commit bfe7bb6f70f4925bca6e2a78115a663e598e6bc8
author Madhukar Pappireddy <madhukar.pappireddy@arm.com> Tue Mar 10 18:04:59 2020 -0500
committer Madhukar Pappireddy <madhukar.pappireddy@arm.com> Wed Mar 11 11:11:05 2020 -0500
tree 12fad3e32c64aab395a370552da6a0230130cf7f
parent e6b1112ff9c0d7fc423aa4366baff89b31564d36

Use Speculation Barrier instruction for v8.5 cores

Change-Id: Ie1018bfbae2fe95c699e58648665baa75e862000
Signed-off-by: Madhukar Pappireddy <madhukar.pappireddy@arm.com>

include/arch/aarch32/asm_macros.S

diff --git a/include/arch/aarch32/asm_macros.S b/include/arch/aarch32/asm_macros.S
index ea1636e..f75da0c 100644
--- a/include/arch/aarch32/asm_macros.S
+++ b/include/arch/aarch32/asm_macros.S
@@ -108,11 +108,16 @@
 #else
 	/*
 	 * Macro for mitigating against speculative execution beyond ERET.
+	 * If possible use Speculation Barrier instruction defined in ARMv8.5
 	 */
 	.macro exception_return
 	eret
+#if ARM_ARCH_AT_LEAST(8, 5)
+	sb
+#else
 	dsb	nsh
 	isb
+#endif
 	.endm
 #endif
 

include/arch/aarch64/asm_macros.S

diff --git a/include/arch/aarch64/asm_macros.S b/include/arch/aarch64/asm_macros.S
index a7d5a3d..cbb9f0b 100644
--- a/include/arch/aarch64/asm_macros.S
+++ b/include/arch/aarch64/asm_macros.S
@@ -220,11 +220,16 @@
 
 	/*
 	 * Macro for mitigating against speculative execution beyond ERET.
+	 * If possible use Speculation Barrier instruction defined in ARMv8.5
 	 */
 	.macro exception_return
 	eret
-	dsb nsh
+#if ARM_ARCH_AT_LEAST(8, 5)
+	sb
+#else
+	dsb	nsh
 	isb
+#endif
 	.endm
 
 #endif /* ASM_MACROS_S */