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linux/arch/x86/lib/usercopy_32.c
Linus Torvalds 92ae03f2ef x86: merge 32/64-bit versions of 'strncpy_from_user()' and speed it up 
This merges the 32- and 64-bit versions of the x86 strncpy_from_user()
by just rewriting it in C rather than the ancient inline asm versions
that used lodsb/stosb and had been duplicated for (trivial) differences
between the 32-bit and 64-bit versions.

While doing that, it also speeds them up by doing the accesses a word at
a time.  Finally, the new routines also properly handle the case of
hitting the end of the address space, which we have never done correctly
before (fs/namei.c has a hack around it for that reason).

Despite all these improvements, it actually removes more lines than it
adds, due to the de-duplication.  Also, we no longer export (or define)
the legacy __strncpy_from_user() function (that was defined to not do
the user permission checks), since it's not actually used anywhere, and
the user address space checks are built in to the new code.

Other architecture maintainers have been notified that the old hack in
fs/namei.c will be going away in the 3.5 merge window, in case they
copied the x86 approach of being a bit cavalier about the end of the
address space.

Cc: linux-arch@vger.kernel.org
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Peter Anvin" <hpa@zytor.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-04-11 09:41:28 -07:00

805 lines
23 KiB
C
Raw Blame History

/*
* User address space access functions.
* The non inlined parts of asm-i386/uaccess.h are here.
*
* Copyright 1997 Andi Kleen <ak@muc.de>
* Copyright 1997 Linus Torvalds
*/
#include <linux/mm.h>
#include <linux/highmem.h>
#include <linux/blkdev.h>
#include <linux/module.h>
#include <linux/backing-dev.h>
#include <linux/interrupt.h>
#include <asm/uaccess.h>
#include <asm/mmx.h>
#ifdef CONFIG_X86_INTEL_USERCOPY
/*
* Alignment at which movsl is preferred for bulk memory copies.
*/
struct movsl_mask movsl_mask __read_mostly;
#endif
static inline int __movsl_is_ok(unsigned long a1, unsigned long a2, unsigned long n)
{
#ifdef CONFIG_X86_INTEL_USERCOPY
if (n >= 64 && ((a1 ^ a2) & movsl_mask.mask))
return 0;
#endif
return 1;
}
#define movsl_is_ok(a1, a2, n) \
__movsl_is_ok((unsigned long)(a1), (unsigned long)(a2), (n))
/*
* Zero Userspace
*/
#define __do_clear_user(addr,size) \
do { \
int __d0; \
might_fault(); \
__asm__ __volatile__( \
"0: rep; stosl\n" \
" movl %2,%0\n" \
"1: rep; stosb\n" \
"2:\n" \
".section .fixup,\"ax\"\n" \
"3: lea 0(%2,%0,4),%0\n" \
" jmp 2b\n" \
".previous\n" \
_ASM_EXTABLE(0b,3b) \
_ASM_EXTABLE(1b,2b) \
: "=&c"(size), "=&D" (__d0) \
: "r"(size & 3), "0"(size / 4), "1"(addr), "a"(0)); \
} while (0)
/**
* clear_user: - Zero a block of memory in user space.
* @to: Destination address, in user space.
* @n: Number of bytes to zero.
*
* Zero a block of memory in user space.
*
* Returns number of bytes that could not be cleared.
* On success, this will be zero.
*/
unsigned long
clear_user(void __user *to, unsigned long n)
{
might_fault();
if (access_ok(VERIFY_WRITE, to, n))
__do_clear_user(to, n);
return n;
}
EXPORT_SYMBOL(clear_user);
/**
* __clear_user: - Zero a block of memory in user space, with less checking.
* @to: Destination address, in user space.
* @n: Number of bytes to zero.
*
* Zero a block of memory in user space. Caller must check
* the specified block with access_ok() before calling this function.
*
* Returns number of bytes that could not be cleared.
* On success, this will be zero.
