + * VM_HUGETLB may not be set yet so we cannot check for that flag. + */ + if (file && is_file_hugepages(file)) + return 0; + + return (vm_flags & (VM_NORESERVE | VM_SHARED | VM_WRITE)) == VM_WRITE; +} unsigned long mmap_region(struct file *file, unsigned long addr, unsigned long len, unsigned long flags, - unsigned int vm_flags, unsigned long pgoff, - int accountable) + unsigned int vm_flags, unsigned long pgoff) { struct mm_struct *mm = current->mm; struct vm_area_struct *vma, *prev; @@ -1089,30 +1117,35 @@ munmap_back: if (!may_expand_vm(mm, len >> PAGE_SHIFT)) return -ENOMEM; - if (accountable && (!(flags & MAP_NORESERVE) || - sysctl_overcommit_memory == OVERCOMMIT_NEVER)) { - if (vm_flags & VM_SHARED) { - /* Check memory availability in shmem_file_setup? */ - vm_flags |= VM_ACCOUNT; - } else if (vm_flags & VM_WRITE) { - /* - * Private writable mapping: check memory availability - */ - charged = len >> PAGE_SHIFT; - if (security_vm_enough_memory(charged)) - return -ENOMEM; - vm_flags |= VM_ACCOUNT; - } + /* + * Set 'VM_NORESERVE' if we should not account for the + * memory use of this mapping. + */ + if ((flags & MAP_NORESERVE)) { + /* We honor MAP_NORESERVE if allowed to overcommit */ + if (sysctl_overcommit_memory != OVERCOMMIT_NEVER) + vm_flags |= VM_NORESERVE; + + /* hugetlb applies strict overcommit unless MAP_NORESERVE */ + if (file && is_file_hugepages(file)) + vm_flags |= VM_NORESERVE; } /* - * Can we just expand an old private anonymous mapping? - * The VM_SHARED test is necessary because shmem_zero_setup - * will create the file object for a shared anonymous map below. + * Private writable mapping: check memory availability */ - if (!file && !(vm_flags & VM_SHARED) && - vma_merge(mm, prev, addr, addr + len, vm_flags, - NULL, NULL, pgoff, NULL)) + if (accountable_mapping(file, vm_flags)) { + charged = len >> PAGE_SHIFT; + if (security_vm_enough_memory(charged)) + return -ENOMEM; + vm_flags |= VM_ACCOUNT; + } + + /* + * Can we just expand an old mapping? + */ + vma = vma_merge(mm, prev, addr, addr + len, vm_flags, NULL, file, pgoff, NULL); + if (vma) goto out; /* @@ -1130,8 +1163,7 @@ munmap_back: vma->vm_start = addr; vma->vm_end = addr + len; vma->vm_flags = vm_flags; - vma->vm_page_prot = protection_map[vm_flags & - (VM_READ|VM_WRITE|VM_EXEC|VM_SHARED)]; + vma->vm_page_prot = vm_get_page_prot(vm_flags); vma->vm_pgoff = pgoff; if (file) { @@ -1149,56 +1181,58 @@ munmap_back: error = file->f_op->mmap(file, vma); if (error) goto unmap_and_free_vma; + if (vm_flags & VM_EXECUTABLE) + added_exe_file_vma(mm); + + /* Can addr have changed?? + * + * Answer: Yes, several device drivers can do it in their + * f_op->mmap method. -DaveM + */ + addr = vma->vm_start; + pgoff = vma->vm_pgoff; + vm_flags = vma->vm_flags; } else if (vm_flags & VM_SHARED) { error = shmem_zero_setup(vma); if (error) goto free_vma; } - /* We set VM_ACCOUNT in a shared mapping's vm_flags, to inform - * shmem_zero_setup (perhaps called through /dev/zero's ->mmap) - * that memory reservation must be checked; but that reservation - * belongs to shared memory object, not to vma: so now clear it. - */ - if ((vm_flags & (VM_SHARED|VM_ACCOUNT)) == (VM_SHARED|VM_ACCOUNT)) - vma->vm_flags &= ~VM_ACCOUNT; + if (vma_wants_writenotify(vma)) { + pgprot_t pprot = vma->vm_page_prot; - /* Can addr have changed?? - * - * Answer: Yes, several device drivers can do it in their - * f_op->mmap method. -DaveM - */ - addr = vma->vm_start; - pgoff = vma->vm_pgoff; - vm_flags = vma->vm_flags; - - if (vma_wants_writenotify(vma)) - vma->vm_page_prot = - protection_map[vm_flags & (VM_READ|VM_WRITE|VM_EXEC)]; - - if (!file || !vma_merge(mm, prev, addr, vma->vm_end, - vma->vm_flags, NULL, file, pgoff, vma_policy(vma))) { - file = vma->vm_file; - vma_link(mm, vma, prev, rb_link, rb_parent); - if (correct_wcount) - atomic_inc(&inode->i_writecount); - } else { - if (file) { - if (correct_wcount) - atomic_inc(&inode->i_writecount); - fput(file); - } - mpol_free(vma_policy(vma)); - kmem_cache_free(vm_area_cachep, vma); + /* Can vma->vm_page_prot have changed?? + * + * Answer: Yes, drivers may have changed it in their + * f_op->mmap method. + * + * Ensures that vmas marked as uncached stay that way. + */ + vma->vm_page_prot = vm_get_page_prot(vm_flags & ~VM_SHARED); + if (pgprot_val(pprot) == pgprot_val(pgprot_noncached(pprot))) + vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot); } -out: + + vma_link(mm, vma, prev, rb_link, rb_parent); + file = vma->vm_file; + + /* Once vma denies write, undo our temporary denial count */ + if (correct_wcount) + atomic_inc(&inode->i_writecount); +out: + perf_event_mmap(vma); + mm->total_vm += len >> PAGE_SHIFT; vm_stat_account(mm, vm_flags, file, len >> PAGE_SHIFT); if (vm_flags & VM_LOCKED) { - mm->locked_vm += len >> PAGE_SHIFT; - make_pages_present(addr, addr + len); - } - if ((flags & MAP_POPULATE) && !(flags & MAP_NONBLOCK)) + /* + * makes pages present; downgrades, drops, reacquires mmap_sem + */ + long nr_pages = mlock_vma_pages_range(vma, addr, addr + len); + if (nr_pages < 0) + return nr_pages; /* vma gone! */ + mm->locked_vm += (len >> PAGE_SHIFT) - nr_pages; + } else if ((flags & MAP_POPULATE) && !(flags & MAP_NONBLOCK)) make_pages_present(addr, addr + len); return addr; @@ -1411,6 +1445,14 @@ get_unmapped_area(struct file *file, unsigned long addr, unsigned long len, unsigned long (*get_area)(struct file *, unsigned long, unsigned long, unsigned long, unsigned long); + unsigned long error = arch_mmap_check(addr, len, flags); + if (error) + return error; + + /* Careful about overflows.. */ + if (len > TASK_SIZE) + return -ENOMEM; + get_area = current->mm->get_unmapped_area; if (file && file->f_op && file->f_op->get_unmapped_area) get_area = file->f_op->get_unmapped_area; @@ -1423,13 +1465,13 @@ get_unmapped_area(struct file *file, unsigned long addr, unsigned long len, if (addr & ~PAGE_MASK) return -EINVAL; - return addr; + return arch_rebalance_pgtables(addr, len); } EXPORT_SYMBOL(get_unmapped_area); /* Look up the first VMA which satisfies addr < vm_end, NULL if none. */ -struct vm_area_struct * find_vma(struct mm_struct * mm, unsigned long addr) +struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr) { struct vm_area_struct *vma = NULL; @@ -1472,7 +1514,7 @@ find_vma_prev(struct mm_struct *mm, unsigned long addr, struct vm_area_struct **pprev) { struct vm_area_struct *vma = NULL, *prev = NULL; - struct rb_node * rb_node; + struct rb_node *rb_node; if (!mm) goto out; @@ -1506,7 +1548,7 @@ out: * update accounting. This is shared with both the * grow-up and grow-down cases. */ -static int acct_stack_growth(struct vm_area_struct * vma, unsigned long size, unsigned long grow) +static int acct_stack_growth(struct vm_area_struct *vma, unsigned long size, unsigned long