arch/mips/kernel/kgdb.c - kernel/skids - Git at Google

 /*
  *  Originally written by Glenn Engel, Lake Stevens Instrument Division
  *
  *  Contributed by HP Systems
  *
  *  Modified for Linux/MIPS (and MIPS in general) by Andreas Busse
  *  Send complaints, suggestions etc. to <andy@waldorf-gmbh.de>
  *
  *  Copyright (C) 1995 Andreas Busse
  *
  *  Copyright (C) 2003 MontaVista Software Inc.
  *  Author: Jun Sun, jsun@mvista.com or jsun@junsun.net
  *
  *  Copyright (C) 2004-2005 MontaVista Software Inc.
  *  Author: Manish Lachwani, mlachwani@mvista.com or manish@koffee-break.com
  *
  *  Copyright (C) 2007-2008 Wind River Systems, Inc.
  *  Author/Maintainer: Jason Wessel, jason.wessel@windriver.com
  *
  *  This file is licensed under the terms of the GNU General Public License
  *  version 2. This program is licensed "as is" without any warranty of any
  *  kind, whether express or implied.
  */

 #include <linux/ptrace.h>		/* for linux pt_regs struct */
 #include <linux/kgdb.h>
 #include <linux/kdebug.h>
 #include <linux/sched.h>
 #include <linux/smp.h>
 #include <asm/inst.h>
 #include <asm/fpu.h>
 #include <asm/cacheflush.h>
 #include <asm/processor.h>
 #include <asm/sigcontext.h>

 static struct hard_trap_info {
 	unsigned char tt;	/* Trap type code for MIPS R3xxx and R4xxx */
 	unsigned char signo;	/* Signal that we map this trap into */
 } hard_trap_info[] = {
 	{ 6, SIGBUS },		/* instruction bus error */
 	{ 7, SIGBUS },		/* data bus error */
 	{ 9, SIGTRAP },		/* break */
 /*	{ 11, SIGILL },	*/	/* CPU unusable */
 	{ 12, SIGFPE },		/* overflow */
 	{ 13, SIGTRAP },	/* trap */
 	{ 14, SIGSEGV },	/* virtual instruction cache coherency */
 	{ 15, SIGFPE },		/* floating point exception */
 	{ 23, SIGSEGV },	/* watch */
 	{ 31, SIGSEGV },	/* virtual data cache coherency */
 	{ 0, 0}			/* Must be last */
 };

 void arch_kgdb_breakpoint(void)
 {
 	__asm__ __volatile__(
 		".globl breakinst\n\t"
 		".set\tnoreorder\n\t"
 		"nop\n"
 		"breakinst:\tbreak\n\t"
 		"nop\n\t"
 		".set\treorder");
 }

 static void kgdb_call_nmi_hook(void *ignored)
 {
 	kgdb_nmicallback(raw_smp_processor_id(), NULL);
 }

 void kgdb_roundup_cpus(unsigned long flags)
 {
 	local_irq_enable();
 	smp_call_function(kgdb_call_nmi_hook, NULL, 0);
 	local_irq_disable();
 }

 static int compute_signal(int tt)
 {
 	struct hard_trap_info *ht;

 	for (ht = hard_trap_info; ht->tt && ht->signo; ht++)
 		if (ht->tt == tt)
 			return ht->signo;

 	return SIGHUP;		/* default for things we don't know about */
 }

 void pt_regs_to_gdb_regs(unsigned long *gdb_regs, struct pt_regs *regs)
 {
 	int reg;

 #if (KGDB_GDB_REG_SIZE == 32)
 	u32 *ptr = (u32 *)gdb_regs;
 #else
 	u64 *ptr = (u64 *)gdb_regs;
 #endif

 	for (reg = 0; reg < 32; reg++)
 		*(ptr++) = regs->regs[reg];

 	*(ptr++) = regs->cp0_status;
 	*(ptr++) = regs->lo;
 	*(ptr++) = regs->hi;
 	*(ptr++) = regs->cp0_badvaddr;
 	*(ptr++) = regs->cp0_cause;
 	*(ptr++) = regs->cp0_epc;

