powerpc: Merge xmon

The merged version follows the ppc64 version pretty closely mostly,
and in fact ARCH=ppc64 now uses the arch/powerpc/xmon version.
The main difference for ppc64 is that the 'p' command to call
show_state (which was always pretty dodgy) has been replaced by
the ppc32 'p' command, which calls a given procedure (so in fact
the old 'p' command behaviour can be achieved with 'p $show_state').

Signed-off-by: Paul Mackerras <paulus@samba.org>

1 files changed, 2530 insertions, 0 deletions

diff --git a/arch/powerpc/xmon/xmon.c b/arch/powerpc/xmon/xmon.c
new file mode 100644
index 00000000000..d0623e0fd8e
--- /dev/null
+++ b/arch/powerpc/xmon/xmon.c
@@ -0,0 +1,2530 @@
+/*
+ * Routines providing a simple monitor for use on the PowerMac.
+ *
+ * Copyright (C) 1996 Paul Mackerras.
+ *
+ *      This program is free software; you can redistribute it and/or
+ *      modify it under the terms of the GNU General Public License
+ *      as published by the Free Software Foundation; either version
+ *      2 of the License, or (at your option) any later version.
+ */
+#include <linux/config.h>
+#include <linux/errno.h>
+#include <linux/sched.h>
+#include <linux/smp.h>
+#include <linux/mm.h>
+#include <linux/reboot.h>
+#include <linux/delay.h>
+#include <linux/kallsyms.h>
+#include <linux/cpumask.h>
+#include <linux/module.h>
+
+#include <asm/ptrace.h>
+#include <asm/string.h>
+#include <asm/prom.h>
+#include <asm/machdep.h>
+#include <asm/xmon.h>
+#ifdef CONFIG_PMAC_BACKLIGHT
+#include <asm/backlight.h>
+#endif
+#include <asm/processor.h>
+#include <asm/pgtable.h>
+#include <asm/mmu.h>
+#include <asm/mmu_context.h>
+#include <asm/cputable.h>
+#include <asm/rtas.h>
+#include <asm/sstep.h>
+#include <asm/bug.h>
+
+#ifdef CONFIG_PPC64
+#include <asm/hvcall.h>
+#include <asm/paca.h>
+#endif
+
+#include "nonstdio.h"
+
+#define scanhex	xmon_scanhex
+#define skipbl	xmon_skipbl
+
+#ifdef CONFIG_SMP
+cpumask_t cpus_in_xmon = CPU_MASK_NONE;
+static unsigned long xmon_taken = 1;
+static int xmon_owner;
+static int xmon_gate;
+#endif /* CONFIG_SMP */
+
+static unsigned long in_xmon = 0;
+
+static unsigned long adrs;
+static int size = 1;
+#define MAX_DUMP (128 * 1024)
+static unsigned long ndump = 64;
+static unsigned long nidump = 16;
+static unsigned long ncsum = 4096;
+static int termch;
+static char tmpstr[128];
+
+#define JMP_BUF_LEN	23
+static long bus_error_jmp[JMP_BUF_LEN];
+static int catch_memory_errors;
+static long *xmon_fault_jmp[NR_CPUS];
+#define setjmp xmon_setjmp
+#define longjmp xmon_longjmp
+
+/* Breakpoint stuff */
+struct bpt {
+	unsigned long	address;
+	unsigned int	instr[2];
+	atomic_t	ref_count;
+	int		enabled;
+	unsigned long	pad;
+};
+
+/* Bits in bpt.enabled */
+#define BP_IABR_TE	1		/* IABR translation enabled */
+#define BP_IABR		2
+#define BP_TRAP		8
+#define BP_DABR		0x10
+
+#define NBPTS	256
+static struct bpt bpts[NBPTS];
+static struct bpt dabr;
+static struct bpt *iabr;
+static unsigned bpinstr = 0x7fe00008;	/* 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 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 long, long);
+static int ppc_inst_dump(unsigned long, long, int);
+void print_address(unsigned long);
+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 unsigned long read_spr(int);
+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);
+void dump_segments(void);
+static void symbol_lookup(void);
+static void xmon_print_symbol(unsigned long address, const char *mid,
+			      const char *after);
+static const char *getvecname(unsigned long vec);
+
+extern int print_insn_powerpc(unsigned long, unsigned long, int);
+extern void printf(const char *fmt, ...);
+extern void xmon_vfprintf(void *f, const char *fmt, va_list ap);
+extern int xmon_putc(int c, void *f);
+extern int putchar(int ch);
+
+extern void xmon_enter(void);
+extern void xmon_leave(void);
+
+extern int xmon_read_poll(void);
+extern long setjmp(long *);
+extern void longjmp(long *, long);
+extern void xmon_save_regs(struct pt_regs *);
+
+#ifdef CONFIG_PPC64
+#define REG		"%.16lx"
+#define REGS_PER_LINE	4
+#define LAST_VOLATILE	13
+#else
+#define REG		"%.8lx"
+#define REGS_PER_LINE	8
+#define LAST_VOLATILE	12
+#endif
+
+#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\
+  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"
+#endif
+  "\
+  C	checksum\n\
+  d	dump bytes\n\
+  di	dump instructions\n\
+  df	dump float values\n\
+  dd	dump double values\n\
+  e	print exception information\n\
+  f	flush cache\n\
+  la	lookup symbol+offset of specified address\n\
+  ls	lookup address of specified symbol\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\
+  r	print registers\n\
+  s	single step\n\
+  S	print special registers\n\
+  t	print backtrace\n\
+  T	Enable/Disable PPCDBG flags\n\
+  x	exit monitor and recover\n\
+  X	exit monitor and dont recover\n"
+#ifdef CONFIG_PPC64
+"  u	dump segment table or SLB\n"
+#endif
+#ifdef CONFIG_PPC_STD_MMU_32
+"  u	dump segment registers\n"
+#endif
+"  ?	help\n"
+"  zr	reboot\n\
+  zh	halt\n"
+;
+
+static struct pt_regs *xmon_regs;
+
+static inline void sync(void)
+{
+	asm volatile("sync; isync");
+}
+
+static inline void store_inst(void *p)
+{
+	asm volatile ("dcbst 0,%0; sync; icbi 0,%0; isync" : : "r" (p));
+}
+
+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));
+}
+
+/*
+ * 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;
+
+	/*
+	 * 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.
