From: Vincenzo Frascino vincenzo.frascino@arm.com
commit 1578e5d03112e3e9d37e1c4d95b6dfb734c73955 upstream.
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: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- arch/arm64/kernel/vdso/Makefile | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- 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)