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mm/util.c
22.6 KB
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// SPDX-License-Identifier: GPL-2.0-only |
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#include <linux/mm.h> |
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#include <linux/slab.h> #include <linux/string.h> |
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#include <linux/compiler.h> |
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#include <linux/export.h> |
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#include <linux/err.h> |
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#include <linux/sched.h> |
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#include <linux/sched/mm.h> |
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#include <linux/sched/signal.h> |
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#include <linux/sched/task_stack.h> |
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#include <linux/security.h> |
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#include <linux/swap.h> |
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#include <linux/swapops.h> |
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#include <linux/mman.h> #include <linux/hugetlb.h> |
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#include <linux/vmalloc.h> |
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#include <linux/userfaultfd_k.h> |
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#include <linux/elf.h> |
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#include <linux/elf-randomize.h> #include <linux/personality.h> |
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#include <linux/random.h> |
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#include <linux/processor.h> #include <linux/sizes.h> #include <linux/compat.h> |
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|
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#include <linux/uaccess.h> |
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|
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#include "internal.h" |
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/** * kfree_const - conditionally free memory * @x: pointer to the memory * * Function calls kfree only if @x is not in .rodata section. */ void kfree_const(const void *x) { if (!is_kernel_rodata((unsigned long)x)) kfree(x); } EXPORT_SYMBOL(kfree_const); |
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/** |
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* kstrdup - allocate space for and copy an existing string |
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* @s: the string to duplicate * @gfp: the GFP mask used in the kmalloc() call when allocating memory |
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* * Return: newly allocated copy of @s or %NULL in case of error |
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*/ char *kstrdup(const char *s, gfp_t gfp) { size_t len; char *buf; if (!s) return NULL; len = strlen(s) + 1; |
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buf = kmalloc_track_caller(len, gfp); |
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if (buf) memcpy(buf, s, len); return buf; } EXPORT_SYMBOL(kstrdup); |
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|
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/** |
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* kstrdup_const - conditionally duplicate an existing const string * @s: the string to duplicate * @gfp: the GFP mask used in the kmalloc() call when allocating memory * |
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* Note: Strings allocated by kstrdup_const should be freed by kfree_const. * * Return: source string if it is in .rodata section otherwise * fallback to kstrdup. |
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*/ const char *kstrdup_const(const char *s, gfp_t gfp) { if (is_kernel_rodata((unsigned long)s)) return s; return kstrdup(s, gfp); } EXPORT_SYMBOL(kstrdup_const); /** |
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* kstrndup - allocate space for and copy an existing string * @s: the string to duplicate * @max: read at most @max chars from @s * @gfp: the GFP mask used in the kmalloc() call when allocating memory |
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* * Note: Use kmemdup_nul() instead if the size is known exactly. |
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* * Return: newly allocated copy of @s or %NULL in case of error |
