linux-stable.git/arch/powerpc/perf, branch linux-3.9.y

powerpc/perf: Fix deadlock caused by calling printk() in PMU exception

2013-06-13T17:49:28+00:00

commit 6772faa1ba22eba18d087c2459030a683b65be57 upstream.

In commit bc09c21 "Fix finding overflowed PMC in interrupt" we added
a printk() to the PMU exception handler. Unfortunately that is not safe.

The problem is that the PMU exception may run even when interrupts are
soft disabled, aka NMI context. We do this so that we can profile parts
of the kernel that have interrupts soft-disabled.

But by calling printk() from the exception handler, we can potentially
deadlock in the printk code on logbuf_lock, eg:

  [c00000038ba575c0] c000000000081928 .vprintk_emit+0xa8/0x540
  [c00000038ba576a0] c0000000007bcde8 .printk+0x48/0x58
  [c00000038ba57710] c000000000076504 .perf_event_interrupt+0x2d4/0x490
  [c00000038ba57810] c00000000001f6f8 .performance_monitor_exception+0x48/0x60
  [c00000038ba57880] c0000000000032cc performance_monitor_common+0x14c/0x180
  --- Exception: f01 (Performance Monitor) at c0000000007b25d4 ._raw_spin_lock_irq
  +0x64/0xc0
  [c00000038ba57bf0] c00000000007ed90 .devkmsg_read+0xd0/0x5a0
  [c00000038ba57d00] c0000000001c2934 .vfs_read+0xc4/0x1e0
  [c00000038ba57d90] c0000000001c2cd8 .SyS_read+0x58/0xd0
  [c00000038ba57e30] c000000000009d54 syscall_exit+0x0/0x98
  --- Exception: c01 (System Call) at 00001fffffbf6f7c
  SP (3ffff6d4de10) is in userspace

Fix it by making sure we only call printk() when we are not in NMI
context.

Signed-off-by: Michael Ellerman 
Signed-off-by: Benjamin Herrenschmidt 
Signed-off-by: Greg Kroah-Hartman

Merge tag 'perf-urgent-for-mingo' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux into perf/urgent

2013-03-18T09:00:56+00:00

Pull perf/urgent fixes from Arnaldo Carvalho de Melo:

. perf probe: Fix segfault due to testing the wrong pointer for NULL,
  from Ananth N Mavinakayanahalli.

. libtraceevent: Remove hard coded include to /usr/local/include in
  Makefile, which causes cross builds to include host header files,
  fix from Jack Mitchell.

. perf record: Use the right target interface for synthesizing
  threads when --cpu/-C option is used, fix from Jiri Olsa.

. Check if -DFORTIFY_SOURCE=2 is allowed, as gcc 4.7.2 defines
  it and then the build is broken when it is redefined in perf,
  fix from Marcin Slusarz.

. Fix build with NO_NEWT=1, that can happen explicitely or when
  the newt-devel package is not installed, from Michael Ellerman.

. perf/POWER7: Create a sysfs format entry for Power7 events, missing
  patch from a patchseries already merged, from Sukadev Bhattiprolu.

. Fix LIBNUMA build with glibc 2.12 and older, from Vinson Lee.

Signed-off-by: Arnaldo Carvalho de Melo 
Signed-off-by: Ingo Molnar

perf/POWER7: Create a sysfs format entry for Power7 events

2013-03-13T20:01:04+00:00

Create a sysfs entry, '/sys/bus/event_source/devices/cpu/format/event'
which describes the format of the POWER7 PMU events.

This code is based on corresponding code in x86.

Changelog[v4]:  [Michael Ellerman, Paul Mckerras] The event format is different
		for other POWER cpus. So move the code to POWER7-specific,
		power7-pmu.c Also, the POWER7 format uses bits 0-19 not 0-20.

Changelog[v2]: [Jiri Osla] Use PMU_FORMAT_ATTR rather than duplicating code.

Signed-off-by: Sukadev Bhattiprolu 
Acked-by: Paul Mackerras 
Tested-by: Michael Ellerman 
Cc: Andi Kleen 
Cc: Anton Blanchard 
Cc: Ingo Molnar 
Cc: Jiri Olsa 
Cc: Michael Ellerman 
Cc: Paul Mackerras 
Cc: Peter Zijlstra 
Cc: Robert Richter 
Cc: Stephane Eranian 
Cc: benh@kernel.crashing.org
Cc: linuxppc-dev@ozlabs.org
Link: http://lkml.kernel.org/r/20130306054826.GA14627@us.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo

Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc

2013-02-24T01:09:55+00:00

Pull powerpc updates from Benjamin Herrenschmidt:
 "So from the depth of frozen Minnesota, here's the powerpc pull request
  for 3.9.  It has a few interesting highlights, in addition to the
  usual bunch of bug fixes, minor updates, embedded device tree updates
  and new boards:

   - Hand tuned asm implementation of SHA1 (by Paulus & Michael
     Ellerman)

   - Support for Doorbell interrupts on Power8 (kind of fast
     thread-thread IPIs) by Ian Munsie

   - Long overdue cleanup of the way we handle relocation of our open
     firmware trampoline (prom_init.c) on 64-bit by Anton Blanchard

   - Support for saving/restoring & context switching the PPR (Processor
     Priority Register) on server processors that support it.  This
     allows the kernel to preserve thread priorities established by
     userspace.  By Haren Myneni.

