diff options
Diffstat (limited to 'arch/x86/lib/usercopy_64.c')
| -rw-r--r-- | arch/x86/lib/usercopy_64.c | 166 |
1 files changed, 166 insertions, 0 deletions
diff --git a/arch/x86/lib/usercopy_64.c b/arch/x86/lib/usercopy_64.c new file mode 100644 index 00000000000..893d43f838c --- /dev/null +++ b/arch/x86/lib/usercopy_64.c @@ -0,0 +1,166 @@ +/* + * User address space access functions. + * + * Copyright 1997 Andi Kleen <ak@muc.de> + * Copyright 1997 Linus Torvalds + * Copyright 2002 Andi Kleen <ak@suse.de> + */ +#include <linux/module.h> +#include <asm/uaccess.h> + +/* + * Copy a null terminated string from userspace. + */ + +#define __do_strncpy_from_user(dst,src,count,res) \ +do { \ + long __d0, __d1, __d2; \ + might_sleep(); \ + __asm__ __volatile__( \ + " testq %1,%1\n" \ + " jz 2f\n" \ + "0: lodsb\n" \ + " stosb\n" \ + " testb %%al,%%al\n" \ + " jz 1f\n" \ + " decq %1\n" \ + " jnz 0b\n" \ + "1: subq %1,%0\n" \ + "2:\n" \ + ".section .fixup,\"ax\"\n" \ + "3: movq %5,%0\n" \ + " jmp 2b\n" \ + ".previous\n" \ + ".section __ex_table,\"a\"\n" \ + " .align 8\n" \ + " .quad 0b,3b\n" \ + ".previous" \ + : "=r"(res), "=c"(count), "=&a" (__d0), "=&S" (__d1), \ + "=&D" (__d2) \ + : "i"(-EFAULT), "0"(count), "1"(count), "3"(src), "4"(dst) \ + : "memory"); \ +} while (0) + +long +__strncpy_from_user(char *dst, const char __user *src, long count) +{ + long res; + __do_strncpy_from_user(dst, src, count, res); + return res; +} +EXPORT_SYMBOL(__strncpy_from_user); + +long +strncpy_from_user(char *dst, const char __user *src, long count) +{ + long res = -EFAULT; + if (access_ok(VERIFY_READ, src, 1)) + return __strncpy_from_user(dst, src, count); + return res; +} +EXPORT_SYMBOL(strncpy_from_user); + +/* + * Zero Userspace + */ + +unsigned long __clear_user(void __user *addr, unsigned long size) +{ + long __d0; + might_sleep(); + /* no memory constraint because it doesn't change any memory gcc knows + about */ + asm volatile( + " testq %[size8],%[size8]\n" + " jz 4f\n" + "0: movq %[zero],(%[dst])\n" + " addq %[eight],%[dst]\n" + " decl %%ecx ; jnz 0b\n" + "4: movq %[size1],%%rcx\n" + " testl %%ecx,%%ecx\n" + " jz 2f\n" + "1: movb %b[zero],(%[dst])\n" + " incq %[dst]\n" + " decl %%ecx ; jnz 1b\n" + "2:\n" + ".section .fixup,\"ax\"\n" + "3: lea 0(%[size1],%[size8],8),%[size8]\n" + " jmp 2b\n" + ".previous\n" + ".section __ex_table,\"a\"\n" + " .align 8\n" + " .quad 0b,3b\n" + " .quad 1b,2b\n" + ".previous" + : [size8] "=c"(size), [dst] "=&D" (__d0) + : [size1] "r"(size & 7), "[size8]" (size / 8), "[dst]"(addr), + [zero] "r" (0UL), [eight] "r" (8UL)); + return size; +} +EXPORT_SYMBOL(__clear_user); + +unsigned long clear_user(void __user *to, unsigned long n) +{ + if (access_ok(VERIFY_WRITE, to, n)) + return __clear_user(to, n); + return n; +} +EXPORT_SYMBOL(clear_user); + +/* + * Return the size of a string (including the ending 0) + * + * Return 0 on exception, a value greater than N if too long + */ + +long __strnlen_user(const char __user *s, long n) +{ + long res = 0; + char c; + + while (1) { + if (res>n) + return n+1; + if (__get_user(c, s)) + return 0; + if (!c) + return res+1; + res++; + s++; + } +} +EXPORT_SYMBOL(__strnlen_user); + +long strnlen_user(const char __user *s, long n) +{ + if (!access_ok(VERIFY_READ, s, n)) + return 0; + return __strnlen_user(s, n); +} +EXPORT_SYMBOL(strnlen_user); + +long strlen_user(const char __user *s) +{ + long res = 0; + char c; + + for (;;) { + if (get_user(c, s)) + return 0; + if (!c) + return res+1; + res++; + s++; + } +} +EXPORT_SYMBOL(strlen_user); + +unsigned long copy_in_user(void __user *to, const void __user *from, unsigned len) +{ + if (access_ok(VERIFY_WRITE, to, len) && access_ok(VERIFY_READ, from, len)) { + return copy_user_generic((__force void *)to, (__force void *)from, len); + } + return len; +} +EXPORT_SYMBOL(copy_in_user); + |