ARK-OS/arkos/kernel/arch/powerpc/xmon/xmon.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Routines providing a simple monitor for use on the PowerMac.
 *
 * Copyright (C) 1996-2005 Paul Mackerras.
 * Copyright (C) 2001 PPC64 Team, IBM Corp
 * Copyrignt (C) 2006 Michael Ellerman, IBM Corp
 */

#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/sched/signal.h>
#include <linux/smp.h>
#include <linux/mm.h>
#include <linux/reboot.h>
#include <linux/delay.h>
#include <linux/kallsyms.h>
#include <linux/kmsg_dump.h>
#include <linux/cpumask.h>
#include <linux/export.h>
#include <linux/sysrq.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/bug.h>
#include <linux/nmi.h>
#include <linux/ctype.h>
#include <linux/highmem.h>
#include <linux/security.h>
#include <linux/debugfs.h>

#include <asm/ptrace.h>
#include <asm/smp.h>
#include <asm/string.h>
#include <asm/machdep.h>
#include <asm/xmon.h>
#include <asm/processor.h>
#include <asm/mmu.h>
#include <asm/mmu_context.h>
#include <asm/plpar_wrappers.h>
#include <asm/cputable.h>
#include <asm/rtas.h>
#include <asm/sstep.h>
#include <asm/irq_regs.h>
#include <asm/setjmp.h>
#include <asm/reg.h>
#include <asm/debug.h>
#include <asm/hw_breakpoint.h>
#include <asm/xive.h>
#include <asm/opal.h>
#include <asm/firmware.h>
#include <asm/text-patching.h>
#include <asm/sections.h>
#include <asm/inst.h>
#include <asm/interrupt.h>

#ifdef CONFIG_PPC64
#include <asm/hvcall.h>
#include <asm/paca.h>
#include <asm/lppaca.h>
#endif

#include "nonstdio.h"
#include "dis-asm.h"
#include "xmon_bpts.h"

#ifdef CONFIG_SMP
static cpumask_t cpus_in_xmon = CPU_MASK_NONE;
static unsigned long xmon_taken = 1;
static int xmon_owner;
static int xmon_gate;
static int xmon_batch;
static unsigned long xmon_batch_start_cpu;
static cpumask_t xmon_batch_cpus = CPU_MASK_NONE;
#else
#define xmon_owner 0
#endif /* CONFIG_SMP */

static unsigned long in_xmon __read_mostly = 0;
static int xmon_on = IS_ENABLED(CONFIG_XMON_DEFAULT);
static bool xmon_is_ro = IS_ENABLED(CONFIG_XMON_DEFAULT_RO_MODE);

static unsigned long adrs;
static int size = 1;
#define MAX_DUMP (64 * 1024)
static unsigned long ndump = 64;
#define MAX_IDUMP (MAX_DUMP >> 2)
static unsigned long nidump = 16;
static unsigned long ncsum = 4096;
static int termch;
static char tmpstr[KSYM_NAME_LEN];
static int tracing_enabled;

static long bus_error_jmp[JMP_BUF_LEN];
static int catch_memory_errors;
static int catch_spr_faults;
static long *xmon_fault_jmp[NR_CPUS];

/* Breakpoint stuff */
struct bpt {
	unsigned long	address;
	u32		*instr;
	atomic_t	ref_count;
	int		enabled;
	unsigned long	pad;
};

/* Bits in bpt.enabled */
#define BP_CIABR	1
#define BP_TRAP		2
#define BP_DABR		4

static struct bpt bpts[NBPTS];
static struct bpt dabr[HBP_NUM_MAX];
static struct bpt *iabr;
static unsigned int bpinstr = PPC_RAW_TRAP();

#define BP_NUM(bp)	((bp) - bpts + 1)

/* Prototypes */
static int cmds(struct pt_regs *);
static int mread(unsigned long, void *, int);
static int mwrite(unsigned long, void *, int);
static int mread_instr(unsigned long, ppc_inst_t *);
static int 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 show_pte(unsigned long);
static void prdump(unsigned long, long);
static int ppc_inst_dump(unsigned long, long, int);
static void dump_log_buf(void);

#ifdef CONFIG_SMP
static int xmon_switch_cpu(unsigned long);
static int xmon_batch_next_cpu(void);
static int batch_cmds(struct pt_regs *);
#endif

#ifdef CONFIG_PPC_POWERNV
static void dump_opal_msglog(void);
#else
static inline void dump_opal_msglog(void)
{
	printf("Machine is not running OPAL firmware.\n");
}
#endif

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 long *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 int  read_spr(int, unsigned long *);
static void write_spr(int, unsigned long);
static void super_regs(void);
static void remove_bpts(void);
static void insert_bpts(void);
static void remove_cpu_bpts(void);
static void insert_cpu_bpts(void);
static struct bpt *at_breakpoint(unsigned long pc);
static struct bpt *in_breakpoint_table(unsigned long pc, unsigned long *offp);
static int  do_step(struct pt_regs *);
static void bpt_cmds(void);
static void cacheflush(void);
static int  cpu_cmd(void);
static void csum(void);
static void bootcmds(void);
static void proccall(void);
static void show_tasks(void);
void dump_segments(void);
static void symbol_lookup(void);
static void xmon_show_stack(unsigned long sp, unsigned long lr,
			    unsigned long pc);
static void xmon_print_symbol(unsigned long address, const char *mid,
			      const char *after);
static const char *getvecname(unsigned long vec);

#ifdef CONFIG_44x
static void dump_tlb_44x(void);
#endif
#ifdef CONFIG_PPC_BOOK3E_64
static void dump_tlb_book3e(void);
#endif

static void clear_all_bpt(void);

#ifdef CONFIG_PPC64
#define REG		"%.16lx"
#else
#define REG		"%.8lx"
#endif

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

static const char *xmon_ro_msg = "Operation disabled: xmon in read-only mode\n";

static char *help_string = "\
Commands:\n\
  b	show breakpoints\n\
  bd	set data breakpoint\n\
  bi	set instruction breakpoint\n\
  bc	clear breakpoint\n"
#ifdef CONFIG_SMP
  "\
  c	print cpus stopped in xmon\n\
  c#	try to switch to cpu number h (in hex)\n\
  c# $	run command '$' (one of 'r','S' or 't') on all cpus in xmon\n"
#endif
  "\
  C	checksum\n\
  d	dump bytes\n\
  d1	dump 1 byte values\n\
  d2	dump 2 byte values\n\
  d4	dump 4 byte values\n\
  d8	dump 8 byte values\n\
  di	dump instructions\n\
  df	dump float values\n\
  dd	dump double values\n\
  dl    dump the kernel log buffer\n"
#ifdef CONFIG_PPC_POWERNV
  "\
  do    dump the OPAL message log\n"
#endif
#ifdef CONFIG_PPC64
  "\
  dp[#]	dump paca for current cpu, or cpu #\n\
  dpa	dump paca for all possible cpus\n"
#endif
  "\
  dr	dump stream of raw bytes\n\
  dv	dump virtual address translation \n\
  dt	dump the tracing buffers (uses printk)\n\
  dtc	dump the tracing buffers for current CPU (uses printk)\n\
"
#ifdef CONFIG_PPC_POWERNV
"  dx#   dump xive on CPU #\n\
  dxi#  dump xive irq state #\n\
  dxa   dump xive on all CPUs\n"
#endif
"  e	print exception information\n\
  f	flush cache\n\
  la	lookup symbol+offset of specified address\n\
  ls	lookup address of specified symbol\n\
  lp s [#]	lookup address of percpu symbol s for current cpu, or cpu #\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\
  ml	locate a block of memory\n\
  mz	zero a block of memory\n\
  mi	show information about memory allocation\n\
  p 	call a procedure\n\
  P 	list processes/tasks\n\
  r	print registers\n\
  s	single step\n"
"  S	print special registers\n\
  Sa    print all SPRs\n\
  Sr #	read SPR #\n\
  Sw #v write v to SPR #\n\
  t	print backtrace\n\
  x	exit monitor and recover\n\
  X	exit monitor and don't recover\n"
#if defined(CONFIG_PPC_BOOK3S_64)
"  u	dump segment table or SLB\n"
#elif defined(CONFIG_PPC_BOOK3S_32)
"  u	dump segment registers\n"
#elif defined(CONFIG_44x) || defined(CONFIG_PPC_BOOK3E_64)
"  u	dump TLB\n"
#endif
"  U	show uptime information\n"
"  ?	help\n"
"  # n	limit output to n lines per page (for dp, dpa, dl)\n"
"  zr	reboot\n"
"  zh	halt\n"
;

#ifdef CONFIG_SECURITY
static bool xmon_is_locked_down(void)
{
	static bool lockdown;

	if (!lockdown) {
		lockdown = !!security_locked_down(LOCKDOWN_XMON_RW);
		if (lockdown) {
			printf("xmon: Disabled due to kernel lockdown\n");
			xmon_is_ro = true;
		}
	}

	if (!xmon_is_ro) {
		xmon_is_ro = !!security_locked_down(LOCKDOWN_XMON_WR);
		if (xmon_is_ro)
			printf("xmon: Read-only due to kernel lockdown\n");
	}

	return lockdown;
}
#else /* CONFIG_SECURITY */
static inline bool xmon_is_locked_down(void)
{
	return false;
}
#endif

static struct pt_regs *xmon_regs;

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

static inline void cflush(void *p)
{
	asm volatile ("dcbf 0,%0; icbi 0,%0" : : "r" (p));
}

static inline void cinval(void *p)
{
	asm volatile ("dcbi 0,%0; icbi 0,%0" : : "r" (p));
}

/**
 * write_ciabr() - write the CIABR SPR
 * @ciabr:	The value to write.
 *
 * This function writes a value to the CIARB register either directly
 * through mtspr instruction if the kernel is in HV privilege mode or
 * call a hypervisor function to achieve the same in case the kernel
 * is in supervisor privilege mode.
 */
static void write_ciabr(unsigned long ciabr)
{
	if (!cpu_has_feature(CPU_FTR_ARCH_207S))
		return;

	if (cpu_has_feature(CPU_FTR_HVMODE)) {
		mtspr(SPRN_CIABR, ciabr);
		return;
	}
	plpar_set_ciabr(ciabr);
}

/**
 * set_ciabr() - set the CIABR
 * @addr:	The value to set.
 *
 * This function sets the correct privilege value into the HW
 * breakpoint address before writing it up in the CIABR register.
 */
static void set_ciabr(unsigned long addr)
{
	addr &= ~CIABR_PRIV;

	if (cpu_has_feature(CPU_FTR_HVMODE))
		addr |= CIABR_PRIV_HYPER;
	else
		addr |= CIABR_PRIV_SUPER;
	write_ciabr(addr);
}

/*
 * Disable surveillance (the service processor watchdog function)
 * while we are in xmon.
 * XXX we should re-enable it when we leave. :)
 */
#define SURVEILLANCE_TOKEN	9000

static inline void disable_surveillance(void)
{
#ifdef CONFIG_PPC_PSERIES
	/* Since this can't be a module, args should end up below 4GB. */
	static struct rtas_args args;
	const s32 token = rtas_function_token(RTAS_FN_SET_INDICATOR);

	/*
	 * At this point we have got all the cpus we can into
	 * xmon, so there is hopefully no other cpu calling RTAS
	 * at the moment, even though we don't take rtas.lock.
	 * If we did try to take rtas.lock there would be a
	 * real possibility of deadlock.
	 */
	if (token == RTAS_UNKNOWN_SERVICE)
		return;

	rtas_call_unlocked(&args, token, 3, 1, NULL,
			   SURVEILLANCE_TOKEN, 0, 0);

#endif /* CONFIG_PPC_PSERIES */
}

#ifdef CONFIG_SMP
static int xmon_speaker;

static void get_output_lock(void)
{
	int me = smp_processor_id() + 0x100;
	int last_speaker = 0, prev;
	long timeout;

	if (xmon_speaker == me)
		return;

	for (;;) {
		last_speaker = cmpxchg(&xmon_speaker, 0, me);
		if (last_speaker == 0)
			return;

		/*
		 * Wait a full second for the lock, we might be on a slow
		 * console, but check every 100us.
		 */
		timeout = 10000;
		while (xmon_speaker == last_speaker) {
			if (--timeout > 0) {
				udelay(100);
				continue;
			}

			/* hostile takeover */
			prev = cmpxchg(&xmon_speaker, last_speaker, me);
			if (prev == last_speaker)
				return;
			break;
		}
	}
}

static void release_output_lock(void)
{
	xmon_speaker = 0;
}

int cpus_are_in_xmon(void)
{
	return !cpumask_empty(&cpus_in_xmon);
}

static bool wait_for_other_cpus(int ncpus)
{
	unsigned long timeout;

	/* We wait for 2s, which is a metric "little while" */
	for (timeout = 20000; timeout != 0; --timeout) {
		if (cpumask_weight(&cpus_in_xmon) >= ncpus)
			return true;
		udelay(100);
		barrier();
	}

	return false;
}
#else /* CONFIG_SMP */
static inline void get_output_lock(void) {}
static inline void release_output_lock(void) {}
#endif

static void xmon_touch_watchdogs(void)
{
	touch_softlockup_watchdog_sync();
	rcu_cpu_stall_reset();
	touch_nmi_watchdog();
}

static int xmon_core(struct pt_regs *regs, volatile int fromipi)
{
	volatile int cmd = 0;
	struct bpt *volatile bp;
	long recurse_jmp[JMP_BUF_LEN];
	bool locked_down;
	unsigned long offset;
	unsigned long flags;
#ifdef CONFIG_SMP
	int cpu;
	int secondary;
#endif

	local_irq_save(flags);
	hard_irq_disable();

	locked_down = xmon_is_locked_down();

	if (!fromipi) {
		tracing_enabled = tracing_is_on();
		tracing_off();
	}

	bp = in_breakpoint_table(regs->nip, &offset);
	if (bp != NULL) {
		regs_set_return_ip(regs, bp->address + offset);
		atomic_dec(&bp->ref_count);
	}

	remove_cpu_bpts();

