[deliverable/binutils-gdb.git] / gdb / alphanbsd-tdep.c

/* Target-dependent code for NetBSD/alpha.

   Copyright (C) 2002-2016 Free Software Foundation, Inc.

   Contributed by Wasabi Systems, 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 "frame.h"
#include "gdbcore.h"
#include "osabi.h"
#include "regcache.h"
#include "regset.h"
#include "value.h"

#include "alpha-tdep.h"
#include "alphabsd-tdep.h"
#include "nbsd-tdep.h"
#include "solib-svr4.h"
#include "target.h"

/* Core file support.  */

/* Even though NetBSD/alpha used ELF since day one, it used the
   traditional a.out-style core dump format before NetBSD 1.6.  */

/* Sizeof `struct reg' in <machine/reg.h>.  */
#define ALPHANBSD_SIZEOF_GREGS	(32 * 8)

/* Sizeof `struct fpreg' in <machine/reg.h.  */
#define ALPHANBSD_SIZEOF_FPREGS	((32 * 8) + 8)

/* Supply register REGNUM from the buffer specified by FPREGS and LEN
   in the floating-point register set REGSET to register cache
   REGCACHE.  If REGNUM is -1, do this for all registers in REGSET.  */

static void
alphanbsd_supply_fpregset (const struct regset *regset,
			   struct regcache *regcache,
			   int regnum, const void *fpregs, size_t len)
{
  const gdb_byte *regs = (const gdb_byte *) fpregs;
  int i;

  gdb_assert (len >= ALPHANBSD_SIZEOF_FPREGS);

  for (i = ALPHA_FP0_REGNUM; i < ALPHA_FP0_REGNUM + 31; i++)
    {
      if (regnum == i || regnum == -1)
	regcache_raw_supply (regcache, i, regs + (i - ALPHA_FP0_REGNUM) * 8);
    }

  if (regnum == ALPHA_FPCR_REGNUM || regnum == -1)
    regcache_raw_supply (regcache, ALPHA_FPCR_REGNUM, regs + 32 * 8);
}

/* Supply register REGNUM from the buffer specified by GREGS and LEN
   in the general-purpose register set REGSET to register cache
   REGCACHE.  If REGNUM is -1, do this for all registers in REGSET.  */

static void
alphanbsd_aout_supply_gregset (const struct regset *regset,
			       struct regcache *regcache,
			       int regnum, const void *gregs, size_t len)
{
  const gdb_byte *regs = (const gdb_byte *) gregs;
  int i;

  /* Table to map a GDB register number to a trapframe register index.  */
  static const int regmap[] =
  {
     0,   1,   2,   3,
     4,   5,   6,   7,
     8,   9,  10,  11,
    12,  13,  14,  15, 
    30,  31,  32,  16, 
    17,  18,  19,  20,
    21,  22,  23,  24,
    25,  29,  26
  };

  gdb_assert (len >= ALPHANBSD_SIZEOF_GREGS);

  for (i = 0; i < ARRAY_SIZE(regmap); i++)
    {
      if (regnum == i || regnum == -1)
	regcache_raw_supply (regcache, i, regs + regmap[i] * 8);
    }

  if (regnum == ALPHA_PC_REGNUM || regnum == -1)
    regcache_raw_supply (regcache, ALPHA_PC_REGNUM, regs + 31 * 8);

  if (len >= ALPHANBSD_SIZEOF_GREGS + ALPHANBSD_SIZEOF_FPREGS)
    {
      regs += ALPHANBSD_SIZEOF_GREGS;
      len -= ALPHANBSD_SIZEOF_GREGS;
      alphanbsd_supply_fpregset (regset, regcache, regnum, regs, len);
    }
}

/* Supply register REGNUM from the buffer specified by GREGS and LEN
   in the general-purpose register set REGSET to register cache
   REGCACHE.  If REGNUM is -1, do this for all registers in REGSET.  */

static void
alphanbsd_supply_gregset (const struct regset *regset,
			  struct regcache *regcache,
			  int regnum, const void *gregs, size_t len)
{
  const gdb_byte *regs = (const gdb_byte *) gregs;
  int i;

  if (len >= ALPHANBSD_SIZEOF_GREGS + ALPHANBSD_SIZEOF_FPREGS)
    {
      alphanbsd_aout_supply_gregset (regset, regcache, regnum, gregs, len);
      return;
    }

  for (i = 0; i < ALPHA_ZERO_REGNUM; i++)
    {
      if (regnum == i || regnum == -1)
	regcache_raw_supply (regcache, i, regs + i * 8);
    }

  if (regnum == ALPHA_PC_REGNUM || regnum == -1)
    regcache_raw_supply (regcache, ALPHA_PC_REGNUM, regs + 31 * 8);
}

