Mega update for the KDB framework: turn DDB into a KDB backend.

Most of the changes are a direct result of adding thread awareness.
Typically, DDB_REGS is gone. All registers are taken from the
trapframe and backtraces use the PCB based contexts. DDB_REGS was
defined to be a trapframe on all platforms anyway.
Thread awareness introduces the following new commands:
	thread X	switch to thread X (where X is the TID),
	show threads	list all threads.

The backtrace code has been made more flexible so that one can
create backtraces for any thread by giving the thread ID as an
argument to trace.

With this change, ia64 has support for breakpoints.

1 files changed, 226 insertions, 0 deletions

diff --git a/sys/ddb/db_main.c b/sys/ddb/db_main.c
new file mode 100644
index 0000000..32dd347
--- /dev/null
+++ b/sys/ddb/db_main.c
@@ -0,0 +1,226 @@
+/*
+ * Mach Operating System
+ * Copyright (c) 1991,1990 Carnegie Mellon University
+ * All Rights Reserved.
+ *
+ * Permission to use, copy, modify and distribute this software and its
+ * documentation is hereby granted, provided that both the copyright
+ * notice and this permission notice appear in all copies of the
+ * software, derivative works or modified versions, and any portions
+ * thereof, and that both notices appear in supporting documentation.
+ *
+ * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS
+ * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
+ * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
+ *
+ * Carnegie Mellon requests users of this software to return to
+ *
+ *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
+ *  School of Computer Science
+ *  Carnegie Mellon University
+ *  Pittsburgh PA 15213-3890
+ *
+ * any improvements or extensions that they make and grant Carnegie the
+ * rights to redistribute these changes.
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/cons.h>
+#include <sys/linker.h>
+#include <sys/kdb.h>
+#include <sys/kernel.h>
+#include <sys/pcpu.h>
+#include <sys/proc.h>
+#include <sys/reboot.h>
+
+#include <machine/kdb.h>
+#include <machine/pcb.h>
+#include <machine/setjmp.h>
+
+#include <ddb/ddb.h>
+#include <ddb/db_command.h>
+#include <ddb/db_sym.h>
+
+static dbbe_init_f db_init;
+static dbbe_trap_f db_trap;
+
+KDB_BACKEND(ddb, db_init, db_trace_self, db_trap);
+
+vm_offset_t ksym_start, ksym_end;
+
+boolean_t
+X_db_line_at_pc(db_symtab_t *symtab, c_db_sym_t sym, char **file, int *line,
+    db_expr_t off)
+{
+	return (FALSE);
+}
+
+c_db_sym_t
+X_db_lookup(db_symtab_t *symtab, const char *symbol)
+{
+	c_linker_sym_t lsym;
+	Elf_Sym *sym;
+
+	if (symtab->private == NULL) {
+		return ((c_db_sym_t)((!linker_ddb_lookup(symbol, &lsym))
+			? lsym : NULL));
+	} else {
+		sym = (Elf_Sym *)symtab->start;
+		while ((char *)sym < symtab->end) {
+			if (sym->st_name != 0 &&
+			    !strcmp(symtab->private + sym->st_name, symbol))
+				return ((c_db_sym_t)sym);
+			sym++;
+		}
+	}
+	return (NULL);
+}
+
+c_db_sym_t
+X_db_search_symbol(db_symtab_t *symtab, db_addr_t off, db_strategy_t strat,
+    db_expr_t *diffp)
+{
+	c_linker_sym_t lsym;
+	Elf_Sym *sym, *match;
+	unsigned long diff;
+
+	if (symtab->private == NULL) {
+		if (!linker_ddb_search_symbol((caddr_t)off, &lsym, &diff)) {
