MN10300: Use KGDB

arch/mn10300/Kconfig

@@ -3,6 +3,8 @@ config MN10300
 	select HAVE_OPROFILE
 	select HAVE_GENERIC_HARDIRQS
 	select GENERIC_HARDIRQS_NO_DEPRECATED
+	select HAVE_ARCH_TRACEHOOK
+	select HAVE_ARCH_KGDB
 
 config AM33_2
 	def_bool n

arch/mn10300/Kconfig.debug

@@ -153,4 +153,4 @@ endmenu
 
 config KERNEL_DEBUGGER
 	def_bool y
-	depends on GDBSTUB
+	depends on GDBSTUB || KGDB

arch/mn10300/include/asm/kgdb.h

@@ -0,0 +1,81 @@
+/* Kernel debugger for MN10300
+ *
+ * Copyright (C) 2010 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public Licence
+ * as published by the Free Software Foundation; either version
+ * 2 of the Licence, or (at your option) any later version.
+ */
+
+#ifndef _ASM_KGDB_H
+#define _ASM_KGDB_H
+
+/*
+ * BUFMAX defines the maximum number of characters in inbound/outbound
+ * buffers at least NUMREGBYTES*2 are needed for register packets
+ * Longer buffer is needed to list all threads
+ */
+#define BUFMAX			1024
+
+/*
+ * Note that this register image is in a different order than the register
+ * image that Linux produces at interrupt time.
+ */
+enum regnames {
+	GDB_FR_D0		= 0,
+	GDB_FR_D1		= 1,
+	GDB_FR_D2		= 2,
+	GDB_FR_D3		= 3,
+	GDB_FR_A0		= 4,
+	GDB_FR_A1		= 5,
+	GDB_FR_A2		= 6,
+	GDB_FR_A3		= 7,
+
+	GDB_FR_SP		= 8,
+	GDB_FR_PC		= 9,
+	GDB_FR_MDR		= 10,
+	GDB_FR_EPSW		= 11,
+	GDB_FR_LIR		= 12,
+	GDB_FR_LAR		= 13,
+	GDB_FR_MDRQ		= 14,
+
+	GDB_FR_E0		= 15,
+	GDB_FR_E1		= 16,
+	GDB_FR_E2		= 17,
+	GDB_FR_E3		= 18,
+	GDB_FR_E4		= 19,
+	GDB_FR_E5		= 20,
+	GDB_FR_E6		= 21,
+	GDB_FR_E7		= 22,
+
+	GDB_FR_SSP		= 23,
+	GDB_FR_MSP		= 24,
+	GDB_FR_USP		= 25,
+	GDB_FR_MCRH		= 26,
+	GDB_FR_MCRL		= 27,
+	GDB_FR_MCVF		= 28,
+
+	GDB_FR_FPCR		= 29,
+	GDB_FR_DUMMY0		= 30,
+	GDB_FR_DUMMY1		= 31,
+
+	GDB_FR_FS0		= 32,
+
+	GDB_FR_SIZE		= 64,
+};
+
+#define GDB_ORIG_D0		41
+#define NUMREGBYTES		(GDB_FR_SIZE*4)
+
+static inline void arch_kgdb_breakpoint(void)
+{
+	asm(".globl __arch_kgdb_breakpoint; __arch_kgdb_breakpoint: break");
+}
+extern u8 __arch_kgdb_breakpoint;
+
+#define BREAK_INSTR_SIZE	1
+#define CACHE_FLUSH_IS_SAFE	1
+
+#endif /* _ASM_KGDB_H */

arch/mn10300/include/asm/smp.h

@@ -62,8 +62,9 @@
  * An alternate way of dealing with this could be to use the EPSW.S bits to
  * cache this information for systems with up to four CPUs.
  */
+#define arch_smp_processor_id()	(CPUID)
 #if 0
-#define raw_smp_processor_id()	(CPUID)
+#define raw_smp_processor_id()	(arch_smp_processor_id())
 #else
 #define raw_smp_processor_id()	(current_thread_info()->cpu)
 #endif

arch/mn10300/kernel/Makefile

@@ -25,3 +25,4 @@ obj-$(CONFIG_MN10300_RTC) += rtc.o
 obj-$(CONFIG_PROFILE) += profile.o profile-low.o
 obj-$(CONFIG_MODULES) += module.o
 obj-$(CONFIG_KPROBES) += kprobes.o
+obj-$(CONFIG_KGDB) += kgdb.o

