kasan: arm64: set TCR_EL1.TBID1 when enabled

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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>

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Peter Collingbourne 2020-11-21 01:59:02 -08:00 • committed by Catalin Marinas

parent 739003c642

commit 49b3cf035e

2 changed files with 2 additions and 1 deletions

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arch/arm64/include/asm/pgtable-hwdef.h

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2

arch/arm64/mm/proc.S

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