[PATCH] cleanup debugger hooks

Theres still more to do here, but at least the ifdef mess is gone. No
more checking for NULL before calling functions, that was playing with
fire. Oh yeah and lots more deletions :)

Clean up the debugger hooks, it was way too easy to screw up.
And we did. And Linus hit it.

- create CONFIG_DEBUGGER so we can enable kernel debugging options but not
  have any trace of debugger gunk.
- remove a bunch of xmon prototypes so no one gets the urge to call them
- Use die() instead of panic in a number of places, it gives us much better
  debug information.
- Get rid of the ifdef madness

arch/ppc64/Kconfig

@@ -356,9 +356,16 @@ config MAGIC_SYSRQ
 	  keys are documented in <file:Documentation/sysrq.txt>. Don't say Y
 	  unless you really know what this hack does.
 
+config DEBUGGER
+	bool "Enable debugger hooks"
+	depends on DEBUG_KERNEL
+	help
+	  Include in-kernel hooks for kernel debuggers. Unless you are
+	  intending to debug the kernel, say N here.
+
 config XMON
 	bool "Include xmon kernel debugger"
-	depends on DEBUG_KERNEL
+	depends on DEBUGGER
 	help
 	  Include in-kernel hooks for the xmon kernel monitor/debugger.
 	  Unless you are intending to debug the kernel, say N here.

arch/ppc64/kernel/open_pic.c

@@ -645,9 +645,9 @@ void openpic_request_IPIs(void)
 	request_irq(openpic_vec_ipi+1, openpic_ipi_action, SA_INTERRUPT,
 		   "IPI1 (reschedule)", 0);
 	request_irq(openpic_vec_ipi+2, openpic_ipi_action, SA_INTERRUPT,
-		   "IPI2 (invalidate tlb)", 0);
+		   "IPI2 (unused)", 0);
 	request_irq(openpic_vec_ipi+3, openpic_ipi_action, SA_INTERRUPT,
-		   "IPI3 (xmon break)", 0);
+		   "IPI3 (debugger break)", 0);
 
 	for ( i = 0; i < OPENPIC_NUM_IPI ; i++ )
 		openpic_enable_ipi(openpic_vec_ipi+i);

arch/ppc64/kernel/ppc_ksyms.c

@@ -206,25 +206,6 @@ EXPORT_SYMBOL(timer_interrupt);
 EXPORT_SYMBOL(irq_desc);
 EXPORT_SYMBOL(get_wchan);
 EXPORT_SYMBOL(console_drivers);
-#ifdef CONFIG_XMON
-EXPORT_SYMBOL(xmon);
-#endif
-
-#ifdef CONFIG_DEBUG_KERNEL
-extern void (*debugger)(struct pt_regs *regs);
-extern int (*debugger_bpt)(struct pt_regs *regs);
-extern int (*debugger_sstep)(struct pt_regs *regs);
-extern int (*debugger_iabr_match)(struct pt_regs *regs);
-extern int (*debugger_dabr_match)(struct pt_regs *regs);
-extern void (*debugger_fault_handler)(struct pt_regs *regs);
-
-EXPORT_SYMBOL(debugger);
-EXPORT_SYMBOL(debugger_bpt);
-EXPORT_SYMBOL(debugger_sstep);
-EXPORT_SYMBOL(debugger_iabr_match);
-EXPORT_SYMBOL(debugger_dabr_match);
-EXPORT_SYMBOL(debugger_fault_handler);
-#endif
 
 EXPORT_SYMBOL(tb_ticks_per_usec);
 EXPORT_SYMBOL(paca);

arch/ppc64/kernel/setup.c

@@ -42,6 +42,7 @@
 #include <asm/sections.h>
 #include <asm/btext.h>
 #include <asm/nvram.h>
+#include <asm/system.h>
 
 extern unsigned long klimit;
 /* extern void *stab; */
@@ -79,10 +80,6 @@ unsigned long decr_overclock_proc0_set = 0;
 
 int powersave_nap;
 
-#ifdef CONFIG_XMON
-extern void xmon_map_scc(void);
-#endif
-
 char saved_command_line[256];
 unsigned char aux_device_present;
 
@@ -159,15 +156,11 @@ void setup_system(unsigned long r3, unsigned long r4, unsigned long r5,
 		  unsigned long r6, unsigned long r7)
 {
 #ifdef CONFIG_PPC_PSERIES
-        unsigned int ret, i;
+	unsigned int ret, i;
 #endif
 