arch/mn10300/kernel/kgdb.c

@@ -0,0 +1,202 @@
+/* kgdb support for MN10300
+ *
+ * Copyright (C) 2010 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public Licence
+ * as published by the Free Software Foundation; either version
+ * 2 of the Licence, or (at your option) any later version.
+ */
+
+#include <linux/ptrace.h>
+#include <linux/kgdb.h>
+#include <linux/uaccess.h>
+#include <unit/leds.h>
+#include <unit/serial.h>
+#include <asm/debugger.h>
+#include <asm/serial-regs.h>
+#include "internal.h"
+
+/*
+ * Copy kernel exception frame registers to the GDB register file
+ */
+void pt_regs_to_gdb_regs(unsigned long *gdb_regs, struct pt_regs *regs)
+{
+	unsigned long ssp = (unsigned long) (regs + 1);
+
+	gdb_regs[GDB_FR_D0]	= regs->d0;
+	gdb_regs[GDB_FR_D1]	= regs->d1;
+	gdb_regs[GDB_FR_D2]	= regs->d2;
+	gdb_regs[GDB_FR_D3]	= regs->d3;
+	gdb_regs[GDB_FR_A0]	= regs->a0;
+	gdb_regs[GDB_FR_A1]	= regs->a1;
+	gdb_regs[GDB_FR_A2]	= regs->a2;
+	gdb_regs[GDB_FR_A3]	= regs->a3;
+	gdb_regs[GDB_FR_SP]	= (regs->epsw & EPSW_nSL) ? regs->sp : ssp;
+	gdb_regs[GDB_FR_PC]	= regs->pc;
+	gdb_regs[GDB_FR_MDR]	= regs->mdr;
+	gdb_regs[GDB_FR_EPSW]	= regs->epsw;
+	gdb_regs[GDB_FR_LIR]	= regs->lir;
+	gdb_regs[GDB_FR_LAR]	= regs->lar;
+	gdb_regs[GDB_FR_MDRQ]	= regs->mdrq;
+	gdb_regs[GDB_FR_E0]	= regs->e0;
+	gdb_regs[GDB_FR_E1]	= regs->e1;
+	gdb_regs[GDB_FR_E2]	= regs->e2;
+	gdb_regs[GDB_FR_E3]	= regs->e3;
+	gdb_regs[GDB_FR_E4]	= regs->e4;
+	gdb_regs[GDB_FR_E5]	= regs->e5;
+	gdb_regs[GDB_FR_E6]	= regs->e6;
+	gdb_regs[GDB_FR_E7]	= regs->e7;
+	gdb_regs[GDB_FR_SSP]	= ssp;
+	gdb_regs[GDB_FR_MSP]	= 0;
+	gdb_regs[GDB_FR_USP]	= regs->sp;
+	gdb_regs[GDB_FR_MCRH]	= regs->mcrh;
+	gdb_regs[GDB_FR_MCRL]	= regs->mcrl;
+	gdb_regs[GDB_FR_MCVF]	= regs->mcvf;
+	gdb_regs[GDB_FR_DUMMY0]	= 0;
+	gdb_regs[GDB_FR_DUMMY1]	= 0;
+	gdb_regs[GDB_FR_FS0]	= 0;
+}
+
+/*
+ * Extracts kernel SP/PC values understandable by gdb from the values
+ * saved by switch_to().
+ */
+void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *p)
+{
+	gdb_regs[GDB_FR_SSP]	= p->thread.sp;
+	gdb_regs[GDB_FR_PC]	= p->thread.pc;
+	gdb_regs[GDB_FR_A3]	= p->thread.a3;
+	gdb_regs[GDB_FR_USP]	= p->thread.usp;
+	gdb_regs[GDB_FR_FPCR]	= p->thread.fpu_state.fpcr;
+}
+
+/*
+ * Fill kernel exception frame registers from the GDB register file
+ */
+void gdb_regs_to_pt_regs(unsigned long *gdb_regs, struct pt_regs *regs)
+{
+	regs->d0	= gdb_regs[GDB_FR_D0];
+	regs->d1	= gdb_regs[GDB_FR_D1];
+	regs->d2	= gdb_regs[GDB_FR_D2];
+	regs->d3	= gdb_regs[GDB_FR_D3];
+	regs->a0	= gdb_regs[GDB_FR_A0];
+	regs->a1	= gdb_regs[GDB_FR_A1];
+	regs->a2	= gdb_regs[GDB_FR_A2];
+	regs->a3	= gdb_regs[GDB_FR_A3];
+	regs->sp	= gdb_regs[GDB_FR_SP];
