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| author | Ard Biesheuvel <ardb@kernel.org> | 2022-10-27 17:59:07 +0200 |
|---|---|---|
| committer | Will Deacon <will@kernel.org> | 2022-11-09 18:06:35 +0000 |
| commit | 9beccca0984022a844850e32f0d7dd80d4a225de (patch) | |
| tree | f9a9128498d40dee1958e15b212707872f039e38 /Makefile | |
| parent | 68c76ad4a9571a2b603665c85cf8229bcf04982a (diff) | |
| download | lwn-9beccca0984022a844850e32f0d7dd80d4a225de.tar.gz lwn-9beccca0984022a844850e32f0d7dd80d4a225de.zip | |
scs: add support for dynamic shadow call stacks
In order to allow arches to use code patching to conditionally emit the
shadow stack pushes and pops, rather than always taking the performance
hit even on CPUs that implement alternatives such as stack pointer
authentication on arm64, add a Kconfig symbol that can be set by the
arch to omit the SCS codegen itself, without otherwise affecting how
support code for SCS and compiler options (for register reservation, for
instance) are emitted.
Also, add a static key and some plumbing to omit the allocation of
shadow call stack for dynamic SCS configurations if SCS is disabled at
runtime.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Sami Tolvanen <samitolvanen@google.com>
Tested-by: Sami Tolvanen <samitolvanen@google.com>
Link: https://lore.kernel.org/r/20221027155908.1940624-3-ardb@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>
Diffstat (limited to 'Makefile')
| -rw-r--r-- | Makefile | 2 |
1 files changed, 2 insertions, 0 deletions
@@ -966,8 +966,10 @@ LDFLAGS_vmlinux += --gc-sections endif ifdef CONFIG_SHADOW_CALL_STACK +ifndef CONFIG_DYNAMIC_SCS CC_FLAGS_SCS := -fsanitize=shadow-call-stack KBUILD_CFLAGS += $(CC_FLAGS_SCS) +endif export CC_FLAGS_SCS endif |