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*/ char *kstrndup(const char *s, size_t max, gfp_t gfp) { size_t len; char *buf; if (!s) return NULL; len = strnlen(s, max); buf = kmalloc_track_caller(len+1, gfp); if (buf) { memcpy(buf, s, len); buf[len] = '\0'; } return buf; } EXPORT_SYMBOL(kstrndup); /** |
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* kmemdup - duplicate region of memory * * @src: memory region to duplicate * @len: memory region length * @gfp: GFP mask to use |
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* * Return: newly allocated copy of @src or %NULL in case of error |
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*/ void *kmemdup(const void *src, size_t len, gfp_t gfp) { void *p; |
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p = kmalloc_track_caller(len, gfp); |
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if (p) memcpy(p, src, len); return p; } EXPORT_SYMBOL(kmemdup); |
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/** |
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* kmemdup_nul - Create a NUL-terminated string from unterminated data * @s: The data to stringify * @len: The size of the data * @gfp: the GFP mask used in the kmalloc() call when allocating memory |
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* * Return: newly allocated copy of @s with NUL-termination or %NULL in * case of error |
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*/ char *kmemdup_nul(const char *s, size_t len, gfp_t gfp) { char *buf; if (!s) return NULL; buf = kmalloc_track_caller(len + 1, gfp); if (buf) { memcpy(buf, s, len); buf[len] = '\0'; } return buf; } EXPORT_SYMBOL(kmemdup_nul); /** |
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* memdup_user - duplicate memory region from user space * * @src: source address in user space * @len: number of bytes to copy * |
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* Return: an ERR_PTR() on failure. Result is physically |
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* contiguous, to be freed by kfree(). |
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*/ void *memdup_user(const void __user *src, size_t len) { void *p; |
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p = kmalloc_track_caller(len, GFP_USER | __GFP_NOWARN); |
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if (!p) return ERR_PTR(-ENOMEM); if (copy_from_user(p, src, len)) { kfree(p); return ERR_PTR(-EFAULT); } return p; } EXPORT_SYMBOL(memdup_user); |
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/** * vmemdup_user - duplicate memory region from user space * * @src: source address in user space * @len: number of bytes to copy * |
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* Return: an ERR_PTR() on failure. Result may be not |
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* physically contiguous. Use kvfree() to free. */ void *vmemdup_user(const void __user *src, size_t len) { void *p; p = kvmalloc(len, GFP_USER); if (!p) return ERR_PTR(-ENOMEM); if (copy_from_user(p, src, len)) { kvfree(p); return ERR_PTR(-EFAULT); } return p; } EXPORT_SYMBOL(vmemdup_user); |
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/** |
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* strndup_user - duplicate an existing string from user space |
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* @s: The string to duplicate * @n: Maximum number of bytes to copy, including the trailing NUL. |
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* |
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* Return: newly allocated copy of @s or an ERR_PTR() in case of error |
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*/ char *strndup_user(const char __user *s, long n) { char *p; long length; length = strnlen_user(s, n); if (!length) return ERR_PTR(-EFAULT); if (length > n) return ERR_PTR(-EINVAL); |
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p = memdup_user(s, length); |
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|
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if (IS_ERR(p)) return p; |
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p[length - 1] = '\0'; return p; } EXPORT_SYMBOL(strndup_user); |
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|
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/** * memdup_user_nul - duplicate memory region from user space and NUL-terminate * * @src: source address in user space * @len: number of bytes to copy * |
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* Return: an ERR_PTR() on failure. |
