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Diffstat (limited to '')
| -rw-r--r-- | include/asm-generic/uaccess.h | 228 |
1 files changed, 228 insertions, 0 deletions
diff --git a/include/asm-generic/uaccess.h b/include/asm-generic/uaccess.h new file mode 100644 index 000000000..6b2e63df2 --- /dev/null +++ b/include/asm-generic/uaccess.h @@ -0,0 +1,228 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __ASM_GENERIC_UACCESS_H +#define __ASM_GENERIC_UACCESS_H + +/* + * User space memory access functions, these should work + * on any machine that has kernel and user data in the same + * address space, e.g. all NOMMU machines. + */ +#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 + +#ifndef segment_eq +#define segment_eq(a, b) ((a).seg == (b).seg) +#endif + +#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 + +/* + * 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) \ +({ \ + void __user *__p = (ptr); \ + might_fault(); \ + access_ok(VERIFY_WRITE, __p, sizeof(*ptr)) ? \ + __put_user((x), ((__typeof__(*(ptr)) __user *)__p)) : \ + -EFAULT; \ +}) + +#ifndef __put_user_fn + +static inline int __put_user_fn(size_t size, void __user *ptr, void *x) +{ + return unlikely(raw_copy_to_user(ptr, x, size)) ? -EFAULT : 0; +} + +#define __put_user_fn(sz, u, k) __put_user_fn(sz, u, k) + +#endif + +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 = 0; \ + __gu_err = __get_user_fn(sizeof (*(ptr)), \ + ptr, &__x); \ + (x) = *(__force __typeof__(*(ptr)) *) &__x; \ + break; \ + }; \ + case 2: { \ + unsigned short __x = 0; \ + __gu_err = __get_user_fn(sizeof (*(ptr)), \ + ptr, &__x); \ + (x) = *(__force __typeof__(*(ptr)) *) &__x; \ + break; \ + }; \ + case 4: { \ + unsigned int __x = 0; \ + __gu_err = __get_user_fn(sizeof (*(ptr)), \ + ptr, &__x); \ + (x) = *(__force __typeof__(*(ptr)) *) &__x; \ + break; \ + }; \ + case 8: { \ + unsigned long long __x = 0; \ + __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) \ +({ \ + const void __user *__p = (ptr); \ + might_fault(); \ + access_ok(VERIFY_READ, __p, sizeof(*ptr)) ? \ + __get_user((x), (__typeof__(*(ptr)) __user *)__p) :\ + ((x) = (__typeof__(*(ptr)))0,-EFAULT); \ +}) + +#ifndef __get_user_fn +static inline int __get_user_fn(size_t size, const void __user *ptr, void *x) +{ + return unlikely(raw_copy_from_user(x, ptr, size)) ? -EFAULT : 0; +} + +#define __get_user_fn(sz, u, k) __get_user_fn(sz, u, k) + +#endif + +extern int __get_user_bad(void) __attribute__((noreturn)); + +/* + * 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(VERIFY_READ, 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 +#define __strnlen_user(s, n) (strnlen((s), (n)) + 1) +#endif + +/* + * Unlike strnlen, strnlen_user includes the nul terminator in + * its returned count. Callers should check for a returned value + * greater than N as an indication the string is too long. + */ +static inline long strnlen_user(const char __user *src, long n) +{ + if (!access_ok(VERIFY_READ, src, 1)) + return 0; + return __strnlen_user(src, n); +} + +/* + * 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_fault(); + if (!access_ok(VERIFY_WRITE, to, n)) + return n; + + return __clear_user(to, n); +} + +#include <asm/extable.h> + +#endif /* __ASM_GENERIC_UACCESS_H */ |