 	/* FP REGS */
 	if (!(current && (regs->cp0_status & ST0_CU1)))
 		return;

 	save_fp(current);
 	for (reg = 0; reg < 32; reg++)
 		*(ptr++) = current->thread.fpu.fpr[reg];
 }

 void gdb_regs_to_pt_regs(unsigned long *gdb_regs, struct pt_regs *regs)
 {
 	int reg;

 #if (KGDB_GDB_REG_SIZE == 32)
 	const u32 *ptr = (u32 *)gdb_regs;
 #else
 	const u64 *ptr = (u64 *)gdb_regs;
 #endif

 	for (reg = 0; reg < 32; reg++)
 		regs->regs[reg] = *(ptr++);

 	regs->cp0_status = *(ptr++);
 	regs->lo = *(ptr++);
 	regs->hi = *(ptr++);
 	regs->cp0_badvaddr = *(ptr++);
 	regs->cp0_cause = *(ptr++);
 	regs->cp0_epc = *(ptr++);

 	/* FP REGS from current */
 	if (!(current && (regs->cp0_status & ST0_CU1)))
 		return;

 	for (reg = 0; reg < 32; reg++)
 		current->thread.fpu.fpr[reg] = *(ptr++);
 	restore_fp(current);
 }

 /*
  * Similar to regs_to_gdb_regs() except that process is sleeping and so
  * we may not be able to get all the info.
  */
 void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *p)
 {
 	int reg;
 	struct thread_info *ti = task_thread_info(p);
 	unsigned long ksp = (unsigned long)ti + THREAD_SIZE - 32;
 	struct pt_regs *regs = (struct pt_regs *)ksp - 1;
 #if (KGDB_GDB_REG_SIZE == 32)
 	u32 *ptr = (u32 *)gdb_regs;
 #else
 	u64 *ptr = (u64 *)gdb_regs;
 #endif

 	for (reg = 0; reg < 16; reg++)
 		*(ptr++) = regs->regs[reg];

 	/* S0 - S7 */
 	for (reg = 16; reg < 24; reg++)
 		*(ptr++) = regs->regs[reg];

 	for (reg = 24; reg < 28; reg++)
 		*(ptr++) = 0;

 	/* GP, SP, FP, RA */
 	for (reg = 28; reg < 32; reg++)
 		*(ptr++) = regs->regs[reg];

 	*(ptr++) = regs->cp0_status;
 	*(ptr++) = regs->lo;
 	*(ptr++) = regs->hi;
 	*(ptr++) = regs->cp0_badvaddr;
 	*(ptr++) = regs->cp0_cause;
 	*(ptr++) = regs->cp0_epc;
 }

 void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long pc)
 {
 	regs->cp0_epc = pc;
 }

 /*
  * Calls linux_debug_hook before the kernel dies. If KGDB is enabled,
  * then try to fall into the debugger
  */
 static int kgdb_mips_notify(struct notifier_block *self, unsigned long cmd,
 			    void *ptr)
 {
 	struct die_args *args = (struct die_args *)ptr;
 	struct pt_regs *regs = args->regs;
 	int trap = (regs->cp0_cause & 0x7c) >> 2;

 	/* Userpace events, ignore. */
 	if (user_mode(regs))
 		return NOTIFY_DONE;

 	if (atomic_read(&kgdb_active) != -1)
 		kgdb_nmicallback(smp_processor_id(), regs);

 	if (kgdb_handle_exception(trap, compute_signal(trap), cmd, regs))
 		return NOTIFY_DONE;

 	if (atomic_read(&kgdb_setting_breakpoint))
 		if ((trap == 9) && (regs->cp0_epc == (unsigned long)breakinst))
 			regs->cp0_epc += 4;

 	/* In SMP mode, __flush_cache_all does IPI */
 	local_irq_enable();
 	__flush_cache_all();

 	return NOTIFY_STOP;
 }

 #ifdef CONFIG_KGDB_LOW_LEVEL_TRAP
 int kgdb_ll_trap(int cmd, const char *str,
 		 struct pt_regs *regs, long err, int trap, int sig)
 {
 	struct die_args args = {
 		.regs	= regs,
 		.str	= str,
 		.err	= err,
 		.trapnr	= trap,
 		.signr	= sig,