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*/ void *memdup_user_nul(const void __user *src, size_t len) { char *p; /* * Always use GFP_KERNEL, since copy_from_user() can sleep and * cause pagefault, which makes it pointless to use GFP_NOFS * or GFP_ATOMIC. */ p = kmalloc_track_caller(len + 1, GFP_KERNEL); if (!p) return ERR_PTR(-ENOMEM); if (copy_from_user(p, src, len)) { kfree(p); return ERR_PTR(-EFAULT); } p[len] = '\0'; return p; } EXPORT_SYMBOL(memdup_user_nul); |
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void __vma_link_list(struct mm_struct *mm, struct vm_area_struct *vma, struct vm_area_struct *prev, struct rb_node *rb_parent) { struct vm_area_struct *next; vma->vm_prev = prev; if (prev) { next = prev->vm_next; prev->vm_next = vma; } else { mm->mmap = vma; if (rb_parent) next = rb_entry(rb_parent, struct vm_area_struct, vm_rb); else next = NULL; } vma->vm_next = next; if (next) next->vm_prev = vma; } |
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/* Check if the vma is being used as a stack by this task */ |
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int vma_is_stack_for_current(struct vm_area_struct *vma) |
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{ |
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struct task_struct * __maybe_unused t = current; |
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return (vma->vm_start <= KSTK_ESP(t) && vma->vm_end >= KSTK_ESP(t)); } |
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#ifndef STACK_RND_MASK #define STACK_RND_MASK (0x7ff >> (PAGE_SHIFT - 12)) /* 8MB of VA */ #endif unsigned long randomize_stack_top(unsigned long stack_top) { unsigned long random_variable = 0; if (current->flags & PF_RANDOMIZE) { random_variable = get_random_long(); random_variable &= STACK_RND_MASK; random_variable <<= PAGE_SHIFT; } #ifdef CONFIG_STACK_GROWSUP return PAGE_ALIGN(stack_top) + random_variable; #else return PAGE_ALIGN(stack_top) - random_variable; #endif } |
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#ifdef CONFIG_ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT |
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unsigned long arch_randomize_brk(struct mm_struct *mm) { /* Is the current task 32bit ? */ if (!IS_ENABLED(CONFIG_64BIT) || is_compat_task()) return randomize_page(mm->brk, SZ_32M); return randomize_page(mm->brk, SZ_1G); } |
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unsigned long arch_mmap_rnd(void) { unsigned long rnd; #ifdef CONFIG_HAVE_ARCH_MMAP_RND_COMPAT_BITS if (is_compat_task()) rnd = get_random_long() & ((1UL << mmap_rnd_compat_bits) - 1); else #endif /* CONFIG_HAVE_ARCH_MMAP_RND_COMPAT_BITS */ rnd = get_random_long() & ((1UL << mmap_rnd_bits) - 1); return rnd << PAGE_SHIFT; } |
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static int mmap_is_legacy(struct rlimit *rlim_stack) { if (current->personality & ADDR_COMPAT_LAYOUT) return 1; if (rlim_stack->rlim_cur == RLIM_INFINITY) return 1; return sysctl_legacy_va_layout; } /* * Leave enough space between the mmap area and the stack to honour ulimit in * the face of randomisation. */ #define MIN_GAP (SZ_128M) #define MAX_GAP (STACK_TOP / 6 * 5) static unsigned long mmap_base(unsigned long rnd, struct rlimit *rlim_stack) { unsigned long gap = rlim_stack->rlim_cur; unsigned long pad = stack_guard_gap; /* Account for stack randomization if necessary */ if (current->flags & PF_RANDOMIZE) pad += (STACK_RND_MASK << PAGE_SHIFT); /* Values close to RLIM_INFINITY can overflow. */ if (gap + pad > gap) gap += pad; if (gap < MIN_GAP) gap = MIN_GAP; else if (gap > MAX_GAP) gap = MAX_GAP; return PAGE_ALIGN(STACK_TOP - gap - rnd); } void arch_pick_mmap_layout(struct mm_struct *mm, struct rlimit *rlim_stack) { unsigned long random_factor = 0UL; if (current->flags & PF_RANDOMIZE) random_factor = arch_mmap_rnd(); if (mmap_is_legacy(rlim_stack)) { mm->mmap_base = TASK_UNMAPPED_BASE + random_factor; mm->get_unmapped_area = arch_get_unmapped_area; } else { mm->mmap_base = mmap_base(random_factor, rlim_stack); mm->get_unmapped_area = arch_get_unmapped_area_topdown; } } #elif defined(CONFIG_MMU) && !defined(HAVE_ARCH_PICK_MMAP_LAYOUT) |
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void arch_pick_mmap_layout(struct mm_struct *mm, struct rlimit *rlim_stack) |
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{ mm->mmap_base = TASK_UNMAPPED_BASE; mm->get_unmapped_area = arch_get_unmapped_area; |
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} #endif |