/* NetBSD/alpha register sets.  */

static const struct regset alphanbsd_gregset =
{
  NULL,
  alphanbsd_supply_gregset,
  NULL,
  REGSET_VARIABLE_SIZE
};

static const struct regset alphanbsd_fpregset =
{
  NULL,
  alphanbsd_supply_fpregset
};

/* Iterate over supported core file register note sections. */

void
alphanbsd_iterate_over_regset_sections (struct gdbarch *gdbarch,
					iterate_over_regset_sections_cb *cb,
					void *cb_data,
					const struct regcache *regcache)
{
  cb (".reg", ALPHANBSD_SIZEOF_GREGS, &alphanbsd_gregset, NULL, cb_data);
  cb (".reg2", ALPHANBSD_SIZEOF_FPREGS, &alphanbsd_fpregset, NULL, cb_data);
}
\f

/* Signal trampolines.  */

/* Under NetBSD/alpha, signal handler invocations can be identified by the
   designated code sequence that is used to return from a signal handler.
   In particular, the return address of a signal handler points to the
   following code sequence:

	ldq	a0, 0(sp)
	lda	sp, 16(sp)
	lda	v0, 295(zero)	# __sigreturn14
	call_pal callsys

   Each instruction has a unique encoding, so we simply attempt to match
   the instruction the PC is pointing to with any of the above instructions.
   If there is a hit, we know the offset to the start of the designated
   sequence and can then check whether we really are executing in the
   signal trampoline.  If not, -1 is returned, otherwise the offset from the
   start of the return sequence is returned.  */
static const gdb_byte sigtramp_retcode[] =
{
  0x00, 0x00, 0x1e, 0xa6,	/* ldq a0, 0(sp) */
  0x10, 0x00, 0xde, 0x23,	/* lda sp, 16(sp) */
  0x27, 0x01, 0x1f, 0x20,	/* lda v0, 295(zero) */
  0x83, 0x00, 0x00, 0x00,	/* call_pal callsys */
};
#define RETCODE_NWORDS		4
#define RETCODE_SIZE		(RETCODE_NWORDS * 4)

static LONGEST
alphanbsd_sigtramp_offset (struct gdbarch *gdbarch, CORE_ADDR pc)
{
  gdb_byte ret[RETCODE_SIZE], w[4];
  LONGEST off;
  int i;

  if (target_read_memory (pc, w, 4) != 0)
    return -1;

  for (i = 0; i < RETCODE_NWORDS; i++)
    {
      if (memcmp (w, sigtramp_retcode + (i * 4), 4) == 0)
	break;
    }
  if (i == RETCODE_NWORDS)
    return (-1);

  off = i * 4;
  pc -= off;

  if (target_read_memory (pc, ret, sizeof (ret)) != 0)
    return -1;

  if (memcmp (ret, sigtramp_retcode, RETCODE_SIZE) == 0)
    return off;

  return -1;
}

static int
alphanbsd_pc_in_sigtramp (struct gdbarch *gdbarch,
		 	  CORE_ADDR pc, const char *func_name)
{
  return (nbsd_pc_in_sigtramp (pc, func_name)
	  || alphanbsd_sigtramp_offset (gdbarch, pc) >= 0);
}

static CORE_ADDR
alphanbsd_sigcontext_addr (struct frame_info *frame)
{
  /* FIXME: This is not correct for all versions of NetBSD/alpha.
     We will probably need to disassemble the trampoline to figure
     out which trampoline frame type we have.  */
  if (!get_next_frame (frame))
    return 0;
  return get_frame_base (get_next_frame (frame));
}
\f

static void
alphanbsd_init_abi (struct gdbarch_info info,
                    struct gdbarch *gdbarch)
{
  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);

  /* Hook into the DWARF CFI frame unwinder.  */
  alpha_dwarf2_init_abi (info, gdbarch);

  /* Hook into the MDEBUG frame unwinder.  */
  alpha_mdebug_init_abi (info, gdbarch);

  /* NetBSD/alpha does not provide single step support via ptrace(2); we
     must use software single-stepping.  */
  set_gdbarch_software_single_step (gdbarch, alpha_software_single_step);

