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DEFINITIONS
This source file includes following definitions.
- __do_strncpy_from_user
- strnlen_user
/*
* Authors: Hans-Peter Nilsson (hp@axis.com)
*
*/
#ifndef _CRIS_ARCH_UACCESS_H
#define _CRIS_ARCH_UACCESS_H
/*
* We don't tell gcc that we are accessing memory, but this is OK
* because we do not write to any memory gcc knows about, so there
* are no aliasing issues.
*
* Note that PC at a fault is the address *at* the faulting
* instruction for CRISv32.
*/
#define __put_user_asm(x, addr, err, op) \
__asm__ __volatile__( \
"2: "op" %1,[%2]\n" \
"4:\n" \
" .section .fixup,\"ax\"\n" \
"3: move.d %3,%0\n" \
" jump 4b\n" \
" nop\n" \
" .previous\n" \
" .section __ex_table,\"a\"\n" \
" .dword 2b,3b\n" \
" .previous\n" \
: "=r" (err) \
: "r" (x), "r" (addr), "g" (-EFAULT), "0" (err))
#define __put_user_asm_64(x, addr, err) do { \
int dummy_for_put_user_asm_64_; \
__asm__ __volatile__( \
"2: move.d %M2,[%1+]\n" \
"4: move.d %H2,[%1]\n" \
"5:\n" \
" .section .fixup,\"ax\"\n" \
"3: move.d %4,%0\n" \
" jump 5b\n" \
" .previous\n" \
" .section __ex_table,\"a\"\n" \
" .dword 2b,3b\n" \
" .dword 4b,3b\n" \
" .previous\n" \
: "=r" (err), "=b" (dummy_for_put_user_asm_64_) \
: "r" (x), "1" (addr), "g" (-EFAULT), \
"0" (err)); \
} while (0)
/* See comment before __put_user_asm. */
#define __get_user_asm(x, addr, err, op) \
__asm__ __volatile__( \
"2: "op" [%2],%1\n" \
"4:\n" \
" .section .fixup,\"ax\"\n" \
"3: move.d %3,%0\n" \
" jump 4b\n" \
" moveq 0,%1\n" \
" .previous\n" \
" .section __ex_table,\"a\"\n" \
" .dword 2b,3b\n" \
" .previous\n" \
: "=r" (err), "=r" (x) \
: "r" (addr), "g" (-EFAULT), "0" (err))
#define __get_user_asm_64(x, addr, err) do { \
int dummy_for_get_user_asm_64_; \
__asm__ __volatile__( \
"2: move.d [%2+],%M1\n" \
"4: move.d [%2],%H1\n" \
"5:\n" \
" .section .fixup,\"ax\"\n" \
"3: move.d %4,%0\n" \
" jump 5b\n" \
" moveq 0,%1\n" \
" .previous\n" \
" .section __ex_table,\"a\"\n" \
" .dword 2b,3b\n" \
" .dword 4b,3b\n" \
" .previous\n" \
: "=r" (err), "=r" (x), \
"=b" (dummy_for_get_user_asm_64_) \
: "2" (addr), "g" (-EFAULT), "0" (err));\
} while (0)
/*
* Copy a null terminated string from userspace.
*
* Must return:
* -EFAULT for an exception
* count if we hit the buffer limit
* bytes copied if we hit a null byte
* (without the null byte)
*/
static inline long
__do_strncpy_from_user(char *dst, const char *src, long count)
{
long res;
if (count == 0)
return 0;
/*
* Currently, in 2.4.0-test9, most ports use a simple byte-copy loop.
* So do we.
*
* This code is deduced from:
*
* char tmp2;
* long tmp1, tmp3;
* tmp1 = count;
* while ((*dst++ = (tmp2 = *src++)) != 0
* && --tmp1)
* ;
*
* res = count - tmp1;
*
* with tweaks.
*/
__asm__ __volatile__ (
" move.d %3,%0\n"
"5: move.b [%2+],$acr\n"
"1: beq 2f\n"
" move.b $acr,[%1+]\n"
" subq 1,%0\n"
"2: bne 1b\n"
" move.b [%2+],$acr\n"
" sub.d %3,%0\n"
" neg.d %0,%0\n"
"3:\n"
" .section .fixup,\"ax\"\n"
"4: move.d %7,%0\n"
" jump 3b\n"
" nop\n"
/* The address for a fault at the first move is trivial.
