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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>
263 lines
7.8 KiB
C
263 lines
7.8 KiB
C
// SPDX-License-Identifier: GPL-2.0
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// Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd.
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#include <linux/uaccess.h>
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#include <linux/types.h>
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unsigned long raw_copy_from_user(void *to, const void *from,
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unsigned long n)
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{
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if (access_ok(from, n))
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__copy_user_zeroing(to, from, n);
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else
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memset(to, 0, n);
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return n;
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}
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EXPORT_SYMBOL(raw_copy_from_user);
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unsigned long raw_copy_to_user(void *to, const void *from,
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unsigned long n)
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{
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if (access_ok(to, n))
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__copy_user(to, from, n);
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return n;
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}
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EXPORT_SYMBOL(raw_copy_to_user);
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/*
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* copy a null terminated string from userspace.
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*/
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#define __do_strncpy_from_user(dst, src, count, res) \
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do { \
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int tmp; \
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long faultres; \
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asm volatile( \
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" cmpnei %3, 0 \n" \
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" bf 4f \n" \
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"1: cmpnei %1, 0 \n" \
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" bf 5f \n" \
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"2: ldb %4, (%3, 0) \n" \
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" stb %4, (%2, 0) \n" \
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" cmpnei %4, 0 \n" \
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" bf 3f \n" \
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" addi %3, 1 \n" \
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" addi %2, 1 \n" \
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" subi %1, 1 \n" \
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" br 1b \n" \
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"3: subu %0, %1 \n" \
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" br 5f \n" \
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"4: mov %0, %5 \n" \
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" br 5f \n" \
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".section __ex_table, \"a\" \n" \
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".align 2 \n" \
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".long 2b, 4b \n" \
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".previous \n" \
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"5: \n" \
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: "=r"(res), "=r"(count), "=r"(dst), \
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"=r"(src), "=r"(tmp), "=r"(faultres) \
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: "5"(-EFAULT), "0"(count), "1"(count), \
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"2"(dst), "3"(src) \
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: "memory", "cc"); \
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} while (0)
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/*
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* __strncpy_from_user: - Copy a NUL terminated string from userspace,
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* with less checking.
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* @dst: Destination address, in kernel space. This buffer must be at
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* least @count bytes long.
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* @src: Source address, in user space.
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* @count: Maximum number of bytes to copy, including the trailing NUL.
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*
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* Copies a NUL-terminated string from userspace to kernel space.
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* Caller must check the specified block with access_ok() before calling
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* this function.
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*
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* On success, returns the length of the string (not including the trailing
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* NUL).
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*
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* If access to userspace fails, returns -EFAULT (some data may have been
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* copied).
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*
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* If @count is smaller than the length of the string, copies @count bytes
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* and returns @count.
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*/
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long __strncpy_from_user(char *dst, const char *src, long count)
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{
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long res;
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__do_strncpy_from_user(dst, src, count, res);
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return res;
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}
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EXPORT_SYMBOL(__strncpy_from_user);
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/*
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* strncpy_from_user: - Copy a NUL terminated string from userspace.
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* @dst: Destination address, in kernel space. This buffer must be at
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* least @count bytes long.
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* @src: Source address, in user space.
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* @count: Maximum number of bytes to copy, including the trailing NUL.
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*
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* Copies a NUL-terminated string from userspace to kernel space.
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*
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* On success, returns the length of the string (not including the trailing
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* NUL).
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*
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* If access to userspace fails, returns -EFAULT (some data may have been
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* copied).
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*
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* If @count is smaller than the length of the string, copies @count bytes
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* and returns @count.
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*/
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long strncpy_from_user(char *dst, const char *src, long count)
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{
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long res = -EFAULT;
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if (access_ok(src, 1))
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__do_strncpy_from_user(dst, src, count, res);
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return res;
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}
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EXPORT_SYMBOL(strncpy_from_user);
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/*
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* strlen_user: - Get the size of a string in user space.
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* @str: The string to measure.
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* @n: The maximum valid length
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*
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* Get the size of a NUL-terminated string in user space.
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*
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* Returns the size of the string INCLUDING the terminating NUL.
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* On exception, returns 0.
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* If the string is too long, returns a value greater than @n.
