arm64/sme: Fix __finalise_el2 SMEver check

When checking for ID_AA64SMFR0_EL1.SMEver, __check_override assumes
that the ID_AA64SMFR0_EL1 value is in x1, and the intent of the code
is to reuse value read a few lines above.

However, as the comment says at the beginning of the macro, x1 will
be clobbered, and the checks always fails.

The easiest fix is just to reload the id register before checking it.

Fixes: f122576f3533 ("arm64/sme: Enable host kernel to access ZT0")
Signed-off-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

diff --git a/arch/arm64/kernel/hyp-stub.S b/arch/arm64/kernel/hyp-stub.S
index d31d1acb170d5e8c8d92f87c85208dd065c92528..111ff33d93ee74044921206b8ffc4c1868a0669c 100644 (file)
--- a/arch/arm64/kernel/hyp-stub.S
+++ b/arch/arm64/kernel/hyp-stub.S
@@ -133,6 +133,7 @@ SYM_CODE_START_LOCAL(__finalise_el2)
 .Lskip_sme_fa64:
 
        // ZT0 available?
+       mrs_s   x1, SYS_ID_AA64SMFR0_EL1
        __check_override id_aa64smfr0 ID_AA64SMFR0_EL1_SMEver_SHIFT 4 .Linit_sme_zt0 .Lskip_sme_zt0
 .Linit_sme_zt0:
        orr     x0, x0, SMCR_ELx_EZT0_MASK