diff options
Diffstat (limited to 'arch/loongarch/lib/clear_user.S')
| -rw-r--r-- | arch/loongarch/lib/clear_user.S | 98 |
1 files changed, 98 insertions, 0 deletions
diff --git a/arch/loongarch/lib/clear_user.S b/arch/loongarch/lib/clear_user.S new file mode 100644 index 000000000..2dc48e61a --- /dev/null +++ b/arch/loongarch/lib/clear_user.S @@ -0,0 +1,98 @@ +/* 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) |