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| author | Mark Brown <broonie@kernel.org> | 2020-05-06 22:51:28 +0300 |
|---|---|---|
| committer | Will Deacon <will@kernel.org> | 2020-05-07 19:53:20 +0300 |
| commit | 717b938e22f8dbf0c02d51cb8e74634fac9b57ef (patch) | |
| tree | 3da9460f486699684e4c7a81466d6bdea8cbae8b | |
| parent | e5159827e057487359fc76f496a16ddbb8536cc9 (diff) | |
| download | linux-717b938e22f8dbf0c02d51cb8e74634fac9b57ef.tar.xz | |
arm64: Document why we enable PAC support for leaf functions
Document the fact that we enable pointer authentication protection for
leaf functions since there is some narrow potential for ROP protection
benefits and little overhead has been observed.
Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20200506195138.22086-2-broonie@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>
| -rw-r--r-- | arch/arm64/Makefile | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/arch/arm64/Makefile b/arch/arm64/Makefile index 85e4149cc5d5..921c8ee8552b 100644 --- a/arch/arm64/Makefile +++ b/arch/arm64/Makefile @@ -71,6 +71,9 @@ branch-prot-flags-y += $(call cc-option,-mbranch-protection=none) ifeq ($(CONFIG_ARM64_PTR_AUTH),y) branch-prot-flags-$(CONFIG_CC_HAS_SIGN_RETURN_ADDRESS) := -msign-return-address=all +# We enable additional protection for leaf functions as there is some +# narrow potential for ROP protection benefits and no substantial +# performance impact has been observed. branch-prot-flags-$(CONFIG_CC_HAS_BRANCH_PROT_PAC_RET) := -mbranch-protection=pac-ret+leaf # -march=armv8.3-a enables the non-nops instructions for PAC, to avoid the # compiler to generate them and consequently to break the single image contract |