5eda25b102
The memove, memset, memcpy, __memset16, __memset32 and __memset64
function have an additional indirect return branch in form of a
"bzr" instruction. These need to use expolines as well.
Cc: <stable@vger.kernel.org> # v4.17+
Fixes: 97489e0663 ("s390/lib: use expoline for indirect branches")
Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
184 lines
3.5 KiB
ArmAsm
184 lines
3.5 KiB
ArmAsm
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* String handling functions.
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*
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* Copyright IBM Corp. 2012
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*/
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#include <linux/linkage.h>
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#include <asm/export.h>
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#include <asm/nospec-insn.h>
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GEN_BR_THUNK %r14
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/*
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* void *memmove(void *dest, const void *src, size_t n)
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*/
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ENTRY(memmove)
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ltgr %r4,%r4
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lgr %r1,%r2
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jz .Lmemmove_exit
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aghi %r4,-1
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clgr %r2,%r3
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jnh .Lmemmove_forward
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la %r5,1(%r4,%r3)
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clgr %r2,%r5
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jl .Lmemmove_reverse
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.Lmemmove_forward:
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srlg %r0,%r4,8
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ltgr %r0,%r0
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jz .Lmemmove_forward_remainder
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.Lmemmove_forward_loop:
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mvc 0(256,%r1),0(%r3)
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la %r1,256(%r1)
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la %r3,256(%r3)
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brctg %r0,.Lmemmove_forward_loop
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.Lmemmove_forward_remainder:
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larl %r5,.Lmemmove_mvc
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ex %r4,0(%r5)
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.Lmemmove_exit:
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BR_EX %r14
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.Lmemmove_reverse:
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ic %r0,0(%r4,%r3)
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stc %r0,0(%r4,%r1)
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brctg %r4,.Lmemmove_reverse
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ic %r0,0(%r4,%r3)
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stc %r0,0(%r4,%r1)
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BR_EX %r14
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.Lmemmove_mvc:
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mvc 0(1,%r1),0(%r3)
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EXPORT_SYMBOL(memmove)
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/*
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* memset implementation
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*
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* This code corresponds to the C construct below. We do distinguish
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* between clearing (c == 0) and setting a memory array (c != 0) simply
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* because nearly all memset invocations in the kernel clear memory and
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* the xc instruction is preferred in such cases.
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*
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* void *memset(void *s, int c, size_t n)
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* {
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* if (likely(c == 0))
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* return __builtin_memset(s, 0, n);
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* return __builtin_memset(s, c, n);
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* }
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*/
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ENTRY(memset)
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ltgr %r4,%r4
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jz .Lmemset_exit
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ltgr %r3,%r3
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jnz .Lmemset_fill
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aghi %r4,-1
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srlg %r3,%r4,8
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ltgr %r3,%r3
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lgr %r1,%r2
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jz .Lmemset_clear_remainder
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.Lmemset_clear_loop:
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xc 0(256,%r1),0(%r1)
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la %r1,256(%r1)
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brctg %r3,.Lmemset_clear_loop
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.Lmemset_clear_remainder:
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larl %r3,.Lmemset_xc
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ex %r4,0(%r3)
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.Lmemset_exit:
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BR_EX %r14
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.Lmemset_fill:
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cghi %r4,1
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lgr %r1,%r2
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je .Lmemset_fill_exit
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aghi %r4,-2
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srlg %r5,%r4,8
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ltgr %r5,%r5
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jz .Lmemset_fill_remainder
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.Lmemset_fill_loop:
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stc %r3,0(%r1)
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mvc 1(255,%r1),0(%r1)
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la %r1,256(%r1)
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brctg %r5,.Lmemset_fill_loop
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.Lmemset_fill_remainder:
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stc %r3,0(%r1)
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larl %r5,.Lmemset_mvc
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ex %r4,0(%r5)
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BR_EX %r14
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.Lmemset_fill_exit:
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stc %r3,0(%r1)
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BR_EX %r14
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.Lmemset_xc:
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xc 0(1,%r1),0(%r1)
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.Lmemset_mvc:
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mvc 1(1,%r1),0(%r1)
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EXPORT_SYMBOL(memset)
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/*
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* memcpy implementation
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*
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* void *memcpy(void *dest, const void *src, size_t n)
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*/
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ENTRY(memcpy)
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ltgr %r4,%r4
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jz .Lmemcpy_exit
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aghi %r4,-1
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srlg %r5,%r4,8
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ltgr %r5,%r5
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lgr %r1,%r2
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jnz .Lmemcpy_loop
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.Lmemcpy_remainder:
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larl %r5,.Lmemcpy_mvc
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ex %r4,0(%r5)
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.Lmemcpy_exit:
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BR_EX %r14
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.Lmemcpy_loop:
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mvc 0(256,%r1),0(%r3)
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la %r1,256(%r1)
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la %r3,256(%r3)
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brctg %r5,.Lmemcpy_loop
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j .Lmemcpy_remainder
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.Lmemcpy_mvc:
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mvc 0(1,%r1),0(%r3)
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EXPORT_SYMBOL(memcpy)
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/*
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* __memset16/32/64
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*
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* void *__memset16(uint16_t *s, uint16_t v, size_t count)
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* void *__memset32(uint32_t *s, uint32_t v, size_t count)
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* void *__memset64(uint64_t *s, uint64_t v, size_t count)
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*/
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.macro __MEMSET bits,bytes,insn
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ENTRY(__memset\bits)
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ltgr %r4,%r4
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jz .L__memset_exit\bits
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cghi %r4,\bytes
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je .L__memset_store\bits
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aghi %r4,-(\bytes+1)
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srlg %r5,%r4,8
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ltgr %r5,%r5
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lgr %r1,%r2
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jz .L__memset_remainder\bits
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.L__memset_loop\bits:
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\insn %r3,0(%r1)
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mvc \bytes(256-\bytes,%r1),0(%r1)
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la %r1,256(%r1)
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brctg %r5,.L__memset_loop\bits
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.L__memset_remainder\bits:
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\insn %r3,0(%r1)
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larl %r5,.L__memset_mvc\bits
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ex %r4,0(%r5)
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BR_EX %r14
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.L__memset_store\bits:
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\insn %r3,0(%r2)
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.L__memset_exit\bits:
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BR_EX %r14
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.L__memset_mvc\bits:
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mvc \bytes(1,%r1),0(%r1)
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.endm
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__MEMSET 16,2,sth
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EXPORT_SYMBOL(__memset16)
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__MEMSET 32,4,st
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EXPORT_SYMBOL(__memset32)
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__MEMSET 64,8,stg
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EXPORT_SYMBOL(__memset64)
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