[deliverable/binutils-gdb.git] / gdb / amd64obsd-tdep.c

/* Target-dependent code for OpenBSD/amd64.

   Copyright 2003, 2004 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 2 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, write to the Free Software
   Foundation, Inc., 59 Temple Place - Suite 330,
   Boston, MA 02111-1307, USA.  */

#include "defs.h"
#include "frame.h"
#include "gdbcore.h"
#include "symtab.h"
#include "objfiles.h"
#include "osabi.h"
#include "regset.h"
#include "target.h"

#include "gdb_assert.h"
#include "gdb_string.h"

#include "amd64-tdep.h"
#include "i387-tdep.h"
#include "solib-svr4.h"

/* Support for core dumps.  */

static void
amd64obsd_supply_regset (const struct regset *regset,
			 struct regcache *regcache, int regnum,
			 const void *regs, size_t len)
{
  const struct gdbarch_tdep *tdep = gdbarch_tdep (regset->arch);

  gdb_assert (len >= tdep->sizeof_gregset + I387_SIZEOF_FXSAVE);

  i386_supply_gregset (regset, regcache, regnum, regs, tdep->sizeof_gregset);
  amd64_supply_fxsave (regcache, regnum, (char *)regs + tdep->sizeof_gregset);
}

static const struct regset *
amd64obsd_regset_from_core_section (struct gdbarch *gdbarch,
				    const char *sect_name, size_t sect_size)
{
  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);

  /* OpenBSD core dumps don't use seperate register sets for the
     general-purpose and floating-point registers.  */

  if (strcmp (sect_name, ".reg") == 0
      && sect_size >= tdep->sizeof_gregset + I387_SIZEOF_FXSAVE)
    {
      if (tdep->gregset == NULL)
        tdep->gregset = regset_alloc (gdbarch, amd64obsd_supply_regset, NULL);
      return tdep->gregset;
    }

  return NULL;
}
\f

/* Support for signal handlers.  */

/* Default page size.  */
static const int amd64obsd_page_size = 4096;

/* Return whether the frame preceding NEXT_FRAME corresponds to an
   OpenBSD sigtramp routine.  */

static int
amd64obsd_sigtramp_p (struct frame_info *next_frame)
{
  CORE_ADDR pc = frame_pc_unwind (next_frame);
  CORE_ADDR start_pc = (pc & ~(amd64obsd_page_size - 1));
  const char sigreturn[] =
  {
    0x48, 0xc7, 0xc0,
    0x67, 0x00, 0x00, 0x00,	/* movq $SYS_sigreturn, %rax */
    0xcd, 0x80			/* int $0x80 */
  };
  char *name, *buf;

  /* If the function has a valid symbol name, it isn't a
     trampoline.  */
  find_pc_partial_function (pc, &name, NULL, NULL);
  if (name != NULL)
    return 0;

  /* If the function lives in a valid section (even without a starting
     point) it isn't a trampoline.  */
  if (find_pc_section (pc) != NULL)
    return 0;

  /* If we can't read the instructions at START_PC, return zero.  */
  buf = alloca ((sizeof sigreturn) + 1);
  if (target_read_memory (start_pc + 6, buf, (sizeof sigreturn) + 1))
    return 0;

  /* Check for sigreturn(2).  Depending on how the assembler encoded
     the `movq %rsp, %rdi' instruction, the code starts at offset 6 or
     7.  */
  if (memcmp (buf, sigreturn, sizeof sigreturn)
      && memcpy (buf + 1, sigreturn, sizeof sigreturn))
    return 0;

  return 1;
}

/* Assuming NEXT_FRAME is for a frame following a BSD sigtramp
   routine, return the address of the associated sigcontext structure.  */

static CORE_ADDR
amd64obsd_sigcontext_addr (struct frame_info *next_frame)
{
  CORE_ADDR pc = frame_pc_unwind (next_frame);
  ULONGEST offset = (pc & (amd64obsd_page_size - 1));

  /* The %rsp register points at `struct sigcontext' upon entry of a
     signal trampoline.  The relevant part of the trampoline is

        call    *%rax
        movq    %rsp, %rdi
        pushq   %rdi
        movq    $SYS_sigreturn,%rax
        int     $0x80

     (see /usr/src/sys/arch/amd64/amd64/locore.S).  The `pushq'
     instruction clobbers %rsp, but its value is saved in `%rdi'.  */

  if (offset > 5)
    return frame_unwind_register_unsigned (next_frame, AMD64_RDI_REGNUM);
  else
    return frame_unwind_register_unsigned (next_frame, AMD64_RSP_REGNUM);
}
\f
/* OpenBSD 3.5 or later.  */