+	 */
+	args.token = rtas_token("set-indicator");
+	if (args.token == RTAS_UNKNOWN_SERVICE)
+		return;
+	args.nargs = 3;
+	args.nret = 1;
+	args.rets = &args.args[3];
+	args.args[0] = SURVEILLANCE_TOKEN;
+	args.args[1] = 0;
+	args.args[2] = 0;
+	enter_rtas(__pa(&args));
+#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 (;;) {
+		if (xmon_speaker == 0) {
+			last_speaker = cmpxchg(&xmon_speaker, 0, me);
+			if (last_speaker == 0)
+				return;
+		}
+		timeout = 10000000;
+		while (xmon_speaker == last_speaker) {
+			if (--timeout > 0)
+				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;
+}
+#endif
+
+int xmon_core(struct pt_regs *regs, int fromipi)
+{
+	int cmd = 0;
+	unsigned long msr;
+	struct bpt *bp;
+	long recurse_jmp[JMP_BUF_LEN];
+	unsigned long offset;
+#ifdef CONFIG_SMP
+	int cpu;
+	int secondary;
+	unsigned long timeout;
+#endif
+
+	msr = mfmsr();
+	mtmsr(msr & ~MSR_EE);	/* disable interrupts */
+
+	bp = in_breakpoint_table(regs->nip, &offset);
+	if (bp != NULL) {
+		regs->nip = bp->address + offset;
+		atomic_dec(&bp->ref_count);
+	}
+
+	remove_cpu_bpts();
+
+#ifdef CONFIG_SMP
+	cpu = smp_processor_id();
+	if (cpu_isset(cpu, cpus_in_xmon)) {
+		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;
+	cpu_set(cpu, cpus_in_xmon);
+
+	bp = NULL;
+	if ((regs->msr & (MSR_IR|MSR_PR|MSR_SF)) == (MSR_IR|MSR_SF))
+		bp = at_breakpoint(regs->nip);
+	if (bp || (regs->msr & MSR_RI) == 0)
+		fromipi = 0;
+
+	if (!fromipi) {
+		get_output_lock();
+		excprint(regs);
+		if (bp) {
+			printf("cpu 0x%x stopped at breakpoint 0x%x (",
+			       cpu, BP_NUM(bp));
+			xmon_print_symbol(regs->nip, " ", ")\n");
+		}
+		if ((regs->msr & MSR_RI) == 0)
+			printf("WARNING: exception is not recoverable, "
+			       "can't continue\n");
+		release_output_lock();
+	}
+
+ waiting:
+	secondary = 1;
+	while (secondary && !xmon_gate) {
+		if (in_xmon == 0) {
+			if (fromipi)
+				goto leave;
+			secondary = test_and_set_bit(0, &in_xmon);
+		}
+		barrier();
+	}
+
+	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) {
+			smp_send_debugger_break(MSG_ALL_BUT_SELF);
+			/* wait for other cpus to come in */
+			for (timeout = 100000000; timeout != 0; --timeout) {
+				if (cpus_weight(cpus_in_xmon) >= ncpus)
+					break;
+				barrier();
+			}
+		}
+		remove_bpts();
+		disable_surveillance();
+		/* for breakpoint or single step, print the current instr. */
+		if (bp || TRAP(regs) == 0xd00)
+			ppc_inst_dump(regs->nip, 1, 0);
+		printf("enter ? for help\n");
+		mb();
+		xmon_gate = 1;
+		barrier();
+	}
+
+ cmdloop:
+	while (in_xmon) {
+		if (secondary) {
+			if (cpu == xmon_owner) {
+				if (!test_and_set_bit(0, &xmon_taken)) {
+					secondary = 0;
+					continue;
+				}
+				/* missed it */
+				while (cpu == xmon_owner)
+					barrier();
+			}
+			barrier();
+		} else {
+			cmd = cmds(regs);
+			if (cmd != 0) {
+				/* exiting xmon */
+				insert_bpts();
+				xmon_gate = 0;
+				wmb();
+				in_xmon = 0;
+				break;
+			}
+			/* have switched to some other cpu */
+			secondary = 1;
+		}
+	}
+ leave:
+	cpu_clear(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 %x (", BP_NUM(bp));
+			xmon_print_symbol(regs->nip, " ", ")\n");
+		}
+		if ((regs->msr & MSR_RI) == 0)
+			printf("WARNING: exception is not recoverable, "
+			       "can't continue\n");
+		remove_bpts();
+		disable_surveillance();
+		/* for breakpoint or single step, print the current instr. */
+		if (bp || TRAP(regs) == 0xd00)
+			ppc_inst_dump(regs->nip, 1, 0);
+		printf("enter ? for help\n");
+	}
+
+	cmd = cmds(regs);
+
+	insert_bpts();
+	in_xmon = 0;
+#endif
+
+	if ((regs->msr & (MSR_IR|MSR_PR|MSR_SF)) == (MSR_IR|MSR_SF)) {
+		bp = at_breakpoint(regs->nip);
+		if (bp != NULL) {
+			int stepped = emulate_step(regs, bp->instr[0]);
