linux-stable.git/arch/powerpc, branch v3.0.35

powerpc: Fix kernel panic during kernel module load

2012-06-17T18:23:10+00:00

commit 3c75296562f43e6fbc6cddd3de948a7b3e4e9bcf upstream.

This fixes a problem which can causes kernel oopses while loading
a kernel module.

According to the PowerPC EABI specification, GPR r11 is assigned
the dedicated function to point to the previous stack frame.
In the powerpc-specific kernel module loader, do_plt_call()
(in arch/powerpc/kernel/module_32.c), GPR r11 is also used
to generate trampoline code.

This combination crashes the kernel, in the case where the compiler
chooses to use a helper function for saving GPRs on entry, and the
module loader has placed the .init.text section far away from the
.text section, meaning that it has to generate a trampoline for
functions in the .init.text section to call the GPR save helper.
Because the trampoline trashes r11, references to the stack frame
using r11 can cause an oops.

The fix just uses GPR r12 instead of GPR r11 for generating the
trampoline code.  According to the statements from Freescale, this is
safe from an EABI perspective.

I've tested the fix for kernel 2.6.33 on MPC8541.

Signed-off-by: Steffen Rumler 
[paulus@samba.org: reworded the description]
Signed-off-by: Paul Mackerras 
Signed-off-by: Greg Kroah-Hartman

powerpc/pmac: Fix SMP kernels on pre-core99 UP machines

2012-03-23T18:20:52+00:00

commit 78c5c68a4cf4329d17abfa469345ddf323d4fd62 upstream.

The code for "powersurge" SMP would kick in and cause a crash
at boot due to the lack of a NULL test.

Signed-off-by: Benjamin Herrenschmidt 
Signed-off-by: Jeremy Kerr 
Reported-by: Adam Conrad 
Tested-by: Adam Conrad 
Signed-off-by: Greg Kroah-Hartman

powerpc/perf: power_pmu_start restores incorrect values, breaking frequency events

2012-03-01T00:33:39+00:00

commit 9a45a9407c69d068500923480884661e2b9cc421 upstream.

perf on POWER stopped working after commit e050e3f0a71b (perf: Fix
broken interrupt rate throttling). That patch exposed a bug in
the POWER perf_events code.

Since the PMCs count upwards and take an exception when the top bit
is set, we want to write 0x80000000 - left in power_pmu_start. We were
instead programming in left which effectively disables the counter
until we eventually hit 0x80000000. This could take seconds or longer.

With the patch applied I get the expected number of samples:

          SAMPLE events:       9948

Signed-off-by: Anton Blanchard 
Acked-by: Paul Mackerras 
Signed-off-by: Benjamin Herrenschmidt 
Signed-off-by: Greg Kroah-Hartman

powerpc: Fix unpaired probe_hcall_entry and probe_hcall_exit

2012-01-12T19:35:03+00:00

commit e4f387d8db3ba3c2dae4d8bdfe7bb5f4fe1bcb0d upstream.

Unpaired calling of probe_hcall_entry and probe_hcall_exit might happen
as following, which could cause incorrect preempt count.

__trace_hcall_entry => trace_hcall_entry -> probe_hcall_entry =>
get_cpu_var => preempt_disable

__trace_hcall_exit => trace_hcall_exit -> probe_hcall_exit =>
put_cpu_var => preempt_enable

where:
A => B and A -> B means A calls B, but
=> means A will call B through function name, and B will definitely be
called.
-> means A will call B through function pointer, so B might not be
called if the function pointer is not set.

So error happens when only one of probe_hcall_entry and probe_hcall_exit
get called during a hcall.

This patch tries to move the preempt count operations from
probe_hcall_entry and probe_hcall_exit to its callers.

Reported-by: Paul E. McKenney 
Signed-off-by: Li Zhong 
Tested-by: Paul E. McKenney 
Signed-off-by: Benjamin Herrenschmidt 
Signed-off-by: Greg Kroah-Hartman

powerpc/time: Handle wrapping of decrementer

2012-01-12T19:35:02+00:00

commit 37fb9a0231ee43d42d069863bdfd567fca2b61af upstream.

When re-enabling interrupts we have code to handle edge sensitive
decrementers by resetting the decrementer to 1 whenever it is negative.
If interrupts were disabled long enough that the decrementer wrapped to
positive we do nothing. This means interrupts can be delayed for a long
time until it finally goes negative again.

