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

/* Target-dependent code for NetBSD/alpha.

   Copyright (C) 2002, 2003, 2004, 2006, 2007, 2008
   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 "gdb_assert.h"
#include "gdb_string.h"

#include "alpha-tdep.h"
#include "alphabsd-tdep.h"
#include "nbsd-tdep.h"
#include "solib-svr4.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 = 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_supply_gregset (const struct regset *regset,
			  struct regcache *regcache,
			  int regnum, const void *gregs, size_t len)
{
  const gdb_byte *regs = gregs;
  int i;

  gdb_assert (len >= ALPHANBSD_SIZEOF_GREGS);

  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);
}

/* 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 = 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);
    }
}

/* NetBSD/alpha register sets.  */

static struct regset alphanbsd_gregset =
{
  NULL,
  alphanbsd_supply_gregset
};

static struct regset alphanbsd_fpregset =
{
  NULL,
  alphanbsd_supply_fpregset
};

static struct regset alphanbsd_aout_gregset =
{
  NULL,
  alphanbsd_aout_supply_gregset
};

/* Return the appropriate register set for the core section identified
   by SECT_NAME and SECT_SIZE.  */

const struct regset *
alphanbsd_regset_from_core_section (struct gdbarch *gdbarch,
				    const char *sect_name, size_t sect_size)
{
  if (strcmp (sect_name, ".reg") == 0 && sect_size >= ALPHANBSD_SIZEOF_GREGS)
    {
      if (sect_size >= ALPHANBSD_SIZEOF_GREGS + ALPHANBSD_SIZEOF_FPREGS)
	return &alphanbsd_aout_gregset;
      else
	return &alphanbsd_gregset;
    }

  if (strcmp (sect_name, ".reg2") == 0 && sect_size >= ALPHANBSD_SIZEOF_FPREGS)
    return &alphanbsd_fpregset;

  return NULL;
}
\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 unsigned char 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 (CORE_ADDR pc)
{
  unsigned char ret[RETCODE_SIZE], w[4];
  LONGEST off;
  int i;

