tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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>
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arch/sh/kernel/Makefile
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arch/sh/kernel/Makefile
···
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obj-$(CONFIG_DUMP_CODE) += disassemble.o
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obj-$(CONFIG_HIBERNATION) += swsusp.o
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obj-$(CONFIG_DWARF_UNWINDER) += dwarf.o
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obj-$(CONFIG_PERF_EVENTS) += perf_event.o
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obj-$(CONFIG_PERF_EVENTS) += perf_event.o perf_callchain.o
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obj-$(CONFIG_GENERIC_CLOCKEVENTS_BROADCAST) += localtimer.o
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arch/sh/kernel/perf_callchain.c
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arch/sh/kernel/perf_callchain.c
···
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/*
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* Performance event callchain support - SuperH architecture code
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*
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* Copyright (C) 2009 Paul Mundt
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*
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* This file is subject to the terms and conditions of the GNU General Public
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* License. See the file "COPYING" in the main directory of this archive
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* for more details.
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*/
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#include <linux/kernel.h>
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#include <linux/sched.h>
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#include <linux/perf_event.h>
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#include <linux/percpu.h>
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#include <asm/unwinder.h>
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#include <asm/ptrace.h>
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static inline void callchain_store(struct perf_callchain_entry *entry, u64 ip)
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{
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if (entry->nr < PERF_MAX_STACK_DEPTH)
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entry->ip[entry->nr++] = ip;
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}
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static void callchain_warning(void *data, char *msg)
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{
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}
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static void
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callchain_warning_symbol(void *data, char *msg, unsigned long symbol)
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{
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}
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static int callchain_stack(void *data, char *name)
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{
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return 0;
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}
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static void callchain_address(void *data, unsigned long addr, int reliable)
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{
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struct perf_callchain_entry *entry = data;
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if (reliable)
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callchain_store(entry, addr);
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}
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static const struct stacktrace_ops callchain_ops = {
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.warning = callchain_warning,
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.warning_symbol = callchain_warning_symbol,
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.stack = callchain_stack,
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.address = callchain_address,
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};
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static void
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perf_callchain_kernel(struct pt_regs *regs, struct perf_callchain_entry *entry)
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{
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callchain_store(entry, PERF_CONTEXT_KERNEL);
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callchain_store(entry, regs->pc);
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unwind_stack(NULL, regs, NULL, &callchain_ops, entry);
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}
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static void
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perf_do_callchain(struct pt_regs *regs, struct perf_callchain_entry *entry)
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{
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int is_user;
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if (!regs)
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return;
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is_user = user_mode(regs);
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if (!current || current->pid == 0)
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return;
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if (is_user && current->state != TASK_RUNNING)
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return;
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/*
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* Only the kernel side is implemented for now.
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*/
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if (!is_user)
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perf_callchain_kernel(regs, entry);
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}
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/*
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* No need for separate IRQ and NMI entries.
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*/
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static DEFINE_PER_CPU(struct perf_callchain_entry, callchain);
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struct perf_callchain_entry *perf_callchain(struct pt_regs *regs)
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{
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struct perf_callchain_entry *entry = &__get_cpu_var(callchain);
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entry->nr = 0;
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perf_do_callchain(regs, entry);
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return entry;
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}