#ifdef CONFIG_SMP
	cpu = smp_processor_id();
	if (cpumask_test_cpu(cpu, &cpus_in_xmon)) {
		/*
		 * We catch SPR read/write faults here because the 0x700, 0xf60
		 * etc. handlers don't call debugger_fault_handler().
		 */
		if (catch_spr_faults)
			longjmp(bus_error_jmp, 1);
		get_output_lock();
		excprint(regs);
		printf("cpu 0x%x: Exception %lx %s in xmon, "
		       "returning to main loop\n",
		       cpu, regs->trap, getvecname(TRAP(regs)));
		release_output_lock();
		longjmp(xmon_fault_jmp[cpu], 1);
	}

	if (setjmp(recurse_jmp) != 0) {
		if (!in_xmon || !xmon_gate) {
			get_output_lock();
			printf("xmon: WARNING: bad recursive fault "
			       "on cpu 0x%x\n", cpu);
			release_output_lock();
			goto waiting;
		}
		secondary = !(xmon_taken && cpu == xmon_owner);
		goto cmdloop;
	}

	xmon_fault_jmp[cpu] = recurse_jmp;

	bp = NULL;
	if ((regs->msr & (MSR_IR|MSR_PR|MSR_64BIT)) == (MSR_IR|MSR_64BIT))
		bp = at_breakpoint(regs->nip);
	if (bp || regs_is_unrecoverable(regs))
		fromipi = 0;

	if (!fromipi) {
		get_output_lock();
		if (!locked_down)
			excprint(regs);
		if (bp) {
			printf("cpu 0x%x stopped at breakpoint 0x%tx (",
			       cpu, BP_NUM(bp));
			xmon_print_symbol(regs->nip, " ", ")\n");
		}
		if (regs_is_unrecoverable(regs))
			printf("WARNING: exception is not recoverable, "
			       "can't continue\n");
		release_output_lock();
	}

	cpumask_set_cpu(cpu, &cpus_in_xmon);

 waiting:
	secondary = 1;
	spin_begin();
	while (secondary && !xmon_gate) {
		if (in_xmon == 0) {
			if (fromipi) {
				spin_end();
				goto leave;
			}
			secondary = test_and_set_bit(0, &in_xmon);
		}
		spin_cpu_relax();
		touch_nmi_watchdog();
	}
	spin_end();

	if (!secondary && !xmon_gate) {
		/* we are the first cpu to come in */
		/* interrupt other cpu(s) */
		int ncpus = num_online_cpus();

		xmon_owner = cpu;
		mb();
		if (ncpus > 1) {
			/*
			 * A system reset (trap == 0x100) can be triggered on
			 * all CPUs, so when we come in via 0x100 try waiting
			 * for the other CPUs to come in before we send the
			 * debugger break (IPI). This is similar to
			 * crash_kexec_secondary().
			 */
			if (TRAP(regs) !=  INTERRUPT_SYSTEM_RESET || !wait_for_other_cpus(ncpus))
				smp_send_debugger_break();

			wait_for_other_cpus(ncpus);
		}
		remove_bpts();
		disable_surveillance();

		if (!locked_down) {
			/* for breakpoint or single step, print curr insn */
			if (bp || TRAP(regs) == INTERRUPT_TRACE)
				ppc_inst_dump(regs->nip, 1, 0);
			printf("enter ? for help\n");
		}

		mb();
		xmon_gate = 1;
		barrier();
		touch_nmi_watchdog();
	}

 cmdloop:
	while (in_xmon) {
		if (secondary) {
			spin_begin();
			if (cpu == xmon_owner) {
				if (!test_and_set_bit(0, &xmon_taken)) {
					secondary = 0;
					spin_end();
					continue;
				}
				/* missed it */
				while (cpu == xmon_owner)
					spin_cpu_relax();
			}
			spin_cpu_relax();
			touch_nmi_watchdog();
		} else {
			cmd = 1;
			if (xmon_batch)
				cmd = batch_cmds(regs);
			if (!locked_down && cmd)
				cmd = cmds(regs);
			if (locked_down || cmd != 0) {
				/* exiting xmon */
				insert_bpts();
				xmon_gate = 0;
				wmb();
				in_xmon = 0;
				break;
			}
			/* have switched to some other cpu */
			secondary = 1;
		}
	}
 leave:
	cpumask_clear_cpu(cpu, &cpus_in_xmon);
	xmon_fault_jmp[cpu] = NULL;
#else
	/* UP is simple... */
	if (in_xmon) {
		printf("Exception %lx %s in xmon, returning to main loop\n",
		       regs->trap, getvecname(TRAP(regs)));
		longjmp(xmon_fault_jmp[0], 1);
	}
	if (setjmp(recurse_jmp) == 0) {
		xmon_fault_jmp[0] = recurse_jmp;
		in_xmon = 1;

		excprint(regs);
		bp = at_breakpoint(regs->nip);
		if (bp) {
			printf("Stopped at breakpoint %tx (", BP_NUM(bp));
			xmon_print_symbol(regs->nip, " ", ")\n");
		}
		if (regs_is_unrecoverable(regs))
			printf("WARNING: exception is not recoverable, "
			       "can't continue\n");
		remove_bpts();
		disable_surveillance();
		if (!locked_down) {
			/* for breakpoint or single step, print current insn */
			if (bp || TRAP(regs) == INTERRUPT_TRACE)
				ppc_inst_dump(regs->nip, 1, 0);
			printf("enter ? for help\n");
		}
	}

	if (!locked_down)
		cmd = cmds(regs);

	insert_bpts();
	in_xmon = 0;
#endif

#ifdef CONFIG_BOOKE
	if (regs->msr & MSR_DE) {
		bp = at_breakpoint(regs->nip);
		if (bp != NULL) {
			regs_set_return_ip(regs, (unsigned long) &bp->instr[0]);
			atomic_inc(&bp->ref_count);
		}
	}
#else
	if ((regs->msr & (MSR_IR|MSR_PR|MSR_64BIT)) == (MSR_IR|MSR_64BIT)) {
		bp = at_breakpoint(regs->nip);
		if (bp != NULL) {
			int stepped = emulate_step(regs, ppc_inst_read(bp->instr));
			if (stepped == 0) {
				regs_set_return_ip(regs, (unsigned long) &bp->instr[0]);
				atomic_inc(&bp->ref_count);
			} else if (stepped < 0) {
				printf("Couldn't single-step %s instruction\n",
				    IS_RFID(ppc_inst_read(bp->instr))? "rfid": "mtmsrd");
			}
		}
	}
#endif
	if (locked_down)
		clear_all_bpt();
	else
		insert_cpu_bpts();

	xmon_touch_watchdogs();
	local_irq_restore(flags);

	return cmd != 'X' && cmd != EOF;
}

int xmon(struct pt_regs *excp)
{
	struct pt_regs regs;

	if (excp == NULL) {
		ppc_save_regs(&regs);
		excp = &regs;
	}

	return xmon_core(excp, 0);
}
EXPORT_SYMBOL(xmon);

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

static int xmon_bpt(struct pt_regs *regs)
{
	struct bpt *bp;
	unsigned long offset;

	if ((regs->msr & (MSR_IR|MSR_PR|MSR_64BIT)) != (MSR_IR|MSR_64BIT))
		return 0;

	/* Are we at the trap at bp->instr[1] for some bp? */
	bp = in_breakpoint_table(regs->nip, &offset);
	if (bp != NULL && (offset == 4 || offset == 8)) {
		regs_set_return_ip(regs, bp->address + offset);
		atomic_dec(&bp->ref_count);
		return 1;
	}

	/* Are we at a breakpoint? */
	bp = at_breakpoint(regs->nip);
	if (!bp)
		return 0;

	xmon_core(regs, 0);

	return 1;
}

static int xmon_sstep(struct pt_regs *regs)
{
	if (user_mode(regs))
		return 0;
	xmon_core(regs, 0);
	return 1;
}

static int xmon_break_match(struct pt_regs *regs)
{
	int i;

	if ((regs->msr & (MSR_IR|MSR_PR|MSR_64BIT)) != (MSR_IR|MSR_64BIT))
		return 0;
	for (i = 0; i < nr_wp_slots(); i++) {
		if (dabr[i].enabled)
			goto found;
	}
	return 0;

found:
	xmon_core(regs, 0);
	return 1;
}

static int xmon_iabr_match(struct pt_regs *regs)
{
	if ((regs->msr & (MSR_IR|MSR_PR|MSR_64BIT)) != (MSR_IR|MSR_64BIT))
		return 0;
	if (iabr == NULL)
		return 0;
	xmon_core(regs, 0);
	return 1;
}

static int xmon_ipi(struct pt_regs *regs)
{
#ifdef CONFIG_SMP
	if (in_xmon && !cpumask_test_cpu(smp_processor_id(), &cpus_in_xmon))
		xmon_core(regs, 1);
#endif
	return 0;
}

static int xmon_fault_handler(struct pt_regs *regs)
{
	struct bpt *bp;
	unsigned long offset;

	if (in_xmon && catch_memory_errors)
		handle_fault(regs);	/* doesn't return */

	if ((regs->msr & (MSR_IR|MSR_PR|MSR_64BIT)) == (MSR_IR|MSR_64BIT)) {
		bp = in_breakpoint_table(regs->nip, &offset);
		if (bp != NULL) {
			regs_set_return_ip(regs, bp->address + offset);
			atomic_dec(&bp->ref_count);
		}
	}

	return 0;
}

/* Force enable xmon if not already enabled */
static inline void force_enable_xmon(void)
{
	/* Enable xmon hooks if needed */
	if (!xmon_on) {
		printf("xmon: Enabling debugger hooks\n");
		xmon_on = 1;
	}
}

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

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

static struct bpt *in_breakpoint_table(unsigned long nip, unsigned long *offp)
{
	unsigned long off;

	off = nip - (unsigned long)bpt_table;
	if (off >= sizeof(bpt_table))
		return NULL;
	*offp = off & (BPT_SIZE - 1);
	if (off & 3)
		return NULL;
	return bpts + (off / BPT_SIZE);
}

static struct bpt *new_breakpoint(unsigned long a)
{
	struct bpt *bp;

	a &= ~3UL;
	bp = at_breakpoint(a);
	if (bp)
		return bp;

	for (bp = bpts; bp < &bpts[NBPTS]; ++bp) {
		if (!bp->enabled && atomic_read(&bp->ref_count) == 0) {
			bp->address = a;
			bp->instr = (void *)(bpt_table + ((bp - bpts) * BPT_WORDS));
			return bp;
		}
	}

	printf("Sorry, no free breakpoints.  Please clear one first.\n");
	return NULL;
}

static void insert_bpts(void)
{
	int i;
	ppc_inst_t instr, instr2;
	struct bpt *bp, *bp2;

	bp = bpts;
	for (i = 0; i < NBPTS; ++i, ++bp) {
		if ((bp->enabled & (BP_TRAP|BP_CIABR)) == 0)
			continue;
		if (!mread_instr(bp->address, &instr)) {
			printf("Couldn't read instruction at %lx, "
			       "disabling breakpoint there\n", bp->address);
			bp->enabled = 0;
			continue;
		}
		if (!can_single_step(ppc_inst_val(instr))) {
			printf("Breakpoint at %lx is on an instruction that can't be single stepped, disabling it\n",
					bp->address);
			bp->enabled = 0;
			continue;
		}
		/*
		 * Check the address is not a suffix by looking for a prefix in
		 * front of it.
		 */
		if (mread_instr(bp->address - 4, &instr2) == 8) {
			printf("Breakpoint at %lx is on the second word of a prefixed instruction, disabling it\n",
			       bp->address);
			bp->enabled = 0;
			continue;
		}
		/*
		 * We might still be a suffix - if the prefix has already been
		 * replaced by a breakpoint we won't catch it with the above
		 * test.
		 */
		bp2 = at_breakpoint(bp->address - 4);
		if (bp2 && ppc_inst_prefixed(ppc_inst_read(bp2->instr))) {
			printf("Breakpoint at %lx is on the second word of a prefixed instruction, disabling it\n",
			       bp->address);
			bp->enabled = 0;
			continue;
		}

		patch_instruction(bp->instr, instr);
		patch_instruction(ppc_inst_next(bp->instr, bp->instr),
				  ppc_inst(bpinstr));
		if (bp->enabled & BP_CIABR)
			continue;
		if (patch_instruction((u32 *)bp->address,
				      ppc_inst(bpinstr)) != 0) {
			printf("Couldn't write instruction at %lx, "
			       "disabling breakpoint there\n", bp->address);
			bp->enabled &= ~BP_TRAP;
			continue;
		}
	}
}

static void insert_cpu_bpts(void)
{
	int i;
	struct arch_hw_breakpoint brk;

	for (i = 0; i < nr_wp_slots(); i++) {
		if (dabr[i].enabled) {
			brk.address = dabr[i].address;
			brk.type = (dabr[i].enabled & HW_BRK_TYPE_DABR) | HW_BRK_TYPE_PRIV_ALL;
			brk.len = 8;
			brk.hw_len = 8;
			__set_breakpoint(i, &brk);
		}
	}

	if (iabr)
		set_ciabr(iabr->address);
}

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

	bp = bpts;
	for (i = 0; i < NBPTS; ++i, ++bp) {
		if ((bp->enabled & (BP_TRAP|BP_CIABR)) != BP_TRAP)
			continue;
		if (mread_instr(bp->address, &instr)
		    && ppc_inst_equal(instr, ppc_inst(bpinstr))
		    && patch_instruction(
			(u32 *)bp->address, ppc_inst_read(bp->instr)) != 0)
			printf("Couldn't remove breakpoint at %lx\n",
			       bp->address);
	}
}

static void remove_cpu_bpts(void)
{
	hw_breakpoint_disable();
	write_ciabr(0);
}

/* Based on uptime_proc_show(). */
static void
show_uptime(void)
{
	struct timespec64 uptime;

	if (setjmp(bus_error_jmp) == 0) {
		catch_memory_errors = 1;
		sync();

		ktime_get_coarse_boottime_ts64(&uptime);
		printf("Uptime: %lu.%.2lu seconds\n", (unsigned long)uptime.tv_sec,
			((unsigned long)uptime.tv_nsec / (NSEC_PER_SEC/100)));

		sync();
		__delay(200);						\
	}
	catch_memory_errors = 0;
}

static void set_lpp_cmd(void)
{
	unsigned long lpp;

	if (!scanhex(&lpp)) {
		printf("Invalid number.\n");
		lpp = 0;
	}
	xmon_set_pagination_lpp(lpp);
}
/* Command interpreting routine */
static char *last_cmd;

static int
cmds(struct pt_regs *excp)
{
	int cmd = 0;

	last_cmd = NULL;
	xmon_regs = excp;

	xmon_show_stack(excp->gpr[1], excp->link, excp->nip);

	for(;;) {
#ifdef CONFIG_SMP
		printf("%x:", smp_processor_id());
#endif /* CONFIG_SMP */
		printf("mon> ");
		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':
				if (xmon_is_ro) {
					printf(xmon_ro_msg);
					break;
				}
				memzcan();
				break;
			case 'i':
				show_mem();
				break;
			default:
				termch = cmd;
				memex();
			}
			break;
		case 'd':
			dump();
			break;
		case 'l':
			symbol_lookup();
			break;
		case 'r':
			prregs(excp);	/* print regs */
			break;
		case 'e':
			excprint(excp);
			break;
		case 'S':
			super_regs();
			break;
		case 't':
			backtrace(excp);
			break;
		case 'f':
			cacheflush();
			break;
		case 's':
			if (do_step(excp))
				return cmd;
			break;
		case 'x':
		case 'X':
			if (tracing_enabled)
				tracing_on();
			return cmd;
		case EOF:
			printf(" <no input ...>\n");
			mdelay(2000);
			return cmd;
		case '?':
			xmon_puts(help_string);
			break;
		case '#':
			set_lpp_cmd();
			break;
		case 'b':
			bpt_cmds();
			break;
		case 'C':
			csum();
			break;
		case 'c':
			if (cpu_cmd())
				return 0;
			break;
		case 'z':
			bootcmds();
			break;
		case 'p':
			if (xmon_is_ro) {
				printf(xmon_ro_msg);
				break;
			}
			proccall();
			break;
		case 'P':
			show_tasks();
			break;
#if defined(CONFIG_PPC_BOOK3S_32) || defined(CONFIG_PPC_64S_HASH_MMU)
		case 'u':
			dump_segments();
			break;
#elif defined(CONFIG_44x)
		case 'u':
			dump_tlb_44x();
			break;
#elif defined(CONFIG_PPC_BOOK3E_64)
		case 'u':
			dump_tlb_book3e();
			break;
#endif
		case 'U':
			show_uptime();
			break;
		default:
			printf("Unrecognized command: ");
			do {
				if (' ' < cmd && cmd <= '~')
					putchar(cmd);
				else
					printf("\\x%x", cmd);
				cmd = inchar();
			} while (cmd != '\n');
			printf(" (type ? for help)\n");
			break;
		}
	}
}

