#ifndef __i386_UACCESS_H #define __i386_UACCESS_H /* * User space memory access functions */ #include #include #include #include #include #include /* * movsl can be slow when source and dest are not both 8-byte aligned */ #ifdef CONFIG_X86_INTEL_USERCOPY extern struct movsl_mask { int mask; } ____cacheline_aligned_in_smp movsl_mask; #endif extern void __put_user_bad(void); /* * Strange magic calling convention: pointer in %ecx, * value in %eax(:%edx), return value in %eax, no clobbers. */ extern void __put_user_1(void); extern void __put_user_2(void); extern void __put_user_4(void); extern void __put_user_8(void); #define __put_user_x(size, x, ptr, __ret_pu) \ asm volatile("call __put_user_" #size : "=a" (__ret_pu) \ :"0" ((typeof(*(ptr)))(x)), "c" (ptr) : "ebx") #define __put_user_8(x, ptr, __ret_pu) \ asm volatile("call __put_user_8" : "=a" (__ret_pu) \ : "A" ((typeof(*(ptr)))(x)), "c" (ptr) : "ebx") /** * put_user: - Write a simple value into user space. * @x: Value to copy to user space. * @ptr: Destination address, in user space. * * Context: User context only. This function may sleep. * * This macro copies a single simple value from kernel space to user * space. It supports simple types like char and int, but not larger * data types like structures or arrays. * * @ptr must have pointer-to-simple-variable type, and @x must be assignable * to the result of dereferencing @ptr. * * Returns zero on success, or -EFAULT on error. */ #ifdef CONFIG_X86_WP_WORKS_OK #define put_user(x, ptr) \ ({ \ int __ret_pu; \ __typeof__(*(ptr)) __pu_val; \ __chk_user_ptr(ptr); \ __pu_val = x; \ switch (sizeof(*(ptr))) { \ case 1: \ __put_user_x(1, __pu_val, ptr, __ret_pu); \ break; \ case 2: \ __put_user_x(2, __pu_val, ptr, __ret_pu); \ break; \ case 4: \ __put_user_x(4, __pu_val, ptr, __ret_pu); \ break; \ case 8: \ __put_user_8(__pu_val, ptr, __ret_pu); \ break; \ default: \ __put_user_x(X, __pu_val, ptr, __ret_pu); \ break; \ } \ __ret_pu; \ }) #else #define put_user(x, ptr) \ ({ \ int __ret_pu; \ __typeof__(*(ptr))__pus_tmp = x; \ __ret_pu = 0; \ if (unlikely(__copy_to_user_ll(ptr, &__pus_tmp, \ sizeof(*(ptr))) != 0)) \ __ret_pu = -EFAULT; \ __ret_pu; \ }) #endif /** * __get_user: - Get a simple variable from user space, with less checking. * @x: Variable to store result. * @ptr: Source address, in user space. * * Context: User context only. This function may sleep. * * This macro copies a single simple variable from user space to kernel * space. It supports simple types like char and int, but not larger * data types like structures or arrays. * * @ptr must have pointer-to-simple-variable type, and the result of * dereferencing @ptr must be assignable to @x without a cast. * * Caller must check the pointer with access_ok() before calling this * function. * * Returns zero on success, or -EFAULT on error. * On error, the variable @x is set to zero. */ #define __get_user(x, ptr) \ __get_user_nocheck((x), (ptr), sizeof(*(ptr))) /** * __put_user: - Write a simple value into user space, with less checking. * @x: Value to copy to user space. * @ptr: Destination address, in user space. * * Context: User context only. This function may sleep. * * This macro copies a single simple value from kernel space to user * space. It supports simple types like char and int, but not larger * data types like structures or arrays. * * @ptr must have pointer-to-simple-variable type, and @x must be assignable * to the result of dereferencing @ptr. * * Caller must check the pointer with access_ok() before calling this * function. * * Returns zero on success, or -EFAULT on error. */ #define __put_user(x, ptr) \ __put_user_nocheck((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr))) unsigned long __must_check __copy_to_user_ll (void __user *to, const void *from, unsigned long n); unsigned long __must_check __copy_from_user_ll (void *to, const void __user *from, unsigned long n); unsigned long __must_check __copy_from_user_ll_nozero (void *to, const void __user *from, unsigned long n); unsigned long __must_check __copy_from_user_ll_nocache (void *to, const void __user *from, unsigned long n); unsigned long __must_check __copy_from_user_ll_nocache_nozero (void *to, const void __user *from, unsigned long n); /** * __copy_to_user_inatomic: - Copy a block of data into user space, with less checking. * @to: Destination address, in user space. * @from: Source address, in kernel space. * @n: Number of bytes to copy. * * Context: User context only. * * Copy data from kernel space to user space. Caller must check * the specified block with access_ok() before calling this function. * The caller should also make sure he pins the user space address * so that the we don't result in page fault and sleep. * * Here we special-case 1, 2 and 4-byte copy_*_user invocations. On a fault * we return the initial request size (1, 2 or 4), as copy_*_user should do. * If