From: Will Deacon will.deacon@arm.com
This patch implements the functions required for the perf registers API, allowing the perf tool to interface kernel register dumps with libunwind in order to provide userspace backtracing.
Signed-off-by: Will Deacon will.deacon@arm.com Cc: Jean Pihet jean.pihet@linaro.org --- arch/arm/Kconfig | 2 ++ arch/arm/include/uapi/asm/Kbuild | 1 + arch/arm/include/uapi/asm/perf_regs.h | 23 +++++++++++++++++++++++ arch/arm/kernel/Makefile | 1 + arch/arm/kernel/perf_regs.c | 30 ++++++++++++++++++++++++++++++ 5 files changed, 57 insertions(+) create mode 100644 arch/arm/include/uapi/asm/perf_regs.h create mode 100644 arch/arm/kernel/perf_regs.c
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index 3f7714d..5595888 100644 --- a/arch/arm/Kconfig +++ b/arch/arm/Kconfig @@ -51,6 +51,8 @@ config ARM select HAVE_MOD_ARCH_SPECIFIC if ARM_UNWIND select HAVE_OPROFILE if (HAVE_PERF_EVENTS) select HAVE_PERF_EVENTS + select HAVE_PERF_REGS + select HAVE_PERF_USER_STACK_DUMP select HAVE_REGS_AND_STACK_ACCESS_API select HAVE_SYSCALL_TRACEPOINTS select HAVE_UID16 diff --git a/arch/arm/include/uapi/asm/Kbuild b/arch/arm/include/uapi/asm/Kbuild index 18d76fd..70a1c9d 100644 --- a/arch/arm/include/uapi/asm/Kbuild +++ b/arch/arm/include/uapi/asm/Kbuild @@ -7,6 +7,7 @@ header-y += hwcap.h header-y += ioctls.h header-y += kvm_para.h header-y += mman.h +header-y += perf_regs.h header-y += posix_types.h header-y += ptrace.h header-y += setup.h diff --git a/arch/arm/include/uapi/asm/perf_regs.h b/arch/arm/include/uapi/asm/perf_regs.h new file mode 100644 index 0000000..ce59448 --- /dev/null +++ b/arch/arm/include/uapi/asm/perf_regs.h @@ -0,0 +1,23 @@ +#ifndef _ASM_ARM_PERF_REGS_H +#define _ASM_ARM_PERF_REGS_H + +enum perf_event_arm_regs { + PERF_REG_ARM_R0, + PERF_REG_ARM_R1, + PERF_REG_ARM_R2, + PERF_REG_ARM_R3, + PERF_REG_ARM_R4, + PERF_REG_ARM_R5, + PERF_REG_ARM_R6, + PERF_REG_ARM_R7, + PERF_REG_ARM_R8, + PERF_REG_ARM_R9, + PERF_REG_ARM_R10, + PERF_REG_ARM_FP, + PERF_REG_ARM_IP, + PERF_REG_ARM_SP, + PERF_REG_ARM_LR, + PERF_REG_ARM_PC, + PERF_REG_ARM_MAX, +}; +#endif /* _ASM_ARM_PERF_REGS_H */ diff --git a/arch/arm/kernel/Makefile b/arch/arm/kernel/Makefile index 5140df5f..9b818ca 100644 --- a/arch/arm/kernel/Makefile +++ b/arch/arm/kernel/Makefile @@ -78,6 +78,7 @@ obj-$(CONFIG_CPU_XSC3) += xscale-cp0.o obj-$(CONFIG_CPU_MOHAWK) += xscale-cp0.o obj-$(CONFIG_CPU_PJ4) += pj4-cp0.o obj-$(CONFIG_IWMMXT) += iwmmxt.o +obj-$(CONFIG_PERF_EVENTS) += perf_regs.o obj-$(CONFIG_HW_PERF_EVENTS) += perf_event.o perf_event_cpu.o AFLAGS_iwmmxt.o := -Wa,-mcpu=iwmmxt obj-$(CONFIG_ARM_CPU_TOPOLOGY) += topology.o diff --git a/arch/arm/kernel/perf_regs.c b/arch/arm/kernel/perf_regs.c new file mode 100644 index 0000000..6e4379c --- /dev/null +++ b/arch/arm/kernel/perf_regs.c @@ -0,0 +1,30 @@ + +#include <linux/errno.h> +#include <linux/kernel.h> +#include <linux/perf_event.h> +#include <linux/bug.h> +#include <asm/perf_regs.h> +#include <asm/ptrace.h> + +u64 perf_reg_value(struct pt_regs *regs, int idx) +{ + if (WARN_ON_ONCE((u32)idx >= PERF_REG_ARM_MAX)) + return 0; + + return regs->uregs[idx]; +} + +#define REG_RESERVED (~((1ULL << PERF_REG_ARM_MAX) - 1)) + +int perf_reg_validate(u64 mask) +{ + if (!mask || mask & REG_RESERVED) + return -EINVAL; + + return 0; +} + +u64 perf_reg_abi(struct task_struct *task) +{ + return PERF_SAMPLE_REGS_ABI_32; +}