#ifdef CONFIG_BOOKE
static int do_step(struct pt_regs *regs)
{
	regs_set_return_msr(regs, regs->msr | MSR_DE);
	mtspr(SPRN_DBCR0, mfspr(SPRN_DBCR0) | DBCR0_IC | DBCR0_IDM);
	return 1;
}
#else
/*
 * Step a single instruction.
 * Some instructions we emulate, others we execute with MSR_SE set.
 */
static int do_step(struct pt_regs *regs)
{
	ppc_inst_t instr;
	int stepped;

	force_enable_xmon();
	/* check we are in 64-bit kernel mode, translation enabled */
	if ((regs->msr & (MSR_64BIT|MSR_PR|MSR_IR)) == (MSR_64BIT|MSR_IR)) {
		if (mread_instr(regs->nip, &instr)) {
			stepped = emulate_step(regs, instr);
			if (stepped < 0) {
				printf("Couldn't single-step %s instruction\n",
				       (IS_RFID(instr)? "rfid": "mtmsrd"));
				return 0;
			}
			if (stepped > 0) {
				set_trap(regs, 0xd00);
				printf("stepped to ");
				xmon_print_symbol(regs->nip, " ", "\n");
				ppc_inst_dump(regs->nip, 1, 0);
				return 0;
			}
		}
	}
	regs_set_return_msr(regs, regs->msr | MSR_SE);
	return 1;
}
#endif

static void bootcmds(void)
{
	char tmp[64];
	int cmd;

	cmd = inchar();
	if (cmd == 'r') {
		getstring(tmp, 64);
		ppc_md.restart(tmp);
	} else if (cmd == 'h') {
		ppc_md.halt();
	} else if (cmd == 'p') {
		do_kernel_power_off();
	}
}

#ifdef CONFIG_SMP
static int xmon_switch_cpu(unsigned long cpu)
{
	int timeout;

	xmon_taken = 0;
	mb();
	xmon_owner = cpu;
	timeout = 10000000;
	while (!xmon_taken) {
		if (--timeout == 0) {
			if (test_and_set_bit(0, &xmon_taken))
				break;
			/* take control back */
			mb();
			xmon_owner = smp_processor_id();
			printf("cpu 0x%lx didn't take control\n", cpu);
			return 0;
		}
		barrier();
	}
	return 1;
}

static int xmon_batch_next_cpu(void)
{
	unsigned long cpu;

	for_each_cpu_wrap(cpu, &xmon_batch_cpus, xmon_batch_start_cpu) {
		if (xmon_batch_start_cpu == -1)
			xmon_batch_start_cpu = cpu;
		if (xmon_switch_cpu(cpu))
			return 0;
		cpumask_clear_cpu(cpu, &xmon_batch_cpus);
	}

	xmon_batch = 0;
	printf("%x:mon> \n", smp_processor_id());
	return 1;
}

static int batch_cmds(struct pt_regs *excp)
{
	int cmd;

	/* simulate command entry */
	cmd = xmon_batch;
	termch = '\n';

	last_cmd = NULL;
	xmon_regs = excp;

	printf("%x:", smp_processor_id());
	printf("mon> ");
	printf("%c\n", (char)cmd);

	switch (cmd) {
	case 'r':
		prregs(excp);	/* print regs */
		break;
	case 'S':
		super_regs();
		break;
	case 't':
		backtrace(excp);
		break;
	}

	cpumask_clear_cpu(smp_processor_id(), &xmon_batch_cpus);

	return xmon_batch_next_cpu();
}

static int cpu_cmd(void)
{
	unsigned long cpu, first_cpu, last_cpu;

	cpu = skipbl();
	if (cpu == '#') {
		xmon_batch = skipbl();
		if (xmon_batch) {
			switch (xmon_batch) {
			case 'r':
			case 'S':
			case 't':
				cpumask_copy(&xmon_batch_cpus, &cpus_in_xmon);
				if (cpumask_weight(&xmon_batch_cpus) <= 1) {
					printf("There are no other cpus in xmon\n");
					break;
				}
				xmon_batch_start_cpu = -1;
				if (!xmon_batch_next_cpu())
					return 1;
				break;
			default:
				printf("c# only supports 'r', 'S' and 't' commands\n");
			}
			xmon_batch = 0;
			return 0;
		}
	}
	termch = cpu;

	if (!scanhex(&cpu) || cpu >= num_possible_cpus()) {
		/* print cpus waiting or in xmon */
		printf("cpus stopped:");
		last_cpu = first_cpu = NR_CPUS;
		for_each_possible_cpu(cpu) {
			if (cpumask_test_cpu(cpu, &cpus_in_xmon)) {
				if (cpu == last_cpu + 1) {
					last_cpu = cpu;
				} else {
					if (last_cpu != first_cpu)
						printf("-0x%lx", last_cpu);
					last_cpu = first_cpu = cpu;
					printf(" 0x%lx", cpu);
				}
			}
		}
		if (last_cpu != first_cpu)
			printf("-0x%lx", last_cpu);
		printf("\n");
		return 0;
	}
	/* try to switch to cpu specified */
	if (!cpumask_test_cpu(cpu, &cpus_in_xmon)) {
		printf("cpu 0x%lx isn't in xmon\n", cpu);
#ifdef CONFIG_PPC64
		printf("backtrace of paca[0x%lx].saved_r1 (possibly stale):\n", cpu);
		xmon_show_stack(paca_ptrs[cpu]->saved_r1, 0, 0);
#endif
		return 0;
	}

	return xmon_switch_cpu(cpu);
}
#else
static int cpu_cmd(void)
{
	return 0;
}
#endif /* CONFIG_SMP */

static unsigned short fcstab[256] = {
	0x0000, 0x1189, 0x2312, 0x329b, 0x4624, 0x57ad, 0x6536, 0x74bf,
	0x8c48, 0x9dc1, 0xaf5a, 0xbed3, 0xca6c, 0xdbe5, 0xe97e, 0xf8f7,
	0x1081, 0x0108, 0x3393, 0x221a, 0x56a5, 0x472c, 0x75b7, 0x643e,
	0x9cc9, 0x8d40, 0xbfdb, 0xae52, 0xdaed, 0xcb64, 0xf9ff, 0xe876,
	0x2102, 0x308b, 0x0210, 0x1399, 0x6726, 0x76af, 0x4434, 0x55bd,
	0xad4a, 0xbcc3, 0x8e58, 0x9fd1, 0xeb6e, 0xfae7, 0xc87c, 0xd9f5,
	0x3183, 0x200a, 0x1291, 0x0318, 0x77a7, 0x662e, 0x54b5, 0x453c,
	0xbdcb, 0xac42, 0x9ed9, 0x8f50, 0xfbef, 0xea66, 0xd8fd, 0xc974,
	0x4204, 0x538d, 0x6116, 0x709f, 0x0420, 0x15a9, 0x2732, 0x36bb,
	0xce4c, 0xdfc5, 0xed5e, 0xfcd7, 0x8868, 0x99e1, 0xab7a, 0xbaf3,
	0x5285, 0x430c, 0x7197, 0x601e, 0x14a1, 0x0528, 0x37b3, 0x263a,
	0xdecd, 0xcf44, 0xfddf, 0xec56, 0x98e9, 0x8960, 0xbbfb, 0xaa72,
	0x6306, 0x728f, 0x4014, 0x519d, 0x2522, 0x34ab, 0x0630, 0x17b9,
	0xef4e, 0xfec7, 0xcc5c, 0xddd5, 0xa96a, 0xb8e3, 0x8a78, 0x9bf1,
	0x7387, 0x620e, 0x5095, 0x411c, 0x35a3, 0x242a, 0x16b1, 0x0738,
	0xffcf, 0xee46, 0xdcdd, 0xcd54, 0xb9eb, 0xa862, 0x9af9, 0x8b70,
	0x8408, 0x9581, 0xa71a, 0xb693, 0xc22c, 0xd3a5, 0xe13e, 0xf0b7,
	0x0840, 0x19c9, 0x2b52, 0x3adb, 0x4e64, 0x5fed, 0x6d76, 0x7cff,
	0x9489, 0x8500, 0xb79b, 0xa612, 0xd2ad, 0xc324, 0xf1bf, 0xe036,
	0x18c1, 0x0948, 0x3bd3, 0x2a5a, 0x5ee5, 0x4f6c, 0x7df7, 0x6c7e,
	0xa50a, 0xb483, 0x8618, 0x9791, 0xe32e, 0xf2a7, 0xc03c, 0xd1b5,
	0x2942, 0x38cb, 0x0a50, 0x1bd9, 0x6f66, 0x7eef, 0x4c74, 0x5dfd,
	0xb58b, 0xa402, 0x9699, 0x8710, 0xf3af, 0xe226, 0xd0bd, 0xc134,
	0x39c3, 0x284a, 0x1ad1, 0x0b58, 0x7fe7, 0x6e6e, 0x5cf5, 0x4d7c,
	0xc60c, 0xd785, 0xe51e, 0xf497, 0x8028, 0x91a1, 0xa33a, 0xb2b3,
	0x4a44, 0x5bcd, 0x6956, 0x78df, 0x0c60, 0x1de9, 0x2f72, 0x3efb,
	0xd68d, 0xc704, 0xf59f, 0xe416, 0x90a9, 0x8120, 0xb3bb, 0xa232,
	0x5ac5, 0x4b4c, 0x79d7, 0x685e, 0x1ce1, 0x0d68, 0x3ff3, 0x2e7a,
	0xe70e, 0xf687, 0xc41c, 0xd595, 0xa12a, 0xb0a3, 0x8238, 0x93b1,
	0x6b46, 0x7acf, 0x4854, 0x59dd, 0x2d62, 0x3ceb, 0x0e70, 0x1ff9,
	0xf78f, 0xe606, 0xd49d, 0xc514, 0xb1ab, 0xa022, 0x92b9, 0x8330,
	0x7bc7, 0x6a4e, 0x58d5, 0x495c, 0x3de3, 0x2c6a, 0x1ef1, 0x0f78
};

#define FCS(fcs, c)	(((fcs) >> 8) ^ fcstab[((fcs) ^ (c)) & 0xff])

static void
csum(void)
{
	unsigned int i;
	unsigned short fcs;
	unsigned char v;

	if (!scanhex(&adrs))
		return;
	if (!scanhex(&ncsum))
		return;
	fcs = 0xffff;
	for (i = 0; i < ncsum; ++i) {
		if (mread(adrs+i, &v, 1) == 0) {
			printf("csum stopped at "REG"\n", adrs+i);
			break;
		}
		fcs = FCS(fcs, v);
	}
	printf("%x\n", fcs);
}

/*
 * Check if this is a suitable place to put a breakpoint.
 */
static long check_bp_loc(unsigned long addr)
{
	ppc_inst_t instr;

	addr &= ~3;
	if (!is_kernel_addr(addr)) {
		printf("Breakpoints may only be placed at kernel addresses\n");
		return 0;
	}
	if (!mread_instr(addr, &instr)) {
		printf("Can't read instruction at address %lx\n", addr);
		return 0;
	}
	if (!can_single_step(ppc_inst_val(instr))) {
		printf("Breakpoints may not be placed on instructions that can't be single stepped\n");
		return 0;
	}
	return 1;
}

static int find_free_data_bpt(void)
{
	int i;

	for (i = 0; i < nr_wp_slots(); i++) {
		if (!dabr[i].enabled)
			return i;
	}
	printf("Couldn't find free breakpoint register\n");
	return -1;
}

static void print_data_bpts(void)
{
	int i;

	for (i = 0; i < nr_wp_slots(); i++) {
		if (!dabr[i].enabled)
			continue;

		printf("   data   "REG"  [", dabr[i].address);
		if (dabr[i].enabled & 1)
			printf("r");
		if (dabr[i].enabled & 2)
			printf("w");
		printf("]\n");
	}
}

static char *breakpoint_help_string =
    "Breakpoint command usage:\n"
    "b                show breakpoints\n"
    "b <addr> [cnt]   set breakpoint at given instr addr\n"
    "bc               clear all breakpoints\n"
    "bc <n/addr>      clear breakpoint number n or at addr\n"
    "bi <addr> [cnt]  set hardware instr breakpoint (POWER8 only)\n"
    "bd <addr> [cnt]  set hardware data breakpoint\n"
    "";

static void
bpt_cmds(void)
{
	int cmd;
	unsigned long a;
	int i;
	struct bpt *bp;

	cmd = inchar();

	switch (cmd) {
	case 'd': {	/* bd - hardware data breakpoint */
		static const char badaddr[] = "Only kernel addresses are permitted for breakpoints\n";
		int mode;
		if (xmon_is_ro) {
			printf(xmon_ro_msg);
			break;
		}
		if (!ppc_breakpoint_available()) {
			printf("Hardware data breakpoint not supported on this cpu\n");
			break;
		}
		i = find_free_data_bpt();
		if (i < 0)
			break;
		mode = 7;
		cmd = inchar();
		if (cmd == 'r')
			mode = 5;
		else if (cmd == 'w')
			mode = 6;
		else
			termch = cmd;
		dabr[i].address = 0;
		dabr[i].enabled = 0;
		if (scanhex(&dabr[i].address)) {
			if (!is_kernel_addr(dabr[i].address)) {
				printf(badaddr);
				break;
			}
			dabr[i].address &= ~HW_BRK_TYPE_DABR;
			dabr[i].enabled = mode | BP_DABR;
		}

