From 72c6071770da42334e2f0f41a1db35f53eb463d2 Mon Sep 17 00:00:00 2001
From: Patrick Rudolph <patrick.rudolph@9elements.com>
Date: Wed, 18 Nov 2020 13:26:10 +0100
Subject: [PATCH] cpu/x86/sipi_vector: Simplify loop getting unique CPU number

Get rid of using eax and reload counter on race condition.

Change-Id: Ie4b9957d8aa1f272ff1db5caf2c69d1e1f086a03
Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/47714
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>
Reviewed-by: Christian Walter <christian.walter@9elements.com>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
---
 src/cpu/x86/sipi_vector.S | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/src/cpu/x86/sipi_vector.S b/src/cpu/x86/sipi_vector.S
index 61d9e34466..02ad0d367a 100644
--- a/src/cpu/x86/sipi_vector.S
+++ b/src/cpu/x86/sipi_vector.S
@@ -84,10 +84,9 @@ _start:
 	mov	idt_ptr, %ebx
 	lidt	(%ebx)
 
-	/* Obtain CPU number. */
-	movl	ap_count, %eax
 1:
-	movl	%eax, %ecx
+	/* Obtain CPU number. */
+	movl	ap_count, %ecx
 	inc	%ecx
 	lock cmpxchg %ecx, ap_count
 	jnz	1b