/*
 * Copyright (c) 2020 Institute of Parallel And Distributed Systems (IPADS), Shanghai Jiao Tong University (SJTU)
 * OS-Lab-2020 (i.e., ChCore) is licensed under the Mulan PSL v1.
 * You can use this software according to the terms and conditions of the Mulan PSL v1.
 * You may obtain a copy of Mulan PSL v1 at:
 *   http://license.coscl.org.cn/MulanPSL
 *   THIS SOFTWARE IS PROVIDED ON AN "AS IS" BASIS, WITHOUT WARRANTIES OF ANY KIND, EITHER EXPRESS OR
 *   IMPLIED, INCLUDING BUT NOT LIMITED TO NON-INFRINGEMENT, MERCHANTABILITY OR FIT FOR A PARTICULAR
 *   PURPOSE.
 *   See the Mulan PSL v1 for more details.
 */

// Simple command-line kernel monitor useful for
// controlling the kernel and exploring the system interactively.

#include <common/printk.h>
#include <common/types.h>
#include <common/machine.h>

extern char kernel_stack[PLAT_CPU_NUM][KERNEL_STACK_SIZE];

static inline __attribute__ ((always_inline))
u64 read_fp()
{
	u64 fp;
	__asm __volatile("mov %0, x29":"=r"(fp));
	return fp;
}

__attribute__ ((optimize("O1")))
int stack_backtrace()
{
	printk("Stack backtrace:\n");

	// Your code here.
	u64 *fp, *preFp;
	fp = (u64 *) read_fp();
	// until stack end
	while (true) {
		preFp = (u64 *) *fp;
		// entry frame
		if (preFp == 0)
			break;
		printk("LR %lx FP %lx Args", *(preFp + 1), preFp);
		for (int i = 0; i < 5; i++) {
			printk(" %lx", *(fp + 2 + i));
		}
		printk("\n");
		fp = preFp;
	}

	return 0;
}