sh: Generic kgdb stub support.

This migrates from the old bitrotted kgdb stub implementation and moves
to the generic stub. In the process support for SH-2/SH-2A is also added,
which the old stub never provided.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>

arch/sh/Kconfig

@@ -27,6 +27,7 @@ config SUPERH32
 	select HAVE_FUNCTION_TRACER
 	select HAVE_FTRACE_MCOUNT_RECORD
 	select HAVE_DYNAMIC_FTRACE
+	select HAVE_ARCH_KGDB
 
 config SUPERH64
 	def_bool y if CPU_SH5

arch/sh/Kconfig.debug

@@ -98,19 +98,6 @@ config IRQSTACKS
 	  for handling hard and soft interrupts.  This can help avoid
 	  overflowing the process kernel stacks.
 
-config SH_KGDB
-	bool "Include KGDB kernel debugger"
-	select FRAME_POINTER
-	select DEBUG_INFO
-	depends on CPU_SH3 || CPU_SH4
-	help
-	  Include in-kernel hooks for kgdb, the Linux kernel source level
-	  debugger.  See <http://kgdb.sourceforge.net/> for more information.
-	  Unless you are intending to debug the kernel, say N here.
-
-menu "KGDB configuration options"
-	depends on SH_KGDB
-
 config MORE_COMPILE_OPTIONS
 	bool "Add any additional compile options"
 	help
@@ -122,62 +109,6 @@ config COMPILE_OPTIONS
 	string "Additional compile arguments"
 	depends on MORE_COMPILE_OPTIONS
 
-config KGDB_NMI
-	def_bool n
-	prompt "Enter KGDB on NMI"
-
-config SH_KGDB_CONSOLE
-	def_bool n
-	prompt "Console messages through GDB"
-	depends on !SERIAL_SH_SCI_CONSOLE && SERIAL_SH_SCI=y
-	select SERIAL_CORE_CONSOLE
-
-config KGDB_SYSRQ
-	def_bool y
-	prompt "Allow SysRq 'G' to enter KGDB"
-	depends on MAGIC_SYSRQ
-
-comment "Serial port setup"
-
-config KGDB_DEFPORT
-	int "Port number (ttySCn)"
-	default "1"
-
-config KGDB_DEFBAUD
-	int "Baud rate"
-	default "115200"
-
-choice
-	prompt "Parity"
-	depends on SH_KGDB
-	default KGDB_DEFPARITY_N
-
-config KGDB_DEFPARITY_N
-	bool "None"
-
-config KGDB_DEFPARITY_E
-	bool "Even"
-
-config KGDB_DEFPARITY_O
-	bool "Odd"
-
-endchoice
-
-choice
-	prompt "Data bits"
-	depends on SH_KGDB
-	default KGDB_DEFBITS_8
-
-config KGDB_DEFBITS_8
-	bool "8"
-
-config KGDB_DEFBITS_7
-	bool "7"
-
-endchoice
-
-endmenu
-
 if SUPERH64
 
 config SH64_SR_WATCH

arch/sh/include/asm/kgdb.h

@@ -1,21 +1,7 @@
-/*
- * May be copied or modified under the terms of the GNU General Public
- * License.  See linux/COPYING for more information.
- *
- * Based on original code by Glenn Engel, Jim Kingdon,
- * David Grothe <dave@gcom.com>, Tigran Aivazian, <tigran@sco.com> and
- * Amit S. Kale <akale@veritas.com>
- * 
- * Super-H port based on sh-stub.c (Ben Lee and Steve Chamberlain) by
- * Henry Bell <henry.bell@st.com>
- * 
- * Header file for low-level support for remote debug using GDB. 
- *
- */
-
-#ifndef __KGDB_H
-#define __KGDB_H
+#ifndef __ASM_SH_KGDB_H
+#define __ASM_SH_KGDB_H
 
+#include <asm/cacheflush.h>
 #include <asm/ptrace.h>
 
 /* Same as pt_regs but has vbr in place of syscall_nr */
@@ -30,40 +16,26 @@ struct kgdb_regs {
         unsigned long vbr;
 };
 
