db_main.c revision 174914 
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 174914 2007-12-26 09:33:19Z rwatson $");
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#include <sys/sysctl.h>
40
41#include <machine/kdb.h>
42#include <machine/pcb.h>
43#include <machine/setjmp.h>
44
45#include <ddb/ddb.h>
46#include <ddb/db_command.h>
47#include <ddb/db_sym.h>
48
49SYSCTL_NODE(_debug, OID_AUTO, ddb, CTLFLAG_RW, 0, "DDB settings");
50
51static dbbe_init_f db_init;
52static dbbe_trap_f db_trap;
53static dbbe_trace_f db_trace_self_wrapper;
54
55KDB_BACKEND(ddb, db_init, db_trace_self_wrapper, db_trap);
56
57vm_offset_t ksym_start, ksym_end;
58
59boolean_t
60X_db_line_at_pc(db_symtab_t *symtab, c_db_sym_t sym, char **file, int *line,
61    db_expr_t off)
62{
63	return (FALSE);
64}
65
66c_db_sym_t
67X_db_lookup(db_symtab_t *symtab, const char *symbol)
68{
69	c_linker_sym_t lsym;
70	Elf_Sym *sym;
71
72	if (symtab->private == NULL) {
73		return ((c_db_sym_t)((!linker_ddb_lookup(symbol, &lsym))
74			? lsym : NULL));
75	} else {
76		sym = (Elf_Sym *)symtab->start;
77		while ((char *)sym < symtab->end) {
78			if (sym->st_name != 0 &&
79			    !strcmp(symtab->private + sym->st_name, symbol))
80				return ((c_db_sym_t)sym);
81			sym++;
82		}
83	}
84	return (NULL);
85}
86
87c_db_sym_t
88X_db_search_symbol(db_symtab_t *symtab, db_addr_t off, db_strategy_t strat,
89    db_expr_t *diffp)
90{
91	c_linker_sym_t lsym;
92	Elf_Sym *sym, *match;
93	unsigned long diff;
94
95	if (symtab->private == NULL) {
96		if (!linker_ddb_search_symbol((caddr_t)off, &lsym, &diff)) {
97			*diffp = (db_expr_t)diff;
98			return ((c_db_sym_t)lsym);
99		}
100		return (NULL);
101	}
102
103	diff = ~0UL;
104	match = NULL;
105	for (sym = (Elf_Sym*)symtab->start; (char*)sym < symtab->end; sym++) {
106		if (sym->st_name == 0)
107			continue;
108		if (off < sym->st_value)
109			continue;
110		if (ELF_ST_TYPE(sym->st_info) != STT_OBJECT &&
111		    ELF_ST_TYPE(sym->st_info) != STT_FUNC &&
112		    ELF_ST_TYPE(sym->st_info) != STT_NOTYPE)
113			continue;
114		if ((off - sym->st_value) > diff)
115			continue;
116		if ((off - sym->st_value) < diff) {
117			diff = off - sym->st_value;
118			match = sym;
119		} else {
120			if (match == NULL)
121				match = sym;
122			else if (ELF_ST_BIND(match->st_info) == STB_LOCAL &&
123			    ELF_ST_BIND(sym->st_info) != STB_LOCAL)
124				match = sym;
125		}
126		if (diff == 0) {
127			if (strat == DB_STGY_PROC &&
128			    ELF_ST_TYPE(sym->st_info) == STT_FUNC &&
129			    ELF_ST_BIND(sym->st_info) != STB_LOCAL)
130				break;
131			if (strat == DB_STGY_ANY &&
132			    ELF_ST_BIND(sym->st_info) != STB_LOCAL)
133				break;
134		}
135	}
136
137	*diffp = (match == NULL) ? off : diff;
138	return ((c_db_sym_t)match);
139}
140
141boolean_t
142X_db_sym_numargs(db_symtab_t *symtab, c_db_sym_t sym, int *nargp,
143    char **argp)
144{
145	return (FALSE);
146}
147
148void
149X_db_symbol_values(db_symtab_t *symtab, c_db_sym_t sym, const char **namep,
150    db_expr_t *valp)
151{
152	linker_symval_t lval;
153
154	if (symtab->private == NULL) {
155		linker_ddb_symbol_values((c_linker_sym_t)sym, &lval);
156		if (namep != NULL)
157			*namep = (const char*)lval.name;
158		if (valp != NULL)
159			*valp = (db_expr_t)lval.value;
160	} else {
161		if (namep != NULL)
162			*namep = (const char *)symtab->private +
163			    ((const Elf_Sym *)sym)->st_name;
164		if (valp != NULL)
165			*valp = (db_expr_t)((const Elf_Sym *)sym)->st_value;
166	}
167}
168
169static int
170db_init(void)
171{
172	uintptr_t symtab, strtab;
173	Elf_Size tabsz, strsz;
174
175	if (ksym_end > ksym_start && ksym_start != 0) {
176		symtab = ksym_start;
177		tabsz = *((Elf_Size*)symtab);
178		symtab += sizeof(Elf_Size);
179		strtab = symtab + tabsz;
180		strsz = *((Elf_Size*)strtab);
181		strtab += sizeof(Elf_Size);
182		if (strtab + strsz <= ksym_end) {
183			db_add_symbol_table((char *)symtab,
184			    (char *)(symtab + tabsz), "elf", (char *)strtab);
185		}
186	}
187	db_add_symbol_table(NULL, NULL, "kld", NULL);
188	return (1);	/* We're the default debugger. */
189}
190
191static int
192db_trap(int type, int code)
193{
194	jmp_buf jb;
195	void *prev_jb;
196	boolean_t bkpt, watchpt;
197	const char *why;
198
199	/*
200	 * Don't handle the trap if the console is unavailable (i.e. it
201	 * is in graphics mode).
202	 */
203	if (cnunavailable())
204		return (0);
205
206	bkpt = IS_BREAKPOINT_TRAP(type, code);
207	watchpt = IS_WATCHPOINT_TRAP(type, code);
208
209	if (db_stop_at_pc(&bkpt)) {
210		if (db_inst_count) {
211			db_printf("After %d instructions (%d loads, %d stores),\n",
212			    db_inst_count, db_load_count, db_store_count);
213		}
214		prev_jb = kdb_jmpbuf(jb);
215		if (setjmp(jb) == 0) {
216			db_dot = PC_REGS();
217			db_print_thread();
218			if (bkpt)
219				db_printf("Breakpoint at\t");
220			else if (watchpt)
221				db_printf("Watchpoint at\t");
222			else
223				db_printf("Stopped at\t");
224			db_print_loc_and_inst(db_dot);
225		}
226		why = kdb_why;
227		db_script_kdbenter(why != KDB_WHY_UNSET ? why : "unknown");
228		db_command_loop();
229		(void)kdb_jmpbuf(prev_jb);
230	}
231
232	db_restart_at_pc(watchpt);
233
234	return (1);
235}
236
237static void
238db_trace_self_wrapper(void)
239{
240	jmp_buf jb;
241	void *prev_jb;
242
243	prev_jb = kdb_jmpbuf(jb);
244	if (setjmp(jb) == 0)
245		db_trace_self();
246	(void)kdb_jmpbuf(prev_jb);
247}
248