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/** * __account_locked_vm - account locked pages to an mm's locked_vm * @mm: mm to account against * @pages: number of pages to account * @inc: %true if @pages should be considered positive, %false if not * @task: task used to check RLIMIT_MEMLOCK * @bypass_rlim: %true if checking RLIMIT_MEMLOCK should be skipped * * Assumes @task and @mm are valid (i.e. at least one reference on each), and * that mmap_sem is held as writer. * * Return: * * 0 on success * * -ENOMEM if RLIMIT_MEMLOCK would be exceeded. */ int __account_locked_vm(struct mm_struct *mm, unsigned long pages, bool inc, struct task_struct *task, bool bypass_rlim) { unsigned long locked_vm, limit; int ret = 0; lockdep_assert_held_write(&mm->mmap_sem); locked_vm = mm->locked_vm; if (inc) { if (!bypass_rlim) { limit = task_rlimit(task, RLIMIT_MEMLOCK) >> PAGE_SHIFT; if (locked_vm + pages > limit) ret = -ENOMEM; } if (!ret) mm->locked_vm = locked_vm + pages; } else { WARN_ON_ONCE(pages > locked_vm); mm->locked_vm = locked_vm - pages; } pr_debug("%s: [%d] caller %ps %c%lu %lu/%lu%s ", __func__, task->pid, (void *)_RET_IP_, (inc) ? '+' : '-', pages << PAGE_SHIFT, locked_vm << PAGE_SHIFT, task_rlimit(task, RLIMIT_MEMLOCK), ret ? " - exceeded" : ""); return ret; } EXPORT_SYMBOL_GPL(__account_locked_vm); /** * account_locked_vm - account locked pages to an mm's locked_vm * @mm: mm to account against, may be NULL * @pages: number of pages to account * @inc: %true if @pages should be considered positive, %false if not * * Assumes a non-NULL @mm is valid (i.e. at least one reference on it). * * Return: * * 0 on success, or if mm is NULL * * -ENOMEM if RLIMIT_MEMLOCK would be exceeded. */ int account_locked_vm(struct mm_struct *mm, unsigned long pages, bool inc) { int ret; if (pages == 0 || !mm) return 0; down_write(&mm->mmap_sem); ret = __account_locked_vm(mm, pages, inc, current, capable(CAP_IPC_LOCK)); up_write(&mm->mmap_sem); return ret; } EXPORT_SYMBOL_GPL(account_locked_vm); |
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unsigned long vm_mmap_pgoff(struct file *file, unsigned long addr, unsigned long len, unsigned long prot, |
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unsigned long flag, unsigned long pgoff) |
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{ unsigned long ret; struct mm_struct *mm = current->mm; |
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unsigned long populate; |
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LIST_HEAD(uf); |
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ret = security_mmap_file(file, prot, flag); if (!ret) { |
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if (down_write_killable(&mm->mmap_sem)) return -EINTR; |
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ret = do_mmap_pgoff(file, addr, len, prot, flag, pgoff, |
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&populate, &uf); |
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up_write(&mm->mmap_sem); |
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userfaultfd_unmap_complete(mm, &uf); |
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if (populate) mm_populate(ret, populate); |
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} return ret; } unsigned long vm_mmap(struct file *file, unsigned long addr, unsigned long len, unsigned long prot, unsigned long flag, unsigned long offset) { if (unlikely(offset + PAGE_ALIGN(len) < offset)) return -EINVAL; |
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if (unlikely(offset_in_page(offset))) |
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return -EINVAL; |
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return vm_mmap_pgoff(file, addr, len, prot, flag, offset >> PAGE_SHIFT); |
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} EXPORT_SYMBOL(vm_mmap); |
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/** * kvmalloc_node - attempt to allocate physically contiguous memory, but upon * failure, fall back to non-contiguous (vmalloc) allocation. * @size: size of the request. * @flags: gfp mask for the allocation - must be compatible (superset) with GFP_KERNEL. * @node: numa node to allocate from * * Uses kmalloc to get the memory but if the allocation fails then falls back * to the vmalloc allocator. Use kvfree for freeing the memory. * |
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* Reclaim modifiers - __GFP_NORETRY and __GFP_NOFAIL are not supported. * __GFP_RETRY_MAYFAIL is supported, and it should be used only if kmalloc is * preferable to the vmalloc fallback, due to visible performance drawbacks. |
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* |
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* Please note that any use of gfp flags outside of GFP_KERNEL is careful to not * fall back to vmalloc. |