grow) { struct mm_struct *mm = vma->vm_mm; struct rlimit *rlim = current->signal->rlim; @@ -1540,7 +1582,7 @@ static int acct_stack_growth(struct vm_area_struct * vma, unsigned long size, un * Overcommit.. This must be the final test, as it will * update security statistics. */ - if (security_vm_enough_memory(grow)) + if (security_vm_enough_memory_mm(mm, grow)) return -ENOMEM; /* Ok, everything looks good - let it rip */ @@ -1557,7 +1599,7 @@ static int acct_stack_growth(struct vm_area_struct * vma, unsigned long size, un * vma is the last one with address > vma->vm_end. Have to extend vma. */ #ifndef CONFIG_IA64 -static inline +static #endif int expand_upwards(struct vm_area_struct *vma, unsigned long address) { @@ -1607,7 +1649,7 @@ int expand_upwards(struct vm_area_struct *vma, unsigned long address) /* * vma is the first one with address < vma->vm_start. Have to extend vma. */ -static inline int expand_downwards(struct vm_area_struct *vma, +static int expand_downwards(struct vm_area_struct *vma, unsigned long address) { int error; @@ -1618,6 +1660,12 @@ static inline int expand_downwards(struct vm_area_struct *vma, */ if (unlikely(anon_vma_prepare(vma))) return -ENOMEM; + + address &= PAGE_MASK; + error = security_file_mmap(NULL, 0, 0, 0, address, 1); + if (error) + return error; + anon_vma_lock(vma); /* @@ -1625,8 +1673,6 @@ static inline int expand_downwards(struct vm_area_struct *vma, * is required to hold the mmap_sem in read mode. We need the * anon_vma lock to serialize against concurrent expand_stacks. */ - address &= PAGE_MASK; - error = 0; /* Somebody else might have raced and expanded it already */ if (address < vma->vm_start) { @@ -1667,8 +1713,10 @@ find_extend_vma(struct mm_struct *mm, unsigned long addr) return vma; if (!prev || expand_stack(prev, addr)) return NULL; - if (prev->vm_flags & VM_LOCKED) - make_pages_present(addr, prev->vm_end); + if (prev->vm_flags & VM_LOCKED) { + if (mlock_vma_pages_range(prev, addr, prev->vm_end) < 0) + return NULL; /* vma gone! */ + } return prev; } #else @@ -1694,8 +1742,10 @@ find_extend_vma(struct mm_struct * mm, unsigned long addr) start = vma->vm_start; if (expand_stack(vma, addr)) return NULL; - if (vma->vm_flags & VM_LOCKED) - make_pages_present(addr, start); + if (vma->vm_flags & VM_LOCKED) { + if (mlock_vma_pages_range(vma, addr, start) < 0) + return NULL; /* vma gone! */ + } return vma; } #endif @@ -1714,8 +1764,6 @@ static void remove_vma_list(struct mm_struct *mm, struct vm_area_struct *vma) long nrpages = vma_pages(vma); mm->total_vm -= nrpages; - if (vma->vm_flags & VM_LOCKED) - mm->locked_vm -= nrpages; vm_stat_account(mm, vma->vm_flags, vma->vm_file, -nrpages); vma = remove_vma(vma); } while (vma); @@ -1740,7 +1788,7 @@ static void unmap_region(struct mm_struct *mm, update_hiwater_rss(mm); unmap_vmas(&tlb, vma, start, end, &nr_accounted, NULL); vm_unacct_memory(nr_accounted); - free_pgtables(&tlb, vma, prev? prev->vm_end: FIRST_USER_ADDRESS, + free_pgtables(tlb, vma, prev? prev->vm_end: FIRST_USER_ADDRESS, next? next->vm_start: 0); tlb_finish_mmu(tlb, start, end); } @@ -1775,21 +1823,19 @@ detach_vmas_to_be_unmapped(struct mm_struct *mm, struct vm_area_struct *vma, } /* - * Split a vma into two pieces at address 'addr', a new vma is allocated - * either for the first part or the tail. + * __split_vma() bypasses sysctl_max_map_count checking. We use this on the + * munmap path