*/
unsigned long
__clear_user(void __user *to, unsigned long n)
{
__do_clear_user(to, n);
return n;
}
EXPORT_SYMBOL(__clear_user);
/**
* strnlen_user: - Get the size of a string in user space.
* @s: The string to measure.
* @n: The maximum valid length
*
* Get the size of a NUL-terminated string in user space.
*
* Returns the size of the string INCLUDING the terminating NUL.
* On exception, returns 0.
* If the string is too long, returns a value greater than @n.
*/
long strnlen_user(const char __user *s, long n)
{
unsigned long mask = -__addr_ok(s);
unsigned long res, tmp;
might_fault();
__asm__ __volatile__(
" testl %0, %0\n"
" jz 3f\n"
" andl %0,%%ecx\n"
"0: repne; scasb\n"
" setne %%al\n"
" subl %%ecx,%0\n"
" addl %0,%%eax\n"
"1:\n"
".section .fixup,\"ax\"\n"
"2: xorl %%eax,%%eax\n"
" jmp 1b\n"
"3: movb $1,%%al\n"
" jmp 1b\n"
".previous\n"
".section __ex_table,\"a\"\n"
" .align 4\n"
" .long 0b,2b\n"
".previous"
:"=&r" (n), "=&D" (s), "=&a" (res), "=&c" (tmp)
:"0" (n), "1" (s), "2" (0), "3" (mask)
:"cc");
return res & mask;
}
EXPORT_SYMBOL(strnlen_user);
#ifdef CONFIG_X86_INTEL_USERCOPY
static unsigned long
__copy_user_intel(void __user *to, const void *from, unsigned long size)
{
int d0, d1;
__asm__ __volatile__(
" .align 2,0x90\n"
"1: movl 32(%4), %%eax\n"
" cmpl $67, %0\n"
" jbe 3f\n"
"2: movl 64(%4), %%eax\n"
" .align 2,0x90\n"
"3: movl 0(%4), %%eax\n"
"4: movl 4(%4), %%edx\n"
"5: movl %%eax, 0(%3)\n"
"6: movl %%edx, 4(%3)\n"
"7: movl 8(%4), %%eax\n"
"8: movl 12(%4),%%edx\n"
"9: movl %%eax, 8(%3)\n"
"10: movl %%edx, 12(%3)\n"
"11: movl 16(%4), %%eax\n"
"12: movl 20(%4), %%edx\n"
"13: movl %%eax, 16(%3)\n"
"14: movl %%edx, 20(%3)\n"
"15: movl 24(%4), %%eax\n"
"16: movl 28(%4), %%edx\n"
"17: movl %%eax, 24(%3)\n"
"18: movl %%edx, 28(%3)\n"
"19: movl 32(%4), %%eax\n"
"20: movl 36(%4), %%edx\n"
"21: movl %%eax, 32(%3)\n"
"22: movl %%edx, 36(%3)\n"
"23: movl 40(%4), %%eax\n"
"24: movl 44(%4), %%edx\n"
"25: movl %%eax, 40(%3)\n"
"26: movl %%edx, 44(%3)\n"
"27: movl 48(%4), %%eax\n"
"28: movl 52(%4), %%edx\n"
"29: movl %%eax, 48(%3)\n"
"30: movl %%edx, 52(%3)\n"
"31: movl 56(%4), %%eax\n"
"32: movl 60(%4), %%edx\n"
"33: movl %%eax, 56(%3)\n"
"34: movl %%edx, 60(%3)\n"
" addl $-64, %0\n"
" addl $64, %4\n"
" addl $64, %3\n"
" cmpl $63, %0\n"
" ja 1b\n"
"35: movl %0, %%eax\n"
" shrl $2, %0\n"
" andl $3, %%eax\n"
" cld\n"
"99: rep; movsl\n"
"36: movl %%eax, %0\n"
"37: rep; movsb\n"
"100:\n"
".section .fixup,\"ax\"\n"
"101: lea 0(%%eax,%0,4),%0\n"
" jmp 100b\n"
".previous\n"
".section __ex_table,\"a\"\n"
" .align 4\n"
" .long 1b,100b\n"
" .long 2b,100b\n"
" .long 3b,100b\n"
" .long 4b,100b\n"
" .long 5b,100b\n"
" .long 6b,100b\n"
" .long 7b,100b\n"
" .long 8b,100b\n"
" .long 9b,100b\n"
" .long 10b,100b\n"