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* * Return: pointer to the allocated memory of %NULL in case of failure |
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*/ void *kvmalloc_node(size_t size, gfp_t flags, int node) { gfp_t kmalloc_flags = flags; void *ret; /* * vmalloc uses GFP_KERNEL for some internal allocations (e.g page tables) * so the given set of flags has to be compatible. */ |
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if ((flags & GFP_KERNEL) != GFP_KERNEL) return kmalloc_node(size, flags, node); |
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/* |
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* We want to attempt a large physically contiguous block first because * it is less likely to fragment multiple larger blocks and therefore * contribute to a long term fragmentation less than vmalloc fallback. * However make sure that larger requests are not too disruptive - no * OOM killer and no allocation failure warnings as we have a fallback. |
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*/ |
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if (size > PAGE_SIZE) { kmalloc_flags |= __GFP_NOWARN; |
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if (!(kmalloc_flags & __GFP_RETRY_MAYFAIL)) |
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kmalloc_flags |= __GFP_NORETRY; } |
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ret = kmalloc_node(size, kmalloc_flags, node); /* * It doesn't really make sense to fallback to vmalloc for sub page * requests */ if (ret || size <= PAGE_SIZE) return ret; |
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return __vmalloc_node_flags_caller(size, node, flags, __builtin_return_address(0)); |
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} EXPORT_SYMBOL(kvmalloc_node); |
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/** |
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* kvfree() - Free memory. * @addr: Pointer to allocated memory. |
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* |
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* kvfree frees memory allocated by any of vmalloc(), kmalloc() or kvmalloc(). * It is slightly more efficient to use kfree() or vfree() if you are certain * that you know which one to use. * |
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* Context: Either preemptible task context or not-NMI interrupt. |
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*/ |
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void kvfree(const void *addr) { if (is_vmalloc_addr(addr)) vfree(addr); else kfree(addr); } EXPORT_SYMBOL(kvfree); |
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/** * kvfree_sensitive - Free a data object containing sensitive information. * @addr: address of the data object to be freed. * @len: length of the data object. * * Use the special memzero_explicit() function to clear the content of a * kvmalloc'ed object containing sensitive data to make sure that the * compiler won't optimize out the data clearing. */ void kvfree_sensitive(const void *addr, size_t len) { if (likely(!ZERO_OR_NULL_PTR(addr))) { memzero_explicit((void *)addr, len); kvfree(addr); } } EXPORT_SYMBOL(kvfree_sensitive); |
e39155ea1 mm: uninline and ... |
594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 |
static inline void *__page_rmapping(struct page *page) { unsigned long mapping; mapping = (unsigned long)page->mapping; mapping &= ~PAGE_MAPPING_FLAGS; return (void *)mapping; } /* Neutral page->mapping pointer to address_space or anon_vma or other */ void *page_rmapping(struct page *page) { page = compound_head(page); return __page_rmapping(page); } |
1aa8aea53 mm: uninline page... |
610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 |
/* * Return true if this page is mapped into pagetables. * For compound page it returns true if any subpage of compound page is mapped. */ bool page_mapped(struct page *page) { int i; if (likely(!PageCompound(page))) return atomic_read(&page->_mapcount) >= 0; page = compound_head(page); if (atomic_read(compound_mapcount_ptr(page)) >= 0) return true; if (PageHuge(page)) return false; |
d8c6546b1 mm: introduce com... |
625 |
for (i = 0; i < compound_nr(page); i++) { |
1aa8aea53 mm: uninline page... |
626 627 628 629 630 631 |
if (atomic_read(&page[i]._mapcount) >= 0) return true; } return false; } EXPORT_SYMBOL(page_mapped); |
e39155ea1 mm: uninline and ... |
632 633 634 635 636 637 638 639 640 641 |
struct anon_vma *page_anon_vma(struct page *page) { unsigned long mapping; page = compound_head(page); mapping = (unsigned long)page->mapping; if ((mapping & PAGE_MAPPING_FLAGS) != PAGE_MAPPING_ANON) return NULL; return __page_rmapping(page); } |
