Glauber Costa | ca23386 | 2008-06-13 14:39:25 -0300 | [diff] [blame] | 1 | #ifndef _ASM_UACCES_H_ |
| 2 | #define _ASM_UACCES_H_ |
| 3 | /* |
| 4 | * User space memory access functions |
| 5 | */ |
| 6 | #include <linux/errno.h> |
| 7 | #include <linux/compiler.h> |
| 8 | #include <linux/thread_info.h> |
| 9 | #include <linux/prefetch.h> |
| 10 | #include <linux/string.h> |
| 11 | #include <asm/asm.h> |
| 12 | #include <asm/page.h> |
| 13 | |
| 14 | #define VERIFY_READ 0 |
| 15 | #define VERIFY_WRITE 1 |
| 16 | |
| 17 | /* |
| 18 | * The fs value determines whether argument validity checking should be |
| 19 | * performed or not. If get_fs() == USER_DS, checking is performed, with |
| 20 | * get_fs() == KERNEL_DS, checking is bypassed. |
| 21 | * |
| 22 | * For historical reasons, these macros are grossly misnamed. |
| 23 | */ |
| 24 | |
| 25 | #define MAKE_MM_SEG(s) ((mm_segment_t) { (s) }) |
| 26 | |
| 27 | #define KERNEL_DS MAKE_MM_SEG(-1UL) |
| 28 | #define USER_DS MAKE_MM_SEG(PAGE_OFFSET) |
| 29 | |
| 30 | #define get_ds() (KERNEL_DS) |
| 31 | #define get_fs() (current_thread_info()->addr_limit) |
| 32 | #define set_fs(x) (current_thread_info()->addr_limit = (x)) |
| 33 | |
| 34 | #define segment_eq(a, b) ((a).seg == (b).seg) |
| 35 | |
Glauber Costa | 002ca16 | 2008-06-25 11:08:51 -0300 | [diff] [blame] | 36 | #define __addr_ok(addr) \ |
| 37 | ((unsigned long __force)(addr) < \ |
| 38 | (current_thread_info()->addr_limit.seg)) |
| 39 | |
Glauber Costa | ca23386 | 2008-06-13 14:39:25 -0300 | [diff] [blame] | 40 | /* |
| 41 | * Test whether a block of memory is a valid user space address. |
| 42 | * Returns 0 if the range is valid, nonzero otherwise. |
| 43 | * |
| 44 | * This is equivalent to the following test: |
| 45 | * (u33)addr + (u33)size >= (u33)current->addr_limit.seg (u65 for x86_64) |
| 46 | * |
| 47 | * This needs 33-bit (65-bit for x86_64) arithmetic. We have a carry... |
| 48 | */ |
| 49 | |
| 50 | #define __range_not_ok(addr, size) \ |
| 51 | ({ \ |
| 52 | unsigned long flag, roksum; \ |
| 53 | __chk_user_ptr(addr); \ |
| 54 | asm("add %3,%1 ; sbb %0,%0 ; cmp %1,%4 ; sbb $0,%0" \ |
| 55 | : "=&r" (flag), "=r" (roksum) \ |
| 56 | : "1" (addr), "g" ((long)(size)), \ |
| 57 | "rm" (current_thread_info()->addr_limit.seg)); \ |
| 58 | flag; \ |
| 59 | }) |
| 60 | |
| 61 | /** |
| 62 | * access_ok: - Checks if a user space pointer is valid |
| 63 | * @type: Type of access: %VERIFY_READ or %VERIFY_WRITE. Note that |
| 64 | * %VERIFY_WRITE is a superset of %VERIFY_READ - if it is safe |
| 65 | * to write to a block, it is always safe to read from it. |
| 66 | * @addr: User space pointer to start of block to check |
| 67 | * @size: Size of block to check |
| 68 | * |
| 69 | * Context: User context only. This function may sleep. |
| 70 | * |
| 71 | * Checks if a pointer to a block of memory in user space is valid. |
| 72 | * |
| 73 | * Returns true (nonzero) if the memory block may be valid, false (zero) |
| 74 | * if it is definitely invalid. |
| 75 | * |
| 76 | * Note that, depending on architecture, this function probably just |