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

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

  return -1;
}

static int
alphanbsd_pc_in_sigtramp (CORE_ADDR pc, char *func_name)
{
  return (nbsd_pc_in_sigtramp (pc, func_name)
	  || alphanbsd_sigtramp_offset (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.  */
  return get_frame_base (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_regset_from_core_section
    (gdbarch, alphanbsd_regset_from_core_section);
}
\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, 2003, 2004, 2006, 2007, 2008
	4	Free Software Foundation, Inc.
	5
	6	Contributed by Wasabi Systems, Inc.
	7
	8	This file is part of GDB.
	9
	10	This program is free software; you can redistribute it and/or modify
	11	it under the terms of the GNU General Public License as published by
	12	the Free Software Foundation; either version 3 of the License, or
	13	(at your option) any later version.
	14
	15	This program is distributed in the hope that it will be useful,
	16	but WITHOUT ANY WARRANTY; without even the implied warranty of
	17	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	18	GNU General Public License for more details.
	19
	20	You should have received a copy of the GNU General Public License
	21	along with this program. If not, see <http://www.gnu.org/licenses/>. */
	22
	23	#include "defs.h"
	24	#include "frame.h"
	25	#include "gdbcore.h"
	26	#include "osabi.h"
	27	#include "regcache.h"
	28	#include "regset.h"
	29	#include "value.h"
	30
	31	#include "gdb_assert.h"
	32	#include "gdb_string.h"
	33
	34	#include "alpha-tdep.h"
	35	#include "alphabsd-tdep.h"
	36	#include "nbsd-tdep.h"
	37	#include "solib-svr4.h"
	38
	39	/* Core file support. */
	40
	41	/* Even though NetBSD/alpha used ELF since day one, it used the
	42	traditional a.out-style core dump format before NetBSD 1.6. */
	43
	44	/* Sizeof `struct reg' in <machine/reg.h>. */
	45	#define ALPHANBSD_SIZEOF_GREGS (32 * 8)
	46
	47	/* Sizeof `struct fpreg' in <machine/reg.h. */
	48	#define ALPHANBSD_SIZEOF_FPREGS ((32 * 8) + 8)
	49
	50	/* Supply register REGNUM from the buffer specified by FPREGS and LEN
	51	in the floating-point register set REGSET to register cache
	52	REGCACHE. If REGNUM is -1, do this for all registers in REGSET. */
	53
	54	static void
	55	alphanbsd_supply_fpregset (const struct regset *regset,
	56	struct regcache *regcache,
	57	int regnum, const void *fpregs, size_t len)
	58	{
	59	const gdb_byte *regs = fpregs;
	60	int i;
	61
	62	gdb_assert (len >= ALPHANBSD_SIZEOF_FPREGS);
	63
	64	for (i = ALPHA_FP0_REGNUM; i < ALPHA_FP0_REGNUM + 31; i++)
	65	{
	66	if (regnum == i \|\| regnum == -1)
	67	regcache_raw_supply (regcache, i, regs + (i - ALPHA_FP0_REGNUM) * 8);
	68	}
	69
	70	if (regnum == ALPHA_FPCR_REGNUM \|\| regnum == -1)
	71	regcache_raw_supply (regcache, ALPHA_FPCR_REGNUM, regs + 32 * 8);
	72	}
	73
	74	/* Supply register REGNUM from the buffer specified by GREGS and LEN
	75	in the general-purpose register set REGSET to register cache
	76	REGCACHE. If REGNUM is -1, do this for all registers in REGSET. */
	77
	78	static void
	79	alphanbsd_supply_gregset (const struct regset *regset,
	80	struct regcache *regcache,
	81	int regnum, const void *gregs, size_t len)
	82	{
	83	const gdb_byte *regs = gregs;
	84	int i;
	85
	86	gdb_assert (len >= ALPHANBSD_SIZEOF_GREGS);
	87
	88	for (i = 0; i < ALPHA_ZERO_REGNUM; i++)
	89	{
	90	if (regnum == i \|\| regnum == -1)
	91	regcache_raw_supply (regcache, i, regs + i * 8);
	92	}
	93
	94	if (regnum == ALPHA_PC_REGNUM \|\| regnum == -1)
	95	regcache_raw_supply (regcache, ALPHA_PC_REGNUM, regs + 31 * 8);
	96	}
	97
	98	/* Supply register REGNUM from the buffer specified by GREGS and LEN
	99	in the general-purpose register set REGSET to register cache
	100	REGCACHE. If REGNUM is -1, do this for all registers in REGSET. */
	101
	102	static void
	103	alphanbsd_aout_supply_gregset (const struct regset *regset,
	104	struct regcache *regcache,
	105	int regnum, const void *gregs, size_t len)
	106	{
	107	const gdb_byte *regs = gregs;
	108	int i;
	109
	110	/* Table to map a GDB register number to a trapframe register index. */
	111	static const int regmap[] =
	112	{
	113	0, 1, 2, 3,
	114	4, 5, 6, 7,
	115	8, 9, 10, 11,
	116	12, 13, 14, 15,
	117	30, 31, 32, 16,
	118	17, 18, 19, 20,
	119	21, 22, 23, 24,
	120	25, 29, 26
	121	};
	122
	123	gdb_assert (len >= ALPHANBSD_SIZEOF_GREGS);
	124
	125	for (i = 0; i < ARRAY_SIZE(regmap); i++)
	126	{
	127	if (regnum == i \|\| regnum == -1)
	128	regcache_raw_supply (regcache, i, regs + regmap[i] * 8);
	129	}
	130
	131	if (regnum == ALPHA_PC_REGNUM \|\| regnum == -1)
	132	regcache_raw_supply (regcache, ALPHA_PC_REGNUM, regs + 31 * 8);
	133
	134	if (len >= ALPHANBSD_SIZEOF_GREGS + ALPHANBSD_SIZEOF_FPREGS)
	135	{
	136	regs += ALPHANBSD_SIZEOF_GREGS;
	137	len -= ALPHANBSD_SIZEOF_GREGS;
	138	alphanbsd_supply_fpregset (regset, regcache, regnum, regs, len);
	139	}
	140	}
	141
	142	/* NetBSD/alpha register sets. */
	143
	144	static struct regset alphanbsd_gregset =
	145	{
	146	NULL,
