Re: [Qemu-devel] ppc: regression in 2.7.0-rc3 on rfi/rfid/hrfi instructions

[Benjamin Herrenschmidt <benh@kernel.crashing.org>]

On Wed, 2016-08-24 at 20:39 +0200, Hervé Poussineau wrote:
> Hi,
> 
> Following patch regresses Linux boot on PReP machine:

Where do I find the source for that kernel ?

Cheers,
Ben.

> commit a2e71b28e832346409efc795ecd1f0a2bcb705a3
> Author: Benjamin Herrenschmidt <benh@kernel.crashing.org>
> Date:   Tue Jun 21 23:48:46 2016 +0200
> 
>      ppc: Fix rfi/rfid/hrfi/... emulation
> 
>      This reworks emulation of the various "rfi" variants. I removed
>      some masking bits that I couldn't make sense of, the only bit
> that
>      I am aware we should mask here is POW, the CPU's MSR mask should
>      take care of the rest.
> 
>      This also fixes some problems when running 32-bit userspace
> under
>      a 64-bit kernel.
> 
>      This patch broke 32bit OpenBIOS when run under a 970 cpu. A fix
> was
>      proposed here :
> 
>          https://www.coreboot.org/pipermail/openbios/2016-June/009452
> .html
> 
>      Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
>      Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
>      [clg: updated the commit log with the reference of the openbios
> fix ]
>      Signed-off-by: Cédric Le Goater <clg@kaod.org>
>      [dwg: Remove hunk which disabled rfi on 64-bit CPUS.  The change
> was
>       correct, but we need to fix OpenBIOS before applying it]
>      Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
> 
> Test case:
> - Download: http://www.juneau-lug.org/zImage.initrd.sandalfoot
> - Run: qemu-system-ppc -M prep -kernel zImage.initrd.sandalfoot
> 
> Firmware starts, loads kernel, but seems to error out just after PS/2
> detection.
> 
> Reverting the commit and fixing the conflict makes it work again, up
> to shell.
> 
> Hervé