monitor.c

jos lab3代码

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

#include <inc/stdio.h>
#include <inc/string.h>
#include <inc/memlayout.h>
#include <inc/assert.h>
#include <inc/x86.h>

#include <kern/console.h>
#include <kern/monitor.h>
#include <kern/trap.h>
#include <kern/kdebug.h>

#define CMDBUF_SIZE	80	// enough for one VGA text line


struct Command {
	const char *name;
	const char *desc;
	// return -1 to force monitor to exit
	int (*func)(int argc, char** argv, struct Trapframe* tf);
};

static struct Command commands[] = {
	{ "help", "Display this list of commands", mon_help },
	{ "kerninfo", "Display information about the kernel", mon_kerninfo },
	{ "backtrace", "Display a listing of function call frames",mon_backtrace}
};
#define NCOMMANDS (sizeof(commands)/sizeof(commands[0]))

unsigned read_eip();

/***** Implementations of basic kernel monitor commands *****/

int
mon_help(int argc, char **argv, struct Trapframe *tf)
{
	int i;
	for (i = 0; i < NCOMMANDS; i++)
		cprintf("%s - %s\n", commands[i].name, commands[i].desc);
	return 0;
}

int
mon_kerninfo(int argc, char **argv, struct Trapframe *tf)
{
	extern char _start[], etext[], edata[], end[];

	cprintf("Special kernel symbols:\n");
	cprintf("  _start %08x (virt)  %08x (phys)\n", _start, _start - KERNBASE);
	cprintf("  etext  %08x (virt)  %08x (phys)\n", etext, etext - KERNBASE);
	cprintf("  edata  %08x (virt)  %08x (phys)\n", edata, edata - KERNBASE);
	cprintf("  end    %08x (virt)  %08x (phys)\n", end, end - KERNBASE);
	cprintf("Kernel executable memory footprint: %dKB\n",
		(end-_start+1023)/1024);
	return 0;
}

int
mon_backtrace(int argc, char **argv, struct Trapframe *tf)
{
// Your code here.
	// Your code here.
	uint32_t ebp=read_ebp();
	uint32_t eip=read_eip();
	//uint32_t esp=read_esp();
	struct Eipdebuginfo info;
	int i=0;
	char *name;
	uint32_t param1,param2,param3,param4,param5;
	cprintf("Stack backtrace:\n");
	while(ebp!=0)
	{
		__asm __volatile("movl 8(%1), %0" : "=r" (param1):"g"(ebp));
		__asm __volatile("movl 12(%1), %0" : "=r" (param2):"g"(ebp));
		__asm __volatile("movl 16(%1), %0" : "=r"(param3):"g"(ebp));
		__asm __volatile("movl 20(%1), %0" : "=r"(param4):"g"(ebp));
		__asm __volatile("movl 24(%1), %0" : "=r"(param5):"g"(ebp));
		debuginfo_eip(eip, &info);
		cprintf("%s:%d ",info.eip_file,info.eip_line);
		for(i=0;i<info.eip_fn_namelen;i++)
			cprintf("%c",*(info.eip_fn_name+i));
		//cprintf("+%x %d\n",eip-info.eip_fn_addr,info.eip_fn_narg);
		cprintf("+%x \n",eip-info.eip_fn_addr);
		cprintf("ebp %08x eip %08x args %08x %08x %08x %08x %08x\n",ebp,eip,param1,param2,param3,param4,param5);
		uint32_t tempebp;
	        __asm __volatile("movl (%1), %0" : "=r" (tempebp):"r"(ebp));
		__asm __volatile("movl 4(%1), %0" : "=r" (eip):"r"(ebp));
		ebp=tempebp;
	}
	return 0;
}



/***** Kernel monitor command interpreter *****/

#define WHITESPACE "\t\r\n "
#define MAXARGS 16

static int
runcmd(char *buf, struct Trapframe *tf)
{
	int argc;
	char *argv[MAXARGS];
	int i;

	// Parse the command buffer into whitespace-separated arguments
	argc = 0;
	argv[argc] = 0;
	while (1) {
		// gobble whitespace
		while (*buf && strchr(WHITESPACE, *buf))
			*buf++ = 0;
		if (*buf == 0)
			break;

		// save and scan past next arg
		if (argc == MAXARGS-1) {
			cprintf("Too many arguments (max %d)\n", MAXARGS);
			return 0;
		}
		argv[argc++] = buf;
		while (*buf && !strchr(WHITESPACE, *buf))
			buf++;
	}
	argv[argc] = 0;

	// Lookup and invoke the command
	if (argc == 0)
		return 0;
	for (i = 0; i < NCOMMANDS; i++) {
		if (strcmp(argv[0], commands[i].name) == 0)
			return commands[i].func(argc, argv, tf);
	}
	cprintf("Unknown command '%s'\n", argv[0]);
	return 0;
}

void
monitor(struct Trapframe *tf)
{
	char *buf;

	cprintf("Welcome to the JOS kernel monitor!\n");
	cprintf("Type 'help' for a list of commands.\n");

	if (tf != NULL)
		print_trapframe(tf);

	while (1) {
		buf = readline("K> ");
		if (buf != NULL)
			if (runcmd(buf, tf) < 0)
				break;
	}
}

// return EIP of caller.
// does not work if inlined.
// putting at the end of the file seems to prevent inlining.
unsigned
read_eip()
{
	uint32_t callerpc;
	__asm __volatile("movl 4(%%ebp), %0" : "=r" (callerpc));
	return callerpc;
}