From: Marc Zyngier maz@kernel.org
[ Upstream commit 9d41053e8dc115c92b8002c3db5f545d7602498b ]
Although there has been a bit of back and forth on the subject, it appears that invalidating TLBs requires an ISB instruction when FEAT_ETS is not implemented by the CPU.
From the bible:
| In an implementation that does not implement FEAT_ETS, a TLB | maintenance instruction executed by a PE, PEx, can complete at any | time after it is issued, but is only guaranteed to be finished for a | PE, PEx, after the execution of DSB by the PEx followed by a Context | synchronization event
Add the missing ISB in __primary_switch, just in case.
Fixes: 3c5e9f238bc4 ("arm64: head.S: move KASLR processing out of __enable_mmu()") Suggested-by: Will Deacon will@kernel.org Signed-off-by: Marc Zyngier maz@kernel.org Acked-by: Mark Rutland mark.rutland@arm.com Link: https://lore.kernel.org/r/20210224093738.3629662-3-maz@kernel.org Signed-off-by: Will Deacon will@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- arch/arm64/kernel/head.S | 1 + 1 file changed, 1 insertion(+)
diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S index d22ab8d9edc95..c85ea70b92936 100644 --- a/arch/arm64/kernel/head.S +++ b/arch/arm64/kernel/head.S @@ -867,6 +867,7 @@ __primary_switch:
tlbi vmalle1 // Remove any stale TLB entries dsb nsh + isb
msr sctlr_el1, x19 // re-enable the MMU isb