From 9d41053e8dc115c92b8002c3db5f545d7602498b Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Wed, 24 Feb 2021 09:37:37 +0000 Subject: [PATCH] arm64: Add missing ISB after invalidating TLB in __primary_switch 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 Signed-off-by: Marc Zyngier Acked-by: Mark Rutland Link: https://lore.kernel.org/r/20210224093738.3629662-3-maz@kernel.org Signed-off-by: Will Deacon --- 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 1e30b55..66b0e0b 100644 --- a/arch/arm64/kernel/head.S +++ b/arch/arm64/kernel/head.S @@ -837,6 +837,7 @@ SYM_FUNC_START_LOCAL(__primary_switch) tlbi vmalle1 // Remove any stale TLB entries dsb nsh + isb set_sctlr_el1 x19 // re-enable the MMU -- 2.7.4