While we hope interrupts are never be disabled long enough for the
decrementer to go positive, we have a very good test team that can
drive any kernel into the ground. The softlockup data we get back
from these fails could be seconds in the future, completely missing
the cause of the lockup.

We already keep track of the timebase of the next event so use that
to work out if we should trigger a decrementer exception.

Signed-off-by: Anton Blanchard 
Signed-off-by: Benjamin Herrenschmidt 
Signed-off-by: Greg Kroah-Hartman

powerpc: Copy down exception vectors after feature fixups

2011-11-21T22:31:25+00:00

commit d715e433b7ad19c02fc4becf0d5e9a59f97925de upstream.

kdump fails because we try to execute an HV only instruction. Feature
fixups are being applied after we copy the exception vectors down to 0
so they miss out on any updates.

We have always had this issue but it only became critical in v3.0
when we added CFAR support (breaks POWER5) and v3.1 when we added
POWERNV (breaks everyone).

Signed-off-by: Anton Blanchard 
Signed-off-by: Benjamin Herrenschmidt 
Signed-off-by: Greg Kroah-Hartman

powerpc/ps3: Fix lost SMP IPIs

2011-11-21T22:31:25+00:00

commit 72f3bea075287785ed32b777b6dd2636aa7002e8 upstream.

Fixes the PS3 bootup hang introduced in 3.0-rc1 by:

  commit 317f394160e9beb97d19a84c39b7e5eb3d7815a
  sched: Move the second half of ttwu() to the remote cpu

Move the PS3's LV1 EOI call lv1_end_of_interrupt_ext() from ps3_chip_eoi()
to ps3_get_irq() for IPI messages.

If lv1_send_event_locally() is called between a previous call to
lv1_send_event_locally() and the coresponding call to
lv1_end_of_interrupt_ext() the second event will not be delivered to the
target cpu.

The PS3's SMP IPIs are implemented using lv1_send_event_locally(), so if two
IPI messages of the same type are sent to the same target in a relatively
short period of time the second IPI event can become lost when
lv1_end_of_interrupt_ext() is called from ps3_chip_eoi().

Signed-off-by: Geoff Levand 
Signed-off-by: Benjamin Herrenschmidt 
Signed-off-by: Greg Kroah-Hartman

powerpc: Fix deadlock in icswx code

2011-11-11T17:37:11+00:00

commit 8bdafa39a47265bc029838b35cc6585f69224afa upstream.

The icswx code introduced an A-B B-A deadlock:

     CPU0                    CPU1
     ----                    ----
lock(&anon_vma->mutex);
                             lock(&mm->mmap_sem);
                             lock(&anon_vma->mutex);
lock(&mm->mmap_sem);

Instead of using the mmap_sem to keep mm_users constant, take the
page table spinlock.

Signed-off-by: Anton Blanchard 
Signed-off-by: Benjamin Herrenschmidt 
Signed-off-by: Greg Kroah-Hartman

powerpc/eeh: Fix /proc/ppc64/eeh creation

2011-11-11T17:37:11+00:00

commit 8feaa43494cee5e938fd5a57b9e9bf1c827e6ccd upstream.

Since commit 188917e183cf9ad0374b571006d0fc6d48a7f447, /proc/ppc64 is a
symlink to /proc/powerpc/. That means that creating /proc/ppc64/eeh will
end up with a unaccessible file, that is not listed under /proc/powerpc/
and, then, not listed under /proc/ppc64/.

Creating /proc/powerpc/eeh fixes that problem and maintain the
compatibility intended with the ppc64 symlink.

Signed-off-by: Thadeu Lima de Souza Cascardo 
Signed-off-by: Benjamin Herrenschmidt 
Signed-off-by: Greg Kroah-Hartman

powerpc/pseries: Avoid spurious error during hotplug CPU add

2011-11-11T17:37:10+00:00

commit 9c740025c51a26ab00192cfc464064d4ccbfe3fc upstream.

During hotplug CPU add we get the following error:

Unexpected Error (0) returned from configure-connector

ibm,configure-connector returns 0 for configuration complete, so
catch this and avoid the error.

Signed-off-by: Anton Blanchard 
Signed-off-by: Benjamin Herrenschmidt 
Signed-off-by: Greg Kroah-Hartman