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/param.h>
28#include <sys/systm.h>
29#include <sys/kdb.h>
30#include <sys/proc.h>
31#include <sys/reg.h>
32#include <sys/smp.h>
33#include <sys/stack.h>
34
35#include <machine/cpu.h>
36#include <machine/md_var.h>
37#include <machine/pcb.h>
38#include <machine/stack.h>
39
40#include <vm/vm.h>
41#include <vm/vm_param.h>
42#include <vm/pmap.h>
43
44#include <ddb/ddb.h>
45#include <ddb/db_access.h>
46#include <ddb/db_sym.h>
47#include <ddb/db_variables.h>
48
49static db_varfcn_t db_frame;
50static db_varfcn_t db_frame_seg;
51
52CTASSERT(sizeof(struct dbreg) == sizeof(((struct pcpu *)NULL)->pc_dbreg));
53
54/*
55 * Machine register set.
56 */
57#define	DB_OFFSET(x)	(db_expr_t *)offsetof(struct trapframe, x)
58struct db_variable db_regs[] = {
59	{ "cs",		DB_OFFSET(tf_cs),	db_frame_seg },
60	{ "ds",		DB_OFFSET(tf_ds),	db_frame_seg },
61	{ "es",		DB_OFFSET(tf_es),	db_frame_seg },
62	{ "fs",		DB_OFFSET(tf_fs),	db_frame_seg },
63	{ "gs",		DB_OFFSET(tf_gs),	db_frame_seg },
64	{ "ss",		DB_OFFSET(tf_ss),	db_frame_seg },
65	{ "rax",	DB_OFFSET(tf_rax),	db_frame },
66	{ "rcx",        DB_OFFSET(tf_rcx),	db_frame },
67	{ "rdx",	DB_OFFSET(tf_rdx),	db_frame },
68	{ "rbx",	DB_OFFSET(tf_rbx),	db_frame },
69	{ "rsp",	DB_OFFSET(tf_rsp),	db_frame },
70	{ "rbp",	DB_OFFSET(tf_rbp),	db_frame },
71	{ "rsi",	DB_OFFSET(tf_rsi),	db_frame },
72	{ "rdi",	DB_OFFSET(tf_rdi),	db_frame },
73	{ "r8",		DB_OFFSET(tf_r8),	db_frame },
74	{ "r9",		DB_OFFSET(tf_r9),	db_frame },
75	{ "r10",	DB_OFFSET(tf_r10),	db_frame },
76	{ "r11",	DB_OFFSET(tf_r11),	db_frame },
77	{ "r12",	DB_OFFSET(tf_r12),	db_frame },
78	{ "r13",	DB_OFFSET(tf_r13),	db_frame },
79	{ "r14",	DB_OFFSET(tf_r14),	db_frame },
80	{ "r15",	DB_OFFSET(tf_r15),	db_frame },
81	{ "rip",	DB_OFFSET(tf_rip),	db_frame },
82	{ "rflags",	DB_OFFSET(tf_rflags),	db_frame },
83};
84struct db_variable *db_eregs = db_regs + nitems(db_regs);
85
86static int
87db_frame_seg(struct db_variable *vp, db_expr_t *valuep, int op)
88{
89	uint16_t *reg;
90
91	if (kdb_frame == NULL)
92		return (0);
93
94	reg = (uint16_t *)((uintptr_t)kdb_frame + (db_expr_t)vp->valuep);
95	if (op == DB_VAR_GET)
96		*valuep = *reg;
97	else
98		*reg = *valuep;
99	return (1);
100}
101
102static int
103db_frame(struct db_variable *vp, db_expr_t *valuep, int op)
104{
105	long *reg;
106
107	if (kdb_frame == NULL)
108		return (0);
109
110	reg = (long *)((uintptr_t)kdb_frame + (db_expr_t)vp->valuep);
111	if (op == DB_VAR_GET)
112		*valuep = *reg;
113	else
114		*reg = *valuep;
115	return (1);
116}
117
118#define NORMAL		0
119#define	TRAP		1
120#define	INTERRUPT	2
121#define	SYSCALL		3
122
123static void
124db_print_stack_entry(const char *name, db_addr_t callpc, db_addr_t frame)
125{
126
127	db_printf("%s() at ", name != NULL ? name : "??");
128	db_printsym(callpc, DB_STGY_PROC);
129	if (frame != 0)
130		db_printf("/frame %#lx", frame);
131	db_printf("\n");
132}
133
134/*
135 * Figure out the next frame up in the call stack.
