| Message ID | 20200429151050.31604-1-vincenzo.frascino@arm.com (mailing list archive) |
|---|---|
| State | Mainlined |
| Commit | 1578e5d03112e3e9d37e1c4d95b6dfb734c73955 |
| Headers | show |
| Series | [v2] arm64: vdso: Add -fasynchronous-unwind-tables to cflags | expand |
The 04/29/2020 16:10, Vincenzo Frascino wrote: > 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. > > Cc: Will Deacon <will@kernel.org> > Cc: Catalin Marinas <catalin.marinas@arm.com> > Reported-by: Szabolcs Nagy <szabolcs.nagy@arm.com> > Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com> thanks, the patch looks good to me. > --- > 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 77ee40f4c8b7..59555612fb1d 100644 > --- a/arch/arm64/kernel/vdso/Makefile > +++ b/arch/arm64/kernel/vdso/Makefile > @@ -35,7 +35,7 @@ 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 $(c-gettimeofday-y) > -- > 2.26.2 >
On Wed, Apr 29, 2020 at 04:10:50PM +0100, Vincenzo Frascino wrote: > On arm64 linux gcc uses -fasynchronous-unwind-tables -funwind-tables > by default since gcc-8, so now the de facto platform ABI is to allow > unwinding from async signal handlers. > > However on bare metal targets (aarch64-none-elf), and on old gcc, > async and sync unwind tables are not enabled by default to avoid > runtime memory costs. > > This means if linux is built with a baremetal toolchain the vdso.so > may not have unwind tables which breaks the gcc platform ABI guarantee > in userspace. > > Add -fasynchronous-unwind-tables explicitly to the vgettimeofday.o > cflags to address the ABI change. > > Cc: Will Deacon <will@kernel.org> > Cc: Catalin Marinas <catalin.marinas@arm.com> > Reported-by: Szabolcs Nagy <szabolcs.nagy@arm.com> > Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com> Queued for 5.7. Thanks.
diff --git a/arch/arm64/kernel/vdso/Makefile b/arch/arm64/kernel/vdso/Makefile index 77ee40f4c8b7..59555612fb1d 100644 --- a/arch/arm64/kernel/vdso/Makefile +++ b/arch/arm64/kernel/vdso/Makefile @@ -35,7 +35,7 @@ UBSAN_SANITIZE := n OBJECT_FILES_NON_STANDARD := y KCOV_INSTRUMENT := n -CFLAGS_vgettimeofday.o = -O2 -mcmodel=tiny +CFLAGS_vgettimeofday.o = -O2 -mcmodel=tiny -fasynchronous-unwind-tables ifneq ($(c-gettimeofday-y),) CFLAGS_vgettimeofday.o += -include $(c-gettimeofday-y)
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. Cc: Will Deacon <will@kernel.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Reported-by: Szabolcs Nagy <szabolcs.nagy@arm.com> Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com> --- arch/arm64/kernel/vdso/Makefile | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)