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MIPS: Perf-events: Add callchain support

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Adds callchain support for MIPS Perf-events. For more info on this feature,
please refer to tools/perf/Documentation/perf-report.txt and
tools/perf/design.txt.

Currently userspace callchain data is not recorded, because we do not have
a safe way to do this.

Signed-off-by: Deng-Cheng Zhu <dengcheng.zhu@gmail.com>
Acked-by: David Daney <ddaney@caviumnetworks.com>
To: linux-mips@linux-mips.org
Cc: a.p.zijlstra@chello.nl
Cc: paulus@samba.org
Cc: mingo@elte.hu
Cc: acme@redhat.com
Cc: jamie.iles@picochip.com
Cc: matt@console-pimps.org
Patchwork: https://patchwork.linux-mips.org/patch/1690/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
This commit is contained in:
Deng-Cheng Zhu 2010-10-12 19:37:23 +08:00 committed by Ralf Baechle
parent 14f7001284
commit 7e788d967c
1 changed files with 107 additions and 1 deletions
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108
arch/mips/kernel/perf_event.c
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@ -6,7 +6,8 @@
*
* This code is based on the implementation for ARM, which is in turn
* based on the sparc64 perf event code and the x86 code. Performance
* counter access is based on the MIPS Oprofile code.
* counter access is based on the MIPS Oprofile code. And the callchain
* support references the code of MIPS stacktrace.c.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
@ -486,3 +487,108 @@ handle_associated_event(struct cpu_hw_events *cpuc,
if (perf_event_overflow(event, 0, data, regs))
mipspmu->disable_event(idx);
}
/* Callchain handling code. */
static inline void
callchain_store(struct perf_callchain_entry *entry,
u64 ip)
{
if (entry->nr < PERF_MAX_STACK_DEPTH)
entry->ip[entry->nr++] = ip;
}
/*
* Leave userspace callchain empty for now. When we find a way to trace
* the user stack callchains, we add here.
*/
static void
perf_callchain_user(struct pt_regs *regs,
struct perf_callchain_entry *entry)
{
}
static void save_raw_perf_callchain(struct perf_callchain_entry *entry,
unsigned long reg29)
{
unsigned long *sp = (unsigned long *)reg29;
unsigned long addr;
while (!kstack_end(sp)) {
addr = *sp++;
if (__kernel_text_address(addr)) {
callchain_store(entry, addr);
if (entry->nr >= PERF_MAX_STACK_DEPTH)
break;
}
}
}
static void
perf_callchain_kernel(struct pt_regs *regs,
struct perf_callchain_entry *entry)
{
unsigned long sp = regs->regs[29];
#ifdef CONFIG_KALLSYMS
unsigned long ra = regs->regs[31];
unsigned long pc = regs->cp0_epc;
callchain_store(entry, PERF_CONTEXT_KERNEL);
if (raw_show_trace || !__kernel_text_address(pc)) {
unsigned long stack_page =
(unsigned long)task_stack_page(current);
if (stack_page && sp >= stack_page &&
sp <= stack_page + THREAD_SIZE - 32)
save_raw_perf_callchain(entry, sp);
return;
}
do {
callchain_store(entry, pc);
if (entry->nr >= PERF_MAX_STACK_DEPTH)
break;
pc = unwind_stack(current, &sp, pc, &ra);
} while (pc);
#else
callchain_store(entry, PERF_CONTEXT_KERNEL);
save_raw_perf_callchain(entry, sp);
#endif
}
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)
return;
if (is_user && current->state != TASK_RUNNING)
return;
if (!is_user) {
perf_callchain_kernel(regs, entry);
if (current->mm)
regs = task_pt_regs(current);
else
regs = NULL;
}
if (regs)
perf_callchain_user(regs, entry);
}
static DEFINE_PER_CPU(struct perf_callchain_entry, pmc_irq_entry);
struct perf_callchain_entry *
perf_callchain(struct pt_regs *regs)
{
struct perf_callchain_entry *entry = &__get_cpu_var(pmc_irq_entry);
entry->nr = 0;
perf_do_callchain(regs, entry);
return entry;
}