Re: [PATCH v5 17/17] powerpc/32s: Enable CONFIG_VMAP_STACK

[Christophe Leroy]

On 02/07/2020 01:44 PM, Guenter Roeck wrote:
> On 2/7/20 5:29 AM, Christophe Leroy wrote:
> > On 02/07/2020 01:08 PM, Guenter Roeck wrote:
> > > On 2/7/20 12:28 AM, Christophe Leroy wrote:
> > > > On 02/07/2020 06:13 AM, Christophe Leroy wrote:
> > > > > Le 06/02/2020 Ã 21:31, Guenter Roeck a ÃcritÂ:
> > > > > > 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@xxxxxx>
> > > > > >
> > > > > > 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 ?
> > > > >
> > > > > Before submitting the series, I successfully tested:
> > > > > - Real HW with powerpc 8xx
> > > > > - Real HW with powerpc 832x
> > > > > - Qemu's mac99
> > > > >
> > > > > I'll re-check the upstream kernel.
> > > >
> > > > This is still working for me with the upstream kernel:
> > >
> > > Interesting. What is your kernel configuration, your qemu version, and
> > > your qemu command line ?
> >
> > Config is pmac32_defconfig + CONFIG_DEVTMPFS (But kernel also boots 
> > without CONFIG_DEVTMPFS)
> >
> > QEMU emulator version 2.11.2
> >
> > qemu-system-ppc -kernel vmlinux -M mac99 -initrd rootfs.cpio.gz -s -m 
> > 1024
> >
> > Works with both GCC 5.5 and GCC 8.1
> Actually, the problem is that I have locking selftest options enabled
> in my tests. Everything works if I disable those. The "culprit" seems
> to be CONFIG_PROVE_LOCKING. Can you retest with CONFIG_PROVE_LOCKING=y ?

With CONFIG_PROVE_LOCKING, I get a deadlock after:

[...]
Kernel virtual memory layout:
  * 0xffbcf000..0xfffff000  : fixmap
  * 0xff400000..0xff800000  : highmem PTEs
  * 0xfeb36000..0xff400000  : early ioremap
  * 0xf1000000..0xfeb36000  : vmalloc & ioremap
SLUB: HWalign=32, Order=0-3, MinObjects=0, CPUs=1, Nodes=1
Running RCU self tests
NR_IRQS: 512, nr_irqs: 512, preallocated irqs: 16
mpic: Resetting
mpic: Setting up MPIC " MPIC 1   " version 1.2 at 80040000, max 1 CPUs
mpic: ISU size: 64, shift: 6, mask: 3f
mpic: Initializing for 64 sources
GMT Delta read from XPRAM: 0 minutes, DST: on
time_init: decrementer frequency = 100.000000 MHz
time_init: processor frequency   = 900.000000 MHz
clocksource: timebase: mask: 0xffffffffffffffff max_cycles: 
0x171024e7e0, max_idle_ns: 440795205315 ns
clocksource: timebase mult[a000000] shift[24] registered
clockevent: decrementer mult[1999999a] shift[32] cpu[0]
Console: colour dummy device 80x25
Lock dependency validator: Copyright (c) 2006 Red Hat, Inc., Ingo Molnar



Please test the patch I'll send out in a few minutes.

Thanks
Christophe