 #ifdef CONFIG_XMON_DEFAULT
-	debugger = xmon;
-	debugger_bpt = xmon_bpt;
-	debugger_sstep = xmon_sstep;
-	debugger_iabr_match = xmon_iabr_match;
-	debugger_dabr_match = xmon_dabr_match;
+	xmon_init();
 #endif
 
 #ifdef CONFIG_PPC_ISERIES
@@ -601,13 +594,15 @@ void __init setup_arch(char **cmdline_p)
 	calibrate_delay = ppc64_calibrate_delay;
 
 	ppc64_boot_msg(0x12, "Setup Arch");
+
 #ifdef CONFIG_XMON
-	xmon_map_scc();
-	if (strstr(cmd_line, "xmon"))
-		xmon(0);
+	if (strstr(cmd_line, "xmon")) {
+		/* ensure xmon is enabled */
+		xmon_init();
+		debugger(0);
+	}
 #endif /* CONFIG_XMON */
 
-
 	/*
 	 * Set cache line size based on type of cpu as a default.
 	 * Systems with OF can look in the properties on the cpu node(s)

arch/ppc64/kernel/smp.c

@@ -49,6 +49,7 @@
 #include <asm/machdep.h>
 #include <asm/xics.h>
 #include <asm/cputable.h>
+#include <asm/system.h>
 
 int smp_threads_ready;
 unsigned long cache_decay_ticks;
@@ -394,7 +395,7 @@ void smp_local_timer_interrupt(struct pt_regs * regs)
 
 void smp_message_recv(int msg, struct pt_regs *regs)
 {
-	switch( msg ) {
+	switch(msg) {
 	case PPC_MSG_CALL_FUNCTION:
 		smp_call_function_interrupt();
 		break;
@@ -407,11 +408,11 @@ void smp_message_recv(int msg, struct pt_regs *regs)
 		/* spare */
 		break;
 #endif
-#ifdef CONFIG_XMON
-	case PPC_MSG_XMON_BREAK:
-		xmon(regs);
+#ifdef CONFIG_DEBUGGER
+	case PPC_MSG_DEBUGGER_BREAK:
+		debugger(regs);
 		break;
-#endif /* CONFIG_XMON */
+#endif
 	default:
 		printk("SMP %d: smp_message_recv(): unknown msg %d\n",
 		       smp_processor_id(), msg);
@@ -424,12 +425,12 @@ void smp_send_reschedule(int cpu)
 	smp_message_pass(cpu, PPC_MSG_RESCHEDULE, 0, 0);
 }
 
-#ifdef CONFIG_XMON
-void smp_send_xmon_break(int cpu)
+#ifdef CONFIG_DEBUGGER
+void smp_send_debugger_break(int cpu)
 {
-	smp_message_pass(cpu, PPC_MSG_XMON_BREAK, 0, 0);
+	smp_message_pass(cpu, PPC_MSG_DEBUGGER_BREAK, 0, 0);
 }
-#endif /* CONFIG_XMON */
+#endif
 
 static void stop_this_cpu(void *dummy)
 {
@@ -507,10 +508,7 @@ int smp_call_function (void (*func) (void *info), void *info, int nonatomic,
 			printk("smp_call_function on cpu %d: other cpus not "
 			       "responding (%d)\n", smp_processor_id(),
 			       atomic_read(&data.started));
-#ifdef CONFIG_DEBUG_KERNEL
-			if (debugger)
-				debugger(0);
-#endif
+			debugger(0);
 			goto out;
 		}
 	}
@@ -525,10 +523,7 @@ int smp_call_function (void (*func) (void *info), void *info, int nonatomic,
 				       smp_processor_id(),
 				       atomic_read(&data.finished),
 				       atomic_read(&data.started));
-#ifdef CONFIG_DEBUG_KERNEL
-				if (debugger)
-					debugger(0);
-#endif
+				debugger(0);
 				goto out;
 			}
 		}

arch/ppc64/kernel/traps.c

@@ -45,13 +45,20 @@ extern void bad_page_fault(struct pt_regs *, unsigned long, int);
 extern int fwnmi_active;
 #endif
 
