aboutsummaryrefslogtreecommitdiff
path: root/gdb/frv-linux-tdep.c
blob: 5014c3ebbf3dda3f90dbc5a6db42930656ee0671 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
/* Target-dependent code for GNU/Linux running on the Fujitsu FR-V,
   for GDB.

   Copyright (C) 2004-2020 Free Software Foundation, Inc.

   This file is part of GDB.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 3 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */

#include "defs.h"
#include "gdbcore.h"
#include "target.h"
#include "frame.h"
#include "osabi.h"
#include "regcache.h"
#include "elf-bfd.h"
#include "elf/frv.h"
#include "frv-tdep.h"
#include "trad-frame.h"
#include "frame-unwind.h"
#include "regset.h"
#include "linux-tdep.h"
#include "gdbarch.h"

/* Define the size (in bytes) of an FR-V instruction.  */
static const int frv_instr_size = 4;

enum {
  NORMAL_SIGTRAMP = 1,
  RT_SIGTRAMP = 2
};

static int
frv_linux_pc_in_sigtramp (struct gdbarch *gdbarch, CORE_ADDR pc,
			  const char *name)
{
  enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
  gdb_byte buf[frv_instr_size];
  LONGEST instr;
  int retval = 0;

  if (target_read_memory (pc, buf, sizeof buf) != 0)
    return 0;

  instr = extract_unsigned_integer (buf, sizeof buf, byte_order);

  if (instr == 0x8efc0077)	/* setlos #__NR_sigreturn, gr7 */
    retval = NORMAL_SIGTRAMP;
  else if (instr == 0x8efc00ad)	/* setlos #__NR_rt_sigreturn, gr7 */
    retval = RT_SIGTRAMP;
  else
    return 0;

  if (target_read_memory (pc + frv_instr_size, buf, sizeof buf) != 0)
    return 0;
  instr = extract_unsigned_integer (buf, sizeof buf, byte_order);
  if (instr != 0xc0700000)	/* tira	gr0, 0 */
    return 0;

  /* If we get this far, we'll return a non-zero value, either
     NORMAL_SIGTRAMP (1) or RT_SIGTRAMP (2).  */
  return retval;
}

/* Given NEXT_FRAME, the "callee" frame of the sigtramp frame that we
   wish to decode, and REGNO, one of the frv register numbers defined
   in frv-tdep.h, return the address of the saved register (corresponding
   to REGNO) in the sigtramp frame.  Return -1 if the register is not
   found in the sigtramp frame.  The magic numbers in the code below
   were computed by examining the following kernel structs:

   From arch/frv/kernel/signal.c:

      struct sigframe
      {
	      void (*pretcode)(void);
	      int sig;
	      struct sigcontext sc;
	      unsigned long extramask[_NSIG_WORDS-1];
	      uint32_t retcode[2];
      };

      struct rt_sigframe
      {
	      void (*pretcode)(void);
	      int sig;
	      struct siginfo *pinfo;
	      void *puc;
	      struct siginfo info;
	      struct ucontext uc;
	      uint32_t retcode[2];
      };

   From include/asm-frv/ucontext.h:

      struct ucontext {
	      unsigned long		uc_flags;
	      struct ucontext		*uc_link;
	      stack_t			uc_stack;
	      struct sigcontext	uc_mcontext;
	      sigset_t		uc_sigmask;
      };

   From include/asm-frv/signal.h:

      typedef struct sigaltstack {
	      void *ss_sp;
	      int ss_flags;
	      size_t ss_size;
      } stack_t;

   From include/asm-frv/sigcontext.h:

      struct sigcontext {
	      struct user_context	sc_context;
	      unsigned long		sc_oldmask;
      } __attribute__((aligned(8)));

