metag: OProfile support
authorJames Hogan <james.hogan@imgtec.com>
Fri, 15 Mar 2013 10:21:56 +0000 (10:21 +0000)
committerJames Hogan <james.hogan@imgtec.com>
Fri, 15 Mar 2013 13:21:05 +0000 (13:21 +0000)
Add OProfile support for metag, using the perf backend, and falling back
to generic timer based sampling if perf counter interrupt support is
disabled.

The oprofile code prepends "metag/" to the perf pmu name to give
"metag/meta2" which is more consistent with other oprofile arch names.

The backtrace code makes use of <asm/stacktrace.h> for kernel
backtracing, and a simple frame pointer walk for userland backtracing.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Robert Richter <rric@kernel.org>
Cc: oprofile-list@lists.sf.net
arch/metag/Kconfig
arch/metag/Makefile
arch/metag/oprofile/Makefile [new file with mode: 0644]
arch/metag/oprofile/backtrace.c [new file with mode: 0644]
arch/metag/oprofile/backtrace.h [new file with mode: 0644]
arch/metag/oprofile/common.c [new file with mode: 0644]

index afc8973d14883ee340ba9531c7c82b1585f9c9cd..b06b41861aaca2fa517f657d92d4ad6a8e572b89 100644 (file)
@@ -25,6 +25,7 @@ config METAG
        select HAVE_MEMBLOCK
        select HAVE_MEMBLOCK_NODE_MAP
        select HAVE_MOD_ARCH_SPECIFIC
+       select HAVE_OPROFILE
        select HAVE_PERF_EVENTS
        select HAVE_SYSCALL_TRACEPOINTS
        select IRQ_DOMAIN
@@ -209,6 +210,9 @@ config METAG_PERFCOUNTER_IRQS
          When disabled, Performance Counters information will be collected
          based on Timer Interrupt.
 
+config HW_PERF_EVENTS
+       def_bool METAG_PERFCOUNTER_IRQS && PERF_EVENTS
+
 config METAG_DA
        bool "DA support"
        help
index 81bd6a1c7483b665100692ff7ddfaf7c0ee93d37..b566116b171b6564756d139eb179d3bcc0186fc2 100644 (file)
@@ -49,6 +49,8 @@ core-y                                        += arch/metag/mm/
 libs-y                                 += arch/metag/lib/
 libs-y                                 += arch/metag/tbx/
 
+drivers-$(CONFIG_OPROFILE)             += arch/metag/oprofile/
+
 boot                                   := arch/metag/boot
 