-#ifdef CONFIG_DEBUG_KERNEL
-void (*debugger)(struct pt_regs *regs);
-int (*debugger_bpt)(struct pt_regs *regs);
-int (*debugger_sstep)(struct pt_regs *regs);
-int (*debugger_iabr_match)(struct pt_regs *regs);
-int (*debugger_dabr_match)(struct pt_regs *regs);
-void (*debugger_fault_handler)(struct pt_regs *regs);
+#ifdef CONFIG_DEBUGGER
+int (*__debugger)(struct pt_regs *regs);
+int (*__debugger_bpt)(struct pt_regs *regs);
+int (*__debugger_sstep)(struct pt_regs *regs);
+int (*__debugger_iabr_match)(struct pt_regs *regs);
+int (*__debugger_dabr_match)(struct pt_regs *regs);
+int (*__debugger_fault_handler)(struct pt_regs *regs);
+
+EXPORT_SYMBOL(__debugger);
+EXPORT_SYMBOL(__debugger_bpt);
+EXPORT_SYMBOL(__debugger_sstep);
+EXPORT_SYMBOL(__debugger_iabr_match);
+EXPORT_SYMBOL(__debugger_dabr_match);
+EXPORT_SYMBOL(__debugger_fault_handler);
 #endif
 
 /*
@@ -88,11 +95,9 @@ static void
 _exception(int signr, siginfo_t *info, struct pt_regs *regs)
 {
 	if (!user_mode(regs)) {
-#ifdef CONFIG_DEBUG_KERNEL
-		if (debugger)
-			debugger(regs);
-#endif
-		die("Exception in kernel mode", regs, signr);
+		if (debugger(regs))
+			return;
+		die("Exception in kernel mode\n", regs, signr);
 	}
 
 	force_sig_info(signr, info, current);
@@ -146,12 +151,8 @@ SystemResetException(struct pt_regs *regs)
 	}
 #endif
 
-#ifdef CONFIG_DEBUG_KERNEL
-	if (debugger)
-		debugger(regs);
-	else
-#endif
-		panic("System Reset");
+	if (!debugger(regs))
+		die("System Reset", regs, 0);
 
 	/* Must die if the interrupt is not recoverable */
 	if (!(regs->msr & MSR_RI))
@@ -228,23 +229,12 @@ MachineCheckException(struct pt_regs *regs)
 	}
 #endif
 
-#ifdef CONFIG_DEBUG_KERNEL
-	if (debugger_fault_handler) {
-		debugger_fault_handler(regs);
+	if (debugger_fault_handler(regs))
 		return;
-	}
-	if (debugger)
-		debugger(regs);
-#endif
-	console_verbose();
-	spin_lock_irq(&die_lock);
-	bust_spinlocks(1);
-	printk("Machine check in kernel mode.\n");
-	printk("Caused by (from SRR1=%lx): ", regs->msr);
-	show_regs(regs);
-	bust_spinlocks(0);
-	spin_unlock_irq(&die_lock);
-	panic("Unrecoverable Machine Check");
+	if (debugger(regs))
+		return;
+
+	die("Machine check in kernel mode", regs, 0);
 }
 
 void
@@ -267,10 +257,8 @@ InstructionBreakpointException(struct pt_regs *regs)
 {
 	siginfo_t info;
 
-#ifdef CONFIG_DEBUG_KERNEL
-	if (debugger_iabr_match && debugger_iabr_match(regs))
+	if (debugger_iabr_match(regs))
 		return;
-#endif
 	info.si_signo = SIGTRAP;
 	info.si_errno = 0;
 	info.si_code = TRAP_BRKPT;
@@ -372,12 +360,8 @@ ProgramCheckException(struct pt_regs *regs)
 {
 	siginfo_t info;
 
-#ifdef CONFIG_DEBUG_KERNEL
-	if (debugger_fault_handler) {
-		debugger_fault_handler(regs);
+	if (debugger_fault_handler(regs))
 		return;
-	}
-#endif
 
 	if (regs->msr & 0x100000) {
 		/* IEEE FP exception */
@@ -394,10 +378,9 @@ ProgramCheckException(struct pt_regs *regs)
 	} else if (regs->msr & 0x20000) {
 		/* trap exception */
 
