Re: [coreboot] qemu-armv7: code execution out of RAM or ROM using latest QEMU
On Sun, Aug 10, 2014 at 02:35:46PM -0700, ron minnich wrote:
You can't assume much of anything. That commit seems not that harmful. What would help is if you tell us more about when the problem happens. There's just not enough info in your note, but I'd love to try to help.
I will try to do my best. Problem occurs at very early phase. There is no coreboot gdb support so I used qemu '-s -S'. Whole qemu command: qemu-system-arm -M vexpress-a9 -m 1024M -nographic -kernel build/coreboot.rom -s -S Exactly at address 0x6001024f qemu tries to execute: 0x60010249: adds r3, #1 0x6001024b: cmp r3, #7 0x6001024d: bne.n 0x6001019c => 0x6001024f: ldmia.w sp!, {r2, r3, r4, r5, r6, r7, r9, r10, r11, pc} 0x60010253: movs r3, #0 0x60010255: mcr 15, 0, r3, cr8, cr7, {0} 0x60010259: mcr 15, 0, r3, cr8, cr6, {0} 0x6001025d: mcr 15, 0, r3, cr8, cr5, {0} I can't find this instruction in coreboot code. Registers before executing ldmia: R0: 0x00000002 R1: 0x00000000 R2: 0xFFFFFFFE R3: 0x00000007 R4: 0x00000000 R5: 0x00000000 R6: 0x09000003 R7: 0x00000004 R8: 0x00000000 R9: 0x00000000 R10: 0x00000000 R11: 0x00000000 R12: 0x00000000 SP: 0x0007FEA8 LR: 0x6001032F PC: 0x6001024E And after: R0: 0x00000002 R1: 0x00000000 R2: 0x00000000 R3: 0x00000000 R4: 0x00000000 R5: 0x00000000 R6: 0x00000000 R7: 0x00000000 R8: 0x00000000 R9: 0x00000000 R10: 0x00000000 R11: 0x00000000 R12: 0x00000000 SP: 0x0007FED0 LR: 0x6001032F PC: 0x00000000 PC goes to 0 and we jumping to code where is 'andeq r0, r0, r0'. Qemu execute the same instruction till PC reach 0x4000000, then ends execution with:
qemu: fatal: Trying to execute code outside RAM or ROM at 0x04000000
Hope this is enough information. Thanks, Piotr
Piotr Król wrote:
Problem occurs at very early phase.
Hm.
There is no coreboot gdb support
There is some gdb support in coreboot, but maybe not for ARM?
so I used qemu '-s -S'. Whole qemu command:
qemu-system-arm -M vexpress-a9 -m 1024M -nographic -kernel build/coreboot.rom
Is -kernel really correct for coreboot.rom ? //Peter
On Mon, Aug 11, 2014 at 12:15:32AM +0200, Peter Stuge wrote:
There is no coreboot gdb support
There is some gdb support in coreboot, but maybe not for ARM?
What I tried to say is that it happens to early to connect to coreboot using gdb support, but maybe I'm wrong.
so I used qemu '-s -S'. Whole qemu command:
qemu-system-arm -M vexpress-a9 -m 1024M -nographic -kernel build/coreboot.rom
Is -kernel really correct for coreboot.rom ?
This is option from commit message when qemu-armv7 was introduced (7635a60). I also tried '-bios' but it gives same result but with different address (not 0x6001024f but 0x0000024f). What I see now is that I made mistake during bisect and it was not the correct commit that I point to. The correct change causing problem is exactly one before: http://git.qemu.org/?p=qemu.git;a=commit;h=6ec1588e09770ac7e9c60194faff61011... Sorry for confusion - first time bisect user. This commit is directly related to vexpress-a9 board. Piotr
So, if you comment that one line out, do things work for you? Just double checking. ron On Mon, Aug 11, 2014 at 2:09 AM, Piotr Król <pietrushnic@gmail.com> wrote:
On Mon, Aug 11, 2014 at 12:15:32AM +0200, Peter Stuge wrote:
There is no coreboot gdb support
There is some gdb support in coreboot, but maybe not for ARM?
What I tried to say is that it happens to early to connect to coreboot using gdb support, but maybe I'm wrong.
so I used qemu '-s -S'. Whole qemu command:
qemu-system-arm -M vexpress-a9 -m 1024M -nographic -kernel build/coreboot.rom
Is -kernel really correct for coreboot.rom ?
This is option from commit message when qemu-armv7 was introduced (7635a60). I also tried '-bios' but it gives same result but with different address (not 0x6001024f but 0x0000024f).
What I see now is that I made mistake during bisect and it was not the correct commit that I point to. The correct change causing problem is exactly one before:
http://git.qemu.org/?p=qemu.git;a=commit;h=6ec1588e09770ac7e9c60194faff61011...
Sorry for confusion - first time bisect user. This commit is directly related to vexpress-a9 board.
Piotr
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participants (3)
-
Peter Stuge -
Piotr Król -
ron minnich