 	};

 	if (!kgdb_io_module_registered)
 		return NOTIFY_DONE;

 	return kgdb_mips_notify(NULL, cmd, &args);
 }
 #endif /* CONFIG_KGDB_LOW_LEVEL_TRAP */

 static struct notifier_block kgdb_notifier = {
 	.notifier_call = kgdb_mips_notify,
 };

 /*
  * Handle the 's' and 'c' commands
  */
 int kgdb_arch_handle_exception(int vector, int signo, int err_code,
 			       char *remcom_in_buffer, char *remcom_out_buffer,
 			       struct pt_regs *regs)
 {
 	char *ptr;
 	unsigned long address;
 	int cpu = smp_processor_id();

 	switch (remcom_in_buffer[0]) {
 	case 's':
 	case 'c':
 		/* handle the optional parameter */
 		ptr = &remcom_in_buffer[1];
 		if (kgdb_hex2long(&ptr, &address))
 			regs->cp0_epc = address;

 		atomic_set(&kgdb_cpu_doing_single_step, -1);
 		if (remcom_in_buffer[0] == 's')
 			atomic_set(&kgdb_cpu_doing_single_step, cpu);

 		return 0;
 	}

 	return -1;
 }

 struct kgdb_arch arch_kgdb_ops;

 /*
  * We use kgdb_early_setup so that functions we need to call now don't
  * cause trouble when called again later.
  */
 int kgdb_arch_init(void)
 {
 	union mips_instruction insn = {
 		.r_format = {
 			.opcode = spec_op,
 			.func   = break_op,
 		}
 	};
 	memcpy(arch_kgdb_ops.gdb_bpt_instr, insn.byte, BREAK_INSTR_SIZE);

 	register_die_notifier(&kgdb_notifier);

 	return 0;
 }

 /*
  *	kgdb_arch_exit - Perform any architecture specific uninitalization.
  *
  *	This function will handle the uninitalization of any architecture
  *	specific callbacks, for dynamic registration and unregistration.
  */
 void kgdb_arch_exit(void)
 {
 	unregister_die_notifier(&kgdb_notifier);
 }
	/*
	* Originally written by Glenn Engel, Lake Stevens Instrument Division
	*
	* Contributed by HP Systems
	*
	* Modified for Linux/MIPS (and MIPS in general) by Andreas Busse
	* Send complaints, suggestions etc. to <andy@waldorf-gmbh.de>
	*
	* Copyright (C) 1995 Andreas Busse
	*
	* Copyright (C) 2003 MontaVista Software Inc.
	* Author: Jun Sun, jsun@mvista.com or jsun@junsun.net
	*
	* Copyright (C) 2004-2005 MontaVista Software Inc.
	* Author: Manish Lachwani, mlachwani@mvista.com or manish@koffee-break.com
	*
	* Copyright (C) 2007-2008 Wind River Systems, Inc.
	* Author/Maintainer: Jason Wessel, jason.wessel@windriver.com
	*
	* This file is licensed under the terms of the GNU General Public License
	* version 2. This program is licensed "as is" without any warranty of any
	* kind, whether express or implied.
	*/

	#include <linux/ptrace.h> /* for linux pt_regs struct */
	#include <linux/kgdb.h>
	#include <linux/kdebug.h>
	#include <linux/sched.h>
	#include <linux/smp.h>
	#include <asm/inst.h>
	#include <asm/fpu.h>
	#include <asm/cacheflush.h>
	#include <asm/processor.h>
	#include <asm/sigcontext.h>