9800339b5 mm: don't inline ... |
642 643 |
struct address_space *page_mapping(struct page *page) { |
1c290f642 mm: sanitize page... |
644 645 646 |
struct address_space *mapping; page = compound_head(page); |
9800339b5 mm: don't inline ... |
647 |
|
03e5ac2fc mm: fix crash whe... |
648 649 650 |
/* This happens if someone calls flush_dcache_page on slab page */ if (unlikely(PageSlab(page))) return NULL; |
33806f06d swap: make each s... |
651 652 653 654 |
if (unlikely(PageSwapCache(page))) { swp_entry_t entry; entry.val = page_private(page); |
e39155ea1 mm: uninline and ... |
655 656 |
return swap_address_space(entry); } |
1c290f642 mm: sanitize page... |
657 |
mapping = page->mapping; |
bda807d44 mm: migrate: supp... |
658 |
if ((unsigned long)mapping & PAGE_MAPPING_ANON) |
e39155ea1 mm: uninline and ... |
659 |
return NULL; |
bda807d44 mm: migrate: supp... |
660 661 |
return (void *)((unsigned long)mapping & ~PAGE_MAPPING_FLAGS); |
9800339b5 mm: don't inline ... |
662 |
} |
bda807d44 mm: migrate: supp... |
663 |
EXPORT_SYMBOL(page_mapping); |
9800339b5 mm: don't inline ... |
664 |
|
cb9f753a3 mm: fix races bet... |
665 666 667 668 669 670 671 672 673 |
/* * For file cache pages, return the address_space, otherwise return NULL */ struct address_space *page_mapping_file(struct page *page) { if (unlikely(PageSwapCache(page))) return NULL; return page_mapping(page); } |
b20ce5e03 mm: prepare page_... |
674 675 676 677 678 679 |
/* Slow path of page_mapcount() for compound pages */ int __page_mapcount(struct page *page) { int ret; ret = atomic_read(&page->_mapcount) + 1; |
dd78fedde rmap: support fil... |
680 681 682 683 684 685 |
/* * For file THP page->_mapcount contains total number of mapping * of the page: no need to look into compound_mapcount. */ if (!PageAnon(page) && !PageHuge(page)) return ret; |
b20ce5e03 mm: prepare page_... |
686 687 688 689 690 691 692 |
page = compound_head(page); ret += atomic_read(compound_mapcount_ptr(page)) + 1; if (PageDoubleMap(page)) ret--; return ret; } EXPORT_SYMBOL_GPL(__page_mapcount); |
39a1aa8e1 mm: deduplicate m... |
693 694 695 696 697 698 |
int sysctl_overcommit_memory __read_mostly = OVERCOMMIT_GUESS; int sysctl_overcommit_ratio __read_mostly = 50; unsigned long sysctl_overcommit_kbytes __read_mostly; int sysctl_max_map_count __read_mostly = DEFAULT_MAX_MAP_COUNT; unsigned long sysctl_user_reserve_kbytes __read_mostly = 1UL << 17; /* 128MB */ unsigned long sysctl_admin_reserve_kbytes __read_mostly = 1UL << 13; /* 8MB */ |
49f0ce5f9 mm: add overcommi... |
699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 |
int overcommit_ratio_handler(struct ctl_table *table, int write, void __user *buffer, size_t *lenp, loff_t *ppos) { int ret; ret = proc_dointvec(table, write, buffer, lenp, ppos); if (ret == 0 && write) sysctl_overcommit_kbytes = 0; return ret; } int overcommit_kbytes_handler(struct ctl_table *table, int write, void __user *buffer, size_t *lenp, loff_t *ppos) { int ret; ret = proc_doulongvec_minmax(table, write, buffer, lenp, ppos); if (ret == 0 && write) sysctl_overcommit_ratio = 0; return ret; } |
00619bcc4 mm: factor commit... |
722 723 724 725 726 |
/* * Committed memory limit enforced when OVERCOMMIT_NEVER policy is used */ unsigned long vm_commit_limit(void) { |
49f0ce5f9 mm: add overcommi... |
727 728 729 730 731 |
unsigned long allowed; if (sysctl_overcommit_kbytes) allowed = sysctl_overcommit_kbytes >> (PAGE_SHIFT - 10); else |
ca79b0c21 mm: convert total... |
732 |
allowed = ((totalram_pages() - hugetlb_total_pages()) |
49f0ce5f9 mm: add overcommi... |
733 734 735 736 |
* sysctl_overcommit_ratio / 100); allowed += total_swap_pages; return allowed; |
00619bcc4 mm: factor commit... |
737 |
} |
39a1aa8e1 mm: deduplicate m... |
738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 |
/* * Make sure vm_committed_as in one cacheline and not cacheline shared with * other variables. It can be updated by several CPUs frequently. */ struct percpu_counter vm_committed_as ____cacheline_aligned_in_smp; /* * The global memory commitment made in the system can be a metric * that can be used to drive ballooning decisions when Linux is hosted * as a guest. On Hyper-V, the host implements a policy engine for dynamically * balancing memory across competing virtual machines that are hosted. * Several metrics drive this policy engine including the guest reported * memory commitment. */ unsigned long vm_memory_committed(void) { return percpu_counter_read_positive(&vm_committed_as); } EXPORT_SYMBOL_GPL(vm_memory_committed); /* * Check that a process has enough memory to allocate a new virtual * mapping. 0 means there is enough memory for the allocation to * succeed and -ENOMEM implies there is not. * * We currently support three overcommit policies, which are set via the |
