KGDB set / remove breakpoints

index 0531452..66378e5 100644
@@ -220,6 +220,85 @@ hexToInt(char **ptr, int *intValue)
 	return (numChars);
 }
 
+/*
+ * Holds information about breakpoints in a kernel. These breakpoints are
+ * added and removed by gdb.
+ */
+static struct kgdb_bkpt	kgdb_break[KGDB_MAX_BREAKPOINTS];
+
+static int kgdb_set_sw_break(int addr)
+{
+	int i, breakno = -1;
+	struct kgdb_bkpt *bkpt;
+
+	for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
+		if ((kgdb_break[i].state == BP_SET) &&
+		    (kgdb_break[i].bpt_addr == addr))
+			return -KGDBERR_BPEXIST;
+		if ((kgdb_break[i].state == BP_REMOVED) &&
+		    (kgdb_break[i].bpt_addr == addr)) {
+			breakno = i;
+			break;
+		}
+	}
+	if (breakno == -1)
+		for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
+			if (kgdb_break[i].state == BP_UNDEFINED) {
+				breakno = i;
+				break;
+			}
+		}
+	if (breakno == -1)
+		return -KGDBERR_BPNOENT;
+
+	bkpt = kgdb_break + breakno;
+	bkpt->state = BP_SET;
+	bkpt->type = BP_BREAKPOINT;
+	bkpt->bpt_addr = addr;
+	arch_kgdb_set_sw_break(bkpt);
+
+	return 0;
+}
+
+static int kgdb_remove_sw_break(int addr)
+{
+	int i;
+	struct kgdb_bkpt *bkpt;
+
+	for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
+		bkpt = kgdb_break + i;
+		if ((bkpt->state == BP_SET) && (bkpt->bpt_addr == addr)) {
+			bkpt->state = BP_REMOVED;
+			arch_kgdb_remove_sw_break(bkpt);
+			return 0;
+		}
+	}
+	return -KGDBERR_BPNOENT;
+}
+
+/* Handle the 'z' or 'Z' breakpoint remove or set packets */
+static void gdb_cmd_break(kgdb_data *kdp)
+{
+	/*
+	 * Since GDB-5.3, it's been drafted that '0' is a software
+	 * breakpoint, '1' is a hardware breakpoint, so let's do that.
+	 */
+	char *bpt_type = &remcomInBuffer[1];
+	char *ptr = &remcomInBuffer[2];
+	int addr, length;
+
+	if (*bpt_type != '0')
+		return;		/* Unsupported. */
+	if (*ptr++ != ',' || !hexToInt(&ptr, &addr) ||
+	    *ptr++ != ',' || !hexToInt(&ptr, &length)) {
+		kgdb_error(KGDBERR_BADPARAMS);
+	}
+
+	if ((remcomInBuffer[0] == 'Z' && kgdb_set_sw_break(addr) == 0) ||
+	    (remcomInBuffer[0] == 'z' && kgdb_remove_sw_break(addr) == 0))
+		strcpy(remcomOutBuffer, "OK");
+}
+
 /* scan for the sequence $<data>#<checksum>     */
 static void
 getpacket(char *buffer)

@@ -341,7 +420,9 @@ handle_exception (struct pt_regs *regs)
 
 	kgdb_interruptible(0);
 
+#ifdef KGDB_DEBUG
 	printf("kgdb: handle_exception; trap [0x%x]\n", kgdb_trap(regs));
+#endif
 
 	if (kgdb_setjmp(error_jmp_buf) != 0)
 		panic("kgdb: error or fault in entry init!\n");

@@ -516,6 +597,10 @@ handle_exception (struct pt_regs *regs)
 				kgdb_error(KGDBERR_BADPARAMS);
 			}
 			break;
+		case 'Z': /* [Z|z]N,AA..AA,LLLL Set/Remove breakpoint type N */
+		case 'z': /*      LLLL bytes at address AA.AA return OK      */
+			gdb_cmd_break(&kd);
+			break;
 		}			/* switch */
 
 		if (errnum != 0)

index 19b0c18..2b3f424 100644
@@ -45,6 +45,18 @@ void kgdb_interruptible(int yes)
 }
 
 __attribute__((weak))
+void arch_kgdb_set_sw_break(struct kgdb_bkpt *bkpt)
+{
+	return;
+}
+
+__attribute__((weak))
+void arch_kgdb_remove_sw_break(struct kgdb_bkpt *bkpt)
+{
+	return;
+}
+
+__attribute__((weak))
 void kgdb_flush_cache_range(void *from, void *to)
 {
 	flush_cache((unsigned long)from, (unsigned long)(to - from));