+			*diffp = (db_expr_t)diff;
+			return ((c_db_sym_t)lsym);
+		}
+		return (NULL);
+	}
+
+	diff = ~0UL;
+	match = NULL;
+	for (sym = (Elf_Sym*)symtab->start; (char*)sym < symtab->end; sym++) {
+		if (sym->st_name == 0)
+			continue;
+		if (off < sym->st_value)
+			continue;
+		if (ELF_ST_TYPE(sym->st_info) != STT_OBJECT &&
+		    ELF_ST_TYPE(sym->st_info) != STT_FUNC &&
+		    ELF_ST_TYPE(sym->st_info) != STT_NOTYPE)
+			continue;
+		if ((off - sym->st_value) > diff)
+			continue;
+		if ((off - sym->st_value) < diff) {
+			diff = off - sym->st_value;
+			match = sym;
+		} else {
+			if (match == NULL)
+				match = sym;
+			else if (ELF_ST_BIND(match->st_info) == STB_LOCAL &&
+			    ELF_ST_BIND(sym->st_info) != STB_LOCAL)
+				match = sym;
+		}
+		if (diff == 0) {
+			if (strat == DB_STGY_PROC &&
+			    ELF_ST_TYPE(sym->st_info) == STT_FUNC &&
+			    ELF_ST_BIND(sym->st_info) != STB_LOCAL)
+				break;
+			if (strat == DB_STGY_ANY &&
+			    ELF_ST_BIND(sym->st_info) != STB_LOCAL)
+				break;
+		}
+	}
+
+	*diffp = (match == NULL) ? off : diff;
+	return ((c_db_sym_t)match);
+}
+
+boolean_t
+X_db_sym_numargs(db_symtab_t *symtab, c_db_sym_t sym, int *nargp,
+    char **argp)
+{
+	return (FALSE);
+}
+
+void
+X_db_symbol_values(db_symtab_t *symtab, c_db_sym_t sym, const char **namep,
+    db_expr_t *valp)
+{
+	linker_symval_t lval;
+
+	if (symtab->private == NULL) {
+		linker_ddb_symbol_values((c_linker_sym_t)sym, &lval);
+		if (namep != NULL)
+			*namep = (const char*)lval.name;
+		if (valp != NULL)
+			*valp = (db_expr_t)lval.value;
+	} else {
+		if (namep != NULL)
+			*namep = (const char *)symtab->private +
+			    ((const Elf_Sym *)sym)->st_name;
+		if (valp != NULL)
+			*valp = (db_expr_t)((const Elf_Sym *)sym)->st_value;
+	}
+}
+
+static int
+db_init(void)
+{
+	uintptr_t symtab, strtab;
+	Elf_Size tabsz, strsz;
+
+	if (ksym_end > ksym_start && ksym_start != 0) {
+		symtab = ksym_start;
+		tabsz = *((Elf_Size*)symtab)++;
+		strtab = symtab + tabsz;
+		strsz = *((Elf_Size*)strtab)++;
+		if (strtab + strsz <= ksym_end) {
+			db_add_symbol_table((char *)symtab,
+			    (char *)(symtab + tabsz), "elf", (char *)strtab);
+		}
+	}
+	db_add_symbol_table(NULL, NULL, "kld", NULL);
+	return (1);	/* We're the default debugger. */
+}
+
+static int
+db_trap(int type, int code)
+{
+	jmp_buf jb;
+	void *prev_jb;
+	boolean_t bkpt, watchpt;
+
+	/*
+	 * Don't handle the trap if the console is unavailable (i.e. it
+	 * is in graphics mode).
+	 */
+	if (cnunavailable())
+		return (0);
+
+	bkpt = IS_BREAKPOINT_TRAP(type, code);
+	watchpt = IS_WATCHPOINT_TRAP(type, code);
+
+	if (db_stop_at_pc(&bkpt)) {
+		if (db_inst_count) {
+			db_printf("After %d instructions (%d loads, %d stores),\n",
+			    db_inst_count, db_load_count, db_store_count);
+		}
+		prev_jb = kdb_jmpbuf(jb);
+		if (setjmp(jb) == 0) {
+			db_dot = PC_REGS();
+			db_print_thread();
+			if (bkpt)
+				db_printf("Breakpoint at\t");
+			else if (watchpt)
+				db_printf("Watchpoint at\t");
+			else
+				db_printf("Stopped at\t");
+			db_print_loc_and_inst(db_dot);
+		}
+		db_command_loop();
+		(void)kdb_jmpbuf(prev_jb);
+	}
+
+	db_restart_at_pc(watchpt);
+
+	return (1);
+}