[PATCH 1/3] ARM: perf: add support for perf regs API

[Ard Biesheuvel]

On 4 September 2013 20:04, Jean Pihet <jean.pihet at linaro.org> wrote:
> From: Will Deacon <will.deacon at arm.com>
>
> This patch implements the functions required for the perf refs API,

'regs API' not 'refs API'


Regards,
Ard.


> allowing the perf tool to interface kernel register dumps with libunwind
> in order to provide userspace backtracing.
>
> Signed-off-by: Will Deacon <will.deacon at arm.com>
> ---
>  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 86bf7cb..642bc48 100644
> --- a/arch/arm/Kconfig
> +++ b/arch/arm/Kconfig
> @@ -49,6 +49,8 @@ config ARM
>         select HAVE_MEMBLOCK
>         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 86d10dd..c9e05f2 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;
> +}
> --
> 1.7.11.7
>
>
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