/* Mapping between the general-purpose registers in `struct reg'
   format and GDB's register cache layout.  */

/* From <machine/reg.h>.  */
int amd64obsd_r_reg_offset[] =
{
  14 * 8,			/* %rax */
  13 * 8,			/* %rbx */
  3 * 8,			/* %rcx */
  2 * 8,			/* %rdx */
  1 * 8,			/* %rsi */
  0 * 8,			/* %rdi */
  12 * 8,			/* %rbp */
  15 * 8,			/* %rsp */
  4 * 8,			/* %r8 .. */
  5 * 8,
  6 * 8,
  7 * 8,
  8 * 8,
  9 * 8,
  10 * 8,
  11 * 8,			/* ... %r15 */
  16 * 8,			/* %rip */
  17 * 8,			/* %eflags */
  18 * 8,			/* %cs */
  19 * 8,			/* %ss */
  20 * 8,			/* %ds */
  21 * 8,			/* %es */
  22 * 8,			/* %fs */
  23 * 8			/* %gs */
};

/* From <machine/signal.h>.  */
static int amd64obsd_sc_reg_offset[] =
{
  14 * 8,			/* %rax */
  13 * 8,			/* %rbx */
  3 * 8,			/* %rcx */
  2 * 8,			/* %rdx */
  1 * 8,			/* %rsi */
  0 * 8,			/* %rdi */
  12 * 8,			/* %rbp */
  24 * 8,			/* %rsp */
  4 * 8,			/* %r8 ... */
  5 * 8,
  6 * 8,
  7 * 8,
  8 * 8,
  9 * 8,
  10 * 8,
  11 * 8,			/* ... %r15 */
  21 * 8,			/* %rip */
  23 * 8,			/* %eflags */
  22 * 8,			/* %cs */
  25 * 8,			/* %ss */
  18 * 8,			/* %ds */
  17 * 8,			/* %es */
  16 * 8,			/* %fs */
  15 * 8			/* %gs */
};

static void
amd64obsd_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
{
  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);

  amd64_init_abi (info, gdbarch);

  /* Initialize general-purpose register set details.  */
  tdep->gregset_reg_offset = amd64obsd_r_reg_offset;
  tdep->gregset_num_regs = ARRAY_SIZE (amd64obsd_r_reg_offset);
  tdep->sizeof_gregset = 24 * 8;

  set_gdbarch_regset_from_core_section (gdbarch,
					amd64obsd_regset_from_core_section);

  tdep->jb_pc_offset = 7 * 8;

  tdep->sigtramp_p = amd64obsd_sigtramp_p;
  tdep->sigcontext_addr = amd64obsd_sigcontext_addr;
  tdep->sc_reg_offset = amd64obsd_sc_reg_offset;
  tdep->sc_num_regs = ARRAY_SIZE (amd64obsd_sc_reg_offset);

  /* OpenBSD uses SVR4-style shared libraries.  */
  set_solib_svr4_fetch_link_map_offsets
    (gdbarch, svr4_lp64_fetch_link_map_offsets);
}
\f

/* Provide a prototype to silence -Wmissing-prototypes.  */
void _initialize_amd64obsd_tdep (void);

void
_initialize_amd64obsd_tdep (void)
{
  /* The OpenBSD/amd64 native dependent code makes this assumption.  */
  gdb_assert (ARRAY_SIZE (amd64obsd_r_reg_offset) == AMD64_NUM_GREGS);

  gdbarch_register_osabi (bfd_arch_i386, bfd_mach_x86_64,
			  GDB_OSABI_OPENBSD_ELF, amd64obsd_init_abi);