-/* State info */
-extern char kgdb_in_gdb_mode;
-extern int kgdb_nofault;	/* Ignore bus errors (in gdb mem access) */
-extern char in_nmi;		/* Debounce flag to prevent NMI reentry*/
+enum regnames {
+	GDB_R0, GDB_R1, GDB_R2, GDB_R3, GDB_R4, GDB_R5, GDB_R6, GDB_R7,
+	GDB_R8, GDB_R9, GDB_R10, GDB_R11, GDB_R12, GDB_R13, GDB_R14, GDB_R15,
 
-/* SCI */
-extern int kgdb_portnum;
-extern int kgdb_baud;
-extern char kgdb_parity;
-extern char kgdb_bits;
+	GDB_PC, GDB_PR, GDB_SR, GDB_GBR, GDB_MACH, GDB_MACL, GDB_VBR,
+};
 
-/* Init and interface stuff */
-extern int kgdb_init(void);
-extern int (*kgdb_getchar)(void);
-extern void (*kgdb_putchar)(int);
+#define NUMREGBYTES    ((GDB_VBR + 1) * 4)
 
-/* Trap functions */
-typedef void (kgdb_debug_hook_t)(struct pt_regs *regs);
-typedef void (kgdb_bus_error_hook_t)(void);
-extern kgdb_debug_hook_t  *kgdb_debug_hook;
-extern kgdb_bus_error_hook_t *kgdb_bus_err_hook;
+static inline void arch_kgdb_breakpoint(void)
+{
+	__asm__ __volatile__ ("trapa #0x3c\n");
+}
 
-/* Console */
-struct console;
-void kgdb_console_write(struct console *co, const char *s, unsigned count);
-extern int kgdb_console_setup(struct console *, char *);
+/* State info */
+extern char in_nmi;		/* Debounce flag to prevent NMI reentry*/
 
-/* Prototypes for jmp fns */
-#define _JBLEN 9
-typedef        int jmp_buf[_JBLEN];
-extern void    longjmp(jmp_buf __jmpb, int __retval);
-extern int     setjmp(jmp_buf __jmpb);
+#define BUFMAX                 2048
 
-/* Forced breakpoint */
-#define breakpoint()	__asm__ __volatile__("trapa   #0x3c")
+#define CACHE_FLUSH_IS_SAFE	1
+#define BREAK_INSTR_SIZE	2
 
-#endif
+#endif /* __ASM_SH_KGDB_H */

arch/sh/include/asm/system.h

@@ -175,6 +175,8 @@ asmlinkage void name##_trap_handler(unsigned int vec, struct pt_regs *regs)
 BUILD_TRAP_HANDLER(address_error);
 BUILD_TRAP_HANDLER(debug);
 BUILD_TRAP_HANDLER(bug);
+BUILD_TRAP_HANDLER(breakpoint);
+BUILD_TRAP_HANDLER(singlestep);
 BUILD_TRAP_HANDLER(fpu_error);
 BUILD_TRAP_HANDLER(fpu_state_restore);
 

arch/sh/kernel/Makefile_32

@@ -19,7 +19,7 @@ obj-$(CONFIG_VSYSCALL)		+= vsyscall/
 obj-$(CONFIG_SMP)		+= smp.o
 obj-$(CONFIG_CF_ENABLER)	+= cf-enabler.o
 obj-$(CONFIG_SH_STANDARD_BIOS)	+= sh_bios.o
-obj-$(CONFIG_SH_KGDB)		+= kgdb_stub.o kgdb_jmp.o
+obj-$(CONFIG_KGDB)		+= kgdb.o
 obj-$(CONFIG_SH_CPU_FREQ)	+= cpufreq.o
 obj-$(CONFIG_MODULES)		+= sh_ksyms_32.o module.o
 obj-$(CONFIG_EARLY_PRINTK)	+= early_printk.o

arch/sh/kernel/cpu/sh3/entry.S

@@ -52,7 +52,7 @@
  *	syscall #
  *
  */
-#if defined(CONFIG_KGDB_NMI)
+#if defined(CONFIG_KGDB)
 NMI_VEC = 0x1c0			! Must catch early for debounce
 #endif
 
