[deliverable/binutils-gdb.git] / gdb / amd64-linux-tdep.c

/* Target-dependent code for GNU/Linux x86-64.

   Copyright 2001, 2003, 2004 Free Software Foundation, Inc.
   Contributed by Jiri Smid, SuSE Labs.

   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 "regcache.h"
#include "osabi.h"

#include "gdb_string.h"

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

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

/* From <sys/reg.h>.  */
static int amd64_linux_gregset_reg_offset[] =
{
  10 * 8,			/* %rax */
  5 * 8,			/* %rbx */
  11 * 8,			/* %rcx */
  12 * 8,			/* %rdx */
  13 * 8,			/* %rsi */
  14 * 8,			/* %rdi */
  4 * 8,			/* %rbp */
  19 * 8,			/* %rsp */
  9 * 8,			/* %r8 ... */
  8 * 8,
  7 * 8,
  6 * 8,
  3 * 8,
  2 * 8,
  1 * 8,
  0 * 8,			/* ... %r15 */
  16 * 8,			/* %rip */
  18 * 8,			/* %eflags */
  17 * 8,			/* %cs */
  20 * 8,			/* %ss */
  23 * 8,			/* %ds */
  24 * 8,			/* %es */
  25 * 8,			/* %fs */
  26 * 8			/* %gs */
};
\f

/* Support for signal handlers.  */

#define LINUX_SIGTRAMP_INSN0	0x48	/* mov $NNNNNNNN, %rax */
#define LINUX_SIGTRAMP_OFFSET0	0
#define LINUX_SIGTRAMP_INSN1	0x0f	/* syscall */
#define LINUX_SIGTRAMP_OFFSET1	7

static const unsigned char linux_sigtramp_code[] =
{
  /* mov $__NR_rt_sigreturn, %rax */
  LINUX_SIGTRAMP_INSN0, 0xc7, 0xc0, 0x0f, 0x00, 0x00, 0x00,
  /* syscall */
  LINUX_SIGTRAMP_INSN1, 0x05
};

#define LINUX_SIGTRAMP_LEN (sizeof linux_sigtramp_code)

/* If PC is in a sigtramp routine, return the address of the start of
   the routine.  Otherwise, return 0.  */

static CORE_ADDR
amd64_linux_sigtramp_start (CORE_ADDR pc)
{
  unsigned char buf[LINUX_SIGTRAMP_LEN];

  /* We only recognize a signal trampoline if PC is at the start of
     one of the two instructions.  We optimize for finding the PC at
     the start, as will be the case when the trampoline is not the
     first frame on the stack.  We assume that in the case where the
     PC is not at the start of the instruction sequence, there will be
     a few trailing readable bytes on the stack.  */

  if (read_memory_nobpt (pc, (char *) buf, LINUX_SIGTRAMP_LEN) != 0)
    return 0;

  if (buf[0] != LINUX_SIGTRAMP_INSN0)
    {
      if (buf[0] != LINUX_SIGTRAMP_INSN1)
	return 0;

      pc -= LINUX_SIGTRAMP_OFFSET1;

      if (read_memory_nobpt (pc, (char *) buf, LINUX_SIGTRAMP_LEN) != 0)
	return 0;
    }

  if (memcmp (buf, linux_sigtramp_code, LINUX_SIGTRAMP_LEN) != 0)
    return 0;

  return pc;
}

/* Return whether PC is in a GNU/Linux sigtramp routine.  */

static int
amd64_linux_pc_in_sigtramp (CORE_ADDR pc, char *name)
{
  /* If we have NAME, we can optimize the search.  The trampoline is
     named __restore_rt.  However, it isn't dynamically exported from
     the shared C library, so the trampoline may appear to be part of
     the preceding function.  This should always be sigaction,
     __sigaction, or __libc_sigaction (all aliases to the same
     function).  */
  if (name == NULL || strstr (name, "sigaction") != NULL)
    return (amd64_linux_sigtramp_start (pc) != 0);

  return (strcmp ("__restore_rt", name) == 0);
}

/* Offset to struct sigcontext in ucontext, from <asm/ucontext.h>.  */
#define AMD64_LINUX_UCONTEXT_SIGCONTEXT_OFFSET 40

