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: releng/11.0/gnu/usr.bin/gdb/kgdb/trgt_arm.c 298358 2016-04-20 17:58:13Z wma $");
29
30#include <sys/types.h>
31#ifndef CROSS_DEBUGGER
32#include <machine/pcb.h>
33#include <machine/frame.h>
34#include <machine/armreg.h>
35#endif
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 <arm-tdep.h>
47
48#include "kgdb.h"
49
50CORE_ADDR
51kgdb_trgt_core_pcb(u_int cpuid)
52{
53#ifndef CROSS_DEBUGGER
54	return (kgdb_trgt_stop_pcb(cpuid, sizeof(struct pcb)));
55#else
56	return -1;
57#endif
58}
59
60void
61kgdb_trgt_fetch_registers(int regno __unused)
62{
63#ifndef CROSS_DEBUGGER
64	struct kthr *kt;
65	struct pcb pcb;
66	int i;
67
68	kt = kgdb_thr_lookup_tid(ptid_get_pid(inferior_ptid));
69	if (kt == NULL)
70		return;
71	if (kvm_read(kvm, kt->pcb, &pcb, sizeof(pcb)) != sizeof(pcb)) {
72		warnx("kvm_read: %s", kvm_geterr(kvm));
73		memset(&pcb, 0, sizeof(pcb));
74	}
75	for (i = ARM_A1_REGNUM + 4; i <= ARM_SP_REGNUM; i++) {
76		supply_register(i, (char *)&pcb.pcb_regs.sf_r4 +
77		    (i - (ARM_A1_REGNUM + 4 )) * 4);
78	}
79	supply_register(ARM_PC_REGNUM, (char *)&pcb.pcb_regs.sf_pc);
80	supply_register(ARM_LR_REGNUM, (char *)&pcb.pcb_regs.sf_lr);
81#endif
82}
83
84void
85kgdb_trgt_store_registers(int regno __unused)
86{
87	fprintf_unfiltered(gdb_stderr, "XXX: %s\n", __func__);
88}
89
90void
91kgdb_trgt_new_objfile(struct objfile *objfile)
92{
93}
94
95#ifndef CROSS_DEBUGGER
96struct kgdb_frame_cache {
97	CORE_ADDR	fp;
98	CORE_ADDR	sp;
99	CORE_ADDR	pc;
100};
101
102static int kgdb_trgt_frame_offset[26] = {
103	offsetof(struct trapframe, tf_r0),
104	offsetof(struct trapframe, tf_r1),
105	offsetof(struct trapframe, tf_r2),
106	offsetof(struct trapframe, tf_r3),
107	offsetof(struct trapframe, tf_r4),
108	offsetof(struct trapframe, tf_r5),
109	offsetof(struct trapframe, tf_r6),
110	offsetof(struct trapframe, tf_r7),
111	offsetof(struct trapframe, tf_r8),
112	offsetof(struct trapframe, tf_r9),
113	offsetof(struct trapframe, tf_r10),
114	offsetof(struct trapframe, tf_r11),
115	offsetof(struct trapframe, tf_r12),
116	offsetof(struct trapframe, tf_svc_sp),
117	offsetof(struct trapframe, tf_svc_lr),
118	offsetof(struct trapframe, tf_pc),
119	-1, -1, -1, -1, -1, -1, -1, -1, -1,
120	offsetof(struct trapframe, tf_spsr)
121};
122
123static struct kgdb_frame_cache *
124kgdb_trgt_frame_cache(struct frame_info *next_frame, void **this_cache)
125{
126	char buf[MAX_REGISTER_SIZE];
127	struct kgdb_frame_cache *cache;
128
129	cache = *this_cache;
130	if (cache == NULL) {
131		cache = FRAME_OBSTACK_ZALLOC(struct kgdb_frame_cache);
132		*this_cache = cache;
133		frame_unwind_register(next_frame, ARM_SP_REGNUM, buf);
134		cache->sp = extract_unsigned_integer(buf,
135		    register_size(current_gdbarch, ARM_SP_REGNUM));
136		frame_unwind_register(next_frame, ARM_FP_REGNUM, buf);
137		cache->fp = extract_unsigned_integer(buf,
138		    register_size(current_gdbarch, ARM_FP_REGNUM));
139		cache->pc = frame_func_unwind(next_frame);
140	}
141	return (cache);
142}
143
144static int is_undef;
145
146static void
147kgdb_trgt_trapframe_this_id(struct frame_info *next_frame, void **this_cache,
148    struct frame_id *this_id)
149{
150	struct kgdb_frame_cache *cache;
151
152	cache = kgdb_trgt_frame_cache(next_frame, this_cache);
153	*this_id = frame_id_build(cache->sp, cache->pc);
154}
155
156static void
157kgdb_trgt_trapframe_prev_register(struct frame_info *next_frame,
158    void **this_cache, int regnum, int *optimizedp, enum lval_type *lvalp,
159    CORE_ADDR *addrp, int *realnump, void *valuep)
