diff options
Diffstat (limited to 'arch/loongarch/lib/clear_user.S')
| -rw-r--r-- | arch/loongarch/lib/clear_user.S | 206 |
1 files changed, 206 insertions, 0 deletions
diff --git a/arch/loongarch/lib/clear_user.S b/arch/loongarch/lib/clear_user.S new file mode 100644 index 0000000000..be741544e6 --- /dev/null +++ b/arch/loongarch/lib/clear_user.S @@ -0,0 +1,206 @@ +/* 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> + +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) |