+			if (stepped == 0) {
+				regs->nip = (unsigned long) &bp->instr[0];
+				atomic_inc(&bp->ref_count);
+			} else if (stepped < 0) {
+				printf("Couldn't single-step %s instruction\n",
+				    (IS_RFID(bp->instr[0])? "rfid": "mtmsrd"));
+			}
+		}
+	}
+
+	insert_cpu_bpts();
+
+	mtmsr(msr);		/* restore interrupt enable */
+
+	return cmd != 'X';
+}
+
+int xmon(struct pt_regs *excp)
+{
+	struct pt_regs regs;
+
+	if (excp == NULL) {
+		xmon_save_regs(&regs);
+		excp = &regs;
+	}
+	return xmon_core(excp, 0);
+}
+EXPORT_SYMBOL(xmon);
+
+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;
+	unsigned long offset;
+
+	if ((regs->msr & (MSR_IR|MSR_PR|MSR_SF)) != (MSR_IR|MSR_SF))
+		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) {
+		regs->nip = bp->address + 4;
+		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;
+}
+
+int xmon_sstep(struct pt_regs *regs)
+{
+	if (user_mode(regs))
+		return 0;
+	xmon_core(regs, 0);
+	return 1;
+}
+
+int xmon_dabr_match(struct pt_regs *regs)
+{
+	if ((regs->msr & (MSR_IR|MSR_PR|MSR_SF)) != (MSR_IR|MSR_SF))
+		return 0;
+	if (dabr.enabled == 0)
+		return 0;
+	xmon_core(regs, 0);
+	return 1;
+}
+
+int xmon_iabr_match(struct pt_regs *regs)
+{
+	if ((regs->msr & (MSR_IR|MSR_PR|MSR_SF)) != (MSR_IR|MSR_SF))
+		return 0;
+	if (iabr == 0)
+		return 0;
+	xmon_core(regs, 0);
+	return 1;
+}
+
+int xmon_ipi(struct pt_regs *regs)
+{
+#ifdef CONFIG_SMP
+	if (in_xmon && !cpu_isset(smp_processor_id(), cpus_in_xmon))
+		xmon_core(regs, 1);
+#endif
+	return 0;
+}
+
+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_SF)) == (MSR_IR|MSR_SF)) {
+		bp = in_breakpoint_table(regs->nip, &offset);
+		if (bp != NULL) {
+			regs->nip = bp->address + offset;
+			atomic_dec(&bp->ref_count);
+		}
+	}
+
+	return 0;
+}
+
+static struct bpt *at_breakpoint(unsigned long pc)
+{
+	int i;
+	struct bpt *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) bpts;
+	if (off >= sizeof(bpts))
+		return NULL;
+	off %= sizeof(struct bpt);
+	if (off != offsetof(struct bpt, instr[0])
+	    && off != offsetof(struct bpt, instr[1]))
+		return NULL;
+	*offp = off - offsetof(struct bpt, instr[0]);
+	return (struct bpt *) (nip - off);
+}
+
+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[1] = bpinstr;
+			store_inst(&bp->instr[1]);
+			return bp;
+		}
+	}
+
+	printf("Sorry, no free breakpoints.  Please clear one first.\n");
+	return NULL;
+}
+
+static void insert_bpts(void)
+{
+	int i;
+	struct bpt *bp;
+
+	bp = bpts;
+	for (i = 0; i < NBPTS; ++i, ++bp) {
+		if ((bp->enabled & (BP_TRAP|BP_IABR)) == 0)
+			continue;
+		if (mread(bp->address, &bp->instr[0], 4) != 4) {
+			printf("Couldn't read instruction at %lx, "
+			       "disabling breakpoint there\n", bp->address);
+			bp->enabled = 0;
+			continue;
+		}
+		if (IS_MTMSRD(bp->instr[0]) || IS_RFID(bp->instr[0])) {
+			printf("Breakpoint at %lx is on an mtmsrd or rfid "
+			       "instruction, disabling it\n", bp->address);
+			bp->enabled = 0;
+			continue;
+		}
+		store_inst(&bp->instr[0]);
+		if (bp->enabled & BP_IABR)
+			continue;
+		if (mwrite(bp->address, &bpinstr, 4) != 4) {
+			printf("Couldn't write instruction at %lx, "
+			       "disabling breakpoint there\n", bp->address);
+			bp->enabled &= ~BP_TRAP;
+			continue;
+		}
+		store_inst((void *)bp->address);
+	}
+}
+
+static void insert_cpu_bpts(void)
+{
+	if (dabr.enabled)
+		set_dabr(dabr.address | (dabr.enabled & 7));
+	if (iabr && cpu_has_feature(CPU_FTR_IABR))
+		mtspr(SPRN_IABR, iabr->address
+			 | (iabr->enabled & (BP_IABR|BP_IABR_TE)));
+}
+
+static void remove_bpts(void)
+{
+	int i;
+	struct bpt *bp;
+	unsigned instr;
+
+	bp = bpts;
+	for (i = 0; i < NBPTS; ++i, ++bp) {
+		if ((bp->enabled & (BP_TRAP|BP_IABR)) != BP_TRAP)
+			continue;