136 */
137static void
138db_nextframe(db_addr_t *fp, db_addr_t *ip, struct thread *td)
139{
140	struct trapframe *tf;
141	db_addr_t tf_addr;
142	int frame_type;
143	long rip, rsp, rbp;
144	db_expr_t offset;
145	c_db_sym_t sym;
146	const char *name;
147
148	rip = db_get_value(*fp + offsetof(struct amd64_frame, f_retaddr), 8,
149	    false);
150	rbp = db_get_value(*fp + offsetof(struct amd64_frame, f_frame), 8,
151	    false);
152
153	/*
154	 * Figure out frame type.  We look at the address just before
155	 * the saved instruction pointer as the saved EIP is after the
156	 * call function, and if the function being called is marked as
157	 * dead (such as panic() at the end of dblfault_handler()), then
158	 * the instruction at the saved EIP will be part of a different
159	 * function (syscall() in this example) rather than the one that
160	 * actually made the call.
161	 */
162	frame_type = NORMAL;
163	sym = db_search_symbol(rip - 1, DB_STGY_ANY, &offset);
164	db_symbol_values(sym, &name, NULL);
165	if (name != NULL) {
166		if (strcmp(name, "calltrap") == 0 ||
167		    strcmp(name, "fork_trampoline") == 0 ||
168		    strcmp(name, "mchk_calltrap") == 0 ||
169		    strcmp(name, "nmi_calltrap") == 0 ||
170		    strcmp(name, "Xdblfault") == 0)
171			frame_type = TRAP;
172		else if (strncmp(name, "Xatpic_intr", 11) == 0 ||
173		    strncmp(name, "Xapic_isr", 9) == 0 ||
174		    strcmp(name, "Xxen_intr_upcall") == 0 ||
175		    strcmp(name, "Xtimerint") == 0 ||
176		    strcmp(name, "Xipi_intr_bitmap_handler") == 0 ||
177		    strcmp(name, "Xcpustop") == 0 ||
178		    strcmp(name, "Xcpususpend") == 0 ||
179		    strcmp(name, "Xrendezvous") == 0)
180			frame_type = INTERRUPT;
181		else if (strcmp(name, "Xfast_syscall") == 0 ||
182		    strcmp(name, "Xfast_syscall_pti") == 0 ||
183		    strcmp(name, "fast_syscall_common") == 0)
184			frame_type = SYSCALL;
185#ifdef COMPAT_FREEBSD32
186		else if (strcmp(name, "Xint0x80_syscall") == 0)
187			frame_type = SYSCALL;
188#endif
189	}
190
191	/*
192	 * Normal frames need no special processing.
193	 */
194	if (frame_type == NORMAL) {
195		*ip = rip;
196		*fp = rbp;
197		return;
198	}
199
200	db_print_stack_entry(name, rip, *fp);
201
202	/*
203	 * Point to base of trapframe which is just above the
204	 * current frame.
205	 */
206	tf_addr = *fp + 16;
207
208	if (!__is_aligned(tf_addr, _Alignof(struct trapframe)) ||
209	    !INKERNEL(tf_addr)) {
210		db_printf("--- invalid trapframe %p\n", (void *)tf_addr);
211		*ip = 0;
212		*fp = 0;
213		return;
214	}
215	tf = (struct trapframe *)tf_addr;
216
217	rsp = tf->tf_rsp;
218	rip = tf->tf_rip;
219	rbp = tf->tf_rbp;
220	switch (frame_type) {
221	case TRAP:
222		db_printf("--- trap %#r", tf->tf_trapno);
223		break;
224	case SYSCALL:
225		db_printf("--- syscall");
226		db_decode_syscall(td, tf->tf_rax);
227		break;
228	case INTERRUPT:
229		db_printf("--- interrupt");
230		break;
231	default:
232		__assert_unreachable();
233	}
234	db_printf(", rip = %#lr, rsp = %#lr, rbp = %#lr ---\n", rip, rsp, rbp);
235
236	*ip = rip;
237	*fp = rbp;
238}
239
240static int __nosanitizeaddress __nosanitizememory
241db_backtrace(struct thread *td, struct trapframe *tf, db_addr_t frame,
242    db_addr_t pc, register_t sp, int count)
243{
244	db_addr_t actframe;
245	const char *name;
246	db_expr_t offset;
247	c_db_sym_t sym;
248	bool first;
249
250	if (count == -1)
251		count = 1024;
252
253	first = true;
254	while (count-- && !db_pager_quit) {
255		sym = db_search_symbol(pc, DB_STGY_ANY, &offset);
256		db_symbol_values(sym, &name, NULL);
257
258		/*
259		 * Attempt to determine a (possibly fake) frame that gives
260		 * the caller's pc.  It may differ from `frame' if the
261		 * current function never sets up a standard frame or hasn't
262		 * set one up yet or has just discarded one.  The last two
263		 * cases can be guessed fairly reliably for code generated
264		 * by gcc.  The first case is too much trouble to handle in
265		 * general because the amount of junk on the stack depends
266		 * on the pc (the special handling of "calltrap", etc. in
267		 * db_nextframe() works because the `next' pc is special).
