[coreboot] [commit] r5612 - trunk/src/devices/oprom

[repository service]

Author: stepan
Date: Fri Jun  4 22:32:12 2010
New Revision: 5612
URL: https://tracker.coreboot.org/trac/coreboot/changeset/5612

Log:
This patch fixes the option rom code that was buggy when it switched
segment registers before restoring register values. This was breaking
the Geode VSA, and probably would have hurt other option roms as well.

Signed-off-by: Edwin Beasant <edwin_beasant at virtensys.com>
Acked-by: Patrick Georgi <patrick.georgi at coresystems.de>
Signed-off-by: Stefan Reinauer <stepan at coresystems.de>
Acked-by: Nils Jacobs <njacobs8 at hetnet.nl>

Modified:
   trunk/src/devices/oprom/x86_asm.S

Modified: trunk/src/devices/oprom/x86_asm.S
==============================================================================
--- trunk/src/devices/oprom/x86_asm.S	Fri Jun  4 22:24:11 2010	(r5611)
+++ trunk/src/devices/oprom/x86_asm.S	Fri Jun  4 22:32:12 2010	(r5612)
@@ -141,20 +141,23 @@
 	mov	%ax, %ds
 	lidt	__realmode_idt
 
-	/* Set all segments to 0x0000, ds to 0x0040 */
-	mov	%ax, %es
-	mov	%ax, %fs
-	mov	%ax, %gs
-	mov	$0x40, %ax
-	mov	%ax, %ds
-
 	/* initialize registers for option rom lcall */
 	movl	__registers +  0, %eax
 	movl	__registers +  4, %ebx
 	movl	__registers +  8, %ecx
 	movl	__registers + 12, %edx
 	movl	__registers + 16, %esi
-	movl	__registers + 20, %edi
+	movl	__registers + 20, %edi	
+
+	/* Set all segments to 0x0000, ds to 0x0040 */
+	push	%ax
+	xor	%ax, %ax
+	mov	%ax, %es
+	mov	%ax, %fs
+	mov	%ax, %gs
+	mov	$0x40, %ax
+	mov	%ax, %ds
+	pop	%ax
 
 	/* ************************************ */
 __lcall_instr = RELOCATED(.)
@@ -262,12 +265,6 @@
 	mov	%ax, %ds
 	lidt	__realmode_idt
 
-	/* Set all segments to 0x0000 */
-	mov	%ax, %ds
-	mov	%ax, %es
-	mov	%ax, %fs
-	mov	%ax, %gs
-
 	/* initialize registers for intXX call */
 	movl	__registers +  0, %eax
 	movl	__registers +  4, %ebx
@@ -276,6 +273,15 @@
 	movl	__registers + 16, %esi
 	movl	__registers + 20, %edi
 
+	/* Set all segments to 0x0000 */
+	push	%ax
+	xor	%ax, %ax
+	mov	%ax, %ds
+	mov	%ax, %es
+	mov	%ax, %fs
+	mov	%ax, %gs
+	pop	%ax
+
 __intXX_instr = RELOCATED(.)
 	.byte 0xcd, 0x00 /* This becomes intXX */
 
@@ -376,7 +382,7 @@
 	mov	%ax, %ds
 	lidt	__realmode_idt
 
-	/* Set up segment registers to segment 0x0000 */
+	/* Set up segment registers to segment 0x0000 and ds to 0x040 */
 	mov	%ax, %es
 	mov	%ax, %fs
 	mov	%ax, %gs