-#ifdef CONFIG_DEBUG_KERNEL
-		if (debugger_bpt && debugger_bpt(regs))
+		if (debugger_bpt(regs))
 			return;
-#endif
+
 		if (check_bug_trap(regs)) {
 			regs->nip += 4;
 			return;
@@ -421,17 +404,13 @@ ProgramCheckException(struct pt_regs *regs)
 void
 KernelFPUnavailableException(struct pt_regs *regs)
 {
-	printk("Illegal floating point used in kernel (task=0x%p, "
-		"pc=0x%016lx, trap=0x%lx)\n", current, regs->nip, regs->trap);
-	panic("Unrecoverable FP Unavailable Exception in Kernel");
+	die("Unrecoverable FP Unavailable Exception in Kernel", regs, 0);
 }
 
 void
 KernelAltivecUnavailableException(struct pt_regs *regs)
 {
-	printk("Illegal VMX/Altivec used in kernel (task=0x%p, "
-		"pc=0x%016lx, trap=0x%lx)\n", current, regs->nip, regs->trap);
-	panic("Unrecoverable VMX/Altivec Unavailable Exception in Kernel");
+	die("Unrecoverable VMX/Altivec Unavailable Exception in Kernel", regs, 0);
 }
 
 void
@@ -441,10 +420,9 @@ SingleStepException(struct pt_regs *regs)
 
 	regs->msr &= ~MSR_SE;  /* Turn off 'trace' bit */
 
-#ifdef CONFIG_DEBUG_KERNEL
-	if (debugger_sstep && debugger_sstep(regs))
+	if (debugger_sstep(regs))
 		return;
-#endif
+
 	info.si_signo = SIGTRAP;
 	info.si_errno = 0;
 	info.si_code = TRAP_TRACE;

arch/ppc64/kernel/xics.c

@@ -353,11 +353,11 @@ irqreturn_t xics_ipi_action(int irq, void *dev_id, struct pt_regs *regs)
 			smp_message_recv(PPC_MSG_MIGRATE_TASK, regs);
 		}
 #endif
-#ifdef CONFIG_XMON
-		if (test_and_clear_bit(PPC_MSG_XMON_BREAK,
+#ifdef CONFIG_DEBUGGER
+		if (test_and_clear_bit(PPC_MSG_DEBUGGER_BREAK,
 				       &xics_ipi_message[cpu].value)) {
 			mb();
-			smp_message_recv(PPC_MSG_XMON_BREAK, regs);
+			smp_message_recv(PPC_MSG_DEBUGGER_BREAK, regs);
 		}
 #endif
 	}

arch/ppc64/mm/fault.c

@@ -37,12 +37,6 @@
 #include <asm/system.h>
 #include <asm/uaccess.h>
 
-#include <asm/ppcdebug.h>
-
-#ifdef CONFIG_DEBUG_KERNEL
-int debugger_kernel_faults = 1;
-#endif
-
 void bad_page_fault(struct pt_regs *, unsigned long, int);
 
 /*
@@ -60,13 +54,10 @@ void do_page_fault(struct pt_regs *regs, unsigned long address,
 	unsigned long code = SEGV_MAPERR;
 	unsigned long is_write = error_code & 0x02000000;
 
-#ifdef CONFIG_DEBUG_KERNEL
-	if (debugger_fault_handler && (regs->trap == 0x300 ||
-				       regs->trap == 0x380)) {
-		debugger_fault_handler(regs);
-		return;
+	if (regs->trap == 0x300 || regs->trap == 0x380) {
+		if (debugger_fault_handler(regs))
+			return;
 	}
-#endif
 
 	/* On a kernel SLB miss we can only check for a valid exception entry */
 	if (!user_mode(regs) && (regs->trap == 0x380)) {
@@ -74,13 +65,10 @@ void do_page_fault(struct pt_regs *regs, unsigned long address,
 		return;
 	}
 
-#ifdef CONFIG_DEBUG_KERNEL
 	if (error_code & 0x00400000) {
-		/* DABR match */
 		if (debugger_dabr_match(regs))
 			return;
 	}
-#endif
 
 	if (in_atomic() || mm == NULL) {
 		bad_page_fault(regs, address, SIGSEGV);
@@ -149,11 +137,6 @@ void do_page_fault(struct pt_regs *regs, unsigned long address,
 		info.si_errno = 0;
 		info.si_code = code;
 		info.si_addr = (void *) address;
-#ifdef CONFIG_XMON
-		ifppcdebug(PPCDBG_SIGNALXMON)
-			PPCDBG_ENTER_DEBUGGER_REGS(regs);
-#endif
-
 		force_sig_info(SIGSEGV, &info, current);
 		return;
 	}
@@ -207,9 +190,7 @@ bad_page_fault(struct pt_regs *regs, unsigned long address, int sig)
 	}
 
