1 files changed, 70 insertions, 0 deletions
diff --git a/arch/mips/kernel/perf_event.c b/arch/mips/kernel/perf_event.c
new file mode 100644
index 000000000..f298eb2ff
--- /dev/null
+++ b/arch/mips/kernel/perf_event.c
@@ -0,0 +1,70 @@
+/*
+ * 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 <linux/sched/task_stack.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
+}