+		if (mread(bp->address, &instr, 4) == 4
+		    && instr == bpinstr
+		    && mwrite(bp->address, &bp->instr, 4) != 4)
+			printf("Couldn't remove breakpoint at %lx\n",
+			       bp->address);
+		else
+			store_inst((void *)bp->address);
+	}
+}
+
+static void remove_cpu_bpts(void)
+{
+	set_dabr(0);
+	if (cpu_has_feature(CPU_FTR_IABR))
+		mtspr(SPRN_IABR, 0);
+}
+
+/* Command interpreting routine */
+static char *last_cmd;
+
+static int
+cmds(struct pt_regs *excp)
+{
+	int cmd = 0;
+
+	last_cmd = NULL;
+	xmon_regs = excp;
+	for(;;) {
+#ifdef CONFIG_SMP
+		printf("%x:", 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;
+			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':
+		case EOF:
+			return cmd;
+		case '?':
+			printf(help_string);
+			break;
+		case 'b':
+			bpt_cmds();
+			break;
+		case 'C':
+			csum();
+			break;
+		case 'c':
+			if (cpu_cmd())
+				return 0;
+			break;
+		case 'z':
+			bootcmds();
+			break;
+		case 'p':
+			proccall();
+			break;
+#ifdef CONFIG_PPC_STD_MMU
+		case 'u':
+			dump_segments();
+			break;
+#endif
+		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;
+		}
+	}
+}
+
+/*
+ * Step a single instruction.
+ * Some instructions we emulate, others we execute with MSR_SE set.
+ */
+static int do_step(struct pt_regs *regs)
+{
+	unsigned int instr;
+	int stepped;
+
+	/* check we are in 64-bit kernel mode, translation enabled */
+	if ((regs->msr & (MSR_SF|MSR_PR|MSR_IR)) == (MSR_SF|MSR_IR)) {
+		if (mread(regs->nip, &instr, 4) == 4) {
+			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) {
+				regs->trap = 0xd00 | (regs->trap & 1);
+				printf("stepped to ");
+				xmon_print_symbol(regs->nip, " ", "\n");
+				ppc_inst_dump(regs->nip, 1, 0);
+				return 0;
+			}
+		}
+	}
+	regs->msr |= MSR_SE;
+	return 1;
+}
+
+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();
+}
+
+static int cpu_cmd(void)
+{
+#ifdef CONFIG_SMP
+	unsigned long cpu;
+	int timeout;
+	int count;
+
+	if (!scanhex(&cpu)) {
+		/* print cpus waiting or in xmon */
+		printf("cpus stopped:");
+		count = 0;
+		for (cpu = 0; cpu < NR_CPUS; ++cpu) {
+			if (cpu_isset(cpu, cpus_in_xmon)) {
+				if (count == 0)
+					printf(" %x", cpu);
+				++count;
+			} else {
+				if (count > 1)
+					printf("-%x", cpu - 1);
+				count = 0;
+			}
+		}
+		if (count > 1)
+			printf("-%x", NR_CPUS - 1);
+		printf("\n");
+		return 0;
+	}
+	/* try to switch to cpu specified */
+	if (!cpu_isset(cpu, cpus_in_xmon)) {
+		printf("cpu 0x%x isn't in xmon\n", cpu);
+		return 0;
+	}
+	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 %u didn't take control\n", cpu);
+			return 0;
+		}
+		barrier();
+	}
+	return 1;
+#else
+	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 %x\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)
+{
+	unsigned int instr;
+
+	addr &= ~3;
+	if (addr < KERNELBASE) {
+		printf("Breakpoints may only be placed at kernel addresses\n");
+		return 0;
+	}
+	if (!mread(addr, &instr, sizeof(instr))) {
+		printf("Can't read instruction at address %lx\n", addr);
+		return 0;
+	}
+	if (IS_MTMSRD(instr) || IS_RFID(instr)) {
+		printf("Breakpoints may not be placed on mtmsrd or rfid "
+		       "instructions\n");
+		return 0;
+	}
+	return 1;
+}
+
+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 (POWER3/RS64 only)\n"
+    "bd <addr> [cnt]  set hardware data breakpoint\n"
+    "";
+
+static void
+bpt_cmds(void)
+{
+	int cmd;
+	unsigned long a;
+	int mode, i;
+	struct bpt *bp;
+	const char badaddr[] = "Only kernel addresses are permitted "
+		"for breakpoints\n";
+
+	cmd = inchar();
+	switch (cmd) {
+#ifndef CONFIG_8xx
+	case 'd':	/* bd - hardware data breakpoint */
+		mode = 7;
+		cmd = inchar();
+		if (cmd == 'r')
+			mode = 5;
+		else if (cmd == 'w')
+			mode = 6;
+		else
