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0f61f6be1f
Now that we have SYM_FUNC_ALIAS() and SYM_FUNC_ALIAS_WEAK(), use those
to simplify and more consistently define function aliases across
arch/arm64.
Aliases are now defined in terms of a canonical function name. For
position-independent functions I've made the __pi_<func> name the
canonical name, and defined other alises in terms of this.
The SYM_FUNC_{START,END}_PI(func) macros obscure the __pi_<func> name,
and make this hard to seatch for. The SYM_FUNC_START_WEAK_PI() macro
also obscures the fact that the __pi_<func> fymbol is global and the
<func> symbol is weak. For clarity, I have removed these macros and used
SYM_FUNC_{START,END}() directly with the __pi_<func> name.
For example:
SYM_FUNC_START_WEAK_PI(func)
... asm insns ...
SYM_FUNC_END_PI(func)
EXPORT_SYMBOL(func)
... becomes:
SYM_FUNC_START(__pi_func)
... asm insns ...
SYM_FUNC_END(__pi_func)
SYM_FUNC_ALIAS_WEAK(func, __pi_func)
EXPORT_SYMBOL(func)
For clarity, where there are multiple annotations such as
EXPORT_SYMBOL(), I've tried to keep annotations grouped by symbol. For
example, where a function has a name and an alias which are both
exported, this is organised as:
SYM_FUNC_START(func)
... asm insns ...
SYM_FUNC_END(func)
EXPORT_SYMBOL(func)
SYM_FUNC_ALIAS(alias, func)
EXPORT_SYMBOL(alias)
For consistency with the other string functions, I've defined strrchr as
a position-independent function, as it can safely be used as such even
though we have no users today.
As we no longer use SYM_FUNC_{START,END}_ALIAS(), our local copies are
removed. The common versions will be removed by a subsequent patch.
There should be no functional change as a result of this patch.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Mark Brown <broonie@kernel.org>
Cc: Joey Gouly <joey.gouly@arm.com>
Cc: Will Deacon <will@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20220216162229.1076788-3-mark.rutland@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
77 lines
1.4 KiB
ArmAsm
77 lines
1.4 KiB
ArmAsm
/* SPDX-License-Identifier: GPL-2.0-only */
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/*
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* Copyright (C) 2021 Arm Ltd.
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*/
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#include <linux/linkage.h>
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#include <asm/assembler.h>
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/*
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* Find a character in an area of memory.
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*
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* Parameters:
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* x0 - buf
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* x1 - c
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* x2 - n
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* Returns:
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* x0 - address of first occurrence of 'c' or 0
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*/
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#define L(label) .L ## label
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#define REP8_01 0x0101010101010101
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#define REP8_7f 0x7f7f7f7f7f7f7f7f
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#define srcin x0
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#define chrin w1
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#define cntin x2
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#define result x0
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#define wordcnt x3
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#define rep01 x4
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#define repchr x5
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#define cur_word x6
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#define cur_byte w6
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#define tmp x7
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#define tmp2 x8
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.p2align 4
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nop
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SYM_FUNC_START(__pi_memchr)
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and chrin, chrin, #0xff
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lsr wordcnt, cntin, #3
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cbz wordcnt, L(byte_loop)
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mov rep01, #REP8_01
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mul repchr, x1, rep01
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and cntin, cntin, #7
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L(word_loop):
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ldr cur_word, [srcin], #8
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sub wordcnt, wordcnt, #1
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eor cur_word, cur_word, repchr
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sub tmp, cur_word, rep01
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orr tmp2, cur_word, #REP8_7f
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bics tmp, tmp, tmp2
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b.ne L(found_word)
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cbnz wordcnt, L(word_loop)
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L(byte_loop):
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cbz cntin, L(not_found)
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ldrb cur_byte, [srcin], #1
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sub cntin, cntin, #1
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cmp cur_byte, chrin
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b.ne L(byte_loop)
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sub srcin, srcin, #1
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ret
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L(found_word):
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CPU_LE( rev tmp, tmp)
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clz tmp, tmp
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sub tmp, tmp, #64
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add result, srcin, tmp, asr #3
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ret
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L(not_found):
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mov result, #0
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ret
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SYM_FUNC_END(__pi_memchr)
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SYM_FUNC_ALIAS_WEAK(memchr, __pi_memchr)
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EXPORT_SYMBOL_NOKASAN(memchr)
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