   From include/asm-frv/registers.h:
      struct user_int_regs
      {
	      unsigned long		psr;
	      unsigned long		isr;
	      unsigned long		ccr;
	      unsigned long		cccr;
	      unsigned long		lr;
	      unsigned long		lcr;
	      unsigned long		pc;
	      unsigned long		__status;
	      unsigned long		syscallno;
	      unsigned long		orig_gr8;
	      unsigned long		gner[2];
	      unsigned long long	iacc[1];

	      union {
		      unsigned long	tbr;
		      unsigned long	gr[64];
	      };
      };

      struct user_fpmedia_regs
      {
	      unsigned long	fr[64];
	      unsigned long	fner[2];
	      unsigned long	msr[2];
	      unsigned long	acc[8];
	      unsigned char	accg[8];
	      unsigned long	fsr[1];
      };

      struct user_context
      {
	      struct user_int_regs		i;
	      struct user_fpmedia_regs	f;

	      void *extension;
      } __attribute__((aligned(8)));  */

static LONGEST
frv_linux_sigcontext_reg_addr (struct frame_info *this_frame, int regno,
                               CORE_ADDR *sc_addr_cache_ptr)
{
  struct gdbarch *gdbarch = get_frame_arch (this_frame);
  enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
  CORE_ADDR sc_addr;

  if (sc_addr_cache_ptr && *sc_addr_cache_ptr)
    {
      sc_addr = *sc_addr_cache_ptr;
    }
  else
    {
      CORE_ADDR pc, sp;
      gdb_byte buf[4];
      int tramp_type;

      pc = get_frame_pc (this_frame);
      tramp_type = frv_linux_pc_in_sigtramp (gdbarch, pc, 0);

      get_frame_register (this_frame, sp_regnum, buf);
      sp = extract_unsigned_integer (buf, sizeof buf, byte_order);

      if (tramp_type == NORMAL_SIGTRAMP)
	{
	  /* For a normal sigtramp frame, the sigcontext struct starts
	     at SP + 8.  */
	  sc_addr = sp + 8;
	}
      else if (tramp_type == RT_SIGTRAMP)
	{
	  /* For a realtime sigtramp frame, SP + 12 contains a pointer
 	     to a ucontext struct.  The ucontext struct contains a
 	     sigcontext struct starting 24 bytes in.  (The offset of
 	     uc_mcontext within struct ucontext is derived as follows: 
 	     stack_t is a 12-byte struct and struct sigcontext is
 	     8-byte aligned.  This gives an offset of 8 + 12 + 4 (for
 	     padding) = 24.)  */
	  if (target_read_memory (sp + 12, buf, sizeof buf) != 0)
	    {
	      warning (_("Can't read realtime sigtramp frame."));
	      return 0;
	    }
	  sc_addr = extract_unsigned_integer (buf, sizeof buf, byte_order);
 	  sc_addr += 24;
	}
      else
	internal_error (__FILE__, __LINE__, _("not a signal trampoline"));

      if (sc_addr_cache_ptr)
	*sc_addr_cache_ptr = sc_addr;
    }

  switch (regno)
    {
    case psr_regnum :
      return sc_addr + 0;
    /* sc_addr + 4 has "isr", the Integer Status Register.  */
    case ccr_regnum :
      return sc_addr + 8;
    case cccr_regnum :
      return sc_addr + 12;
    case lr_regnum :
      return sc_addr + 16;
    case lcr_regnum :
      return sc_addr + 20;
    case pc_regnum :
      return sc_addr + 24;
    /* sc_addr + 28 is __status, the exception status.
       sc_addr + 32 is syscallno, the syscall number or -1.
       sc_addr + 36 is orig_gr8, the original syscall arg #1.
       sc_addr + 40 is gner[0].
       sc_addr + 44 is gner[1].  */
    case iacc0h_regnum :
      return sc_addr + 48;
    case iacc0l_regnum :
      return sc_addr + 52;
    default : 
      if (first_gpr_regnum <= regno && regno <= last_gpr_regnum)
	return sc_addr + 56 + 4 * (regno - first_gpr_regnum);
      else if (first_fpr_regnum <= regno && regno <= last_fpr_regnum)
	return sc_addr + 312 + 4 * (regno - first_fpr_regnum);
      else
	return -1;  /* not saved.  */
    }
}

/* Signal trampolines.  */

static struct trad_frame_cache *
frv_linux_sigtramp_frame_cache (struct frame_info *this_frame,
				void **this_cache)
{
  struct gdbarch *gdbarch = get_frame_arch (this_frame);
  enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
  struct trad_frame_cache *cache;
  CORE_ADDR addr;
  gdb_byte buf[4];
  int regnum;
  CORE_ADDR sc_addr_cache_val = 0;
  struct frame_id this_id;

  if (*this_cache)
    return (struct trad_frame_cache *) *this_cache;

  cache = trad_frame_cache_zalloc (this_frame);