index f543cd6..82ae8ab 100644
@@ -2,12 +2,41 @@
 #define __KGDB_H__
 
 #include <asm/ptrace.h>
+#include <asm/kgdb.h>
 
 #define KGDBERR_BADPARAMS	1
 #define KGDBERR_NOTHEXDIG	2
 #define KGDBERR_MEMFAULT	3
 #define KGDBERR_NOSPACE		4
 #define KGDBERR_ALIGNFAULT	5
+#define KGDBERR_BPEXIST		6
+#define KGDBERR_BPNOENT		7
+
+#ifndef KGDB_MAX_BREAKPOINTS
+#define KGDB_MAX_BREAKPOINTS	1000
+#endif
+
+enum kgdb_bptype {
+	BP_BREAKPOINT = 0,
+	BP_HARDWARE_BREAKPOINT,
+	BP_WRITE_WATCHPOINT,
+	BP_READ_WATCHPOINT,
+	BP_ACCESS_WATCHPOINT
+};
+
+enum kgdb_bpstate {
+	BP_UNDEFINED = 0,
+	BP_REMOVED,
+	BP_SET,
+	BP_ACTIVE
+};
+
+struct kgdb_bkpt {
+	unsigned long		bpt_addr;
+	unsigned char		saved_instr[BREAK_INSTR_SIZE];
+	enum kgdb_bptype	type;
+	enum kgdb_bpstate	state;
+};
 
 #define KGDBDATA_MAXREGS	8
 #define KGDBDATA_MAXPRIV	8

@@ -56,6 +85,8 @@ extern void kgdb_putreg(struct pt_regs *, int, char *, int);
 extern void kgdb_putregs(struct pt_regs *, char *, int);
 extern int kgdb_trap(struct pt_regs *);
 extern void kgdb_breakpoint(int argc, char *argv[]);
+extern void arch_kgdb_set_sw_break(struct kgdb_bkpt *);
+extern void arch_kgdb_remove_sw_break(struct kgdb_bkpt *);
 
 /* these functions are provided by the platform serial driver */
 extern void kgdb_serial_init(void);

index f5660a9..f2b028c 100644
@@ -381,6 +381,10 @@ void start_armboot (void)
 	/* miscellaneous platform dependent initialisations */
 	misc_init_r ();
 #endif
+#if defined(CONFIG_CMD_KGDB)
+	puts("KGDB:  ");
+	kgdb_init();
+#endif
 
 	/* enable exceptions */
 	enable_interrupts ();

index 1f2b815..6ee4309 100644
@@ -37,6 +37,9 @@
 
 #include <common.h>
 #include <asm/proc-armv/ptrace.h>
+#ifdef CONFIG_CMD_KGDB
+#include <kgdb.h>
+#endif
 
 #ifdef CONFIG_USE_IRQ
 DECLARE_GLOBAL_DATA_PTR;

@@ -137,6 +140,12 @@ void show_regs (struct pt_regs *regs)
 
 void do_undefined_instruction (struct pt_regs *pt_regs)
 {
+#ifdef CONFIG_CMD_KGDB
+	if (*(unsigned long *)(instruction_pointer(pt_regs) - 4) == KGDB_COMPILED_BREAK) {
+		(*debugger_exception_handler)(pt_regs);
+		return;
+	}
+#endif
 	printf ("undefined instruction\n");
 	show_regs (pt_regs);
 	bad_mode ();

new file mode 100644
index 0000000..dfca31c
@@ -0,0 +1,66 @@
+/*
+ * ARM KGDB support
+ *
+ * Author: Deepak Saxena <[email protected]>
+ *
+ * Copyright (C) 2002 MontaVista Software Inc.
+ *
+ */
+#ifndef __ARM_KGDB_H__
+#define __ARM_KGDB_H__
+
+#define BREAK_INSTR_SIZE	4
+#define KGDB_COMPILED_BREAK	0xe7ffdeff
+
+#ifndef	__ASSEMBLY__
+
+static inline void arch_kgdb_breakpoint(void)
+{
+	asm(".word 0xe7ffdeff");
+}
+
+#endif /* !__ASSEMBLY__ */
+
+/*
+ * From Kevin Hilman:
+ *
+ * gdb is expecting the following registers layout.
+ *
+ * r0-r15: 1 long word each
+ * f0-f7:  unused, 3 long words each !!
+ * fps:    unused, 1 long word
+ * cpsr:   1 long word
+ *
+ * Even though f0-f7 and fps are not used, they need to be
+ * present in the registers sent for correct processing in
+ * the host-side gdb.
+ *
+ * In particular, it is crucial that CPSR is in the right place,
+ * otherwise gdb will not be able to correctly interpret stepping over
+ * conditional branches.
+ */
+#define _GP_REGS		16
+#define _FP_REGS		8
+#define _EXTRA_REGS		2
+#define GDB_MAX_REGS		(_GP_REGS + (_FP_REGS * 3) + _EXTRA_REGS)
+
+#define _R0			0
+#define _R1			1
+#define _R2			2
+#define _R3			3
+#define _R4			4
+#define _R5			5
+#define _R6			6
+#define _R7			7
+#define _R8			8
+#define _R9			9
+#define _R10			10
+#define _FP			11
+#define _IP			12
+#define _SPT			13
+#define _LR			14
+#define _PC			15
+#define _CPSR			(GDB_MAX_REGS - 1)
+
+#endif /* __ASM_KGDB_H__ */
+

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