+			termch = cmd;
+		dabr.address = 0;
+		dabr.enabled = 0;
+		if (scanhex(&dabr.address)) {
+			if (dabr.address < KERNELBASE) {
+				printf(badaddr);
+				break;
+			}
+			dabr.address &= ~7;
+			dabr.enabled = mode | BP_DABR;
+		}
+		break;
+
+	case 'i':	/* bi - hardware instr breakpoint */
+		if (!cpu_has_feature(CPU_FTR_IABR)) {
+			printf("Hardware instruction breakpoint "
+			       "not supported on this cpu\n");
+			break;
+		}
+		if (iabr) {
+			iabr->enabled &= ~(BP_IABR | BP_IABR_TE);
+			iabr = NULL;
+		}
+		if (!scanhex(&a))
+			break;
+		if (!check_bp_loc(a))
+			break;
+		bp = new_breakpoint(a);
+		if (bp != NULL) {
+			bp->enabled |= BP_IABR | BP_IABR_TE;
+			iabr = bp;
+		}
+		break;
+#endif
+
+	case 'c':
+		if (!scanhex(&a)) {
+			/* clear all breakpoints */
+			for (i = 0; i < NBPTS; ++i)
+				bpts[i].enabled = 0;
+			iabr = NULL;
+			dabr.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 == 0) {
+				printf("No breakpoint at %x\n", a);
+				break;
+			}
+		}
+
+		printf("Cleared breakpoint %x (", 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 (!scanhex(&a)) {
+			/* print all breakpoints */
+			printf("   type            address\n");
+			if (dabr.enabled) {
+				printf("   data   "REG"  [", dabr.address);
+				if (dabr.enabled & 1)
+					printf("r");
+				if (dabr.enabled & 2)
+					printf("w");
+				printf("]\n");
+			}
+			for (bp = bpts; bp < &bpts[NBPTS]; ++bp) {
+				if (!bp->enabled)
+					continue;
+				printf("%2x %s   ", BP_NUM(bp),
+				    (bp->enabled & BP_IABR)? "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;
+		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:	ret = "(Data SLB Access)"; break;
+	case 0x400:	ret = "(Instruction Access)"; break;
+	case 0x480:	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 0xc00:	ret = "(System Call)"; break;
+	case 0xd00:	ret = "(Single Step)"; break;
+	case 0xf00:	ret = "(Performance Monitor)"; break;
+	case 0xf20:	ret = "(Altivec Unavailable)"; break;
+	case 0x1300:	ret = "(Instruction Breakpoint)"; 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;
+	char *modname;
+
+	*startp = *endp = 0;
+	if (pc == 0)
+		return;
+	if (setjmp(bus_error_jmp) == 0) {
+		catch_memory_errors = 1;
+		sync();
+		name = kallsyms_lookup(pc, &size, &offset, &modname, tmpstr);
+		if (name != NULL) {
+			*startp = pc - offset;
+			*endp = pc - offset + size;
+		}
+		sync();
+	}
+	catch_memory_errors = 0;
+}
+
+static int xmon_depth_to_print = 64;
+
+#ifdef CONFIG_PPC64
+#define LRSAVE_OFFSET		0x10
+#define REG_FRAME_MARKER	0x7265677368657265ul	/* "regshere" */
+#define MARKER_OFFSET		0x60
+#define REGS_OFFSET		0x70
+#else
+#define LRSAVE_OFFSET		4
+#define REG_FRAME_MARKER	0x72656773
+#define MARKER_OFFSET		8
+#define REGS_OFFSET		16
+#endif
+
+static void xmon_show_stack(unsigned long sp, unsigned long lr,
+			    unsigned long pc)
+{
+	unsigned long ip;
+	unsigned long newsp;
+	unsigned long marker;
+	int count = 0;
+	struct pt_regs regs;
+
+	do {
+		if (sp < PAGE_OFFSET) {
+			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 (lr < PAGE_OFFSET
+				    || (fnstart <= lr && lr < fnend))
+					printip = 0;
+			} else if (lr == nextip) {
+				printip = 0;
+			} else if (lr >= PAGE_OFFSET
+				   && !(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 "regshere" marker to see if this is
+		   an exception frame. */
+		if (mread(sp + MARKER_OFFSET, &marker, sizeof(unsigned long))
+		    && marker == REG_FRAME_MARKER) {
+			if (mread(sp + REGS_OFFSET, &regs, sizeof(regs))
+			    != sizeof(regs)) {
+				printf("Couldn't read registers at %lx\n",
+				       sp + REGS_OFFSET);
+				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;
+	} while (count++ < xmon_depth_to_print);
+}
+