+	regs->pc	= gdb_regs[GDB_FR_PC];
+	regs->mdr	= gdb_regs[GDB_FR_MDR];
+	regs->epsw	= gdb_regs[GDB_FR_EPSW];
+	regs->lir	= gdb_regs[GDB_FR_LIR];
+	regs->lar	= gdb_regs[GDB_FR_LAR];
+	regs->mdrq	= gdb_regs[GDB_FR_MDRQ];
+	regs->e0	= gdb_regs[GDB_FR_E0];
+	regs->e1	= gdb_regs[GDB_FR_E1];
+	regs->e2	= gdb_regs[GDB_FR_E2];
+	regs->e3	= gdb_regs[GDB_FR_E3];
+	regs->e4	= gdb_regs[GDB_FR_E4];
+	regs->e5	= gdb_regs[GDB_FR_E5];
+	regs->e6	= gdb_regs[GDB_FR_E6];
+	regs->e7	= gdb_regs[GDB_FR_E7];
+	regs->sp	= gdb_regs[GDB_FR_SSP];
+	/* gdb_regs[GDB_FR_MSP]; */
+	// regs->usp	= gdb_regs[GDB_FR_USP];
+	regs->mcrh	= gdb_regs[GDB_FR_MCRH];
+	regs->mcrl	= gdb_regs[GDB_FR_MCRL];
+	regs->mcvf	= gdb_regs[GDB_FR_MCVF];
+	/* gdb_regs[GDB_FR_DUMMY0]; */
+	/* gdb_regs[GDB_FR_DUMMY1]; */
+
+	// regs->fpcr	= gdb_regs[GDB_FR_FPCR];
+	// regs->fs0	= gdb_regs[GDB_FR_FS0];
+}
+
+struct kgdb_arch arch_kgdb_ops = {
+	.gdb_bpt_instr	= { 0xff },
+	.flags		= KGDB_HW_BREAKPOINT,
+};
+
+/*
+ * Handle unknown packets and [Ccs] packets
+ */
+int kgdb_arch_handle_exception(int vector, int signo, int err_code,
+			       char *remcom_in_buffer, char *remcom_out_buffer,
+			       struct pt_regs *regs)
+{
+	long addr;
+	char *ptr;
+
+	switch (remcom_in_buffer[0]) {
+	case 'c':
+		if (kgdb_contthread && kgdb_contthread != current) {
+			strcpy(remcom_out_buffer, "E00");
+			break;
+		}
+
+		kgdb_contthread = NULL;
+
+		/* try to read optional parameter, pc unchanged if no parm */
+		ptr = &remcom_in_buffer[1];
+		if (kgdb_hex2long(&ptr, &addr))
+			regs->pc = addr;
+		return 0;
+
+	case 's':
+		break; /* we don't do hardware single stepping */
+	}
+	return -1; /* this means that we do not want to exit from the handler */
+}
+
+/*
+ * Handle event interception
+ * - returns 0 if the exception should be skipped, -ERROR otherwise.
+ */
+int debugger_intercept(enum exception_code excep, int signo, int si_code,
+		       struct pt_regs *regs)
+{
+	int ret;
+
+	ret = kgdb_handle_exception(excep, signo, si_code, regs);
+
+	debugger_local_cache_flushinv();
+
+	return ret;
+}
+
+/*
+ * Determine if we've hit a debugger special breakpoint
+ */
+int at_debugger_breakpoint(struct pt_regs *regs)
+{
+	return regs->pc == (unsigned long)&__arch_kgdb_breakpoint;
+}
+
+/*
+ * Initialise kgdb
+ */
+int kgdb_arch_init(void)
+{
+	return 0;
+}
+
+/*
+ * Do something, perhaps, but don't know what.
+ */
+void kgdb_arch_exit(void)
+{
+}
+
+#ifdef CONFIG_SMP
+void debugger_nmi_interrupt(struct pt_regs *regs, enum exception_code code)
+{
+	kgdb_nmicallback(arch_smp_processor_id(), regs);
+	debugger_local_cache_flushinv();
+}
+
+void kgdb_roundup_cpus(unsigned long flags)
+{
+	smp_jump_to_debugger();
+}
+#endif