From: Marc Zyngier <maz@xxxxxxxxxx>
[ 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@xxxxxxxxxx>
Signed-off-by: Marc Zyngier <maz@xxxxxxxxxx>
Acked-by: Mark Rutland <mark.rutland@xxxxxxx>
Link: https://lore.kernel.org/r/20210224093738.3629662-3-maz@xxxxxxxxxx
Signed-off-by: Will Deacon <will@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
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 d8d9caf02834e..e7550a5289fef 100644
--- a/arch/arm64/kernel/head.S
+++ b/arch/arm64/kernel/head.S
@@ -985,6 +985,7 @@ SYM_FUNC_START_LOCAL(__primary_switch)
tlbi vmalle1 // Remove any stale TLB entries
dsb nsh
+ isb
msr sctlr_el1, x19 // re-enable the MMU
isb
--
2.27.0