" .long 11b,100b\n"
" .long 12b,100b\n"
" .long 13b,100b\n"
" .long 14b,100b\n"
" .long 15b,100b\n"
" .long 16b,100b\n"
" .long 17b,100b\n"
" .long 18b,100b\n"
" .long 19b,100b\n"
" .long 20b,100b\n"
" .long 21b,100b\n"
" .long 22b,100b\n"
" .long 23b,100b\n"
" .long 24b,100b\n"
" .long 25b,100b\n"
" .long 26b,100b\n"
" .long 27b,100b\n"
" .long 28b,100b\n"
" .long 29b,100b\n"
" .long 30b,100b\n"
" .long 31b,100b\n"
" .long 32b,100b\n"
" .long 33b,100b\n"
" .long 34b,100b\n"
" .long 35b,100b\n"
" .long 36b,100b\n"
" .long 37b,100b\n"
" .long 99b,101b\n"
".previous"
: "=&c"(size), "=&D" (d0), "=&S" (d1)
: "1"(to), "2"(from), "0"(size)
: "eax", "edx", "memory");
return size;
}
static unsigned long
__copy_user_zeroing_intel(void *to, const void __user *from, unsigned long size)
{
int d0, d1;
__asm__ __volatile__(
" .align 2,0x90\n"
"0: movl 32(%4), %%eax\n"
" cmpl $67, %0\n"
" jbe 2f\n"
"1: movl 64(%4), %%eax\n"
" .align 2,0x90\n"
"2: movl 0(%4), %%eax\n"
"21: movl 4(%4), %%edx\n"
" movl %%eax, 0(%3)\n"
" movl %%edx, 4(%3)\n"
"3: movl 8(%4), %%eax\n"
"31: movl 12(%4),%%edx\n"
" movl %%eax, 8(%3)\n"
" movl %%edx, 12(%3)\n"
"4: movl 16(%4), %%eax\n"
"41: movl 20(%4), %%edx\n"
" movl %%eax, 16(%3)\n"
" movl %%edx, 20(%3)\n"
"10: movl 24(%4), %%eax\n"
"51: movl 28(%4), %%edx\n"
" movl %%eax, 24(%3)\n"
" movl %%edx, 28(%3)\n"
"11: movl 32(%4), %%eax\n"
"61: movl 36(%4), %%edx\n"
" movl %%eax, 32(%3)\n"
" movl %%edx, 36(%3)\n"
"12: movl 40(%4), %%eax\n"
"71: movl 44(%4), %%edx\n"
" movl %%eax, 40(%3)\n"
" movl %%edx, 44(%3)\n"
"13: movl 48(%4), %%eax\n"
"81: movl 52(%4), %%edx\n"
" movl %%eax, 48(%3)\n"
" movl %%edx, 52(%3)\n"
"14: movl 56(%4), %%eax\n"
"91: movl 60(%4), %%edx\n"
" movl %%eax, 56(%3)\n"
" movl %%edx, 60(%3)\n"
" addl $-64, %0\n"
" addl $64, %4\n"
" addl $64, %3\n"
" cmpl $63, %0\n"
" ja 0b\n"
"5: movl %0, %%eax\n"
" shrl $2, %0\n"
" andl $3, %%eax\n"
" cld\n"
"6: rep; movsl\n"
" movl %%eax,%0\n"
"7: rep; movsb\n"
"8:\n"
".section .fixup,\"ax\"\n"
"9: lea 0(%%eax,%0,4),%0\n"
"16: pushl %0\n"
" pushl %%eax\n"
" xorl %%eax,%%eax\n"
" rep; stosb\n"
" popl %%eax\n"
" popl %0\n"
" jmp 8b\n"
".previous\n"
".section __ex_table,\"a\"\n"
" .align 4\n"
" .long 0b,16b\n"
" .long 1b,16b\n"
" .long 2b,16b\n"
" .long 21b,16b\n"
" .long 3b,16b\n"
" .long 31b,16b\n"
" .long 4b,16b\n"
" .long 41b,16b\n"
" .long 10b,16b\n"
" .long 51b,16b\n"
" .long 11b,16b\n"
" .long 61b,16b\n"
" .long 12b,16b\n"
" .long 71b,16b\n"
" .long 13b,16b\n"
" .long 81b,16b\n"
" .long 14b,16b\n"
" .long 91b,16b\n"
" .long 6b,9b\n"
" .long 7b,16b\n"
".previous"
: "=&c"(size), "=&D" (d0), "=&S" (d1)
: "1"(to), "2"(from), "0"(size)
: "eax", "edx", "memory");
return size;
}
/*
* Non Temporal Hint version of __copy_user_zeroing_intel. It is cache aware.
