iv/linux
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

arm64: Document why we enable PAC support for leaf functions

Browse Source 
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>
This commit is contained in:
Mark Brown 2020-05-06 20:51:28 +01:00 committed by Will Deacon
parent e5159827e0
commit 717b938e22
1 changed files with 3 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
arch/arm64/Makefile
View File

@ -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