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

static CORE_ADDR
amd64_linux_sigcontext_addr (struct frame_info *next_frame)
{
  CORE_ADDR sp;
  char buf[8];

  frame_unwind_register (next_frame, SP_REGNUM, buf);
  sp = extract_unsigned_integer (buf, 8);

  /* The sigcontext structure is part of the user context.  A pointer
     to the user context is passed as the third argument to the signal
     handler, i.e. in %rdx.  Unfortunately %rdx isn't preserved across
     function calls so we can't use it.  Fortunately the user context
     is part of the signal frame and the unwound %rsp directly points
     at it.  */
  return sp + AMD64_LINUX_UCONTEXT_SIGCONTEXT_OFFSET;
}
\f

/* From <asm/sigcontext.h>.  */
static int amd64_linux_sc_reg_offset[] =
{
  13 * 8,			/* %rax */
  11 * 8,			/* %rbx */
  14 * 8,			/* %rcx */
  12 * 8,			/* %rdx */
  9 * 8,			/* %rsi */
  8 * 8,			/* %rdi */
  10 * 8,			/* %rbp */
  15 * 8,			/* %rsp */
  0 * 8,			/* %r8 */
  1 * 8,			/* %r9 */
  2 * 8,			/* %r10 */
  3 * 8,			/* %r11 */
  4 * 8,			/* %r12 */
  5 * 8,			/* %r13 */
  6 * 8,			/* %r14 */
  7 * 8,			/* %r15 */
  16 * 8,			/* %rip */
  17 * 8,			/* %eflags */

  /* FIXME: kettenis/2002030531: The registers %cs, %fs and %gs are
     available in `struct sigcontext'.  However, they only occupy two
     bytes instead of four, which makes using them here rather
     difficult.  Leave them out for now.  */
  -1,				/* %cs */
  -1,				/* %ss */
  -1,				/* %ds */
  -1,				/* %es */
  -1,				/* %fs */
  -1				/* %gs */
};

static void
amd64_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
{
  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);

  tdep->gregset_reg_offset = amd64_linux_gregset_reg_offset;
  tdep->gregset_num_regs = ARRAY_SIZE (amd64_linux_gregset_reg_offset);
  tdep->sizeof_gregset = 27 * 8;

  amd64_init_abi (info, gdbarch);

  set_gdbarch_deprecated_pc_in_sigtramp (gdbarch, amd64_linux_pc_in_sigtramp);
  tdep->sigcontext_addr = amd64_linux_sigcontext_addr;
  tdep->sc_reg_offset = amd64_linux_sc_reg_offset;
  tdep->sc_num_regs = ARRAY_SIZE (amd64_linux_sc_reg_offset);

  /* GNU/Linux 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.  */
extern void _initialize_amd64_linux_tdep (void);

