1/*
2 * Copyright (c) 2004 Marcel Moolenaar
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 *
9 * 1. Redistributions of source code must retain the above copyright
10 *    notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS OR
16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
18 * IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY DIRECT, INDIRECT,
19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25 */
26
27#include <sys/cdefs.h>
28__FBSDID("$FreeBSD$");
29
30#include <sys/param.h>
31#include <sys/proc.h>
32#include <machine/pcb.h>
33#include <machine/frame.h>
34#include <machine/segments.h>
35#include <machine/tss.h>
36#include <err.h>
37#include <kvm.h>
38#include <string.h>
39
40#include <defs.h>
41#include <target.h>
42#include <gdbthread.h>
43#include <inferior.h>
44#include <regcache.h>
45#include <frame-unwind.h>
46#include <i386-tdep.h>
47
48#include "kgdb.h"
49
50static int ofs_fix;
51
52CORE_ADDR
53kgdb_trgt_core_pcb(u_int cpuid)
54{
55	return (kgdb_trgt_stop_pcb(cpuid, sizeof(struct pcb)));
56}
57
58void
59kgdb_trgt_fetch_registers(int regno __unused)
60{
61	struct kthr *kt;
62	struct pcb pcb;
63
64	kt = kgdb_thr_lookup_tid(ptid_get_pid(inferior_ptid));
65	if (kt == NULL)
66		return;
67	if (kvm_read(kvm, kt->pcb, &pcb, sizeof(pcb)) != sizeof(pcb)) {
68		warnx("kvm_read: %s", kvm_geterr(kvm));
69		memset(&pcb, 0, sizeof(pcb));
70	}
71	supply_register(I386_EBX_REGNUM, (char *)&pcb.pcb_ebx);
72	supply_register(I386_ESP_REGNUM, (char *)&pcb.pcb_esp);
73	supply_register(I386_EBP_REGNUM, (char *)&pcb.pcb_ebp);
74	supply_register(I386_ESI_REGNUM, (char *)&pcb.pcb_esi);
75	supply_register(I386_EDI_REGNUM, (char *)&pcb.pcb_edi);
76	supply_register(I386_EIP_REGNUM, (char *)&pcb.pcb_eip);
77}
78
79void
80kgdb_trgt_store_registers(int regno __unused)
81{
82	fprintf_unfiltered(gdb_stderr, "XXX: %s\n", __func__);
83}
84
85void
86kgdb_trgt_new_objfile(struct objfile *objfile)
87{
88
89	/*
90	 * In revision 1.117 of i386/i386/exception.S trap handlers
91	 * were changed to pass trapframes by reference rather than
92	 * by value.  Detect this by seeing if the first instruction
93	 * at the 'calltrap' label is a "push %esp" which has the
94	 * opcode 0x54.
95	 */
96	if (kgdb_parse("((char *)calltrap)[0]") == 0x54)
97		ofs_fix = 4;
98	else
99		ofs_fix = 0;
100}
101
102struct kgdb_tss_cache {
103	CORE_ADDR	pc;
104	CORE_ADDR	sp;
105	CORE_ADDR	tss;
106};
107
108static int kgdb_trgt_tss_offset[15] = {
109	offsetof(struct i386tss, tss_eax),
110	offsetof(struct i386tss, tss_ecx),
111	offsetof(struct i386tss, tss_edx),
112	offsetof(struct i386tss, tss_ebx),
113	offsetof(struct i386tss, tss_esp),
114	offsetof(struct i386tss, tss_ebp),
115	offsetof(struct i386tss, tss_esi),
116	offsetof(struct i386tss, tss_edi),
117	offsetof(struct i386tss, tss_eip),
118	offsetof(struct i386tss, tss_eflags),
119	offsetof(struct i386tss, tss_cs),
120	offsetof(struct i386tss, tss_ss),
121	offsetof(struct i386tss, tss_ds),
122	offsetof(struct i386tss, tss_es),
123	offsetof(struct i386tss, tss_fs)
124};
125
126/*
127 * If the current thread is executing on a CPU, fetch the common_tss
128 * for that CPU.
129 *
130 * This is painful because 'struct pcpu' is variant sized, so we can't
131 * use it.  Instead, we lookup the GDT selector for this CPU and
132 * extract the base of the TSS from there.
