mirror of
https://github.com/torvalds/linux.git
synced 2024-11-16 17:12:06 +00:00
1da177e4c3
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
637 lines
18 KiB
C
637 lines
18 KiB
C
/*
|
|
* 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/config.h>
|
|
#include <linux/mm.h>
|
|
#include <linux/highmem.h>
|
|
#include <linux/blkdev.h>
|
|
#include <linux/module.h>
|
|
#include <asm/uaccess.h>
|
|
#include <asm/mmx.h>
|
|
|
|
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))
|
|
|
|
/*
|
|
* Copy a null terminated string from userspace.
|
|
*/
|
|
|
|
#define __do_strncpy_from_user(dst,src,count,res) \
|
|
do { \
|
|
int __d0, __d1, __d2; \
|
|
might_sleep(); \
|
|
__asm__ __volatile__( \
|
|
" testl %1,%1\n" \
|
|
" jz 2f\n" \
|
|
"0: lodsb\n" \
|
|
" stosb\n" \
|
|
" testb %%al,%%al\n" \
|
|
" jz 1f\n" \
|
|
" decl %1\n" \
|
|
" jnz 0b\n" \
|
|
"1: subl %1,%0\n" \
|
|
"2:\n" \
|
|
".section .fixup,\"ax\"\n" \
|
|
"3: movl %5,%0\n" \
|
|
" jmp 2b\n" \
|
|
".previous\n" \
|
|
".section __ex_table,\"a\"\n" \
|
|
" .align 4\n" \
|
|
" .long 0b,3b\n" \
|
|
".previous" \
|
|
: "=d"(res), "=c"(count), "=&a" (__d0), "=&S" (__d1), \
|
|
"=&D" (__d2) \
|
|
: "i"(-EFAULT), "0"(count), "1"(count), "3"(src), "4"(dst) \
|
|
: "memory"); \
|
|
} while (0)
|
|
|
|
/**
|
|
* __strncpy_from_user: - Copy a NUL terminated string from userspace, with less checking.
|
|
* @dst: Destination address, in kernel space. This buffer must be at
|
|
* least @count bytes long.
|
|
* @src: Source address, in user space.
|
|
* @count: Maximum number of bytes to copy, including the trailing NUL.
|
|
*
|
|
* Copies a NUL-terminated string from userspace to kernel space.
|
|
* Caller must check the specified block with access_ok() before calling
|
|
* this function.
|
|
*
|
|
* On success, returns the length of the string (not including the trailing
|
|
* NUL).
|
|
*
|
|
* If access to userspace fails, returns -EFAULT (some data may have been
|
|
* copied).
|
|
*
|
|
* If @count is smaller than the length of the string, copies @count bytes
|
|
* and returns @count.
|
|
*/
|
|
long
|
|
__strncpy_from_user(char *dst, const char __user *src, long count)
|
|
{
|
|
long res;
|
|
__do_strncpy_from_user(dst, src, count, res);
|
|
return res;
|
|
}
|
|
|
|
/**
|
|
* strncpy_from_user: - Copy a NUL terminated string from userspace.
|
|
* @dst: Destination address, in kernel space. This buffer must be at
|
|
* least @count bytes long.
|
|
* @src: Source address, in user space.
|
|
* @count: Maximum number of bytes to copy, including the trailing NUL.
|
|
*
|
|
* Copies a NUL-terminated string from userspace to kernel space.
|
|
*
|
|
* On success, returns the length of the string (not including the trailing
|
|
* NUL).
|
|
*
|
|
* If access to userspace fails, returns -EFAULT (some data may have been
|
|
* copied).
|
|
*
|
|
* If @count is smaller than the length of the string, copies @count bytes
|
|
* and returns @count.
|
|
*/
|
|
long
|
|
strncpy_from_user(char *dst, const char __user *src, long count)
|
|
{
|
|
long res = -EFAULT;
|
|
if (access_ok(VERIFY_READ, src, 1))
|
|
__do_strncpy_from_user(dst, src, count, res);
|
|
return res;
|
|
}
|
|
|
|
|
|
/*
|
|
* Zero Userspace
|
|
*/
|
|
|
|
#define __do_clear_user(addr,size) \
|
|
do { \
|
|
int __d0; \
|
|
might_sleep(); \
|
|
__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" \
|
|
".section __ex_table,\"a\"\n" \
|
|
" .align 4\n" \
|
|
" .long 0b,3b\n" \
|
|
" .long 1b,2b\n" \
|
|
".previous" \
|
|
: "=&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_sleep();
|
|
if (access_ok(VERIFY_WRITE, to, n))
|
|
__do_clear_user(to, n);
|
|
return n;
|
|
}
|
|
|
|
/**
|
|
* __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;
|
|
}
|
|
|
|
/**
|
|
* strlen_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_sleep();
|
|
|
|
__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;
|
|
}
|
|
|
|
#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;
|
|
}
|
|
#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);
|
|
#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)
|
|
{
|
|
BUG_ON((long) n < 0);
|
|
#ifndef CONFIG_X86_WP_WORKS_OK
|
|
if (unlikely(boot_cpu_data.wp_works_ok == 0) &&
|
|
((unsigned long )to) < TASK_SIZE) {
|
|
/*
|
|
* 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(¤t->mm->mmap_sem);
|
|
retval = get_user_pages(current, current->mm,
|
|
(unsigned long )to, 1, 1, 0, &pg, NULL);
|
|
|
|
if (retval == -ENOMEM && current->pid == 1) {
|
|
up_read(¤t->mm->mmap_sem);
|
|
blk_congestion_wait(WRITE, HZ/50);
|
|
goto survive;
|
|
}
|
|
|
|
if (retval != 1) {
|
|
up_read(¤t->mm->mmap_sem);
|
|
break;
|
|
}
|
|
|
|
maddr = kmap_atomic(pg, KM_USER0);
|
|
memcpy(maddr + offset, from, len);
|
|
kunmap_atomic(maddr, KM_USER0);
|
|
set_page_dirty_lock(pg);
|
|
put_page(pg);
|
|
up_read(¤t->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;
|
|
}
|
|
|
|
unsigned long
|
|
__copy_from_user_ll(void *to, const void __user *from, unsigned long n)
|
|
{
|
|
BUG_ON((long)n < 0);
|
|
if (movsl_is_ok(to, from, n))
|
|
__copy_user_zeroing(to, from, n);
|
|
else
|
|
n = __copy_user_zeroing_intel(to, from, n);
|
|
return n;
|
|
}
|
|
|
|
/**
|
|
* 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)
|
|
{
|
|
might_sleep();
|
|
BUG_ON((long) n < 0);
|
|
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)
|
|
{
|
|
might_sleep();
|
|
BUG_ON((long) n < 0);
|
|
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);
|