	static struct hard_trap_info {
	unsigned char tt; /* Trap type code for MIPS R3xxx and R4xxx */
	unsigned char signo; /* Signal that we map this trap into */
	} hard_trap_info[] = {
	{ 6, SIGBUS }, /* instruction bus error */
	{ 7, SIGBUS }, /* data bus error */
	{ 9, SIGTRAP }, /* break */
	/* { 11, SIGILL }, / / CPU unusable */
	{ 12, SIGFPE }, /* overflow */
	{ 13, SIGTRAP }, /* trap */
	{ 14, SIGSEGV }, /* virtual instruction cache coherency */
	{ 15, SIGFPE }, /* floating point exception */
	{ 23, SIGSEGV }, /* watch */
	{ 31, SIGSEGV }, /* virtual data cache coherency */
	{ 0, 0} /* Must be last */
	};

	void arch_kgdb_breakpoint(void)
	{
	__asm__ __volatile__(
	".globl breakinst\n\t"
	".set\tnoreorder\n\t"
	"nop\n"
	"breakinst:\tbreak\n\t"
	"nop\n\t"
	".set\treorder");
	}

	static void kgdb_call_nmi_hook(void *ignored)
	{
	kgdb_nmicallback(raw_smp_processor_id(), NULL);
	}

	void kgdb_roundup_cpus(unsigned long flags)
	{
	local_irq_enable();
	smp_call_function(kgdb_call_nmi_hook, NULL, 0);
	local_irq_disable();
	}

	static int compute_signal(int tt)
	{
	struct hard_trap_info *ht;

	for (ht = hard_trap_info; ht->tt && ht->signo; ht++)
	if (ht->tt == tt)
	return ht->signo;

	return SIGHUP; /* default for things we don't know about */
	}

	void pt_regs_to_gdb_regs(unsigned long gdb_regs, struct pt_regs regs)
	{
	int reg;

	#if (KGDB_GDB_REG_SIZE == 32)
	u32 ptr = (u32 )gdb_regs;
	#else
	u64 ptr = (u64 )gdb_regs;
	#endif

	for (reg = 0; reg < 32; reg++)
	*(ptr++) = regs->regs[reg];

	*(ptr++) = regs->cp0_status;
	*(ptr++) = regs->lo;
	*(ptr++) = regs->hi;
	*(ptr++) = regs->cp0_badvaddr;
	*(ptr++) = regs->cp0_cause;
	*(ptr++) = regs->cp0_epc;

	/* FP REGS */
	if (!(current && (regs->cp0_status & ST0_CU1)))
	return;

	save_fp(current);
	for (reg = 0; reg < 32; reg++)
	*(ptr++) = current->thread.fpu.fpr[reg];
	}

	void gdb_regs_to_pt_regs(unsigned long gdb_regs, struct pt_regs regs)
	{
	int reg;

	#if (KGDB_GDB_REG_SIZE == 32)
	const u32 ptr = (u32 )gdb_regs;
	#else
	const u64 ptr = (u64 )gdb_regs;
	#endif

	for (reg = 0; reg < 32; reg++)
	regs->regs[reg] = *(ptr++);

	regs->cp0_status = *(ptr++);
	regs->lo = *(ptr++);
	regs->hi = *(ptr++);
	regs->cp0_badvaddr = *(ptr++);
	regs->cp0_cause = *(ptr++);
	regs->cp0_epc = *(ptr++);

	/* FP REGS from current */
	if (!(current && (regs->cp0_status & ST0_CU1)))
	return;

	for (reg = 0; reg < 32; reg++)
	current->thread.fpu.fpr[reg] = *(ptr++);
	restore_fp(current);
	}

	/*
	* Similar to regs_to_gdb_regs() except that process is sleeping and so
	* we may not be able to get all the info.
	*/
	void sleeping_thread_to_gdb_regs(unsigned long gdb_regs, struct task_struct p)
	{
	int reg;
	struct thread_info *ti = task_thread_info(p);
	unsigned long ksp = (unsigned long)ti + THREAD_SIZE - 32;
	struct pt_regs regs = (struct pt_regs )ksp - 1;
	#if (KGDB_GDB_REG_SIZE == 32)
	u32 ptr = (u32 )gdb_regs;
	#else
	u64 ptr = (u64 )gdb_regs;
	#endif

	for (reg = 0; reg < 16; reg++)
	*(ptr++) = regs->regs[reg];

