[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [PATCH 2/7] xen/arm32: head: Add mising isb in switch_to_runtime_mapping()
From: Julien Grall <jgrall@xxxxxxxxxx> Per the Arm Arm (ARM DDI 0406C.d A3.8.3): "The DMB and DSB memory barriers affect reads and writes to the memory system generated by load/store instructions and data or unified cache maintenance operations being executed by the processor. Instruction fetches or accesses caused by a hardware translation table access are not explicit accesses." The function switch_to_runtime_mapping() is responsible to map the Xen at its runtime address if we were using the temporary area before jumping returning using a runtime address. So we need to ensure the 'dsb' has completed before continuing. Therefore add an 'isb'. Fixes: fbd9b5fb4c26 ("xen/arm32: head: Remove restriction where to load Xen") Signed-off-by: Julien Grall <jgrall@xxxxxxxxxx> --- xen/arch/arm/arm32/head.S | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/xen/arch/arm/arm32/head.S b/xen/arch/arm/arm32/head.S index 6ca3329138e3..b942e7e54d08 100644 --- a/xen/arch/arm/arm32/head.S +++ b/xen/arch/arm/arm32/head.S @@ -656,6 +656,11 @@ switch_to_runtime_mapping: /* Ensure any page table updates are visible before continuing */ dsb nsh + /* + * The function will return on the runtime mapping. So we want + * to prevent instruction fetch before the dsb completes. + */ + isb ready_to_switch: mov pc, lr -- 2.40.1
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