arm64: mte: remove an ISB on kernel exit

This ISB is unnecessary because we will soon do an ERET.

Signed-off-by: Peter Collingbourne <pcc@google.com>
Link: https://linux-review.googlesource.com/id/I69f1ee6bb09b1372dd744a0e01cedaf090c8d448
Link: https://lore.kernel.org/r/20201203073458.2675400-1-pcc@google.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S
index 2a93fa5..a8c3e7a 100644 (file)
--- a/arch/arm64/kernel/entry.S
+++ b/arch/arm64/kernel/entry.S
@@ -182,7 +182,6 @@ alternative_else_nop_endif
        mrs_s   \tmp2, SYS_GCR_EL1
        bfi     \tmp2, \tmp, #0, #16
        msr_s   SYS_GCR_EL1, \tmp2
-       isb
 #endif
        .endm
 
@@ -194,6 +193,7 @@ alternative_else_nop_endif
        ldr_l   \tmp, gcr_kernel_excl
 
        mte_set_gcr \tmp, \tmp2
+       isb
 1:
 #endif
        .endm