The address for a fault at the second move is that of
the preceding branch insn, since the move insn is in
its delay-slot. That address is also a branch
target. Just so you don't get confused... */
" .previous\n"
" .section __ex_table,\"a\"\n"
" .dword 5b,4b\n"
" .dword 2b,4b\n"
" .previous"
: "=r" (res), "=b" (dst), "=b" (src), "=r" (count)
: "3" (count), "1" (dst), "2" (src), "g" (-EFAULT)
: "acr");
return res;
}
/* A few copy asms to build up the more complex ones from.
Note again, a post-increment is performed regardless of whether a bus
fault occurred in that instruction, and PC for a faulted insn is the
address for the insn, or for the preceding branch when in a delay-slot. */
#define __asm_copy_user_cont(to, from, ret, COPY, FIXUP, TENTRY) \
__asm__ __volatile__ ( \
COPY \
"1:\n" \
" .section .fixup,\"ax\"\n" \
FIXUP \
" .previous\n" \
" .section __ex_table,\"a\"\n" \
TENTRY \
" .previous\n" \
: "=b" (to), "=b" (from), "=r" (ret) \
: "0" (to), "1" (from), "2" (ret) \
: "acr", "memory")
#define __asm_copy_from_user_1(to, from, ret) \
__asm_copy_user_cont(to, from, ret, \
"2: move.b [%1+],$acr\n" \
" move.b $acr,[%0+]\n", \
"3: addq 1,%2\n" \
" jump 1b\n" \
" clear.b [%0+]\n", \
" .dword 2b,3b\n")
#define __asm_copy_from_user_2x_cont(to, from, ret, COPY, FIXUP, TENTRY) \
__asm_copy_user_cont(to, from, ret, \
COPY \
"2: move.w [%1+],$acr\n" \
" move.w $acr,[%0+]\n", \
FIXUP \
"3: addq 2,%2\n" \
" jump 1b\n" \
" clear.w [%0+]\n", \
TENTRY \
" .dword 2b,3b\n")
#define __asm_copy_from_user_2(to, from, ret) \
__asm_copy_from_user_2x_cont(to, from, ret, "", "", "")
#define __asm_copy_from_user_3(to, from, ret) \
__asm_copy_from_user_2x_cont(to, from, ret, \
"4: move.b [%1+],$acr\n" \
" move.b $acr,[%0+]\n", \
"5: addq 1,%2\n" \
" clear.b [%0+]\n", \
" .dword 4b,5b\n")
#define __asm_copy_from_user_4x_cont(to, from, ret, COPY, FIXUP, TENTRY) \
__asm_copy_user_cont(to, from, ret, \
COPY \
"2: move.d [%1+],$acr\n" \
" move.d $acr,[%0+]\n", \
FIXUP \
"3: addq 4,%2\n" \
" jump 1b\n" \
" clear.d [%0+]\n", \
TENTRY \
" .dword 2b,3b\n")
#define __asm_copy_from_user_4(to, from, ret) \
__asm_copy_from_user_4x_cont(to, from, ret, "", "", "")
#define __asm_copy_from_user_5(to, from, ret) \
__asm_copy_from_user_4x_cont(to, from, ret, \
"4: move.b [%1+],$acr\n" \
" move.b $acr,[%0+]\n", \
"5: addq 1,%2\n" \
" clear.b [%0+]\n", \
" .dword 4b,5b\n")
#define __asm_copy_from_user_6x_cont(to, from, ret, COPY, FIXUP, TENTRY) \
__asm_copy_from_user_4x_cont(to, from, ret, \
COPY \
"4: move.w [%1+],$acr\n" \
" move.w $acr,[%0+]\n", \
FIXUP \
"5: addq 2,%2\n" \
" clear.w [%0+]\n", \
TENTRY \
" .dword 4b,5b\n")
#define __asm_copy_from_user_6(to, from, ret) \
__asm_copy_from_user_6x_cont(to, from, ret, "", "", "")
#define __asm_copy_from_user_7(to, from, ret) \
__asm_copy_from_user_6x_cont(to, from, ret, \
"6: move.b [%1+],$acr\n" \
" move.b $acr,[%0+]\n", \
"7: addq 1,%2\n" \
