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OpenCloudOS-Kernel/arch/arm64/lib/strrchr.S

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arm64: klib: Optimised string functions This patch introduces AArch64-specific string functions (strchr, strrchr). Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2013-03-22 00:23:43 +08:00
/*
* Based on arch/arm/lib/strrchr.S
*
* Copyright (C) 1995-2000 Russell King
* Copyright (C) 2013 ARM Ltd.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <linux/linkage.h>
#include <asm/assembler.h>
/*
* Find the last occurrence of a character in a string.
*
* Parameters:
* x0 - str
* x1 - c
* Returns:
* x0 - address of last occurrence of 'c' or 0
*/
arm64: lib: use C string functions with KASAN enabled ARM64 has asm implementation of memchr(), memcmp(), str[r]chr(), str[n]cmp(), str[n]len(). KASAN don't see memory accesses in asm code, thus it can potentially miss many bugs. Ifdef out __HAVE_ARCH_* defines of these functions when KASAN is enabled, so the generic implementations from lib/string.c will be used. We can't just remove the asm functions because efistub uses them. And we can't have two non-weak functions either, so declare the asm functions as weak. Link: http://lkml.kernel.org/r/20180920135631.23833-2-aryabinin@virtuozzo.com Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Reported-by: Kyeongdon Kim <kyeongdon.kim@lge.com> Cc: Alexander Potapenko <glider@google.com> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-10-27 06:02:30 +08:00
WEAK(strrchr)
arm64: klib: Optimised string functions This patch introduces AArch64-specific string functions (strchr, strrchr). Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2013-03-22 00:23:43 +08:00
mov x3, #0
and w1, w1, #0xff
1: ldrb w2, [x0], #1
cbz w2, 2f
cmp w2, w1
b.ne 1b
sub x3, x0, #1
b 1b
2: mov x0, x3
ret
arm64/efi: Make strrchr() available to the EFI namespace libfdt gained a new dependency on strrchr, so make it available to the EFI namespace before we update libfdt. Thanks to Ard for providing this fix. Cc: Catalin Marinas <catalin.marinas@arm.com> Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Acked-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Rob Herring <robh@kernel.org>
2018-03-02 00:12:07 +08:00
ENDPIPROC(strrchr)
arm64: string: use asm EXPORT_SYMBOL() For a while now it's been possible to use EXPORT_SYMBOL() in assembly files, which allows us to place exports immediately after assembly functions, as we do for C functions. As a step towards removing arm64ksyms.c, let's move the string routine exports to the assembly files the functions are defined in. Routines which should only be exported for !KASAN builds are exported using the EXPORT_SYMBOL_NOKASAN() helper. There should be no functional change as a result of this patch. Signed-off-by: Mark Rutland <mark.rutland@arm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Will Deacon <will.deacon@arm.com>
2018-12-08 02:08:21 +08:00
EXPORT_SYMBOL_NOKASAN(strrchr)