  /* FIXME: cagney/2004-05-01: This is is long standing broken code.
     The frame ID's code address should be the start-address of the
     signal trampoline and not the current PC within that
     trampoline.  */
  get_frame_register (this_frame, sp_regnum, buf);
  addr = extract_unsigned_integer (buf, sizeof buf, byte_order);
  this_id = frame_id_build (addr, get_frame_pc (this_frame));
  trad_frame_set_id (cache, this_id);

  for (regnum = 0; regnum < frv_num_regs; regnum++)
    {
      LONGEST reg_addr = frv_linux_sigcontext_reg_addr (this_frame, regnum,
							&sc_addr_cache_val);
      if (reg_addr != -1)
	trad_frame_set_reg_addr (cache, regnum, reg_addr);
    }

  *this_cache = cache;
  return cache;
}

static void
frv_linux_sigtramp_frame_this_id (struct frame_info *this_frame,
				  void **this_cache,
				  struct frame_id *this_id)
{
  struct trad_frame_cache *cache
    = frv_linux_sigtramp_frame_cache (this_frame, this_cache);
  trad_frame_get_id (cache, this_id);
}

static struct value *
frv_linux_sigtramp_frame_prev_register (struct frame_info *this_frame,
					void **this_cache, int regnum)
{
  /* Make sure we've initialized the cache.  */
  struct trad_frame_cache *cache
    = frv_linux_sigtramp_frame_cache (this_frame, this_cache);
  return trad_frame_get_register (cache, this_frame, regnum);
}

static int
frv_linux_sigtramp_frame_sniffer (const struct frame_unwind *self,
				  struct frame_info *this_frame,
				  void **this_cache)
{
  struct gdbarch *gdbarch = get_frame_arch (this_frame);
  CORE_ADDR pc = get_frame_pc (this_frame);
  const char *name;

  find_pc_partial_function (pc, &name, NULL, NULL);
  if (frv_linux_pc_in_sigtramp (gdbarch, pc, name))
    return 1;

  return 0;
}

static const struct frame_unwind frv_linux_sigtramp_frame_unwind =
{
  SIGTRAMP_FRAME,
  default_frame_unwind_stop_reason,
  frv_linux_sigtramp_frame_this_id,
  frv_linux_sigtramp_frame_prev_register,
  NULL,
  frv_linux_sigtramp_frame_sniffer
};

/* The FRV kernel defines ELF_NGREG as 46.  We add 2 in order to include
   the loadmap addresses in the register set.  (See below for more info.)  */
#define FRV_ELF_NGREG (46 + 2)
typedef unsigned char frv_elf_greg_t[4];
typedef struct { frv_elf_greg_t reg[FRV_ELF_NGREG]; } frv_elf_gregset_t;

typedef unsigned char frv_elf_fpreg_t[4];
typedef struct
{
  frv_elf_fpreg_t fr[64];
  frv_elf_fpreg_t fner[2];
  frv_elf_fpreg_t msr[2];
  frv_elf_fpreg_t acc[8];
  unsigned char accg[8];
  frv_elf_fpreg_t fsr[1];
} frv_elf_fpregset_t;

/* Register maps.  */

static const struct regcache_map_entry frv_linux_gregmap[] =
  {
    { 1, psr_regnum, 4 },
    { 1, REGCACHE_MAP_SKIP, 4 }, /* isr */
    { 1, ccr_regnum, 4 },
    { 1, cccr_regnum, 4 },
    { 1, lr_regnum, 4 },
    { 1, lcr_regnum, 4 },
    { 1, pc_regnum, 4 },
    { 1, REGCACHE_MAP_SKIP, 4 }, /* __status */
    { 1, REGCACHE_MAP_SKIP, 4 }, /* syscallno */
    { 1, REGCACHE_MAP_SKIP, 4 }, /* orig_gr8 */
    { 1, gner0_regnum, 4 },
    { 1, gner1_regnum, 4 },
    { 1, REGCACHE_MAP_SKIP, 8 }, /* iacc0 */
    { 1, tbr_regnum, 4 },
    { 31, first_gpr_regnum + 1, 4 }, /* gr1 ... gr31 */