* hyoshiok@miraclelinux.com
*/
static unsigned long __copy_user_zeroing_intel_nocache(void *to,
const void __user *from, unsigned long size)
{
int d0, d1;
__asm__ __volatile__(
" .align 2,0x90\n"
"0: movl 32(%4), %%eax\n"
" cmpl $67, %0\n"
" jbe 2f\n"
"1: movl 64(%4), %%eax\n"
" .align 2,0x90\n"
"2: movl 0(%4), %%eax\n"
"21: movl 4(%4), %%edx\n"
" movnti %%eax, 0(%3)\n"
" movnti %%edx, 4(%3)\n"
"3: movl 8(%4), %%eax\n"
"31: movl 12(%4),%%edx\n"
" movnti %%eax, 8(%3)\n"
" movnti %%edx, 12(%3)\n"
"4: movl 16(%4), %%eax\n"
"41: movl 20(%4), %%edx\n"
" movnti %%eax, 16(%3)\n"
" movnti %%edx, 20(%3)\n"
"10: movl 24(%4), %%eax\n"
"51: movl 28(%4), %%edx\n"
" movnti %%eax, 24(%3)\n"
" movnti %%edx, 28(%3)\n"
"11: movl 32(%4), %%eax\n"
"61: movl 36(%4), %%edx\n"
" movnti %%eax, 32(%3)\n"
" movnti %%edx, 36(%3)\n"
"12: movl 40(%4), %%eax\n"
"71: movl 44(%4), %%edx\n"
" movnti %%eax, 40(%3)\n"
" movnti %%edx, 44(%3)\n"
"13: movl 48(%4), %%eax\n"
"81: movl 52(%4), %%edx\n"
" movnti %%eax, 48(%3)\n"
" movnti %%edx, 52(%3)\n"
"14: movl 56(%4), %%eax\n"
"91: movl 60(%4), %%edx\n"
" movnti %%eax, 56(%3)\n"
" movnti %%edx, 60(%3)\n"
" addl $-64, %0\n"
" addl $64, %4\n"
" addl $64, %3\n"
" cmpl $63, %0\n"
" ja 0b\n"
" sfence \n"
"5: movl %0, %%eax\n"
" shrl $2, %0\n"
" andl $3, %%eax\n"
" cld\n"
"6: rep; movsl\n"
" movl %%eax,%0\n"
"7: rep; movsb\n"
"8:\n"
".section .fixup,\"ax\"\n"
"9: lea 0(%%eax,%0,4),%0\n"
"16: pushl %0\n"
" pushl %%eax\n"
" xorl %%eax,%%eax\n"
" rep; stosb\n"
" popl %%eax\n"
" popl %0\n"
" jmp 8b\n"
".previous\n"
".section __ex_table,\"a\"\n"
" .align 4\n"
" .long 0b,16b\n"
" .long 1b,16b\n"
" .long 2b,16b\n"
" .long 21b,16b\n"
" .long 3b,16b\n"
" .long 31b,16b\n"
" .long 4b,16b\n"
" .long 41b,16b\n"
" .long 10b,16b\n"
" .long 51b,16b\n"
" .long 11b,16b\n"
" .long 61b,16b\n"
" .long 12b,16b\n"
" .long 71b,16b\n"
" .long 13b,16b\n"
" .long 81b,16b\n"
" .long 14b,16b\n"
" .long 91b,16b\n"
" .long 6b,9b\n"
" .long 7b,16b\n"
".previous"
: "=&c"(size), "=&D" (d0), "=&S" (d1)
: "1"(to), "2"(from), "0"(size)
: "eax", "edx", "memory");
return size;
}
static unsigned long __copy_user_intel_nocache(void *to,
const void __user *from, unsigned long size)
