diff options
Diffstat (limited to 'arch/x86/include/asm/uaccess.h')
| -rw-r--r-- | arch/x86/include/asm/uaccess.h | 55 |
1 files changed, 21 insertions, 34 deletions
diff --git a/arch/x86/include/asm/uaccess.h b/arch/x86/include/asm/uaccess.h index 1709801d18e..5ee26875bae 100644 --- a/arch/x86/include/asm/uaccess.h +++ b/arch/x86/include/asm/uaccess.h @@ -125,13 +125,12 @@ extern int __get_user_4(void); extern int __get_user_8(void); extern int __get_user_bad(void); -#define __get_user_x(size, ret, x, ptr) \ - asm volatile("call __get_user_" #size \ - : "=a" (ret), "=d" (x) \ - : "0" (ptr)) \ - -/* Careful: we have to cast the result to the type of the pointer - * for sign reasons */ +/* + * This is a type: either unsigned long, if the argument fits into + * that type, or otherwise unsigned long long. + */ +#define __inttype(x) \ +__typeof__(__builtin_choose_expr(sizeof(x) > sizeof(0UL), 0ULL, 0UL)) /** * get_user: - Get a simple variable from user space. @@ -150,38 +149,26 @@ extern int __get_user_bad(void); * Returns zero on success, or -EFAULT on error. * On error, the variable @x is set to zero. */ -#ifdef CONFIG_X86_32 -#define __get_user_8(__ret_gu, __val_gu, ptr) \ - __get_user_x(X, __ret_gu, __val_gu, ptr) -#else -#define __get_user_8(__ret_gu, __val_gu, ptr) \ - __get_user_x(8, __ret_gu, __val_gu, ptr) -#endif - +/* + * Careful: we have to cast the result to the type of the pointer + * for sign reasons. + * + * The use of %edx as the register specifier is a bit of a + * simplification, as gcc only cares about it as the starting point + * and not size: for a 64-bit value it will use %ecx:%edx on 32 bits + * (%ecx being the next register in gcc's x86 register sequence), and + * %rdx on 64 bits. + */ #define get_user(x, ptr) \ ({ \ int __ret_gu; \ - unsigned long __val_gu; \ + register __inttype(*(ptr)) __val_gu asm("%edx"); \ __chk_user_ptr(ptr); \ might_fault(); \ - switch (sizeof(*(ptr))) { \ - case 1: \ - __get_user_x(1, __ret_gu, __val_gu, ptr); \ - break; \ - case 2: \ - __get_user_x(2, __ret_gu, __val_gu, ptr); \ - break; \ - case 4: \ - __get_user_x(4, __ret_gu, __val_gu, ptr); \ - break; \ - case 8: \ - __get_user_8(__ret_gu, __val_gu, ptr); \ - break; \ - default: \ - __get_user_x(X, __ret_gu, __val_gu, ptr); \ - break; \ - } \ - (x) = (__typeof__(*(ptr)))__val_gu; \ + asm volatile("call __get_user_%P3" \ + : "=a" (__ret_gu), "=r" (__val_gu) \ + : "0" (ptr), "i" (sizeof(*(ptr)))); \ + (x) = (__typeof__(*(ptr))) __val_gu; \ __ret_gu; \ }) |