From: Sam Edwards <cfsworks@gmail.com>
Date: Sun, 28 May 2023 00:09:42 +0000 (-0600)
Subject: psci: fix use of clobbered registers in asm
X-Git-Url: http://git.dujemihanovic.xyz/%7B%7B%20%24style.Permalink%20%7D%7D?a=commitdiff_plain;h=8dc2c666808a07c2ad484ef6c4f89aa551eaf265;p=u-boot.git

psci: fix use of clobbered registers in asm

The functions `psci_get_context_id` and `psci_get_target_pc`
are written in C, so the C compiler may clobber registers r0-r3.
Do not use these registers to save data across calls.

Signed-off-by: Sam Edwards <CFSworks@gmail.com>
---

diff --git a/arch/arm/cpu/armv7/psci.S b/arch/arm/cpu/armv7/psci.S
index 6c066e50d9..41428728b7 100644
--- a/arch/arm/cpu/armv7/psci.S
+++ b/arch/arm/cpu/armv7/psci.S
@@ -311,11 +311,11 @@ ENTRY(psci_cpu_entry)
 	bl	psci_arch_cpu_entry
 
 	bl	psci_get_cpu_id			@ CPU ID => r0
-	mov	r2, r0				@ CPU ID => r2
 	bl	psci_get_context_id		@ context id => r0
-	mov	r1, r0				@ context id => r1
-	mov	r0, r2				@ CPU ID => r0
+	push	{r0}				@ save context id
+	bl	psci_get_cpu_id			@ CPU ID => r0
 	bl	psci_get_target_pc		@ target PC => r0
+	pop	{r1}				@ context id => r1
 	b	_do_nonsec_entry
 ENDPROC(psci_cpu_entry)