@@ -307,7 +307,7 @@ skip_restore:
 6:	or	k0, k2			! Set the IMASK-bits
 	ldc	k2, ssr
 	!
-#if defined(CONFIG_KGDB_NMI)
+#if defined(CONFIG_KGDB)
 	! Clear in_nmi
 	mov.l	6f, k0
 	mov	#0, k1
@@ -320,7 +320,7 @@ skip_restore:
 
 	.align	2
 5:	.long	0x00001000	! DSP
-#ifdef CONFIG_KGDB_NMI
+#ifdef CONFIG_KGDB
 6:	.long	in_nmi
 #endif
 7:	.long	0x30000000
@@ -377,7 +377,7 @@ tlb_miss:
 	.balign 	512,0,512
 interrupt:
 	mov.l	3f, k3
-#if defined(CONFIG_KGDB_NMI)
+#if defined(CONFIG_KGDB)
 	mov.l	2f, k2
 	! Debounce (filter nested NMI)
 	mov.l	@k2, k0
@@ -394,7 +394,7 @@ interrupt:
 5:	.long	NMI_VEC
 6:	.long	in_nmi
 0:
-#endif /* defined(CONFIG_KGDB_NMI) */
+#endif /* defined(CONFIG_KGDB) */
 	bra	handle_exception
 	 mov	#-1, k2		! interrupt exception marker
 

arch/sh/kernel/cpu/sh3/ex.S

@@ -26,7 +26,7 @@
 #define	fpu_error_trap_handler		exception_error
 #endif
 
-#if !defined(CONFIG_KGDB_NMI)
+#if !defined(CONFIG_KGDB)
 #define kgdb_handle_exception		exception_error
 #endif
 

arch/sh/kernel/debugtraps.S

@@ -3,7 +3,7 @@
  *
  * Debug trap jump tables for SuperH
  *
- *  Copyright (C) 2006  Paul Mundt
+ *  Copyright (C) 2006 - 2008  Paul Mundt
  *
  * This file is subject to the terms and conditions of the GNU General Public
  * License.  See the file "COPYING" in the main directory of this archive
@@ -12,12 +12,13 @@
 #include <linux/sys.h>
 #include <linux/linkage.h>
 
-#if !defined(CONFIG_SH_KGDB)
-#define kgdb_handle_exception	debug_trap_handler
+#if !defined(CONFIG_KGDB)
+#define breakpoint_trap_handler		debug_trap_handler
+#define singlestep_trap_handler		debug_trap_handler
 #endif
 
 #if !defined(CONFIG_SH_STANDARD_BIOS)
-#define sh_bios_handler		debug_trap_handler
+#define sh_bios_handler			debug_trap_handler
 #endif
 
 	.data
@@ -35,7 +36,7 @@ ENTRY(debug_trap_table)
 	.long debug_trap_handler	/* 0x39 */
 	.long debug_trap_handler	/* 0x3a */
 	.long debug_trap_handler	/* 0x3b */
-	.long kgdb_handle_exception	/* 0x3c */
-	.long debug_trap_handler	/* 0x3d */
+	.long breakpoint_trap_handler	/* 0x3c */
+	.long singlestep_trap_handler	/* 0x3d */
 	.long bug_trap_handler		/* 0x3e */
 	.long sh_bios_handler		/* 0x3f */

arch/sh/kernel/entry-common.S

@@ -308,15 +308,19 @@ ENTRY(system_call)
 	mov.l	1f, r9
 	mov.l	@r9, r8		! Read from TRA (Trap Address) Register
 #endif
+
+	mov	#OFF_TRA, r10
+	add	r15, r10
+	mov.l	r8, @r10		! set TRA value to tra
+
 	/*
 	 * Check the trap type
 	 */
 	mov	#((0x20 << 2) - 1), r9
 	cmp/hi	r9, r8
 	bt/s	debug_trap		! it's a debug trap..
-	 mov	#OFF_TRA, r9
-	add	r15, r9
-	mov.l	r8, @r9			! set TRA value to tra
+	 nop
+
 #ifdef CONFIG_TRACE_IRQFLAGS
 	mov.l	5f, r10
 	jsr	@r10