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2010-05-12powerpc/perf_event: Fix oops due to perf_event_do_pending callPaul Mackerras
Anton Blanchard found that large POWER systems would occasionally crash in the exception exit path when profiling with perf_events. The symptom was that an interrupt would occur late in the exit path when the MSR[RI] (recoverable interrupt) bit was clear. Interrupts should be hard-disabled at this point but they were enabled. Because the interrupt was not recoverable the system panicked. The reason is that the exception exit path was calling perf_event_do_pending after hard-disabling interrupts, and perf_event_do_pending will re-enable interrupts. The simplest and cleanest fix for this is to use the same mechanism that 32-bit powerpc does, namely to cause a self-IPI by setting the decrementer to 1. This means we can remove the tests in the exception exit path and raw_local_irq_restore. This also makes sure that the call to perf_event_do_pending from timer_interrupt() happens within irq_enter/irq_exit. (Note that calling perf_event_do_pending from timer_interrupt does not mean that there is a possible 1/HZ latency; setting the decrementer to 1 ensures that the timer interrupt will happen immediately, i.e. within one timebase tick, which is a few nanoseconds or 10s of nanoseconds.) Signed-off-by: Paul Mackerras <paulus@samba.org> Cc: stable@kernel.org Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-10-30powerpc: Fix potential compile error irqs_disabled_flagsMichael Neuling
irqs_disabled_flags is #defined in linux/irqflags.h when CONFIG_TRACE_IRQFLAGS_SUPPORT is enabled. 64 and 32 bit always have CONFIG_TRACE_IRQFLAGS_SUPPORT enabled so just remove irqs_disabled_flags. This fixes the case when someone needs to include both linux/irqflags.h and asm/hw_irq.h. Signed-off-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-09-21perf: Do the big rename: Performance Counters -> Performance EventsIngo Molnar
Bye-bye Performance Counters, welcome Performance Events! In the past few months the perfcounters subsystem has grown out its initial role of counting hardware events, and has become (and is becoming) a much broader generic event enumeration, reporting, logging, monitoring, analysis facility. Naming its core object 'perf_counter' and naming the subsystem 'perfcounters' has become more and more of a misnomer. With pending code like hw-breakpoints support the 'counter' name is less and less appropriate. All in one, we've decided to rename the subsystem to 'performance events' and to propagate this rename through all fields, variables and API names. (in an ABI compatible fashion) The word 'event' is also a bit shorter than 'counter' - which makes it slightly more convenient to write/handle as well. Thanks goes to Stephane Eranian who first observed this misnomer and suggested a rename. User-space tooling and ABI compatibility is not affected - this patch should be function-invariant. (Also, defconfigs were not touched to keep the size down.) This patch has been generated via the following script: FILES=$(find * -type f | grep -vE 'oprofile|[^K]config') sed -i \ -e 's/PERF_EVENT_/PERF_RECORD_/g' \ -e 's/PERF_COUNTER/PERF_EVENT/g' \ -e 's/perf_counter/perf_event/g' \ -e 's/nb_counters/nb_events/g' \ -e 's/swcounter/swevent/g' \ -e 's/tpcounter_event/tp_event/g' \ $FILES for N in $(find . -name perf_counter.[ch]); do M=$(echo $N | sed 's/perf_counter/perf_event/g') mv $N $M done FILES=$(find . -name perf_event.*) sed -i \ -e 's/COUNTER_MASK/REG_MASK/g' \ -e 's/COUNTER/EVENT/g' \ -e 's/\<event\>/event_id/g' \ -e 's/counter/event/g' \ -e 's/Counter/Event/g' \ $FILES ... to keep it as correct as possible. This script can also be used by anyone who has pending perfcounters patches - it converts a Linux kernel tree over to the new naming. We tried to time this change to the point in time where the amount of pending patches is the smallest: the end of the merge window. Namespace clashes were fixed up in a preparatory patch - and some stylistic fallout will be fixed up in a subsequent patch. ( NOTE: 'counters' are still the proper terminology when we deal with hardware registers - and these sed scripts are a bit over-eager in renaming them. I've undone some of that, but in case there's something left where 'counter' would be better than 'event' we can undo that on an individual basis instead of touching an otherwise nicely automated patch. ) Suggested-by: Stephane Eranian <eranian@google.com> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Paul Mackerras <paulus@samba.org> Reviewed-by: Arjan van de Ven <arjan@linux.intel.com> Cc: Mike Galbraith <efault@gmx.de> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: David Howells <dhowells@redhat.com> Cc: Kyle McMartin <kyle@mcmartin.ca> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: <linux-arch@vger.kernel.org> LKML-Reference: <new-submission> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-08-20powerpc: Remaining 64-bit Book3E supportBenjamin Herrenschmidt
