| 1 | #include <linux/mm.h> |
| 2 | #include <linux/slab.h> |
| 3 | #include <linux/string.h> |
| 4 | #include <linux/module.h> |
| 5 | #include <linux/err.h> |
| 6 | #include <linux/sched.h> |
| 7 | #include <asm/uaccess.h> |
| 8 | |
| 9 | #include "internal.h" |
| 10 | |
| 11 | #define CREATE_TRACE_POINTS |
| 12 | #include <trace/events/kmem.h> |
| 13 | |
| 14 | /** |
| 15 | * kstrdup - allocate space for and copy an existing string |
| 16 | * @s: the string to duplicate |
| 17 | * @gfp: the GFP mask used in the kmalloc() call when allocating memory |
| 18 | */ |
| 19 | char *kstrdup(const char *s, gfp_t gfp) |
| 20 | { |
| 21 | size_t len; |
| 22 | char *buf; |
| 23 | |
| 24 | if (!s) |
| 25 | return NULL; |
| 26 | |
| 27 | len = strlen(s) + 1; |
| 28 | buf = kmalloc_track_caller(len, gfp); |
| 29 | if (buf) |
| 30 | memcpy(buf, s, len); |
| 31 | return buf; |
| 32 | } |
| 33 | EXPORT_SYMBOL(kstrdup); |
| 34 | |
| 35 | /** |
| 36 | * kstrndup - allocate space for and copy an existing string |
| 37 | * @s: the string to duplicate |
| 38 | * @max: read at most @max chars from @s |
| 39 | * @gfp: the GFP mask used in the kmalloc() call when allocating memory |
| 40 | */ |
| 41 | char *kstrndup(const char *s, size_t max, gfp_t gfp) |
| 42 | { |
| 43 | size_t len; |
| 44 | char *buf; |
| 45 | |
| 46 | if (!s) |
| 47 | return NULL; |
| 48 | |
| 49 | len = strnlen(s, max); |
| 50 | buf = kmalloc_track_caller(len+1, gfp); |
| 51 | if (buf) { |
| 52 | memcpy(buf, s, len); |
| 53 | buf[len] = '\0'; |
| 54 | } |
| 55 | return buf; |
| 56 | } |
| 57 | EXPORT_SYMBOL(kstrndup); |
| 58 | |
| 59 | /** |
| 60 | * kmemdup - duplicate region of memory |
| 61 | * |
| 62 | * @src: memory region to duplicate |
| 63 | * @len: memory region length |
| 64 | * @gfp: GFP mask to use |
| 65 | */ |
| 66 | void *kmemdup(const void *src, size_t len, gfp_t gfp) |
| 67 | { |
| 68 | void *p; |
| 69 | |
| 70 | p = kmalloc_track_caller(len, gfp); |
| 71 | if (p) |
| 72 | memcpy(p, src, len); |
| 73 | return p; |
| 74 | } |
| 75 | EXPORT_SYMBOL(kmemdup); |
| 76 | |
| 77 | /** |
| 78 | * memdup_user - duplicate memory region from user space |
| 79 | * |
| 80 | * @src: source address in user space |
| 81 | * @len: number of bytes to copy |
| 82 | * |
| 83 | * Returns an ERR_PTR() on failure. |
| 84 | */ |
| 85 | void *memdup_user(const void __user *src, size_t len) |
| 86 | { |
| 87 | void *p; |
| 88 | |
| 89 | /* |
| 90 | * Always use GFP_KERNEL, since copy_from_user() can sleep and |
| 91 | * cause pagefault, which makes it pointless to use GFP_NOFS |
| 92 | * or GFP_ATOMIC. |
| 93 | */ |
| 94 | p = kmalloc_track_caller(len, GFP_KERNEL); |
| 95 | if (!p) |
| 96 | return ERR_PTR(-ENOMEM); |
| 97 | |
| 98 | if (copy_from_user(p, src, len)) { |
| 99 | kfree(p); |
| 100 | return ERR_PTR(-EFAULT); |
| 101 | } |
| 102 | |
| 103 | return p; |
| 104 | } |
| 105 | EXPORT_SYMBOL(memdup_user); |
| 106 | |
| 107 | /** |
| 108 | * __krealloc - like krealloc() but don't free @p. |
| 109 | * @p: object to reallocate memory for. |
| 110 | * @new_size: how many bytes of memory are required. |
| 111 | * @flags: the type of memory to allocate. |
| 112 | * |
| 113 | * This function is like krealloc() except it never frees the originally |
| 114 | * allocated buffer. Use this if you don't want to free the buffer immediately |
| 115 | * like, for example, with RCU. |
| 116 | */ |