 	/* kernel has accessed a bad area */
-#ifdef CONFIG_DEBUG_KERNEL
-	if (debugger_kernel_faults && debugger)
-		debugger(regs);
-#endif
+	if (debugger(regs))
+		return;
 	die("Kernel access of bad area", regs, sig);
 }

arch/ppc64/mm/init.c

@@ -59,6 +59,7 @@
 #include <asm/cputable.h>
 #include <asm/ppcdebug.h>
 #include <asm/sections.h>
+#include <asm/system.h>
 
 #ifdef CONFIG_PPC_ISERIES
 #include <asm/iSeries/iSeries_dma.h>
@@ -691,11 +692,7 @@ void __init do_init_bootmem(void)
 	bootmap_pages = bootmem_bootmap_pages(total_pages);
 
 	start = (unsigned long)__a2p(lmb_alloc(bootmap_pages<<PAGE_SHIFT, PAGE_SIZE));
-	if (start == 0) {
-		udbg_printf("do_init_bootmem: failed to allocate a bitmap.\n");
-		udbg_printf("\tbootmap_pages = 0x%lx.\n", bootmap_pages);
-		PPCDBG_ENTER_DEBUGGER(); 
-	}
+	BUG_ON(!start);
 
 	boot_mapsize = init_bootmem(start >> PAGE_SHIFT, total_pages);
 

arch/ppc64/xmon/start.c

@@ -11,31 +11,23 @@
 #include <linux/kernel.h>
 #include <linux/errno.h>
 #include <linux/sysrq.h>
+#include <linux/init.h>
 #include <asm/machdep.h>
 #include <asm/io.h>
 #include <asm/page.h>
 #include <asm/prom.h>
 #include <asm/processor.h>
 #include <asm/udbg.h>
-
-extern void xmon_printf(const char *fmt, ...);
-
-#define TB_SPEED	25000000
-
-static inline unsigned int readtb(void)
-{
-	unsigned int ret;
-
-	asm volatile("mftb %0" : "=r" (ret) :);
-	return ret;
-}
+#include <asm/system.h>
 
 #ifdef CONFIG_MAGIC_SYSRQ
 
 static void sysrq_handle_xmon(int key, struct pt_regs *pt_regs,
 			      struct tty_struct *tty) 
 {
-	xmon(pt_regs);
+	/* ensure xmon is enabled */
+	xmon_init();
+	debugger(pt_regs);
 }
 
 static struct sysrq_key_op sysrq_xmon_op = 
@@ -45,16 +37,13 @@ static struct sysrq_key_op sysrq_xmon_op =
 	.action_msg =	"Entering xmon\n",
 };
 
-#endif /* CONFIG_MAGIC_SYSRQ */
-
-void
-xmon_map_scc(void)
+static int __init setup_xmon_sysrq(void)
 {
-#ifdef CONFIG_MAGIC_SYSRQ
-	/* This maybe isn't the best place to register sysrq 'x' */
 	__sysrq_put_key_op('x', &sysrq_xmon_op);
-#endif /* CONFIG_MAGIC_SYSRQ */
+	return 0;
 }
+__initcall(setup_xmon_sysrq);
+#endif /* CONFIG_MAGIC_SYSRQ */
 
 int
 xmon_write(void *handle, void *ptr, int nb)
@@ -62,8 +51,6 @@ xmon_write(void *handle, void *ptr, int nb)
 	return udbg_write(ptr, nb);
 }
 
-int xmon_wants_key;
-
 int
 xmon_read(void *handle, void *ptr, int nb)
 {
@@ -80,11 +67,6 @@ void *xmon_stdin;
 void *xmon_stdout;
 void *xmon_stderr;
 
-void
-xmon_init(void)
-{
-}
-
 int
 xmon_putc(int c, void *f)
 {

arch/ppc64/xmon/xmon.c

@@ -73,11 +73,10 @@ static struct bpt iabr;
 static unsigned bpinstr = 0x7fe00008;	/* trap */
 