This contains all the bits that didn't fit in previous patches :-) This includes the actual exception handlers assembly, the changes to the kernel entry, other misc bits and wiring it all up in Kconfig. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-06-26powerpc: Add irqtrace support for 32-bit powerpcBenjamin Herrenschmidt
Based on initial work from: Dale Farnsworth <dale@farnsworth.org> Add the low level irq tracing hooks for 32-bit powerpc needed to enable full lockdep functionality. The approach taken to deal with the code in entry_32.S is that we don't trace all the transitions of MSR:EE when we just turn it off to peek at TI_FLAGS without races. Only when we are calling into C code or returning from exceptions with a state that have changed from what lockdep thinks. There's a little bugger though: If we take an exception that keeps interrupts enabled (such as an alignment exception) while interrupts are enabled, we will call trace_hardirqs_on() on the way back spurriously. Not a big deal, but to get rid of it would require remembering in pt_regs that the exception was one of the type that kept interrupts enabled which we don't know at this stage. (Well, we could test all cases for regs->trap but that sucks too much). Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Tested-by: Kumar Gala <galak@kernel.crashing.org>
2009-06-18perf_counter: powerpc: Enable use of software counters on 32-bit powerpcPaul Mackerras
This enables the perf_counter subsystem on 32-bit powerpc. Since we don't have any support for hardware counters on 32-bit powerpc yet, only software counters can be used. Besides selecting HAVE_PERF_COUNTERS for 32-bit powerpc as well as 64-bit, the main thing this does is add an implementation of set_perf_counter_pending(). This needs to arrange for perf_counter_do_pending() to be called when interrupts are enabled. Rather than add code to local_irq_restore as 64-bit does, the 32-bit set_perf_counter_pending() generates an interrupt by setting the decrementer to 1 so that a decrementer interrupt will become pending in 1 or 2 timebase ticks (if a decrementer interrupt isn't already pending). When interrupts are enabled, timer_interrupt() will be called, and some new code in there calls perf_counter_do_pending(). We use a per-cpu array of flags to indicate whether we need to call perf_counter_do_pending() or not. This introduces a couple of new Kconfig symbols: PPC_HAVE_PMU_SUPPORT, which is selected by processor families for which we have hardware PMU support (currently only PPC64), and PPC_PERF_CTRS, which enables the powerpc-specific perf_counter back-end. Signed-off-by: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: linuxppc-dev@ozlabs.org Cc: benh@kernel.crashing.org LKML-Reference: <19000.55404.103840.393470@cargo.ozlabs.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-06-17Merge branch 'linus' into perfcounters/coreIngo Molnar
Conflicts: arch/x86/include/asm/kmap_types.h include/linux/mm.h include/asm-generic/kmap_types.h Merge reason: We crossed changes with kmap_types.h cleanups in mainline. Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-06-15perf_counter: Make set_perf_counter_pending() declaration commonPaul Mackerras
At present, every architecture that supports perf_counters has to declare set_perf_counter_pending() in its arch-specific headers. This consolidates the declarations into a single declaration in one common place, include/linux/perf_counter.h. On powerpc, we continue to provide a static inline definition of set_perf_counter_pending() in the powerpc hw_irq.h. Also, this removes from the x86 perf_counter.h the unused null definitions of {test,clear}_perf_counter_pending. Reported-by: Mike Frysinger <vapier.adi@gmail.com> Signed-off-by: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: benh@kernel.crashing.org LKML-Reference: <18998.13388.920691.523227@cargo.ozlabs.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-06-15powerpc: Add compiler memory barrier to mtmsr macroPaul Mackerras
On 32-bit non-Book E, local_irq_restore() turns into just mtmsr(), which doesn't currently have a compiler memory barrier. This means that accesses to memory inside a local_irq_save/restore section, or a spin_lock_irqsave/spin_unlock_irqrestore section on UP, can be reordered by the compiler to occur outside that section. To fix this, this adds a compiler memory barrier to mtmsr for both 32-bit and 64-bit. Having a compiler memory barrier in mtmsr makes sense because it will almost always be changing something about the context in which memory accesses are done, so in general we don't want memory accesses getting moved from one side of an mtmsr to the other. With the barrier in mtmsr(), some of the explicit barriers in hw_irq.h are now redundant, so this removes them. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-06-11perfcounters: remove powerpc definitions of perf_counter_do_pendingStephen Rothwell