 boot_targets                           += uImage
diff --git a/arch/metag/oprofile/Makefile b/arch/metag/oprofile/Makefile
new file mode 100644 (file)
index 0000000..c9639d4
--- /dev/null
@@ -0,0 +1,17 @@
+obj-$(CONFIG_OPROFILE) += oprofile.o
+
+oprofile-core-y        += buffer_sync.o
+oprofile-core-y        += cpu_buffer.o
+oprofile-core-y        += event_buffer.o
+oprofile-core-y        += oprof.o
+oprofile-core-y        += oprofile_files.o
+oprofile-core-y        += oprofile_stats.o
+oprofile-core-y        += oprofilefs.o
+oprofile-core-y        += timer_int.o
+oprofile-core-$(CONFIG_HW_PERF_EVENTS) += oprofile_perf.o
+
+oprofile-y     += backtrace.o
+oprofile-y     += common.o
+oprofile-y     += $(addprefix ../../../drivers/oprofile/,$(oprofile-core-y))
+
+ccflags-y      += -Werror
diff --git a/arch/metag/oprofile/backtrace.c b/arch/metag/oprofile/backtrace.c
new file mode 100644 (file)
index 0000000..7cc3f37
--- /dev/null
@@ -0,0 +1,63 @@
+/*
+ * Copyright (C) 2010-2013 Imagination Technologies Ltd.
+ *
+ * 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.
+ */
+
+#include <linux/oprofile.h>
+#include <linux/uaccess.h>
+#include <asm/processor.h>
+#include <asm/stacktrace.h>
+
+#include "backtrace.h"
+
+static void user_backtrace_fp(unsigned long __user *fp, unsigned int depth)
+{
+       while (depth-- && access_ok(VERIFY_READ, fp, 8)) {
+               unsigned long addr;
+               unsigned long __user *fpnew;
+               if (__copy_from_user_inatomic(&addr, fp + 1, sizeof(addr)))
+                       break;
+               addr -= 4;
+
+               oprofile_add_trace(addr);
+
+               /* stack grows up, so frame pointers must decrease */
+               if (__copy_from_user_inatomic(&fpnew, fp + 0, sizeof(fpnew)))
+                       break;
+               if (fpnew >= fp)
+                       break;
+               fp = fpnew;
+       }
+}
+
+static int kernel_backtrace_frame(struct stackframe *frame, void *data)
+{
+       unsigned int *depth = data;
+
+       oprofile_add_trace(frame->pc);
+
+       /* decrement depth and stop if we reach 0 */
+       if ((*depth)-- == 0)
+               return 1;
+
+       /* otherwise onto the next frame */
+       return 0;
+}
+
+void metag_backtrace(struct pt_regs * const regs, unsigned int depth)
+{
+       if (user_mode(regs)) {
+               unsigned long *fp = (unsigned long *)regs->ctx.AX[1].U0;
+               user_backtrace_fp((unsigned long __user __force *)fp, depth);
+       } else {
+               struct stackframe frame;
+               frame.fp = regs->ctx.AX[1].U0;          /* A0FrP */
+               frame.sp = user_stack_pointer(regs);    /* A0StP */
+               frame.lr = 0;                           /* from stack */
+               frame.pc = regs->ctx.CurrPC;            /* PC */
+               walk_stackframe(&frame, &kernel_backtrace_frame, &depth);
+       }
+}
diff --git a/arch/metag/oprofile/backtrace.h b/arch/metag/oprofile/backtrace.h
new file mode 100644 (file)
index 0000000..c0fcc42
--- /dev/null
@@ -0,0 +1,6 @@
+#ifndef _METAG_OPROFILE_BACKTRACE_H
+#define _METAG_OPROFILE_BACKTRACE_H
+
+void metag_backtrace(struct pt_regs * const regs, unsigned int depth);
+
+#endif
diff --git a/arch/metag/oprofile/common.c b/arch/metag/oprofile/common.c
new file mode 100644 (file)
index 0000000..ba26152
--- /dev/null
@@ -0,0 +1,66 @@
+/*
+ * arch/metag/oprofile/common.c
+ *
+ * Copyright (C) 2013 Imagination Technologies Ltd.
+ *
+ * Based on arch/sh/oprofile/common.c:
+ *
+ * Copyright (C) 2003 - 2010  Paul Mundt
+ *
+ * Based on arch/mips/oprofile/common.c:
+ *
+ *     Copyright (C) 2004, 2005 Ralf Baechle
+ *     Copyright (C) 2005 MIPS Technologies, Inc.
+ *
+ * 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.
+ */
+#include <linux/errno.h>
+#include <linux/init.h>
+#include <linux/oprofile.h>
+#include <linux/perf_event.h>
+#include <linux/slab.h>
+
+#include "backtrace.h"
+
+#ifdef CONFIG_HW_PERF_EVENTS
+/*
+ * This will need to be reworked when multiple PMUs are supported.
+ */
+static char *metag_pmu_op_name;
+
+char *op_name_from_perf_id(void)
+{
+       return metag_pmu_op_name;
+}
+
+int __init oprofile_arch_init(struct oprofile_operations *ops)
+{
+       ops->backtrace = metag_backtrace;
+
+       if (perf_num_counters() == 0)
+               return -ENODEV;
+
+       metag_pmu_op_name = kasprintf(GFP_KERNEL, "metag/%s",
+                                     perf_pmu_name());
+       if (unlikely(!metag_pmu_op_name))
+               return -ENOMEM;
+
+       return oprofile_perf_init(ops);
+}
+
+void oprofile_arch_exit(void)
+{
+       oprofile_perf_exit();
+       kfree(metag_pmu_op_name);
+}
+#else
+int __init oprofile_arch_init(struct oprofile_operations *ops)
+{
+       ops->backtrace = metag_backtrace;
+       /* fall back to timer interrupt PC sampling */
+       return -ENODEV;
+}
+void oprofile_arch_exit(void) {}
+#endif /* CONFIG_HW_PERF_EVENTS */