sh: perf events: Preliminary callchain support.

This implements preliminary support for perf callchains (at the moment
only the kernel side is implemented). The actual implementation itself is
just a simple wrapper around the unwinder API, which allows for callchain
generation with or without the dwarf unwinder.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>
This commit is contained in:
Paul Mundt 2009-11-05 16:20:09 +09:00
parent d1b261ef85
commit 830fafecc2
2 changed files with 99 additions and 1 deletions

View File

@ -39,7 +39,7 @@ obj-$(CONFIG_FUNCTION_GRAPH_TRACER) += ftrace.o
obj-$(CONFIG_DUMP_CODE) += disassemble.o
obj-$(CONFIG_HIBERNATION) += swsusp.o
obj-$(CONFIG_DWARF_UNWINDER) += dwarf.o
obj-$(CONFIG_PERF_EVENTS) += perf_event.o
obj-$(CONFIG_PERF_EVENTS) += perf_event.o perf_callchain.o
obj-$(CONFIG_GENERIC_CLOCKEVENTS_BROADCAST) += localtimer.o

View File

@ -0,0 +1,98 @@
/*
* Performance event callchain support - SuperH architecture code
*
* Copyright (C) 2009 Paul Mundt
*
* 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/kernel.h>
#include <linux/sched.h>
#include <linux/perf_event.h>
#include <linux/percpu.h>
#include <asm/unwinder.h>
#include <asm/ptrace.h>
static inline void callchain_store(struct perf_callchain_entry *entry, u64 ip)
{
if (entry->nr < PERF_MAX_STACK_DEPTH)
entry->ip[entry->nr++] = ip;
}
static void callchain_warning(void *data, char *msg)
{
}
static void
callchain_warning_symbol(void *data, char *msg, unsigned long symbol)
{
}
static int callchain_stack(void *data, char *name)
{
return 0;
}
static void callchain_address(void *data, unsigned long addr, int reliable)
{
struct perf_callchain_entry *entry = data;
if (reliable)
callchain_store(entry, addr);
}
static const struct stacktrace_ops callchain_ops = {
.warning = callchain_warning,
.warning_symbol = callchain_warning_symbol,
.stack = callchain_stack,
.address = callchain_address,
};
static void
perf_callchain_kernel(struct pt_regs *regs, struct perf_callchain_entry *entry)
{
callchain_store(entry, PERF_CONTEXT_KERNEL);
callchain_store(entry, regs->pc);
unwind_stack(NULL, regs, NULL, &callchain_ops, entry);
}
static void
perf_do_callchain(struct pt_regs *regs, struct perf_callchain_entry *entry)
{
int is_user;
if (!regs)
return;
is_user = user_mode(regs);
if (!current || current->pid == 0)
return;
if (is_user && current->state != TASK_RUNNING)
return;
/*
* Only the kernel side is implemented for now.
*/
if (!is_user)
perf_callchain_kernel(regs, entry);
}
/*
* No need for separate IRQ and NMI entries.
*/
static DEFINE_PER_CPU(struct perf_callchain_entry, callchain);
struct perf_callchain_entry *perf_callchain(struct pt_regs *regs)
{
struct perf_callchain_entry *entry = &__get_cpu_var(callchain);
entry->nr = 0;
perf_do_callchain(regs, entry);
return entry;
}