298 lines
8 KiB
C
298 lines
8 KiB
C
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/*
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* Based on arch/arm/include/asm/uaccess.h
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*
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* Copyright (C) 2012 ARM Ltd.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#ifndef __ASM_UACCESS_H
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#define __ASM_UACCESS_H
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/*
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* User space memory access functions
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*/
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#include <linux/string.h>
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#include <linux/thread_info.h>
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#include <asm/ptrace.h>
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#include <asm/errno.h>
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#include <asm/memory.h>
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#include <asm/compiler.h>
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#define VERIFY_READ 0
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#define VERIFY_WRITE 1
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/*
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* The exception table consists of pairs of addresses: the first is the
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* address of an instruction that is allowed to fault, and the second is
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* the address at which the program should continue. No registers are
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* modified, so it is entirely up to the continuation code to figure out
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* what to do.
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*
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* All the routines below use bits of fixup code that are out of line
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* with the main instruction path. This means when everything is well,
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* we don't even have to jump over them. Further, they do not intrude
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* on our cache or tlb entries.
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*/
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struct exception_table_entry
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{
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unsigned long insn, fixup;
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};
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extern int fixup_exception(struct pt_regs *regs);
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#define KERNEL_DS (-1UL)
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#define get_ds() (KERNEL_DS)
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#define USER_DS TASK_SIZE_64
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#define get_fs() (current_thread_info()->addr_limit)
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static inline void set_fs(mm_segment_t fs)
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{
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current_thread_info()->addr_limit = fs;
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}
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#define segment_eq(a,b) ((a) == (b))
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/*
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* Return 1 if addr < current->addr_limit, 0 otherwise.
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*/
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#define __addr_ok(addr) \
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({ \
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unsigned long flag; \
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asm("cmp %1, %0; cset %0, lo" \
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: "=&r" (flag) \
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: "r" (addr), "0" (current_thread_info()->addr_limit) \
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: "cc"); \
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flag; \
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})
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/*
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* Test whether a block of memory is a valid user space address.
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* Returns 1 if the range is valid, 0 otherwise.
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*
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* This is equivalent to the following test:
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* (u65)addr + (u65)size < (u65)current->addr_limit
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*
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* This needs 65-bit arithmetic.
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*/
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#define __range_ok(addr, size) \
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({ \
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unsigned long flag, roksum; \
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__chk_user_ptr(addr); \
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asm("adds %1, %1, %3; ccmp %1, %4, #2, cc; cset %0, cc" \
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: "=&r" (flag), "=&r" (roksum) \
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: "1" (addr), "Ir" (size), \
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"r" (current_thread_info()->addr_limit) \
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: "cc"); \
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flag; \
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})
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#define access_ok(type, addr, size) __range_ok(addr, size)
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/*
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* The "__xxx" versions of the user access functions do not verify the address
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* space - it must have been done previously with a separate "access_ok()"
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* call.
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*
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* The "__xxx_error" versions set the third argument to -EFAULT if an error
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* occurs, and leave it unchanged on success.
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*/
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#define __get_user_asm(instr, reg, x, addr, err) \
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asm volatile( \
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"1: " instr " " reg "1, [%2]\n" \
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"2:\n" \
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" .section .fixup, \"ax\"\n" \
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" .align 2\n" \
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"3: mov %w0, %3\n" \
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" mov %1, #0\n" \
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" b 2b\n" \
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" .previous\n" \
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" .section __ex_table,\"a\"\n" \
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" .align 3\n" \
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" .quad 1b, 3b\n" \
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" .previous" \
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: "+r" (err), "=&r" (x) \
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: "r" (addr), "i" (-EFAULT))
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#define __get_user_err(x, ptr, err) \
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do { \
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unsigned long __gu_val; \
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__chk_user_ptr(ptr); \
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switch (sizeof(*(ptr))) { \
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case 1: \
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__get_user_asm("ldrb", "%w", __gu_val, (ptr), (err)); \
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break; \
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case 2: \
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__get_user_asm("ldrh", "%w", __gu_val, (ptr), (err)); \
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break; \
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case 4: \
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__get_user_asm("ldr", "%w", __gu_val, (ptr), (err)); \
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break; \
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case 8: \
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__get_user_asm("ldr", "%", __gu_val, (ptr), (err)); \
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break; \
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default: \
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BUILD_BUG(); \
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} \
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(x) = (__typeof__(*(ptr)))__gu_val; \
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} while (0)
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#define __get_user(x, ptr) \
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({ \
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int __gu_err = 0; \
