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@virtensys.com>
Acked-by: Patrick Georgi <patrick.georgi@coresystems.de>
Signed-off-by: Stefan Reinauer <stepan@coresystems.de>
Acked-by: Nils Jacobs <njacobs8@hetnet.nl>
git-svn-id: svn://svn.coreboot.org/coreboot/trunk@5612 2b7e53f0-3cfb-0310-b3e9-8179ed1497e1

diff --git a/src/devices/oprom/x86_asm.S b/src/devices/oprom/x86_asm.S
index bbae4b1bcec252369cc532af6cd56cc5ea6d19cf..e355da8fb909a8b027ca8ae112f8688589caa3d4 100644 (file)
--- a/src/devices/oprom/x86_asm.S
+++ b/src/devices/oprom/x86_asm.S
@@ -141,20 +141,23 @@ __realmode_call = RELOCATED(.)
        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 @@ __realmode_interrupt = RELOCATED(.)
        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 @@ __realmode_interrupt = RELOCATED(.)
        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 @@ __interrupt_handler_16bit = RELOCATED(.)
        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