| 77 | * checks that the pointer is in the user space range - after calling |
| 78 | * this function, memory access functions may still return -EFAULT. |
| 79 | */ |
| 80 | #define access_ok(type, addr, size) (likely(__range_not_ok(addr, size) == 0)) |
| 81 | |
| 82 | /* |
| 83 | * The exception table consists of pairs of addresses: the first is the |
| 84 | * address of an instruction that is allowed to fault, and the second is |
| 85 | * the address at which the program should continue. No registers are |
| 86 | * modified, so it is entirely up to the continuation code to figure out |
| 87 | * what to do. |
| 88 | * |
| 89 | * All the routines below use bits of fixup code that are out of line |
| 90 | * with the main instruction path. This means when everything is well, |
| 91 | * we don't even have to jump over them. Further, they do not intrude |
| 92 | * on our cache or tlb entries. |
| 93 | */ |
| 94 | |
| 95 | struct exception_table_entry { |
| 96 | unsigned long insn, fixup; |
| 97 | }; |
| 98 | |
| 99 | extern int fixup_exception(struct pt_regs *regs); |
| 100 | |
| 101 | /* |
| 102 | * These are the main single-value transfer routines. They automatically |
| 103 | * use the right size if we just have the right pointer type. |
| 104 | * |
| 105 | * This gets kind of ugly. We want to return _two_ values in "get_user()" |
| 106 | * and yet we don't want to do any pointers, because that is too much |
| 107 | * of a performance impact. Thus we have a few rather ugly macros here, |
| 108 | * and hide all the ugliness from the user. |
| 109 | * |
| 110 | * The "__xxx" versions of the user access functions are versions that |
| 111 | * do not verify the address space, that must have been done previously |
| 112 | * with a separate "access_ok()" call (this is used when we do multiple |
| 113 | * accesses to the same area of user memory). |
| 114 | */ |
| 115 | |
| 116 | extern int __get_user_1(void); |
| 117 | extern int __get_user_2(void); |
| 118 | extern int __get_user_4(void); |
| 119 | extern int __get_user_8(void); |
| 120 | extern int __get_user_bad(void); |
| 121 | |
| 122 | #define __get_user_x(size, ret, x, ptr) \ |
| 123 | asm volatile("call __get_user_" #size \ |
| 124 | : "=a" (ret),"=d" (x) \ |
| 125 | : "0" (ptr)) \ |
| 126 | |
Glauber Costa | 865e5b7 | 2008-06-25 11:05:11 -0300 | [diff] [blame] | 127 | /* Careful: we have to cast the result to the type of the pointer |
| 128 | * for sign reasons */ |
| 129 | |
| 130 | /** |
| 131 | * get_user: - Get a simple variable from user space. |
| 132 | * @x: Variable to store result. |
| 133 | * @ptr: Source address, in user space. |
| 134 | * |
| 135 | * Context: User context only. This function may sleep. |
| 136 | * |
| 137 | * This macro copies a single simple variable from user space to kernel |
| 138 | * space. It supports simple types like char and int, but not larger |
| 139 | * data types like structures or arrays. |
| 140 | * |
| 141 | * @ptr must have pointer-to-simple-variable type, and the result of |
| 142 | * dereferencing @ptr must be assignable to @x without a cast. |
| 143 | * |
| 144 | * Returns zero on success, or -EFAULT on error. |
