xmon.c

linux-2.6.15.6

/*
 * Routines providing a simple monitor for use on the PowerMac.
 *
 * Copyright (C) 1996 Paul Mackerras.
 */
#include <linux/config.h>
#include <linux/errno.h>
#include <linux/sched.h>
#include <linux/smp.h>
#include <linux/interrupt.h>
#include <linux/bitops.h>
#include <linux/kallsyms.h>
#include <asm/ptrace.h>
#include <asm/string.h>
#include <asm/prom.h>
#include <asm/bootx.h>
#include <asm/machdep.h>
#include <asm/xmon.h>
#ifdef CONFIG_PMAC_BACKLIGHT
#include <asm/backlight.h>
#endif
#include "nonstdio.h"
#include "privinst.h"

#define scanhex	xmon_scanhex
#define skipbl	xmon_skipbl

#ifdef CONFIG_SMP
static unsigned long cpus_in_xmon = 0;
static unsigned long got_xmon = 0;
static volatile int take_xmon = -1;
#endif /* CONFIG_SMP */

static unsigned adrs;
static int size = 1;
static unsigned ndump = 64;
static unsigned nidump = 16;
static unsigned ncsum = 4096;
static int termch;

static u_int bus_error_jmp[100];
#define setjmp xmon_setjmp
#define longjmp xmon_longjmp

/* Breakpoint stuff */
struct bpt {
	unsigned address;
	unsigned instr;
	unsigned count;
	unsigned char enabled;
};

#define NBPTS	16
static struct bpt bpts[NBPTS];
static struct bpt dabr;
static struct bpt iabr;
static unsigned bpinstr = 0x7fe00008;	/* trap */

/* Prototypes */
extern void (*debugger_fault_handler)(struct pt_regs *);
static int cmds(struct pt_regs *);
static int mread(unsigned, void *, int);
static int mwrite(unsigned, void *, int);
static void handle_fault(struct pt_regs *);
static void byterev(unsigned char *, int);
static void memex(void);
static int bsesc(void);
static void dump(void);
static void prdump(unsigned, int);
#ifdef __MWERKS__
static void prndump(unsigned, int);
static int nvreadb(unsigned);
#endif
static int ppc_inst_dump(unsigned, int);
void print_address(unsigned);
static int getsp(void);
static void dump_hash_table(void);
static void backtrace(struct pt_regs *);
static void excprint(struct pt_regs *);
static void prregs(struct pt_regs *);
static void memops(int);
static void memlocate(void);
static void memzcan(void);
static void memdiffs(unsigned char *, unsigned char *, unsigned, unsigned);
int skipbl(void);
int scanhex(unsigned *valp);
static void scannl(void);
static int hexdigit(int);
void getstring(char *, int);
static void flush_input(void);
static int inchar(void);
static void take_input(char *);
/* static void openforth(void); */
static unsigned read_spr(int);
static void write_spr(int, unsigned);
static void super_regs(void);
static void symbol_lookup(void);
static void remove_bpts(void);
static void insert_bpts(void);
static struct bpt *at_breakpoint(unsigned pc);
static void bpt_cmds(void);
static void cacheflush(void);
#ifdef CONFIG_SMP
static void cpu_cmd(void);
#endif /* CONFIG_SMP */
static void csum(void);
#ifdef CONFIG_BOOTX_TEXT
static void vidcmds(void);
#endif
static void bootcmds(void);
static void proccall(void);
static void printtime(void);

extern int print_insn_big_powerpc(FILE *, unsigned long, unsigned);
extern void printf(const char *fmt, ...);
extern int putchar(int ch);
extern int setjmp(u_int *);
extern void longjmp(u_int *, int);

extern void xmon_enter(void);
extern void xmon_leave(void);

static unsigned start_tb[NR_CPUS][2];
static unsigned stop_tb[NR_CPUS][2];

#define GETWORD(v)	(((v)[0] << 24) + ((v)[1] << 16) + ((v)[2] << 8) + (v)[3])