 /* Prototypes */
-extern void (*debugger_fault_handler)(struct pt_regs *);
 static int cmds(struct pt_regs *);
 static int mread(unsigned long, void *, int);
 static int mwrite(unsigned long, void *, int);
-static void handle_fault(struct pt_regs *);
+static int handle_fault(struct pt_regs *);
 static void byterev(unsigned char *, int);
 static void memex(void);
 static int bsesc(void);
@@ -235,7 +234,7 @@ static inline void disable_surveillance(void)
 #endif
 }
 
-void
+int
 xmon(struct pt_regs *excp)
 {
 	struct pt_regs regs;
@@ -342,6 +341,8 @@ xmon(struct pt_regs *excp)
 	cpu_clear(smp_processor_id(), cpus_in_xmon);
 #endif /* CONFIG_SMP */
 	set_msrd(msr);		/* restore interrupt enable */
+
+	return 0;
 }
 
 int
@@ -627,7 +628,7 @@ static void cpu_cmd(void)
 		printf("stopping all cpus\n");
 		/* interrupt other cpu(s) */
 		cpu = MSG_ALL_BUT_SELF;
-		smp_send_xmon_break(cpu);
+		smp_send_debugger_break(cpu);
 		return;
 	}
 	termch = cmd;
@@ -1052,8 +1053,8 @@ cacheflush(void)
 	nflush = 1;
 	scanhex(&nflush);
 	nflush = (nflush + L1_CACHE_BYTES - 1) / L1_CACHE_BYTES;
-	if( setjmp(bus_error_jmp) == 0 ) {
-		debugger_fault_handler = handle_fault;
+	if (setjmp(bus_error_jmp) == 0) {
+		__debugger_fault_handler = handle_fault;
 		sync();
 
 		if (cmd != 'i') {
@@ -1067,7 +1068,7 @@ cacheflush(void)
 		/* wait a little while to see if we get a machine check */
 		__delay(200);
 	}
-	debugger_fault_handler = 0;
+	__debugger_fault_handler = 0;
 }
 
 unsigned long
@@ -1088,7 +1089,7 @@ read_spr(int n)
 	code = (unsigned long (*)(void)) opd;
 
 	if (setjmp(bus_error_jmp) == 0) {
-		debugger_fault_handler = handle_fault;
+		__debugger_fault_handler = handle_fault;
 		sync();
 
 		ret = code();
@@ -1100,7 +1101,7 @@ read_spr(int n)
 		printf("*** Error reading spr %x\n", n);
 	}
 
-	debugger_fault_handler = 0;
+	__debugger_fault_handler = 0;
 
 	return ret;
 }
@@ -1122,7 +1123,7 @@ write_spr(int n, unsigned long val)
 	code = (unsigned long (*)(unsigned long)) opd;
 
 	if (setjmp(bus_error_jmp) == 0) {
-		debugger_fault_handler = handle_fault;
+		__debugger_fault_handler = handle_fault;
 		sync();
 
 		code(val);
@@ -1134,7 +1135,7 @@ write_spr(int n, unsigned long val)
 		printf("*** Error writing spr %x\n", n);
 	}
 
-	debugger_fault_handler = 0;
+	__debugger_fault_handler = 0;
 }
 
 static unsigned long regno;
@@ -1213,7 +1214,7 @@ mread(unsigned long adrs, void *buf, int size)
 
 	n = 0;
 	if (setjmp(bus_error_jmp) == 0) {
-		debugger_fault_handler = handle_fault;
+		__debugger_fault_handler = handle_fault;
 		sync();
 		p = (char *)adrs;
 		q = (char *)buf;
@@ -1238,7 +1239,7 @@ mread(unsigned long adrs, void *buf, int size)
 		__delay(200);
 		n = size;
 	}
-	debugger_fault_handler = 0;
+	__debugger_fault_handler = 0;
 	return n;
 }
 
@@ -1250,7 +1251,7 @@ mwrite(unsigned long adrs, void *buf, int size)
 
 	n = 0;
 	if (setjmp(bus_error_jmp) == 0) {
-		debugger_fault_handler = handle_fault;
+		__debugger_fault_handler = handle_fault;
 		sync();
 		p = (char *) adrs;
 		q = (char *) buf;
@@ -1277,14 +1278,14 @@ mwrite(unsigned long adrs, void *buf, int size)
 	} else {
 		printf("*** Error writing address %x\n", adrs + n);
 	}
-	debugger_fault_handler = 0;
+	__debugger_fault_handler = 0;
 	return n;
 }
 
 static int fault_type;
 static char *fault_chars[] = { "--", "**", "##" };
 
