v4.19.13 snapshot.
diff --git a/arch/mips/kernel/perf_event.c b/arch/mips/kernel/perf_event.c
new file mode 100644
index 0000000..f298eb2
--- /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
+}