	/* S0 - S7 */
	for (reg = 16; reg < 24; reg++)
	*(ptr++) = regs->regs[reg];

	for (reg = 24; reg < 28; reg++)
	*(ptr++) = 0;

	/* GP, SP, FP, RA */
	for (reg = 28; reg < 32; reg++)
	*(ptr++) = regs->regs[reg];

	*(ptr++) = regs->cp0_status;
	*(ptr++) = regs->lo;
	*(ptr++) = regs->hi;
	*(ptr++) = regs->cp0_badvaddr;
	*(ptr++) = regs->cp0_cause;
	*(ptr++) = regs->cp0_epc;
	}

	void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long pc)
	{
	regs->cp0_epc = pc;
	}

	/*
	* Calls linux_debug_hook before the kernel dies. If KGDB is enabled,
	* then try to fall into the debugger
	*/
	static int kgdb_mips_notify(struct notifier_block *self, unsigned long cmd,
	void *ptr)
	{
	struct die_args args = (struct die_args )ptr;
	struct pt_regs *regs = args->regs;
	int trap = (regs->cp0_cause & 0x7c) >> 2;

	/* Userpace events, ignore. */
	if (user_mode(regs))
	return NOTIFY_DONE;

	if (atomic_read(&kgdb_active) != -1)
	kgdb_nmicallback(smp_processor_id(), regs);

	if (kgdb_handle_exception(trap, compute_signal(trap), cmd, regs))
	return NOTIFY_DONE;

	if (atomic_read(&kgdb_setting_breakpoint))
	if ((trap == 9) && (regs->cp0_epc == (unsigned long)breakinst))
	regs->cp0_epc += 4;

	/* In SMP mode, __flush_cache_all does IPI */
	local_irq_enable();
	__flush_cache_all();

	return NOTIFY_STOP;
	}

	#ifdef CONFIG_KGDB_LOW_LEVEL_TRAP
	int kgdb_ll_trap(int cmd, const char *str,
	struct pt_regs *regs, long err, int trap, int sig)
	{
	struct die_args args = {
	.regs = regs,
	.str = str,
	.err = err,
	.trapnr = trap,
	.signr = sig,

	};

	if (!kgdb_io_module_registered)
	return NOTIFY_DONE;

	return kgdb_mips_notify(NULL, cmd, &args);
	}
	#endif /* CONFIG_KGDB_LOW_LEVEL_TRAP */

	static struct notifier_block kgdb_notifier = {
	.notifier_call = kgdb_mips_notify,
	};

	/*
	* Handle the 's' and 'c' commands
	*/
	int kgdb_arch_handle_exception(int vector, int signo, int err_code,
	char remcom_in_buffer, char remcom_out_buffer,
	struct pt_regs *regs)
	{
	char *ptr;
	unsigned long address;
	int cpu = smp_processor_id();

	switch (remcom_in_buffer[0]) {
	case 's':
	case 'c':
	/* handle the optional parameter */
	ptr = &remcom_in_buffer[1];
	if (kgdb_hex2long(&ptr, &address))
	regs->cp0_epc = address;

	atomic_set(&kgdb_cpu_doing_single_step, -1);
	if (remcom_in_buffer[0] == 's')
	atomic_set(&kgdb_cpu_doing_single_step, cpu);

	return 0;
	}

	return -1;
	}

	struct kgdb_arch arch_kgdb_ops;

	/*
	* We use kgdb_early_setup so that functions we need to call now don't
	* cause trouble when called again later.
	*/
	int kgdb_arch_init(void)
	{
	union mips_instruction insn = {
	.r_format = {
	.opcode = spec_op,
	.func = break_op,
	}
	};
	memcpy(arch_kgdb_ops.gdb_bpt_instr, insn.byte, BREAK_INSTR_SIZE);

	register_die_notifier(&kgdb_notifier);

	return 0;
	}

	/*
	* kgdb_arch_exit - Perform any architecture specific uninitalization.
	*
	* This function will handle the uninitalization of any architecture
	* specific callbacks, for dynamic registration and unregistration.
	*/
	void kgdb_arch_exit(void)
	{
	unregister_die_notifier(&kgdb_notifier);
	}