  /* NetBSD/alpha has SVR4-style shared libraries.  */
  set_solib_svr4_fetch_link_map_offsets
    (gdbarch, svr4_lp64_fetch_link_map_offsets);

  tdep->dynamic_sigtramp_offset = alphanbsd_sigtramp_offset;
  tdep->pc_in_sigtramp = alphanbsd_pc_in_sigtramp;
  tdep->sigcontext_addr = alphanbsd_sigcontext_addr;

  tdep->jb_pc = 2;
  tdep->jb_elt_size = 8;

  set_gdbarch_iterate_over_regset_sections
    (gdbarch, alphanbsd_iterate_over_regset_sections);
}
\f

static enum gdb_osabi
alphanbsd_core_osabi_sniffer (bfd *abfd)
{
  if (strcmp (bfd_get_target (abfd), "netbsd-core") == 0)
    return GDB_OSABI_NETBSD_ELF;

  return GDB_OSABI_UNKNOWN;
}
\f

/* Provide a prototype to silence -Wmissing-prototypes.  */
void _initialize_alphanbsd_tdep (void);

void
_initialize_alphanbsd_tdep (void)
{
  /* BFD doesn't set a flavour for NetBSD style a.out core files.  */
  gdbarch_register_osabi_sniffer (bfd_arch_alpha, bfd_target_unknown_flavour,
                                  alphanbsd_core_osabi_sniffer);

