Merge "aarch32: stop speculative execution past exception returns" into integration

2020-03-09 16:02:06 +00:00 · 2020-03-09 16:02:06 +00:00 · efe30cb1b4
parent 091576e7f1 6bc243825f
commit efe30cb1b4
4 changed files with 17 additions and 4 deletions
--- a/bl1/aarch32/bl1_exceptions.S
+++ b/bl1/aarch32/bl1_exceptions.S
@ -80,7 +80,7 @@ debug_loop:

 	add	r8, r8, #ENTRY_POINT_INFO_ARGS_OFFSET
 	ldm	r8, {r0, r1, r2, r3}
-	eret
+	exception_return
 endfunc bl1_aarch32_smc_handler

 	/* -----------------------------------------------------
--- a/bl2/aarch32/bl2_el3_entrypoint.S
+++ b/bl2/aarch32/bl2_el3_entrypoint.S
@ -87,5 +87,5 @@ func bl2_run_next_image

 	add	r8, r8, #ENTRY_POINT_INFO_ARGS_OFFSET
 	ldm	r8, {r0, r1, r2, r3}
-	eret
+	exception_return
 endfunc bl2_run_next_image
--- a/include/arch/aarch32/asm_macros.S
+++ b/include/arch/aarch32/asm_macros.S
@ -95,11 +95,24 @@

 #if ARM_ARCH_MAJOR == 7 && !defined(ARMV7_SUPPORTS_VIRTUALIZATION)
 	/*
+	 * Macro for mitigating against speculative execution.
 	 * ARMv7 cores without Virtualization extension do not support the
 	 * eret instruction.
 	 */
-	.macro eret
+	.macro exception_return
 	movs	pc, lr
+	dsb	nsh
+	isb
+	.endm
+
+#else
+	/*
+	 * Macro for mitigating against speculative execution beyond ERET.
+	 */
+	.macro exception_return
+	eret
+	dsb	nsh
+	isb
 	.endm
 #endif

--- a/include/arch/aarch32/smccc_macros.S
+++ b/include/arch/aarch32/smccc_macros.S
@ -235,7 +235,7 @@

 	/* Restore the rest of the general purpose registers */
 	ldm	r0, {r0-r12}
-	eret
+	exception_return
 	.endm

 #endif /* SMCCC_MACROS_S */