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96d4f267e4
Nobody has actually used the type (VERIFY_READ vs VERIFY_WRITE) argument
of the user address range verification function since we got rid of the
old racy i386-only code to walk page tables by hand.
It existed because the original 80386 would not honor the write protect
bit when in kernel mode, so you had to do COW by hand before doing any
user access. But we haven't supported that in a long time, and these
days the 'type' argument is a purely historical artifact.
A discussion about extending 'user_access_begin()' to do the range
checking resulted this patch, because there is no way we're going to
move the old VERIFY_xyz interface to that model. And it's best done at
the end of the merge window when I've done most of my merges, so let's
just get this done once and for all.
This patch was mostly done with a sed-script, with manual fix-ups for
the cases that weren't of the trivial 'access_ok(VERIFY_xyz' form.
There were a couple of notable cases:
- csky still had the old "verify_area()" name as an alias.
- the iter_iov code had magical hardcoded knowledge of the actual
values of VERIFY_{READ,WRITE} (not that they mattered, since nothing
really used it)
- microblaze used the type argument for a debug printout
but other than those oddities this should be a total no-op patch.
I tried to fix up all architectures, did fairly extensive grepping for
access_ok() uses, and the changes are trivial, but I may have missed
something. Any missed conversion should be trivially fixable, though.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
498 lines
14 KiB
C
498 lines
14 KiB
C
/*
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* Copyright (C) 2012 Regents of the University of California
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation, version 2.
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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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* This file was copied from include/asm-generic/uaccess.h
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*/
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#ifndef _ASM_RISCV_UACCESS_H
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#define _ASM_RISCV_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/errno.h>
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#include <linux/compiler.h>
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#include <linux/thread_info.h>
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#include <asm/byteorder.h>
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#include <asm/asm.h>
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#define __enable_user_access() \
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__asm__ __volatile__ ("csrs sstatus, %0" : : "r" (SR_SUM) : "memory")
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#define __disable_user_access() \
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__asm__ __volatile__ ("csrc sstatus, %0" : : "r" (SR_SUM) : "memory")
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/*
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* The fs value determines whether argument validity checking should be
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* performed or not. If get_fs() == USER_DS, checking is performed, with
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* get_fs() == KERNEL_DS, checking is bypassed.
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*
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* For historical reasons, these macros are grossly misnamed.
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*/
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#define KERNEL_DS (~0UL)
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#define USER_DS (TASK_SIZE)
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#define get_ds() (KERNEL_DS)
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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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#define user_addr_max() (get_fs())
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/**
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* access_ok: - Checks if a user space pointer is valid
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* @addr: User space pointer to start of block to check
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* @size: Size of block to check
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*
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* Context: User context only. This function may sleep.
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*
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* Checks if a pointer to a block of memory in user space is valid.
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*
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* Returns true (nonzero) if the memory block may be valid, false (zero)
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* if it is definitely invalid.
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*
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* Note that, depending on architecture, this function probably just
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* checks that the pointer is in the user space range - after calling
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* this function, memory access functions may still return -EFAULT.