   - DAWR (new watchpoint facility) support on Power8 by Michael Neuling

   - Ability to change the DSCR (Data Stream Control Register) which
     controls cache prefetching on a running process via ptrace by
     Alexey Kardashevskiy

   - Support for context switching the TAR register on Power8 (new
     branch target register meant to be used by some new specific
     userspace perf event interrupt facility which is yet to be enabled)
     by Ian Munsie.

   - Improve preservation of the CFAR register (which captures the
     origin of a branch) on various exception conditions by Paulus.

   - Move the Bestcomm DMA driver from arch powerpc to drivers/dma where
     it belongs by Philippe De Muyter

   - Support for Transactional Memory on Power8 by Michael Neuling
     (based on original work by Matt Evans).  For those curious about
     the feature, the patch contains a pretty good description."

(See commit db8ff907027b: "powerpc: Documentation for transactional
memory on powerpc" for the mentioned description added to the file
Documentation/powerpc/transactional_memory.txt)

* 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc: (140 commits)
  powerpc/kexec: Disable hard IRQ before kexec
  powerpc/85xx: l2sram - Add compatible string for BSC9131 platform
  powerpc/85xx: bsc9131 - Correct typo in SDHC device node
  powerpc/e500/qemu-e500: enable coreint
  powerpc/mpic: allow coreint to be determined by MPIC version
  powerpc/fsl_pci: Store the pci ctlr device ptr in the pci ctlr struct
  powerpc/85xx: Board support for ppa8548
  powerpc/fsl: remove extraneous DIU platform functions
  arch/powerpc/platforms/85xx/p1022_ds.c: adjust duplicate test
  powerpc: Documentation for transactional memory on powerpc
  powerpc: Add transactional memory to pseries and ppc64 defconfigs
  powerpc: Add config option for transactional memory
  powerpc: Add transactional memory to POWER8 cpu features
  powerpc: Add new transactional memory state to the signal context
  powerpc: Hook in new transactional memory code
  powerpc: Routines for FP/VSX/VMX unavailable during a transaction
  powerpc: Add transactional memory unavaliable execption handler
  powerpc: Add reclaim and recheckpoint functions for context switching transactional memory processes
  powerpc: Add FP/VSX and VMX register load functions for transactional memory
  powerpc: Add helper functions for transactional memory context switching
  ...

perf/POWER7: Make some POWER7 events available in sysfs

2013-01-31T16:07:51+00:00

Make some POWER7-specific perf events available in sysfs.

	$ /bin/ls -1 /sys/bus/event_source/devices/cpu/events/
	branch-instructions
	branch-misses
	cache-misses
	cache-references
	cpu-cycles
	instructions
	PM_BRU_FIN
	PM_BRU_MPRED
	PM_CMPLU_STALL
	PM_CYC
	PM_GCT_NOSLOT_CYC
	PM_INST_CMPL
	PM_LD_MISS_L1
	PM_LD_REF_L1
	stalled-cycles-backend
	stalled-cycles-frontend

where the 'PM_*' events are POWER specific and the others are the
generic events.

This will enable users to specify these events with their symbolic
names rather than with their raw code.

	perf stat -e 'cpu/PM_CYC' ...

Signed-off-by: Sukadev Bhattiprolu 
Cc: Andi Kleen 
Cc: Anton Blanchard 
Cc: Ingo Molnar 
Cc: Jiri Olsa 
Cc: Paul Mackerras 
Cc: Peter Zijlstra 
Cc: Robert Richter 
Cc: Stephane Eranian 
Cc: linuxppc-dev@ozlabs.org
Link: http://lkml.kernel.org/r/20130123062528.GE13720@us.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo

perf/POWER7: Make generic event translations available in sysfs

2013-01-31T16:07:50+00:00

Make the generic perf events in POWER7 available via sysfs.