		force_enable_xmon();
		break;
	}

	case 'i':	/* bi - hardware instr breakpoint */
		if (xmon_is_ro) {
			printf(xmon_ro_msg);
			break;
		}
		if (!cpu_has_feature(CPU_FTR_ARCH_207S)) {
			printf("Hardware instruction breakpoint "
			       "not supported on this cpu\n");
			break;
		}
		if (iabr) {
			iabr->enabled &= ~BP_CIABR;
			iabr = NULL;
		}
		if (!scanhex(&a))
			break;
		if (!check_bp_loc(a))
			break;
		bp = new_breakpoint(a);
		if (bp != NULL) {
			bp->enabled |= BP_CIABR;
			iabr = bp;
			force_enable_xmon();
		}
		break;

	case 'c':
		if (!scanhex(&a)) {
			/* clear all breakpoints */
			for (i = 0; i < NBPTS; ++i)
				bpts[i].enabled = 0;
			iabr = NULL;
			for (i = 0; i < nr_wp_slots(); i++)
				dabr[i].enabled = 0;

			printf("All breakpoints cleared\n");
			break;
		}

		if (a <= NBPTS && a >= 1) {
			/* assume a breakpoint number */
			bp = &bpts[a-1];	/* bp nums are 1 based */
		} else {
			/* assume a breakpoint address */
			bp = at_breakpoint(a);
			if (bp == NULL) {
				printf("No breakpoint at %lx\n", a);
				break;
			}
		}

		printf("Cleared breakpoint %tx (", BP_NUM(bp));
		xmon_print_symbol(bp->address, " ", ")\n");
		bp->enabled = 0;
		break;

	default:
		termch = cmd;
		cmd = skipbl();
		if (cmd == '?') {
			printf(breakpoint_help_string);
			break;
		}
		termch = cmd;

		if (xmon_is_ro || !scanhex(&a)) {
			/* print all breakpoints */
			printf("   type            address\n");
			print_data_bpts();
			for (bp = bpts; bp < &bpts[NBPTS]; ++bp) {
				if (!bp->enabled)
					continue;
				printf("%tx %s   ", BP_NUM(bp),
				    (bp->enabled & BP_CIABR) ? "inst": "trap");
				xmon_print_symbol(bp->address, "  ", "\n");
			}
			break;
		}

		if (!check_bp_loc(a))
			break;
		bp = new_breakpoint(a);
		if (bp != NULL) {
			bp->enabled |= BP_TRAP;
			force_enable_xmon();
		}
		break;
	}
}

/* Very cheap human name for vector lookup. */
static
const char *getvecname(unsigned long vec)
{
	char *ret;

	switch (vec) {
	case 0x100:	ret = "(System Reset)"; break;
	case 0x200:	ret = "(Machine Check)"; break;
	case 0x300:	ret = "(Data Access)"; break;
	case 0x380:
		if (radix_enabled())
			ret = "(Data Access Out of Range)";
		else
			ret = "(Data SLB Access)";
		break;
	case 0x400:	ret = "(Instruction Access)"; break;
	case 0x480:
		if (radix_enabled())
			ret = "(Instruction Access Out of Range)";
		else
			ret = "(Instruction SLB Access)";
		break;
	case 0x500:	ret = "(Hardware Interrupt)"; break;
	case 0x600:	ret = "(Alignment)"; break;
	case 0x700:	ret = "(Program Check)"; break;
	case 0x800:	ret = "(FPU Unavailable)"; break;
	case 0x900:	ret = "(Decrementer)"; break;
	case 0x980:	ret = "(Hypervisor Decrementer)"; break;
	case 0xa00:	ret = "(Doorbell)"; break;
	case 0xc00:	ret = "(System Call)"; break;
	case 0xd00:	ret = "(Single Step)"; break;
	case 0xe40:	ret = "(Emulation Assist)"; break;
	case 0xe60:	ret = "(HMI)"; break;
	case 0xe80:	ret = "(Hypervisor Doorbell)"; break;
	case 0xf00:	ret = "(Performance Monitor)"; break;
	case 0xf20:	ret = "(Altivec Unavailable)"; break;
	case 0x1300:	ret = "(Instruction Breakpoint)"; break;
	case 0x1500:	ret = "(Denormalisation)"; break;
	case 0x1700:	ret = "(Altivec Assist)"; break;
	case 0x3000:	ret = "(System Call Vectored)"; break;
	default: ret = "";
	}
	return ret;
}

static void get_function_bounds(unsigned long pc, unsigned long *startp,
				unsigned long *endp)
{
	unsigned long size, offset;
	const char *name;

	*startp = *endp = 0;
	if (pc == 0)
		return;
	if (setjmp(bus_error_jmp) == 0) {
		catch_memory_errors = 1;
		sync();
		name = kallsyms_lookup(pc, &size, &offset, NULL, tmpstr);
		if (name != NULL) {
			*startp = pc - offset;
			*endp = pc - offset + size;
		}
		sync();
	}
	catch_memory_errors = 0;
}

#define LRSAVE_OFFSET		(STACK_FRAME_LR_SAVE * sizeof(unsigned long))

static void xmon_show_stack(unsigned long sp, unsigned long lr,
			    unsigned long pc)
{
	int max_to_print = 64;
	unsigned long ip;
	unsigned long newsp;
	unsigned long marker;
	struct pt_regs regs;

	while (max_to_print--) {
		if (!is_kernel_addr(sp)) {
			if (sp != 0)
				printf("SP (%lx) is in userspace\n", sp);
			break;
		}

		if (!mread(sp + LRSAVE_OFFSET, &ip, sizeof(unsigned long))
		    || !mread(sp, &newsp, sizeof(unsigned long))) {
			printf("Couldn't read stack frame at %lx\n", sp);
			break;
		}

		/*
		 * For the first stack frame, try to work out if
		 * LR and/or the saved LR value in the bottommost
		 * stack frame are valid.
		 */
		if ((pc | lr) != 0) {
			unsigned long fnstart, fnend;
			unsigned long nextip;
			int printip = 1;

			get_function_bounds(pc, &fnstart, &fnend);
			nextip = 0;
			if (newsp > sp)
				mread(newsp + LRSAVE_OFFSET, &nextip,
				      sizeof(unsigned long));
			if (lr == ip) {
				if (!is_kernel_addr(lr)
				    || (fnstart <= lr && lr < fnend))
					printip = 0;
			} else if (lr == nextip) {
				printip = 0;
			} else if (is_kernel_addr(lr)
				   && !(fnstart <= lr && lr < fnend)) {
				printf("[link register   ] ");
				xmon_print_symbol(lr, " ", "\n");
			}
			if (printip) {
				printf("["REG"] ", sp);
				xmon_print_symbol(ip, " ", " (unreliable)\n");
			}
			pc = lr = 0;

		} else {
			printf("["REG"] ", sp);
			xmon_print_symbol(ip, " ", "\n");
		}

		/* Look for "regs" marker to see if this is
		   an exception frame. */
		if (mread(sp + STACK_INT_FRAME_MARKER, &marker, sizeof(unsigned long))
		    && marker == STACK_FRAME_REGS_MARKER) {
			if (mread(sp + STACK_INT_FRAME_REGS, &regs, sizeof(regs)) != sizeof(regs)) {
				printf("Couldn't read registers at %lx\n",
				       sp + STACK_INT_FRAME_REGS);
				break;
			}
			printf("---- Exception: %lx %s at ", regs.trap,
			       getvecname(TRAP(&regs)));
			pc = regs.nip;
			lr = regs.link;
			xmon_print_symbol(pc, " ", "\n");
		}

		if (newsp == 0)
			break;

		sp = newsp;
	}
}

static void backtrace(struct pt_regs *excp)
{
	unsigned long sp;

	if (scanhex(&sp))
		xmon_show_stack(sp, 0, 0);
	else
		xmon_show_stack(excp->gpr[1], excp->link, excp->nip);
	scannl();
}

static void print_bug_trap(struct pt_regs *regs)
{
#ifdef CONFIG_BUG
	const struct bug_entry *bug;
	unsigned long addr;

	if (user_mode(regs))
		return;
	addr = regs->nip;	/* address of trap instruction */
	if (!is_kernel_addr(addr))
		return;
	bug = find_bug(regs->nip);
	if (bug == NULL)
		return;
	if (is_warning_bug(bug))
		return;

#ifdef CONFIG_DEBUG_BUGVERBOSE
	printf("kernel BUG at %s:%u!\n",
	       (char *)bug + bug->file_disp, bug->line);
#else
	printf("kernel BUG at %px!\n", (void *)bug + bug->bug_addr_disp);
#endif
#endif /* CONFIG_BUG */
}

static void excprint(struct pt_regs *fp)
{
	unsigned long trap;

#ifdef CONFIG_SMP
	printf("cpu 0x%x: ", smp_processor_id());
#endif /* CONFIG_SMP */

	trap = TRAP(fp);
	printf("Vector: %lx %s at [%px]\n", fp->trap, getvecname(trap), fp);
	printf("    pc: ");
	xmon_print_symbol(fp->nip, ": ", "\n");

	printf("    lr: ");
	xmon_print_symbol(fp->link, ": ", "\n");

	printf("    sp: %lx\n", fp->gpr[1]);
	printf("   msr: %lx\n", fp->msr);

	if (trap == INTERRUPT_DATA_STORAGE ||
	    trap == INTERRUPT_DATA_SEGMENT ||
	    trap == INTERRUPT_ALIGNMENT ||
	    trap == INTERRUPT_MACHINE_CHECK) {
		printf("   dar: %lx\n", fp->dar);
		if (trap != INTERRUPT_DATA_SEGMENT)
			printf(" dsisr: %lx\n", fp->dsisr);
	}

	printf("  current = 0x%px\n", current);
#ifdef CONFIG_PPC64
	printf("  paca    = 0x%px\t irqmask: 0x%02x\t irq_happened: 0x%02x\n",
	       local_paca, local_paca->irq_soft_mask, local_paca->irq_happened);
#endif
	if (current) {
		printf("    pid   = %d, comm = %s\n",
		       current->pid, current->comm);
	}

	if (trap == INTERRUPT_PROGRAM)
		print_bug_trap(fp);

	printf(linux_banner);
}

static void prregs(struct pt_regs *fp)
{
	int n, trap;
	unsigned long base;
	struct pt_regs regs;

	if (scanhex(&base)) {
		if (setjmp(bus_error_jmp) == 0) {
			catch_memory_errors = 1;
			sync();
			regs = *(struct pt_regs *)base;
			sync();
			__delay(200);
		} else {
			catch_memory_errors = 0;
			printf("*** Error reading registers from "REG"\n",
			       base);
			return;
		}
		catch_memory_errors = 0;
		fp = &regs;
	}

#ifdef CONFIG_PPC64
#define R_PER_LINE 2
#else
#define R_PER_LINE 4
#endif

	for (n = 0; n < 32; ++n) {
		printf("R%.2d = "REG"%s", n, fp->gpr[n],
			(n % R_PER_LINE) == R_PER_LINE - 1 ? "\n" : "   ");
	}

	printf("pc  = ");
	xmon_print_symbol(fp->nip, " ", "\n");
	if (!trap_is_syscall(fp) && cpu_has_feature(CPU_FTR_CFAR)) {
		printf("cfar= ");
		xmon_print_symbol(fp->orig_gpr3, " ", "\n");
	}
	printf("lr  = ");
	xmon_print_symbol(fp->link, " ", "\n");
	printf("msr = "REG"   cr  = %.8lx\n", fp->msr, fp->ccr);
	printf("ctr = "REG"   xer = "REG"   trap = %4lx\n",
	       fp->ctr, fp->xer, fp->trap);
	trap = TRAP(fp);
	if (trap == INTERRUPT_DATA_STORAGE ||
	    trap == INTERRUPT_DATA_SEGMENT ||
	    trap == INTERRUPT_ALIGNMENT)
		printf("dar = "REG"   dsisr = %.8lx\n", fp->dar, fp->dsisr);
}

static void cacheflush(void)
{
	int cmd;
	unsigned long nflush;

	cmd = inchar();
	if (cmd != 'i')
		termch = cmd;
	scanhex((void *)&adrs);
	if (termch != '\n')
		termch = 0;
	nflush = 1;
	scanhex(&nflush);
	nflush = (nflush + L1_CACHE_BYTES - 1) / L1_CACHE_BYTES;
	if (setjmp(bus_error_jmp) == 0) {
		catch_memory_errors = 1;
		sync();

		if (cmd != 'i' || IS_ENABLED(CONFIG_PPC_BOOK3S_64)) {
			for (; nflush > 0; --nflush, adrs += L1_CACHE_BYTES)
				cflush((void *) adrs);
		} else {
			for (; nflush > 0; --nflush, adrs += L1_CACHE_BYTES)
				cinval((void *) adrs);
		}
		sync();
		/* wait a little while to see if we get a machine check */
		__delay(200);
	}
	catch_memory_errors = 0;
}

extern unsigned long xmon_mfspr(int spr, unsigned long default_value);
extern void xmon_mtspr(int spr, unsigned long value);

static int
read_spr(int n, unsigned long *vp)
{
	unsigned long ret = -1UL;
	int ok = 0;

	if (setjmp(bus_error_jmp) == 0) {
		catch_spr_faults = 1;
		sync();

		ret = xmon_mfspr(n, *vp);

		sync();
		*vp = ret;
		ok = 1;
	}
	catch_spr_faults = 0;

	return ok;
}

static void
write_spr(int n, unsigned long val)
{
	if (xmon_is_ro) {
		printf(xmon_ro_msg);
		return;
	}

	if (setjmp(bus_error_jmp) == 0) {
		catch_spr_faults = 1;
		sync();

		xmon_mtspr(n, val);

		sync();
	} else {
		printf("SPR 0x%03x (%4d) Faulted during write\n", n, n);
	}
	catch_spr_faults = 0;
}

static void dump_206_sprs(void)
{
#ifdef CONFIG_PPC64
	if (!cpu_has_feature(CPU_FTR_ARCH_206))
		return;