" clear.b [%0+]\n", \
" .dword 6b,7b\n")
#define __asm_copy_from_user_8x_cont(to, from, ret, COPY, FIXUP, TENTRY) \
__asm_copy_from_user_4x_cont(to, from, ret, \
COPY \
"4: move.d [%1+],$acr\n" \
" move.d $acr,[%0+]\n", \
FIXUP \
"5: addq 4,%2\n" \
" clear.d [%0+]\n", \
TENTRY \
" .dword 4b,5b\n")
#define __asm_copy_from_user_8(to, from, ret) \
__asm_copy_from_user_8x_cont(to, from, ret, "", "", "")
#define __asm_copy_from_user_9(to, from, ret) \
__asm_copy_from_user_8x_cont(to, from, ret, \
"6: move.b [%1+],$acr\n" \
" move.b $acr,[%0+]\n", \
"7: addq 1,%2\n" \
" clear.b [%0+]\n", \
" .dword 6b,7b\n")
#define __asm_copy_from_user_10x_cont(to, from, ret, COPY, FIXUP, TENTRY) \
__asm_copy_from_user_8x_cont(to, from, ret, \
COPY \
"6: move.w [%1+],$acr\n" \
" move.w $acr,[%0+]\n", \
FIXUP \
"7: addq 2,%2\n" \
" clear.w [%0+]\n", \
TENTRY \
" .dword 6b,7b\n")
#define __asm_copy_from_user_10(to, from, ret) \
__asm_copy_from_user_10x_cont(to, from, ret, "", "", "")
#define __asm_copy_from_user_11(to, from, ret) \
__asm_copy_from_user_10x_cont(to, from, ret, \
"8: move.b [%1+],$acr\n" \
" move.b $acr,[%0+]\n", \
"9: addq 1,%2\n" \
" clear.b [%0+]\n", \
" .dword 8b,9b\n")
#define __asm_copy_from_user_12x_cont(to, from, ret, COPY, FIXUP, TENTRY) \
__asm_copy_from_user_8x_cont(to, from, ret, \
COPY \
"6: move.d [%1+],$acr\n" \
" move.d $acr,[%0+]\n", \
FIXUP \
"7: addq 4,%2\n" \
" clear.d [%0+]\n", \
TENTRY \
" .dword 6b,7b\n")
#define __asm_copy_from_user_12(to, from, ret) \
__asm_copy_from_user_12x_cont(to, from, ret, "", "", "")
#define __asm_copy_from_user_13(to, from, ret) \
__asm_copy_from_user_12x_cont(to, from, ret, \
"8: move.b [%1+],$acr\n" \
" move.b $acr,[%0+]\n", \
"9: addq 1,%2\n" \
" clear.b [%0+]\n", \
" .dword 8b,9b\n")
#define __asm_copy_from_user_14x_cont(to, from, ret, COPY, FIXUP, TENTRY) \
__asm_copy_from_user_12x_cont(to, from, ret, \
COPY \
"8: move.w [%1+],$acr\n" \
" move.w $acr,[%0+]\n", \
FIXUP \
"9: addq 2,%2\n" \
" clear.w [%0+]\n", \
TENTRY \
" .dword 8b,9b\n")
#define __asm_copy_from_user_14(to, from, ret) \
__asm_copy_from_user_14x_cont(to, from, ret, "", "", "")
#define __asm_copy_from_user_15(to, from, ret) \
__asm_copy_from_user_14x_cont(to, from, ret, \
"10: move.b [%1+],$acr\n" \
" move.b $acr,[%0+]\n", \
"11: addq 1,%2\n" \
" clear.b [%0+]\n", \
" .dword 10b,11b\n")
#define __asm_copy_from_user_16x_cont(to, from, ret, COPY, FIXUP, TENTRY) \
__asm_copy_from_user_12x_cont(to, from, ret, \
COPY \
"8: move.d [%1+],$acr\n" \
" move.d $acr,[%0+]\n", \
FIXUP \
"9: addq 4,%2\n" \
" clear.d [%0+]\n", \
TENTRY \
" .dword 8b,9b\n")
#define __asm_copy_from_user_16(to, from, ret) \
__asm_copy_from_user_16x_cont(to, from, ret, "", "", "")
#define __asm_copy_from_user_20x_cont(to, from, ret, COPY, FIXUP, TENTRY) \
__asm_copy_from_user_16x_cont(to, from, ret, \
COPY \
"10: move.d [%1+],$acr\n" \
" move.d $acr,[%0+]\n", \
FIXUP \
