mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-12-04 13:36:47 +07:00
3b1fff0803
We will use it to count how many addresses are in the entry->ip[] array,
excluding PERF_CONTEXT_{KERNEL,USER,etc} entries, so that we can really
return the number of entries specified by the user via the relevant
sysctl, kernel.perf_event_max_contexts, or via the per event
perf_event_attr.sample_max_stack knob.
This way we keep the perf_sample->ip_callchain->nr meaning, that is the
number of entries, be it real addresses or PERF_CONTEXT_ entries, while
honouring the max_stack knobs, i.e. the end result will be max_stack
entries if we have at least that many entries in a given stack trace.
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/n/tip-s8teto51tdqvlfhefndtat9r@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
70 lines
1.8 KiB
C
70 lines
1.8 KiB
C
/*
|
|
* Linux performance counter support for MIPS.
|
|
*
|
|
* Copyright (C) 2010 MIPS Technologies, Inc.
|
|
* Author: Deng-Cheng Zhu
|
|
*
|
|
* 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. 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
|
|
* published by the Free Software Foundation.
|
|
*/
|
|
|
|
#include <linux/perf_event.h>
|
|
|
|
#include <asm/stacktrace.h>
|
|
|
|
/* Callchain handling code. */
|
|
|
|
/*
|
|
* Leave userspace callchain empty for now. When we find a way to trace
|
|
* the user stack callchains, we will add it here.
|
|
*/
|
|
|
|
static void save_raw_perf_callchain(struct perf_callchain_entry_ctx *entry,
|
|
unsigned long reg29)
|
|
{
|
|
unsigned long *sp = (unsigned long *)reg29;
|
|
unsigned long addr;
|
|
|
|
while (!kstack_end(sp)) {
|
|
addr = *sp++;
|
|
if (__kernel_text_address(addr)) {
|
|
perf_callchain_store(entry, addr);
|
|
if (entry->nr >= entry->max_stack)
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
void perf_callchain_kernel(struct perf_callchain_entry_ctx *entry,
|
|
struct pt_regs *regs)
|
|
{
|
|
unsigned long sp = regs->regs[29];
|
|
#ifdef CONFIG_KALLSYMS
|
|
unsigned long ra = regs->regs[31];
|
|
unsigned long pc = regs->cp0_epc;
|
|
|
|
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 {
|
|
perf_callchain_store(entry, pc);
|
|
if (entry->nr >= entry->max_stack)
|
|
break;
|
|
pc = unwind_stack(current, &sp, pc, &ra);
|
|
} while (pc);
|
|
#else
|
|
save_raw_perf_callchain(entry, sp);
|
|
#endif
|
|
}
|