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*/
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#define access_ok(addr, size) ({ \
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__chk_user_ptr(addr); \
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likely(__access_ok((unsigned long __force)(addr), (size))); \
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})
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/*
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* Ensure that the range [addr, addr+size) is within the process's
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* address space
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*/
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static inline int __access_ok(unsigned long addr, unsigned long size)
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{
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const mm_segment_t fs = get_fs();
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return (size <= fs) && (addr <= (fs - size));
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}
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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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unsigned long insn, fixup;
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};
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extern int fixup_exception(struct pt_regs *state);
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#if defined(__LITTLE_ENDIAN)
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#define __MSW 1
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#define __LSW 0
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#elif defined(__BIG_ENDIAN)
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#define __MSW 0
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#define __LSW 1
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#else
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#error "Unknown endianness"
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#endif
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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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#define __get_user_asm(insn, x, ptr, err) \
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do { \
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uintptr_t __tmp; \
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__typeof__(x) __x; \
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__enable_user_access(); \
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__asm__ __volatile__ ( \
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"1:\n" \
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" " insn " %1, %3\n" \
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"2:\n" \
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" .section .fixup,\"ax\"\n" \
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" .balign 4\n" \
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"3:\n" \
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" li %0, %4\n" \
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" li %1, 0\n" \
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" jump 2b, %2\n" \
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" .previous\n" \
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" .section __ex_table,\"a\"\n" \
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" .balign " RISCV_SZPTR "\n" \
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" " RISCV_PTR " 1b, 3b\n" \
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" .previous" \
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: "+r" (err), "=&r" (__x), "=r" (__tmp) \
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: "m" (*(ptr)), "i" (-EFAULT)); \
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__disable_user_access(); \
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(x) = __x; \
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} while (0)
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#ifdef CONFIG_64BIT
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#define __get_user_8(x, ptr, err) \
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__get_user_asm("ld", x, ptr, err)
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#else /* !CONFIG_64BIT */
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#define __get_user_8(x, ptr, err) \
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do { \
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u32 __user *__ptr = (u32 __user *)(ptr); \
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u32 __lo, __hi; \
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uintptr_t __tmp; \
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__enable_user_access(); \
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__asm__ __volatile__ ( \
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"1:\n" \
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" lw %1, %4\n" \
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"2:\n" \
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" lw %2, %5\n" \
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"3:\n" \
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" .section .fixup,\"ax\"\n" \
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" .balign 4\n" \
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"4:\n" \
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" li %0, %6\n" \
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" li %1, 0\n" \
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" li %2, 0\n" \
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" jump 3b, %3\n" \
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" .previous\n" \
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" .section __ex_table,\"a\"\n" \
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" .balign " RISCV_SZPTR "\n" \
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" " RISCV_PTR " 1b, 4b\n" \
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" " RISCV_PTR " 2b, 4b\n" \
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" .previous" \
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: "+r" (err), "=&r" (__lo), "=r" (__hi), \
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"=r" (__tmp) \
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: "m" (__ptr[__LSW]), "m" (__ptr[__MSW]), \
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"i" (-EFAULT)); \
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__disable_user_access(); \
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(x) = (__typeof__(x))((__typeof__((x)-(x)))( \
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(((u64)__hi << 32) | __lo))); \
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} while (0)
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#endif /* CONFIG_64BIT */
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/**
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* __get_user: - Get a simple variable from user space, with less checking.
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* @x: Variable to store result.
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* @ptr: Source address, in user space.
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*
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* Context: User context only. This function may sleep.
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*
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* This macro copies a single simple variable from user space to kernel
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* space. It supports simple types like char and int, but not larger
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* data types like structures or arrays.
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*
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* @ptr must have pointer-to-simple-variable type, and the result of
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* dereferencing @ptr must be assignable to @x without a cast.
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*
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* Caller must check the pointer with access_ok() before calling this
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* function.
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*
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* Returns zero on success, or -EFAULT on error.
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* On error, the variable @x is set to zero.
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*/
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#define __get_user(x, ptr) \
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({ \
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register long __gu_err = 0; \
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const __typeof__(*(ptr)) __user *__gu_ptr = (ptr); \
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__chk_user_ptr(__gu_ptr); \
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switch (sizeof(*__gu_ptr)) { \
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case 1: \
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__get_user_asm("lb", (x), __gu_ptr, __gu_err); \
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break; \
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case 2: \
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__get_user_asm("lh", (x), __gu_ptr, __gu_err); \
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break; \
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case 4: \
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__get_user_asm("lw", (x), __gu_ptr, __gu_err); \
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break; \
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case 8: \
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__get_user_8((x), __gu_ptr, __gu_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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__gu_err; \
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})
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/**
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* get_user: - Get a simple variable from user space.
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* @x: Variable to store result.
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* @ptr: Source address, in user space.
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*
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* Context: User context only. This function may sleep.
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*
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* This macro copies a single simple variable from user space to kernel
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* space. It supports simple types like char and int, but not larger
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* data types like structures or arrays.
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*
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* @ptr must have pointer-to-simple-variable type, and the result of
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* dereferencing @ptr must be assignable to @x without a cast.
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*
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* Returns zero on success, or -EFAULT on error.
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* On error, the variable @x is set to zero.