| 117 | void *__krealloc(const void *p, size_t new_size, gfp_t flags) |
| 118 | { |
| 119 | void *ret; |
| 120 | size_t ks = 0; |
| 121 | |
| 122 | if (unlikely(!new_size)) |
| 123 | return ZERO_SIZE_PTR; |
| 124 | |
| 125 | if (p) |
| 126 | ks = ksize(p); |
| 127 | |
| 128 | if (ks >= new_size) |
| 129 | return (void *)p; |
| 130 | |
| 131 | ret = kmalloc_track_caller(new_size, flags); |
| 132 | if (ret && p) |
| 133 | memcpy(ret, p, ks); |
| 134 | |
| 135 | return ret; |
| 136 | } |
| 137 | EXPORT_SYMBOL(__krealloc); |
| 138 | |
| 139 | /** |
| 140 | * krealloc - reallocate memory. The contents will remain unchanged. |
| 141 | * @p: object to reallocate memory for. |
| 142 | * @new_size: how many bytes of memory are required. |
| 143 | * @flags: the type of memory to allocate. |
| 144 | * |
| 145 | * The contents of the object pointed to are preserved up to the |
| 146 | * lesser of the new and old sizes. If @p is %NULL, krealloc() |
| 147 | * behaves exactly like kmalloc(). If @size is 0 and @p is not a |
| 148 | * %NULL pointer, the object pointed to is freed. |
| 149 | */ |
| 150 | void *krealloc(const void *p, size_t new_size, gfp_t flags) |
| 151 | { |
| 152 | void *ret; |
| 153 | |
| 154 | if (unlikely(!new_size)) { |
| 155 | kfree(p); |
| 156 | return ZERO_SIZE_PTR; |
| 157 | } |
| 158 | |
| 159 | ret = __krealloc(p, new_size, flags); |
| 160 | if (ret && p != ret) |
| 161 | kfree(p); |
| 162 | |
| 163 | return ret; |
| 164 | } |
| 165 | EXPORT_SYMBOL(krealloc); |
| 166 | |
| 167 | /** |
| 168 | * kzfree - like kfree but zero memory |
| 169 | * @p: object to free memory of |
| 170 | * |
| 171 | * The memory of the object @p points to is zeroed before freed. |
| 172 | * If @p is %NULL, kzfree() does nothing. |
| 173 | * |
| 174 | * Note: this function zeroes the whole allocated buffer which can be a good |
| 175 | * deal bigger than the requested buffer size passed to kmalloc(). So be |
| 176 | * careful when using this function in performance sensitive code. |
| 177 | */ |
| 178 | void kzfree(const void *p) |
| 179 | { |
| 180 | size_t ks; |
| 181 | void *mem = (void *)p; |
| 182 | |
| 183 | if (unlikely(ZERO_OR_NULL_PTR(mem))) |
| 184 | return; |
| 185 | ks = ksize(mem); |
| 186 | memset(mem, 0, ks); |
| 187 | kfree(mem); |
| 188 | } |
| 189 | EXPORT_SYMBOL(kzfree); |
| 190 | |
| 191 | /* |
| 192 | * strndup_user - duplicate an existing string from user space |
| 193 | * @s: The string to duplicate |
| 194 | * @n: Maximum number of bytes to copy, including the trailing NUL. |
| 195 | */ |
| 196 | char *strndup_user(const char __user *s, long n) |
| 197 | { |
| 198 | char *p; |
| 199 | long length; |
| 200 | |
| 201 | length = strnlen_user(s, n); |
| 202 | |
| 203 | if (!length) |
| 204 | return ERR_PTR(-EFAULT); |
| 205 | |
| 206 | if (length > n) |
| 207 | return ERR_PTR(-EINVAL); |
| 208 | |
| 209 | p = memdup_user(s, length); |
| 210 | |
| 211 | if (IS_ERR(p)) |
| 212 | return p; |
| 213 | |
| 214 | p[length - 1] = '\0'; |
| 215 | |
| 216 | return p; |
| 217 | } |
| 218 | EXPORT_SYMBOL(strndup_user); |
| 219 | |
| 220 | void __vma_link_list(struct mm_struct *mm, struct vm_area_struct *vma, |
| 221 | struct vm_area_struct *prev, struct rb_node *rb_parent) |
| 222 | { |
| 223 | struct vm_area_struct *next; |
| 224 | |
| 225 | vma->vm_prev = prev; |
| 226 | if (prev) { |
| 227 | next = prev->vm_next; |
