linux-stable/arch/arm64/lib/strchr.S

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/* SPDX-License-Identifier: GPL-2.0-only */
/*
* Based on arch/arm/lib/strchr.S
*
* Copyright (C) 1995-2000 Russell King
* Copyright (C) 2013 ARM Ltd.
*/
#include <linux/linkage.h>
#include <asm/assembler.h>
/*
* Find the first occurrence of a character in a string.
*
* Parameters:
* x0 - str
* x1 - c
* Returns:
* x0 - address of first occurrence of 'c' or 0
*/
arm64: clean up symbol aliasing 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>
2022-02-16 16:22:27 +00:00
SYM_FUNC_START(__pi_strchr)
and w1, w1, #0xff
1: ldrb w2, [x0], #1
cmp w2, w1
ccmp w2, wzr, #4, ne
b.ne 1b
sub x0, x0, #1
cmp w2, w1
csel x0, x0, xzr, eq
ret
arm64: clean up symbol aliasing 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>
2022-02-16 16:22:27 +00:00
SYM_FUNC_END(__pi_strchr)
SYM_FUNC_ALIAS_WEAK(strchr, __pi_strchr)
EXPORT_SYMBOL_NOKASAN(strchr)