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*/
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#define get_user(x, ptr) \
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({ \
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const __typeof__(*(ptr)) __user *__p = (ptr); \
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might_fault(); \
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access_ok(__p, sizeof(*__p)) ? \
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__get_user((x), __p) : \
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((x) = 0, -EFAULT); \
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})
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#define __put_user_asm(insn, x, ptr, err) \
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do { \
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uintptr_t __tmp; \
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__typeof__(*(ptr)) __x = x; \
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__enable_user_access(); \
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__asm__ __volatile__ ( \
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"1:\n" \
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" " insn " %z3, %2\n" \
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"2:\n" \
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" .section .fixup,\"ax\"\n" \
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" .balign 4\n" \
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"3:\n" \
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" li %0, %4\n" \
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" jump 2b, %1\n" \
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" .previous\n" \
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" .section __ex_table,\"a\"\n" \
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" .balign " RISCV_SZPTR "\n" \
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" " RISCV_PTR " 1b, 3b\n" \
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" .previous" \
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: "+r" (err), "=r" (__tmp), "=m" (*(ptr)) \
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: "rJ" (__x), "i" (-EFAULT)); \
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__disable_user_access(); \
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} while (0)
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#ifdef CONFIG_64BIT
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#define __put_user_8(x, ptr, err) \
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__put_user_asm("sd", x, ptr, err)
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#else /* !CONFIG_64BIT */
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#define __put_user_8(x, ptr, err) \
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do { \
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u32 __user *__ptr = (u32 __user *)(ptr); \
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u64 __x = (__typeof__((x)-(x)))(x); \
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uintptr_t __tmp; \
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__enable_user_access(); \
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__asm__ __volatile__ ( \
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"1:\n" \
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" sw %z4, %2\n" \
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"2:\n" \
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" sw %z5, %3\n" \
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"3:\n" \
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" .section .fixup,\"ax\"\n" \
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" .balign 4\n" \
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"4:\n" \
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" li %0, %6\n" \
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" jump 2b, %1\n" \
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" .previous\n" \
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" .section __ex_table,\"a\"\n" \
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" .balign " RISCV_SZPTR "\n" \
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" " RISCV_PTR " 1b, 4b\n" \
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" " RISCV_PTR " 2b, 4b\n" \
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" .previous" \
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: "+r" (err), "=r" (__tmp), \
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"=m" (__ptr[__LSW]), \
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"=m" (__ptr[__MSW]) \
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: "rJ" (__x), "rJ" (__x >> 32), "i" (-EFAULT)); \
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__disable_user_access(); \
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} while (0)
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#endif /* CONFIG_64BIT */
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/**
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* __put_user: - Write a simple value into user space, with less checking.
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* @x: Value to copy to user space.
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* @ptr: Destination address, in user space.
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*
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* Context: User context only. This function may sleep.
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*
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* This macro copies a single simple value from kernel space to user
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* space. It supports simple types like char and int, but not larger
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* data types like structures or arrays.
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*
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* @ptr must have pointer-to-simple-variable type, and @x must be assignable
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* to the result of dereferencing @ptr.
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*
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* Caller must check the pointer with access_ok() before calling this
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* function.
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*
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* Returns zero on success, or -EFAULT on error.
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*/
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#define __put_user(x, ptr) \
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({ \
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register long __pu_err = 0; \
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__typeof__(*(ptr)) __user *__gu_ptr = (ptr); \
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__chk_user_ptr(__gu_ptr); \
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switch (sizeof(*__gu_ptr)) { \
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case 1: \
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__put_user_asm("sb", (x), __gu_ptr, __pu_err); \
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break; \
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case 2: \
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__put_user_asm("sh", (x), __gu_ptr, __pu_err); \
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break; \
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case 4: \
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__put_user_asm("sw", (x), __gu_ptr, __pu_err); \
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break; \
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case 8: \
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__put_user_8((x), __gu_ptr, __pu_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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__pu_err; \
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})
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/**
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* put_user: - Write a simple value into user space.
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* @x: Value to copy to user space.
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* @ptr: Destination address, in user space.
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*
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* Context: User context only. This function may sleep.
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*
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* This macro copies a single simple value from kernel space to user
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* space. It supports simple types like char and int, but not larger
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* data types like structures or arrays.
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*
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* @ptr must have pointer-to-simple-variable type, and @x must be assignable
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* to the result of dereferencing @ptr.
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*
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* Returns zero on success, or -EFAULT on error.
