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Diffstat (limited to 'arch/xtensa/include/asm/uaccess.h')
| -rw-r--r-- | arch/xtensa/include/asm/uaccess.h | 320 |
1 files changed, 320 insertions, 0 deletions
diff --git a/arch/xtensa/include/asm/uaccess.h b/arch/xtensa/include/asm/uaccess.h new file mode 100644 index 000000000..5c9fb8005 --- /dev/null +++ b/arch/xtensa/include/asm/uaccess.h @@ -0,0 +1,320 @@ +/* + * include/asm-xtensa/uaccess.h + * + * User space memory access functions + * + * These routines provide basic accessing functions to the user memory + * space for the kernel. This header file provides functions such as: + * + * This file is subject to the terms and conditions of the GNU General Public + * License. See the file "COPYING" in the main directory of this archive + * for more details. + * + * Copyright (C) 2001 - 2005 Tensilica Inc. + */ + +#ifndef _XTENSA_UACCESS_H +#define _XTENSA_UACCESS_H + +#include <linux/prefetch.h> +#include <asm/types.h> +#include <asm/extable.h> + +/* + * The fs value determines whether argument validity checking should + * be performed or not. If get_fs() == USER_DS, checking is + * performed, with get_fs() == KERNEL_DS, checking is bypassed. + * + * For historical reasons (Data Segment Register?), these macros are + * grossly misnamed. + */ + +#define KERNEL_DS ((mm_segment_t) { 0 }) +#define USER_DS ((mm_segment_t) { 1 }) + +#define get_fs() (current->thread.current_ds) +#define set_fs(val) (current->thread.current_ds = (val)) + +#define uaccess_kernel() (get_fs().seg == KERNEL_DS.seg) + +#define __kernel_ok (uaccess_kernel()) +#define __user_ok(addr, size) \ + (((size) <= TASK_SIZE)&&((addr) <= TASK_SIZE-(size))) +#define __access_ok(addr, size) (__kernel_ok || __user_ok((addr), (size))) +#define access_ok(addr, size) __access_ok((unsigned long)(addr), (size)) + +#define user_addr_max() (uaccess_kernel() ? ~0UL : TASK_SIZE) + +/* + * These are the main single-value transfer routines. They + * automatically use the right size if we just have the right pointer + * type. + * + * This gets kind of ugly. We want to return _two_ values in + * "get_user()" and yet we don't want to do any pointers, because that + * is too much of a performance impact. Thus we have a few rather ugly + * macros here, and hide all the uglyness from the user. + * + * Careful to not + * (a) re-use the arguments for side effects (sizeof is ok) + * (b) require any knowledge of processes at this stage + */ +#define put_user(x, ptr) __put_user_check((x), (ptr), sizeof(*(ptr))) +#define get_user(x, ptr) __get_user_check((x), (ptr), sizeof(*(ptr))) + +/* + * The "__xxx" versions of the user access functions are versions that + * do not verify the address space, that must have been done previously + * with a separate "access_ok()" call (this is used when we do multiple + * accesses to the same area of user memory). + */ +#define __put_user(x, ptr) __put_user_nocheck((x), (ptr), sizeof(*(ptr))) +#define __get_user(x, ptr) __get_user_nocheck((x), (ptr), sizeof(*(ptr))) + + +extern long __put_user_bad(void); + +#define __put_user_nocheck(x, ptr, size) \ +({ \ + long __pu_err; \ + __put_user_size((x), (ptr), (size), __pu_err); \ + __pu_err; \ +}) + +#define __put_user_check(x, ptr, size) \ +({ \ + long __pu_err = -EFAULT; \ + __typeof__(*(ptr)) __user *__pu_addr = (ptr); \ + if (access_ok(__pu_addr, size)) \ + __put_user_size((x), __pu_addr, (size), __pu_err); \ + __pu_err; \ +}) + +#define __put_user_size(x, ptr, size, retval) \ +do { \ + int __cb; \ + retval = 0; \ + switch (size) { \ + case 1: __put_user_asm(x, ptr, retval, 1, "s8i", __cb); break; \ + case 2: __put_user_asm(x, ptr, retval, 2, "s16i", __cb); break; \ + case 4: __put_user_asm(x, ptr, retval, 4, "s32i", __cb); break; \ + case 8: { \ + __typeof__(*ptr) __v64 = x; \ + retval = __copy_to_user(ptr, &__v64, 8) ? -EFAULT : 0; \ + break; \ + } \ + default: __put_user_bad(); \ + } \ +} while (0) + + +/* + * Consider a case of a user single load/store would cause both an + * unaligned exception and an MMU-related exception (unaligned + * exceptions happen first): + * + * User code passes a bad variable ptr to a system call. + * Kernel tries to access the variable. + * Unaligned exception occurs. + * Unaligned exception handler tries to make aligned accesses. + * Double exception occurs for MMU-related cause (e.g., page not mapped). + * do_page_fault() thinks the fault address belongs to the kernel, not the + * user, and panics. + * + * The kernel currently prohibits user unaligned accesses. We use the + * __check_align_* macros to check for unaligned addresses before + * accessing user space so we don't crash the kernel. Both + * __put_user_asm and __get_user_asm use these alignment macros, so + * macro-specific labels such as 0f, 1f, %0, %2, and %3 must stay in + * sync. + */ + +#define __check_align_1 "" + +#define __check_align_2 \ + " _bbci.l %[mem] * 0, 1f \n" \ + " movi %[err], %[efault] \n" \ + " _j 2f \n" + +#define __check_align_4 \ + " _bbsi.l %[mem] * 0, 0f \n" \ + " _bbci.l %[mem] * 0 + 1, 1f \n" \ + "0: movi %[err], %[efault] \n" \ + " _j 2f \n" + + +/* + * We don't tell gcc that we are accessing memory, but this is OK + * because we do not write to any memory gcc knows about, so there + * are no aliasing issues. + * + * WARNING: If you modify this macro at all, verify that the + * __check_align_* macros still work. + */ +#define __put_user_asm(x_, addr_, err_, align, insn, cb)\ +__asm__ __volatile__( \ + __check_align_##align \ + "1: "insn" %[x], %[mem] \n" \ + "2: \n" \ + " .section .fixup,\"ax\" \n" \ + " .align 4 \n" \ + " .literal_position \n" \ + "5: \n" \ + " movi %[tmp], 2b \n" \ + " movi %[err], %[efault] \n" \ + " jx %[tmp] \n" \ + " .previous \n" \ + " .section __ex_table,\"a\" \n" \ + " .long 1b, 5b \n" \ + " .previous" \ + :[err] "+r"(err_), [tmp] "=r"(cb), [mem] "=m"(*(addr_)) \ + :[x] "r"(x_), [efault] "i"(-EFAULT)) + +#define __get_user_nocheck(x, ptr, size) \ +({ \ + long __gu_err; \ + __get_user_size((x), (ptr), (size), __gu_err); \ + __gu_err; \ +}) + +#define __get_user_check(x, ptr, size) \ +({ \ + long __gu_err = -EFAULT; \ + const __typeof__(*(ptr)) __user *__gu_addr = (ptr); \ + if (access_ok(__gu_addr, size)) \ + __get_user_size((x), __gu_addr, (size), __gu_err); \ + else \ + (x) = (__typeof__(*(ptr)))0; \ + __gu_err; \ +}) + +extern long __get_user_bad(void); + +#define __get_user_size(x, ptr, size, retval) \ +do { \ + int __cb; \ + retval = 0; \ + switch (size) { \ + case 1: __get_user_asm(x, ptr, retval, 1, "l8ui", __cb); break;\ + case 2: __get_user_asm(x, ptr, retval, 2, "l16ui", __cb); break;\ + case 4: __get_user_asm(x, ptr, retval, 4, "l32i", __cb); break;\ + case 8: { \ + u64 __x; \ + if (unlikely(__copy_from_user(&__x, ptr, 8))) { \ + retval = -EFAULT; \ + (x) = (__typeof__(*(ptr)))0; \ + } else { \ + (x) = *(__force __typeof__(*(ptr)) *)&__x; \ + } \ + break; \ + } \ + default: \ + (x) = (__typeof__(*(ptr)))0; \ + __get_user_bad(); \ + } \ +} while (0) + + +/* + * WARNING: If you modify this macro at all, verify that the + * __check_align_* macros still work. + */ +#define __get_user_asm(x_, addr_, err_, align, insn, cb) \ +do { \ + u32 __x = 0; \ + __asm__ __volatile__( \ + __check_align_##align \ + "1: "insn" %[x], %[mem] \n" \ + "2: \n" \ + " .section .fixup,\"ax\" \n" \ + " .align 4 \n" \ + " .literal_position \n" \ + "5: \n" \ + " movi %[tmp], 2b \n" \ + " movi %[err], %[efault] \n" \ + " jx %[tmp] \n" \ + " .previous \n" \ + " .section __ex_table,\"a\" \n" \ + " .long 1b, 5b \n" \ + " .previous" \ + :[err] "+r"(err_), [tmp] "=r"(cb), [x] "+r"(__x) \ + :[mem] "m"(*(addr_)), [efault] "i"(-EFAULT)); \ + (x_) = (__force __typeof__(*(addr_)))__x; \ +} while (0) + + +/* + * Copy to/from user space + */ + +extern unsigned __xtensa_copy_user(void *to, const void *from, unsigned n); + +static inline unsigned long +raw_copy_from_user(void *to, const void __user *from, unsigned long n) +{ + prefetchw(to); + return __xtensa_copy_user(to, (__force const void *)from, n); +} +static inline unsigned long +raw_copy_to_user(void __user *to, const void *from, unsigned long n) +{ + prefetch(from); + return __xtensa_copy_user((__force void *)to, from, n); +} +#define INLINE_COPY_FROM_USER +#define INLINE_COPY_TO_USER + +/* + * We need to return the number of bytes not cleared. Our memset() + * returns zero if a problem occurs while accessing user-space memory. + * In that event, return no memory cleared. Otherwise, zero for + * success. + */ + +static inline unsigned long +__xtensa_clear_user(void __user *addr, unsigned long size) +{ + if (!__memset((void __force *)addr, 0, size)) + return size; + return 0; +} + +static inline unsigned long +clear_user(void __user *addr, unsigned long size) +{ + if (access_ok(addr, size)) + return __xtensa_clear_user(addr, size); + return size ? -EFAULT : 0; +} + +#define __clear_user __xtensa_clear_user + + +#ifndef CONFIG_GENERIC_STRNCPY_FROM_USER + +extern long __strncpy_user(char *dst, const char __user *src, long count); + +static inline long +strncpy_from_user(char *dst, const char __user *src, long count) +{ + if (access_ok(src, 1)) + return __strncpy_user(dst, src, count); + return -EFAULT; +} +#else +long strncpy_from_user(char *dst, const char __user *src, long count); +#endif + +/* + * Return the size of a string (including the ending 0!) + */ +extern long __strnlen_user(const char __user *str, long len); + +static inline long strnlen_user(const char __user *str, long len) +{ + if (!access_ok(str, 1)) + return 0; + return __strnlen_user(str, len); +} + +#endif /* _XTENSA_UACCESS_H */ |