From 105988c015943e77092a6568bc5fb7e386df6ccd Mon Sep 17 00:00:00 2001 From: Paul Mackerras Date: Wed, 17 Jun 2009 21:50:04 +1000 Subject: [PATCH] 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 Cc: Peter Zijlstra 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 --- arch/powerpc/Kconfig | 1 + arch/powerpc/include/asm/hw_irq.h | 5 ++++- arch/powerpc/include/asm/perf_counter.h | 10 ++++++++-- arch/powerpc/kernel/Makefile | 6 +++--- arch/powerpc/kernel/time.c | 25 +++++++++++++++++++++++++ arch/powerpc/platforms/Kconfig.cputype | 11 ++++++++++- 6 files changed, 51 insertions(+), 7 deletions(-) diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig index 9fb344d5a86a..bf6cedfa05db 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 10a642df014e..867ab8ed69b3 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 b398a84edced..2c2d9f643df0 100644 --- a/arch/powerpc/include/asm/perf_counter.h +++ b/arch/powerpc/include/asm/perf_counter.h @@ -57,10 +57,16 @@ 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 diff --git a/arch/powerpc/kernel/Makefile b/arch/powerpc/kernel/Makefile index 612b0c4dc26d..c5f93f061927 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 15391c2ab013..eae4511ceeac 100644 --- a/arch/powerpc/kernel/time.c +++ b/arch/powerpc/kernel/time.c @@ -53,6 +53,7 @@ #include #include #include +#include #include #include @@ -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 cca6b4fc719a..dd9f3ec5ee30 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" -- 2.39.5