linux-zen-desktop/arch/loongarch/lib/clear_user.S

99 lines
1.9 KiB
ArmAsm

/* SPDX-License-Identifier: GPL-2.0 */
/*
* Copyright (C) 2020-2022 Loongson Technology Corporation Limited
*/
#include <asm/alternative-asm.h>
#include <asm/asm.h>
#include <asm/asmmacro.h>
#include <asm/asm-extable.h>
#include <asm/cpu.h>
#include <asm/export.h>
#include <asm/regdef.h>
.irp to, 0, 1, 2, 3, 4, 5, 6, 7
.L_fixup_handle_\to\():
addi.d a0, a1, (\to) * (-8)
jr ra
.endr
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, .L_fixup_handle_0
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)
beqz a1, 10f
ori a2, zero, 64
blt a1, a2, 9f
/* set 64 bytes at a time */
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
addi.d a1, a1, -64
bge a1, a2, 1b
beqz a1, 10f
/* set the remaining bytes */
9: st.b zero, a0, 0
addi.d a0, a0, 1
addi.d a1, a1, -1
bgt a1, zero, 9b
/* return */
10: move a0, a1
jr ra
/* fixup and ex_table */
_asm_extable 1b, .L_fixup_handle_0
_asm_extable 2b, .L_fixup_handle_1
_asm_extable 3b, .L_fixup_handle_2
_asm_extable 4b, .L_fixup_handle_3
_asm_extable 5b, .L_fixup_handle_4
_asm_extable 6b, .L_fixup_handle_5
_asm_extable 7b, .L_fixup_handle_6
_asm_extable 8b, .L_fixup_handle_7
_asm_extable 9b, .L_fixup_handle_0
SYM_FUNC_END(__clear_user_fast)