{
int d0, d1;
__asm__ __volatile__(
" .align 2,0x90\n"
"0: movl 32(%4), %%eax\n"
" cmpl $67, %0\n"
" jbe 2f\n"
"1: movl 64(%4), %%eax\n"
" .align 2,0x90\n"
"2: movl 0(%4), %%eax\n"
"21: movl 4(%4), %%edx\n"
" movnti %%eax, 0(%3)\n"
" movnti %%edx, 4(%3)\n"
"3: movl 8(%4), %%eax\n"
"31: movl 12(%4),%%edx\n"
" movnti %%eax, 8(%3)\n"
" movnti %%edx, 12(%3)\n"
"4: movl 16(%4), %%eax\n"
"41: movl 20(%4), %%edx\n"
" movnti %%eax, 16(%3)\n"
" movnti %%edx, 20(%3)\n"
"10: movl 24(%4), %%eax\n"
"51: movl 28(%4), %%edx\n"
" movnti %%eax, 24(%3)\n"
" movnti %%edx, 28(%3)\n"
"11: movl 32(%4), %%eax\n"
"61: movl 36(%4), %%edx\n"
" movnti %%eax, 32(%3)\n"
" movnti %%edx, 36(%3)\n"
"12: movl 40(%4), %%eax\n"
"71: movl 44(%4), %%edx\n"
" movnti %%eax, 40(%3)\n"
" movnti %%edx, 44(%3)\n"
"13: movl 48(%4), %%eax\n"
"81: movl 52(%4), %%edx\n"
" movnti %%eax, 48(%3)\n"
" movnti %%edx, 52(%3)\n"
"14: movl 56(%4), %%eax\n"
"91: movl 60(%4), %%edx\n"
" movnti %%eax, 56(%3)\n"
" movnti %%edx, 60(%3)\n"
" addl $-64, %0\n"
" addl $64, %4\n"
" addl $64, %3\n"
" cmpl $63, %0\n"
" ja 0b\n"
" sfence \n"
"5: movl %0, %%eax\n"
" shrl $2, %0\n"
" andl $3, %%eax\n"
" cld\n"
"6: rep; movsl\n"
" movl %%eax,%0\n"
"7: rep; movsb\n"
"8:\n"
".section .fixup,\"ax\"\n"
"9: lea 0(%%eax,%0,4),%0\n"
"16: jmp 8b\n"
".previous\n"
".section __ex_table,\"a\"\n"
" .align 4\n"
" .long 0b,16b\n"
" .long 1b,16b\n"
" .long 2b,16b\n"
" .long 21b,16b\n"
" .long 3b,16b\n"
" .long 31b,16b\n"
" .long 4b,16b\n"
" .long 41b,16b\n"
" .long 10b,16b\n"
" .long 51b,16b\n"
" .long 11b,16b\n"
" .long 61b,16b\n"
" .long 12b,16b\n"
" .long 71b,16b\n"
" .long 13b,16b\n"
" .long 81b,16b\n"
" .long 14b,16b\n"
" .long 91b,16b\n"
" .long 6b,9b\n"
" .long 7b,16b\n"
".previous"
: "=&c"(size), "=&D" (d0), "=&S" (d1)
: "1"(to), "2"(from), "0"(size)
: "eax", "edx", "memory");
return size;
}
#else
/*
* Leave these declared but undefined. They should not be any references to
* them
*/
unsigned long __copy_user_zeroing_intel(void *to, const void __user *from,
unsigned long size);
unsigned long __copy_user_intel(void __user *to, const void *from,
unsigned long size);
unsigned long __copy_user_zeroing_intel_nocache(void *to,
