226 lines
5.6 KiB
ArmAsm
226 lines
5.6 KiB
ArmAsm
/*
|
|
* arch/xtensa/lib/strncpy_user.S
|
|
*
|
|
* This file is subject to the terms and conditions of the GNU General
|
|
* Public License. See the file "COPYING" in the main directory of
|
|
* this archive for more details.
|
|
*
|
|
* Returns: -EFAULT if exception before terminator, N if the entire
|
|
* buffer filled, else strlen.
|
|
*
|
|
* Copyright (C) 2002 Tensilica Inc.
|
|
*/
|
|
|
|
#include <variant/core.h>
|
|
#include <linux/errno.h>
|
|
|
|
/* Load or store instructions that may cause exceptions use the EX macro. */
|
|
|
|
#define EX(insn,reg1,reg2,offset,handler) \
|
|
9: insn reg1, reg2, offset; \
|
|
.section __ex_table, "a"; \
|
|
.word 9b, handler; \
|
|
.previous
|
|
|
|
/*
|
|
* char *__strncpy_user(char *dst, const char *src, size_t len)
|
|
*/
|
|
|
|
#ifdef __XTENSA_EB__
|
|
# define MASK0 0xff000000
|
|
# define MASK1 0x00ff0000
|
|
# define MASK2 0x0000ff00
|
|
# define MASK3 0x000000ff
|
|
#else
|
|
# define MASK0 0x000000ff
|
|
# define MASK1 0x0000ff00
|
|
# define MASK2 0x00ff0000
|
|
# define MASK3 0xff000000
|
|
#endif
|
|
|
|
# Register use
|
|
# a0/ return address
|
|
# a1/ stack pointer
|
|
# a2/ return value
|
|
# a3/ src
|
|
# a4/ len
|
|
# a5/ mask0
|
|
# a6/ mask1
|
|
# a7/ mask2
|
|
# a8/ mask3
|
|
# a9/ tmp
|
|
# a10/ tmp
|
|
# a11/ dst
|
|
# a12/ tmp
|
|
|
|
.text
|
|
.align 4
|
|
.global __strncpy_user
|
|
.type __strncpy_user,@function
|
|
__strncpy_user:
|
|
entry sp, 16 # minimal stack frame
|
|
# a2/ dst, a3/ src, a4/ len
|
|
mov a11, a2 # leave dst in return value register
|
|
beqz a4, .Lret # if len is zero
|
|
movi a5, MASK0 # mask for byte 0
|
|
movi a6, MASK1 # mask for byte 1
|
|
movi a7, MASK2 # mask for byte 2
|
|
movi a8, MASK3 # mask for byte 3
|
|
bbsi.l a3, 0, .Lsrc1mod2 # if only 8-bit aligned
|
|
bbsi.l a3, 1, .Lsrc2mod4 # if only 16-bit aligned
|
|
.Lsrcaligned: # return here when src is word-aligned
|
|
srli a12, a4, 2 # number of loop iterations with 4B per loop
|
|
movi a9, 3
|
|
bnone a11, a9, .Laligned
|
|
j .Ldstunaligned
|
|
|
|
.Lsrc1mod2: # src address is odd
|
|
EX(l8ui, a9, a3, 0, fixup_l) # get byte 0
|
|
addi a3, a3, 1 # advance src pointer
|
|
EX(s8i, a9, a11, 0, fixup_s) # store byte 0
|
|
beqz a9, .Lret # if byte 0 is zero
|
|
addi a11, a11, 1 # advance dst pointer
|
|
addi a4, a4, -1 # decrement len
|
|
beqz a4, .Lret # if len is zero
|
|
bbci.l a3, 1, .Lsrcaligned # if src is now word-aligned
|
|
|
|
.Lsrc2mod4: # src address is 2 mod 4
|
|
EX(l8ui, a9, a3, 0, fixup_l) # get byte 0
|
|
/* 1-cycle interlock */
|
|
EX(s8i, a9, a11, 0, fixup_s) # store byte 0
|
|
beqz a9, .Lret # if byte 0 is zero
|
|
addi a11, a11, 1 # advance dst pointer
|
|
addi a4, a4, -1 # decrement len
|
|
beqz a4, .Lret # if len is zero
|
|
EX(l8ui, a9, a3, 1, fixup_l) # get byte 0
|
|
addi a3, a3, 2 # advance src pointer
|
|
EX(s8i, a9, a11, 0, fixup_s) # store byte 0
|
|
beqz a9, .Lret # if byte 0 is zero
|
|
addi a11, a11, 1 # advance dst pointer
|
|
addi a4, a4, -1 # decrement len
|
|
bnez a4, .Lsrcaligned # if len is nonzero
|
|
.Lret:
|
|
sub a2, a11, a2 # compute strlen
|
|
retw
|
|
|
|
/*
|
|
* dst is word-aligned, src is word-aligned
|