| 145 | * On error, the variable @x is set to zero. |
| 146 | */ |
| 147 | #ifdef CONFIG_X86_32 |
| 148 | #define __get_user_8(__ret_gu, __val_gu, ptr) \ |
| 149 | __get_user_x(X, __ret_gu, __val_gu, ptr) |
| 150 | #else |
| 151 | #define __get_user_8(__ret_gu, __val_gu, ptr) \ |
| 152 | __get_user_x(8, __ret_gu, __val_gu, ptr) |
| 153 | #endif |
| 154 | |
| 155 | #define get_user(x, ptr) \ |
| 156 | ({ \ |
| 157 | int __ret_gu; \ |
| 158 | unsigned long __val_gu; \ |
| 159 | __chk_user_ptr(ptr); \ |
| 160 | switch (sizeof(*(ptr))) { \ |
| 161 | case 1: \ |
| 162 | __get_user_x(1, __ret_gu, __val_gu, ptr); \ |
| 163 | break; \ |
| 164 | case 2: \ |
| 165 | __get_user_x(2, __ret_gu, __val_gu, ptr); \ |
| 166 | break; \ |
| 167 | case 4: \ |
| 168 | __get_user_x(4, __ret_gu, __val_gu, ptr); \ |
| 169 | break; \ |
| 170 | case 8: \ |
| 171 | __get_user_8(__ret_gu, __val_gu, ptr); \ |
| 172 | break; \ |
| 173 | default: \ |
| 174 | __get_user_x(X, __ret_gu, __val_gu, ptr); \ |
| 175 | break; \ |
| 176 | } \ |
| 177 | (x) = (__typeof__(*(ptr)))__val_gu; \ |
| 178 | __ret_gu; \ |
| 179 | }) |
| 180 | |
Glauber Costa | dc70ddf | 2008-06-25 11:48:29 -0300 | [diff] [blame] | 181 | #ifdef CONFIG_X86_32 |
| 182 | #define __put_user_u64(x, addr, err) \ |
| 183 | asm volatile("1: movl %%eax,0(%2)\n" \ |
| 184 | "2: movl %%edx,4(%2)\n" \ |
| 185 | "3:\n" \ |
| 186 | ".section .fixup,\"ax\"\n" \ |
| 187 | "4: movl %3,%0\n" \ |
| 188 | " jmp 3b\n" \ |
| 189 | ".previous\n" \ |
| 190 | _ASM_EXTABLE(1b, 4b) \ |
| 191 | _ASM_EXTABLE(2b, 4b) \ |
| 192 | : "=r" (err) \ |
| 193 | : "A" (x), "r" (addr), "i" (-EFAULT), "0" (err)) |
| 194 | #else |
| 195 | #define __put_user_u64(x, ptr, retval) \ |
| 196 | __put_user_asm(x, ptr, retval, "q", "", "Zr", -EFAULT) |
| 197 | #endif |
| 198 | |
| 199 | #ifdef CONFIG_X86_WP_WORKS_OK |
| 200 | |
| 201 | #define __put_user_size(x, ptr, size, retval, errret) \ |
| 202 | do { \ |
| 203 | retval = 0; \ |
| 204 | __chk_user_ptr(ptr); \ |
| 205 | switch (size) { \ |
| 206 | case 1: \ |
| 207 | __put_user_asm(x, ptr, retval, "b", "b", "iq", errret); \ |
| 208 | break; \ |
| 209 | case 2: \ |
| 210 | __put_user_asm(x, ptr, retval, "w", "w", "ir", errret); \ |
| 211 | break; \ |
| 212 | case 4: \ |
| 213 | __put_user_asm(x, ptr, retval, "l", "k", "ir", errret);\ |
| 214 | break; \ |
| 215 | case 8: \ |
| 216 | __put_user_u64((__typeof__(*ptr))(x), ptr, retval); \ |
| 217 | break; \ |
| 218 | default: \ |
| 219 | __put_user_bad(); \ |
| 220 | } \ |
| 221 | } while (0) |
| 222 | |
| 223 | #else |
| 224 | |
| 225 | #define __put_user_size(x, ptr, size, retval, errret) \ |
| 226 | do { \ |
| 227 | __typeof__(*(ptr))__pus_tmp = x; \ |
| 228 | retval = 0; \ |
| 229 | \ |
| 230 | if (unlikely(__copy_to_user_ll(ptr, &__pus_tmp, size) != 0)) \ |
| 231 | retval = errret; \ |
| 232 | } while (0) |
| 233 | |
| 234 | #endif |
| 235 | |
Glauber Costa | 3f16822 | 2008-06-25 12:48:47 -0300 | [diff] [blame^] | 236 | #ifdef CONFIG_X86_32 |
| 237 | #define __get_user_asm_u64(x, ptr, retval, errret) (x) = __get_user_bad() |
| 238 | #else |
| 239 | #define __get_user_asm_u64(x, ptr, retval, errret) \ |