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*/
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long strnlen_user(const char *s, long n)
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{
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unsigned long res, tmp;
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if (s == NULL)
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return 0;
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asm volatile(
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" cmpnei %1, 0 \n"
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" bf 3f \n"
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"1: cmpnei %0, 0 \n"
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" bf 3f \n"
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"2: ldb %3, (%1, 0) \n"
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" cmpnei %3, 0 \n"
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" bf 3f \n"
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" subi %0, 1 \n"
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" addi %1, 1 \n"
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" br 1b \n"
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"3: subu %2, %0 \n"
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" addi %2, 1 \n"
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" br 5f \n"
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"4: movi %0, 0 \n"
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" br 5f \n"
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".section __ex_table, \"a\" \n"
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".align 2 \n"
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".long 2b, 4b \n"
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".previous \n"
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"5: \n"
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: "=r"(n), "=r"(s), "=r"(res), "=r"(tmp)
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: "0"(n), "1"(s), "2"(n)
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: "memory", "cc");
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return res;
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}
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EXPORT_SYMBOL(strnlen_user);
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#define __do_clear_user(addr, size) \
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do { \
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int __d0, zvalue, tmp; \
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\
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asm volatile( \
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"0: cmpnei %1, 0 \n" \
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" bf 7f \n" \
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" mov %3, %1 \n" \
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" andi %3, 3 \n" \
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" cmpnei %3, 0 \n" \
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" bf 1f \n" \
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" br 5f \n" \
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"1: cmplti %0, 32 \n" /* 4W */ \
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" bt 3f \n" \
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"8: stw %2, (%1, 0) \n" \
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"10: stw %2, (%1, 4) \n" \
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"11: stw %2, (%1, 8) \n" \
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"12: stw %2, (%1, 12) \n" \
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"13: stw %2, (%1, 16) \n" \
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"14: stw %2, (%1, 20) \n" \
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"15: stw %2, (%1, 24) \n" \
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"16: stw %2, (%1, 28) \n" \
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" addi %1, 32 \n" \
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" subi %0, 32 \n" \
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" br 1b \n" \
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"3: cmplti %0, 4 \n" /* 1W */ \
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" bt 5f \n" \
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"4: stw %2, (%1, 0) \n" \
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" addi %1, 4 \n" \
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" subi %0, 4 \n" \
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" br 3b \n" \
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"5: cmpnei %0, 0 \n" /* 1B */ \
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"9: bf 7f \n" \
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"6: stb %2, (%1, 0) \n" \
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" addi %1, 1 \n" \
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" subi %0, 1 \n" \
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" br 5b \n" \
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".section __ex_table,\"a\" \n" \
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".align 2 \n" \
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".long 8b, 9b \n" \
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".long 10b, 9b \n" \
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".long 11b, 9b \n" \
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".long 12b, 9b \n" \
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".long 13b, 9b \n" \
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".long 14b, 9b \n" \
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".long 15b, 9b \n" \
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".long 16b, 9b \n" \
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".long 4b, 9b \n" \
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".long 6b, 9b \n" \
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".previous \n" \
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"7: \n" \
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: "=r"(size), "=r" (__d0), \
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"=r"(zvalue), "=r"(tmp) \
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: "0"(size), "1"(addr), "2"(0) \
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: "memory", "cc"); \
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} while (0)
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/*
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* clear_user: - Zero a block of memory in user space.
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* @to: Destination address, in user space.
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* @n: Number of bytes to zero.
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*
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* Zero a block of memory in user space.
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*
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* Returns number of bytes that could not be cleared.
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* On success, this will be zero.
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*/
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unsigned long
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clear_user(void __user *to, unsigned long n)
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{
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if (access_ok(to, n))
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__do_clear_user(to, n);
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return n;
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}
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EXPORT_SYMBOL(clear_user);
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/*
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* __clear_user: - Zero a block of memory in user space, with less checking.
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* @to: Destination address, in user space.
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* @n: Number of bytes to zero.
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*
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* Zero a block of memory in user space. Caller must check
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* the specified block with access_ok() before calling this function.
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*
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* Returns number of bytes that could not be cleared.
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* On success, this will be zero.
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*/
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unsigned long
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__clear_user(void __user *to, unsigned long n)
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{
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__do_clear_user(to, n);
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return n;
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}
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EXPORT_SYMBOL(__clear_user);
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