#define isxdigit(c)	(('0' <= (c) && (c) <= '9') \
			 || ('a' <= (c) && (c) <= 'f') \
			 || ('A' <= (c) && (c) <= 'F'))
#define isalnum(c)	(('0' <= (c) && (c) <= '9') \
			 || ('a' <= (c) && (c) <= 'z') \
			 || ('A' <= (c) && (c) <= 'Z'))
#define isspace(c)	(c == ' ' || c == '\t' || c == 10 || c == 13 || c == 0)

static char *help_string = "\
Commands:\n\
  d	dump bytes\n\
  di	dump instructions\n\
  df	dump float values\n\
  dd	dump double values\n\
  e	print exception information\n\
  h	dump hash table\n\
  m	examine/change memory\n\
  mm	move a block of memory\n\
  ms	set a block of memory\n\
  md	compare two blocks of memory\n\
  r	print registers\n\
  S	print special registers\n\
  t	print backtrace\n\
  la	lookup address\n\
  ls	lookup symbol\n\
  C	checksum\n\
  p	call function with arguments\n\
  T	print time\n\
  x	exit monitor\n\
  zr    reboot\n\
  zh    halt\n\
";

static int xmon_trace[NR_CPUS];
#define SSTEP	1		/* stepping because of 's' command */
#define BRSTEP	2		/* stepping over breakpoint */

static struct pt_regs *xmon_regs[NR_CPUS];

extern inline void sync(void)
{
	asm volatile("sync; isync");
}

extern inline void __delay(unsigned int loops)
{
	if (loops != 0)
		__asm__ __volatile__("mtctr %0; 1: bdnz 1b" : :
				     "r" (loops) : "ctr");
}

/* Print an address in numeric and symbolic form (if possible) */
static void xmon_print_symbol(unsigned long address, const char *mid,
			      const char *after)
{
	char *modname;
	const char *name = NULL;
	unsigned long offset, size;
	static char tmpstr[128];

	printf("%.8lx", address);
	if (setjmp(bus_error_jmp) == 0) {
		debugger_fault_handler = handle_fault;
		sync();
		name = kallsyms_lookup(address, &size, &offset, &modname,
				       tmpstr);
		sync();
		/* wait a little while to see if we get a machine check */
		__delay(200);
	}
	debugger_fault_handler = NULL;

	if (name) {
		printf("%s%s+%#lx/%#lx", mid, name, offset, size);
		if (modname)
			printf(" [%s]", modname);
	}
	printf("%s", after);
}

static void get_tb(unsigned *p)
{
	unsigned hi, lo, hiagain;

	if ((get_pvr() >> 16) == 1)
		return;

	do {
		asm volatile("mftbu %0; mftb %1; mftbu %2"
			     : "=r" (hi), "=r" (lo), "=r" (hiagain));
	} while (hi != hiagain);
	p[0] = hi;
	p[1] = lo;
}

int xmon(struct pt_regs *excp)
{
	struct pt_regs regs;
	int msr, cmd;

	get_tb(stop_tb[smp_processor_id()]);
	if (excp == NULL) {
		asm volatile ("stw	0,0(%0)\n\
			lwz	0,0(1)\n\
			stw	0,4(%0)\n\
			stmw	2,8(%0)" : : "b" (&regs));
		regs.nip = regs.link = ((unsigned long *)regs.gpr[1])[1];
		regs.msr = get_msr();
		regs.ctr = get_ctr();
		regs.xer = get_xer();
		regs.ccr = get_cr();
		regs.trap = 0;
		excp = &regs;
	}

	msr = get_msr();
	set_msr(msr & ~0x8000);	/* disable interrupts */
	xmon_regs[smp_processor_id()] = excp;
	xmon_enter();
	excprint(excp);
#ifdef CONFIG_SMP
	if (test_and_set_bit(smp_processor_id(), &cpus_in_xmon))
		for (;;)
			;
	while (test_and_set_bit(0, &got_xmon)) {
		if (take_xmon == smp_processor_id()) {
			take_xmon = -1;
			break;
		}
	}
	/*
	 * XXX: breakpoints are removed while any cpu is in xmon
	 */
#endif /* CONFIG_SMP */
	remove_bpts();
#ifdef CONFIG_PMAC_BACKLIGHT
	if( setjmp(bus_error_jmp) == 0 ) {
		debugger_fault_handler = handle_fault;
		sync();
		set_backlight_enable(1);
		set_backlight_level(BACKLIGHT_MAX);
		sync();
	}
	debugger_fault_handler = NULL;
#endif	/* CONFIG_PMAC_BACKLIGHT */
	cmd = cmds(excp);
	if (cmd == 's') {
		xmon_trace[smp_processor_id()] = SSTEP;
		excp->msr |= 0x400;
	} else if (at_breakpoint(excp->nip)) {
		xmon_trace[smp_processor_id()] = BRSTEP;
		excp->msr |= 0x400;
	} else {
		xmon_trace[smp_processor_id()] = 0;
		insert_bpts();
	}
	xmon_leave();
	xmon_regs[smp_processor_id()] = NULL;
#ifdef CONFIG_SMP
	clear_bit(0, &got_xmon);
	clear_bit(smp_processor_id(), &cpus_in_xmon);
#endif /* CONFIG_SMP */
	set_msr(msr);		/* restore interrupt enable */
	get_tb(start_tb[smp_processor_id()]);