| 228 | prev->vm_next = vma; |
| 229 | } else { |
| 230 | mm->mmap = vma; |
| 231 | if (rb_parent) |
| 232 | next = rb_entry(rb_parent, |
| 233 | struct vm_area_struct, vm_rb); |
| 234 | else |
| 235 | next = NULL; |
| 236 | } |
| 237 | vma->vm_next = next; |
| 238 | if (next) |
| 239 | next->vm_prev = vma; |
| 240 | } |
| 241 | |
| 242 | #if defined(CONFIG_MMU) && !defined(HAVE_ARCH_PICK_MMAP_LAYOUT) |
| 243 | void arch_pick_mmap_layout(struct mm_struct *mm) |
| 244 | { |
| 245 | mm->mmap_base = TASK_UNMAPPED_BASE; |
| 246 | mm->get_unmapped_area = arch_get_unmapped_area; |
| 247 | mm->unmap_area = arch_unmap_area; |
| 248 | } |
| 249 | #endif |
| 250 | |
| 251 | /* |
| 252 | * Like get_user_pages_fast() except its IRQ-safe in that it won't fall |
| 253 | * back to the regular GUP. |
| 254 | * If the architecture not support this function, simply return with no |
| 255 | * page pinned |
| 256 | */ |
| 257 | int __attribute__((weak)) __get_user_pages_fast(unsigned long start, |
| 258 | int nr_pages, int write, struct page **pages) |
| 259 | { |
| 260 | return 0; |
| 261 | } |
| 262 | EXPORT_SYMBOL_GPL(__get_user_pages_fast); |
| 263 | |
| 264 | /** |
| 265 | * get_user_pages_fast() - pin user pages in memory |
| 266 | * @start: starting user address |
| 267 | * @nr_pages: number of pages from start to pin |
| 268 | * @write: whether pages will be written to |
| 269 | * @pages: array that receives pointers to the pages pinned. |
| 270 | * Should be at least nr_pages long. |
| 271 | * |
| 272 | * Returns number of pages pinned. This may be fewer than the number |
| 273 | * requested. If nr_pages is 0 or negative, returns 0. If no pages |
| 274 | * were pinned, returns -errno. |
| 275 | * |
| 276 | * get_user_pages_fast provides equivalent functionality to get_user_pages, |
| 277 | * operating on current and current->mm, with force=0 and vma=NULL. However |
| 278 | * unlike get_user_pages, it must be called without mmap_sem held. |
| 279 | * |
| 280 | * get_user_pages_fast may take mmap_sem and page table locks, so no |
| 281 | * assumptions can be made about lack of locking. get_user_pages_fast is to be |
| 282 | * implemented in a way that is advantageous (vs get_user_pages()) when the |
| 283 | * user memory area is already faulted in and present in ptes. However if the |
| 284 | * pages have to be faulted in, it may turn out to be slightly slower so |
| 285 | * callers need to carefully consider what to use. On many architectures, |
| 286 | * get_user_pages_fast simply falls back to get_user_pages. |
| 287 | */ |
| 288 | int __attribute__((weak)) get_user_pages_fast(unsigned long start, |
| 289 | int nr_pages, int write, struct page **pages) |
| 290 | { |
| 291 | struct mm_struct *mm = current->mm; |
| 292 | int ret; |
| 293 | |
| 294 | down_read(&mm->mmap_sem); |
| 295 | ret = get_user_pages(current, mm, start, nr_pages, |
| 296 | write, 0, pages, NULL); |
| 297 | up_read(&mm->mmap_sem); |
| 298 | |
| 299 | return ret; |
| 300 | } |
| 301 | EXPORT_SYMBOL_GPL(get_user_pages_fast); |
| 302 | |
| 303 | /* Tracepoints definitions. */ |
| 304 | EXPORT_TRACEPOINT_SYMBOL(kmalloc); |
| 305 | EXPORT_TRACEPOINT_SYMBOL(kmem_cache_alloc); |
| 306 | EXPORT_TRACEPOINT_SYMBOL(kmalloc_node); |
| 307 | EXPORT_TRACEPOINT_SYMBOL(kmem_cache_alloc_node); |
| 308 | EXPORT_TRACEPOINT_SYMBOL(kfree); |
| 309 | EXPORT_TRACEPOINT_SYMBOL(kmem_cache_free); |