| Message ID | 20191105235608.107702-13-samitolvanen@google.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v5,01/14] arm64: mm: avoid x18 in idmap_kpti_install_ng_mappings | expand |
On Tue, Nov 05, 2019 at 03:56:06PM -0800, Sami Tolvanen wrote: > Shadow stacks are only available in the kernel, so disable SCS > instrumentation for the vDSO. > > Signed-off-by: Sami Tolvanen <samitolvanen@google.com> > Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> > Reviewed-by: Kees Cook <keescook@chromium.org> I gave this a spin, looked at objdump, and found everything in the vDSO was a leaf function. I hacked the code around a bit to force a function call, and I see that just uses x29 and x30 as expected, with nothing touching x18. Reviewed-by: Mark Rutland <mark.rutland@arm.com> Mark. > --- > 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 dd2514bb1511..a87a4f11724e 100644 > --- a/arch/arm64/kernel/vdso/Makefile > +++ b/arch/arm64/kernel/vdso/Makefile > @@ -25,7 +25,7 @@ ccflags-y += -DDISABLE_BRANCH_PROFILING > > VDSO_LDFLAGS := -Bsymbolic > > -CFLAGS_REMOVE_vgettimeofday.o = $(CC_FLAGS_FTRACE) -Os > +CFLAGS_REMOVE_vgettimeofday.o = $(CC_FLAGS_FTRACE) -Os $(CC_FLAGS_SCS) > KBUILD_CFLAGS += $(DISABLE_LTO) > KASAN_SANITIZE := n > UBSAN_SANITIZE := n > -- > 2.24.0.rc1.363.gb1bccd3e3d-goog >
diff --git a/arch/arm64/kernel/vdso/Makefile b/arch/arm64/kernel/vdso/Makefile index dd2514bb1511..a87a4f11724e 100644 --- a/arch/arm64/kernel/vdso/Makefile +++ b/arch/arm64/kernel/vdso/Makefile @@ -25,7 +25,7 @@ ccflags-y += -DDISABLE_BRANCH_PROFILING VDSO_LDFLAGS := -Bsymbolic -CFLAGS_REMOVE_vgettimeofday.o = $(CC_FLAGS_FTRACE) -Os +CFLAGS_REMOVE_vgettimeofday.o = $(CC_FLAGS_FTRACE) -Os $(CC_FLAGS_SCS) KBUILD_CFLAGS += $(DISABLE_LTO) KASAN_SANITIZE := n UBSAN_SANITIZE := n