const void __user *from, unsigned long size);
#endif /* CONFIG_X86_INTEL_USERCOPY */
/* Generic arbitrary sized copy. */
#define __copy_user(to, from, size) \
do { \
int __d0, __d1, __d2; \
__asm__ __volatile__( \
" cmp $7,%0\n" \
" jbe 1f\n" \
" movl %1,%0\n" \
" negl %0\n" \
" andl $7,%0\n" \
" subl %0,%3\n" \
"4: rep; movsb\n" \
" movl %3,%0\n" \
" shrl $2,%0\n" \
" andl $3,%3\n" \
" .align 2,0x90\n" \
"0: rep; movsl\n" \
" movl %3,%0\n" \
"1: rep; movsb\n" \
"2:\n" \
".section .fixup,\"ax\"\n" \
"5: addl %3,%0\n" \
" jmp 2b\n" \
"3: lea 0(%3,%0,4),%0\n" \
" jmp 2b\n" \
".previous\n" \
".section __ex_table,\"a\"\n" \
" .align 4\n" \
" .long 4b,5b\n" \
" .long 0b,3b\n" \
" .long 1b,2b\n" \
".previous" \
: "=&c"(size), "=&D" (__d0), "=&S" (__d1), "=r"(__d2) \
: "3"(size), "0"(size), "1"(to), "2"(from) \
: "memory"); \
} while (0)
#define __copy_user_zeroing(to, from, size) \
do { \
int __d0, __d1, __d2; \
__asm__ __volatile__( \
" cmp $7,%0\n" \
" jbe 1f\n" \
" movl %1,%0\n" \
" negl %0\n" \
" andl $7,%0\n" \
" subl %0,%3\n" \
"4: rep; movsb\n" \
" movl %3,%0\n" \
" shrl $2,%0\n" \
" andl $3,%3\n" \
" .align 2,0x90\n" \
"0: rep; movsl\n" \
" movl %3,%0\n" \
"1: rep; movsb\n" \
"2:\n" \
".section .fixup,\"ax\"\n" \
"5: addl %3,%0\n" \
" jmp 6f\n" \
"3: lea 0(%3,%0,4),%0\n" \
"6: pushl %0\n" \
" pushl %%eax\n" \
" xorl %%eax,%%eax\n" \
" rep; stosb\n" \
" popl %%eax\n" \
" popl %0\n" \
" jmp 2b\n" \
".previous\n" \
".section __ex_table,\"a\"\n" \
" .align 4\n" \
" .long 4b,5b\n" \
" .long 0b,3b\n" \
" .long 1b,6b\n" \
".previous" \
: "=&c"(size), "=&D" (__d0), "=&S" (__d1), "=r"(__d2) \
: "3"(size), "0"(size), "1"(to), "2"(from) \
: "memory"); \
} while (0)
unsigned long __copy_to_user_ll(void __user *to, const void *from,
unsigned long n)
{
#ifndef CONFIG_X86_WP_WORKS_OK
if (unlikely(boot_cpu_data.wp_works_ok == 0) &&
((unsigned long)to) < TASK_SIZE) {
/*
* When we are in an atomic section (see
* mm/filemap.c:file_read_actor), return the full
* length to take the slow path.
*/
if (in_atomic())
return n;
/*
* CPU does not honor the WP bit when writing
* from supervisory mode, and due to preemption or SMP,
* the page tables can change at any time.