"11: addq 4,%2\n" \
" clear.d [%0+]\n", \
TENTRY \
" .dword 10b,11b\n")
#define __asm_copy_from_user_20(to, from, ret) \
__asm_copy_from_user_20x_cont(to, from, ret, "", "", "")
#define __asm_copy_from_user_24x_cont(to, from, ret, COPY, FIXUP, TENTRY) \
__asm_copy_from_user_20x_cont(to, from, ret, \
COPY \
"12: move.d [%1+],$acr\n" \
" move.d $acr,[%0+]\n", \
FIXUP \
"13: addq 4,%2\n" \
" clear.d [%0+]\n", \
TENTRY \
" .dword 12b,13b\n")
#define __asm_copy_from_user_24(to, from, ret) \
__asm_copy_from_user_24x_cont(to, from, ret, "", "", "")
/* And now, the to-user ones. */
#define __asm_copy_to_user_1(to, from, ret) \
__asm_copy_user_cont(to, from, ret, \
" move.b [%1+],$acr\n" \
"2: move.b $acr,[%0+]\n", \
"3: jump 1b\n" \
" addq 1,%2\n", \
" .dword 2b,3b\n")
#define __asm_copy_to_user_2x_cont(to, from, ret, COPY, FIXUP, TENTRY) \
__asm_copy_user_cont(to, from, ret, \
COPY \
" move.w [%1+],$acr\n" \
"2: move.w $acr,[%0+]\n", \
FIXUP \
"3: jump 1b\n" \
" addq 2,%2\n", \
TENTRY \
" .dword 2b,3b\n")
#define __asm_copy_to_user_2(to, from, ret) \
__asm_copy_to_user_2x_cont(to, from, ret, "", "", "")
#define __asm_copy_to_user_3(to, from, ret) \
__asm_copy_to_user_2x_cont(to, from, ret, \
" move.b [%1+],$acr\n" \
"4: move.b $acr,[%0+]\n", \
"5: addq 1,%2\n", \
" .dword 4b,5b\n")
#define __asm_copy_to_user_4x_cont(to, from, ret, COPY, FIXUP, TENTRY) \
__asm_copy_user_cont(to, from, ret, \
COPY \
" move.d [%1+],$acr\n" \
"2: move.d $acr,[%0+]\n", \
FIXUP \
"3: jump 1b\n" \
" addq 4,%2\n", \
TENTRY \
" .dword 2b,3b\n")
#define __asm_copy_to_user_4(to, from, ret) \
__asm_copy_to_user_4x_cont(to, from, ret, "", "", "")
#define __asm_copy_to_user_5(to, from, ret) \
__asm_copy_to_user_4x_cont(to, from, ret, \
" move.b [%1+],$acr\n" \
"4: move.b $acr,[%0+]\n", \
"5: addq 1,%2\n", \
" .dword 4b,5b\n")
#define __asm_copy_to_user_6x_cont(to, from, ret, COPY, FIXUP, TENTRY) \
__asm_copy_to_user_4x_cont(to, from, ret, \
COPY \
" move.w [%1+],$acr\n" \
"4: move.w $acr,[%0+]\n", \
FIXUP \
"5: addq 2,%2\n", \
TENTRY \
" .dword 4b,5b\n")
#define __asm_copy_to_user_6(to, from, ret) \
__asm_copy_to_user_6x_cont(to, from, ret, "", "", "")
#define __asm_copy_to_user_7(to, from, ret) \
__asm_copy_to_user_6x_cont(to, from, ret, \
" move.b [%1+],$acr\n" \
"6: move.b $acr,[%0+]\n", \
"7: addq 1,%2\n", \
" .dword 6b,7b\n")
#define __asm_copy_to_user_8x_cont(to, from, ret, COPY, FIXUP, TENTRY) \
__asm_copy_to_user_4x_cont(to, from, ret, \
COPY \
" move.d [%1+],$acr\n" \
"4: move.d $acr,[%0+]\n", \
FIXUP \
"5: addq 4,%2\n", \
TENTRY \
" .dword 4b,5b\n")
#define __asm_copy_to_user_8(to, from, ret) \
__asm_copy_to_user_8x_cont(to, from, ret, "", "", "")
#define __asm_copy_to_user_9(to, from, ret) \
__asm_copy_to_user_8x_cont(to, from, ret, \
" move.b [%1+],$acr\n" \
"6: move.b $acr,[%0+]\n", \
"7: addq 1,%2\n", \
" .dword 6b,7b\n")
#define __asm_copy_to_user_10x_cont(to, from, ret, COPY, FIXUP, TENTRY) \