	147	alphanbsd_supply_gregset
	148	};
	149
	150	static struct regset alphanbsd_fpregset =
	151	{
	152	NULL,
	153	alphanbsd_supply_fpregset
	154	};
	155
	156	static struct regset alphanbsd_aout_gregset =
	157	{
	158	NULL,
	159	alphanbsd_aout_supply_gregset
	160	};
	161
	162	/* Return the appropriate register set for the core section identified
	163	by SECT_NAME and SECT_SIZE. */
	164
	165	const struct regset *
	166	alphanbsd_regset_from_core_section (struct gdbarch *gdbarch,
	167	const char *sect_name, size_t sect_size)
	168	{
	169	if (strcmp (sect_name, ".reg") == 0 && sect_size >= ALPHANBSD_SIZEOF_GREGS)
	170	{
	171	if (sect_size >= ALPHANBSD_SIZEOF_GREGS + ALPHANBSD_SIZEOF_FPREGS)
	172	return &alphanbsd_aout_gregset;
	173	else
	174	return &alphanbsd_gregset;
	175	}
	176
	177	if (strcmp (sect_name, ".reg2") == 0 && sect_size >= ALPHANBSD_SIZEOF_FPREGS)
	178	return &alphanbsd_fpregset;
	179
	180	return NULL;
	181	}
	182	\f
	183
	184	/* Signal trampolines. */
	185
	186	/* Under NetBSD/alpha, signal handler invocations can be identified by the
	187	designated code sequence that is used to return from a signal handler.
	188	In particular, the return address of a signal handler points to the
	189	following code sequence:
	190
	191	ldq a0, 0(sp)
	192	lda sp, 16(sp)
	193	lda v0, 295(zero) # __sigreturn14
	194	call_pal callsys
	195
	196	Each instruction has a unique encoding, so we simply attempt to match
	197	the instruction the PC is pointing to with any of the above instructions.
	198	If there is a hit, we know the offset to the start of the designated
	199	sequence and can then check whether we really are executing in the
	200	signal trampoline. If not, -1 is returned, otherwise the offset from the
	201	start of the return sequence is returned. */
	202	static const unsigned char sigtramp_retcode[] =
	203	{
	204	0x00, 0x00, 0x1e, 0xa6, /* ldq a0, 0(sp) */
	205	0x10, 0x00, 0xde, 0x23, /* lda sp, 16(sp) */
	206	0x27, 0x01, 0x1f, 0x20, /* lda v0, 295(zero) */
	207	0x83, 0x00, 0x00, 0x00, /* call_pal callsys */
	208	};
	209	#define RETCODE_NWORDS 4
	210	#define RETCODE_SIZE (RETCODE_NWORDS * 4)
	211
	212	static LONGEST
	213	alphanbsd_sigtramp_offset (CORE_ADDR pc)
	214	{
	215	unsigned char ret[RETCODE_SIZE], w[4];
	216	LONGEST off;
	217	int i;
	218
	219	if (target_read_memory (pc, (char *) w, 4) != 0)
	220	return -1;
	221
	222	for (i = 0; i < RETCODE_NWORDS; i++)
	223	{
	224	if (memcmp (w, sigtramp_retcode + (i * 4), 4) == 0)
	225	break;
	226	}
	227	if (i == RETCODE_NWORDS)
	228	return (-1);
	229
	230	off = i * 4;
	231	pc -= off;
	232
	233	if (target_read_memory (pc, (char *) ret, sizeof (ret)) != 0)
	234	return -1;
	235
	236	if (memcmp (ret, sigtramp_retcode, RETCODE_SIZE) == 0)
	237	return off;
	238
	239	return -1;
	240	}
	241
	242	static int
	243	alphanbsd_pc_in_sigtramp (CORE_ADDR pc, char *func_name)
	244	{
	245	return (nbsd_pc_in_sigtramp (pc, func_name)
	246	\|\| alphanbsd_sigtramp_offset (pc) >= 0);
	247	}
	248
	249	static CORE_ADDR
	250	alphanbsd_sigcontext_addr (struct frame_info *frame)
	251	{
	252	/* FIXME: This is not correct for all versions of NetBSD/alpha.
	253	We will probably need to disassemble the trampoline to figure
	254	out which trampoline frame type we have. */
	255	return get_frame_base (frame);
	256	}
	257	\f
	258
	259	static void
	260	alphanbsd_init_abi (struct gdbarch_info info,
	261	struct gdbarch *gdbarch)
	262	{
	263	struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
	264
	265	/* Hook into the DWARF CFI frame unwinder. */
	266	alpha_dwarf2_init_abi (info, gdbarch);
	267
	268	/* Hook into the MDEBUG frame unwinder. */
	269	alpha_mdebug_init_abi (info, gdbarch);
	270
	271	/* NetBSD/alpha does not provide single step support via ptrace(2); we
	272	must use software single-stepping. */
	273	set_gdbarch_software_single_step (gdbarch, alpha_software_single_step);
	274
	275	/* NetBSD/alpha has SVR4-style shared libraries. */
	276	set_solib_svr4_fetch_link_map_offsets
	277	(gdbarch, svr4_lp64_fetch_link_map_offsets);
	278
	279	tdep->dynamic_sigtramp_offset = alphanbsd_sigtramp_offset;
	280	tdep->pc_in_sigtramp = alphanbsd_pc_in_sigtramp;
	281	tdep->sigcontext_addr = alphanbsd_sigcontext_addr;
	282
	283	tdep->jb_pc = 2;
	284	tdep->jb_elt_size = 8;
	285
	286	set_gdbarch_regset_from_core_section
	287	(gdbarch, alphanbsd_regset_from_core_section);
	288	}
	289	\f
	290
	291	static enum gdb_osabi
	292	alphanbsd_core_osabi_sniffer (bfd *abfd)
	293	{
	294	if (strcmp (bfd_get_target (abfd), "netbsd-core") == 0)
	295	return GDB_OSABI_NETBSD_ELF;
	296
	297	return GDB_OSABI_UNKNOWN;
	298	}
	299	\f
	300
	301	/* Provide a prototype to silence -Wmissing-prototypes. */
	302	void _initialize_alphanbsd_tdep (void);
	303
	304	void
	305	_initialize_alphanbsd_tdep (void)
	306	{
	307	/* BFD doesn't set a flavour for NetBSD style a.out core files. */
	308	gdbarch_register_osabi_sniffer (bfd_arch_alpha, bfd_target_unknown_flavour,
	309	alphanbsd_core_osabi_sniffer);
	310
	311	gdbarch_register_osabi (bfd_arch_alpha, 0, GDB_OSABI_NETBSD_ELF,
	312	alphanbsd_init_abi);
	313	}