    /* Technically, the loadmap addresses are not part of `pr_reg' as
       found in the elf_prstatus struct.  The fields which communicate
       the loadmap address appear (by design) immediately after
       `pr_reg' though, and the BFD function elf32_frv_grok_prstatus()
       has been implemented to include these fields in the register
       section that it extracts from the core file.  So, for our
       purposes, they may be viewed as registers.  */

    { 1, fdpic_loadmap_exec_regnum, 4 },
    { 1, fdpic_loadmap_interp_regnum, 4 },
    { 0 }
  };

static const struct regcache_map_entry frv_linux_fpregmap[] =
  {
    { 64, first_fpr_regnum, 4 }, /* fr0 ... fr63 */
    { 1, fner0_regnum, 4 },
    { 1, fner1_regnum, 4 },
    { 1, msr0_regnum, 4 },
    { 1, msr1_regnum, 4 },
    { 8, acc0_regnum, 4 },	/* acc0 ... acc7 */
    { 1, accg0123_regnum, 4 },
    { 1, accg4567_regnum, 4 },
    { 1, fsr0_regnum, 4 },
    { 0 }
  };

/* Unpack an frv_elf_gregset_t into GDB's register cache.  */

static void 
frv_linux_supply_gregset (const struct regset *regset,
                          struct regcache *regcache,
			  int regnum, const void *gregs, size_t len)
{
  int regi;

  /* gr0 always contains 0.  Also, the kernel passes the TBR value in
     this slot.  */
  regcache->raw_supply_zeroed (first_gpr_regnum);

  /* Fill gr32, ..., gr63 with zeros. */
  for (regi = first_gpr_regnum + 32; regi <= last_gpr_regnum; regi++)
    regcache->raw_supply_zeroed (regi);

  regcache_supply_regset (regset, regcache, regnum, gregs, len);
}

/* FRV Linux kernel register sets.  */

static const struct regset frv_linux_gregset =
{
  frv_linux_gregmap,
  frv_linux_supply_gregset, regcache_collect_regset
};

static const struct regset frv_linux_fpregset =
{
  frv_linux_fpregmap,
  regcache_supply_regset, regcache_collect_regset
};

static void
frv_linux_iterate_over_regset_sections (struct gdbarch *gdbarch,
					iterate_over_regset_sections_cb *cb,
					void *cb_data,
					const struct regcache *regcache)
{
  cb (".reg", sizeof (frv_elf_gregset_t), sizeof (frv_elf_gregset_t),
      &frv_linux_gregset, NULL, cb_data);
  cb (".reg2", sizeof (frv_elf_fpregset_t), sizeof (frv_elf_fpregset_t),
      &frv_linux_fpregset, NULL, cb_data);
}


static void
frv_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
{
  linux_init_abi (info, gdbarch);

  /* Set the sigtramp frame sniffer.  */
  frame_unwind_append_unwinder (gdbarch, &frv_linux_sigtramp_frame_unwind); 

  set_gdbarch_iterate_over_regset_sections
    (gdbarch, frv_linux_iterate_over_regset_sections);
}

static enum gdb_osabi
frv_linux_elf_osabi_sniffer (bfd *abfd)
{
  int elf_flags;

  elf_flags = elf_elfheader (abfd)->e_flags;

  /* Assume GNU/Linux if using the FDPIC ABI.  If/when another OS shows
     up that uses this ABI, we'll need to start using .note sections
     or some such.  */
  if (elf_flags & EF_FRV_FDPIC)
    return GDB_OSABI_LINUX;
  else
    return GDB_OSABI_UNKNOWN;
}

void _initialize_frv_linux_tdep ();
void
_initialize_frv_linux_tdep ()
{
  gdbarch_register_osabi (bfd_arch_frv, 0, GDB_OSABI_LINUX,
			  frv_linux_init_abi);
  gdbarch_register_osabi_sniffer (bfd_arch_frv,
				  bfd_target_elf_flavour,
				  frv_linux_elf_osabi_sniffer);
}