|
*/
|
|
.align 4 # 1 mod 4 alignment for LOOPNEZ
|
|
.byte 0 # (0 mod 4 alignment for LBEG)
|
|
.Laligned:
|
|
#if XCHAL_HAVE_LOOPS
|
|
loopnez a12, .Loop1done
|
|
#else
|
|
beqz a12, .Loop1done
|
|
slli a12, a12, 2
|
|
add a12, a12, a11 # a12 = end of last 4B chunck
|
|
#endif
|
|
.Loop1:
|
|
EX(l32i, a9, a3, 0, fixup_l) # get word from src
|
|
addi a3, a3, 4 # advance src pointer
|
|
bnone a9, a5, .Lz0 # if byte 0 is zero
|
|
bnone a9, a6, .Lz1 # if byte 1 is zero
|
|
bnone a9, a7, .Lz2 # if byte 2 is zero
|
|
EX(s32i, a9, a11, 0, fixup_s) # store word to dst
|
|
bnone a9, a8, .Lz3 # if byte 3 is zero
|
|
addi a11, a11, 4 # advance dst pointer
|
|
#if !XCHAL_HAVE_LOOPS
|
|
blt a11, a12, .Loop1
|
|
#endif
|
|
|
|
.Loop1done:
|
|
bbci.l a4, 1, .L100
|
|
# copy 2 bytes
|
|
EX(l16ui, a9, a3, 0, fixup_l)
|
|
addi a3, a3, 2 # advance src pointer
|
|
#ifdef __XTENSA_EB__
|
|
bnone a9, a7, .Lz0 # if byte 2 is zero
|
|
bnone a9, a8, .Lz1 # if byte 3 is zero
|
|
#else
|
|
bnone a9, a5, .Lz0 # if byte 0 is zero
|
|
bnone a9, a6, .Lz1 # if byte 1 is zero
|
|
#endif
|
|
EX(s16i, a9, a11, 0, fixup_s)
|
|
addi a11, a11, 2 # advance dst pointer
|
|
.L100:
|
|
bbci.l a4, 0, .Lret
|
|
EX(l8ui, a9, a3, 0, fixup_l)
|
|
/* slot */
|
|
EX(s8i, a9, a11, 0, fixup_s)
|
|
beqz a9, .Lret # if byte is zero
|
|
addi a11, a11, 1-3 # advance dst ptr 1, but also cancel
|
|
# the effect of adding 3 in .Lz3 code
|
|
/* fall thru to .Lz3 and "retw" */
|
|
|
|
.Lz3: # byte 3 is zero
|
|
addi a11, a11, 3 # advance dst pointer
|
|
sub a2, a11, a2 # compute strlen
|
|
retw
|
|
.Lz0: # byte 0 is zero
|
|
#ifdef __XTENSA_EB__
|
|
movi a9, 0
|
|
#endif /* __XTENSA_EB__ */
|
|
EX(s8i, a9, a11, 0, fixup_s)
|
|
sub a2, a11, a2 # compute strlen
|
|
retw
|
|
.Lz1: # byte 1 is zero
|
|
#ifdef __XTENSA_EB__
|
|
extui a9, a9, 16, 16
|
|
#endif /* __XTENSA_EB__ */
|
|
EX(s16i, a9, a11, 0, fixup_s)
|
|
addi a11, a11, 1 # advance dst pointer
|
|
sub a2, a11, a2 # compute strlen
|
|
retw
|
|
.Lz2: # byte 2 is zero
|
|
#ifdef __XTENSA_EB__
|
|
extui a9, a9, 16, 16
|
|
#endif /* __XTENSA_EB__ */
|
|
EX(s16i, a9, a11, 0, fixup_s)
|
|
movi a9, 0
|
|
EX(s8i, a9, a11, 2, fixup_s)
|
|
addi a11, a11, 2 # advance dst pointer
|
|
sub a2, a11, a2 # compute strlen
|
|
retw
|
|
|
|
.align 4 # 1 mod 4 alignment for LOOPNEZ
|
|
.byte 0 # (0 mod 4 alignment for LBEG)
|
|
.Ldstunaligned:
|
|
/*
|
|
* for now just use byte copy loop
|
|
*/
|
|
#if XCHAL_HAVE_LOOPS
|
|
loopnez a4, .Lunalignedend
|
|
#else
|
|
beqz a4, .Lunalignedend
|
|
add a12, a11, a4 # a12 = ending address
|
|
#endif /* XCHAL_HAVE_LOOPS */
|
|
.Lnextbyte:
|
|
EX(l8ui, a9, a3, 0, fixup_l)
|
|
addi a3, a3, 1
|
|
EX(s8i, a9, a11, 0, fixup_s)
|
|
beqz a9, .Lunalignedend
|
|
addi a11, a11, 1
|
|
#if !XCHAL_HAVE_LOOPS
|
|
blt a11, a12, .Lnextbyte
|
|
#endif
|
|
|
|
.Lunalignedend:
|
|
sub a2, a11, a2 # compute strlen
|
|
retw
|
|
|
|
|
|
.section .fixup, "ax"
|
|
.align 4
|
|
|
|
/* For now, just return -EFAULT. Future implementations might
|
|
* like to clear remaining kernel space, like the fixup
|
|
* implementation in memset(). Thus, we differentiate between
|
|
* load/store fixups. */
|
|
|
|
fixup_s:
|
|
fixup_l:
|
|
movi a2, -EFAULT
|
|
retw
|
|
|