	/* Actually some of these pre-date 2.06, but whatever */

	printf("srr0   = %.16lx  srr1  = %.16lx dsisr  = %.8lx\n",
		mfspr(SPRN_SRR0), mfspr(SPRN_SRR1), mfspr(SPRN_DSISR));
	printf("dscr   = %.16lx  ppr   = %.16lx pir    = %.8lx\n",
		mfspr(SPRN_DSCR), mfspr(SPRN_PPR), mfspr(SPRN_PIR));
	printf("amr    = %.16lx  uamor = %.16lx\n",
		mfspr(SPRN_AMR), mfspr(SPRN_UAMOR));

	if (!(mfmsr() & MSR_HV))
		return;

	printf("sdr1   = %.16lx  hdar  = %.16lx hdsisr = %.8lx\n",
		mfspr(SPRN_SDR1), mfspr(SPRN_HDAR), mfspr(SPRN_HDSISR));
	printf("hsrr0  = %.16lx hsrr1  = %.16lx hdec   = %.16lx\n",
		mfspr(SPRN_HSRR0), mfspr(SPRN_HSRR1), mfspr(SPRN_HDEC));
	printf("lpcr   = %.16lx  pcr   = %.16lx lpidr  = %.8lx\n",
		mfspr(SPRN_LPCR), mfspr(SPRN_PCR), mfspr(SPRN_LPID));
	printf("hsprg0 = %.16lx hsprg1 = %.16lx amor   = %.16lx\n",
		mfspr(SPRN_HSPRG0), mfspr(SPRN_HSPRG1), mfspr(SPRN_AMOR));
	printf("dabr   = %.16lx dabrx  = %.16lx\n",
		mfspr(SPRN_DABR), mfspr(SPRN_DABRX));
#endif
}

static void dump_207_sprs(void)
{
#ifdef CONFIG_PPC64
	unsigned long msr;

	if (!cpu_has_feature(CPU_FTR_ARCH_207S))
		return;

	printf("dpdes  = %.16lx  tir   = %.16lx cir    = %.8lx\n",
		mfspr(SPRN_DPDES), mfspr(SPRN_TIR), mfspr(SPRN_CIR));

	printf("fscr   = %.16lx  tar   = %.16lx pspb   = %.8lx\n",
		mfspr(SPRN_FSCR), mfspr(SPRN_TAR), mfspr(SPRN_PSPB));

	msr = mfmsr();
	if (msr & MSR_TM) {
		/* Only if TM has been enabled in the kernel */
		printf("tfhar  = %.16lx  tfiar = %.16lx texasr = %.16lx\n",
			mfspr(SPRN_TFHAR), mfspr(SPRN_TFIAR),
			mfspr(SPRN_TEXASR));
	}

	printf("mmcr0  = %.16lx  mmcr1 = %.16lx mmcr2  = %.16lx\n",
		mfspr(SPRN_MMCR0), mfspr(SPRN_MMCR1), mfspr(SPRN_MMCR2));
	printf("pmc1   = %.8lx pmc2 = %.8lx  pmc3 = %.8lx  pmc4   = %.8lx\n",
		mfspr(SPRN_PMC1), mfspr(SPRN_PMC2),
		mfspr(SPRN_PMC3), mfspr(SPRN_PMC4));
	printf("mmcra  = %.16lx   siar = %.16lx pmc5   = %.8lx\n",
		mfspr(SPRN_MMCRA), mfspr(SPRN_SIAR), mfspr(SPRN_PMC5));
	printf("sdar   = %.16lx   sier = %.16lx pmc6   = %.8lx\n",
		mfspr(SPRN_SDAR), mfspr(SPRN_SIER), mfspr(SPRN_PMC6));
	printf("ebbhr  = %.16lx  ebbrr = %.16lx bescr  = %.16lx\n",
		mfspr(SPRN_EBBHR), mfspr(SPRN_EBBRR), mfspr(SPRN_BESCR));
	printf("iamr   = %.16lx\n", mfspr(SPRN_IAMR));

	if (!(msr & MSR_HV))
		return;

	printf("hfscr  = %.16lx  dhdes = %.16lx rpr    = %.16lx\n",
		mfspr(SPRN_HFSCR), mfspr(SPRN_DHDES), mfspr(SPRN_RPR));
	printf("dawr0  = %.16lx dawrx0 = %.16lx\n",
	       mfspr(SPRN_DAWR0), mfspr(SPRN_DAWRX0));
	if (nr_wp_slots() > 1) {
		printf("dawr1  = %.16lx dawrx1 = %.16lx\n",
		       mfspr(SPRN_DAWR1), mfspr(SPRN_DAWRX1));
	}
	printf("ciabr  = %.16lx\n", mfspr(SPRN_CIABR));
#endif
}

static void dump_300_sprs(void)
{
#ifdef CONFIG_PPC64
	bool hv = mfmsr() & MSR_HV;

	if (!cpu_has_feature(CPU_FTR_ARCH_300))
		return;

	if (cpu_has_feature(CPU_FTR_P9_TIDR)) {
		printf("pidr   = %.16lx  tidr  = %.16lx\n",
			mfspr(SPRN_PID), mfspr(SPRN_TIDR));
	} else {
		printf("pidr   = %.16lx\n",
			mfspr(SPRN_PID));
	}

	printf("psscr  = %.16lx\n",
		hv ? mfspr(SPRN_PSSCR) : mfspr(SPRN_PSSCR_PR));

	if (!hv)
		return;

	printf("ptcr   = %.16lx  asdr  = %.16lx\n",
		mfspr(SPRN_PTCR), mfspr(SPRN_ASDR));
#endif
}

static void dump_310_sprs(void)
{
#ifdef CONFIG_PPC64
	if (!cpu_has_feature(CPU_FTR_ARCH_31))
		return;

	printf("mmcr3  = %.16lx, sier2  = %.16lx, sier3  = %.16lx\n",
		mfspr(SPRN_MMCR3), mfspr(SPRN_SIER2), mfspr(SPRN_SIER3));

#endif
}

static void dump_one_spr(int spr, bool show_unimplemented)
{
	unsigned long val;

	val = 0xdeadbeef;
	if (!read_spr(spr, &val)) {
		printf("SPR 0x%03x (%4d) Faulted during read\n", spr, spr);
		return;
	}

	if (val == 0xdeadbeef) {
		/* Looks like read was a nop, confirm */
		val = 0x0badcafe;
		if (!read_spr(spr, &val)) {
			printf("SPR 0x%03x (%4d) Faulted during read\n", spr, spr);
			return;
		}

		if (val == 0x0badcafe) {
			if (show_unimplemented)
				printf("SPR 0x%03x (%4d) Unimplemented\n", spr, spr);
			return;
		}
	}

	printf("SPR 0x%03x (%4d) = 0x%lx\n", spr, spr, val);
}

static void super_regs(void)
{
	static unsigned long regno;
	int cmd;
	int spr;

	cmd = skipbl();

	switch (cmd) {
	case '\n': {
		unsigned long sp, toc;
		asm("mr %0,1" : "=r" (sp) :);
		asm("mr %0,2" : "=r" (toc) :);

		printf("msr    = "REG"  sprg0 = "REG"\n",
		       mfmsr(), mfspr(SPRN_SPRG0));
		printf("pvr    = "REG"  sprg1 = "REG"\n",
		       mfspr(SPRN_PVR), mfspr(SPRN_SPRG1));
		printf("dec    = "REG"  sprg2 = "REG"\n",
		       mfspr(SPRN_DEC), mfspr(SPRN_SPRG2));
		printf("sp     = "REG"  sprg3 = "REG"\n", sp, mfspr(SPRN_SPRG3));
		printf("toc    = "REG"  dar   = "REG"\n", toc, mfspr(SPRN_DAR));

		dump_206_sprs();
		dump_207_sprs();
		dump_300_sprs();
		dump_310_sprs();

		return;
	}
	case 'w': {
		unsigned long val;
		scanhex(&regno);
		val = 0;
		read_spr(regno, &val);
		scanhex(&val);
		write_spr(regno, val);
		dump_one_spr(regno, true);
		break;
	}
	case 'r':
		scanhex(&regno);
		dump_one_spr(regno, true);
		break;
	case 'a':
		/* dump ALL SPRs */
		for (spr = 1; spr < 1024; ++spr)
			dump_one_spr(spr, false);
		break;
	}

	scannl();
}

/*
 * Stuff for reading and writing memory safely
 */
static int
mread(unsigned long adrs, void *buf, int size)
{
	volatile int n;
	char *p, *q;

	n = 0;
	if (setjmp(bus_error_jmp) == 0) {
		catch_memory_errors = 1;
		sync();
		p = (char *)adrs;
		q = (char *)buf;
		switch (size) {
		case 2:
			*(u16 *)q = *(u16 *)p;
			break;
		case 4:
			*(u32 *)q = *(u32 *)p;
			break;
		case 8:
			*(u64 *)q = *(u64 *)p;
			break;
		default:
			for( ; n < size; ++n) {
				*q++ = *p++;
				sync();
			}
		}
		sync();
		/* wait a little while to see if we get a machine check */
		__delay(200);
		n = size;
	}
	catch_memory_errors = 0;
	return n;
}

static int
mwrite(unsigned long adrs, void *buf, int size)
{
	volatile int n;
	char *p, *q;

	n = 0;

	if (xmon_is_ro) {
		printf(xmon_ro_msg);
		return n;
	}

	if (setjmp(bus_error_jmp) == 0) {
		catch_memory_errors = 1;
		sync();
		p = (char *) adrs;
		q = (char *) buf;
		switch (size) {
		case 2:
			*(u16 *)p = *(u16 *)q;
			break;
		case 4:
			*(u32 *)p = *(u32 *)q;
			break;
		case 8:
			*(u64 *)p = *(u64 *)q;
			break;
		default:
			for ( ; n < size; ++n) {
				*p++ = *q++;
				sync();
			}
		}
		sync();
		/* wait a little while to see if we get a machine check */
		__delay(200);
		n = size;
	} else {
		printf("*** Error writing address "REG"\n", adrs + n);
	}
	catch_memory_errors = 0;
	return n;
}

static int
mread_instr(unsigned long adrs, ppc_inst_t *instr)
{
	volatile int n;

	n = 0;
	if (setjmp(bus_error_jmp) == 0) {
		catch_memory_errors = 1;
		sync();
		*instr = ppc_inst_read((u32 *)adrs);
		sync();
		/* wait a little while to see if we get a machine check */
		__delay(200);
		n = ppc_inst_len(*instr);
	}
	catch_memory_errors = 0;
	return n;
}

static int fault_type;
static int fault_except;
static char *fault_chars[] = { "--", "**", "##" };

static int handle_fault(struct pt_regs *regs)
{
	fault_except = TRAP(regs);
	switch (TRAP(regs)) {
	case 0x200:
		fault_type = 0;
		break;
	case 0x300:
	case 0x380:
		fault_type = 1;
		break;
	default:
		fault_type = 2;
	}

	longjmp(bus_error_jmp, 1);

	return 0;
}

#define SWAP(a, b, t)	((t) = (a), (a) = (b), (b) = (t))

static void
byterev(unsigned char *val, int size)
{
	int t;
	
	switch (size) {
	case 2:
		SWAP(val[0], val[1], t);
		break;
	case 4:
		SWAP(val[0], val[3], t);
		SWAP(val[1], val[2], t);
		break;
	case 8: /* is there really any use for this? */
		SWAP(val[0], val[7], t);
		SWAP(val[1], val[6], t);
		SWAP(val[2], val[5], t);
		SWAP(val[3], val[4], t);
		break;
	}
}

static int brev;
static int mnoread;

static char *memex_help_string =
    "Memory examine command usage:\n"
    "m [addr] [flags] examine/change memory\n"
    "  addr is optional.  will start where left off.\n"
    "  flags may include chars from this set:\n"
    "    b   modify by bytes (default)\n"
    "    w   modify by words (2 byte)\n"
    "    l   modify by longs (4 byte)\n"
    "    d   modify by doubleword (8 byte)\n"
    "    r   toggle reverse byte order mode\n"
    "    n   do not read memory (for i/o spaces)\n"
    "    .   ok to read (default)\n"
    "NOTE: flags are saved as defaults\n"
    "";

static char *memex_subcmd_help_string =
    "Memory examine subcommands:\n"
    "  hexval   write this val to current location\n"
    "  'string' write chars from string to this location\n"
    "  '        increment address\n"
    "  ^        decrement address\n"
    "  /        increment addr by 0x10.  //=0x100, ///=0x1000, etc\n"
    "  \\        decrement addr by 0x10.  \\\\=0x100, \\\\\\=0x1000, etc\n"
    "  `        clear no-read flag\n"
    "  ;        stay at this addr\n"
    "  v        change to byte mode\n"
    "  w        change to word (2 byte) mode\n"
    "  l        change to long (4 byte) mode\n"
    "  u        change to doubleword (8 byte) mode\n"
    "  m addr   change current addr\n"
    "  n        toggle no-read flag\n"
    "  r        toggle byte reverse flag\n"
    "  < count  back up count bytes\n"
    "  > count  skip forward count bytes\n"
    "  x        exit this mode\n"
    "";

static void
memex(void)
{
	int cmd, inc, i, nslash;
	unsigned long n;
	unsigned char val[16];

	scanhex((void *)&adrs);
	cmd = skipbl();
	if (cmd == '?') {
		printf(memex_help_string);
		return;
	} else {
		termch = cmd;
	}
	last_cmd = "m\n";
	while ((cmd = skipbl()) != '\n') {
		switch( cmd ){
		case 'b':	size = 1;	break;
		case 'w':	size = 2;	break;
		case 'l':	size = 4;	break;
		case 'd':	size = 8;	break;
		case 'r': 	brev = !brev;	break;
		case 'n':	mnoread = 1;	break;
		case '.':	mnoread = 0;	break;
		}
	}
	if( size <= 0 )
		size = 1;
	else if( size > 8 )
		size = 8;
	for(;;){
		if (!mnoread)
			n = mread(adrs, val, size);
		printf(REG"%c", adrs, brev? 'r': ' ');
		if (!mnoread) {
			if (brev)
				byterev(val, size);
			putchar(' ');
			for (i = 0; i < n; ++i)
				printf("%.2x", val[i]);
			for (; i < size; ++i)
				printf("%s", fault_chars[fault_type]);
		}
		putchar(' ');
		inc = size;
		nslash = 0;
		for(;;){
			if( scanhex(&n) ){
				for (i = 0; i < size; ++i)
					val[i] = n >> (i * 8);
				if (!brev)
					byterev(val, size);
				mwrite(adrs, val, size);
				inc = size;
			}
			cmd = skipbl();
			if (cmd == '\n')
				break;
			inc = 0;
			switch (cmd) {
			case '\'':
				for(;;){
					n = inchar();
					if( n == '\\' )
						n = bsesc();
					else if( n == '\'' )
						break;
					for (i = 0; i < size; ++i)
						val[i] = n >> (i * 8);
					if (!brev)
						byterev(val, size);
					mwrite(adrs, val, size);
					adrs += size;
				}
				adrs -= size;
				inc = size;
				break;
			case ',':
				adrs += size;
				break;
			case '.':
				mnoread = 0;
				break;
			case ';':
				break;
			case 'x':
			case EOF:
				scannl();
				return;
			case 'b':
			case 'v':
				size = 1;
				break;
			case 'w':
				size = 2;
				break;
			case 'l':
				size = 4;
				break;
			case 'u':
				size = 8;
				break;
			case '^':
				adrs -= size;
				break;
			case '/':
				if (nslash > 0)
					adrs -= 1 << nslash;
				else
					nslash = 0;
				nslash += 4;
				adrs += 1 << nslash;
				break;
			case '\\':
				if (nslash < 0)
					adrs += 1 << -nslash;
				else
					nslash = 0;
				nslash -= 4;
				adrs -= 1 << -nslash;
				break;
			case 'm':
				scanhex((void *)&adrs);
				break;
			case 'n':
				mnoread = 1;
				break;
			case 'r':
				brev = !brev;
				break;
			case '<':
				n = size;
				scanhex(&n);
				adrs -= n;
				break;
			case '>':
				n = size;
				scanhex(&n);
				adrs += n;
				break;
			case '?':
				printf(memex_subcmd_help_string);
				break;
			}
		}
		adrs += inc;
	}
}

static int
bsesc(void)
{
	int c;

	c = inchar();
	switch( c ){
	case 'n':	c = '\n';	break;
	case 'r':	c = '\r';	break;
	case 'b':	c = '\b';	break;
	case 't':	c = '\t';	break;
	}
	return c;
}

static void xmon_rawdump (unsigned long adrs, long ndump)
{
	long n, m, r, nr;
	unsigned char temp[16];

	for (n = ndump; n > 0;) {
		r = n < 16? n: 16;
		nr = mread(adrs, temp, r);
		adrs += nr;
		for (m = 0; m < r; ++m) {
			if (m < nr)
				printf("%.2x", temp[m]);
			else
				printf("%s", fault_chars[fault_type]);
		}
		n -= r;
		if (nr < r)
			break;
	}
	printf("\n");
}

static void dump_tracing(void)
{
	int c;

	c = inchar();
	if (c == 'c')
		ftrace_dump(DUMP_ORIG);
	else
		ftrace_dump(DUMP_ALL);
}

