This Patchset is for Kernel Module to Enable userspace access to PMU counters(ArmV8)
Signed-off-by: Yogesh Tillu <[email protected]> --- ARMv8_Module/Makefile | 8 ++++ ARMv8_Module/README | 1 + ARMv8_Module/enable_arm_pmu.c | 96 +++++++++++++++++++++++++++++++++++++++++ 3 files changed, 105 insertions(+) create mode 100644 ARMv8_Module/Makefile create mode 100644 ARMv8_Module/README create mode 100644 ARMv8_Module/enable_arm_pmu.c diff --git a/ARMv8_Module/Makefile b/ARMv8_Module/Makefile new file mode 100644 index 0000000..19a31ea --- /dev/null +++ b/ARMv8_Module/Makefile @@ -0,0 +1,8 @@ +obj-m := enable_arm_pmu.o +KDIR := /lib/modules/$(shell uname -r)/build +PWD := $(shell pwd) + +all: + $(MAKE) -C $(KDIR) SUBDIRS=$(PWD) modules +clean: + $(MAKE) -C $(KDIR) SUBDIRS=$(PWD) clean diff --git a/ARMv8_Module/README b/ARMv8_Module/README new file mode 100644 index 0000000..648456b --- /dev/null +++ b/ARMv8_Module/README @@ -0,0 +1 @@ +make ARCH=arm64 clean;make ARCH=arm64 CROSS_COMPILE=~/arm64-tc-14.06/bin/aarch64-linux-gnu- -C ~/work/lava_ci/juno/linux-linaro/workspace/builddir-3.16.0-linaro-juno/ SUBDIRS=`pwd` diff --git a/ARMv8_Module/enable_arm_pmu.c b/ARMv8_Module/enable_arm_pmu.c new file mode 100644 index 0000000..5c87b08 --- /dev/null +++ b/ARMv8_Module/enable_arm_pmu.c @@ -0,0 +1,96 @@ +/* + * Enable user-mode ARM performance counter access. + */ +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/smp.h> +/** -- Configuration stuff ------------------------------------------------- */ + +#define DRVR_NAME "enable_arm_pmu" + +#if !defined(__aarch64__) + #error Module can only be compiled on ARM 64 machines. +#endif + +/** -- Initialization & boilerplate ---------------------------------------- */ + +#define PERF_DEF_OPTS (1 | 16) +#define PERF_OPT_RESET_CYCLES (2 | 4) +#define PERF_OPT_DIV64 (8) +#define ARMV8_PMCR_MASK 0x3f +#define ARMV8_PMCR_E (1 << 0) /* Enable all counters */ +#define ARMV8_PMCR_P (1 << 1) /* Reset all counters */ +#define ARMV8_PMCR_C (1 << 2) /* Cycle counter reset */ +#define ARMV8_PMCR_D (1 << 3) /* CCNT counts every 64th cpu cycle */ +#define ARMV8_PMCR_X (1 << 4) /* Export to ETM */ +#define ARMV8_PMCR_DP (1 << 5) /* Disable CCNT if non-invasive debug*/ +#define ARMV8_PMCR_N_SHIFT 11 /* Number of counters supported */ +#define ARMV8_PMCR_N_MASK 0x1f + +#define ARMV8_PMUSERENR_EN_EL0 (1 << 0) /* EL0 access enable */ +#define ARMV8_PMUSERENR_CR (1 << 2) /* Cycle counter read enable */ +#define ARMV8_PMUSERENR_ER (1 << 3) /* Event counter read enable */ + +static inline u32 armv8pmu_pmcr_read(void) +{ + u64 val=0; + asm volatile("mrs %0, pmcr_el0" : "=r" (val)); + return (u32)val; +} +static inline void armv8pmu_pmcr_write(u32 val) +{ + val &= ARMV8_PMCR_MASK; + isb(); + asm volatile("msr pmcr_el0, %0" : : "r" ((u64)val)); +} + +static void +enable_cpu_counters(void* data) +{ + u32 val=0; +/* Enable user-mode access to counters. */ + asm volatile("msr pmuserenr_el0, %0" : : "r"((u64)ARMV8_PMUSERENR_EN_EL0|ARMV8_PMUSERENR_ER|ARMV8_PMUSERENR_CR)); +/* Initialize & Reset PMNC: C and P bits. */ + armv8pmu_pmcr_write(ARMV8_PMCR_P | ARMV8_PMCR_C); +/*G4.4.11 +PMINTENSET, Performance Monitors Interrupt Enable Set register */ +/*cycle counter overflow interrupt request is disabled */ + asm volatile("msr pmintenset_el1, %0" : : "r" ((u64)(0 << 31))); +/*start*/ + armv8pmu_pmcr_write(armv8pmu_pmcr_read() | ARMV8_PMCR_E); +} + +static void +disable_cpu_counters(void* data) +{ + u32 val=0; + printk(KERN_INFO "\n [" DRVR_NAME "] disabling user-mode PMU access on CPU #%d", + smp_processor_id()); + + /* Program PMU and disable all counters */ + armv8pmu_pmcr_write(armv8pmu_pmcr_read() |~ARMV8_PMCR_E); + /* disable user-mode access to counters. */ + asm volatile("msr pmuserenr_el0, %0" : : "r"((u64)0)); + +} + +static int __init +init(void) +{ + on_each_cpu(enable_cpu_counters, NULL, 1); + printk(KERN_INFO "[" DRVR_NAME "] initialized"); + return 0; +} + +static void __exit +fini(void) +{ + on_each_cpu(disable_cpu_counters, NULL, 1); + printk(KERN_INFO "[" DRVR_NAME "] unloaded"); +} + +MODULE_AUTHOR("Yogesh Tillu "); +MODULE_DESCRIPTION("Enables user-mode access to ARMv8 PMU counters"); +MODULE_VERSION("0:0.1-dev"); +module_init(init); +module_exit(fini); -- 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe linux-perf-users" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
