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H A D | context.c | a8e4c0a9 Fri Jan 19 09:42:09 CST 2018 Marc Zyngier <marc.zyngier@arm.com> arm64: Move BP hardening to check_and_switch_context
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> a8e4c0a9 Fri Jan 19 09:42:09 CST 2018 Marc Zyngier <marc.zyngier@arm.com> arm64: Move BP hardening to check_and_switch_context 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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