	return cmd != 'X';
}

irqreturn_t
xmon_irq(int irq, void *d, struct pt_regs *regs)
{
	unsigned long flags;
	local_irq_save(flags);
	printf("Keyboard interrupt\n");
	xmon(regs);
	local_irq_restore(flags);
	return IRQ_HANDLED;
}

int
xmon_bpt(struct pt_regs *regs)
{
	struct bpt *bp;

	bp = at_breakpoint(regs->nip);
	if (!bp)
		return 0;
	if (bp->count) {
		--bp->count;
		remove_bpts();
		excprint(regs);
		xmon_trace[smp_processor_id()] = BRSTEP;
		regs->msr |= 0x400;
	} else {
		xmon(regs);
	}
	return 1;
}

int
xmon_sstep(struct pt_regs *regs)
{
	if (!xmon_trace[smp_processor_id()])
		return 0;
	if (xmon_trace[smp_processor_id()] == BRSTEP) {
		xmon_trace[smp_processor_id()] = 0;
		insert_bpts();
	} else {
		xmon(regs);
	}
	return 1;
}

int
xmon_dabr_match(struct pt_regs *regs)
{
	if (dabr.enabled && dabr.count) {
		--dabr.count;
		remove_bpts();
		excprint(regs);
		xmon_trace[smp_processor_id()] = BRSTEP;
		regs->msr |= 0x400;
	} else {
		dabr.instr = regs->nip;
		xmon(regs);
	}
	return 1;
}

int
xmon_iabr_match(struct pt_regs *regs)
{
	if (iabr.enabled && iabr.count) {
		--iabr.count;
		remove_bpts();
		excprint(regs);
		xmon_trace[smp_processor_id()] = BRSTEP;
		regs->msr |= 0x400;
	} else {
		xmon(regs);
	}
	return 1;
}

static struct bpt *
at_breakpoint(unsigned pc)
{
	int i;
	struct bpt *bp;

	if (dabr.enabled && pc == dabr.instr)
		return &dabr;
	if (iabr.enabled && pc == iabr.address)
		return &iabr;
	bp = bpts;
	for (i = 0; i < NBPTS; ++i, ++bp)
		if (bp->enabled && pc == bp->address)
			return bp;
	return NULL;
}

static void
insert_bpts(void)
{
	int i;
	struct bpt *bp;

	bp = bpts;
	for (i = 0; i < NBPTS; ++i, ++bp) {
		if (!bp->enabled)
			continue;
		if (mread(bp->address, &bp->instr, 4) != 4
		    || mwrite(bp->address, &bpinstr, 4) != 4) {
			printf("Couldn't insert breakpoint at %x, disabling\n",
			       bp->address);
			bp->enabled = 0;
		}
		store_inst((void *) bp->address);
	}
#if !defined(CONFIG_8xx)
	if (dabr.enabled)
		set_dabr(dabr.address);
	if (iabr.enabled)
		set_iabr(iabr.address);
#endif
}

static void
remove_bpts(void)
{
	int i;
	struct bpt *bp;
	unsigned instr;

#if !defined(CONFIG_8xx)
	set_dabr(0);
	set_iabr(0);
#endif
	bp = bpts;
	for (i = 0; i < NBPTS; ++i, ++bp) {
		if (!bp->enabled)
			continue;
		if (mread(bp->address, &instr, 4) == 4
		    && instr == bpinstr
		    && mwrite(bp->address, &bp->instr, 4) != 4)
			printf("Couldn't remove breakpoint at %x\n",
			       bp->address);
		store_inst((void *) bp->address);
	}
}

static char *last_cmd;

