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Date:   Thu, 6 Feb 2020 12:31:46 -0800
From:   Guenter Roeck <linux@roeck-us.net>
To:     Christophe Leroy <christophe.leroy@c-s.fr>
Cc:     Benjamin Herrenschmidt <benh@kernel.crashing.org>,
        Paul Mackerras <paulus@samba.org>,
        Michael Ellerman <mpe@ellerman.id.au>, dja@axtens.net,
        linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
        linux-mm@kvack.org
Subject: Re: [PATCH v5 17/17] powerpc/32s: Enable CONFIG_VMAP_STACK
Message-ID: <20200206203146.GA23248@roeck-us.net>
References: <cover.1576916812.git.christophe.leroy@c-s.fr>
 <2e2509a242fd5f3e23df4a06530c18060c4d321e.1576916812.git.christophe.leroy@c-s.fr>
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On Sat, Dec 21, 2019 at 08:32:38AM +0000, Christophe Leroy wrote:
> A few changes to retrieve DAR and DSISR from struct regs
> instead of retrieving them directly, as they may have
> changed due to a TLB miss.
> 
> Also modifies hash_page() and friends to work with virtual
> data addresses instead of physical ones. Same on load_up_fpu()
> and load_up_altivec().
> 
> Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>

This patch results in qemu boot failures (mac99 with pmac32_defconfig).
Images fail silently; there is no console output. Reverting the patch
fixes the problem. Bisect log is attached below.

Assuming this was tested on real hardware, am I correct to assume that qemu
for ppc32 (more specifically, qemu's mac99 and g3beige machines) no longer
works with the upstream kernel ?

Thanks,
Guenter

---
# bad: [33b40134e5cfbbccad7f3040d1919889537a3df7] Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
# good: [d4e9056daedca3891414fe3c91de3449a5dad0f2] initramfs: do not show compression mode choice if INITRAMFS_SOURCE is empty
git bisect start '33b40134e5cf' 'd4e9056daedc'
# good: [9717c1cea16e3eae81ca226f4c3670bb799b61ad] Merge tag 'drm-next-2020-02-04' of git://anongit.freedesktop.org/drm/drm
git bisect good 9717c1cea16e3eae81ca226f4c3670bb799b61ad
# bad: [4c25df5640ae6e4491ee2c50d3f70c1559ef037d] Merge branch 'topic/user-access-begin' into next
git bisect bad 4c25df5640ae6e4491ee2c50d3f70c1559ef037d
# good: [846a17a53aeeee426cbc1252f517a6660eab1427] powerpc/powernv: Use common code for the symbol_map export
git bisect good 846a17a53aeeee426cbc1252f517a6660eab1427
# good: [afe1ec5ab83029baf0f8368a255dc6b998bde576] powerpc/8xx: Split breakpoint exception
git bisect good afe1ec5ab83029baf0f8368a255dc6b998bde576
# bad: [43e76cd368fbb67e767da5363ffeaa3989993c8c] powerpc: Do not consider weak unresolved symbol relocations as bad
git bisect bad 43e76cd368fbb67e767da5363ffeaa3989993c8c
# bad: [af1725d2493dcad4eeb7e63141678181fcd8a2ff] powerpc/kconfig: Move CONFIG_PPC32 into Kconfig.cputype
git bisect bad af1725d2493dcad4eeb7e63141678181fcd8a2ff
# good: [94dd54c51a410b9ffa6356c3ed2ab0317f998ded] powerpc/32s: Avoid crossing page boundary while changing SRR0/1.
git bisect good 94dd54c51a410b9ffa6356c3ed2ab0317f998ded
# bad: [0f9aee0cb9da7db7d96f63cfa2dc5e4f1bffeb87] powerpc/mm: Don't log user reads to 0xffffffff
git bisect bad 0f9aee0cb9da7db7d96f63cfa2dc5e4f1bffeb87
# bad: [cd08f109e26231b279bcc0388428afcac6408ec6] powerpc/32s: Enable CONFIG_VMAP_STACK
git bisect bad cd08f109e26231b279bcc0388428afcac6408ec6
# first bad commit: [cd08f109e26231b279bcc0388428afcac6408ec6] powerpc/32s: Enable CONFIG_VMAP_STACK