  gdbarch_register_osabi (bfd_arch_alpha, 0, GDB_OSABI_NETBSD_ELF,
                          alphanbsd_init_abi);
}
Commit	Line	Data
	1	/* Target-dependent code for NetBSD/alpha.
	2
	3	Copyright (C) 2002-2016 Free Software Foundation, Inc.
	4
	5	Contributed by Wasabi Systems, Inc.
	6
	7	This file is part of GDB.
	8
	9	This program is free software; you can redistribute it and/or modify
	10	it under the terms of the GNU General Public License as published by
	11	the Free Software Foundation; either version 3 of the License, or
	12	(at your option) any later version.
	13
	14	This program is distributed in the hope that it will be useful,
	15	but WITHOUT ANY WARRANTY; without even the implied warranty of
	16	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	17	GNU General Public License for more details.
	18
	19	You should have received a copy of the GNU General Public License
	20	along with this program. If not, see <http://www.gnu.org/licenses/>. */
	21
	22	#include "defs.h"
	23	#include "frame.h"
	24	#include "gdbcore.h"
	25	#include "osabi.h"
	26	#include "regcache.h"
	27	#include "regset.h"
	28	#include "value.h"
	29
	30	#include "alpha-tdep.h"
	31	#include "alphabsd-tdep.h"
	32	#include "nbsd-tdep.h"
	33	#include "solib-svr4.h"
	34	#include "target.h"
	35
	36	/* Core file support. */
	37
	38	/* Even though NetBSD/alpha used ELF since day one, it used the
	39	traditional a.out-style core dump format before NetBSD 1.6. */
	40
	41	/* Sizeof `struct reg' in <machine/reg.h>. */
	42	#define ALPHANBSD_SIZEOF_GREGS (32 * 8)
	43
	44	/* Sizeof `struct fpreg' in <machine/reg.h. */
	45	#define ALPHANBSD_SIZEOF_FPREGS ((32 * 8) + 8)
	46
	47	/* Supply register REGNUM from the buffer specified by FPREGS and LEN
	48	in the floating-point register set REGSET to register cache
	49	REGCACHE. If REGNUM is -1, do this for all registers in REGSET. */
	50
	51	static void
	52	alphanbsd_supply_fpregset (const struct regset *regset,
	53	struct regcache *regcache,
	54	int regnum, const void *fpregs, size_t len)
	55	{
	56	const gdb_byte regs = (const gdb_byte ) fpregs;
	57	int i;
	58
	59	gdb_assert (len >= ALPHANBSD_SIZEOF_FPREGS);
	60
	61	for (i = ALPHA_FP0_REGNUM; i < ALPHA_FP0_REGNUM + 31; i++)
	62	{
	63	if (regnum == i \|\| regnum == -1)
	64	regcache_raw_supply (regcache, i, regs + (i - ALPHA_FP0_REGNUM) * 8);
	65	}
	66
	67	if (regnum == ALPHA_FPCR_REGNUM \|\| regnum == -1)
	68	regcache_raw_supply (regcache, ALPHA_FPCR_REGNUM, regs + 32 * 8);
	69	}
	70
	71	/* Supply register REGNUM from the buffer specified by GREGS and LEN
	72	in the general-purpose register set REGSET to register cache
	73	REGCACHE. If REGNUM is -1, do this for all registers in REGSET. */
	74
	75	static void
	76	alphanbsd_aout_supply_gregset (const struct regset *regset,
	77	struct regcache *regcache,
	78	int regnum, const void *gregs, size_t len)
	79	{
	80	const gdb_byte regs = (const gdb_byte ) gregs;
	81	int i;
	82
	83	/* Table to map a GDB register number to a trapframe register index. */
	84	static const int regmap[] =
	85	{
	86	0, 1, 2, 3,
	87	4, 5, 6, 7,
	88	8, 9, 10, 11,
	89	12, 13, 14, 15,
	90	30, 31, 32, 16,
	91	17, 18, 19, 20,
	92	21, 22, 23, 24,
	93	25, 29, 26
	94	};
	95
	96	gdb_assert (len >= ALPHANBSD_SIZEOF_GREGS);
	97
	98	for (i = 0; i < ARRAY_SIZE(regmap); i++)
	99	{
	100	if (regnum == i \|\| regnum == -1)
	101	regcache_raw_supply (regcache, i, regs + regmap[i] * 8);
	102	}
	103
	104	if (regnum == ALPHA_PC_REGNUM \|\| regnum == -1)
	105	regcache_raw_supply (regcache, ALPHA_PC_REGNUM, regs + 31 * 8);
	106
	107	if (len >= ALPHANBSD_SIZEOF_GREGS + ALPHANBSD_SIZEOF_FPREGS)
	108	{
	109	regs += ALPHANBSD_SIZEOF_GREGS;
	110	len -= ALPHANBSD_SIZEOF_GREGS;
	111	alphanbsd_supply_fpregset (regset, regcache, regnum, regs, len);
	112	}
	113	}
	114
	115	/* Supply register REGNUM from the buffer specified by GREGS and LEN
	116	in the general-purpose register set REGSET to register cache
	117	REGCACHE. If REGNUM is -1, do this for all registers in REGSET. */
	118
	119	static void
	120	alphanbsd_supply_gregset (const struct regset *regset,
	121	struct regcache *regcache,
	122	int regnum, const void *gregs, size_t len)
	123	{
	124	const gdb_byte regs = (const gdb_byte ) gregs;
	125	int i;
	126
	127	if (len >= ALPHANBSD_SIZEOF_GREGS + ALPHANBSD_SIZEOF_FPREGS)
	128	{
	129	alphanbsd_aout_supply_gregset (regset, regcache, regnum, gregs, len);
	130	return;
	131	}
	132
	133	for (i = 0; i < ALPHA_ZERO_REGNUM; i++)
	134	{
	135	if (regnum == i \|\| regnum == -1)
	136	regcache_raw_supply (regcache, i, regs + i * 8);
	137	}
	138
	139	if (regnum == ALPHA_PC_REGNUM \|\| regnum == -1)
	140	regcache_raw_supply (regcache, ALPHA_PC_REGNUM, regs + 31 * 8);
	141	}
	142
	143	/* NetBSD/alpha register sets. */
	144
	145	static const struct regset alphanbsd_gregset =
	146	{
	147	NULL,
	148	alphanbsd_supply_gregset,
