4.8.0-rc1: Invalid memory access at $SRR0: 0140f86c $SRR1: 00003030

[Christian Kujau]

On Tue, 9 Aug 2016, Benjamin Herrenschmidt wrote:
> On Tue, 2016-08-09 at 02:06 -0700, Christian Kujau wrote:
> > On Mon, 8 Aug 2016, Christian Kujau wrote:
> > > 
> > > while trying to upgrade this PowerBook G4 from 4.7-rc7 to 4.8-rc1,
> > > it's 
> > > unable to boot the Yaboot (v1.3.16 from Debian/stable) boot loader:
> 
> There should already be a fix for that:
> http://patchwork.ozlabs.org/patch/654560/

2c0f99516f539 ("powerpc/32: Fix early access to cpu_spec relocation") is 
in mainline, but my machine is still unable to boot, same error, different address:

 > Invalid memory access at $SRR0: 0121686c $SRR1: 00003030 

Happy to test more patches :-)

Christian.

> It should be in Michael's tree if not already in Linus.
> 
> Cheers,
> Ben.
> 
> > > ================================================================
> > > copying OF device tree...
> > > Building dt strings...
> > > Building dt stucture...
> > > Device tree strings 0x01e72000 -> 0x01e73615
> > > Device tree struct  0x01e74000 -> 0x01e7e000
> > > Quiescing Open Firmware...
> > > Bootng Linux via __start()...
> > > 
> > > Invalid memory access at $SRR0: 0140f86c  $SRR1: 00003030
> > > 
> > > Apple PowerBook6,8 4.9.0f0 BootROM built on 01/10/05 at 10:39:14
> > > [...]
> > > 
> > >  ok
> > > 0:> _
> > > ================================================================
> > > 
> > > Going back to 4.7-rc7 (w/o installing Yaboot again) works just
> > > fine. The 
> > > config is mostly the same (used "make oldconfig" from 4.7), but
> > > I've said 
> > > YES to CONFIG_SLAB_FREELIST_RANDOM - could this be causing the
> > > boot 
> > > failure? Full .config and screen shot: http://nerdbynature.de/bits/
> > > 4.8.0-rc1/
> > 
> > A git-bisect led me to:
> > 
> > =========================================
> > commit 9402c684613163888714df0955fa1f17142b08bf
> > Author: Benjamin Herrenschmidt <benh at kernel.crashing.org>
> > Date:   Tue Jul 5 15:03:41 2016 +1000
> > 
> >     powerpc: Factor do_feature_fixup calls
> >     
> >     32 and 64-bit do a similar set of calls early on, we move it all
> > to
> >     a single common function to make the boot code more readable.
> >     
> >     Signed-off-by: Benjamin Herrenschmidt <benh at kernel.crashing.org>
> >     Signed-off-by: Michael Ellerman <mpe at ellerman.id.au>
> > =========================================
> > 
> > But I'm unable to revert just this patch:
> > 
> > $ git revert 9402c684613163888714df0955fa1f17142b08bf
> > error: could not revert 9402c68... powerpc: Factor do_feature_fixup
> > calls
> > hint: after resolving the conflicts, mark the corrected paths
> > 
> > The bisect-log:
> > 
> > =========================================
> > $ git bisect log
> > git bisect start '--' 'arch/powerpc'
> > # good: [523d939ef98fd712632d93a5a2b588e477a7565e] Linux 4.7
> > git bisect good 523d939ef98fd712632d93a5a2b588e477a7565e
> > # bad: [29b4817d4018df78086157ea3a55c1d9424a7cfc] Linux 4.8-rc1
> > git bisect bad 29b4817d4018df78086157ea3a55c1d9424a7cfc
> > # bad: [3808a88985b4f5f5e947c364debce4441a380fb8] powerpc: Move FW
> > feature probing out of pseries probe()
> > git bisect bad 3808a88985b4f5f5e947c364debce4441a380fb8
> > # good: [a203658b5ed37c11e5016d3fbbbab9ce018c1b78] powerpc/opal: Wake
> > up kopald polling thread before waiting for events
> > git bisect good a203658b5ed37c11e5016d3fbbbab9ce018c1b78
> > # good: [0dfffb48cecd8f84c6e649baee9bacd9be925734] powerpc/powernv:
> > abstraction for saving SPRs before entering deep idle states
> > git bisect good 0dfffb48cecd8f84c6e649baee9bacd9be925734
> > # good: [66c570f545e056babdd9510595ce762dcedadd71] powerpc/mm: use
> > _raw variant of page table accessors
> > git bisect good 66c570f545e056babdd9510595ce762dcedadd71
> > # good: [c2ca9f6b4cc4c45eb598b24b8b06beee668052d5] powerpc/powernv:
> > Fix pci-cxl.c build when CONFIG_MODULES=n
> > git bisect good c2ca9f6b4cc4c45eb598b24b8b06beee668052d5
> > # good: [4c91bd6eeabb004f283db8a6854b134e2a2de1bc] powerpc: Merge the
> > RELOCATABLE config entries for ppc32 and ppc64
> > git bisect good 4c91bd6eeabb004f283db8a6854b134e2a2de1bc
> > # bad: [c4bd6cb87c9e28a7d9f4a97db5a06cc538eb5e48] powerpc: Move 64-
> > bit feature fixup earlier
> > git bisect bad c4bd6cb87c9e28a7d9f4a97db5a06cc538eb5e48
> > # bad: [9402c684613163888714df0955fa1f17142b08bf] powerpc: Factor
> > do_feature_fixup calls
> > git bisect bad 9402c684613163888714df0955fa1f17142b08bf
> > # good: [27d1149667352772240655b65372a4294f992ea7] powerpc/32: Remove
> > RELOCATABLE_PPC32
> > git bisect good 27d1149667352772240655b65372a4294f992ea7
> > # first bad commit: [9402c684613163888714df0955fa1f17142b08bf]
> > powerpc: Factor do_feature_fixup calls
> > =========================================
> > 
> > 
> > HTH,
> > Christian.
> 

-- 
BOFH excuse #62:

need to wrap system in aluminum foil to fix problem