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| author | Sami Tolvanen <samitolvanen@google.com> | 2020-04-27 09:00:11 -0700 |
|---|---|---|
| committer | Will Deacon <will@kernel.org> | 2020-05-15 16:35:49 +0100 |
| commit | da64e9d1f8c3dad6898dac6edb39a68d3aa9ce93 (patch) | |
| tree | df04377d65e9c322df4a1fd0824ca27457427e99 /arch/arm64/Makefile | |
| parent | ddc9863e9e9025e2fc0c8dba31cc060cd626606f (diff) | |
| download | lwn-da64e9d1f8c3dad6898dac6edb39a68d3aa9ce93.tar.gz lwn-da64e9d1f8c3dad6898dac6edb39a68d3aa9ce93.zip | |
arm64: Reserve register x18 from general allocation with SCS
Reserve the x18 register from general allocation when SCS is enabled,
because the compiler uses the register to store the current task's
shadow stack pointer. Note that all external kernel modules must also be
compiled with -ffixed-x18 if the kernel has SCS enabled.
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Will Deacon <will@kernel.org>
Signed-off-by: Will Deacon <will@kernel.org>
Diffstat (limited to 'arch/arm64/Makefile')
| -rw-r--r-- | arch/arm64/Makefile | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/arch/arm64/Makefile b/arch/arm64/Makefile index 85e4149cc5d5..409a6c1be8cc 100644 --- a/arch/arm64/Makefile +++ b/arch/arm64/Makefile @@ -81,6 +81,10 @@ endif KBUILD_CFLAGS += $(branch-prot-flags-y) +ifeq ($(CONFIG_SHADOW_CALL_STACK), y) +KBUILD_CFLAGS += -ffixed-x18 +endif + ifeq ($(CONFIG_CPU_BIG_ENDIAN), y) KBUILD_CPPFLAGS += -mbig-endian CHECKFLAGS += -D__AARCH64EB__ |