+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)
+{
+	struct bug_entry *bug;
+	unsigned long addr;
+
+	if (regs->msr & MSR_PR)
+		return;		/* not in kernel */
+	addr = regs->nip;	/* address of trap instruction */
+	if (addr < PAGE_OFFSET)
+		return;
+	bug = find_bug(regs->nip);
+	if (bug == NULL)
+		return;
+	if (bug->line & BUG_WARNING_TRAP)
+		return;
+
+	printf("kernel BUG in %s at %s:%d!\n",
+	       bug->function, bug->file, (unsigned int)bug->line);
+}
+
+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 [%lx]\n", fp->trap, getvecname(trap), fp);
+	printf("    pc: ");
+	xmon_print_symbol(fp->nip, ": ", "\n");
+
+	printf("    lr: ", fp->link);
+	xmon_print_symbol(fp->link, ": ", "\n");
+
+	printf("    sp: %lx\n", fp->gpr[1]);
+	printf("   msr: %lx\n", fp->msr);
+
+	if (trap == 0x300 || trap == 0x380 || trap == 0x600) {
+		printf("   dar: %lx\n", fp->dar);
+		if (trap != 0x380)
+			printf(" dsisr: %lx\n", fp->dsisr);
+	}
+
+	printf("  current = 0x%lx\n", current);
+#ifdef CONFIG_PPC64
+	printf("  paca    = 0x%lx\n", get_paca());
+#endif
+	if (current) {
+		printf("    pid   = %ld, comm = %s\n",
+		       current->pid, current->comm);
+	}
+
+	if (trap == 0x700)
+		print_bug_trap(fp);
+}
+
+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
+	if (FULL_REGS(fp)) {
+		for (n = 0; n < 16; ++n)
+			printf("R%.2ld = "REG"   R%.2ld = "REG"\n",
+			       n, fp->gpr[n], n+16, fp->gpr[n+16]);
+	} else {
+		for (n = 0; n < 7; ++n)
+			printf("R%.2ld = "REG"   R%.2ld = "REG"\n",
+			       n, fp->gpr[n], n+7, fp->gpr[n+7]);
+	}
+#else
+	for (n = 0; n < 32; ++n) {
+		printf("R%.2d = %.8x%s", n, fp->gpr[n],
+		       (n & 3) == 3? "\n": "   ");
+		if (n == 12 && !FULL_REGS(fp)) {
+			printf("\n");
+			break;
+		}
+	}
+#endif
+	printf("pc  = ");
+	xmon_print_symbol(fp->nip, " ", "\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 == 0x300 || trap == 0x380 || trap == 0x600)
+		printf("dar = "REG"   dsisr = %.8lx\n", fp->dar, fp->dsisr);
+}
+
+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') {
+			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;
+}
+
+unsigned long
+read_spr(int n)
+{
+	unsigned int instrs[2];
+	unsigned long (*code)(void);
+	unsigned long opd[3];
+	unsigned long ret = -1UL;
+
+	instrs[0] = 0x7c6002a6 + ((n & 0x1F) << 16) + ((n & 0x3e0) << 6);
+	instrs[1] = 0x4e800020;
+	opd[0] = (unsigned long)instrs;
+	opd[1] = 0;
+	opd[2] = 0;
+	store_inst(instrs);
+	store_inst(instrs+1);
+	code = (unsigned long (*)(void)) opd;
+
+	if (setjmp(bus_error_jmp) == 0) {
+		catch_memory_errors = 1;
+		sync();
+
+		ret = code();
+
+		sync();
+		/* wait a little while to see if we get a machine check */
+		__delay(200);
+		n = size;
+	}
+
+	return ret;
+}
+
+void
+write_spr(int n, unsigned long val)
+{
+	unsigned int instrs[2];
+	unsigned long (*code)(unsigned long);
+	unsigned long opd[3];
+
+	instrs[0] = 0x7c6003a6 + ((n & 0x1F) << 16) + ((n & 0x3e0) << 6);
+	instrs[1] = 0x4e800020;
+	opd[0] = (unsigned long)instrs;
+	opd[1] = 0;
+	opd[2] = 0;
+	store_inst(instrs);
+	store_inst(instrs+1);
+	code = (unsigned long (*)(unsigned long)) opd;
+
+	if (setjmp(bus_error_jmp) == 0) {
+		catch_memory_errors = 1;
+		sync();
+
+		code(val);
+
+		sync();
+		/* wait a little while to see if we get a machine check */
+		__delay(200);
+		n = size;
+	}
+}
+
+static unsigned long regno;
+extern char exc_prolog;
+extern char dec_exc;
+
+void super_regs(void)
+{
+	int cmd;
+	unsigned long val;
+#ifdef CONFIG_PPC_ISERIES
+	struct paca_struct *ptrPaca = NULL;
+	struct lppaca *ptrLpPaca = NULL;
+	struct ItLpRegSave *ptrLpRegSave = NULL;
+#endif
+
+	cmd = skipbl();
+	if (cmd == '\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));
+#ifdef CONFIG_PPC_ISERIES
+		// Dump out relevant Paca data areas.
