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authorPaul Mackerras <paulus@samba.org>2009-06-17 21:50:04 +1000
committerIngo Molnar <mingo@elte.hu>2009-06-18 11:11:44 +0200
commit105988c015943e77092a6568bc5fb7e386df6ccd (patch)
treebd352fe5e68a66de2e08a8b91c8f8cccf422f346
parenta73c7d84a1975b44c0ebd03c2dec288af1426349 (diff)
perf_counter: powerpc: Enable use of software counters on 32-bit powerpc
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>
-rw-r--r--arch/powerpc/Kconfig1
-rw-r--r--arch/powerpc/include/asm/hw_irq.h5
-rw-r--r--arch/powerpc/include/asm/perf_counter.h10
-rw-r--r--arch/powerpc/kernel/Makefile6
-rw-r--r--arch/powerpc/kernel/time.c25
-rw-r--r--arch/powerpc/platforms/Kconfig.cputype11
6 files changed, 51 insertions, 7 deletions
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 9fb344d5a86..bf6cedfa05d 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -126,6 +126,7 @@ config PPC
select HAVE_OPROFILE
select HAVE_SYSCALL_WRAPPERS if PPC64
select GENERIC_ATOMIC64 if PPC32
+ select HAVE_PERF_COUNTERS
config EARLY_PRINTK
bool
diff --git a/arch/powerpc/include/asm/hw_irq.h b/arch/powerpc/include/asm/hw_irq.h
index 10a642df014..867ab8ed69b 100644
--- a/arch/powerpc/include/asm/hw_irq.h
+++ b/arch/powerpc/include/asm/hw_irq.h
@@ -131,6 +131,8 @@ static inline int irqs_disabled_flags(unsigned long flags)
struct irq_chip;
#ifdef CONFIG_PERF_COUNTERS
+
+#ifdef CONFIG_PPC64
static inline unsigned long test_perf_counter_pending(void)
{
unsigned long x;
@@ -154,8 +156,9 @@ static inline void clear_perf_counter_pending(void)
"r" (0),
"i" (offsetof(struct paca_struct, perf_counter_pending)));
}
+#endif /* CONFIG_PPC64 */
-#else
+#else /* CONFIG_PERF_COUNTERS */
static inline unsigned long test_perf_counter_pending(void)
{
diff --git a/arch/powerpc/include/asm/perf_counter.h b/arch/powerpc/include/asm/perf_counter.h
index b398a84edce..2c2d9f643df 100644
--- a/arch/powerpc/include/asm/perf_counter.h
+++ b/arch/powerpc/include/asm/perf_counter.h
@@ -57,11 +57,17 @@ extern struct power_pmu *ppmu;
struct pt_regs;
extern unsigned long perf_misc_flags(struct pt_regs *regs);
-#define perf_misc_flags(regs) perf_misc_flags(regs)
-
extern unsigned long perf_instruction_pointer(struct pt_regs *regs);
/*
+ * Only override the default definitions in include/linux/perf_counter.h
+ * if we have hardware PMU support.
+ */
+#ifdef CONFIG_PPC_PERF_CTRS
+#define perf_misc_flags(regs) perf_misc_flags(regs)
+#endif
+
+/*
* The power_pmu.get_constraint function returns a 64-bit value and
* a 64-bit mask that express the constraints between this event and
* other events.
diff --git a/arch/powerpc/kernel/Makefile b/arch/powerpc/kernel/Makefile
index 612b0c4dc26..c5f93f06192 100644
--- a/arch/powerpc/kernel/Makefile
+++ b/arch/powerpc/kernel/Makefile
@@ -95,9 +95,9 @@ obj64-$(CONFIG_AUDIT) += compat_audit.o
obj-$(CONFIG_DYNAMIC_FTRACE) += ftrace.o
obj-$(CONFIG_FUNCTION_GRAPH_TRACER) += ftrace.o
-obj-$(CONFIG_PERF_COUNTERS) += perf_counter.o power4-pmu.o ppc970-pmu.o \
- power5-pmu.o power5+-pmu.o power6-pmu.o \
- power7-pmu.o
+obj-$(CONFIG_PPC_PERF_CTRS) += perf_counter.o
+obj64-$(CONFIG_PPC_PERF_CTRS) += power4-pmu.o ppc970-pmu.o power5-pmu.o \
+ power5+-pmu.o power6-pmu.o power7-pmu.o
obj-$(CONFIG_8XX_MINIMAL_FPEMU) += softemu8xx.o
diff --git a/arch/powerpc/kernel/time.c b/arch/powerpc/kernel/time.c
index 15391c2ab01..eae4511ceea 100644
--- a/arch/powerpc/kernel/time.c
+++ b/arch/powerpc/kernel/time.c
@@ -53,6 +53,7 @@
#include <linux/posix-timers.h>
#include <linux/irq.h>
#include <linux/delay.h>
+#include <linux/perf_counter.h>
#include <asm/io.h>
#include <asm/processor.h>
@@ -525,6 +526,26 @@ void __init iSeries_time_init_early(void)
}
#endif /* CONFIG_PPC_ISERIES */
+#if defined(CONFIG_PERF_COUNTERS) && defined(CONFIG_PPC32)
+DEFINE_PER_CPU(u8, perf_counter_pending);
+
+void set_perf_counter_pending(void)
+{
+ get_cpu_var(perf_counter_pending) = 1;
+ set_dec(1);
+ put_cpu_var(perf_counter_pending);
+}
+
+#define test_perf_counter_pending() __get_cpu_var(perf_counter_pending)
+#define clear_perf_counter_pending() __get_cpu_var(perf_counter_pending) = 0
+
+#else /* CONFIG_PERF_COUNTERS && CONFIG_PPC32 */
+
+#define test_perf_counter_pending() 0
+#define clear_perf_counter_pending()
+
+#endif /* CONFIG_PERF_COUNTERS && CONFIG_PPC32 */
+
/*
* For iSeries shared processors, we have to let the hypervisor
* set the hardware decrementer. We set a virtual decrementer
@@ -551,6 +572,10 @@ void timer_interrupt(struct pt_regs * regs)
set_dec(DECREMENTER_MAX);
#ifdef CONFIG_PPC32
+ if (test_perf_counter_pending()) {
+ clear_perf_counter_pending();
+ perf_counter_do_pending();
+ }
if (atomic_read(&ppc_n_lost_interrupts) != 0)
do_IRQ(regs);
#endif
diff --git a/arch/powerpc/platforms/Kconfig.cputype b/arch/powerpc/platforms/Kconfig.cputype
index cca6b4fc719..dd9f3ec5ee3 100644
--- a/arch/powerpc/platforms/Kconfig.cputype
+++ b/arch/powerpc/platforms/Kconfig.cputype
@@ -1,7 +1,7 @@
config PPC64
bool "64-bit kernel"
default n
- select HAVE_PERF_COUNTERS
+ select PPC_HAVE_PMU_SUPPORT
help
This option selects whether a 32-bit or a 64-bit kernel
will be built.
@@ -243,6 +243,15 @@ config VIRT_CPU_ACCOUNTING
If in doubt, say Y here.
+config PPC_HAVE_PMU_SUPPORT
+ bool
+
+config PPC_PERF_CTRS
+ def_bool y
+ depends on PERF_COUNTERS && PPC_HAVE_PMU_SUPPORT
+ help
+ This enables the powerpc-specific perf_counter back-end.
+
config SMP
depends on PPC_STD_MMU || FSL_BOOKE
bool "Symmetric multi-processing support"