db_main.c revision 139747 
1/*-
2 * Mach Operating System
3 * Copyright (c) 1991,1990 Carnegie Mellon University
4 * All Rights Reserved.
5 *
6 * Permission to use, copy, modify and distribute this software and its
7 * documentation is hereby granted, provided that both the copyright
8 * notice and this permission notice appear in all copies of the
9 * software, derivative works or modified versions, and any portions
10 * thereof, and that both notices appear in supporting documentation.
11 *
12 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS
13 * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
14 * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
15 *
16 * Carnegie Mellon requests users of this software to return to
17 *
18 *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
19 *  School of Computer Science
20 *  Carnegie Mellon University
21 *  Pittsburgh PA 15213-3890
22 *
23 * any improvements or extensions that they make and grant Carnegie the
24 * rights to redistribute these changes.
25 */
26
27#include <sys/cdefs.h>
28__FBSDID("$FreeBSD: head/sys/ddb/db_main.c 139747 2005-01-06 01:34:41Z imp $");
29
30#include <sys/param.h>
31#include <sys/systm.h>
32#include <sys/cons.h>
33#include <sys/linker.h>
34#include <sys/kdb.h>
35#include <sys/kernel.h>
36#include <sys/pcpu.h>
37#include <sys/proc.h>
38#include <sys/reboot.h>
39
40#include <machine/kdb.h>
41#include <machine/pcb.h>
42#include <machine/setjmp.h>
43
44#include <ddb/ddb.h>
45#include <ddb/db_command.h>
46#include <ddb/db_sym.h>
47
48static dbbe_init_f db_init;
49static dbbe_trap_f db_trap;
50
51KDB_BACKEND(ddb, db_init, db_trace_self, db_trap);
52
53vm_offset_t ksym_start, ksym_end;
54
55boolean_t
56X_db_line_at_pc(db_symtab_t *symtab, c_db_sym_t sym, char **file, int *line,
57    db_expr_t off)
58{
59	return (FALSE);
60}
61
62c_db_sym_t
63X_db_lookup(db_symtab_t *symtab, const char *symbol)
64{
65	c_linker_sym_t lsym;
66	Elf_Sym *sym;
67
68	if (symtab->private == NULL) {
69		return ((c_db_sym_t)((!linker_ddb_lookup(symbol, &lsym))
70			? lsym : NULL));
71	} else {
72		sym = (Elf_Sym *)symtab->start;
73		while ((char *)sym < symtab->end) {
74			if (sym->st_name != 0 &&
75			    !strcmp(symtab->private + sym->st_name, symbol))
76				return ((c_db_sym_t)sym);
77			sym++;
78		}
79	}
80	return (NULL);
81}
82
83c_db_sym_t
84X_db_search_symbol(db_symtab_t *symtab, db_addr_t off, db_strategy_t strat,
85    db_expr_t *diffp)
86{
87	c_linker_sym_t lsym;
88	Elf_Sym *sym, *match;
89	unsigned long diff;
90
91	if (symtab->private == NULL) {
92		if (!linker_ddb_search_symbol((caddr_t)off, &lsym, &diff)) {
93			*diffp = (db_expr_t)diff;
94			return ((c_db_sym_t)lsym);
95		}
96		return (NULL);
97	}
98
99	diff = ~0UL;
100	match = NULL;
101	for (sym = (Elf_Sym*)symtab->start; (char*)sym < symtab->end; sym++) {
102		if (sym->st_name == 0)
103			continue;
104		if (off < sym->st_value)
105			continue;
106		if (ELF_ST_TYPE(sym->st_info) != STT_OBJECT &&
107		    ELF_ST_TYPE(sym->st_info) != STT_FUNC &&
108		    ELF_ST_TYPE(sym->st_info) != STT_NOTYPE)