-static void
+static int
 handle_fault(struct pt_regs *regs)
 {
 	switch (regs->trap) {
@@ -1300,6 +1301,8 @@ handle_fault(struct pt_regs *regs)
 	}
 
 	longjmp(bus_error_jmp, 1);
+
+	return 0;
 }
 
 #define SWAP(a, b, t)	((t) = (a), (a) = (b), (b) = (t))
@@ -1913,7 +1916,7 @@ void __xmon_print_symbol(const char *fmt, unsigned long address)
 	char namebuf[128];
 
 	if (setjmp(bus_error_jmp) == 0) {
-		debugger_fault_handler = handle_fault;
+		__debugger_fault_handler = handle_fault;
 		sync();
 		name = kallsyms_lookup(address, &size, &offset, &modname,
 				       namebuf);
@@ -1924,7 +1927,7 @@ void __xmon_print_symbol(const char *fmt, unsigned long address)
 		name = "symbol lookup failed";
 	}
 
-	debugger_fault_handler = 0;
+	__debugger_fault_handler = 0;
 
 	if (!name) {
 		char addrstr[sizeof("0x%lx") + (BITS_PER_LONG*3/10)];
@@ -2037,6 +2040,15 @@ static void dump_stab(void)
 	}
 }
 
+void xmon_init(void)
+{
+	__debugger = xmon;
+	__debugger_bpt = xmon_bpt;
+	__debugger_sstep = xmon_sstep;
+	__debugger_iabr_match = xmon_iabr_match;
+	__debugger_dabr_match = xmon_dabr_match;
+}
+
 void dump_segments(void)
 {
 	if (cur_cpu_spec->cpu_features & CPU_FTR_SLB)

include/asm-ppc64/ppcdebug.h

@@ -95,11 +95,6 @@ extern char *trace_names[64];
 #define ppcdebugset(FLAGS) (udbg_ifdebug(FLAGS))
 #define PPCDBG_BINFMT (test_thread_flag(TIF_32BIT) ? PPCDBG_BINFMT32 : PPCDBG_BINFMT64)
 
-#ifdef CONFIG_XMON
-#define PPCDBG_ENTER_DEBUGGER() xmon(0)
-#define PPCDBG_ENTER_DEBUGGER_REGS(X) xmon(X)
-#endif
-
 #else
 #define PPCDBG(...) do {;} while (0)
 #define PPCDBGCALL(FLAGS,FUNCTION) do {;} while (0)
@@ -107,12 +102,4 @@ extern char *trace_names[64];
 #define ppcdebugset(FLAGS) (0)
 #endif /* CONFIG_PPCDBG */
 
-#ifndef PPCDBG_ENTER_DEBUGGER
-#define PPCDBG_ENTER_DEBUGGER() do {;} while(0)
-#endif
-
-#ifndef PPCDBG_ENTER_DEBUGGER_REGS
-#define PPCDBG_ENTER_DEBUGGER_REGS(A) do {;} while(0)
-#endif
-
 #endif /*__PPCDEBUG_H */

include/asm-ppc64/smp.h

@@ -29,8 +29,7 @@
 #ifdef CONFIG_SMP
 
 extern void smp_message_pass(int target, int msg, unsigned long data, int wait);
-extern void smp_send_tlb_invalidate(int);
-extern void smp_send_xmon_break(int cpu);
+extern void smp_send_debugger_break(int cpu);
 struct pt_regs;
 extern void smp_message_recv(int, struct pt_regs *);
 
@@ -63,17 +62,22 @@ extern cpumask_t cpu_available_map;
  * in /proc/interrupts will be wrong!!! --Troy */
 #define PPC_MSG_CALL_FUNCTION   0
 #define PPC_MSG_RESCHEDULE      1
+/* This is unused now */
+#if 0
 #define PPC_MSG_MIGRATE_TASK    2
-#define PPC_MSG_XMON_BREAK      3
+#endif
+#define PPC_MSG_DEBUGGER_BREAK  3
 
 void smp_init_iSeries(void);
 void smp_init_pSeries(void);
 