#ifdef CONFIG_PPC64
static void dump_one_paca(int cpu)
{
	struct paca_struct *p;
#ifdef CONFIG_PPC_64S_HASH_MMU
	int i = 0;
#endif

	if (setjmp(bus_error_jmp) != 0) {
		printf("*** Error dumping paca for cpu 0x%x!\n", cpu);
		return;
	}

	catch_memory_errors = 1;
	sync();

	p = paca_ptrs[cpu];

	printf("paca for cpu 0x%x @ %px:\n", cpu, p);

	printf(" %-*s = %s\n", 25, "possible", str_yes_no(cpu_possible(cpu)));
	printf(" %-*s = %s\n", 25, "present", str_yes_no(cpu_present(cpu)));
	printf(" %-*s = %s\n", 25, "online", str_yes_no(cpu_online(cpu)));

#define DUMP(paca, name, format)				\
	printf(" %-*s = "format"\t(0x%lx)\n", 25, #name, 18, paca->name, \
		offsetof(struct paca_struct, name));

	DUMP(p, lock_token, "%#-*x");
	DUMP(p, paca_index, "%#-*x");
#ifndef CONFIG_PPC_KERNEL_PCREL
	DUMP(p, kernel_toc, "%#-*llx");
#endif
	DUMP(p, kernelbase, "%#-*llx");
	DUMP(p, kernel_msr, "%#-*llx");
	DUMP(p, emergency_sp, "%-*px");
#ifdef CONFIG_PPC_BOOK3S_64
	DUMP(p, nmi_emergency_sp, "%-*px");
	DUMP(p, mc_emergency_sp, "%-*px");
	DUMP(p, in_nmi, "%#-*x");
	DUMP(p, in_mce, "%#-*x");
	DUMP(p, hmi_event_available, "%#-*x");
#endif
	DUMP(p, data_offset, "%#-*llx");
	DUMP(p, hw_cpu_id, "%#-*x");
	DUMP(p, cpu_start, "%#-*x");
	DUMP(p, kexec_state, "%#-*x");
#ifdef CONFIG_PPC_BOOK3S_64
#ifdef CONFIG_PPC_64S_HASH_MMU
	if (!early_radix_enabled()) {
		for (i = 0; i < SLB_NUM_BOLTED; i++) {
			u64 esid, vsid;

			if (!p->slb_shadow_ptr)
				continue;

			esid = be64_to_cpu(p->slb_shadow_ptr->save_area[i].esid);
			vsid = be64_to_cpu(p->slb_shadow_ptr->save_area[i].vsid);

			if (esid || vsid) {
				printf(" %-*s[%d] = 0x%016llx 0x%016llx\n",
				       22, "slb_shadow", i, esid, vsid);
			}
		}
		DUMP(p, vmalloc_sllp, "%#-*x");
		DUMP(p, stab_rr, "%#-*x");
		DUMP(p, slb_used_bitmap, "%#-*x");
		DUMP(p, slb_kern_bitmap, "%#-*x");

		if (!early_cpu_has_feature(CPU_FTR_ARCH_300)) {
			DUMP(p, slb_cache_ptr, "%#-*x");
			for (i = 0; i < SLB_CACHE_ENTRIES; i++)
				printf(" %-*s[%d] = 0x%016x\n",
				       22, "slb_cache", i, p->slb_cache[i]);
		}
	}
#endif

	DUMP(p, rfi_flush_fallback_area, "%-*px");
#endif
	DUMP(p, dscr_default, "%#-*llx");
#ifdef CONFIG_PPC_BOOK3E_64
	DUMP(p, pgd, "%-*px");
	DUMP(p, kernel_pgd, "%-*px");
	DUMP(p, tcd_ptr, "%-*px");
	DUMP(p, mc_kstack, "%-*px");
	DUMP(p, crit_kstack, "%-*px");
	DUMP(p, dbg_kstack, "%-*px");
#endif
	DUMP(p, __current, "%-*px");
	DUMP(p, kstack, "%#-*llx");
	printf(" %-*s = 0x%016llx\n", 25, "kstack_base", p->kstack & ~(THREAD_SIZE - 1));
#ifdef CONFIG_STACKPROTECTOR
	DUMP(p, canary, "%#-*lx");
#endif
	DUMP(p, saved_r1, "%#-*llx");
#ifdef CONFIG_PPC_BOOK3E_64
	DUMP(p, trap_save, "%#-*x");
#endif
	DUMP(p, irq_soft_mask, "%#-*x");
	DUMP(p, irq_happened, "%#-*x");
#ifdef CONFIG_MMIOWB
	DUMP(p, mmiowb_state.nesting_count, "%#-*x");
	DUMP(p, mmiowb_state.mmiowb_pending, "%#-*x");
#endif
	DUMP(p, irq_work_pending, "%#-*x");
	DUMP(p, sprg_vdso, "%#-*llx");

#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
	DUMP(p, tm_scratch, "%#-*llx");
#endif

#ifdef CONFIG_PPC_POWERNV
	DUMP(p, idle_state, "%#-*lx");
	if (!early_cpu_has_feature(CPU_FTR_ARCH_300)) {
		DUMP(p, thread_idle_state, "%#-*x");
		DUMP(p, subcore_sibling_mask, "%#-*x");
	} else {
#ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
		DUMP(p, requested_psscr, "%#-*llx");
		DUMP(p, dont_stop.counter, "%#-*x");
#endif
	}
#endif

	DUMP(p, accounting.utime, "%#-*lx");
	DUMP(p, accounting.stime, "%#-*lx");
#ifdef CONFIG_ARCH_HAS_SCALED_CPUTIME
	DUMP(p, accounting.utime_scaled, "%#-*lx");
#endif
	DUMP(p, accounting.starttime, "%#-*lx");
	DUMP(p, accounting.starttime_user, "%#-*lx");
#ifdef CONFIG_ARCH_HAS_SCALED_CPUTIME
	DUMP(p, accounting.startspurr, "%#-*lx");
	DUMP(p, accounting.utime_sspurr, "%#-*lx");
#endif
	DUMP(p, accounting.steal_time, "%#-*lx");
#undef DUMP

	catch_memory_errors = 0;
	sync();
}

static void dump_all_pacas(void)
{
	int cpu;

	if (num_possible_cpus() == 0) {
		printf("No possible cpus, use 'dp #' to dump individual cpus\n");
		return;
	}

	for_each_possible_cpu(cpu)
		dump_one_paca(cpu);
}

static void dump_pacas(void)
{
	unsigned long num;
	int c;

	c = inchar();
	if (c == 'a') {
		dump_all_pacas();
		return;
	}

	termch = c;	/* Put c back, it wasn't 'a' */

	if (scanhex(&num) && num < num_possible_cpus())
		dump_one_paca(num);
	else
		dump_one_paca(xmon_owner);
}
#endif

#ifdef CONFIG_PPC_POWERNV
static void dump_one_xive(int cpu)
{
	unsigned int hwid = get_hard_smp_processor_id(cpu);
	bool hv = cpu_has_feature(CPU_FTR_HVMODE);

	if (hv) {
		opal_xive_dump(XIVE_DUMP_TM_HYP, hwid);
		opal_xive_dump(XIVE_DUMP_TM_POOL, hwid);
		opal_xive_dump(XIVE_DUMP_TM_OS, hwid);
		opal_xive_dump(XIVE_DUMP_TM_USER, hwid);
		opal_xive_dump(XIVE_DUMP_VP, hwid);
		opal_xive_dump(XIVE_DUMP_EMU_STATE, hwid);
	}

	if (setjmp(bus_error_jmp) != 0) {
		catch_memory_errors = 0;
		printf("*** Error dumping xive on cpu %d\n", cpu);
		return;
	}

	catch_memory_errors = 1;
	sync();
	xmon_xive_do_dump(cpu);
	sync();
	__delay(200);
	catch_memory_errors = 0;
}

static void dump_all_xives(void)
{
	int cpu;

	if (num_online_cpus() == 0) {
		printf("No possible cpus, use 'dx #' to dump individual cpus\n");
		return;
	}

	for_each_online_cpu(cpu)
		dump_one_xive(cpu);
}

static void dump_xives(void)
{
	unsigned long num;
	int c;

	if (!xive_enabled()) {
		printf("Xive disabled on this system\n");
		return;
	}

	c = inchar();
	if (c == 'a') {
		dump_all_xives();
		return;
	} else if (c == 'i') {
		if (scanhex(&num))
			xmon_xive_get_irq_config(num, NULL);
		else
			xmon_xive_get_irq_all();
		return;
	}

	termch = c;	/* Put c back, it wasn't 'a' */

	if (scanhex(&num) && num < num_possible_cpus())
		dump_one_xive(num);
	else
		dump_one_xive(xmon_owner);
}
#endif /* CONFIG_PPC_POWERNV */

static void dump_by_size(unsigned long addr, long count, int size)
{
	unsigned char temp[16];
	int i, j;
	u64 val;

	count = ALIGN(count, 16);

	for (i = 0; i < count; i += 16, addr += 16) {
		printf(REG, addr);

		if (mread(addr, temp, 16) != 16) {
			printf("\nFaulted reading %d bytes from 0x"REG"\n", 16, addr);
			return;
		}

		for (j = 0; j < 16; j += size) {
			putchar(' ');
			switch (size) {
			case 1: val = temp[j]; break;
			case 2: val = *(u16 *)&temp[j]; break;
			case 4: val = *(u32 *)&temp[j]; break;
			case 8: val = *(u64 *)&temp[j]; break;
			default: val = 0;
			}

			printf("%0*llx", size * 2, val);
		}
		printf("  |");
		for (j = 0; j < 16; ++j) {
			val = temp[j];
			putchar(' ' <= val && val <= '~' ? val : '.');
		}
		printf("|\n");
	}
}

static void
dump(void)
{
	static char last[] = { "d?\n" };
	int c;

	c = inchar();

#ifdef CONFIG_PPC64
	if (c == 'p') {
		xmon_start_pagination();
		dump_pacas();
		xmon_end_pagination();
		return;
	}
#endif
#ifdef CONFIG_PPC_POWERNV
	if (c == 'x') {
		xmon_start_pagination();
		dump_xives();
		xmon_end_pagination();
		return;
	}
#endif

	if (c == 't') {
		dump_tracing();
		return;
	}

	if (c == '\n')
		termch = c;

	scanhex((void *)&adrs);
	if (termch != '\n')
		termch = 0;
	if (c == 'i') {
		scanhex(&nidump);
		if (nidump == 0)
			nidump = 16;
		else if (nidump > MAX_IDUMP)
			nidump = MAX_IDUMP;
		adrs += ppc_inst_dump(adrs, nidump, 1);
		last_cmd = "di\n";
	} else if (c == 'l') {
		dump_log_buf();
	} else if (c == 'o') {
		dump_opal_msglog();
	} else if (c == 'v') {
		/* dump virtual to physical translation */
		show_pte(adrs);
	} else if (c == 'r') {
		scanhex(&ndump);
		if (ndump == 0)
			ndump = 64;
		xmon_rawdump(adrs, ndump);
		adrs += ndump;
		last_cmd = "dr\n";
	} else {
		scanhex(&ndump);
		if (ndump == 0)
			ndump = 64;
		else if (ndump > MAX_DUMP)
			ndump = MAX_DUMP;

		switch (c) {
		case '8':
		case '4':
		case '2':
		case '1':
			ndump = ALIGN(ndump, 16);
			dump_by_size(adrs, ndump, c - '0');
			last[1] = c;
			last_cmd = last;
			break;
		default:
			prdump(adrs, ndump);
			last_cmd = "d\n";
		}

		adrs += ndump;
	}
}

static void
prdump(unsigned long adrs, long ndump)
{
	long n, m, c, r, nr;
	unsigned char temp[16];

	for (n = ndump; n > 0;) {
		printf(REG, adrs);
		putchar(' ');
		r = n < 16? n: 16;
		nr = mread(adrs, temp, r);
		adrs += nr;
		for (m = 0; m < r; ++m) {
			if ((m & (sizeof(long) - 1)) == 0 && m > 0)
				putchar(' ');
			if (m < nr)
				printf("%.2x", temp[m]);
			else
				printf("%s", fault_chars[fault_type]);
		}
		for (; m < 16; ++m) {
			if ((m & (sizeof(long) - 1)) == 0)
				putchar(' ');
			printf("  ");
		}
		printf("  |");
		for (m = 0; m < r; ++m) {
			if (m < nr) {
				c = temp[m];
				putchar(' ' <= c && c <= '~'? c: '.');
			} else
				putchar(' ');
		}
		n -= r;
		for (; m < 16; ++m)
			putchar(' ');
		printf("|\n");
		if (nr < r)
			break;
	}
}

typedef int (*instruction_dump_func)(unsigned long inst, unsigned long addr);

static int
generic_inst_dump(unsigned long adr, long count, int praddr,
			instruction_dump_func dump_func)
{
	int nr, dotted;
	unsigned long first_adr;
	ppc_inst_t inst, last_inst = ppc_inst(0);

	dotted = 0;
	for (first_adr = adr; count > 0; --count, adr += ppc_inst_len(inst)) {
		nr = mread_instr(adr, &inst);
		if (nr == 0) {
			if (praddr) {
				const char *x = fault_chars[fault_type];
				printf(REG"  %s%s%s%s\n", adr, x, x, x, x);
			}
			break;
		}
		if (adr > first_adr && ppc_inst_equal(inst, last_inst)) {
			if (!dotted) {
				printf(" ...\n");
				dotted = 1;
			}
			continue;
		}
		dotted = 0;
		last_inst = inst;
		if (praddr)
			printf(REG"  %08lx", adr, ppc_inst_as_ulong(inst));
		printf("\t");
		if (!ppc_inst_prefixed(inst))
			dump_func(ppc_inst_val(inst), adr);
		else
			dump_func(ppc_inst_as_ulong(inst), adr);
		printf("\n");
	}
	return adr - first_adr;
}

static int
ppc_inst_dump(unsigned long adr, long count, int praddr)
{
	return generic_inst_dump(adr, count, praddr, print_insn_powerpc);
}

void
print_address(unsigned long addr)
{
	xmon_print_symbol(addr, "\t# ", "");
}

static void
dump_log_buf(void)
{
	struct kmsg_dump_iter iter;
	static unsigned char buf[1024];
	size_t len;

	if (setjmp(bus_error_jmp) != 0) {
		printf("Error dumping printk buffer!\n");
		return;
	}

	catch_memory_errors = 1;
	sync();

	kmsg_dump_rewind(&iter);
	xmon_start_pagination();
	while (kmsg_dump_get_line(&iter, false, buf, sizeof(buf), &len)) {
		buf[len] = '\0';
		printf("%s", buf);
	}
	xmon_end_pagination();

	sync();
	/* wait a little while to see if we get a machine check */
	__delay(200);
	catch_memory_errors = 0;
}

