arm64: Move BP hardening to check_and_switch_context

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We call arm64_apply_bp_hardening() from post_ttbr_update_workaround,
which has the unexpected consequence of being triggered on every
exception return to userspace when ARM64_SW_TTBR0_PAN is selected,
even if no context switch actually occured.

This is a bit suboptimal, and it would be more logical to only
invalidate the branch predictor when we actually switch to
a different mm.

In order to solve this, move the call to arm64_apply_bp_hardening()
into check_and_switch_context(), where we're guaranteed to pick
a different mm context.

Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

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Marc Zyngier 2018-01-19 15:42:09 +00:00 • committed by Catalin Marinas

parent e9eaa8052f

commit a8e4c0a919

1 changed files with 3 additions and 2 deletions

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arch/arm64/mm/context.c

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