#include <linux/mm.h> #include <linux/slab.h> #include <linux/string.h> #include <linux/export.h> #include <linux/err.h> #include <linux/sched.h> #include <linux/security.h> #include <linux/swap.h> #include <linux/swapops.h> #include <linux/mman.h> #include <linux/hugetlb.h> #include <asm/uaccess.h> #include "internal.h" #define CREATE_TRACE_POINTS #include <trace/events/kmem.h> /** * kstrdup - allocate space for and copy an existing string * @s: the string to duplicate * @gfp: the GFP mask used in the kmalloc() call when allocating memory */ char *kstrdup(const char *s, gfp_t gfp) { size_t len; char *buf; if (!s) return NULL; len = strlen(s) + 1; buf = kmalloc_track_caller(len, gfp); if (buf) memcpy(buf, s, len); return buf; } EXPORT_SYMBOL(kstrdup); /** * 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 */ 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); /** * kmemdup - duplicate region of memory * * @src: memory region to duplicate * @len: memory region length * @gfp: GFP mask to use */ void *kmemdup(const void *src, size_t len, gfp_t gfp) { void *p; p = kmalloc_track_caller(len, gfp); if (p) memcpy(p, src, len); return p; } EXPORT_SYMBOL(kmemdup); /** * memdup_user - duplicate memory region from user space * * @src: source address in user space * @len: number of bytes to copy * * Returns an ERR_PTR() on failure. */ void *memdup_user(const void __user *src, size_t len) { void *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, GFP_KERNEL); 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); static __always_inline void *__do_krealloc(const void *p, size_t new_size, gfp_t flags) { void *ret; size_t ks = 0; if (p) ks = ksize(p); if (ks >= new_size) return (void *)p; ret = kmalloc_track_caller(new_size, flags); if (ret && p) memcpy(ret, p, ks); return ret; } /** * __krealloc - like krealloc() but don't free @p. * @p: object to reallocate memory for. * @new_size: how many bytes of memory are required. * @flags: the type of memory to allocate. * * This function is like krealloc() except it never frees the originally * allocated buffer. Use this if you don't want to free the buffer immediately * like, for example, with RCU. */ void *__krealloc(const void *p, size_t new_size, gfp_t flags) { if (unlikely(!new_size)) return ZERO_SIZE_PTR; return __do_krealloc(p, new_size, flags); } EXPORT_SYMBOL(__krealloc); /** * krealloc - reallocate memory. The contents will remain unchanged. * @p: object to reallocate memory for. * @new_size: how many bytes of memory are required. * @flags: the type of memory to allocate. * * The contents of the object pointed to are preserved up to the * lesser of the new and old sizes. If @p is %NULL, krealloc() * behaves exactly like kmalloc(). If @new_size is 0 and @p is not a * %NULL pointer, the object pointed to is freed. */ void *krealloc(const void *p, size_t new_size, gfp_t flags) { void *ret; if (unlikely(!new_size)) { kfree(p); return ZERO_SIZE_PTR; } ret = __do_krealloc(p, new_size, flags); if (ret && p != ret) kfree(p); return ret; } EXPORT_SYMBOL(krealloc); /** * kzfree - like kfree but zero memory * @p: object to free memory of * * The memory of the object @p points to is zeroed before freed. * If @p is %NULL, kzfree() does nothing. * * Note: this function zeroes the whole allocated buffer which can be a good * deal bigger than the requested buffer size passed to kmalloc(). So be * careful when using this function in performance sensitive code. */ void kzfree(const void *p) { size_t ks; void *mem = (void *)p; if (unlikely(ZERO_OR_NULL_PTR(mem))) return; ks = ksize(mem); memset(mem, 0, ks); kfree(mem); } EXPORT_SYMBOL(kzfree); /* * strndup_user - duplicate an existing string from user space * @s: The string to duplicate * @n: Maximum number of bytes to copy, including the trailing NUL. */ 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); p = memdup_user(s, length); if (IS_ERR(p)) return p; p[length - 1] = '\0'; return p; } EXPORT_SYMBOL(strndup_user); 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; } /* Check if the vma is being used as a stack by this task */ static int vm_is_stack_for_task(struct task_struct *t, struct vm_area_struct *vma) { return (vma->vm_start <= KSTK_ESP(t) && vma->vm_end >= KSTK_ESP(t)); } /* * Check if the vma is being used as a stack. * If is_group is non-zero, check in the entire thread