/* Command interpreting routine */
static int
cmds(struct pt_regs *excp)
{
	int cmd;

	last_cmd = NULL;
	for(;;) {
#ifdef CONFIG_SMP
		printf("%d:", smp_processor_id());
#endif /* CONFIG_SMP */
		printf("mon> ");
		fflush(stdout);
		flush_input();
		termch = 0;
		cmd = skipbl();
		if( cmd == '\n' ) {
			if (last_cmd == NULL)
				continue;
			take_input(last_cmd);
			last_cmd = NULL;
			cmd = inchar();
		}
		switch (cmd) {
		case 'm':
			cmd = inchar();
			switch (cmd) {
			case 'm':
			case 's':
			case 'd':
				memops(cmd);
				break;
			case 'l':
				memlocate();
				break;
			case 'z':
				memzcan();
				break;
			default:
				termch = cmd;
				memex();
			}
			break;
		case 'd':
			dump();
			break;
		case 'l':
			symbol_lookup();
			break;
		case 'r':
			if (excp != NULL)
				prregs(excp);	/* print regs */
			break;
		case 'e':
			if (excp == NULL)
				printf("No exception information\n");
			else
				excprint(excp);
			break;
		case 'S':
			super_regs();
			break;
		case 't':
			backtrace(excp);
			break;
		case 'f':
			cacheflush();
			break;
		case 'h':
			dump_hash_table();
			break;
		case 's':
		case 'x':
		case EOF:
			return cmd;
		case '?':
			printf(help_string);
			break;
		default:
			printf("Unrecognized command: ");
			if( ' ' < cmd && cmd <= '~' )
				putchar(cmd);
			else
				printf("\\x%x", cmd);
			printf(" (type ? for help)\n");
			break;
		case 'b':
			bpt_cmds();
			break;
		case 'C':
			csum();
			break;
#ifdef CONFIG_SMP
		case 'c':
			cpu_cmd();
			break;
#endif /* CONFIG_SMP */
#ifdef CONFIG_BOOTX_TEXT
		case 'v':
			vidcmds();
			break;
#endif
		case 'z':
			bootcmds();
			break;
		case 'p':
			proccall();
			break;
		case 'T':
			printtime();
			break;
		}
	}
}

extern unsigned tb_to_us;

#define mulhwu(x,y) \
({unsigned z; asm ("mulhwu %0,%1,%2" : "=r" (z) : "r" (x), "r" (y)); z;})

static void printtime(void)
{
	unsigned int delta;

	delta = stop_tb[smp_processor_id()][1]
		- start_tb[smp_processor_id()][1];
	delta = mulhwu(tb_to_us, delta);
	printf("%u.%06u seconds\n", delta / 1000000, delta % 1000000);
}

static void bootcmds(void)
{
	int cmd;

	cmd = inchar();
	if (cmd == 'r')
		ppc_md.restart(NULL);
	else if (cmd == 'h')
		ppc_md.halt();
	else if (cmd == 'p')
		ppc_md.power_off();
}

#ifdef CONFIG_SMP
static void cpu_cmd(void)
{
	unsigned cpu;
	int timeout;
	int cmd;

	cmd = inchar();
	if (cmd == 'i') {
		/* interrupt other cpu(s) */
		cpu = MSG_ALL_BUT_SELF;
		if (scanhex(&cpu))
			smp_send_xmon_break(cpu);
		return;
	}
	termch = cmd;
	if (!scanhex(&cpu)) {
		/* print cpus waiting or in xmon */
		printf("cpus stopped:");
		for (cpu = 0; cpu < NR_CPUS; ++cpu) {
			if (test_bit(cpu, &cpus_in_xmon)) {
				printf(" %d", cpu);
				if (cpu == smp_processor_id())
					printf("*", cpu);
			}
		}
		printf("\n");
		return;
	}
	/* try to switch to cpu specified */
	take_xmon = cpu;
	timeout = 10000000;
	while (take_xmon >= 0) {
		if (--timeout == 0) {
			/* yes there's a race here */
			take_xmon = -1;
			printf("cpu %u didn't take control\n", cpu);
			return;
		}
	}
	/* now have to wait to be given control back */
	while (test_and_set_bit(0, &got_xmon)) {
		if (take_xmon == smp_processor_id()) {
			take_xmon = -1;
			break;
		}
	}