  /* OpenBSD uses traditional (a.out) NetBSD-style core dumps.  */
  gdbarch_register_osabi (bfd_arch_i386, bfd_mach_x86_64,
			  GDB_OSABI_NETBSD_AOUT, amd64obsd_init_abi);
}
Commit	Line	Data
	1	/* Target-dependent code for OpenBSD/amd64.
	2
	3	Copyright 2003, 2004 Free Software Foundation, Inc.
	4
	5	This file is part of GDB.
	6
	7	This program is free software; you can redistribute it and/or modify
	8	it under the terms of the GNU General Public License as published by
	9	the Free Software Foundation; either version 2 of the License, or
	10	(at your option) any later version.
	11
	12	This program is distributed in the hope that it will be useful,
	13	but WITHOUT ANY WARRANTY; without even the implied warranty of
	14	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	15	GNU General Public License for more details.
	16
	17	You should have received a copy of the GNU General Public License
	18	along with this program; if not, write to the Free Software
	19	Foundation, Inc., 59 Temple Place - Suite 330,
	20	Boston, MA 02111-1307, USA. */
	21
	22	#include "defs.h"
	23	#include "frame.h"
	24	#include "gdbcore.h"
	25	#include "symtab.h"
	26	#include "objfiles.h"
	27	#include "osabi.h"
	28	#include "regset.h"
	29	#include "target.h"
	30
	31	#include "gdb_assert.h"
	32	#include "gdb_string.h"
	33
	34	#include "amd64-tdep.h"
	35	#include "i387-tdep.h"
	36	#include "solib-svr4.h"
	37
	38	/* Support for core dumps. */
	39
	40	static void
	41	amd64obsd_supply_regset (const struct regset *regset,
	42	struct regcache *regcache, int regnum,
	43	const void *regs, size_t len)
	44	{
	45	const struct gdbarch_tdep *tdep = gdbarch_tdep (regset->arch);
	46
	47	gdb_assert (len >= tdep->sizeof_gregset + I387_SIZEOF_FXSAVE);
	48
	49	i386_supply_gregset (regset, regcache, regnum, regs, tdep->sizeof_gregset);
	50	amd64_supply_fxsave (regcache, regnum, (char *)regs + tdep->sizeof_gregset);
	51	}
	52
	53	static const struct regset *
	54	amd64obsd_regset_from_core_section (struct gdbarch *gdbarch,
	55	const char *sect_name, size_t sect_size)
	56	{
	57	struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
	58
	59	/* OpenBSD core dumps don't use seperate register sets for the
	60	general-purpose and floating-point registers. */
	61
	62	if (strcmp (sect_name, ".reg") == 0
	63	&& sect_size >= tdep->sizeof_gregset + I387_SIZEOF_FXSAVE)
	64	{
	65	if (tdep->gregset == NULL)
	66	tdep->gregset = regset_alloc (gdbarch, amd64obsd_supply_regset, NULL);
	67	return tdep->gregset;
	68	}
	69
	70	return NULL;
	71	}
	72	\f
	73
	74	/* Support for signal handlers. */
	75
	76	/* Default page size. */
	77	static const int amd64obsd_page_size = 4096;
	78
	79	/* Return whether the frame preceding NEXT_FRAME corresponds to an
	80	OpenBSD sigtramp routine. */
	81
	82	static int
	83	amd64obsd_sigtramp_p (struct frame_info *next_frame)
	84	{
	85	CORE_ADDR pc = frame_pc_unwind (next_frame);
	86	CORE_ADDR start_pc = (pc & ~(amd64obsd_page_size - 1));
	87	const char sigreturn[] =
	88	{
	89	0x48, 0xc7, 0xc0,
	90	0x67, 0x00, 0x00, 0x00, /* movq $SYS_sigreturn, %rax */
	91	0xcd, 0x80 /* int $0x80 */
	92	};
	93	char name, buf;
	94
	95	/* If the function has a valid symbol name, it isn't a
	96	trampoline. */
	97	find_pc_partial_function (pc, &name, NULL, NULL);
	98	if (name != NULL)
	99	return 0;
	100
	101	/* If the function lives in a valid section (even without a starting
	102	point) it isn't a trampoline. */
	103	if (find_pc_section (pc) != NULL)
	104	return 0;
	105
	106	/* If we can't read the instructions at START_PC, return zero. */
	107	buf = alloca ((sizeof sigreturn) + 1);
	108	if (target_read_memory (start_pc + 6, buf, (sizeof sigreturn) + 1))
	109	return 0;
	110
	111	/* Check for sigreturn(2). Depending on how the assembler encoded
	112	the `movq %rsp, %rdi' instruction, the code starts at offset 6 or
	113	7. */
	114	if (memcmp (buf, sigreturn, sizeof sigreturn)
	115	&& memcpy (buf + 1, sigreturn, sizeof sigreturn))