#ifdef CONFIG_PPC_POWERNV
static void dump_opal_msglog(void)
{
	unsigned char buf[128];
	ssize_t res;
	volatile loff_t pos = 0;

	if (!firmware_has_feature(FW_FEATURE_OPAL)) {
		printf("Machine is not running OPAL firmware.\n");
		return;
	}

	if (setjmp(bus_error_jmp) != 0) {
		printf("Error dumping OPAL msglog!\n");
		return;
	}

	catch_memory_errors = 1;
	sync();

	xmon_start_pagination();
	while ((res = opal_msglog_copy(buf, pos, sizeof(buf) - 1))) {
		if (res < 0) {
			printf("Error dumping OPAL msglog! Error: %zd\n", res);
			break;
		}
		buf[res] = '\0';
		printf("%s", buf);
		pos += res;
	}
	xmon_end_pagination();

	sync();
	/* wait a little while to see if we get a machine check */
	__delay(200);
	catch_memory_errors = 0;
}
#endif

/*
 * Memory operations - move, set, print differences
 */
static unsigned long mdest;		/* destination address */
static unsigned long msrc;		/* source address */
static unsigned long mval;		/* byte value to set memory to */
static unsigned long mcount;		/* # bytes to affect */
static unsigned long mdiffs;		/* max # differences to print */

static void
memops(int cmd)
{
	scanhex((void *)&mdest);
	if( termch != '\n' )
		termch = 0;
	scanhex((void *)(cmd == 's'? &mval: &msrc));
	if( termch != '\n' )
		termch = 0;
	scanhex((void *)&mcount);
	switch( cmd ){
	case 'm':
		if (xmon_is_ro) {
			printf(xmon_ro_msg);
			break;
		}
		memmove((void *)mdest, (void *)msrc, mcount);
		break;
	case 's':
		if (xmon_is_ro) {
			printf(xmon_ro_msg);
			break;
		}
		memset((void *)mdest, mval, mcount);
		break;
	case 'd':
		if( termch != '\n' )
			termch = 0;
		scanhex((void *)&mdiffs);
		memdiffs((unsigned char *)mdest, (unsigned char *)msrc, mcount, mdiffs);
		break;
	}
}

static void
memdiffs(unsigned char *p1, unsigned char *p2, unsigned nb, unsigned maxpr)
{
	unsigned n, prt;

	prt = 0;
	for( n = nb; n > 0; --n )
		if( *p1++ != *p2++ )
			if( ++prt <= maxpr )
				printf("%px %.2x # %px %.2x\n", p1 - 1,
					p1[-1], p2 - 1, p2[-1]);
	if( prt > maxpr )
		printf("Total of %d differences\n", prt);
}

static unsigned mend;
static unsigned mask;

static void
memlocate(void)
{
	unsigned a, n;
	unsigned char val[4];

	last_cmd = "ml";
	scanhex((void *)&mdest);
	if (termch != '\n') {
		termch = 0;
		scanhex((void *)&mend);
		if (termch != '\n') {
			termch = 0;
			scanhex((void *)&mval);
			mask = ~0;
			if (termch != '\n') termch = 0;
			scanhex((void *)&mask);
		}
	}
	n = 0;
	for (a = mdest; a < mend; a += 4) {
		if (mread(a, val, 4) == 4
			&& ((GETWORD(val) ^ mval) & mask) == 0) {
			printf("%.16x:  %.16x\n", a, GETWORD(val));
			if (++n >= 10)
				break;
		}
	}
}

static unsigned long mskip = 0x1000;
static unsigned long mlim = 0xffffffff;

static void
memzcan(void)
{
	unsigned char v;
	unsigned a;
	int ok, ook;

	scanhex(&mdest);
	if (termch != '\n') termch = 0;
	scanhex(&mskip);
	if (termch != '\n') termch = 0;
	scanhex(&mlim);
	ook = 0;
	for (a = mdest; a < mlim; a += mskip) {
		ok = mread(a, &v, 1);
		if (ok && !ook) {
			printf("%.8x .. ", a);
		} else if (!ok && ook)
			printf("%.8lx\n", a - mskip);
		ook = ok;
		if (a + mskip < a)
			break;
	}
	if (ook)
		printf("%.8lx\n", a - mskip);
}

static void show_task(struct task_struct *volatile tsk)
{
	unsigned int p_state = READ_ONCE(tsk->__state);
	char state;

	/*
	 * Cloned from kdb_task_state_char(), which is not entirely
	 * appropriate for calling from xmon. This could be moved
	 * to a common, generic, routine used by both.
	 */
	state = (p_state == TASK_RUNNING) ? 'R' :
		(p_state & TASK_UNINTERRUPTIBLE) ? 'D' :
		(p_state & TASK_STOPPED) ? 'T' :
		(p_state & TASK_TRACED) ? 'C' :
		(tsk->exit_state & EXIT_ZOMBIE) ? 'Z' :
		(tsk->exit_state & EXIT_DEAD) ? 'E' :
		(p_state & TASK_INTERRUPTIBLE) ? 'S' : '?';

	printf("%16px %16lx %16px %6d %6d %c %2d %s\n", tsk,
		tsk->thread.ksp, tsk->thread.regs,
		tsk->pid, rcu_dereference(tsk->parent)->pid,
		state, task_cpu(tsk),
		tsk->comm);
}

#ifdef CONFIG_PPC_BOOK3S_64
static void format_pte(void *ptep, unsigned long pte)
{
	pte_t entry = __pte(pte);

	printf("ptep @ 0x%016lx = 0x%016lx\n", (unsigned long)ptep, pte);
	printf("Maps physical address = 0x%016lx\n", pte & PTE_RPN_MASK);

	printf("Flags = %s%s%s%s%s\n",
	       pte_young(entry) ? "Accessed " : "",
	       pte_dirty(entry) ? "Dirty " : "",
	       pte_read(entry)  ? "Read " : "",
	       pte_write(entry) ? "Write " : "",
	       pte_exec(entry)  ? "Exec " : "");
}

static void show_pte(unsigned long addr)
{
	unsigned long tskv = 0;
	struct task_struct *volatile tsk = NULL;
	struct mm_struct *volatile mm;
	pgd_t *pgdp;
	p4d_t *p4dp;
	pud_t *pudp;
	pmd_t *pmdp;
	pte_t *ptep;

	if (!scanhex(&tskv))
		mm = &init_mm;
	else
		tsk = (struct task_struct *)tskv;

	if (tsk == NULL)
		mm = &init_mm;
	else
		mm = tsk->active_mm;

	if (setjmp(bus_error_jmp) != 0) {
		catch_memory_errors = 0;
		printf("*** Error dumping pte for task %px\n", tsk);
		return;
	}

	catch_memory_errors = 1;
	sync();

	if (mm == &init_mm)
		pgdp = pgd_offset_k(addr);
	else
		pgdp = pgd_offset(mm, addr);

	p4dp = p4d_offset(pgdp, addr);

	if (p4d_none(*p4dp)) {
		printf("No valid P4D\n");
		return;
	}

	if (p4d_leaf(*p4dp)) {
		format_pte(p4dp, p4d_val(*p4dp));
		return;
	}

	printf("p4dp @ 0x%px = 0x%016lx\n", p4dp, p4d_val(*p4dp));

	pudp = pud_offset(p4dp, addr);

	if (pud_none(*pudp)) {
		printf("No valid PUD\n");
		return;
	}

	if (pud_leaf(*pudp)) {
		format_pte(pudp, pud_val(*pudp));
		return;
	}

	printf("pudp @ 0x%px = 0x%016lx\n", pudp, pud_val(*pudp));

	pmdp = pmd_offset(pudp, addr);

	if (pmd_none(*pmdp)) {
		printf("No valid PMD\n");
		return;
	}

	if (pmd_leaf(*pmdp)) {
		format_pte(pmdp, pmd_val(*pmdp));
		return;
	}
	printf("pmdp @ 0x%px = 0x%016lx\n", pmdp, pmd_val(*pmdp));

	ptep = pte_offset_map(pmdp, addr);
	if (!ptep || pte_none(*ptep)) {
		if (ptep)
			pte_unmap(ptep);
		printf("no valid PTE\n");
		return;
	}

	format_pte(ptep, pte_val(*ptep));
	pte_unmap(ptep);

	sync();
	__delay(200);
	catch_memory_errors = 0;
}
#else
static void show_pte(unsigned long addr)
{
	printf("show_pte not yet implemented\n");
}
#endif /* CONFIG_PPC_BOOK3S_64 */

static void show_tasks(void)
{
	unsigned long tskv;
	struct task_struct *volatile tsk = NULL;

	printf("     task_struct     ->thread.ksp    ->thread.regs    PID   PPID S  P CMD\n");

	if (scanhex(&tskv))
		tsk = (struct task_struct *)tskv;

	if (setjmp(bus_error_jmp) != 0) {
		catch_memory_errors = 0;
		printf("*** Error dumping task %px\n", tsk);
		return;
	}

	catch_memory_errors = 1;
	sync();

	if (tsk)
		show_task(tsk);
	else
		for_each_process(tsk)
			show_task(tsk);

	sync();
	__delay(200);
	catch_memory_errors = 0;
}

static void proccall(void)
{
	unsigned long args[8];
	unsigned long ret;
	int i;
	typedef unsigned long (*callfunc_t)(unsigned long, unsigned long,
			unsigned long, unsigned long, unsigned long,
			unsigned long, unsigned long, unsigned long);
	callfunc_t func;

	if (!scanhex(&adrs))
		return;
	if (termch != '\n')
		termch = 0;
	for (i = 0; i < 8; ++i)
		args[i] = 0;
	for (i = 0; i < 8; ++i) {
		if (!scanhex(&args[i]) || termch == '\n')
			break;
		termch = 0;
	}
	func = (callfunc_t) adrs;
	ret = 0;
	if (setjmp(bus_error_jmp) == 0) {
		catch_memory_errors = 1;
		sync();
		ret = func(args[0], args[1], args[2], args[3],
			   args[4], args[5], args[6], args[7]);
		sync();
		printf("return value is 0x%lx\n", ret);
	} else {
		printf("*** %x exception occurred\n", fault_except);
	}
	catch_memory_errors = 0;
}

/* Input scanning routines */
int
skipbl(void)
{
	int c;

	if( termch != 0 ){
		c = termch;
		termch = 0;
	} else
		c = inchar();
	while( c == ' ' || c == '\t' )
		c = inchar();
	return c;
}

#define N_PTREGS	44
static const char *regnames[N_PTREGS] = {
	"r0", "r1", "r2", "r3", "r4", "r5", "r6", "r7",
	"r8", "r9", "r10", "r11", "r12", "r13", "r14", "r15",
	"r16", "r17", "r18", "r19", "r20", "r21", "r22", "r23",
	"r24", "r25", "r26", "r27", "r28", "r29", "r30", "r31",
	"pc", "msr", "or3", "ctr", "lr", "xer", "ccr",
#ifdef CONFIG_PPC64
	"softe",
#else
	"mq",
#endif
	"trap", "dar", "dsisr", "res"
};

int
scanhex(unsigned long *vp)
{
	int c, d;
	unsigned long v;

	c = skipbl();
	if (c == '%') {
		/* parse register name */
		char regname[8];
		int i;

		for (i = 0; i < sizeof(regname) - 1; ++i) {
			c = inchar();
			if (!isalnum(c)) {
				termch = c;
				break;
			}
			regname[i] = c;
		}
		regname[i] = 0;
		i = match_string(regnames, N_PTREGS, regname);
		if (i < 0) {
			printf("invalid register name '%%%s'\n", regname);
			return 0;
		}
		if (xmon_regs == NULL) {
			printf("regs not available\n");
			return 0;
		}
		*vp = ((unsigned long *)xmon_regs)[i];
		return 1;
	}

