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