	$ ls /sys/bus/event_source/devices/cpu/events
	branch-instructions
	branch-misses
	cache-misses
	cache-references
	cpu-cycles
	instructions
	stalled-cycles-backend
	stalled-cycles-frontend

	$ cat /sys/bus/event_source/devices/cpu/events/cache-misses
	event=0x400f0

This patch is based on commits that implement this functionality on x86.
Eg:
	commit a47473939db20e3961b200eb00acf5fcf084d755
	Author: Jiri Olsa 
	Date:   Wed Oct 10 14:53:11 2012 +0200

	    perf/x86: Make hardware event translations available in sysfs

Changelog:[v2]
	[Jiri Osla] Drop EVENT_ID() macro since it is only used once.

Signed-off-by: Sukadev Bhattiprolu 
Cc: Andi Kleen 
Cc: Anton Blanchard 
Cc: Ingo Molnar 
Cc: Jiri Olsa 
Cc: Paul Mackerras 
Cc: Peter Zijlstra 
Cc: Robert Richter 
Cc: Stephane Eranian 
Cc: linuxppc-dev@ozlabs.org
Link: http://lkml.kernel.org/r/20130123062454.GD13720@us.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo

perf/Power7: Use macros to identify perf events

2013-01-31T16:07:50+00:00

Define and use macros to identify perf events codes This would make it
easier and more readable when these event codes need to be used in more
than one place.

Signed-off-by: Sukadev Bhattiprolu 
Acked-by: Jiri Olsa 
Cc: Andi Kleen 
Cc: Anton Blanchard 
Cc: Ingo Molnar 
Cc: Jiri Olsa 
Cc: Paul Mackerras 
Cc: Peter Zijlstra 
Cc: Robert Richter 
Cc: Stephane Eranian 
Cc: linuxppc-dev@ozlabs.org
Link: http://lkml.kernel.org/r/20130123062353.GB13720@us.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo

perf/Power: PERF_EVENT_IOC_ENABLE does not reenable event

2013-01-29T00:35:07+00:00

perf/Power: PERF_EVENT_IOC_ENABLE does not reenable event

If we disable a perf event because we exceeded the specified ->event_limit,
power_pmu_stop() sets the PERF_HES_STOPPED flag on the event.

If the application then re-enables the event using PERF_EVENT_IOC_ENABLE
ioctl, we don't ever clear this STOPPED flag. Consequently, the user space
is never notified of the event.

Following message has more background and test case.

    http://lists.eecs.utk.edu/pipermail/ptools-perfapi/2012-October/002528.html

Used the following test cases to verify that this patch works on latest PAPI.

	$ papi.git/src/ctests/nonthread PAPI_TOT_CYC@5000000

	$ papi.git/src/ctests/overflow_single_event

Changelog[v2]:
	- [Paul Mackerras] Also clear PERF_HES_UPTODATE flag since we are
	  restarting the event; cleanup comments and patch description.

Signed-off-by: Sukadev Bhattiprolu 
Signed-off-by: Benjamin Herrenschmidt

powerpc/perf: Fix for PMCs not making progress

2013-01-10T06:02:04+00:00

On POWER7 when we have really small counts left before overflow, we can take a
PMU IRQ, but the PMC gets wound back to just before the overflow.

If the kernel is setting the PMC to a value just before the overflow, we can
get interrupted again without the PMC making any progress (ie another buggy
overflow).  In this case, we can end up making no forward progress, with the
PMC interrupt returning us to the same count over and over.

The below detects when we are making no forward progress (ie. delta = 0) and
then increases the amount left before the overflow.  This stops us from locking
up.

Signed-off-by: Michael Neuling 
Reviewed-by: Sukadev Bhattiprolu 
cc: Paul Mackerras 
cc: Anton Blanchard 
cc: Linux PPC dev 
Signed-off-by: Benjamin Herrenschmidt

powerpc/perf: Fix finding overflowed PMC in interrupt

2013-01-10T06:02:01+00:00

If a PMC is about to overflow on a counter that's on an active perf event
(ie. less than 256 from the end) and a _different_ PMC overflows just at this
time (a PMC that's not on an active perf event), we currently mark the event as
found, but in reality it's not as it's likely the other PMC that caused the
IRQ.  Since we mark it as found the second catch all for overflows doesn't run,
and we don't reset the overflowing PMC ever.  Hence we keep hitting that same
PMC IRQ over and over and don't reset the actual overflowing counter.

This is a rewrite of the perf interrupt handler for book3s to get around this.
We now check to see if any of the PMCs have actually overflowed (ie >=
0x80000000).  If yes, record it for active counters and just reset it for
inactive counters.  If it's not overflowed, then we check to see if it's one of
the buggy power7 counters and if it is, record it and continue.  If none of the
PMCs match this, then we make note that we couldn't find the PMC that caused
the IRQ.

Signed-off-by: Michael Neuling 
Reviewed-by: Sukadev Bhattiprolu 
cc: Paul Mackerras 
cc: Anton Blanchard 
cc: Linux PPC dev 
Signed-off-by: Benjamin Herrenschmidt