Re: [Qemu-devel] Commit 34b9c07a3 (microblaze: Disable stack protection from bootloader) causing qemu crash

[Guenter Roeck]

On 02/07/2014 06:31 PM, Edgar E. Iglesias wrote:
> On Fri, Feb 07, 2014 at 03:17:31PM -0800, Guenter Roeck wrote:
> > Michal,
> >
> > commit 34b9c07a3 (microblaze: Disable stack protection from bootloader) results
> > in the following qemu crash in 3.14-rc1.
> >
> > /opt/buildbot/bin/qemu-system-microblaze -M petalogix-s3adsp1800 -kernel 
> > arch/microblaze/boot/linux.bin -no-reboot -append "console=ttyUL0,115200 " 
> > -nographic
> > qemu: fatal: fetching nop sequence
> >
> > IN: PC=20
> > rmsr=4300 resr=7 rear=c0389fe8 debug=0 imm=ffffffd0 iflags=0 fsr=0
> > btaken=1 btarget=c03a9f24 mode=kernel(saved=kernel) eip=512 ie=0
> > r00=00000000 r01=c0389fcc r02=c0386a52 r03=000000c0
> > r04=00004100 r05=9052fab4 r06=00000000 r07=90530ab4
> > r08=00000000 r09=00400000 r10=00400000 r11=c03a9f24
> > r12=00621000 r13=40aef0c0 r14=00000000 r15=c0000294
> > r16=00000000 r17=c03a9f28 r18=00000000 r19=00000000
> > r20=00000000 r21=00000000 r22=00000000 r23=00000000
> > r24=00000000 r25=00000000 r26=00000000 r27=00000000
> > r28=00000000 r29=00400000 r30=00000300 r31=c03932d4
> >
> >
> > Aborted (core dumped)
> >
> > I have seen this with qemu 1.6.0 and 1.7.0.
> >
> > Reverting the patch solves the problem.
> >
> > Is this a qemu bug, a bug in the code, or a bug in my configuration ?
> > Any idea what I can do about it ?
>
> Hi Guenter,
>
> Seems to be a typo in the kernel, the following should fix it.
>
> Cheers,
> Edgar
>
> ---8<---
> From: "Edgar E. Iglesias" <address@hidden>
> Date: Sat, 8 Feb 2014 10:59:59 +1000
> Subject: [PATCH] microblaze: Fix a typo when disabling stack protection
>
> Correct a typo causing the stack protector to be left enabled.
> 0xFFFFFFF -> 0xFFFFFFFF
>
> Signed-off-by: Edgar E. Iglesias <address@hidden>

Hi Edgar,

you are right, that fixes the problem.

Tested-by: Guenter Roeck <address@hidden>

Thanks!
Guenter

> ---
>   arch/microblaze/kernel/head.S | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/microblaze/kernel/head.S b/arch/microblaze/kernel/head.S
> index b7fb043..17645b2 100644
> --- a/arch/microblaze/kernel/head.S
> +++ b/arch/microblaze/kernel/head.S
> @@ -66,7 +66,7 @@ real_start:
>         mts     rmsr, r0
>   /* Disable stack protection from bootloader */
>         mts     rslr, r0
> -       addi    r8, r0, 0xFFFFFFF
> +       addi    r8, r0, 0xFFFFFFFF
>         mts     rshr, r8
>   /*
>    * According to Xilinx, msrclr instruction behaves like 'mfs rX,rpc'