diff options
| -rw-r--r-- | arch/mips/kernel/perf_event.c | 108 |
1 files changed, 107 insertions, 1 deletions
diff --git a/arch/mips/kernel/perf_event.c b/arch/mips/kernel/perf_event.c index eefdf60..95c833e 100644 --- a/arch/mips/kernel/perf_event.c +++ b/arch/mips/kernel/perf_event.c @@ -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; +} |