268		 */
269		actframe = frame;
270		if (first) {
271			first = false;
272			if (sym == C_DB_SYM_NULL && sp != 0) {
273				/*
274				 * If a symbol couldn't be found, we've probably
275				 * jumped to a bogus location, so try and use
276				 * the return address to find our caller.
277				 */
278				db_print_stack_entry(name, pc, 0);
279				pc = db_get_value(sp, 8, false);
280				if (db_search_symbol(pc, DB_STGY_PROC,
281				    &offset) == C_DB_SYM_NULL)
282					break;
283				continue;
284			} else if (tf != NULL) {
285				int instr;
286
287				instr = db_get_value(pc, 4, false);
288				if ((instr & 0xffffffff) == 0xe5894855) {
289					/* pushq %rbp; movq %rsp, %rbp */
290					actframe = tf->tf_rsp - 8;
291				} else if ((instr & 0xffffff) == 0xe58948) {
292					/* movq %rsp, %rbp */
293					actframe = tf->tf_rsp;
294					if (tf->tf_rbp == 0) {
295						/* Fake frame better. */
296						frame = actframe;
297					}
298				} else if ((instr & 0xff) == 0xc3) {
299					/* ret */
300					actframe = tf->tf_rsp - 8;
301				} else if (offset == 0) {
302					/* Probably an assembler symbol. */
303					actframe = tf->tf_rsp - 8;
304				}
305			} else if (name != NULL &&
306			    strcmp(name, "fork_trampoline") == 0) {
307				/*
308				 * Don't try to walk back on a stack for a
309				 * process that hasn't actually been run yet.
310				 */
311				db_print_stack_entry(name, pc, actframe);
312				break;
313			}
314		}
315
316		db_print_stack_entry(name, pc, actframe);
317
318		if (actframe != frame) {
319			/* `frame' belongs to caller. */
320			pc = db_get_value(actframe +
321			    offsetof(struct amd64_frame, f_retaddr), 8, false);
322			continue;
323		}
324
325		db_nextframe(&frame, &pc, td);
326		if (frame == 0)
327			break;
328
329		if (!__is_aligned(frame, _Alignof(struct amd64_frame)) ||
330		    !INKERNEL(frame)) {
331			if (INKERNEL(pc)) {
332				sym = db_search_symbol(pc, DB_STGY_ANY,
333				    &offset);
334				db_symbol_values(sym, &name, NULL);
335				db_print_stack_entry(name, pc, frame);
336				break;
337			}
338			break;
339		}
340	}
341
342	return (0);
343}
344
345void
346db_trace_self(void)
347{
348	db_addr_t callpc, frame;
349	register_t rbp;
350
351	__asm __volatile("movq %%rbp,%0" : "=r" (rbp));
352	callpc = db_get_value(rbp + offsetof(struct amd64_frame, f_retaddr), 8,
353	    false);
354	frame = db_get_value(rbp + offsetof(struct amd64_frame, f_frame), 8,
355	    false);
356	db_backtrace(curthread, NULL, frame, callpc, 0, -1);
357}
358
359int
360db_trace_thread(struct thread *thr, int count)
361{
362	struct pcb *ctx;
363	struct trapframe *tf;
364
365	ctx = kdb_thr_ctx(thr);
366	tf = thr == kdb_thread ? kdb_frame : NULL;
367	return (db_backtrace(thr, tf, ctx->pcb_rbp, ctx->pcb_rip, ctx->pcb_rsp,
368	    count));
369}
370
371void
372db_md_list_watchpoints(void)
373{
374
375	dbreg_list_watchpoints();
376}
377