where it doesn't make sense to fail. */ -int split_vma(struct mm_struct * mm, struct vm_area_struct * vma, +static int __split_vma(struct mm_struct * mm, struct vm_area_struct * vma, unsigned long addr, int new_below) { struct mempolicy *pol; struct vm_area_struct *new; - if (is_vm_hugetlb_page(vma) && (addr & ~HPAGE_MASK)) + if (is_vm_hugetlb_page(vma) && (addr & + ~(huge_page_mask(hstate_vma(vma))))) return -EINVAL; - if (mm->map_count >= sysctl_max_map_count) - return -ENOMEM; - new = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL); if (!new) return -ENOMEM; @@ -1804,15 +1850,18 @@ int split_vma(struct mm_struct * mm, struct vm_area_struct * vma, new->vm_pgoff += ((addr - vma->vm_start) >> PAGE_SHIFT); } - pol = mpol_copy(vma_policy(vma)); + pol = mpol_dup(vma_policy(vma)); if (IS_ERR(pol)) { kmem_cache_free(vm_area_cachep, new); return PTR_ERR(pol); } vma_set_policy(new, pol); - if (new->vm_file) + if (new->vm_file) { get_file(new->vm_file); + if (vma->vm_flags & VM_EXECUTABLE) + added_exe_file_vma(mm); + } if (new->vm_ops && new->vm_ops->open) new->vm_ops->open(new); @@ -1826,6 +1875,19 @@ int split_vma(struct mm_struct * mm, struct vm_area_struct * vma, return 0; } +/* + * Split a vma into two pieces at address 'addr', a new vma is allocated + * either for the first part or the tail. + */ +int split_vma(struct mm_struct *mm, struct vm_area_struct *vma, + unsigned long addr, int new_below) +{ + if (mm->map_count >= sysctl_max_map_count) + return -ENOMEM; + + return __split_vma(mm, vma, addr, new_below); +} + /* Munmap is split into 2 main parts -- this part which finds * what needs doing, and the areas themselves, which do the * work. This now handles partial unmappings. @@ -1861,7 +1923,17 @@ int do_munmap(struct mm_struct *mm, unsigned long start, size_t len) * places tmp vma above, and higher split_vma places tmp vma below. */ if (start > vma->vm_start) { - int error = split_vma(mm, vma, start, 0); + int error; + + /* + * Make sure that map_count on return from munmap() will + * not exceed its limit; but let map_count go just above + * its limit temporarily, to help free resources as expected. + */ + if (end < vma->vm_end && mm->map_count >= sysctl_max_map_count) + return -ENOMEM; + + error = __split_vma(mm, vma, start, 0); if (error) return error; prev = vma; @@ -1870,13 +1942,27 @@ int do_munmap(struct mm_struct *mm, unsigned long start, size_t len) /* Does it split the last one? */ last = find_vma(mm, end); if (last && end > last->vm_start) { - int error = split_vma(mm, last, end, 1); + int error = __split_vma(mm, last, end, 1); if (error) return error; } vma = prev? prev->vm_next: mm->mmap; /* + * unlock any mlock()ed ranges before detaching vmas + */ + if (mm->locked_vm) { + struct vm_area_struct *tmp = vma; + while (tmp && tmp->vm_start < end) { + if (tmp->vm_flags & VM_LOCKED) { + mm->locked_vm -= vma_pages(tmp); + munlock_vma_pages_all(tmp); + } + tmp = tmp->vm_next; + } + } + + /* * Remove the vma's, and unmap the actual pages */ detach_vmas_to_be_unmapped(mm, vma, prev, end); @@ -1890,7 +1976,7 @@ int do_munmap(struct mm_struct *mm, unsigned long start, size_t len) EXPORT_SYMBOL(do_munmap); -asmlinkage long sys_munmap(unsigned long addr, size_t len) +SYSCALL_DEFINE2(munmap, unsigned long, addr, size_t, len) { int ret; struct mm_struct *mm = current->mm; @@ -1931,16 +2017,14 @@ unsigned long do_brk(unsigned long