133 */
134static CORE_ADDR
135kgdb_trgt_fetch_tss(void)
136{
137	struct kthr *kt;
138	struct segment_descriptor sd;
139	uintptr_t addr, cpu0prvpage, tss;
140
141	kt = kgdb_thr_lookup_tid(ptid_get_pid(inferior_ptid));
142	if (kt == NULL || kt->cpu == NOCPU)
143		return (0);
144
145	addr = kgdb_lookup("gdt");
146	if (addr == 0)
147		return (0);
148	addr += (kt->cpu * NGDT + GPROC0_SEL) * sizeof(sd);
149	if (kvm_read(kvm, addr, &sd, sizeof(sd)) != sizeof(sd)) {
150		warnx("kvm_read: %s", kvm_geterr(kvm));
151		return (0);
152	}
153	if (sd.sd_type != SDT_SYS386BSY) {
154		warnx("descriptor is not a busy TSS");
155		return (0);
156	}
157	tss = sd.sd_hibase << 24 | sd.sd_lobase;
158
159	/*
160	 * In SMP kernels, the TSS is stored as part of the per-CPU
161	 * data.  On older kernels, the CPU0's private page
162	 * is stored at an address that isn't mapped in minidumps.
163	 * However, the data is mapped at the alternate cpu0prvpage
164	 * address.  Thus, if the TSS is at the invalid address,
165	 * change it to be relative to cpu0prvpage instead.
166	 */
167	if (trunc_page(tss) == 0xffc00000) {
168		addr = kgdb_lookup("cpu0prvpage");
169		if (addr == 0)
170			return (0);
171		if (kvm_read(kvm, addr, &cpu0prvpage, sizeof(cpu0prvpage)) !=
172		    sizeof(cpu0prvpage)) {
173			warnx("kvm_read: %s", kvm_geterr(kvm));
174			return (0);
175		}
176		tss = cpu0prvpage + (tss & PAGE_MASK);
177	}
178	return ((CORE_ADDR)tss);
179}
180
181static struct kgdb_tss_cache *
182kgdb_trgt_tss_cache(struct frame_info *next_frame, void **this_cache)
183{
184	char buf[MAX_REGISTER_SIZE];
185	struct kgdb_tss_cache *cache;
186
187	cache = *this_cache;
188	if (cache == NULL) {
189		cache = FRAME_OBSTACK_ZALLOC(struct kgdb_tss_cache);
190		*this_cache = cache;
191		cache->pc = frame_func_unwind(next_frame);
192		frame_unwind_register(next_frame, SP_REGNUM, buf);
193		cache->sp = extract_unsigned_integer(buf,
194		    register_size(current_gdbarch, SP_REGNUM));
195		cache->tss = kgdb_trgt_fetch_tss();
196	}
197	return (cache);
198}
199
200static void
201kgdb_trgt_dblfault_this_id(struct frame_info *next_frame, void **this_cache,
202    struct frame_id *this_id)
203{
204	struct kgdb_tss_cache *cache;
205
206	cache = kgdb_trgt_tss_cache(next_frame, this_cache);
207	*this_id = frame_id_build(cache->sp, cache->pc);
208}
209
210static void
211kgdb_trgt_dblfault_prev_register(struct frame_info *next_frame,
212    void **this_cache, int regnum, int *optimizedp, enum lval_type *lvalp,
213    CORE_ADDR *addrp, int *realnump, void *valuep)
214{
215	char dummy_valuep[MAX_REGISTER_SIZE];
216	struct kgdb_tss_cache *cache;
217	int ofs, regsz;
218
219	regsz = register_size(current_gdbarch, regnum);
220
221	if (valuep == NULL)
222		valuep = dummy_valuep;
223	memset(valuep, 0, regsz);
224	*optimizedp = 0;
225	*addrp = 0;
226	*lvalp = not_lval;
227	*realnump = -1;
228
229	ofs = (regnum >= I386_EAX_REGNUM && regnum <= I386_FS_REGNUM)
230	    ? kgdb_trgt_tss_offset[regnum] : -1;
231	if (ofs == -1)
232		return;
233
234	cache = kgdb_trgt_tss_cache(next_frame, this_cache);
235	if (cache->tss == 0)
236		return;
237	*addrp = cache->tss + ofs;
238	*lvalp = lval_memory;
239	target_read_memory(*addrp, valuep, regsz);
240}
241
242static const struct frame_unwind kgdb_trgt_dblfault_unwind = {
243        UNKNOWN_FRAME,
244        &kgdb_trgt_dblfault_this_id,
245        &kgdb_trgt_dblfault_prev_register
246};
247
248struct kgdb_frame_cache {
249	int		frame_type;
250	CORE_ADDR	pc;
251	CORE_ADDR	sp;
252};
253#define	FT_NORMAL		1
254#define	FT_INTRFRAME		2
255#define	FT_INTRTRAPFRAME	3
256#define	FT_TIMERFRAME		4
257
258static int kgdb_trgt_frame_offset[15] = {
259	offsetof(struct trapframe, tf_eax),
260	offsetof(struct trapframe, tf_ecx),
261	offsetof(struct trapframe, tf_edx),
262	offsetof(struct trapframe, tf_ebx),
