soc: arm: viper: Fix callee saved register corruption in el3 init

x19 is callee saved register. z_arch_el3_plat_init being a callee, it should save it before using it. However, at this point, stack has not been setup. So, let's just use x20 instead which is not being used caller yet. This bug was causing VBAR_EL1 corruption, but since [10:0] bits are reserved, bug was hidden. Signed-off-by: Abhishek Shah <[email protected]>
niziak · Jul 13, 2020 · 3a63e85 · 3a63e85
1 parent 8344b80
commit 3a63e85
Showing 1 changed file with 2 additions and 2 deletions.
diff --git a/soc/arm/bcm_vk/viper/plat_core.S b/soc/arm/bcm_vk/viper/plat_core.S
@@ -20,15 +20,15 @@ GTEXT(plat_l2_init)
 
 SECTION_FUNC(TEXT, z_arch_el3_plat_init)
 
-	mov	x19, x30
+	mov	x20, x30
 	/* Enable GIC v3 system interface */
 	mov_imm	x0, (ICC_SRE_ELx_DFB | ICC_SRE_ELx_DIB | \
 		     ICC_SRE_ELx_SRE | ICC_SRE_EL3_EN)
 	msr	ICC_SRE_EL3, x0
 	/* L2 config */
 	bl	plat_l2_init
 
-	mov	x30, x19
+	mov	x30, x20
 	ret