addr, unsigned long len) if (!len) return addr; - if ((addr + len) > TASK_SIZE || (addr + len) < addr) - return -EINVAL; - - if (is_hugepage_only_range(mm, addr, len)) - return -EINVAL; + error = security_file_mmap(NULL, 0, 0, 0, addr, 1); + if (error) + return error; flags = VM_DATA_DEFAULT_FLAGS | VM_ACCOUNT | mm->def_flags; - error = arch_mmap_check(addr, len, flags); - if (error) + error = get_unmapped_area(NULL, addr, len, 0, MAP_FIXED); + if (error & ~PAGE_MASK) return error; /* @@ -1984,8 +2068,9 @@ unsigned long do_brk(unsigned long addr, unsigned long len) return -ENOMEM; /* Can we just expand an old private anonymous mapping? */ - if (vma_merge(mm, prev, addr, addr + len, flags, - NULL, NULL, pgoff, NULL)) + vma = vma_merge(mm, prev, addr, addr + len, flags, + NULL, NULL, pgoff, NULL); + if (vma) goto out; /* @@ -2002,14 +2087,13 @@ unsigned long do_brk(unsigned long addr, unsigned long len) vma->vm_end = addr + len; vma->vm_pgoff = pgoff; vma->vm_flags = flags; - vma->vm_page_prot = protection_map[flags & - (VM_READ|VM_WRITE|VM_EXEC|VM_SHARED)]; + vma->vm_page_prot = vm_get_page_prot(flags); vma_link(mm, vma, prev, rb_link, rb_parent); out: mm->total_vm += len >> PAGE_SHIFT; if (flags & VM_LOCKED) { - mm->locked_vm += len >> PAGE_SHIFT; - make_pages_present(addr, addr + len); + if (!mlock_vma_pages_range(vma, addr, addr + len)) + mm->locked_vm += (len >> PAGE_SHIFT); } return addr; } @@ -2020,21 +2104,37 @@ EXPORT_SYMBOL(do_brk); void exit_mmap(struct mm_struct *mm) { struct mmu_gather *tlb; - struct vm_area_struct *vma = mm->mmap; + struct vm_area_struct *vma; unsigned long nr_accounted = 0; unsigned long end; /* mm's last user has gone, and its about to be pulled down */ + mmu_notifier_release(mm); + + if (mm->locked_vm) { + vma = mm->mmap; + while (vma) { + if (vma->vm_flags & VM_LOCKED) + munlock_vma_pages_all(vma); + vma = vma->vm_next; + } + } + arch_exit_mmap(mm); + vma = mm->mmap; + if (!vma) /* Can happen if dup_mmap() received an OOM */ + return; + lru_add_drain(); flush_cache_mm(mm); tlb = tlb_gather_mmu(mm, 1); - /* Don't update_hiwater_rss(mm) here, do_exit already did */ + /* update_hiwater_rss(mm) here? but nobody should be looking */ /* Use -1 here to ensure all VMAs in the mm are unmapped */ end = unmap_vmas(&tlb, vma, 0, -1, &nr_accounted, NULL); vm_unacct_memory(nr_accounted); - free_pgtables(&tlb, vma, FIRST_USER_ADDRESS, 0); + + free_pgtables(tlb, vma, FIRST_USER_ADDRESS, 0); tlb_finish_mmu(tlb, 0, end); /* @@ -2117,7 +2217,7 @@ struct vm_area_struct *copy_vma(struct vm_area_struct **vmap, new_vma = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL); if (new_vma) { *new_vma = *vma; - pol = mpol_copy(vma_policy(vma)); + pol = mpol_dup(vma_policy(vma)); if (IS_ERR(pol)) { kmem_cache_free(vm_area_cachep, new_vma); return NULL; @@ -2126,8 +2226,11 @@ struct vm_area_struct *copy_vma(struct vm_area_struct **vmap, new_vma->vm_start = addr; new_vma->vm_end = addr + len; new_vma->vm_pgoff = pgoff; - if (new_vma->vm_file) + if (new_vma->vm_file) { get_file(new_vma->vm_file); + if (vma->vm_flags & VM_EXECUTABLE) + added_exe_file_vma(mm); + } if (new_vma->vm_ops && new_vma->vm_ops->open) new_vma->vm_ops->open(new_vma); vma_link(mm, new_vma, prev, rb_link, rb_parent); @@ -2153,24 +2256,31 @@ int may_expand_vm(struct mm_struct *mm, unsigned long npages) } -static struct page *special_mapping_nopage(struct vm_area_struct *vma, - unsigned long address, int *type) +static int special_mapping_fault(struct vm_area_struct *vma, + struct vm_fault *vmf) { + pgoff_t pgoff; struct page **pages; - BUG_ON(address < vma->vm_start || address >= vma->vm_end); + /* + * special mappings have no vm_file, and in that case, the mm + * uses vm_pgoff internally. So we have to subtract it from here. + * We are allowed to do this because we are the mm; do not copy + * this code into drivers! + */ + pgoff = vmf->pgoff - vma->vm_pgoff; - address -= vma->vm_start; - for (pages = vma->vm_private_data; address > 0 && *pages; ++pages) - address -= PAGE_SIZE; + for (pages = vma->vm_private_data; pgoff && *pages; ++pages) + pgoff--; if (*pages) { struct page *page = *pages; get_page(page); - return page; + vmf->page = page; + return 0; } - return NOPAGE_SIGBUS; + return VM_FAULT_SIGBUS; } /* @@ -2180,9 +2290,9 @@ static void special_mapping_close(struct vm_area_struct *vma) { } -static struct vm_operations_struct special_mapping_vmops = { +static const struct vm_operations_struct special_mapping_vmops = { .close = special_mapping_close, - .nopage = special_mapping_nopage, + .fault = special_mapping_fault, }; /* @@ -2208,8 +2318,8 @@ int install_special_mapping(struct mm_struct *mm, vma->vm_start = addr; vma->vm_end = addr + len; - vma->vm_flags = vm_flags | mm->def_flags; - vma->vm_page_prot = protection_map[vma->vm_flags & 7]; + vma->vm_flags = vm_flags | mm->def_flags | VM_DONTEXPAND; + vma->vm_page_prot = vm_get_page_prot(vma->vm_flags); vma->vm_ops = &special_mapping_vmops; vma->vm_private_data = pages; @@ -2221,5 +2331,182 @@ int install_special_mapping(struct mm_struct *mm, mm->total_vm += len >> PAGE_SHIFT; + perf_event_mmap(vma); + return 0; } + +static DEFINE_MUTEX(mm_all_locks_mutex); + +static void vm_lock_anon_vma(struct mm_struct *mm, struct anon_vma *anon_vma) +{ + if (!test_bit(0, (unsigned long *) &anon_vma->head.next)) { + /* + * The LSB of head.next can't change from under us + * because we hold the mm_all_locks_mutex. + */ + spin_lock_nest_lock(&anon_vma->lock, &mm->mmap_sem); + /* + * We can safely modify head.next after taking the + * anon_vma->lock. If some other vma in this mm shares + * the same anon_vma we won't take it again. + * + * No need of atomic instructions here, head.next + * can't change from under us thanks to the + * anon_vma->lock. + */ + if (__test_and_set_bit(0, (unsigned long *) + &anon_vma->head.next)) + BUG(); + } +} + +static void vm_lock_mapping(struct mm_struct *mm, struct address_space *mapping) +{ + if (!test_bit(AS_MM_ALL_LOCKS, &mapping->flags)) { + /* + * AS_MM_ALL_LOCKS can't change from under us because + * we hold the mm_all_locks_mutex. + * + * Operations on ->flags have to be atomic because + * even if AS_MM_ALL_LOCKS is stable thanks to the + * mm_all_locks_mutex, there may be other cpus + * changing other bitflags in parallel to us. + */ + if (test_and_set_bit(AS_MM_ALL_LOCKS, &mapping->flags)) + BUG(); + spin_lock_nest_lock(&mapping->i_mmap_lock, &mm->mmap_sem); + } +} + +/* + * This operation locks against the VM for all pte/vma/mm related + * operations that could ever happen on a certain mm. This includes + * vmtruncate, try_to_unmap, and all page faults. + * + * The caller must take the mmap_sem in write mode before calling + * mm_take_all_locks(). The caller isn't allowed to release the + * mmap_sem until