[PATCH v3 1/3] MIPS: Add user stack and registers to perf.

Ralf Baechle
2016-04-01T09:51:05Z

From: David Daney <david.daney@cavium.com>

This allows for extracting off-line stack traces from user-space code
in the perf tool.

[ralf@linux-mips.org: Add perf_get_regs_user() which is required after
88a7c26af8da (perf: >> Move task_pt_regs sampling into arch code).]

Signed-off-by: David Daney <david.daney@cavium.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
---
arch/mips/Kconfig | 2 +
arch/mips/include/uapi/asm/perf_regs.h | 41 +++++++++++++++++++++
arch/mips/kernel/Makefile | 2 +-
arch/mips/kernel/perf_regs.c | 67 ++++++++++++++++++++++++++++++++++
4 files changed, 111 insertions(+), 1 deletion(-)
create mode 100644 arch/mips/include/uapi/asm/perf_regs.h
create mode 100644 arch/mips/kernel/perf_regs.c

diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
index 35d92a1..6051f58 100644
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -11,6 +11,8 @@ config MIPS
select HAVE_IDE
select HAVE_OPROFILE
select HAVE_PERF_EVENTS
+ select HAVE_PERF_REGS
+ select HAVE_PERF_USER_STACK_DUMP
select PERF_USE_VMALLOC
select HAVE_ARCH_KGDB
select HAVE_ARCH_SECCOMP_FILTER
diff --git a/arch/mips/include/uapi/asm/perf_regs.h b/arch/mips/include/uapi/asm/perf_regs.h
new file mode 100644
index 0000000..9577af5
--- /dev/null
+++ b/arch/mips/include/uapi/asm/perf_regs.h
@@ -0,0 +1,41 @@
+#ifndef _ASM_MIPS_PERF_REGS_H
+#define _ASM_MIPS_PERF_REGS_H
+
+enum perf_event_mips_regs {
+ PERF_REG_MIPS_PC,
+ PERF_REG_MIPS_R1,
+ PERF_REG_MIPS_R2,
+ PERF_REG_MIPS_R3,
+ PERF_REG_MIPS_R4,
+ PERF_REG_MIPS_R5,
+ PERF_REG_MIPS_R6,
+ PERF_REG_MIPS_R7,
+ PERF_REG_MIPS_R8,
+ PERF_REG_MIPS_R9,
+ PERF_REG_MIPS_R10,
+ PERF_REG_MIPS_R11,
+ PERF_REG_MIPS_R12,
+ PERF_REG_MIPS_R13,
+ PERF_REG_MIPS_R14,
+ PERF_REG_MIPS_R15,
+ PERF_REG_MIPS_R16,
+ PERF_REG_MIPS_R17,
+ PERF_REG_MIPS_R18,
+ PERF_REG_MIPS_R19,
+ PERF_REG_MIPS_R20,
+ PERF_REG_MIPS_R21,
+ PERF_REG_MIPS_R22,
+ PERF_REG_MIPS_R23,
+ PERF_REG_MIPS_R24,
+ PERF_REG_MIPS_R25,
+ /*
+ * 26 and 27 are k0 and k1, they are always clobbered thus not
+ * stored.
+ */
+ PERF_REG_MIPS_R28,
+ PERF_REG_MIPS_R29,
+ PERF_REG_MIPS_R30,
+ PERF_REG_MIPS_R31,
+ PERF_REG_MIPS_MAX = PERF_REG_MIPS_R31 + 1,
+};
+#endif /* _ASM_MIPS_PERF_REGS_H */
diff --git a/arch/mips/kernel/Makefile b/arch/mips/kernel/Makefile
index 6a24628..1cdf1e9 100644
--- a/arch/mips/kernel/Makefile
+++ b/arch/mips/kernel/Makefile
@@ -97,7 +97,7 @@ CFLAGS_cpu-bugs64.o = $(shell if $(CC) $(KBUILD_CFLAGS) -Wa,-mdaddi -c -o /dev/n

obj-$(CONFIG_HAVE_STD_PC_SERIAL_PORT) += 8250-platform.o

-obj-$(CONFIG_PERF_EVENTS) += perf_event.o
+obj-$(CONFIG_PERF_EVENTS) += perf_event.o perf_regs.o
obj-$(CONFIG_HW_PERF_EVENTS) += perf_event_mipsxx.o

obj-$(CONFIG_JUMP_LABEL) += jump_label.o
diff --git a/arch/mips/kernel/perf_regs.c b/arch/mips/kernel/perf_regs.c
new file mode 100644
index 0000000..65bb25c
--- /dev/null
+++ b/arch/mips/kernel/perf_regs.c
@@ -0,0 +1,67 @@
+/*
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License. See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Some parts derived from x86 version of this file.
+ *
+ * Copyright (C) 2013 Cavium, Inc.
+ */
+
+#include <linux/perf_event.h>
+
+#include <asm/ptrace.h>
+
+#ifdef CONFIG_32BIT
+u64 perf_reg_abi(struct task_struct *tsk)
+{
+ return PERF_SAMPLE_REGS_ABI_32;
+}
+#else /* Must be CONFIG_64BIT */
+u64 perf_reg_abi(struct task_struct *tsk)
+{
+ if (test_tsk_thread_flag(tsk, TIF_32BIT_REGS))
+ return PERF_SAMPLE_REGS_ABI_32;
+ else
+ return PERF_SAMPLE_REGS_ABI_64;
+}
+#endif /* CONFIG_32BIT */
+
+int perf_reg_validate(u64 mask)
+{
+ if (!mask)
+ return -EINVAL;
+ if (mask & ~((1ull << PERF_REG_MIPS_MAX) - 1))
+ return -EINVAL;
+ return 0;
+}
+
+u64 perf_reg_value(struct pt_regs *regs, int idx)
+{
+ long v;
+
+ switch (idx) {
+ case PERF_REG_MIPS_PC:
+ v = regs->cp0_epc;
+ break;
+ case PERF_REG_MIPS_R1 ... PERF_REG_MIPS_R25:
+ v = regs->regs[idx - PERF_REG_MIPS_R1 + 1];
+ break;
+ case PERF_REG_MIPS_R28 ... PERF_REG_MIPS_R31:
+ v = regs->regs[idx - PERF_REG_MIPS_R28 + 28];
+ break;
+
+ default:
+ WARN_ON_ONCE(1);
+ return 0;
+ }
+
+ return (s64)v; /* Sign extend if 32-bit. */
+}
+
+void perf_get_regs_user(struct perf_regs *regs_user,
+ struct pt_regs *regs, struct pt_regs *regs_user_copy)
+{
+ regs_user->regs = task_pt_regs(current);
+ regs_user->abi = perf_reg_abi(current);
+}
--
2.5.5