[v5,13/14] arm64: disable SCS for hypervisor code
diff mbox series

Message ID 20191105235608.107702-14-samitolvanen@google.com
State New
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Series
  • [v5,01/14] arm64: mm: avoid x18 in idmap_kpti_install_ng_mappings
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Commit Message

Sami Tolvanen Nov. 5, 2019, 11:56 p.m. UTC
Filter out CC_FLAGS_SCS for code that runs at a different exception
level.

Suggested-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
---
 arch/arm64/kvm/hyp/Makefile | 3 +++
 1 file changed, 3 insertions(+)

Comments

Mark Rutland Nov. 15, 2019, 2:46 p.m. UTC | #1
On Tue, Nov 05, 2019 at 03:56:07PM -0800, Sami Tolvanen wrote:
> Filter out CC_FLAGS_SCS for code that runs at a different exception
> level.
> 
> Suggested-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
> Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
> Reviewed-by: Kees Cook <keescook@chromium.org>

Looks sound, and objdump confirms that the hyp objects are using x29's
frame record, without using x18.

Reviewed-by: Mark Rutland <mark.rutland@arm.com>

Mark.

> ---
>  arch/arm64/kvm/hyp/Makefile | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/arch/arm64/kvm/hyp/Makefile b/arch/arm64/kvm/hyp/Makefile
> index ea710f674cb6..17ea3da325e9 100644
> --- a/arch/arm64/kvm/hyp/Makefile
> +++ b/arch/arm64/kvm/hyp/Makefile
> @@ -28,3 +28,6 @@ GCOV_PROFILE	:= n
>  KASAN_SANITIZE	:= n
>  UBSAN_SANITIZE	:= n
>  KCOV_INSTRUMENT	:= n
> +
> +# remove the SCS flags from all objects in this directory
> +KBUILD_CFLAGS := $(filter-out $(CC_FLAGS_SCS), $(KBUILD_CFLAGS))
> -- 
> 2.24.0.rc1.363.gb1bccd3e3d-goog
>

Patch
diff mbox series

diff --git a/arch/arm64/kvm/hyp/Makefile b/arch/arm64/kvm/hyp/Makefile
index ea710f674cb6..17ea3da325e9 100644
--- a/arch/arm64/kvm/hyp/Makefile
+++ b/arch/arm64/kvm/hyp/Makefile
@@ -28,3 +28,6 @@  GCOV_PROFILE	:= n
 KASAN_SANITIZE	:= n
 UBSAN_SANITIZE	:= n
 KCOV_INSTRUMENT	:= n
+
+# remove the SCS flags from all objects in this directory
+KBUILD_CFLAGS := $(filter-out $(CC_FLAGS_SCS), $(KBUILD_CFLAGS))