Commit 925d519ab82b6dd7aca9420d809ee83819c08db2 ("perf_counter: unify and fix delayed counter wakeup") added global definitions. Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au> Acked-by: Paul Mackerras <paulus@samba.org> Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-06perf_counter: unify and fix delayed counter wakeupPeter Zijlstra
While going over the wakeup code I noticed delayed wakeups only work for hardware counters but basically all software counters rely on them. This patch unifies and generalizes the delayed wakeup to fix this issue. Since we're dealing with NMI context bits here, use a cmpxchg() based single link list implementation to track counters that have pending wakeups. [ This should really be generic code for delayed wakeups, but since we cannot use cmpxchg()/xchg() in generic code, I've let it live in the perf_counter code. -- Eric Dumazet could use it to aggregate the network wakeups. ] Furthermore, the x86 method of using TIF flags was flawed in that its quite possible to end up setting the bit on the idle task, loosing the wakeup. The powerpc method uses per-cpu storage and does appear to be sufficient. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Paul Mackerras <paulus@samba.org> Orig-LKML-Reference: <20090330171023.153932974@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-04-06perf_counter: abstract wakeup flag setting in core to fix powerpc buildPaul Mackerras
Impact: build fix for powerpc Commit bd753921015e7905 ("perf_counter: software counter event infrastructure") introduced a use of TIF_PERF_COUNTERS into the core perfcounter code. This breaks the build on powerpc because we use a flag in a per-cpu area to signal wakeups on powerpc rather than a thread_info flag, because the thread_info flags have to be manipulated with atomic operations and are thus slower than per-cpu flags. This fixes the by changing the core to use an abstracted set_perf_counter_pending() function, which is defined on x86 to set the TIF_PERF_COUNTERS flag and on powerpc to set the per-cpu flag (paca->perf_counter_pending). It changes the previous powerpc definition of set_perf_counter_pending to not take an argument and adds a clear_perf_counter_pending, so as to simplify the definition on x86. On x86, set_perf_counter_pending() is defined as a macro. Defining it as a static inline in arch/x86/include/asm/perf_counters.h causes compile failures because <asm/perf_counters.h> gets included early in <linux/sched.h>, and the definitions of set_tsk_thread_flag etc. are therefore not available in <asm/perf_counters.h>. (On powerpc this problem is avoided by defining set_perf_counter_pending etc. in <asm/hw_irq.h>.) Signed-off-by: Paul Mackerras <paulus@samba.org>
2009-04-06Merge branch 'linus' into perfcounters/core-v2Ingo Molnar
Merge reason: we have gathered quite a few conflicts, need to merge upstream Conflicts: arch/powerpc/kernel/Makefile arch/x86/ia32/ia32entry.S arch/x86/include/asm/hardirq.h arch/x86/include/asm/unistd_32.h arch/x86/include/asm/unistd_64.h arch/x86/kernel/cpu/common.c arch/x86/kernel/irq.c arch/x86/kernel/syscall_table_32.S arch/x86/mm/iomap_32.c include/linux/sched.h kernel/Makefile Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-11powerpc/irq: Convert obsolete hw_interrupt_type to struct irq_chipThomas Gleixner
Impact: cleanup Convert the last remaining users to struct irq_chip. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> CC: Benjamin Herrenschmidt <benh@kernel.crashing.org> CC: linuxppc-dev@ozlabs.org Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2009-01-09powerpc: Provide a way to defer perf counter work until interrupts are enabledPaul Mackerras
Because 64-bit powerpc uses lazy (soft) interrupt disabling, it is possible for a performance monitor exception to come in when the kernel thinks interrupts are disabled (i.e. when they are soft-disabled but hard-enabled). In such a situation the performance monitor exception handler might have some processing to do (such as process wakeups) which can't be done in what is effectively an NMI handler. This provides a way to defer that work until interrupts get enabled, either in raw_local_irq_restore() or by returning from an interrupt handler to code that had interrupts enabled. We have a per-processor flag that indicates that there is work pending to do when interrupts subsequently get re-enabled. This flag is checked in the interrupt return path and in raw_local_irq_restore(), and if it is set, perf_counter_do_pending() is called to do the pending work. Signed-off-by: Paul Mackerras <paulus@samba.org>
2008-08-04powerpc: Move include files to arch/powerpc/include/asmStephen Rothwell
from include/asm-powerpc. This is the result of a mkdir arch/powerpc/include/asm git mv include/asm-powerpc/* arch/powerpc/include/asm Followed by a few documentation/comment fixups and a couple of places where <asm-powepc/...> was being used explicitly. Of the latter only one was outside the arch code and it is a driver only built for powerpc. Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Paul Mackerras <paulus@samba.org>