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*/
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#define put_user(x, ptr) \
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({ \
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__typeof__(*(ptr)) __user *__p = (ptr); \
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might_fault(); \
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access_ok(__p, sizeof(*__p)) ? \
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__put_user((x), __p) : \
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-EFAULT; \
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})
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extern unsigned long __must_check __asm_copy_to_user(void __user *to,
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const void *from, unsigned long n);
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extern unsigned long __must_check __asm_copy_from_user(void *to,
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const void __user *from, unsigned long 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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return __asm_copy_from_user(to, 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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return __asm_copy_to_user(to, from, n);
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}
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extern long strncpy_from_user(char *dest, const char __user *src, long count);
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extern long __must_check strlen_user(const char __user *str);
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extern long __must_check strnlen_user(const char __user *str, long n);
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extern
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unsigned long __must_check __clear_user(void __user *addr, unsigned long n);
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static inline
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unsigned long __must_check clear_user(void __user *to, unsigned long n)
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{
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might_fault();
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return access_ok(to, n) ?
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__clear_user(to, n) : n;
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}
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/*
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* Atomic compare-and-exchange, but with a fixup for userspace faults. Faults
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* will set "err" to -EFAULT, while successful accesses return the previous
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* value.
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*/
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#define __cmpxchg_user(ptr, old, new, err, size, lrb, scb) \
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({ \
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__typeof__(ptr) __ptr = (ptr); \
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__typeof__(*(ptr)) __old = (old); \
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__typeof__(*(ptr)) __new = (new); \
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__typeof__(*(ptr)) __ret; \
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__typeof__(err) __err = 0; \
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register unsigned int __rc; \
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__enable_user_access(); \
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switch (size) { \
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case 4: \
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__asm__ __volatile__ ( \
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"0:\n" \
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" lr.w" #scb " %[ret], %[ptr]\n" \
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" bne %[ret], %z[old], 1f\n" \
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" sc.w" #lrb " %[rc], %z[new], %[ptr]\n" \
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" bnez %[rc], 0b\n" \
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"1:\n" \
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".section .fixup,\"ax\"\n" \
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".balign 4\n" \
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"2:\n" \
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" li %[err], %[efault]\n" \
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" jump 1b, %[rc]\n" \
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".previous\n" \
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".section __ex_table,\"a\"\n" \
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".balign " RISCV_SZPTR "\n" \
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" " RISCV_PTR " 1b, 2b\n" \
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".previous\n" \
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: [ret] "=&r" (__ret), \
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[rc] "=&r" (__rc), \
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[ptr] "+A" (*__ptr), \
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[err] "=&r" (__err) \
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|
: [old] "rJ" (__old), \
|
|
[new] "rJ" (__new), \
|
|
[efault] "i" (-EFAULT)); \
|
|
break; \
|
|
case 8: \
|
|
__asm__ __volatile__ ( \
|
|
"0:\n" \
|
|
" lr.d" #scb " %[ret], %[ptr]\n" \
|
|
" bne %[ret], %z[old], 1f\n" \
|
|
" sc.d" #lrb " %[rc], %z[new], %[ptr]\n" \
|
|
" bnez %[rc], 0b\n" \
|
|
"1:\n" \
|
|
".section .fixup,\"ax\"\n" \
|
|
".balign 4\n" \
|
|
"2:\n" \
|
|
" li %[err], %[efault]\n" \
|
|
" jump 1b, %[rc]\n" \
|
|
".previous\n" \
|
|
".section __ex_table,\"a\"\n" \
|
|
".balign " RISCV_SZPTR "\n" \
|
|
" " RISCV_PTR " 1b, 2b\n" \
|
|
".previous\n" \
|
|
: [ret] "=&r" (__ret), \
|
|
[rc] "=&r" (__rc), \
|
|
[ptr] "+A" (*__ptr), \
|
|
[err] "=&r" (__err) \
|
|
: [old] "rJ" (__old), \
|
|
[new] "rJ" (__new), \
|
|
[efault] "i" (-EFAULT)); \
|
|
break; \
|
|
default: \
|
|
BUILD_BUG(); \
|
|
} \
|
|
__disable_user_access(); \
|
|
(err) = __err; \
|
|
__ret; \
|
|
})
|
|
|
|
#endif /* _ASM_RISCV_UACCESS_H */
|