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__get_user_err((x), (ptr), __gu_err); \
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__gu_err; \
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})
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#define __get_user_error(x, ptr, err) \
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({ \
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__get_user_err((x), (ptr), (err)); \
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(void)0; \
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})
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#define __get_user_unaligned __get_user
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#define get_user(x, ptr) \
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({ \
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might_sleep(); \
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access_ok(VERIFY_READ, (ptr), sizeof(*(ptr))) ? \
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__get_user((x), (ptr)) : \
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((x) = 0, -EFAULT); \
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})
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#define __put_user_asm(instr, reg, x, addr, err) \
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asm volatile( \
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"1: " instr " " reg "1, [%2]\n" \
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"2:\n" \
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" .section .fixup,\"ax\"\n" \
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" .align 2\n" \
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"3: mov %w0, %3\n" \
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" b 2b\n" \
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" .previous\n" \
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" .section __ex_table,\"a\"\n" \
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" .align 3\n" \
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" .quad 1b, 3b\n" \
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" .previous" \
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: "+r" (err) \
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: "r" (x), "r" (addr), "i" (-EFAULT))
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#define __put_user_err(x, ptr, err) \
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do { \
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__typeof__(*(ptr)) __pu_val = (x); \
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__chk_user_ptr(ptr); \
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switch (sizeof(*(ptr))) { \
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case 1: \
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__put_user_asm("strb", "%w", __pu_val, (ptr), (err)); \
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break; \
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case 2: \
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__put_user_asm("strh", "%w", __pu_val, (ptr), (err)); \
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break; \
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case 4: \
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__put_user_asm("str", "%w", __pu_val, (ptr), (err)); \
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break; \
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case 8: \
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__put_user_asm("str", "%", __pu_val, (ptr), (err)); \
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break; \
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default: \
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BUILD_BUG(); \
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} \
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} while (0)
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#define __put_user(x, ptr) \
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({ \
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int __pu_err = 0; \
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__put_user_err((x), (ptr), __pu_err); \
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__pu_err; \
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})
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#define __put_user_error(x, ptr, err) \
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({ \
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__put_user_err((x), (ptr), (err)); \
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(void)0; \
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})
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#define __put_user_unaligned __put_user
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#define put_user(x, ptr) \
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({ \
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might_sleep(); \
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access_ok(VERIFY_WRITE, (ptr), sizeof(*(ptr))) ? \
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__put_user((x), (ptr)) : \
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-EFAULT; \
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})
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extern unsigned long __must_check __copy_from_user(void *to, const void __user *from, unsigned long n);
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extern unsigned long __must_check __copy_to_user(void __user *to, const void *from, unsigned long n);
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extern unsigned long __must_check __copy_in_user(void __user *to, const void __user *from, unsigned long n);
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extern unsigned long __must_check __clear_user(void __user *addr, unsigned long n);
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extern unsigned long __must_check __strncpy_from_user(char *to, const char __user *from, unsigned long count);
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extern unsigned long __must_check __strnlen_user(const char __user *s, long n);
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static inline unsigned long __must_check copy_from_user(void *to, const void __user *from, unsigned long n)
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{
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if (access_ok(VERIFY_READ, from, n))
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n = __copy_from_user(to, from, n);
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else /* security hole - plug it */
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memset(to, 0, n);
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return n;
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}
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static inline unsigned long __must_check copy_to_user(void __user *to, const void *from, unsigned long n)
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{
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if (access_ok(VERIFY_WRITE, to, n))
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n = __copy_to_user(to, from, n);
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return n;
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}
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static inline unsigned long __must_check copy_in_user(void __user *to, const void __user *from, unsigned long n)
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{
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if (access_ok(VERIFY_READ, from, n) && access_ok(VERIFY_WRITE, to, n))
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n = __copy_in_user(to, from, n);
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return n;
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}
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#define __copy_to_user_inatomic __copy_to_user
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#define __copy_from_user_inatomic __copy_from_user
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static inline unsigned long __must_check clear_user(void __user *to, unsigned long n)
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{
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if (access_ok(VERIFY_WRITE, to, n))
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n = __clear_user(to, n);
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return n;
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}
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static inline long __must_check strncpy_from_user(char *dst, const char __user *src, long count)
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{
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long res = -EFAULT;
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if (access_ok(VERIFY_READ, src, 1))
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res = __strncpy_from_user(dst, src, count);
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return res;
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}
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#define strlen_user(s) strnlen_user(s, ~0UL >> 1)
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static inline long __must_check strnlen_user(const char __user *s, long n)
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{
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unsigned long res = 0;
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if (__addr_ok(s))
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res = __strnlen_user(s, n);
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return res;
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}
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#endif /* __ASM_UACCESS_H */
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