diff options
Diffstat (limited to 'arch/s390/lib/mem.S')
| -rw-r--r-- | arch/s390/lib/mem.S | 191 |
1 files changed, 191 insertions, 0 deletions
diff --git a/arch/s390/lib/mem.S b/arch/s390/lib/mem.S new file mode 100644 index 000000000..dc0874f2e --- /dev/null +++ b/arch/s390/lib/mem.S @@ -0,0 +1,191 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * String handling functions. + * + * Copyright IBM Corp. 2012 + */ + +#include <linux/linkage.h> +#include <asm/export.h> +#include <asm/nospec-insn.h> + + GEN_BR_THUNK %r14 + +/* + * void *memmove(void *dest, const void *src, size_t n) + */ +WEAK(memmove) +ENTRY(__memmove) + ltgr %r4,%r4 + lgr %r1,%r2 + jz .Lmemmove_exit + aghi %r4,-1 + clgr %r2,%r3 + jnh .Lmemmove_forward + la %r5,1(%r4,%r3) + clgr %r2,%r5 + jl .Lmemmove_reverse +.Lmemmove_forward: + srlg %r0,%r4,8 + ltgr %r0,%r0 + jz .Lmemmove_forward_remainder +.Lmemmove_forward_loop: + mvc 0(256,%r1),0(%r3) + la %r1,256(%r1) + la %r3,256(%r3) + brctg %r0,.Lmemmove_forward_loop +.Lmemmove_forward_remainder: + larl %r5,.Lmemmove_mvc + ex %r4,0(%r5) +.Lmemmove_exit: + BR_EX %r14 +.Lmemmove_reverse: + ic %r0,0(%r4,%r3) + stc %r0,0(%r4,%r1) + brctg %r4,.Lmemmove_reverse + ic %r0,0(%r4,%r3) + stc %r0,0(%r4,%r1) + BR_EX %r14 +.Lmemmove_mvc: + mvc 0(1,%r1),0(%r3) +ENDPROC(__memmove) +EXPORT_SYMBOL(memmove) + +/* + * memset implementation + * + * This code corresponds to the C construct below. We do distinguish + * between clearing (c == 0) and setting a memory array (c != 0) simply + * because nearly all memset invocations in the kernel clear memory and + * the xc instruction is preferred in such cases. + * + * void *memset(void *s, int c, size_t n) + * { + * if (likely(c == 0)) + * return __builtin_memset(s, 0, n); + * return __builtin_memset(s, c, n); + * } + */ +WEAK(memset) +ENTRY(__memset) + ltgr %r4,%r4 + jz .Lmemset_exit + ltgr %r3,%r3 + jnz .Lmemset_fill + aghi %r4,-1 + srlg %r3,%r4,8 + ltgr %r3,%r3 + lgr %r1,%r2 + jz .Lmemset_clear_remainder +.Lmemset_clear_loop: + xc 0(256,%r1),0(%r1) + la %r1,256(%r1) + brctg %r3,.Lmemset_clear_loop +.Lmemset_clear_remainder: + larl %r3,.Lmemset_xc + ex %r4,0(%r3) +.Lmemset_exit: + BR_EX %r14 +.Lmemset_fill: + cghi %r4,1 + lgr %r1,%r2 + je .Lmemset_fill_exit + aghi %r4,-2 + srlg %r5,%r4,8 + ltgr %r5,%r5 + jz .Lmemset_fill_remainder +.Lmemset_fill_loop: + stc %r3,0(%r1) + mvc 1(255,%r1),0(%r1) + la %r1,256(%r1) + brctg %r5,.Lmemset_fill_loop +.Lmemset_fill_remainder: + stc %r3,0(%r1) + larl %r5,.Lmemset_mvc + ex %r4,0(%r5) + BR_EX %r14 +.Lmemset_fill_exit: + stc %r3,0(%r1) + BR_EX %r14 +.Lmemset_xc: + xc 0(1,%r1),0(%r1) +.Lmemset_mvc: + mvc 1(1,%r1),0(%r1) +ENDPROC(__memset) +EXPORT_SYMBOL(memset) + +/* + * memcpy implementation + * + * void *memcpy(void *dest, const void *src, size_t n) + */ +WEAK(memcpy) +ENTRY(__memcpy) + ltgr %r4,%r4 + jz .Lmemcpy_exit + aghi %r4,-1 + srlg %r5,%r4,8 + ltgr %r5,%r5 + lgr %r1,%r2 + jnz .Lmemcpy_loop +.Lmemcpy_remainder: + larl %r5,.Lmemcpy_mvc + ex %r4,0(%r5) +.Lmemcpy_exit: + BR_EX %r14 +.Lmemcpy_loop: + mvc 0(256,%r1),0(%r3) + la %r1,256(%r1) + la %r3,256(%r3) + brctg %r5,.Lmemcpy_loop + j .Lmemcpy_remainder +.Lmemcpy_mvc: + mvc 0(1,%r1),0(%r3) +ENDPROC(__memcpy) +EXPORT_SYMBOL(memcpy) + +/* + * __memset16/32/64 + * + * void *__memset16(uint16_t *s, uint16_t v, size_t count) + * void *__memset32(uint32_t *s, uint32_t v, size_t count) + * void *__memset64(uint64_t *s, uint64_t v, size_t count) + */ +.macro __MEMSET bits,bytes,insn +ENTRY(__memset\bits) + ltgr %r4,%r4 + jz .L__memset_exit\bits + cghi %r4,\bytes + je .L__memset_store\bits + aghi %r4,-(\bytes+1) + srlg %r5,%r4,8 + ltgr %r5,%r5 + lgr %r1,%r2 + jz .L__memset_remainder\bits +.L__memset_loop\bits: + \insn %r3,0(%r1) + mvc \bytes(256-\bytes,%r1),0(%r1) + la %r1,256(%r1) + brctg %r5,.L__memset_loop\bits +.L__memset_remainder\bits: + \insn %r3,0(%r1) + larl %r5,.L__memset_mvc\bits + ex %r4,0(%r5) + BR_EX %r14 +.L__memset_store\bits: + \insn %r3,0(%r2) +.L__memset_exit\bits: + BR_EX %r14 +.L__memset_mvc\bits: + mvc \bytes(1,%r1),0(%r1) +ENDPROC(__memset\bits) +.endm + +__MEMSET 16,2,sth +EXPORT_SYMBOL(__memset16) + +__MEMSET 32,4,st +EXPORT_SYMBOL(__memset32) + +__MEMSET 64,8,stg +EXPORT_SYMBOL(__memset64) |