| 240 | __get_user_asm(x, ptr, retval, "q", "", "=r", errret) |
| 241 | #endif |
| 242 | |
| 243 | #define __get_user_size(x, ptr, size, retval, errret) \ |
| 244 | do { \ |
| 245 | retval = 0; \ |
| 246 | __chk_user_ptr(ptr); \ |
| 247 | switch (size) { \ |
| 248 | case 1: \ |
| 249 | __get_user_asm(x, ptr, retval, "b", "b", "=q", errret); \ |
| 250 | break; \ |
| 251 | case 2: \ |
| 252 | __get_user_asm(x, ptr, retval, "w", "w", "=r", errret); \ |
| 253 | break; \ |
| 254 | case 4: \ |
| 255 | __get_user_asm(x, ptr, retval, "l", "k", "=r", errret); \ |
| 256 | break; \ |
| 257 | case 8: \ |
| 258 | __get_user_asm_u64(x, ptr, retval, errret); \ |
| 259 | break; \ |
| 260 | default: \ |
| 261 | (x) = __get_user_bad(); \ |
| 262 | } \ |
| 263 | } while (0) |
| 264 | |
| 265 | #define __get_user_asm(x, addr, err, itype, rtype, ltype, errret) \ |
| 266 | asm volatile("1: mov"itype" %2,%"rtype"1\n" \ |
| 267 | "2:\n" \ |
| 268 | ".section .fixup,\"ax\"\n" \ |
| 269 | "3: mov %3,%0\n" \ |
| 270 | " xor"itype" %"rtype"1,%"rtype"1\n" \ |
| 271 | " jmp 2b\n" \ |
| 272 | ".previous\n" \ |
| 273 | _ASM_EXTABLE(1b, 3b) \ |
| 274 | : "=r" (err), ltype(x) \ |
| 275 | : "m" (__m(addr)), "i" (errret), "0" (err)) |
| 276 | |
Glauber Costa | dc70ddf | 2008-06-25 11:48:29 -0300 | [diff] [blame] | 277 | #define __put_user_nocheck(x, ptr, size) \ |
| 278 | ({ \ |
| 279 | long __pu_err; \ |
| 280 | __put_user_size((x), (ptr), (size), __pu_err, -EFAULT); \ |
| 281 | __pu_err; \ |
| 282 | }) |
| 283 | |
Glauber Costa | 3f16822 | 2008-06-25 12:48:47 -0300 | [diff] [blame^] | 284 | #define __get_user_nocheck(x, ptr, size) \ |
| 285 | ({ \ |
| 286 | long __gu_err; \ |
| 287 | unsigned long __gu_val; \ |
| 288 | __get_user_size(__gu_val, (ptr), (size), __gu_err, -EFAULT); \ |
| 289 | (x) = (__force __typeof__(*(ptr)))__gu_val; \ |
| 290 | __gu_err; \ |
| 291 | }) |
Glauber Costa | dc70ddf | 2008-06-25 11:48:29 -0300 | [diff] [blame] | 292 | |
| 293 | /* FIXME: this hack is definitely wrong -AK */ |
| 294 | struct __large_struct { unsigned long buf[100]; }; |
| 295 | #define __m(x) (*(struct __large_struct __user *)(x)) |
| 296 | |
| 297 | /* |
| 298 | * Tell gcc we read from memory instead of writing: this is because |
| 299 | * we do not write to any memory gcc knows about, so there are no |
| 300 | * aliasing issues. |
| 301 | */ |
| 302 | #define __put_user_asm(x, addr, err, itype, rtype, ltype, errret) \ |
| 303 | asm volatile("1: mov"itype" %"rtype"1,%2\n" \ |
| 304 | "2:\n" \ |
| 305 | ".section .fixup,\"ax\"\n" \ |
| 306 | "3: mov %3,%0\n" \ |
| 307 | " jmp 2b\n" \ |
| 308 | ".previous\n" \ |
| 309 | _ASM_EXTABLE(1b, 3b) \ |
| 310 | : "=r"(err) \ |
| 311 | : ltype(x), "m" (__m(addr)), "i" (errret), "0" (err)) |
| 312 | |
Glauber Costa | 865e5b7 | 2008-06-25 11:05:11 -0300 | [diff] [blame] | 313 | |
Thomas Gleixner | 96a388d | 2007-10-11 11:20:03 +0200 | [diff] [blame] | 314 | #ifdef CONFIG_X86_32 |
| 315 | # include "uaccess_32.h" |
| 316 | #else |
| 317 | # include "uaccess_64.h" |
| 318 | #endif |
Glauber Costa | ca23386 | 2008-06-13 14:39:25 -0300 | [diff] [blame] | 319 | |
| 320 | #endif |