	149	NULL,
	150	REGSET_VARIABLE_SIZE
	151	};
	152
	153	static const struct regset alphanbsd_fpregset =
	154	{
	155	NULL,
	156	alphanbsd_supply_fpregset
	157	};
	158
	159	/* Iterate over supported core file register note sections. */
	160
	161	void
	162	alphanbsd_iterate_over_regset_sections (struct gdbarch *gdbarch,
	163	iterate_over_regset_sections_cb *cb,
	164	void *cb_data,
	165	const struct regcache *regcache)
	166	{
	167	cb (".reg", ALPHANBSD_SIZEOF_GREGS, &alphanbsd_gregset, NULL, cb_data);
	168	cb (".reg2", ALPHANBSD_SIZEOF_FPREGS, &alphanbsd_fpregset, NULL, cb_data);
	169	}
	170	\f
	171
	172	/* Signal trampolines. */
	173
	174	/* Under NetBSD/alpha, signal handler invocations can be identified by the
	175	designated code sequence that is used to return from a signal handler.
	176	In particular, the return address of a signal handler points to the
	177	following code sequence:
	178
	179	ldq a0, 0(sp)
	180	lda sp, 16(sp)
	181	lda v0, 295(zero) # __sigreturn14
	182	call_pal callsys
	183
	184	Each instruction has a unique encoding, so we simply attempt to match
	185	the instruction the PC is pointing to with any of the above instructions.
	186	If there is a hit, we know the offset to the start of the designated
	187	sequence and can then check whether we really are executing in the
	188	signal trampoline. If not, -1 is returned, otherwise the offset from the
	189	start of the return sequence is returned. */
	190	static const gdb_byte sigtramp_retcode[] =
	191	{
	192	0x00, 0x00, 0x1e, 0xa6, /* ldq a0, 0(sp) */
	193	0x10, 0x00, 0xde, 0x23, /* lda sp, 16(sp) */
	194	0x27, 0x01, 0x1f, 0x20, /* lda v0, 295(zero) */
	195	0x83, 0x00, 0x00, 0x00, /* call_pal callsys */
	196	};
	197	#define RETCODE_NWORDS 4
	198	#define RETCODE_SIZE (RETCODE_NWORDS * 4)
	199
	200	static LONGEST
	201	alphanbsd_sigtramp_offset (struct gdbarch *gdbarch, CORE_ADDR pc)
	202	{
	203	gdb_byte ret[RETCODE_SIZE], w[4];
	204	LONGEST off;
	205	int i;
	206
	207	if (target_read_memory (pc, w, 4) != 0)
	208	return -1;
	209
	210	for (i = 0; i < RETCODE_NWORDS; i++)
	211	{
	212	if (memcmp (w, sigtramp_retcode + (i * 4), 4) == 0)
	213	break;
	214	}
	215	if (i == RETCODE_NWORDS)
	216	return (-1);
	217
	218	off = i * 4;
	219	pc -= off;
	220
	221	if (target_read_memory (pc, ret, sizeof (ret)) != 0)
	222	return -1;
	223
	224	if (memcmp (ret, sigtramp_retcode, RETCODE_SIZE) == 0)
	225	return off;
	226
	227	return -1;
	228	}
	229
	230	static int
	231	alphanbsd_pc_in_sigtramp (struct gdbarch *gdbarch,
	232	CORE_ADDR pc, const char *func_name)
	233	{
	234	return (nbsd_pc_in_sigtramp (pc, func_name)
	235	\|\| alphanbsd_sigtramp_offset (gdbarch, pc) >= 0);
	236	}
	237
	238	static CORE_ADDR
	239	alphanbsd_sigcontext_addr (struct frame_info *frame)
	240	{
	241	/* FIXME: This is not correct for all versions of NetBSD/alpha.
	242	We will probably need to disassemble the trampoline to figure
	243	out which trampoline frame type we have. */
	244	if (!get_next_frame (frame))
	245	return 0;
	246	return get_frame_base (get_next_frame (frame));
	247	}
	248	\f
	249
	250	static void
	251	alphanbsd_init_abi (struct gdbarch_info info,
	252	struct gdbarch *gdbarch)
	253	{
	254	struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
	255
	256	/* Hook into the DWARF CFI frame unwinder. */
	257	alpha_dwarf2_init_abi (info, gdbarch);
	258
	259	/* Hook into the MDEBUG frame unwinder. */
	260	alpha_mdebug_init_abi (info, gdbarch);
	261
	262	/* NetBSD/alpha does not provide single step support via ptrace(2); we
	263	must use software single-stepping. */
	264	set_gdbarch_software_single_step (gdbarch, alpha_software_single_step);
	265
	266	/* NetBSD/alpha has SVR4-style shared libraries. */
	267	set_solib_svr4_fetch_link_map_offsets
	268	(gdbarch, svr4_lp64_fetch_link_map_offsets);
	269
	270	tdep->dynamic_sigtramp_offset = alphanbsd_sigtramp_offset;
	271	tdep->pc_in_sigtramp = alphanbsd_pc_in_sigtramp;
	272	tdep->sigcontext_addr = alphanbsd_sigcontext_addr;
	273
	274	tdep->jb_pc = 2;
	275	tdep->jb_elt_size = 8;
	276
	277	set_gdbarch_iterate_over_regset_sections
	278	(gdbarch, alphanbsd_iterate_over_regset_sections);
	279	}
	280	\f
	281
	282	static enum gdb_osabi
	283	alphanbsd_core_osabi_sniffer (bfd *abfd)
	284	{
	285	if (strcmp (bfd_get_target (abfd), "netbsd-core") == 0)
	286	return GDB_OSABI_NETBSD_ELF;
	287
	288	return GDB_OSABI_UNKNOWN;
	289	}
	290	\f
	291
	292	/* Provide a prototype to silence -Wmissing-prototypes. */
	293	void _initialize_alphanbsd_tdep (void);
	294
	295	void
	296	_initialize_alphanbsd_tdep (void)
	297	{
	298	/* BFD doesn't set a flavour for NetBSD style a.out core files. */
	299	gdbarch_register_osabi_sniffer (bfd_arch_alpha, bfd_target_unknown_flavour,
	300	alphanbsd_core_osabi_sniffer);
	301
	302	gdbarch_register_osabi (bfd_arch_alpha, 0, GDB_OSABI_NETBSD_ELF,
	303	alphanbsd_init_abi);
	304	}