__asm_copy_to_user_8x_cont(to, from, ret, \
COPY \
" move.w [%1+],$acr\n" \
"6: move.w $acr,[%0+]\n", \
FIXUP \
"7: addq 2,%2\n", \
TENTRY \
" .dword 6b,7b\n")
#define __asm_copy_to_user_10(to, from, ret) \
__asm_copy_to_user_10x_cont(to, from, ret, "", "", "")
#define __asm_copy_to_user_11(to, from, ret) \
__asm_copy_to_user_10x_cont(to, from, ret, \
" move.b [%1+],$acr\n" \
"8: move.b $acr,[%0+]\n", \
"9: addq 1,%2\n", \
" .dword 8b,9b\n")
#define __asm_copy_to_user_12x_cont(to, from, ret, COPY, FIXUP, TENTRY) \
__asm_copy_to_user_8x_cont(to, from, ret, \
COPY \
" move.d [%1+],$acr\n" \
"6: move.d $acr,[%0+]\n", \
FIXUP \
"7: addq 4,%2\n", \
TENTRY \
" .dword 6b,7b\n")
#define __asm_copy_to_user_12(to, from, ret) \
__asm_copy_to_user_12x_cont(to, from, ret, "", "", "")
#define __asm_copy_to_user_13(to, from, ret) \
__asm_copy_to_user_12x_cont(to, from, ret, \
" move.b [%1+],$acr\n" \
"8: move.b $acr,[%0+]\n", \
"9: addq 1,%2\n", \
" .dword 8b,9b\n")
#define __asm_copy_to_user_14x_cont(to, from, ret, COPY, FIXUP, TENTRY) \
__asm_copy_to_user_12x_cont(to, from, ret, \
COPY \
" move.w [%1+],$acr\n" \
"8: move.w $acr,[%0+]\n", \
FIXUP \
"9: addq 2,%2\n", \
TENTRY \
" .dword 8b,9b\n")
#define __asm_copy_to_user_14(to, from, ret) \
__asm_copy_to_user_14x_cont(to, from, ret, "", "", "")
#define __asm_copy_to_user_15(to, from, ret) \
__asm_copy_to_user_14x_cont(to, from, ret, \
" move.b [%1+],$acr\n" \
"10: move.b $acr,[%0+]\n", \
"11: addq 1,%2\n", \
" .dword 10b,11b\n")
#define __asm_copy_to_user_16x_cont(to, from, ret, COPY, FIXUP, TENTRY) \
__asm_copy_to_user_12x_cont(to, from, ret, \
COPY \
" move.d [%1+],$acr\n" \
"8: move.d $acr,[%0+]\n", \
FIXUP \
"9: addq 4,%2\n", \
TENTRY \
" .dword 8b,9b\n")
#define __asm_copy_to_user_16(to, from, ret) \
__asm_copy_to_user_16x_cont(to, from, ret, "", "", "")
#define __asm_copy_to_user_20x_cont(to, from, ret, COPY, FIXUP, TENTRY) \
__asm_copy_to_user_16x_cont(to, from, ret, \
COPY \
" move.d [%1+],$acr\n" \
"10: move.d $acr,[%0+]\n", \
FIXUP \
"11: addq 4,%2\n", \
TENTRY \
" .dword 10b,11b\n")
#define __asm_copy_to_user_20(to, from, ret) \
__asm_copy_to_user_20x_cont(to, from, ret, "", "", "")
#define __asm_copy_to_user_24x_cont(to, from, ret, COPY, FIXUP, TENTRY) \
__asm_copy_to_user_20x_cont(to, from, ret, \
COPY \
" move.d [%1+],$acr\n" \
"12: move.d $acr,[%0+]\n", \
FIXUP \
"13: addq 4,%2\n", \
TENTRY \
" .dword 12b,13b\n")
#define __asm_copy_to_user_24(to, from, ret) \
__asm_copy_to_user_24x_cont(to, from, ret, "", "", "")
/* Define a few clearing asms with exception handlers. */
/* This frame-asm is like the __asm_copy_user_cont one, but has one less
input. */
#define __asm_clear(to, ret, CLEAR, FIXUP, TENTRY) \
__asm__ __volatile__ ( \
CLEAR \
"1:\n" \
" .section .fixup,\"ax\"\n" \
FIXUP \
" .previous\n" \
" .section __ex_table,\"a\"\n" \
TENTRY \
" .previous" \
: "=b" (to), "=r" (ret) \