109			continue;
110		if ((off - sym->st_value) > diff)
111			continue;
112		if ((off - sym->st_value) < diff) {
113			diff = off - sym->st_value;
114			match = sym;
115		} else {
116			if (match == NULL)
117				match = sym;
118			else if (ELF_ST_BIND(match->st_info) == STB_LOCAL &&
119			    ELF_ST_BIND(sym->st_info) != STB_LOCAL)
120				match = sym;
121		}
122		if (diff == 0) {
123			if (strat == DB_STGY_PROC &&
124			    ELF_ST_TYPE(sym->st_info) == STT_FUNC &&
125			    ELF_ST_BIND(sym->st_info) != STB_LOCAL)
126				break;
127			if (strat == DB_STGY_ANY &&
128			    ELF_ST_BIND(sym->st_info) != STB_LOCAL)
129				break;
130		}
131	}
132
133	*diffp = (match == NULL) ? off : diff;
134	return ((c_db_sym_t)match);
135}
136
137boolean_t
138X_db_sym_numargs(db_symtab_t *symtab, c_db_sym_t sym, int *nargp,
139    char **argp)
140{
141	return (FALSE);
142}
143
144void
145X_db_symbol_values(db_symtab_t *symtab, c_db_sym_t sym, const char **namep,
146    db_expr_t *valp)
147{
148	linker_symval_t lval;
149
150	if (symtab->private == NULL) {
151		linker_ddb_symbol_values((c_linker_sym_t)sym, &lval);
152		if (namep != NULL)
153			*namep = (const char*)lval.name;
154		if (valp != NULL)
155			*valp = (db_expr_t)lval.value;
156	} else {
157		if (namep != NULL)
158			*namep = (const char *)symtab->private +
159			    ((const Elf_Sym *)sym)->st_name;
160		if (valp != NULL)
161			*valp = (db_expr_t)((const Elf_Sym *)sym)->st_value;
162	}
163}
164
165static int
166db_init(void)
167{
168	uintptr_t symtab, strtab;
169	Elf_Size tabsz, strsz;
170
171	if (ksym_end > ksym_start && ksym_start != 0) {
172		symtab = ksym_start;
173		tabsz = *((Elf_Size*)symtab);
174		symtab += sizeof(Elf_Size);
175		strtab = symtab + tabsz;
176		strsz = *((Elf_Size*)strtab);
177		strtab += sizeof(Elf_Size);
178		if (strtab + strsz <= ksym_end) {
179			db_add_symbol_table((char *)symtab,
180			    (char *)(symtab + tabsz), "elf", (char *)strtab);
181		}
182	}
183	db_add_symbol_table(NULL, NULL, "kld", NULL);
184	return (1);	/* We're the default debugger. */
185}
186
187static int
188db_trap(int type, int code)
189{
190	jmp_buf jb;
191	void *prev_jb;
192	boolean_t bkpt, watchpt;
193
194	/*
195	 * Don't handle the trap if the console is unavailable (i.e. it
196	 * is in graphics mode).
197	 */
198	if (cnunavailable())
199		return (0);
200
201	bkpt = IS_BREAKPOINT_TRAP(type, code);
202	watchpt = IS_WATCHPOINT_TRAP(type, code);
203
204	if (db_stop_at_pc(&bkpt)) {
205		if (db_inst_count) {
206			db_printf("After %d instructions (%d loads, %d stores),\n",
207			    db_inst_count, db_load_count, db_store_count);
208		}
209		prev_jb = kdb_jmpbuf(jb);
210		if (setjmp(jb) == 0) {
211			db_dot = PC_REGS();
212			db_print_thread();
213			if (bkpt)
214				db_printf("Breakpoint at\t");
215			else if (watchpt)
216				db_printf("Watchpoint at\t");
217			else
218				db_printf("Stopped at\t");
219			db_print_loc_and_inst(db_dot);
220		}
221		db_command_loop();
222		(void)kdb_jmpbuf(prev_jb);
223	}
224
225	db_restart_at_pc(watchpt);
226
227	return (1);
228}
229