mm_drop_all_locks() returns. + * + * mmap_sem in write mode is required in order to block all operations + * that could modify pagetables and free pages without need of + * altering the vma layout (for example populate_range() with + * nonlinear vmas). It's also needed in write mode to avoid new + * anon_vmas to be associated with existing vmas. + * + * A single task can't take more than one mm_take_all_locks() in a row + * or it would deadlock. + * + * The LSB in anon_vma->head.next and the AS_MM_ALL_LOCKS bitflag in + * mapping->flags avoid to take the same lock twice, if more than one + * vma in this mm is backed by the same anon_vma or address_space. + * + * We can take all the locks in random order because the VM code + * taking i_mmap_lock or anon_vma->lock outside the mmap_sem never + * takes more than one of them in a row. Secondly we're protected + * against a concurrent mm_take_all_locks() by the mm_all_locks_mutex. + * + * mm_take_all_locks() and mm_drop_all_locks are expensive operations + * that may have to take thousand of locks. + * + * mm_take_all_locks() can fail if it's interrupted by signals. + */ +int mm_take_all_locks(struct mm_struct *mm) +{ + struct vm_area_struct *vma; + int ret = -EINTR; + + BUG_ON(down_read_trylock(&mm->mmap_sem)); + + mutex_lock(&mm_all_locks_mutex); + + for (vma = mm->mmap; vma; vma = vma->vm_next) { + if (signal_pending(current)) + goto out_unlock; + if (vma->vm_file && vma->vm_file->f_mapping) + vm_lock_mapping(mm, vma->vm_file->f_mapping); + } + + for (vma = mm->mmap; vma; vma = vma->vm_next) { + if (signal_pending(current)) + goto out_unlock; + if (vma->anon_vma) + vm_lock_anon_vma(mm, vma->anon_vma); + } + + ret = 0; + +out_unlock: + if (ret) + mm_drop_all_locks(mm); + + return ret; +} + +static void vm_unlock_anon_vma(struct anon_vma *anon_vma) +{ + if (test_bit(0, (unsigned long *) &anon_vma->head.next)) { + /* + * The LSB of head.next can't change to 0 from under + * us because we hold the mm_all_locks_mutex. + * + * We must however clear the bitflag before unlocking + * the vma so the users using the anon_vma->head will + * never see our bitflag. + * + * No need of atomic instructions here, head.next + * can't change from under us until we release the + * anon_vma->lock. + */ + if (!__test_and_clear_bit(0, (unsigned long *) + &anon_vma->head.next)) + BUG(); + spin_unlock(&anon_vma->lock); + } +} + +static void vm_unlock_mapping(struct address_space *mapping) +{ + if (test_bit(AS_MM_ALL_LOCKS, &mapping->flags)) { + /* + * AS_MM_ALL_LOCKS can't change to 0 from under us + * because we hold the mm_all_locks_mutex. + */ + spin_unlock(&mapping->i_mmap_lock); + if (!test_and_clear_bit(AS_MM_ALL_LOCKS, + &mapping->flags)) + BUG(); + } +} + +/* + * The mmap_sem cannot be released by the caller until + * mm_drop_all_locks() returns. + */ +void mm_drop_all_locks(struct mm_struct *mm) +{ + struct vm_area_struct *vma; + + BUG_ON(down_read_trylock(&mm->mmap_sem)); + BUG_ON(!mutex_is_locked(&mm_all_locks_mutex)); + + for (vma = mm->mmap; vma; vma = vma->vm_next) { + if (vma->anon_vma) + vm_unlock_anon_vma(vma->anon_vma); + if (vma->vm_file && vma->vm_file->f_mapping) + vm_unlock_mapping(vma->vm_file->f_mapping); + } + + mutex_unlock(&mm_all_locks_mutex); +} + +/* + * initialise the VMA slab + */ +void __init mmap_init(void) +{ + int ret; + + ret = percpu_counter_init(&vm_committed_as, 0); + VM_BUG_ON(ret); +}