* Do it manually. Manfred <manfred@colorfullife.com>
*/
while (n) {
unsigned long offset = ((unsigned long)to)%PAGE_SIZE;
unsigned long len = PAGE_SIZE - offset;
int retval;
struct page *pg;
void *maddr;
if (len > n)
len = n;
survive:
down_read(&current->mm->mmap_sem);
retval = get_user_pages(current, current->mm,
(unsigned long)to, 1, 1, 0, &pg, NULL);
if (retval == -ENOMEM && is_global_init(current)) {
up_read(&current->mm->mmap_sem);
congestion_wait(BLK_RW_ASYNC, HZ/50);
goto survive;
}
if (retval != 1) {
up_read(&current->mm->mmap_sem);
break;
}
maddr = kmap_atomic(pg);
memcpy(maddr + offset, from, len);
kunmap_atomic(maddr);
set_page_dirty_lock(pg);
put_page(pg);
up_read(&current->mm->mmap_sem);
from += len;
to += len;
n -= len;
}
return n;
}
#endif
if (movsl_is_ok(to, from, n))
__copy_user(to, from, n);
else
n = __copy_user_intel(to, from, n);
return n;
}
EXPORT_SYMBOL(__copy_to_user_ll);
unsigned long __copy_from_user_ll(void *to, const void __user *from,
unsigned long n)
{
if (movsl_is_ok(to, from, n))
__copy_user_zeroing(to, from, n);
else
n = __copy_user_zeroing_intel(to, from, n);
return n;
}
EXPORT_SYMBOL(__copy_from_user_ll);
unsigned long __copy_from_user_ll_nozero(void *to, const void __user *from,
unsigned long n)
{
if (movsl_is_ok(to, from, n))
__copy_user(to, from, n);
else
n = __copy_user_intel((void __user *)to,
(const void *)from, n);
return n;
}
EXPORT_SYMBOL(__copy_from_user_ll_nozero);
unsigned long __copy_from_user_ll_nocache(void *to, const void __user *from,
unsigned long n)
{
#ifdef CONFIG_X86_INTEL_USERCOPY
if (n > 64 && cpu_has_xmm2)
n = __copy_user_zeroing_intel_nocache(to, from, n);
else
__copy_user_zeroing(to, from, n);
#else
__copy_user_zeroing(to, from, n);
#endif
return n;
}
EXPORT_SYMBOL(__copy_from_user_ll_nocache);
unsigned long __copy_from_user_ll_nocache_nozero(void *to, const void __user *from,
unsigned long n)
{
#ifdef CONFIG_X86_INTEL_USERCOPY
if (n > 64 && cpu_has_xmm2)
n = __copy_user_intel_nocache(to, from, n);
else
__copy_user(to, from, n);
#else
__copy_user(to, from, n);
#endif
return n;
}
EXPORT_SYMBOL(__copy_from_user_ll_nocache_nozero);
/**
* copy_to_user: - Copy a block of data into user space.
* @to: Destination address, in user space.
* @from: Source address, in kernel space.
* @n: Number of bytes to copy.
*
* Context: User context only. This function may sleep.
*
* Copy data from kernel space to user space.
*
* Returns number of bytes that could not be copied.
* On success, this will be zero.
*/
unsigned long
copy_to_user(void __user *to, const void *from, unsigned long n)
{
if (access_ok(VERIFY_WRITE, to, n))
n = __copy_to_user(to, from, n);
return n;
}
EXPORT_SYMBOL(copy_to_user);
/**
* copy_from_user: - Copy a block of data from user space.
* @to: Destination address, in kernel space.
* @from: Source address, in user space.
* @n: Number of bytes to copy.
*
* Context: User context only. This function may sleep.
*
* Copy data from user space to kernel space.
*
* Returns number of bytes that could not be copied.
* On success, this will be zero.
*
* If some data could not be copied, this function will pad the copied
* data to the requested size using zero bytes.
*/
unsigned long
_copy_from_user(void *to, const void __user *from, unsigned long n)
{
if (access_ok(VERIFY_READ, from, n))
n = __copy_from_user(to, from, n);
else
memset(to, 0, n);
return n;
}
EXPORT_SYMBOL(_copy_from_user);
void copy_from_user_overflow(void)
{
WARN(1, "Buffer overflow detected!\n");
}
EXPORT_SYMBOL(copy_from_user_overflow);
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