[PATCH] ARM: V7M: Add dsb before jumping in handler mode

[Alexandre TORGUE]

According to ARM AN321 (section 4.12):

"If the vector table is in writable memory such as SRAM, either relocated
by VTOR or a device dependent memory remapping mechanism, then
architecturally a memory barrier instruction is required after the vector
table entry is updated, and if the exception is to be activated
immediately"

Signed-off-by: Maxime Coquelin <mcoquelin.stm32@xxxxxxxxx>
Signed-off-by: Alexandre TORGUE <alexandre.torgue@xxxxxx>

diff --git a/arch/arm/mm/proc-v7m.S b/arch/arm/mm/proc-v7m.S
index 7229d8d..2ddc435 100644
--- a/arch/arm/mm/proc-v7m.S
+++ b/arch/arm/mm/proc-v7m.S
@@ -104,6 +104,7 @@ __v7m_setup:
 	badr	r1, 1f
 	ldr	r5, [r12, #11 * 4]	@ read the SVC vector entry
 	str	r1, [r12, #11 * 4]	@ write the temporary SVC vector entry
+	dsb
 	mov	r6, lr			@ save LR
 	ldr	sp, =init_thread_union + THREAD_START_SP
 	cpsie	i
-- 
1.9.1