// SPDX-License-Identifier: GPL-2.0-only/* * 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. */ #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}