From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Sasha Levin <sashal@kernel.org>,
Szabolcs Nagy <szabolcs.nagy@arm.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Vincenzo Frascino <vincenzo.frascino@arm.com>,
Will Deacon <will@kernel.org>,
linux-arm-kernel@lists.infradead.org
Subject: [PATCH AUTOSEL 5.4 33/35] arm64: vdso: Add -fasynchronous-unwind-tables to cflags
Date: Thu, 7 May 2020 10:28:27 -0400 [thread overview]
Message-ID: <20200507142830.26239-33-sashal@kernel.org> (raw)
In-Reply-To: <20200507142830.26239-1-sashal@kernel.org>
From: Vincenzo Frascino <vincenzo.frascino@arm.com>
[ Upstream commit 1578e5d03112e3e9d37e1c4d95b6dfb734c73955 ]
On arm64 linux gcc uses -fasynchronous-unwind-tables -funwind-tables
by default since gcc-8, so now the de facto platform ABI is to allow
unwinding from async signal handlers.
However on bare metal targets (aarch64-none-elf), and on old gcc,
async and sync unwind tables are not enabled by default to avoid
runtime memory costs.
This means if linux is built with a baremetal toolchain the vdso.so
may not have unwind tables which breaks the gcc platform ABI guarantee
in userspace.
Add -fasynchronous-unwind-tables explicitly to the vgettimeofday.o
cflags to address the ABI change.
Fixes: 28b1a824a4f4 ("arm64: vdso: Substitute gettimeofday() with C implementation")
Cc: Will Deacon <will@kernel.org>
Reported-by: Szabolcs Nagy <szabolcs.nagy@arm.com>
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/arm64/kernel/vdso/Makefile | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/arm64/kernel/vdso/Makefile b/arch/arm64/kernel/vdso/Makefile
index dd2514bb1511f..3862cad2410cf 100644
--- a/arch/arm64/kernel/vdso/Makefile
+++ b/arch/arm64/kernel/vdso/Makefile
@@ -32,7 +32,7 @@ UBSAN_SANITIZE := n
OBJECT_FILES_NON_STANDARD := y
KCOV_INSTRUMENT := n
-CFLAGS_vgettimeofday.o = -O2 -mcmodel=tiny
+CFLAGS_vgettimeofday.o = -O2 -mcmodel=tiny -fasynchronous-unwind-tables
ifneq ($(c-gettimeofday-y),)
CFLAGS_vgettimeofday.o += -include $(c-gettimeofday-y)
--
2.20.1
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prev parent reply other threads:[~2020-05-07 14:29 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20200507142830.26239-1-sashal@kernel.org>
2020-05-07 14:28 ` [PATCH AUTOSEL 5.4 22/35] i2c: iproc: generate stop event for slave writes Sasha Levin
2020-05-07 14:28 ` [PATCH AUTOSEL 5.4 32/35] i2c: aspeed: Avoid i2c interrupt status clear race condition Sasha Levin
2020-05-07 14:28 ` Sasha Levin [this message]
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