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authorPeter Collingbourne <pcc@google.com>2020-11-21 01:59:02 -0800
committerCatalin Marinas <catalin.marinas@arm.com>2020-11-25 16:53:19 +0000
commit49b3cf035edc5d7deb3ad1bf6805ce456ababc5b (patch)
tree274247e95ef4c456f3ef4e8530929054138bfb1c /arch/arm64/mm/proc.S
parent739003c6428387432d42b9b80be185cde93978aa (diff)
downloadlinux-49b3cf035edc5d7deb3ad1bf6805ce456ababc5b.tar.bz2
kasan: arm64: set TCR_EL1.TBID1 when enabled
On hardware supporting pointer authentication, we previously ended up enabling TBI on instruction accesses when tag-based ASAN was enabled, but this was costing us 8 bits of PAC entropy, which was unnecessary since tag-based ASAN does not require TBI on instruction accesses. Get them back by setting TCR_EL1.TBID1. Signed-off-by: Peter Collingbourne <pcc@google.com> Reviewed-by: Andrey Konovalov <andreyknvl@google.com> Link: https://linux-review.googlesource.com/id/I3dded7824be2e70ea64df0aabab9598d5aebfcc4 Link: https://lore.kernel.org/r/20f64e26fc8a1309caa446fffcb1b4e2fe9e229f.1605952129.git.pcc@google.com Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Diffstat (limited to 'arch/arm64/mm/proc.S')
-rw-r--r--arch/arm64/mm/proc.S2
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/arm64/mm/proc.S b/arch/arm64/mm/proc.S
index 0eaf16b0442a..04945f72c64d 100644
--- a/arch/arm64/mm/proc.S
+++ b/arch/arm64/mm/proc.S
@@ -40,7 +40,7 @@
#define TCR_CACHE_FLAGS TCR_IRGN_WBWA | TCR_ORGN_WBWA
#ifdef CONFIG_KASAN_SW_TAGS
-#define TCR_KASAN_FLAGS TCR_TBI1
+#define TCR_KASAN_FLAGS TCR_TBI1 | TCR_TBID1
#else
#define TCR_KASAN_FLAGS 0
#endif