ARM: 8671/1: V7M: Preserve registers across switch from Thread to Han…

…dler mode According to ARMv7 ARM, when exception is taken content of r0-r3, r12 is unknown (see ExceptionTaken() pseudocode). Even though existent implementations keep these register unchanged, preserve them to be in line with architecture. Reported-by: Dobromir Stefanov <[email protected]> Signed-off-by: Vladimir Murzin <[email protected]> Signed-off-by: Russell King <[email protected]>
dabrace · Apr 26, 2017 · b70cd40 · b70cd40
1 parent 6f05d07
commit b70cd40
Showing 1 changed file with 2 additions and 0 deletions.
diff --git a/arch/arm/mm/proc-v7m.S b/arch/arm/mm/proc-v7m.S
@@ -135,9 +135,11 @@ __v7m_setup_cont:
 	dsb
 	mov	r6, lr			@ save LR
 	ldr	sp, =init_thread_union + THREAD_START_SP
+	stmia	sp, {r0-r3, r12}
 	cpsie	i
 	svc	#0
 1:	cpsid	i
+	ldmia	sp, {r0-r3, r12}
 	str	r5, [r12, #11 * 4]	@ restore the original SVC vector entry
 	mov	lr, r6			@ restore LR