263	offsetof(struct trapframe, tf_esp),
264	offsetof(struct trapframe, tf_ebp),
265	offsetof(struct trapframe, tf_esi),
266	offsetof(struct trapframe, tf_edi),
267	offsetof(struct trapframe, tf_eip),
268	offsetof(struct trapframe, tf_eflags),
269	offsetof(struct trapframe, tf_cs),
270	offsetof(struct trapframe, tf_ss),
271	offsetof(struct trapframe, tf_ds),
272	offsetof(struct trapframe, tf_es),
273	offsetof(struct trapframe, tf_fs)
274};
275
276static struct kgdb_frame_cache *
277kgdb_trgt_frame_cache(struct frame_info *next_frame, void **this_cache)
278{
279	char buf[MAX_REGISTER_SIZE];
280	struct kgdb_frame_cache *cache;
281	char *pname;
282
283	cache = *this_cache;
284	if (cache == NULL) {
285		cache = FRAME_OBSTACK_ZALLOC(struct kgdb_frame_cache);
286		*this_cache = cache;
287		cache->pc = frame_func_unwind(next_frame);
288		find_pc_partial_function(cache->pc, &pname, NULL, NULL);
289		if (pname[0] != 'X')
290			cache->frame_type = FT_NORMAL;
291		else if (strcmp(pname, "Xtimerint") == 0)
292			cache->frame_type = FT_TIMERFRAME;
293		else if (strcmp(pname, "Xcpustop") == 0 ||
294		    strcmp(pname, "Xrendezvous") == 0 ||
295		    strcmp(pname, "Xipi_intr_bitmap_handler") == 0 ||
296		    strcmp(pname, "Xlazypmap") == 0)
297			cache->frame_type = FT_INTRTRAPFRAME;
298		else
299			cache->frame_type = FT_INTRFRAME;
300		frame_unwind_register(next_frame, SP_REGNUM, buf);
301		cache->sp = extract_unsigned_integer(buf,
302		    register_size(current_gdbarch, SP_REGNUM));
303	}
304	return (cache);
305}
306
307static void
308kgdb_trgt_trapframe_this_id(struct frame_info *next_frame, void **this_cache,
309    struct frame_id *this_id)
310{
311	struct kgdb_frame_cache *cache;
312
313	cache = kgdb_trgt_frame_cache(next_frame, this_cache);
314	*this_id = frame_id_build(cache->sp, cache->pc);
315}
316
317static void
318kgdb_trgt_trapframe_prev_register(struct frame_info *next_frame,
319    void **this_cache, int regnum, int *optimizedp, enum lval_type *lvalp,
320    CORE_ADDR *addrp, int *realnump, void *valuep)
321{
322	char dummy_valuep[MAX_REGISTER_SIZE];
323	struct kgdb_frame_cache *cache;
324	int ofs, regsz;
325
326	regsz = register_size(current_gdbarch, regnum);
327
328	if (valuep == NULL)
329		valuep = dummy_valuep;
330	memset(valuep, 0, regsz);
331	*optimizedp = 0;
332	*addrp = 0;
333	*lvalp = not_lval;
334	*realnump = -1;
335
336	ofs = (regnum >= I386_EAX_REGNUM && regnum <= I386_FS_REGNUM)
337	    ? kgdb_trgt_frame_offset[regnum] + ofs_fix : -1;
338	if (ofs == -1)
339		return;
340
341	cache = kgdb_trgt_frame_cache(next_frame, this_cache);
342	switch (cache->frame_type) {
343	case FT_NORMAL:
344		break;
345	case FT_INTRFRAME:
346		ofs += 4;
347		break;
348	case FT_TIMERFRAME:
349		break;
350	case FT_INTRTRAPFRAME:
351		ofs -= ofs_fix;
352		break;
353	default:
354		fprintf_unfiltered(gdb_stderr, "Correct FT_XXX frame offsets "
355		   "for %d\n", cache->frame_type);
356		break;
357	}
358	*addrp = cache->sp + ofs;
359	*lvalp = lval_memory;
360	target_read_memory(*addrp, valuep, regsz);
361}
362
363static const struct frame_unwind kgdb_trgt_trapframe_unwind = {
364        UNKNOWN_FRAME,
365        &kgdb_trgt_trapframe_this_id,
366        &kgdb_trgt_trapframe_prev_register
367};
368
369const struct frame_unwind *
370kgdb_trgt_trapframe_sniffer(struct frame_info *next_frame)
371{
372	char *pname;
373	CORE_ADDR pc;
374
375	pc = frame_pc_unwind(next_frame);
376	pname = NULL;
377	find_pc_partial_function(pc, &pname, NULL, NULL);
378	if (pname == NULL)
379		return (NULL);
380	if (strcmp(pname, "dblfault_handler") == 0)
381		return (&kgdb_trgt_dblfault_unwind);
382	if (strcmp(pname, "calltrap") == 0 ||
383	    (pname[0] == 'X' && pname[1] != '_'))
384		return (&kgdb_trgt_trapframe_unwind);
385	/* printf("%s: %llx =%s\n", __func__, pc, pname); */
386	return (NULL);
387}
388