a store crosses a page boundary and gets a fault, the x86 will not write * anything, so this is accurate. */ static __always_inline unsigned long __must_check __copy_to_user_inatomic(void __user *to, const void *from, unsigned long n) { if (__builtin_constant_p(n)) { unsigned long ret; switch (n) { case 1: __put_user_size(*(u8 *)from, (u8 __user *)to, 1, ret, 1); return ret; case 2: __put_user_size(*(u16 *)from, (u16 __user *)to, 2, ret, 2); return ret; case 4: __put_user_size(*(u32 *)from, (u32 __user *)to, 4, ret, 4); return ret; } } return __copy_to_user_ll(to, from, n); } /** * __copy_to_user: - Copy a block of data into user space, with less checking. * @to: Destination address, in user space. * @from: Source address, in kernel space. * @n: Number of bytes to copy. * * Context: User context only. This function may sleep. * * Copy data from kernel space to user space. Caller must check * the specified block with access_ok() before calling this function. * * Returns number of bytes that could not be copied. * On success, this will be zero. */ static __always_inline unsigned long __must_check __copy_to_user(void __user *to, const void *from, unsigned long n) { might_sleep(); return __copy_to_user_inatomic(to, from, n); } static __always_inline unsigned long __copy_from_user_inatomic(void *to, const void __user *from, unsigned long n) { /* Avoid zeroing the tail if the copy fails.. * If 'n' is constant and 1, 2, or 4, we do still zero on a failure, * but as the zeroing behaviour is only significant when n is not * constant, that shouldn't be a problem. */ if (__builtin_constant_p(n)) { unsigned long ret; switch (n) { case 1: __get_user_size(*(u8 *)to, from, 1, ret, 1); return ret; case 2: __get_user_size(*(u16 *)to, from, 2, ret, 2); return ret; case 4: __get_user_size(*(u32 *)to, from, 4, ret, 4); return ret; } } return __copy_from_user_ll_nozero(to, from, n); } /** * __copy_from_user: - Copy a block of data from user space, with less checking. * @to: Destination address, in kernel space. * @from: Source address, in user space. * @n: Number of bytes to copy. * * Context: User context only. This function may sleep. * * Copy data from user space to kernel space. Caller must check * the specified block with access_ok() before calling this function. * * Returns number of bytes that could not be copied. * On success, this will be zero. * * If some data could not be copied, this function will pad the copied * data to the requested size using zero bytes. * * An alternate version - __copy_from_user_inatomic() - may be called from * atomic context and will fail rather than sleep. In this case the * uncopied bytes will *NOT* be padded with zeros. See fs/filemap.h * for explanation of why this is needed. */ static __always_inline unsigned long __copy_from_user(void *to, const void __user *from, unsigned long n) { might_sleep(); if (__builtin_constant_p(n)) { unsigned long ret; switch (n) { case 1: __get_user_size(*(u8 *)to, from, 1, ret, 1); return ret; case 2: __get_user_size(*(u16 *)to, from, 2, ret, 2); return ret; case 4: __get_user_size(*(u32 *)to, from, 4, ret, 4); return ret; } } return __copy_from_user_ll(to, from, n); } #define ARCH_HAS_NOCACHE_UACCESS static __always_inline unsigned long __copy_from_user_nocache(void *to, const void __user *from, unsigned long n) { might_sleep(); if (__builtin_constant_p(n)) { unsigned long ret; switch (n) { case 1: __get_user_size(*(u8 *)to, from, 1, ret, 1); return ret; case 2: __get_user_size(*(u16 *)to, from, 2, ret, 2); return ret; case 4: __get_user_size(*(u32 *)to, from, 4, ret, 4); return ret; } } return __copy_from_user_ll_nocache(to, from, n); } static __always_inline unsigned long __copy_from_user_inatomic_nocache(void *to, const void __user *from, unsigned long n) { return __copy_from_user_ll_nocache_nozero(to, from, n); } unsigned long __must_check copy_to_user(void __user *to, const void *from, unsigned long n); unsigned long __must_check copy_from_user(void *to, const void __user *from, unsigned long n); long __must_check strncpy_from_user(char *dst, const char __user *src, long count); long __must_check __strncpy_from_user(char *dst, const char __user *src, long count); /** * strlen_user: - Get the size of a string in user space. * @str: The string to measure. * * Context: User context only. This function may sleep. * * Get the size of a NUL-terminated string in user space. * * Returns the size of the string INCLUDING the terminating NUL. * On exception, returns 0. * * If there is a limit on the length of a valid string, you may wish to * consider using strnlen_user() instead. */ #define strlen_user(str) strnlen_user(str, LONG_MAX) long strnlen_user(const char __user *str, long n); unsigned long __must_check clear_user(void __user *mem, unsigned long len); unsigned long __must_check __clear_user(void __user *mem, unsigned long len); #endif /* __i386_UACCESS_H */