+		printf("Paca: \n");
+		ptrPaca = get_paca();
+    
+		printf("  Local Processor Control Area (LpPaca): \n");
+		ptrLpPaca = ptrPaca->lppaca_ptr;
+		printf("    Saved Srr0=%.16lx  Saved Srr1=%.16lx \n",
+		       ptrLpPaca->saved_srr0, ptrLpPaca->saved_srr1);
+		printf("    Saved Gpr3=%.16lx  Saved Gpr4=%.16lx \n",
+		       ptrLpPaca->saved_gpr3, ptrLpPaca->saved_gpr4);
+		printf("    Saved Gpr5=%.16lx \n", ptrLpPaca->saved_gpr5);
+    
+		printf("  Local Processor Register Save Area (LpRegSave): \n");
+		ptrLpRegSave = ptrPaca->reg_save_ptr;
+		printf("    Saved Sprg0=%.16lx  Saved Sprg1=%.16lx \n",
+		       ptrLpRegSave->xSPRG0, ptrLpRegSave->xSPRG0);
+		printf("    Saved Sprg2=%.16lx  Saved Sprg3=%.16lx \n",
+		       ptrLpRegSave->xSPRG2, ptrLpRegSave->xSPRG3);
+		printf("    Saved Msr  =%.16lx  Saved Nia  =%.16lx \n",
+		       ptrLpRegSave->xMSR, ptrLpRegSave->xNIA);
+#endif
+
+		return;
+	}
+
+	scanhex(&regno);
+	switch (cmd) {
+	case 'w':
+		val = read_spr(regno);
+		scanhex(&val);
+		write_spr(regno, val);
+		/* fall through */
+	case 'r':
+		printf("spr %lx = %lx\n", regno, read_spr(regno));
+		break;
+	}
+	scannl();
+}
+
+/*
+ * Stuff for reading and writing memory safely
+ */
+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;
+}
+
+int
+mwrite(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 *)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 %x\n", adrs + n);
+	}
+	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))
+
+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"
+    "";
+
+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("%.16x%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;
+				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;
+	}
+}
+
+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;
+}
+
+#define isxdigit(c)	(('0' <= (c) && (c) <= '9') \
+			 || ('a' <= (c) && (c) <= 'f') \
+			 || ('A' <= (c) && (c) <= 'F'))
+void
+dump(void)
+{
+	int c;
+
+	c = inchar();
+	if ((isxdigit(c) && c != 'f' && c != 'd') || 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_DUMP)
+			nidump = MAX_DUMP;
+		adrs += ppc_inst_dump(adrs, nidump, 1);
+		last_cmd = "di\n";
+	} else {
+		scanhex(&ndump);
+		if (ndump == 0)
+			ndump = 64;
+		else if (ndump > MAX_DUMP)
+			ndump = MAX_DUMP;
+		prdump(adrs, ndump);
+		adrs += ndump;
+		last_cmd = "d\n";
+	}
+}
+
+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 & 7) == 0 && m > 0)
+			    putchar(' ');
+			if (m < nr)
+				printf("%.2x", temp[m]);
+			else
+				printf("%s", fault_chars[fault_type]);
+		}
+		if (m <= 8)
+			printf(" ");
+		for (; m < 16; ++m)
+			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;
+	}
+}
+
+int
+ppc_inst_dump(unsigned long adr, long count, int praddr)
+{
+	int nr, dotted;
+	unsigned long first_adr;
+	unsigned long inst, last_inst = 0;
+	unsigned char val[4];
+
+	dotted = 0;
+	for (first_adr = adr; count > 0; --count, adr += 4) {
+		nr = mread(adr, val, 4);
+		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;
+		}
+		inst = GETWORD(val);
+		if (adr > first_adr && inst == last_inst) {
+			if (!dotted) {
+				printf(" ...\n");
+				dotted = 1;
+			}
+			continue;
+		}
+		dotted = 0;
+		last_inst = inst;
+		if (praddr)
+			printf(REG"  %.8x", adr, inst);
+		printf("\t");
+		print_insn_powerpc(inst, adr, 0);	/* always returns 4 */
+		printf("\n");
+	}
+	return adr - first_adr;
+}
+
+void
+print_address(unsigned long addr)
+{
+	xmon_print_symbol(addr, "\t# ", "");
+}
+
+
+/*
+ * 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 */
+
+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':