: "0" (to), "1" (ret) \
: "memory")
#define __asm_clear_1(to, ret) \
__asm_clear(to, ret, \
"2: clear.b [%0+]\n", \
"3: jump 1b\n" \
" addq 1,%1\n", \
" .dword 2b,3b\n")
#define __asm_clear_2(to, ret) \
__asm_clear(to, ret, \
"2: clear.w [%0+]\n", \
"3: jump 1b\n" \
" addq 2,%1\n", \
" .dword 2b,3b\n")
#define __asm_clear_3(to, ret) \
__asm_clear(to, ret, \
"2: clear.w [%0+]\n" \
"3: clear.b [%0+]\n", \
"4: addq 2,%1\n" \
"5: jump 1b\n" \
" addq 1,%1\n", \
" .dword 2b,4b\n" \
" .dword 3b,5b\n")
#define __asm_clear_4x_cont(to, ret, CLEAR, FIXUP, TENTRY) \
__asm_clear(to, ret, \
CLEAR \
"2: clear.d [%0+]\n", \
FIXUP \
"3: jump 1b\n" \
" addq 4,%1\n", \
TENTRY \
" .dword 2b,3b\n")
#define __asm_clear_4(to, ret) \
__asm_clear_4x_cont(to, ret, "", "", "")
#define __asm_clear_8x_cont(to, ret, CLEAR, FIXUP, TENTRY) \
__asm_clear_4x_cont(to, ret, \
CLEAR \
"4: clear.d [%0+]\n", \
FIXUP \
"5: addq 4,%1\n", \
TENTRY \
" .dword 4b,5b\n")
#define __asm_clear_8(to, ret) \
__asm_clear_8x_cont(to, ret, "", "", "")
#define __asm_clear_12x_cont(to, ret, CLEAR, FIXUP, TENTRY) \
__asm_clear_8x_cont(to, ret, \
CLEAR \
"6: clear.d [%0+]\n", \
FIXUP \
"7: addq 4,%1\n", \
TENTRY \
" .dword 6b,7b\n")
#define __asm_clear_12(to, ret) \
__asm_clear_12x_cont(to, ret, "", "", "")
#define __asm_clear_16x_cont(to, ret, CLEAR, FIXUP, TENTRY) \
__asm_clear_12x_cont(to, ret, \
CLEAR \
"8: clear.d [%0+]\n", \
FIXUP \
"9: addq 4,%1\n", \
TENTRY \
" .dword 8b,9b\n")
#define __asm_clear_16(to, ret) \
__asm_clear_16x_cont(to, ret, "", "", "")
#define __asm_clear_20x_cont(to, ret, CLEAR, FIXUP, TENTRY) \
__asm_clear_16x_cont(to, ret, \
CLEAR \
"10: clear.d [%0+]\n", \
FIXUP \
"11: addq 4,%1\n", \
TENTRY \
" .dword 10b,11b\n")
#define __asm_clear_20(to, ret) \
__asm_clear_20x_cont(to, ret, "", "", "")
#define __asm_clear_24x_cont(to, ret, CLEAR, FIXUP, TENTRY) \
__asm_clear_20x_cont(to, ret, \
CLEAR \
"12: clear.d [%0+]\n", \
FIXUP \
"13: addq 4,%1\n", \
TENTRY \
" .dword 12b,13b\n")
#define __asm_clear_24(to, ret) \
__asm_clear_24x_cont(to, ret, "", "", "")
/*
* Return the size of a string (including the ending 0)
*
* Return length of string in userspace including terminating 0
* or 0 for error. Return a value greater than N if too long.
*/
static inline long
strnlen_user(const char *s, long n)
{
long res, tmp1;
if (!access_ok(VERIFY_READ, s, 0))
return 0;
/*
* This code is deduced from:
*
* tmp1 = n;
* while (tmp1-- > 0 && *s++)
* ;
*
* res = n - tmp1;
*
* (with tweaks).
*/
__asm__ __volatile__ (
" move.d %1,$acr\n"
" cmpq 0,$acr\n"
"0:\n"
" ble 1f\n"
" subq 1,$acr\n"
"4: test.b [%0+]\n"
" bne 0b\n"
" cmpq 0,$acr\n"
"1:\n"
" move.d %1,%0\n"
" sub.d $acr,%0\n"
"2:\n"
" .section .fixup,\"ax\"\n"
"3: jump 2b\n"
" clear.d %0\n"
" .previous\n"
" .section __ex_table,\"a\"\n"
" .dword 4b,3b\n"
" .previous\n"
: "=r" (res), "=r" (tmp1)
: "0" (s), "1" (n)
: "acr");
return res;
}
#endif