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/* SPDX-License-Identifier: GPL-2.0 */
/*
* Copyright (C) 2020-2022 Loongson Technology Corporation Limited
*/
#include <linux/export.h>
#include <asm/alternative-asm.h>
#include <asm/asm.h>
#include <asm/asmmacro.h>
#include <asm/asm-extable.h>
#include <asm/cpu.h>
#include <asm/regdef.h>
#include <asm/unwind_hints.h>
SYM_FUNC_START(__clear_user)
/*
* Some CPUs support hardware unaligned access
*/
ALTERNATIVE "b __clear_user_generic", \
"b __clear_user_fast", CPU_FEATURE_UAL
SYM_FUNC_END(__clear_user)
EXPORT_SYMBOL(__clear_user)
/*
* unsigned long __clear_user_generic(void *addr, size_t size)
*
* a0: addr
* a1: size
*/
SYM_FUNC_START(__clear_user_generic)
beqz a1, 2f
1: st.b zero, a0, 0
addi.d a0, a0, 1
addi.d a1, a1, -1
bgtz a1, 1b
2: move a0, a1
jr ra
_asm_extable 1b, 2b
SYM_FUNC_END(__clear_user_generic)
/*
* unsigned long __clear_user_fast(void *addr, unsigned long size)
*
* a0: addr
* a1: size
*/
SYM_FUNC_START(__clear_user_fast)
sltui t0, a1, 9
bnez t0, .Lsmall
add.d a2, a0, a1
0: st.d zero, a0, 0
/* align up address */
addi.d a0, a0, 8
bstrins.d a0, zero, 2, 0
addi.d a3, a2, -64
bgeu a0, a3, .Llt64
/* set 64 bytes at a time */
.Lloop64:
1: st.d zero, a0, 0
2: st.d zero, a0, 8
3: st.d zero, a0, 16
4: st.d zero, a0, 24
5: st.d zero, a0, 32
6: st.d zero, a0, 40
7: st.d zero, a0, 48
8: st.d zero, a0, 56
addi.d a0, a0, 64
bltu a0, a3, .Lloop64
/* set the remaining bytes */
.Llt64:
addi.d a3, a2, -32
bgeu a0, a3, .Llt32
9: st.d zero, a0, 0
10: st.d zero, a0, 8
11: st.d zero, a0, 16
12: st.d zero, a0, 24
addi.d a0, a0, 32
.Llt32:
addi.d a3, a2, -16
bgeu a0, a3, .Llt16
13: st.d zero, a0, 0
14: st.d zero, a0, 8
addi.d a0, a0, 16
.Llt16:
addi.d a3, a2, -8
bgeu a0, a3, .Llt8
15: st.d zero, a0, 0
addi.d a0, a0, 8
.Llt8:
16: st.d zero, a2, -8
/* return */
move a0, zero
jr ra
.align 4
.Lsmall:
pcaddi t0, 4
slli.d a2, a1, 4
add.d t0, t0, a2
jr t0
.align 4
move a0, zero
jr ra
.align 4
17: st.b zero, a0, 0
move a0, zero
jr ra
.align 4
18: st.h zero, a0, 0
move a0, zero
jr ra
.align 4
19: st.h zero, a0, 0
20: st.b zero, a0, 2
move a0, zero
jr ra
.align 4
21: st.w zero, a0, 0
move a0, zero
jr ra
.align 4
22: st.w zero, a0, 0
23: st.b zero, a0, 4
move a0, zero
jr ra
.align 4
24: st.w zero, a0, 0
25: st.h zero, a0, 4
move a0, zero
jr ra
.align 4
26: st.w zero, a0, 0
27: st.w zero, a0, 3
move a0, zero
jr ra
.align 4
28: st.d zero, a0, 0
move a0, zero
jr ra
/* fixup and ex_table */
.Llarge_fixup:
sub.d a1, a2, a0
.Lsmall_fixup:
29: st.b zero, a0, 0
addi.d a0, a0, 1
addi.d a1, a1, -1
bgt a1, zero, 29b
.Lexit:
move a0, a1
jr ra
_asm_extable 0b, .Lsmall_fixup
_asm_extable 1b, .Llarge_fixup
_asm_extable 2b, .Llarge_fixup
_asm_extable 3b, .Llarge_fixup
_asm_extable 4b, .Llarge_fixup
_asm_extable 5b, .Llarge_fixup
_asm_extable 6b, .Llarge_fixup
_asm_extable 7b, .Llarge_fixup
_asm_extable 8b, .Llarge_fixup
_asm_extable 9b, .Llarge_fixup
_asm_extable 10b, .Llarge_fixup
_asm_extable 11b, .Llarge_fixup
_asm_extable 12b, .Llarge_fixup
_asm_extable 13b, .Llarge_fixup
_asm_extable 14b, .Llarge_fixup
_asm_extable 15b, .Llarge_fixup
_asm_extable 16b, .Llarge_fixup
_asm_extable 17b, .Lexit
_asm_extable 18b, .Lsmall_fixup
_asm_extable 19b, .Lsmall_fixup
_asm_extable 20b, .Lsmall_fixup
_asm_extable 21b, .Lsmall_fixup
_asm_extable 22b, .Lsmall_fixup
_asm_extable 23b, .Lsmall_fixup
_asm_extable 24b, .Lsmall_fixup
_asm_extable 25b, .Lsmall_fixup
_asm_extable 26b, .Lsmall_fixup
_asm_extable 27b, .Lsmall_fixup
_asm_extable 28b, .Lsmall_fixup
_asm_extable 29b, .Lexit
SYM_FUNC_END(__clear_user_fast)
STACK_FRAME_NON_STANDARD __clear_user_fast
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