+		memmove((void *)mdest, (void *)msrc, mcount);
+		break;
+	case 's':
+		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;
+	}
+}
+
+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("%.16x %.2x # %.16x %.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;
+
+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;
+
+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);
+			fflush(stdout);
+		} else if (!ok && ook)
+			printf("%.8x\n", a - mskip);
+		ook = ok;
+		if (a + mskip < a)
+			break;
+	}
+	if (ook)
+		printf("%.8x\n", a - mskip);
+}
+
+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 %x\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 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;
+		for (i = 0; i < N_PTREGS; ++i) {
+			if (strcmp(regnames[i], regname) == 0) {
+				if (xmon_regs == NULL) {
+					printf("regs not available\n");
+					return 0;
+				}
+				*vp = ((unsigned long *)xmon_regs)[i];
+				return 1;
+			}
+		}
+		printf("invalid register name '%%%s'\n", regname);
+		return 0;
+	}
+
+	/* 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<63; i++) {
+			c = inchar();
+			if (isspace(c)) {
+				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;
+}
+
+void
+scannl(void)
+{
+	int c;
+
+	c = termch;
+	termch = 0;
+	while( c != '\n' )
+		c = inchar();
+}
+
+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();
+	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;
+
+void
+flush_input(void)
+{
+	lineptr = NULL;
+}
+
+int
+inchar(void)
+{
+	if (lineptr == NULL || *lineptr == 0) {
+		if (fgets(line, sizeof(line), stdin) == NULL) {
+			lineptr = NULL;
+			return EOF;
+		}
+		lineptr = line;
+	}
+	return *lineptr++;
+}
+
+void
+take_input(char *str)
+{
+	lineptr = str;
+}
+
+
+static void
+symbol_lookup(void)
+{
+	int type = inchar();
+	unsigned long addr;
+	static char tmp[64];
+
+	switch (type) {
+	case 'a':
+		if (scanhex(&addr))
+			xmon_print_symbol(addr, ": ", "\n");
+		termch = 0;
+		break;
+	case 's':
+		getstring(tmp, 64);
+		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;
+	}
+}
+
+
+/* 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;
+
+	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_PPC64
+static void dump_slb(void)
+{
+	int i;
+	unsigned long tmp;
+
+	printf("SLB contents of cpu %x\n", smp_processor_id());
+
+	for (i = 0; i < SLB_NUM_ENTRIES; i++) {
+		asm volatile("slbmfee  %0,%1" : "=r" (tmp) : "r" (i));
+		printf("%02d %016lx ", i, tmp);
+
+		asm volatile("slbmfev  %0,%1" : "=r" (tmp) : "r" (i));
+		printf("%016lx\n", tmp);
+	}
+}
+
+static void dump_stab(void)
+{
+	int i;
+	unsigned long *tmp = (unsigned long *)get_paca()->stab_addr;
+
+	printf("Segment table contents of cpu %x\n", smp_processor_id());
+
+	for (i = 0; i < PAGE_SIZE/16; i++) {
+		unsigned long a, b;
+
+		a = *tmp++;
+		b = *tmp++;
+
+		if (a || b) {
+			printf("%03d %016lx ", i, a);
+			printf("%016lx\n", b);
+		}
+	}
+}
+
+void dump_segments(void)
+{
+	if (cpu_has_feature(CPU_FTR_SLB))
+		dump_slb();
+	else
+		dump_stab();
+}
+#endif
+
+#ifdef CONFIG_PPC_STD_MMU_32
+void dump_segments(void)
+{
+	int i;
+
+	printf("sr0-15 =");
+	for (i = 0; i < 16; ++i)
+		printf(" %x", mfsrin(i));
+	printf("\n");
+}
+#endif
+
+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_dabr_match = xmon_dabr_match;
+		__debugger_fault_handler = xmon_fault_handler;
+	} else {
+		__debugger = NULL;
+		__debugger_ipi = NULL;
+		__debugger_bpt = NULL;
+		__debugger_sstep = NULL;
+		__debugger_iabr_match = NULL;
+		__debugger_dabr_match = NULL;
+		__debugger_fault_handler = NULL;
+	}
+}