LXR linux/arch/mips/kernel/perf

   1/*
   2 * Linux performance counter support for MIPS.
   3 *
   4 * Copyright (C) 2010 MIPS Technologies, Inc.
   5 * Author: Deng-Cheng Zhu
   6 *
   7 * This code is based on the implementation for ARM, which is in turn
   8 * based on the sparc64 perf event code and the x86 code. Performance
   9 * counter access is based on the MIPS Oprofile code. And the callchain
  10 * support references the code of MIPS stacktrace.c.
  11 *
  12 * This program is free software; you can redistribute it and/or modify
  13 * it under the terms of the GNU General Public License version 2 as
  14 * published by the Free Software Foundation.
  15 */
  16
  17#include <linux/perf_event.h>
  18
  19#include <asm/stacktrace.h>
  20
  21/* Callchain handling code. */
  22
  23/*
  24 * Leave userspace callchain empty for now. When we find a way to trace
  25 * the user stack callchains, we will add it here.
  26 */
  27
  28static void save_raw_perf_callchain(struct perf_callchain_entry *entry,
  29        unsigned long reg29)
  30{
  31        unsigned long *sp = (unsigned long *)reg29;
  32        unsigned long addr;
  33
  34        while (!kstack_end(sp)) {
  35                addr = *sp++;
  36                if (__kernel_text_address(addr)) {
  37                        perf_callchain_store(entry, addr);
  38                        if (entry->nr >= PERF_MAX_STACK_DEPTH)
  39                                break;
  40                }
  41        }
  42}
  43
  44void perf_callchain_kernel(struct perf_callchain_entry *entry,
  45                      struct pt_regs *regs)
  46{
  47        unsigned long sp = regs->regs[29];
  48#ifdef CONFIG_KALLSYMS
  49        unsigned long ra = regs->regs[31];
  50        unsigned long pc = regs->cp0_epc;
  51
  52        if (raw_show_trace || !__kernel_text_address(pc)) {
  53                unsigned long stack_page =
  54                        (unsigned long)task_stack_page(current);
  55                if (stack_page && sp >= stack_page &&
  56                    sp <= stack_page + THREAD_SIZE - 32)
  57                        save_raw_perf_callchain(entry, sp);
  58                return;
  59        }
  60        do {
  61                perf_callchain_store(entry, pc);
  62                if (entry->nr >= PERF_MAX_STACK_DEPTH)
  63                        break;
  64                pc = unwind_stack(current, &sp, pc, &ra);
  65        } while (pc);
  66#else
  67        save_raw_perf_callchain(entry, sp);
  68#endif
  69}
  70