 #endif /* !(CONFIG_SMP) */
-#endif /* __ASSEMBLY__ */
 
 #define get_hard_smp_processor_id(CPU) (paca[(CPU)].xHwProcNum)
-#define set_hard_smp_processor_id(CPU, VAL) do { (paca[(CPU)].xHwProcNum = VAL); } while (0)
+#define set_hard_smp_processor_id(CPU, VAL) \
+	do { (paca[(CPU)].xHwProcNum = VAL); } while (0)
+
+#endif /* __ASSEMBLY__ */
 
 #endif /* !(_PPC64_SMP_H) */
 #endif /* __KERNEL__ */

include/asm-ppc64/system.h

@@ -9,6 +9,7 @@
  */
 
 #include <linux/config.h>
+#include <linux/compiler.h>
 #include <asm/page.h>
 #include <asm/processor.h>
 #include <asm/hw_irq.h>
@@ -52,31 +53,41 @@
 #define smp_read_barrier_depends()  do { } while(0)
 #endif /* CONFIG_SMP */
 
-#ifdef CONFIG_DEBUG_KERNEL
-extern void (*debugger)(struct pt_regs *regs);
-extern int (*debugger_bpt)(struct pt_regs *regs);
-extern int (*debugger_sstep)(struct pt_regs *regs);
-extern int (*debugger_iabr_match)(struct pt_regs *regs);
-extern int (*debugger_dabr_match)(struct pt_regs *regs);
-extern void (*debugger_fault_handler)(struct pt_regs *regs);
+#ifdef CONFIG_DEBUGGER
+
+extern int (*__debugger)(struct pt_regs *regs);
+extern int (*__debugger_bpt)(struct pt_regs *regs);
+extern int (*__debugger_sstep)(struct pt_regs *regs);
+extern int (*__debugger_iabr_match)(struct pt_regs *regs);
+extern int (*__debugger_dabr_match)(struct pt_regs *regs);
+extern int (*__debugger_fault_handler)(struct pt_regs *regs);
+
+#define DEBUGGER_BOILERPLATE(__NAME) \
+static inline int __NAME(struct pt_regs *regs) \
+{ \
+	if (unlikely(__ ## __NAME)) \
+		return __ ## __NAME(regs); \
+	return 0; \
+}
+
+DEBUGGER_BOILERPLATE(debugger)
+DEBUGGER_BOILERPLATE(debugger_bpt)
+DEBUGGER_BOILERPLATE(debugger_sstep)
+DEBUGGER_BOILERPLATE(debugger_iabr_match)
+DEBUGGER_BOILERPLATE(debugger_dabr_match)
+DEBUGGER_BOILERPLATE(debugger_fault_handler)
+
+#ifdef CONFIG_XMON
+extern void xmon_init(void);
+#endif
+
 #else
-#define debugger(regs)			do { } while (0)
+#define debugger(regs)			0
 #define debugger_bpt(regs)		0
 #define debugger_sstep(regs)		0
 #define debugger_iabr_match(regs)	0
 #define debugger_dabr_match(regs)	0
-#define debugger_fault_handler		((void (*)(struct pt_regs *))0)
-#endif
-
-#ifdef CONFIG_XMON
-extern void xmon_irq(int, void *, struct pt_regs *);
-
-extern void xmon(struct pt_regs *regs);
-extern int xmon_bpt(struct pt_regs *regs);
-extern int xmon_sstep(struct pt_regs *regs);
-extern int xmon_iabr_match(struct pt_regs *regs);
-extern int xmon_dabr_match(struct pt_regs *regs);
-extern void (*xmon_fault_handler)(struct pt_regs *regs);
+#define debugger_fault_handler(regs)	0
 #endif
 
 extern void show_regs(struct pt_regs * regs);

include/asm-ppc64/xmon.h

-#ifndef __PPC_XMON_H
-#define __PPC_XMON_H
-#ifdef __KERNEL__
-
-struct pt_regs;
-
-extern void xmon(struct pt_regs *excp);
-extern void xmon_printf(const char *fmt, ...);
-extern void xmon_map_scc(void);
-extern int xmon_bpt(struct pt_regs *regs);
-extern int xmon_sstep(struct pt_regs *regs);
-extern int xmon_iabr_match(struct pt_regs *regs);
-extern int xmon_dabr_match(struct pt_regs *regs);
-extern void (*xmon_fault_handler)(struct pt_regs *regs);
-
-#endif
-#endif