ad56b738c docs/vm: rename d... |
764 |
* vm.overcommit_memory sysctl. See Documentation/vm/overcommit-accounting.rst |
39a1aa8e1 mm: deduplicate m... |
765 766 767 768 769 770 771 772 773 774 775 |
* * Strict overcommit modes added 2002 Feb 26 by Alan Cox. * Additional code 2002 Jul 20 by Robert Love. * * cap_sys_admin is 1 if the process has admin privileges, 0 otherwise. * * Note this is a helper function intended to be used by LSMs which * wish to use this logic. */ int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin) { |
8c7829b04 mm: fix false-pos... |
776 |
long allowed; |
39a1aa8e1 mm: deduplicate m... |
777 778 779 780 781 782 783 784 785 786 787 788 789 790 |
VM_WARN_ONCE(percpu_counter_read(&vm_committed_as) < -(s64)vm_committed_as_batch * num_online_cpus(), "memory commitment underflow"); vm_acct_memory(pages); /* * Sometimes we want to use more memory than we have */ if (sysctl_overcommit_memory == OVERCOMMIT_ALWAYS) return 0; if (sysctl_overcommit_memory == OVERCOMMIT_GUESS) { |
8c7829b04 mm: fix false-pos... |
791 |
if (pages > totalram_pages() + total_swap_pages) |
39a1aa8e1 mm: deduplicate m... |
792 |
goto error; |
8c7829b04 mm: fix false-pos... |
793 |
return 0; |
39a1aa8e1 mm: deduplicate m... |
794 795 796 797 798 799 800 801 802 803 804 805 806 |
} allowed = vm_commit_limit(); /* * Reserve some for root */ if (!cap_sys_admin) allowed -= sysctl_admin_reserve_kbytes >> (PAGE_SHIFT - 10); /* * Don't let a single process grow so big a user can't recover */ if (mm) { |
8c7829b04 mm: fix false-pos... |
807 |
long reserve = sysctl_user_reserve_kbytes >> (PAGE_SHIFT - 10); |
39a1aa8e1 mm: deduplicate m... |
808 809 810 811 812 813 814 815 816 817 |
allowed -= min_t(long, mm->total_vm / 32, reserve); } if (percpu_counter_read_positive(&vm_committed_as) < allowed) return 0; error: vm_unacct_memory(pages); return -ENOMEM; } |
a90902531 mm: Create utilit... |
818 819 820 821 822 823 |
/** * get_cmdline() - copy the cmdline value to a buffer. * @task: the task whose cmdline value to copy. * @buffer: the buffer to copy to. * @buflen: the length of the buffer. Larger cmdline values are truncated * to this length. |
a862f68a8 docs/core-api/mm:... |
824 825 |
* * Return: the size of the cmdline field copied. Note that the copy does |
a90902531 mm: Create utilit... |
826 827 828 829 830 831 832 |
* not guarantee an ending NULL byte. */ int get_cmdline(struct task_struct *task, char *buffer, int buflen) { int res = 0; unsigned int len; struct mm_struct *mm = get_task_mm(task); |
a3b609ef9 proc read mm's {a... |
833 |
unsigned long arg_start, arg_end, env_start, env_end; |
a90902531 mm: Create utilit... |
834 835 836 837 |
if (!mm) goto out; if (!mm->arg_end) goto out_mm; /* Shh! No looking before we're done */ |
bc81426f5 prctl_set_mm: dow... |
838 |
spin_lock(&mm->arg_lock); |
a3b609ef9 proc read mm's {a... |
839 840 841 842 |
arg_start = mm->arg_start; arg_end = mm->arg_end; env_start = mm->env_start; env_end = mm->env_end; |
bc81426f5 prctl_set_mm: dow... |
843 |
spin_unlock(&mm->arg_lock); |
a3b609ef9 proc read mm's {a... |
844 845 |
len = arg_end - arg_start; |
a90902531 mm: Create utilit... |
846 847 848 |
if (len > buflen) len = buflen; |
f307ab6dc mm: replace acces... |
849 |
res = access_process_vm(task, arg_start, buffer, len, FOLL_FORCE); |
a90902531 mm: Create utilit... |
850 851 852 853 854 855 856 857 858 859 |
/* * If the nul at the end of args has been overwritten, then * assume application is using setproctitle(3). */ if (res > 0 && buffer[res-1] != '\0' && len < buflen) { len = strnlen(buffer, res); if (len < res) { res = len; } else { |
a3b609ef9 proc read mm's {a... |
860 |
len = env_end - env_start; |
a90902531 mm: Create utilit... |
861 862 |
if (len > buflen - res) len = buflen - res; |
a3b609ef9 proc read mm's {a... |
863 |
res += access_process_vm(task, env_start, |
f307ab6dc mm: replace acces... |
864 865 |
buffer+res, len, FOLL_FORCE); |
a90902531 mm: Create utilit... |
866 867 868 869 870 871 872 873 |
res = strnlen(buffer, res); } } out_mm: mmput(mm); out: return res; } |
010c164a5 mm: move memcmp_p... |
874 875 876 877 878 879 880 881 882 883 884 885 886 |
int memcmp_pages(struct page *page1, struct page *page2) { char *addr1, *addr2; int ret; addr1 = kmap_atomic(page1); addr2 = kmap_atomic(page2); ret = memcmp(addr1, addr2, PAGE_SIZE); kunmap_atomic(addr2); kunmap_atomic(addr1); return ret; } |