diff options
Diffstat (limited to 'include')
| -rw-r--r-- | include/asm-generic/uaccess.h | 325 |
1 files changed, 325 insertions, 0 deletions
diff --git a/include/asm-generic/uaccess.h b/include/asm-generic/uaccess.h new file mode 100644 index 000000000000..6d8cab22e294 --- /dev/null +++ b/include/asm-generic/uaccess.h @@ -0,0 +1,325 @@ +#ifndef __ASM_GENERIC_UACCESS_H +#define __ASM_GENERIC_UACCESS_H + +/* + * User space memory access functions, these should work + * on a ny machine that has kernel and user data in the same + * address space, e.g. all NOMMU machines. + */ +#include <linux/sched.h> +#include <linux/mm.h> +#include <linux/string.h> + +#include <asm/segment.h> + +#define MAKE_MM_SEG(s) ((mm_segment_t) { (s) }) + +#ifndef KERNEL_DS +#define KERNEL_DS MAKE_MM_SEG(~0UL) +#endif + +#ifndef USER_DS +#define USER_DS MAKE_MM_SEG(TASK_SIZE - 1) +#endif + +#ifndef get_fs +#define get_ds() (KERNEL_DS) +#define get_fs() (current_thread_info()->addr_limit) + +static inline void set_fs(mm_segment_t fs) +{ + current_thread_info()->addr_limit = fs; +} +#endif + +#define segment_eq(a, b) ((a).seg == (b).seg) + +#define VERIFY_READ 0 +#define VERIFY_WRITE 1 + +#define access_ok(type, addr, size) __access_ok((unsigned long)(addr),(size)) + +/* + * The architecture should really override this if possible, at least + * doing a check on the get_fs() + */ +#ifndef __access_ok +static inline int __access_ok(unsigned long addr, unsigned long size) +{ + return 1; +} +#endif + +/* + * The exception table consists of pairs of addresses: the first is the + * address of an instruction that is allowed to fault, and the second is + * the address at which the program should continue. No registers are + * modified, so it is entirely up to the continuation code to figure out + * what to do. + * + * All the routines below use bits of fixup code that are out of line + * with the main instruction path. This means when everything is well, + * we don't even have to jump over them. Further, they do not intrude + * on our cache or tlb entries. + */ + +struct exception_table_entry +{ + unsigned long insn, fixup; +}; + +/* Returns 0 if exception not found and fixup otherwise. */ +extern unsigned long search_exception_table(unsigned long); + +/* + * architectures with an MMU should override these two + */ +#ifndef __copy_from_user +static inline __must_check long __copy_from_user(void *to, + const void __user * from, unsigned long n) +{ + if (__builtin_constant_p(n)) { + switch(n) { + case 1: + *(u8 *)to = *(u8 __force *)from; + return 0; + case 2: + *(u16 *)to = *(u16 __force *)from; + return 0; + case 4: + *(u32 *)to = *(u32 __force *)from; + return 0; +#ifdef CONFIG_64BIT + case 8: + *(u64 *)to = *(u64 __force *)from; + return 0; +#endif + default: + break; + } + } + + memcpy(to, (const void __force *)from, n); + return 0; +} +#endif + +#ifndef __copy_to_user +static inline __must_check long __copy_to_user(void __user *to, + const void *from, unsigned long n) +{ + if (__builtin_constant_p(n)) { + switch(n) { + case 1: + *(u8 __force *)to = *(u8 *)from; + return 0; + case 2: + *(u16 __force *)to = *(u16 *)from; + return 0; + case 4: + *(u32 __force *)to = *(u32 *)from; + return 0; +#ifdef CONFIG_64BIT + case 8: + *(u64 __force *)to = *(u64 *)from; + return 0; +#endif + default: + break; + } + } + + memcpy((void __force *)to, from, n); + return 0; +} +#endif + +/* + * These are the main single-value transfer routines. They automatically + * use the right size if we just have the right pointer type. + * This version just falls back to copy_{from,to}_user, which should + * provide a fast-path for small values. + */ +#define __put_user(x, ptr) \ +({ \ + __typeof__(*(ptr)) __x = (x); \ + int __pu_err = -EFAULT; \ + __chk_user_ptr(ptr); \ + switch (sizeof (*(ptr))) { \ + case 1: \ + case 2: \ + case 4: \ + case 8: \ + __pu_err = __put_user_fn(sizeof (*(ptr)), \ + ptr, &__x); \ + break; \ + default: \ + __put_user_bad(); \ + break; \ + } \ + __pu_err; \ +}) + +#define put_user(x, ptr) \ +({ \ + might_sleep(); \ + __access_ok(ptr, sizeof (*ptr)) ? \ + __put_user(x, ptr) : \ + -EFAULT; \ +}) + +static inline int __put_user_fn(size_t size, void __user *ptr, void *x) +{ + size = __copy_to_user(ptr, x, size); + return size ? -EFAULT : size; +} + +extern int __put_user_bad(void) __attribute__((noreturn)); + +#define __get_user(x, ptr) \ +({ \ + int __gu_err = -EFAULT; \ + __chk_user_ptr(ptr); \ + switch (sizeof(*(ptr))) { \ + case 1: { \ + unsigned char __x; \ + __gu_err = __get_user_fn(sizeof (*(ptr)), \ + ptr, &__x); \ + (x) = *(__force __typeof__(*(ptr)) *) &__x; \ + break; \ + }; \ + case 2: { \ + unsigned short __x; \ + __gu_err = __get_user_fn(sizeof (*(ptr)), \ + ptr, &__x); \ + (x) = *(__force __typeof__(*(ptr)) *) &__x; \ + break; \ + }; \ + case 4: { \ + unsigned int __x; \ + __gu_err = __get_user_fn(sizeof (*(ptr)), \ + ptr, &__x); \ + (x) = *(__force __typeof__(*(ptr)) *) &__x; \ + break; \ + }; \ + case 8: { \ + unsigned long long __x; \ + __gu_err = __get_user_fn(sizeof (*(ptr)), \ + ptr, &__x); \ + (x) = *(__force __typeof__(*(ptr)) *) &__x; \ + break; \ + }; \ + default: \ + __get_user_bad(); \ + break; \ + } \ + __gu_err; \ +}) + +#define get_user(x, ptr) \ +({ \ + might_sleep(); \ + __access_ok(ptr, sizeof (*ptr)) ? \ + __get_user(x, ptr) : \ + -EFAULT; \ +}) + +static inline int __get_user_fn(size_t size, const void __user *ptr, void *x) +{ + size = __copy_from_user(x, ptr, size); + return size ? -EFAULT : size; +} + +extern int __get_user_bad(void) __attribute__((noreturn)); + +#ifndef __copy_from_user_inatomic +#define __copy_from_user_inatomic __copy_from_user +#endif + +#ifndef __copy_to_user_inatomic +#define __copy_to_user_inatomic __copy_to_user +#endif + +static inline long copy_from_user(void *to, + const void __user * from, unsigned long n) +{ + might_sleep(); + if (__access_ok(from, n)) + return __copy_from_user(to, from, n); + else + return n; +} + +static inline long copy_to_user(void __user *to, + const void *from, unsigned long n) +{ + might_sleep(); + if (__access_ok(to, n)) + return __copy_to_user(to, from, n); + else + return n; +} + +/* + * Copy a null terminated string from userspace. + */ +#ifndef __strncpy_from_user +static inline long +__strncpy_from_user(char *dst, const char __user *src, long count) +{ + char *tmp; + strncpy(dst, (const char __force *)src, count); + for (tmp = dst; *tmp && count > 0; tmp++, count--) + ; + return (tmp - dst); +} +#endif + +static inline long +strncpy_from_user(char *dst, const char __user *src, long count) +{ + if (!__access_ok(src, 1)) + return -EFAULT; + return __strncpy_from_user(dst, src, count); +} + +/* + * Return the size of a string (including the ending 0) + * + * Return 0 on exception, a value greater than N if too long + */ +#ifndef strnlen_user +static inline long strnlen_user(const char __user *src, long n) +{ + return strlen((void * __force)src) + 1; +} +#endif + +static inline long strlen_user(const char __user *src) +{ + return strnlen_user(src, 32767); +} + +/* + * Zero Userspace + */ +#ifndef __clear_user +static inline __must_check unsigned long +__clear_user(void __user *to, unsigned long n) +{ + memset((void __force *)to, 0, n); + return 0; +} +#endif + +static inline __must_check unsigned long +clear_user(void __user *to, unsigned long n) +{ + might_sleep(); + if (!__access_ok(to, n)) + return n; + + return __clear_user(to, n); +} + +#endif /* __ASM_GENERIC_UACCESS_H */ |