linux-stable.git/arch/powerpc, branch v3.2.22

powerpc: Fix kernel panic during kernel module load

2012-06-19T22:18:03+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: Ben Hutchings

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

2012-03-23T18:21:23+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

2012-03-01T00:30:49+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

2012-01-12T19:29:23+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

2012-01-12T19:29:22+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

procfs: do not confuse jiffies with cputime64_t

2011-12-30T00:31:57+00:00

Commit 2a95ea6c0d129b4 ("procfs: do not overflow get_{idle,iowait}_time
for nohz") did not take into account that one some architectures jiffies
and cputime use different units.

This causes get_idle_time() to return numbers in the wrong units, making
the idle time fields in /proc/stat wrong.

Instead of converting the usec value returned by
get_cpu_{idle,iowait}_time_us to units of jiffies, use the new function
usecs_to_cputime64 to convert it to the correct unit of cputime64_t.

Signed-off-by: Andreas Schwab 
Acked-by: Michal Hocko 
Cc: Arnd Bergmann 
Cc: "Artem S. Tashkinov" 
Cc: Dave Jones 
Cc: Alexey Dobriyan 
Cc: Thomas Gleixner 
Cc: "Luck, Tony" 
Cc: Benjamin Herrenschmidt 
Cc: Martin Schwidefsky 
Cc: Heiko Carstens 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

KVM: PPC: e500: include linux/export.h

2011-12-26T11:28:03+00:00

This is required for THIS_MODULE.  We recently stopped acquiring
it via some other header.

Signed-off-by: Scott Wood 
Signed-off-by: Alexander Graf

KVM: PPC: fix kvmppc_start_thread() for CONFIG_SMP=N

2011-12-26T11:28:02+00:00

Currently kvmppc_start_thread() tries to wake other SMT threads via
xics_wake_cpu().  Unfortunately xics_wake_cpu only exists when
CONFIG_SMP=Y so when compiling with CONFIG_SMP=N we get:

  arch/powerpc/kvm/built-in.o: In function `.kvmppc_start_thread':
  book3s_hv.c:(.text+0xa1e0): undefined reference to `.xics_wake_cpu'

The following should be fine since kvmppc_start_thread() shouldn't
called to start non-zero threads when SMP=N since threads_per_core=1.

Signed-off-by: Michael Neuling 
Signed-off-by: Alexander Graf

KVM: PPC: protect use of kvmppc_h_pr

2011-12-26T11:28:01+00:00

kvmppc_h_pr is only available if CONFIG_KVM_BOOK3S_64_PR.

Signed-off-by: Andreas Schwab 
Signed-off-by: Alexander Graf

KVM: PPC: move compute_tlbie_rb to book3s_64 common header

2011-12-26T11:28:00+00:00

compute_tlbie_rb is only used on ppc64 and cannot be compiled on ppc32.

Signed-off-by: Andreas Schwab 
Signed-off-by: Alexander Graf