160{
161	char dummy_valuep[MAX_REGISTER_SIZE];
162	struct kgdb_frame_cache *cache;
163	int ofs, regsz;
164	CORE_ADDR sp;
165
166	regsz = register_size(current_gdbarch, regnum);
167
168	if (valuep == NULL)
169		valuep = dummy_valuep;
170	memset(valuep, 0, regsz);
171	*optimizedp = 0;
172	*addrp = 0;
173	*lvalp = not_lval;
174	*realnump = -1;
175
176	ofs = (regnum >= 0 && regnum <= ARM_PS_REGNUM)
177	    ? kgdb_trgt_frame_offset[regnum] : -1;
178	if (ofs == -1)
179		return;
180
181	cache = kgdb_trgt_frame_cache(next_frame, this_cache);
182	sp = cache->sp;
183
184	ofs = kgdb_trgt_frame_offset[regnum];
185	*addrp = sp + ofs;
186	*lvalp = lval_memory;
187	target_read_memory(*addrp, valuep, regsz);
188}
189
190static const struct frame_unwind kgdb_trgt_trapframe_unwind = {
191        UNKNOWN_FRAME,
192        &kgdb_trgt_trapframe_this_id,
193        &kgdb_trgt_trapframe_prev_register
194};
195#endif
196
197const struct frame_unwind *
198kgdb_trgt_trapframe_sniffer(struct frame_info *next_frame)
199{
200#ifndef CROSS_DEBUGGER
201	char *pname;
202	CORE_ADDR pc;
203
204	pc = frame_pc_unwind(next_frame);
205	pname = NULL;
206	find_pc_partial_function(pc, &pname, NULL, NULL);
207	if (pname == NULL) {
208		is_undef = 0;
209		return (NULL);
210	}
211	if (!strcmp(pname, "undefinedinstruction"))
212		is_undef = 1;
213	if (strcmp(pname, "Laddress_exception_entry") == 0 ||
214	    strcmp(pname, "undefined_entry") == 0 ||
215	    strcmp(pname, "exception_exit") == 0 ||
216	    strcmp(pname, "Laddress_exception_msg") == 0 ||
217	    strcmp(pname, "irq_entry") == 0)
218		return (&kgdb_trgt_trapframe_unwind);
219	if (!strcmp(pname, "undefinedinstruction"))
220		is_undef = 1;
221	else
222		is_undef = 0;
223#endif
224	return (NULL);
225}
226
227/*
228 * This function ensures, that the PC is inside the
229 * function section which is understood by GDB.
230 *
231 * Return 0 when fixup is necessary, -1 otherwise.
232 */
233int
234kgdb_trgt_pc_fixup(CORE_ADDR *pc)
235{
236#ifndef CROSS_DEBUGGER
237	struct minimal_symbol *msymbol;
238	int valpc;
239
240	/*
241	 * exception_exit and swi_exit are special. These functions
242	 * are artificially injected into the stack to be executed
243	 * as the last entry in calling chain when all functions exit.
244	 * Treat them differently.
245	 */
246	msymbol = lookup_minimal_symbol_by_pc(*pc);
247	if (msymbol != NULL) {
248		if (strcmp(DEPRECATED_SYMBOL_NAME(msymbol), "exception_exit") == 0)
249			return (0);
250		if (strcmp(DEPRECATED_SYMBOL_NAME(msymbol), "swi_exit") == 0)
251			return (0);
252	}
253
254	/*
255	 * kdb_enter contains an invalid instruction which is supposed
256	 * to generate a trap. BFD does not understand it and treats
257	 * this part of function as a separate function. Move PC
258	 * two instruction earlier to be inside kdb_enter section.
259	 */
260	target_read_memory(*pc - 4, (char*)&valpc, 4);
261	if (valpc == 0xe7ffffff) {
262		*pc = *pc - 8;
263		return (0);
264	}
265
266	/*
267	 * When the panic/vpanic is the last (noreturn) function,
268	 * the bottom of the calling function looks as below.
269	 *   mov lr, pc
270	 *   b panic
271	 * Normally, GDB is not able to detect function boundaries,
272	 * so move the PC two instruction earlier where it can deal
273	 * with it.
274	 * Match this pair of instructions: mov lr, pc followed with
275	 * non-linked branch.
276	 */
277	if ((valpc & 0xff000000) == 0xea000000) {
278		target_read_memory(*pc - 8, (char*)&valpc, 4);
279		if (valpc == 0xe1a0e00f) {
280			*pc -= 8;
281			return (0);
282		}
283	}
284#endif
285	return (-1);
286}
287