commit f96972f2dc "kernel/sys.c: call disable_nonboot_cpus() in
kernel_restart()"
added a call to disable_nonboot_cpus() on kernel_restart(), which tries
to shutdown all the CPUs except the first one. The issue with the PA
Semi, is that it does not support CPU hotplug.
When the call is made to __cpu_down(), it calls the notifiers
CPU_DOWN_PREPARE, and then tries to take the CPU down.
One of the notifiers to the CPU hotplug code, is the cpufreq. The
DOWN_PREPARE will call __cpufreq_remove_dev() which calls
cpufreq_driver->exit. The PA Semi exit handler unmaps regions of I/O
that is used by an interrupt that goes off constantly
(system_reset_common, but it goes off during normal system operations
too). I'm not sure exactly what this interrupt does.
Running a simple function trace, you can see it goes off quite a bit:
# tracer: function
#
# TASK-PID CPU# TIMESTAMP FUNCTION
# | | | | |
<idle>-0 [001] 1558.859363: .pasemi_system_reset_exception <-.system_reset_exception
<idle>-0 [000] 1558.860112: .pasemi_system_reset_exception <-.system_reset_exception
<idle>-0 [000] 1558.861109: .pasemi_system_reset_exception <-.system_reset_exception
<idle>-0 [001] 1558.861361: .pasemi_system_reset_exception <-.system_reset_exception
<idle>-0 [000] 1558.861437: .pasemi_system_reset_exception <-.system_reset_exception
When the region is unmapped, the system crashes with:
Disabling non-boot CPUs ...
Error taking CPU1 down: -38
Unable to handle kernel paging request for data at address 0xd0000800903a0100
Faulting instruction address: 0xc000000000055fcc
Oops: Kernel access of bad area, sig: 11 [#1]
PREEMPT SMP NR_CPUS=64 NUMA PA Semi PWRficient
Modules linked in: shpchp
NIP: c000000000055fcc LR: c000000000055fb4 CTR: c0000000000df1fc
REGS: c0000000012175d0 TRAP: 0300 Not tainted (3.8.0-rc4-test-dirty)
MSR: 9000000000009032 <SF,HV,EE,ME,IR,DR,RI> CR: 24000088 XER: 00000000
SOFTE: 0
DAR: d0000800903a0100, DSISR: 42000000
TASK = c0000000010e9008[0] 'swapper/0' THREAD: c000000001214000 CPU: 0
GPR00: d0000800903a0000 c000000001217850 c0000000012167e0 0000000000000000
GPR04: 0000000000000000 0000000000000724 0000000000000724 0000000000000000
GPR08: 0000000000000000 0000000000000000 0000000000000001 0000000000a70000
GPR12: 0000000024000080 c00000000fff0000 ffffffffffffffff 000000003ffffae0
GPR16: ffffffffffffffff 0000000000a21198 0000000000000060 0000000000000000
GPR20: 00000000008fdd35 0000000000a21258 000000003ffffaf0 0000000000000417
GPR24: 0000000000a226d0 c000000000000000 0000000000000000 0000000000000000
GPR28: c00000000138b358 0000000000000000 c000000001144818 d0000800903a0100
NIP [c000000000055fcc] .set_astate+0x5c/0xa4
LR [c000000000055fb4] .set_astate+0x44/0xa4
Call Trace:
[c000000001217850] [c000000000055fb4] .set_astate+0x44/0xa4 (unreliable)
[c0000000012178f0] [c00000000005647c] .restore_astate+0x2c/0x34
[c000000001217980] [c000000000054668] .pasemi_system_reset_exception+0x6c/0x88
[c000000001217a00] [c000000000019ef0] .system_reset_exception+0x48/0x84
[c000000001217a80] [c000000000001e40] system_reset_common+0x140/0x180
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
So that we can clean up the header files and not be relying
on implicit includes from device.h ---> module.h
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Change &cpu_online_map to cpu_online_mask.
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
machine is compatible is an OF-specific call. It should have
the of_ prefix to protect the global namespace.
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Acked-by: Michal Simek <monstr@monstr.eu>
This updates the cpufreq drivers in arch/powerpc so they build again
after the core cpufreq changes that broke them in commit
in835481d9bcd65720b473db6b38746a74a3964218.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[Split from a larger patch - sfr]
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
When the PWRficient cpus are entered into powersavings states, the
astate is automatically dropped down to 0. While we still restore it
when we come out of idle, it can still cause some weird effects with
respect to performance (especially since it takes a while to ramp up to
higher astates).
So, to avoid this, don't enter power savings when the cpufreq driver
(or user) has set higher astates than 0.
The restore is still required, since there's a chance the astate has
been raised from the other cpu while the idling one was asleep.
Signed-off-by: Olof Johansson <olof@lixom.net>
There will be more product numbers in the future than just PA6T-1682M,
but they will share much of the features. Remove some of the explicit
references and compatibility checks with 1682M, and replace most of them
with the more generic term "PWRficient".
Signed-off-by: Olof Johansson <olof@lixom.net>
Acked-by: Michael Buesch <mb@bu3sch.de>
Acked-by: Doug Thompson <dougthompson@xmission.com>
Signed-off-by: Thomas Renninger <trenn@suse.de>
Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Bryan Wu <bryan.wu@analog.com>
Cc: Andi Kleen <ak@suse.de>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dave Jones <davej@redhat.com>
Update the global cpu speed variable according to current cpufreq speed,
/proc/cpuinfo reports the actual speed.
Signed-off-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Just another pass through arch/powerpc for old usages.
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Cpufreq driver for PA Semi PWRficient processors.
Signed-off-by: Egor Martovetsky <egor@pasemi.com>
Signed-off-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Paul Mackerras <paulus@samba.org>
