ARM: perf: add support for perf registers API

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.

Cc: Jean Pihet <jean.pihet@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 1ad6fb6c094db415ec76a72a28356e75bdfd7d17..899d0c6ec2c516c06e585ec0de4e0df449c6ae7b 100644 (file)
--- 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 18d76fd5a2afb2bf27b91980f29c77094e6638c0..70a1c9da30ca39d4d4d79e8e73c3b8aec0d607e3 100644 (file)
--- 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 (file)
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 5140df5f23aa485214914a8dfbfdf31dc04a5691..9b818ca3610bce4d61cf149ec62c0ebd2de8673c 100644 (file)
--- 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 (file)
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;
+}