[PATCH] ARM: Change arch/arm/lib/mem*.S to use WEAK instead of .weak

From: Fangrui Song <maskray@google.com>
To: Linus Walleij <linus.walleij@linaro.org>
Cc: Florian Fainelli <f.fainelli@gmail.com>,
	Fangrui Song <maskray@google.com>, Arnd Bergmann <arnd@arndb.de>,
	Abbott Liu <liuwenliang@huawei.com>,
	Nick Desaulniers <ndesaulniers@google.com>,
	Russell King <linux@armlinux.org.uk>,
	Mike Rapoport <rppt@linux.ibm.com>,
	clang-built-linux@googlegroups.com,
	Andrey Ryabinin <aryabinin@virtuozzo.com>,
	Ard Biesheuvel <ardb@kernel.org>,
	linux-arm-kernel@lists.infradead.org
Subject: [PATCH] ARM: Change arch/arm/lib/mem*.S to use WEAK instead of .weak
Date: Thu,  5 Nov 2020 10:15:42 -0800	[thread overview]
Message-ID: <20201105181542.854788-1-maskray@google.com> (raw)

Commit d6d51a96c7d6 ("ARM: 9014/2: Replace string mem* functions for
KASan") add .weak directives to memcpy/memmove/memset to avoid collision
with KASAN interceptors.

This does not work with LLVM's integrated assembler (the assembly snippet
`.weak memcpy ... .globl memcpy` produces a STB_GLOBAL memcpy while GNU as
produces a STB_WEAK memcpy). LLVM 12 (since https://reviews.llvm.org/D90108)
will error on such an overridden symbol binding.

Use the appropriate WEAK macro instead.

Fixes: d6d51a96c7d6 ("ARM: 9014/2: Replace string mem* functions for KASan")
Reported-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Fangrui Song <maskray@google.com>
Link: https://github.com/ClangBuiltLinux/linux/issues/1190
---
 arch/arm/lib/memcpy.S  | 3 +--
 arch/arm/lib/memmove.S | 3 +--
 arch/arm/lib/memset.S  | 3 +--
 3 files changed, 3 insertions(+), 6 deletions(-)

diff --git a/arch/arm/lib/memcpy.S b/arch/arm/lib/memcpy.S
index ad4625d16e11..e4caf48c089f 100644
--- a/arch/arm/lib/memcpy.S
+++ b/arch/arm/lib/memcpy.S
@@ -58,10 +58,9 @@
 
 /* Prototype: void *memcpy(void *dest, const void *src, size_t n); */
 
-.weak memcpy
 ENTRY(__memcpy)
 ENTRY(mmiocpy)
-ENTRY(memcpy)
+WEAK(memcpy)
 
 #include "copy_template.S"
 
diff --git a/arch/arm/lib/memmove.S b/arch/arm/lib/memmove.S
index fd123ea5a5a4..6fecc12a1f51 100644
--- a/arch/arm/lib/memmove.S
+++ b/arch/arm/lib/memmove.S
@@ -24,9 +24,8 @@
  * occurring in the opposite direction.
  */
 
-.weak memmove
 ENTRY(__memmove)
-ENTRY(memmove)
+WEAK(memmove)
 	UNWIND(	.fnstart			)
 
 		subs	ip, r0, r1
diff --git a/arch/arm/lib/memset.S b/arch/arm/lib/memset.S
index 0e7ff0423f50..9817cb258c1a 100644
--- a/arch/arm/lib/memset.S
+++ b/arch/arm/lib/memset.S
@@ -13,10 +13,9 @@
 	.text
 	.align	5
 
-.weak memset
 ENTRY(__memset)
 ENTRY(mmioset)
-ENTRY(memset)
+WEAK(memset)
 UNWIND( .fnstart         )
 	ands	r3, r0, #3		@ 1 unaligned?
 	mov	ip, r0			@ preserve r0 as return value
-- 
2.29.1.341.ge80a0c044ae-goog


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