	116	return 0;
	117
	118	return 1;
	119	}
	120
	121	/* Assuming NEXT_FRAME is for a frame following a BSD sigtramp
	122	routine, return the address of the associated sigcontext structure. */
	123
	124	static CORE_ADDR
	125	amd64obsd_sigcontext_addr (struct frame_info *next_frame)
	126	{
	127	CORE_ADDR pc = frame_pc_unwind (next_frame);
	128	ULONGEST offset = (pc & (amd64obsd_page_size - 1));
	129
	130	/* The %rsp register points at `struct sigcontext' upon entry of a
	131	signal trampoline. The relevant part of the trampoline is
	132
	133	call *%rax
	134	movq %rsp, %rdi
	135	pushq %rdi
	136	movq $SYS_sigreturn,%rax
	137	int $0x80
	138
	139	(see /usr/src/sys/arch/amd64/amd64/locore.S). The `pushq'
	140	instruction clobbers %rsp, but its value is saved in `%rdi'. */
	141
	142	if (offset > 5)
	143	return frame_unwind_register_unsigned (next_frame, AMD64_RDI_REGNUM);
	144	else
	145	return frame_unwind_register_unsigned (next_frame, AMD64_RSP_REGNUM);
	146	}
	147	\f
	148	/* OpenBSD 3.5 or later. */
	149
	150	/* Mapping between the general-purpose registers in `struct reg'
	151	format and GDB's register cache layout. */
	152
	153	/* From <machine/reg.h>. */
	154	int amd64obsd_r_reg_offset[] =
	155	{
	156	14 * 8, /* %rax */
	157	13 * 8, /* %rbx */
	158	3 * 8, /* %rcx */
	159	2 * 8, /* %rdx */
	160	1 * 8, /* %rsi */
	161	0 * 8, /* %rdi */
	162	12 * 8, /* %rbp */
	163	15 * 8, /* %rsp */
	164	4 * 8, /* %r8 .. */
	165	5 * 8,
	166	6 * 8,
	167	7 * 8,
	168	8 * 8,
	169	9 * 8,
	170	10 * 8,
	171	11 * 8, /* ... %r15 */
	172	16 * 8, /* %rip */
	173	17 * 8, /* %eflags */
	174	18 * 8, /* %cs */
	175	19 * 8, /* %ss */
	176	20 * 8, /* %ds */
	177	21 * 8, /* %es */
	178	22 * 8, /* %fs */
	179	23 * 8 /* %gs */
	180	};
	181
	182	/* From <machine/signal.h>. */
	183	static int amd64obsd_sc_reg_offset[] =
	184	{
	185	14 * 8, /* %rax */
	186	13 * 8, /* %rbx */
	187	3 * 8, /* %rcx */
	188	2 * 8, /* %rdx */
	189	1 * 8, /* %rsi */
	190	0 * 8, /* %rdi */
	191	12 * 8, /* %rbp */
	192	24 * 8, /* %rsp */
	193	4 * 8, /* %r8 ... */
	194	5 * 8,
	195	6 * 8,
	196	7 * 8,
	197	8 * 8,
	198	9 * 8,
	199	10 * 8,
	200	11 * 8, /* ... %r15 */
	201	21 * 8, /* %rip */
	202	23 * 8, /* %eflags */
	203	22 * 8, /* %cs */
	204	25 * 8, /* %ss */
	205	18 * 8, /* %ds */
	206	17 * 8, /* %es */
	207	16 * 8, /* %fs */
	208	15 * 8 /* %gs */
	209	};
	210
	211	static void
	212	amd64obsd_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
	213	{
	214	struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
	215
	216	amd64_init_abi (info, gdbarch);
	217
	218	/* Initialize general-purpose register set details. */
	219	tdep->gregset_reg_offset = amd64obsd_r_reg_offset;
	220	tdep->gregset_num_regs = ARRAY_SIZE (amd64obsd_r_reg_offset);
	221	tdep->sizeof_gregset = 24 * 8;
	222
	223	set_gdbarch_regset_from_core_section (gdbarch,
	224	amd64obsd_regset_from_core_section);
	225
	226	tdep->jb_pc_offset = 7 * 8;
	227
	228	tdep->sigtramp_p = amd64obsd_sigtramp_p;
	229	tdep->sigcontext_addr = amd64obsd_sigcontext_addr;
	230	tdep->sc_reg_offset = amd64obsd_sc_reg_offset;
	231	tdep->sc_num_regs = ARRAY_SIZE (amd64obsd_sc_reg_offset);
	232
	233	/* OpenBSD uses SVR4-style shared libraries. */
	234	set_solib_svr4_fetch_link_map_offsets
	235	(gdbarch, svr4_lp64_fetch_link_map_offsets);
	236	}
	237	\f
	238
	239	/* Provide a prototype to silence -Wmissing-prototypes. */
	240	void _initialize_amd64obsd_tdep (void);
	241
	242	void
	243	_initialize_amd64obsd_tdep (void)
	244	{
	245	/* The OpenBSD/amd64 native dependent code makes this assumption. */
	246	gdb_assert (ARRAY_SIZE (amd64obsd_r_reg_offset) == AMD64_NUM_GREGS);
	247
	248	gdbarch_register_osabi (bfd_arch_i386, bfd_mach_x86_64,
	249	GDB_OSABI_OPENBSD_ELF, amd64obsd_init_abi);
	250
	251	/* OpenBSD uses traditional (a.out) NetBSD-style core dumps. */
	252	gdbarch_register_osabi (bfd_arch_i386, bfd_mach_x86_64,
	253	GDB_OSABI_NETBSD_AOUT, amd64obsd_init_abi);
	254	}