[BISECTED] kexec regression on PowerBook G4

[Christophe Leroy]

Hi,

Le 22/05/2019 à 23:17, Aaro Koskinen a écrit :
> Hi,
> 
> On Wed, May 22, 2019 at 10:33:35PM +0200, LEROY Christophe wrote:
>> Can you provide full details of the Oops you get ? And also your System.map ?
> 
> System.map is below. The oops log is attached as jpeg (crappy camera
> shoot, apologies, I hope it gets through) as the only way I can see it
> is the frame buffer display.
> 
>> Also build with CONFIG_PPC_PTDUMP and mount /sys/kernel/debug and give
>> content of /sys/kernel/debug/powerpc/block_address_translation and
>> .../segment_registers before the failing kexec, and also
>> /sys/kernel/debug/kernel_page_tables
> 
> The kernel that fails is essentially headless without any input access. I
> could probably do this if needed, but it's going to take a while...
> 

Ok, the Oops confirms that the error is due to executing the kexec 
control code which is located outside the kernel text area.

My yesterday's proposed change doesn't work because on book3S/32, NX 
protection is based on setting segments to NX, and using IBATs for 
kernel text.

Can you try the patch I sent out a few minutes ago ? 
(https://patchwork.ozlabs.org/patch/1103827/)

Thanks
Christophe