1/* 2 * User address space access functions. 3 * The non inlined parts of asm-i386/uaccess.h are here. 4 * 5 * Copyright 1997 Andi Kleen <ak@muc.de> 6 * Copyright 1997 Linus Torvalds 7 */ 8#include <linux/config.h> 9#include <asm/uaccess.h> 10#include <asm/mmx.h> 11 12#ifdef CONFIG_X86_USE_3DNOW_AND_WORKS 13 14unsigned long 15__generic_copy_to_user(void *to, const void *from, unsigned long n) 16{ 17 if (access_ok(VERIFY_WRITE, to, n)) 18 { 19 if(n<512) 20 __copy_user(to,from,n); 21 else 22 mmx_copy_user(to,from,n); 23 } 24 return n; 25} 26 27unsigned long 28__generic_copy_from_user(void *to, const void *from, unsigned long n) 29{ 30 if (access_ok(VERIFY_READ, from, n)) 31 { 32 if(n<512) 33 __copy_user_zeroing(to,from,n); 34 else 35 mmx_copy_user_zeroing(to, from, n); 36 } 37 else 38 memset(to, 0, n); 39 return n; 40} 41 42#else 43 44unsigned long 45__generic_copy_to_user(void *to, const void *from, unsigned long n) 46{ 47 prefetch(from); 48 if (access_ok(VERIFY_WRITE, to, n)) 49 __copy_user(to,from,n); 50 return n; 51} 52 53unsigned long 54__generic_copy_from_user(void *to, const void *from, unsigned long n) 55{ 56 prefetchw(to); 57 if (access_ok(VERIFY_READ, from, n)) 58 __copy_user_zeroing(to,from,n); 59 else 60 memset(to, 0, n); 61 return n; 62} 63 64#endif 65 66/* 67 * Copy a null terminated string from userspace. 68 */ 69 70#define __do_strncpy_from_user(dst,src,count,res) \ 71do { \ 72 int __d0, __d1, __d2; \ 73 __asm__ __volatile__( \ 74 " testl %1,%1\n" \ 75 " jz 2f\n" \ 76 "0: lodsb\n" \ 77 " stosb\n" \ 78 " testb %%al,%%al\n" \ 79 " jz 1f\n" \ 80 " decl %1\n" \ 81 " jnz 0b\n" \ 82 "1: subl %1,%0\n" \ 83 "2:\n" \ 84 ".section .fixup,\"ax\"\n" \ 85 "3: movl %5,%0\n" \ 86 " jmp 2b\n" \ 87 ".previous\n" \ 88 ".section __ex_table,\"a\"\n" \ 89 " .align 4\n" \ 90 " .long 0b,3b\n" \ 91 ".previous" \ 92 : "=d"(res), "=c"(count), "=&a" (__d0), "=&S" (__d1), \ 93 "=&D" (__d2) \ 94 : "i"(-EFAULT), "0"(count), "1"(count), "3"(src), "4"(dst) \ 95 : "memory"); \ 96} while (0) 97 98long 99__strncpy_from_user(char *dst, const char *src, long count) 100{ 101 long res; 102 __do_strncpy_from_user(dst, src, count, res); 103 return res; 104} 105 106long 107strncpy_from_user(char *dst, const char *src, long count) 108{ 109 long res = -EFAULT; 110 if (access_ok(VERIFY_READ, src, 1)) 111 __do_strncpy_from_user(dst, src, count, res); 112 return res; 113} 114 115 116/* 117 * Zero Userspace 118 */ 119 120#define __do_clear_user(addr,size) \ 121do { \ 122 int __d0; \ 123 __asm__ __volatile__( \ 124 "0: rep; stosl\n" \ 125 " movl %2,%0\n" \ 126 "1: rep; stosb\n" \ 127 "2:\n" \ 128 ".section .fixup,\"ax\"\n" \ 129 "3: lea 0(%2,%0,4),%0\n" \ 130 " jmp 2b\n" \ 131 ".previous\n" \ 132 ".section __ex_table,\"a\"\n" \ 133 " .align 4\n" \ 134 " .long 0b,3b\n" \ 135 " .long 1b,2b\n" \ 136 ".previous" \ 137 : "=&c"(size), "=&D" (__d0) \ 138 : "r"(size & 3), "0"(size / 4), "1"(addr), "a"(0)); \ 139} while (0) 140 141unsigned long 142clear_user(void *to, unsigned long n) 143{ 144 if (access_ok(VERIFY_WRITE, to, n)) 145 __do_clear_user(to, n); 146 return n; 147} 148 149unsigned long 150__clear_user(void *to, unsigned long n) 151{ 152 __do_clear_user(to, n); 153 return n; 154} 155 156/* 157 * Return the size of a string (including the ending 0) 158 * 159 * Return 0 on exception, a value greater than N if too long 160 */ 161 162long strnlen_user(const char *s, long n) 163{ 164 unsigned long mask = -__addr_ok(s); 165 unsigned long res, tmp; 166 167 __asm__ __volatile__( 168 " testl %0, %0\n" 169 " jz 3f\n" 170 " andl %0,%%ecx\n" 171 "0: repne; scasb\n" 172 " setne %%al\n" 173 " subl %%ecx,%0\n" 174 " addl %0,%%eax\n" 175 "1:\n" 176 ".section .fixup,\"ax\"\n" 177 "2: xorl %%eax,%%eax\n" 178 " jmp 1b\n" 179 "3: movb $1,%%al\n" 180 " jmp 1b\n" 181 ".previous\n" 182 ".section __ex_table,\"a\"\n" 183 " .align 4\n" 184 " .long 0b,2b\n" 185 ".previous" 186 :"=r" (n), "=D" (s), "=a" (res), "=c" (tmp) 187 :"0" (n), "1" (s), "2" (0), "3" (mask) 188 :"cc"); 189 return res & mask; 190} 191