arm64: Force SSBS on context switch

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On a CPU that doesn't support SSBS, PSTATE[12] is RES0.  In a system
where only some of the CPUs implement SSBS, we end-up losing track of
the SSBS bit across task migration.

To address this issue, let's force the SSBS bit on context switch.

Fixes: 8f04e8e6e2 ("arm64: ssbd: Add support for PSTATE.SSBS rather than trapping to EL3")
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
[will: inverted logic and added comments]
Signed-off-by: Will Deacon <will@kernel.org>

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Marc Zyngier 2019-07-22 14:53:09 +01:00 • committed by Will Deacon

parent 4574b0b9ab

commit cbdf8a189a

2 changed files with 40 additions and 3 deletions

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14

arch/arm64/include/asm/processor.h

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29

arch/arm64/kernel/process.c

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