Commit 830fafec authored by Paul Mundt's avatar Paul Mundt
Browse files

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: default avatarPaul Mundt <lethal@linux-sh.org>
parent d1b261ef

arch/sh/kernel/Makefile

+1 −1
Original line number Diff line number Diff line
@@ -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

arch/sh/kernel/perf_callchain.c

0 → 100644
+98 −0
Original line number Diff line number Diff line 
/*

 * 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;

}