group or else * just check in the current task. Returns the pid of the task that * the vma is stack for. */ pid_t vm_is_stack(struct task_struct *task, struct vm_area_struct *vma, int in_group) { pid_t ret = 0; if (vm_is_stack_for_task(task, vma)) return task->pid; if (in_group) { struct task_struct *t; rcu_read_lock(); if (!pid_alive(task)) goto done; t = task; do { if (vm_is_stack_for_task(t, vma)) { ret = t->pid; goto done; } } while_each_thread(task, t); done: rcu_read_unlock(); } return ret; } #if defined(CONFIG_MMU) && !defined(HAVE_ARCH_PICK_MMAP_LAYOUT) void arch_pick_mmap_layout(struct mm_struct *mm) { mm->mmap_base = TASK_UNMAPPED_BASE; mm->get_unmapped_area = arch_get_unmapped_area; } #endif /* * Like get_user_pages_fast() except its IRQ-safe in that it won't fall * back to the regular GUP. * If the architecture not support this function, simply return with no * page pinned */ int __attribute__((weak)) __get_user_pages_fast(unsigned long start, int nr_pages, int write, struct page **pages) { return 0; } EXPORT_SYMBOL_GPL(__get_user_pages_fast); /** * get_user_pages_fast() - pin user pages in memory * @start: starting user address * @nr_pages: number of pages from start to pin * @write: whether pages will be written to * @pages: array that receives pointers to the pages pinned. * Should be at least nr_pages long. * * Returns number of pages pinned. This may be fewer than the number * requested. If nr_pages is 0 or negative, returns 0. If no pages * were pinned, returns -errno. * * get_user_pages_fast provides equivalent functionality to get_user_pages, * operating on current and current->mm, with force=0 and vma=NULL. However * unlike get_user_pages, it must be called without mmap_sem held. * * get_user_pages_fast may take mmap_sem and page table locks, so no * assumptions can be made about lack of locking. get_user_pages_fast is to be * implemented in a way that is advantageous (vs get_user_pages()) when the * user memory area is already faulted in and present in ptes. However if the * pages have to be faulted in, it may turn out to be slightly slower so * callers need to carefully consider what to use. On many architectures, * get_user_pages_fast simply falls back to get_user_pages. */ int __attribute__((weak)) get_user_pages_fast(unsigned long start, int nr_pages, int write, struct page **pages) { struct mm_struct *mm = current->mm; int ret; down_read(&mm->mmap_sem); ret = get_user_pages(current, mm, start, nr_pages, write, 0, pages, NULL); up_read(&mm->mmap_sem); return ret; } EXPORT_SYMBOL_GPL(get_user_pages_fast); unsigned long vm_mmap_pgoff(struct file *file, unsigned long addr, unsigned long len, unsigned long prot, unsigned long flag, unsigned long pgoff) { unsigned long ret; struct mm_struct *mm = current->mm; unsigned long populate; ret = security_mmap_file(file, prot, flag); if (!ret) { down_write(&mm->mmap_sem); ret = do_mmap_pgoff(file, addr, len, prot, flag, pgoff, &populate); up_write(&mm->mmap_sem); if (populate) mm_populate(ret, populate); } 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; if (unlikely(offset & ~PAGE_MASK)) return -EINVAL; return vm_mmap_pgoff(file, addr, len, prot, flag, offset >> PAGE_SHIFT); } EXPORT_SYMBOL(vm_mmap); struct address_space *page_mapping(struct page *page) { struct address_space *mapping = page->mapping; /* This happens if someone calls flush_dcache_page on slab page */ if (unlikely(PageSlab(page))) return NULL; if (unlikely(PageSwapCache(page))) { swp_entry_t entry; entry.val = page_private(page); mapping = swap_address_space(entry); } else if ((unsigned long)mapping & PAGE_MAPPING_ANON) mapping = NULL; return mapping; } 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; } /* * Committed memory limit enforced when OVERCOMMIT_NEVER policy is used */ unsigned long vm_commit_limit(void) { unsigned long allowed; if (sysctl_overcommit_kbytes) allowed = sysctl_overcommit_kbytes >> (PAGE_SHIFT - 10); else allowed = ((totalram_pages - hugetlb_total_pages()) * sysctl_overcommit_ratio / 100); allowed += total_swap_pages; return allowed; } /* Tracepoints definitions. */ EXPORT_TRACEPOINT_SYMBOL(kmalloc); EXPORT_TRACEPOINT_SYMBOL(kmem_cache_alloc); EXPORT_TRACEPOINT_SYMBOL(kmalloc_node); EXPORT_TRACEPOINT_SYMBOL(kmem_cache_alloc_node); EXPORT_TRACEPOINT_SYMBOL(kfree); EXPORT_TRACEPOINT_SYMBOL(kmem_cache_free);