	/* skip leading "0x" if any */

	if (c == '0') {
		c = inchar();
		if (c == 'x') {
			c = inchar();
		} else {
			d = hexdigit(c);
			if (d == EOF) {
				termch = c;
				*vp = 0;
				return 1;
			}
		}
	} else if (c == '$') {
		int i;
		for (i = 0; i < (KSYM_NAME_LEN - 1); i++) {
			c = inchar();
			if (isspace(c) || c == '\0') {
				termch = c;
				break;
			}
			tmpstr[i] = c;
		}
		tmpstr[i++] = 0;
		*vp = 0;
		if (setjmp(bus_error_jmp) == 0) {
			catch_memory_errors = 1;
			sync();
			*vp = kallsyms_lookup_name(tmpstr);
			sync();
		}
		catch_memory_errors = 0;
		if (!(*vp)) {
			printf("unknown symbol '%s'\n", tmpstr);
			return 0;
		}
		return 1;
	}

	d = hexdigit(c);
	if (d == EOF) {
		termch = c;
		return 0;
	}
	v = 0;
	do {
		v = (v << 4) + d;
		c = inchar();
		d = hexdigit(c);
	} while (d != EOF);
	termch = c;
	*vp = v;
	return 1;
}

static void
scannl(void)
{
	int c;

	c = termch;
	termch = 0;
	while( c != '\n' )
		c = inchar();
}

static int hexdigit(int c)
{
	if( '0' <= c && c <= '9' )
		return c - '0';
	if( 'A' <= c && c <= 'F' )
		return c - ('A' - 10);
	if( 'a' <= c && c <= 'f' )
		return c - ('a' - 10);
	return EOF;
}

void
getstring(char *s, int size)
{
	int c;

	c = skipbl();
	if (c == '\n') {
		*s = 0;
		return;
	}

	do {
		if( size > 1 ){
			*s++ = c;
			--size;
		}
		c = inchar();
	} while( c != ' ' && c != '\t' && c != '\n' );
	termch = c;
	*s = 0;
}

static char line[256];
static char *lineptr;

static void
flush_input(void)
{
	lineptr = NULL;
}

static int
inchar(void)
{
	if (lineptr == NULL || *lineptr == 0) {
		if (xmon_gets(line, sizeof(line)) == NULL) {
			lineptr = NULL;
			return EOF;
		}
		lineptr = line;
	}
	return *lineptr++;
}

static void
take_input(char *str)
{
	lineptr = str;
}


static void
symbol_lookup(void)
{
	int type = inchar();
	unsigned long addr, cpu;
	void __percpu *ptr = NULL;
	static char tmp[KSYM_NAME_LEN];

	switch (type) {
	case 'a':
		if (scanhex(&addr))
			xmon_print_symbol(addr, ": ", "\n");
		termch = 0;
		break;
	case 's':
		getstring(tmp, KSYM_NAME_LEN);
		if (setjmp(bus_error_jmp) == 0) {
			catch_memory_errors = 1;
			sync();
			addr = kallsyms_lookup_name(tmp);
			if (addr)
				printf("%s: %lx\n", tmp, addr);
			else
				printf("Symbol '%s' not found.\n", tmp);
			sync();
		}
		catch_memory_errors = 0;
		termch = 0;
		break;
	case 'p':
		getstring(tmp, KSYM_NAME_LEN);
		if (setjmp(bus_error_jmp) == 0) {
			catch_memory_errors = 1;
			sync();
			ptr = (void __percpu *)kallsyms_lookup_name(tmp);
			sync();
		}

		if (ptr &&
		    ptr >= (void __percpu *)__per_cpu_start &&
		    ptr < (void __percpu *)__per_cpu_end)
		{
			if (scanhex(&cpu) && cpu < num_possible_cpus()) {
				addr = (unsigned long)per_cpu_ptr(ptr, cpu);
			} else {
				cpu = raw_smp_processor_id();
				addr = (unsigned long)this_cpu_ptr(ptr);
			}

			printf("%s for cpu 0x%lx: %lx\n", tmp, cpu, addr);
		} else {
			printf("Percpu symbol '%s' not found.\n", tmp);
		}

		catch_memory_errors = 0;
		termch = 0;
		break;
	}
}


/* 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 *volatile name = NULL;
	unsigned long offset, size;

	printf(REG, address);
	if (setjmp(bus_error_jmp) == 0) {
		catch_memory_errors = 1;
		sync();
		name = kallsyms_lookup(address, &size, &offset, &modname,
				       tmpstr);
		sync();
		/* wait a little while to see if we get a machine check */
		__delay(200);
	}

	catch_memory_errors = 0;

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

#ifdef CONFIG_PPC_64S_HASH_MMU
void dump_segments(void)
{
	int i;
	unsigned long esid,vsid;
	unsigned long llp;

	printf("SLB contents of cpu 0x%x\n", smp_processor_id());

	for (i = 0; i < mmu_slb_size; i++) {
		asm volatile("slbmfee  %0,%1" : "=r" (esid) : "r" (i));
		asm volatile("slbmfev  %0,%1" : "=r" (vsid) : "r" (i));

		if (!esid && !vsid)
			continue;

		printf("%02d %016lx %016lx", i, esid, vsid);

		if (!(esid & SLB_ESID_V)) {
			printf("\n");
			continue;
		}

		llp = vsid & SLB_VSID_LLP;
		if (vsid & SLB_VSID_B_1T) {
			printf("  1T  ESID=%9lx  VSID=%13lx LLP:%3lx \n",
				GET_ESID_1T(esid),
				(vsid & ~SLB_VSID_B) >> SLB_VSID_SHIFT_1T,
				llp);
		} else {
			printf(" 256M ESID=%9lx  VSID=%13lx LLP:%3lx \n",
				GET_ESID(esid),
				(vsid & ~SLB_VSID_B) >> SLB_VSID_SHIFT,
				llp);
		}
	}
}
#endif

#ifdef CONFIG_PPC_BOOK3S_32
void dump_segments(void)
{
	int i;

	printf("sr0-15 =");
	for (i = 0; i < 16; ++i)
		printf(" %x", mfsr(i << 28));
	printf("\n");
}
#endif

#ifdef CONFIG_44x
static void dump_tlb_44x(void)
{
	int i;

	for (i = 0; i < PPC44x_TLB_SIZE; i++) {
		unsigned long w0,w1,w2;
		asm volatile("tlbre  %0,%1,0" : "=r" (w0) : "r" (i));
		asm volatile("tlbre  %0,%1,1" : "=r" (w1) : "r" (i));
		asm volatile("tlbre  %0,%1,2" : "=r" (w2) : "r" (i));
		printf("[%02x] %08lx %08lx %08lx ", i, w0, w1, w2);
		if (w0 & PPC44x_TLB_VALID) {
			printf("V %08lx -> %01lx%08lx %c%c%c%c%c",
			       w0 & PPC44x_TLB_EPN_MASK,
			       w1 & PPC44x_TLB_ERPN_MASK,
			       w1 & PPC44x_TLB_RPN_MASK,
			       (w2 & PPC44x_TLB_W) ? 'W' : 'w',
			       (w2 & PPC44x_TLB_I) ? 'I' : 'i',
			       (w2 & PPC44x_TLB_M) ? 'M' : 'm',
			       (w2 & PPC44x_TLB_G) ? 'G' : 'g',
			       (w2 & PPC44x_TLB_E) ? 'E' : 'e');
		}
		printf("\n");
	}
}
#endif /* CONFIG_44x */

#ifdef CONFIG_PPC_BOOK3E_64
static void dump_tlb_book3e(void)
{
	u32 mmucfg;
	u64 ramask;
	int i, tlb, ntlbs, pidsz, lpidsz, rasz;
	int mmu_version;
	static const char *pgsz_names[] = {
		"  1K",
		"  2K",
		"  4K",
		"  8K",
		" 16K",
		" 32K",
		" 64K",
		"128K",
		"256K",
		"512K",
		"  1M",
		"  2M",
		"  4M",
		"  8M",
		" 16M",
		" 32M",
		" 64M",
		"128M",
		"256M",
		"512M",
		"  1G",
		"  2G",
		"  4G",
		"  8G",
		" 16G",
		" 32G",
		" 64G",
		"128G",
		"256G",
		"512G",
		"  1T",
		"  2T",
	};

	/* Gather some infos about the MMU */
	mmucfg = mfspr(SPRN_MMUCFG);
	mmu_version = (mmucfg & 3) + 1;
	ntlbs = ((mmucfg >> 2) & 3) + 1;
	pidsz = ((mmucfg >> 6) & 0x1f) + 1;
	lpidsz = (mmucfg >> 24) & 0xf;
	rasz = (mmucfg >> 16) & 0x7f;
	printf("Book3E MMU MAV=%d.0,%d TLBs,%d-bit PID,%d-bit LPID,%d-bit RA\n",
	       mmu_version, ntlbs, pidsz, lpidsz, rasz);
	ramask = (1ull << rasz) - 1;

	for (tlb = 0; tlb < ntlbs; tlb++) {
		u32 tlbcfg;
		int nent, assoc, new_cc = 1;
		printf("TLB %d:\n------\n", tlb);
		switch(tlb) {
		case 0:
			tlbcfg = mfspr(SPRN_TLB0CFG);
			break;
		case 1:
			tlbcfg = mfspr(SPRN_TLB1CFG);
			break;
		case 2:
			tlbcfg = mfspr(SPRN_TLB2CFG);
			break;
		case 3:
			tlbcfg = mfspr(SPRN_TLB3CFG);
			break;
		default:
			printf("Unsupported TLB number !\n");
			continue;
		}
		nent = tlbcfg & 0xfff;
		assoc = (tlbcfg >> 24) & 0xff;
		for (i = 0; i < nent; i++) {
			u32 mas0 = MAS0_TLBSEL(tlb);
			u32 mas1 = MAS1_TSIZE(BOOK3E_PAGESZ_4K);
			u64 mas2 = 0;
			u64 mas7_mas3;
			int esel = i, cc = i;

			if (assoc != 0) {
				cc = i / assoc;
				esel = i % assoc;
				mas2 = cc * 0x1000;
			}

			mas0 |= MAS0_ESEL(esel);
			mtspr(SPRN_MAS0, mas0);
			mtspr(SPRN_MAS1, mas1);
			mtspr(SPRN_MAS2, mas2);
			asm volatile("tlbre  0,0,0" : : : "memory");
			mas1 = mfspr(SPRN_MAS1);
			mas2 = mfspr(SPRN_MAS2);
			mas7_mas3 = mfspr(SPRN_MAS7_MAS3);
			if (assoc && (i % assoc) == 0)
				new_cc = 1;
			if (!(mas1 & MAS1_VALID))
				continue;
			if (assoc == 0)
				printf("%04x- ", i);
			else if (new_cc)
				printf("%04x-%c", cc, 'A' + esel);
			else
				printf("    |%c", 'A' + esel);
			new_cc = 0;
			printf(" %016llx %04x %s %c%c AS%c",
			       mas2 & ~0x3ffull,
			       (mas1 >> 16) & 0x3fff,
			       pgsz_names[(mas1 >> 7) & 0x1f],
			       mas1 & MAS1_IND ? 'I' : ' ',
			       mas1 & MAS1_IPROT ? 'P' : ' ',
			       mas1 & MAS1_TS ? '1' : '0');
			printf(" %c%c%c%c%c%c%c",
			       mas2 & MAS2_X0 ? 'a' : ' ',
			       mas2 & MAS2_X1 ? 'v' : ' ',
			       mas2 & MAS2_W  ? 'w' : ' ',
			       mas2 & MAS2_I  ? 'i' : ' ',
			       mas2 & MAS2_M  ? 'm' : ' ',
			       mas2 & MAS2_G  ? 'g' : ' ',
			       mas2 & MAS2_E  ? 'e' : ' ');
			printf(" %016llx", mas7_mas3 & ramask & ~0x7ffull);
			if (mas1 & MAS1_IND)
				printf(" %s\n",
				       pgsz_names[(mas7_mas3 >> 1) & 0x1f]);
			else
				printf(" U%c%c%c S%c%c%c\n",
				       mas7_mas3 & MAS3_UX ? 'x' : ' ',
				       mas7_mas3 & MAS3_UW ? 'w' : ' ',
				       mas7_mas3 & MAS3_UR ? 'r' : ' ',
				       mas7_mas3 & MAS3_SX ? 'x' : ' ',
				       mas7_mas3 & MAS3_SW ? 'w' : ' ',
				       mas7_mas3 & MAS3_SR ? 'r' : ' ');
		}
	}
}
#endif /* CONFIG_PPC_BOOK3E_64 */

static void xmon_init(int enable)
{
	if (enable) {
		__debugger = xmon;
		__debugger_ipi = xmon_ipi;
		__debugger_bpt = xmon_bpt;
		__debugger_sstep = xmon_sstep;
		__debugger_iabr_match = xmon_iabr_match;
		__debugger_break_match = xmon_break_match;
		__debugger_fault_handler = xmon_fault_handler;
	} else {
		__debugger = NULL;
		__debugger_ipi = NULL;
		__debugger_bpt = NULL;
		__debugger_sstep = NULL;
		__debugger_iabr_match = NULL;
		__debugger_break_match = NULL;
		__debugger_fault_handler = NULL;
	}
}

#ifdef CONFIG_MAGIC_SYSRQ
static void sysrq_handle_xmon(u8 key)
{
	if (xmon_is_locked_down()) {
		clear_all_bpt();
		xmon_init(0);
		return;
	}
	/* ensure xmon is enabled */
	xmon_init(1);
	debugger(get_irq_regs());
	if (!xmon_on)
		xmon_init(0);
}

static const struct sysrq_key_op sysrq_xmon_op = {
	.handler =	sysrq_handle_xmon,
	.help_msg =	"xmon(x)",
	.action_msg =	"Entering xmon",
};

static int __init setup_xmon_sysrq(void)
{
	register_sysrq_key('x', &sysrq_xmon_op);
	return 0;
}
device_initcall(setup_xmon_sysrq);
#endif /* CONFIG_MAGIC_SYSRQ */

static void clear_all_bpt(void)
{
	int i;

	/* clear/unpatch all breakpoints */
	remove_bpts();
	remove_cpu_bpts();

	/* Disable all breakpoints */
	for (i = 0; i < NBPTS; ++i)
		bpts[i].enabled = 0;

	/* Clear any data or iabr breakpoints */
	iabr = NULL;
	for (i = 0; i < nr_wp_slots(); i++)
		dabr[i].enabled = 0;
}

#ifdef CONFIG_DEBUG_FS
static int xmon_dbgfs_set(void *data, u64 val)
{
	xmon_on = !!val;
	xmon_init(xmon_on);

	/* make sure all breakpoints removed when disabling */
	if (!xmon_on) {
		clear_all_bpt();
		get_output_lock();
		printf("xmon: All breakpoints cleared\n");
		release_output_lock();
	}

	return 0;
}

static int xmon_dbgfs_get(void *data, u64 *val)
{
	*val = xmon_on;
	return 0;
}

DEFINE_SIMPLE_ATTRIBUTE(xmon_dbgfs_ops, xmon_dbgfs_get,
			xmon_dbgfs_set, "%llu\n");

static int __init setup_xmon_dbgfs(void)
{
	debugfs_create_file("xmon", 0600, arch_debugfs_dir, NULL,
			    &xmon_dbgfs_ops);
	return 0;
}
device_initcall(setup_xmon_dbgfs);
#endif /* CONFIG_DEBUG_FS */

static int xmon_early __initdata;

static int __init early_parse_xmon(char *p)
{
	if (xmon_is_locked_down()) {
		xmon_init(0);
		xmon_early = 0;
		xmon_on = 0;
	} else if (!p || strncmp(p, "early", 5) == 0) {
		/* just "xmon" is equivalent to "xmon=early" */
		xmon_init(1);
		xmon_early = 1;
		xmon_on = 1;
	} else if (strncmp(p, "on", 2) == 0) {
		xmon_init(1);
		xmon_on = 1;
	} else if (strncmp(p, "rw", 2) == 0) {
		xmon_init(1);
		xmon_on = 1;
		xmon_is_ro = false;
	} else if (strncmp(p, "ro", 2) == 0) {
		xmon_init(1);
		xmon_on = 1;
		xmon_is_ro = true;
	} else if (strncmp(p, "off", 3) == 0)
		xmon_on = 0;
	else
		return 1;

	return 0;
}
early_param("xmon", early_parse_xmon);

void __init xmon_setup(void)
{
	if (xmon_on)
		xmon_init(1);
	if (xmon_early)
		debugger(NULL);
}