void
_initialize_amd64_linux_tdep (void)
{
  gdbarch_register_osabi (bfd_arch_i386, bfd_mach_x86_64,
			  GDB_OSABI_LINUX, amd64_linux_init_abi);
}
Commit	Line	Data
51433e4b	1	/* Target-dependent code for GNU/Linux x86-64.
a4b6fc86	2
af233647	3	Copyright 2001, 2003, 2004 Free Software Foundation, Inc.
53e95fcf JS	4	Contributed by Jiri Smid, SuSE Labs.
	5
	6	This file is part of GDB.
	7
	8	This program is free software; you can redistribute it and/or modify
	9	it under the terms of the GNU General Public License as published by
	10	the Free Software Foundation; either version 2 of the License, or
	11	(at your option) any later version.
	12
	13	This program is distributed in the hope that it will be useful,
	14	but WITHOUT ANY WARRANTY; without even the implied warranty of
	15	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	16	GNU General Public License for more details.
	17
	18	You should have received a copy of the GNU General Public License
	19	along with this program; if not, write to the Free Software
	20	Foundation, Inc., 59 Temple Place - Suite 330,
	21	Boston, MA 02111-1307, USA. */
	22
	23	#include "defs.h"
187e21d1	24	#include "frame.h"
53e95fcf JS	25	#include "gdbcore.h"
53e95fcf JS	26	#include "regcache.h"
84dc46cb	27	#include "osabi.h"
53e95fcf	28
c4f35dd8	29	#include "gdb_string.h"
53e95fcf	30
9c1488cb	31	#include "amd64-tdep.h"
187e21d1	32	#include "solib-svr4.h"
eba29c8c ML	33
eba29c8c ML	34	/* Mapping between the general-purpose registers in `struct user'
187e21d1	35	format and GDB's register cache layout. */
eba29c8c	36
187e21d1 MK	37	/* From <sys/reg.h>. */
187e21d1 MK	38	static int amd64_linux_gregset_reg_offset[] =
eba29c8c	39	{
187e21d1 MK	40	10 * 8, /* %rax */
	41	5 * 8, /* %rbx */
	42	11 * 8, /* %rcx */
	43	12 * 8, /* %rdx */
	44	13 * 8, /* %rsi */
	45	14 * 8, /* %rdi */
	46	4 * 8, /* %rbp */
	47	19 * 8, /* %rsp */
	48	9 * 8, /* %r8 ... */
	49	8 * 8,
	50	7 * 8,
	51	6 * 8,
	52	3 * 8,
	53	2 * 8,
	54	1 * 8,
	55	0 * 8, /* ... %r15 */
	56	16 * 8, /* %rip */
	57	18 * 8, /* %eflags */
	58	17 * 8, /* %cs */
	59	20 * 8, /* %ss */
	60	23 * 8, /* %ds */
	61	24 * 8, /* %es */
	62	25 * 8, /* %fs */
	63	26 * 8 /* %gs */
eba29c8c	64	};
187e21d1	65	\f
eba29c8c	66
187e21d1	67	/* Support for signal handlers. */
c4f35dd8 MK	68
	69	#define LINUX_SIGTRAMP_INSN0 0x48 /* mov $NNNNNNNN, %rax */
	70	#define LINUX_SIGTRAMP_OFFSET0 0
	71	#define LINUX_SIGTRAMP_INSN1 0x0f /* syscall */
	72	#define LINUX_SIGTRAMP_OFFSET1 7
	73
	74	static const unsigned char linux_sigtramp_code[] =
	75	{
	76	/* mov $__NR_rt_sigreturn, %rax */
baed091b ML	77	LINUX_SIGTRAMP_INSN0, 0xc7, 0xc0, 0x0f, 0x00, 0x00, 0x00,
	78	/* syscall */
	79	LINUX_SIGTRAMP_INSN1, 0x05
53e95fcf JS	80	};
	81
	82	#define LINUX_SIGTRAMP_LEN (sizeof linux_sigtramp_code)
	83
	84	/* If PC is in a sigtramp routine, return the address of the start of
	85	the routine. Otherwise, return 0. */
	86
	87	static CORE_ADDR
51433e4b	88	amd64_linux_sigtramp_start (CORE_ADDR pc)
53e95fcf JS	89	{
53e95fcf JS	90	unsigned char buf[LINUX_SIGTRAMP_LEN];
c4f35dd8 MK	91
	92	/* We only recognize a signal trampoline if PC is at the start of
	93	one of the two instructions. We optimize for finding the PC at
	94	the start, as will be the case when the trampoline is not the
	95	first frame on the stack. We assume that in the case where the
	96	PC is not at the start of the instruction sequence, there will be
	97	a few trailing readable bytes on the stack. */
	98
53e95fcf JS	99	if (read_memory_nobpt (pc, (char *) buf, LINUX_SIGTRAMP_LEN) != 0)
	100	return 0;
	101
	102	if (buf[0] != LINUX_SIGTRAMP_INSN0)
	103	{
	104	if (buf[0] != LINUX_SIGTRAMP_INSN1)
	105	return 0;
	106
	107	pc -= LINUX_SIGTRAMP_OFFSET1;
	108
	109	if (read_memory_nobpt (pc, (char *) buf, LINUX_SIGTRAMP_LEN) != 0)
	110	return 0;
	111	}
	112
	113	if (memcmp (buf, linux_sigtramp_code, LINUX_SIGTRAMP_LEN) != 0)
	114	return 0;
	115
	116	return pc;
	117	}
	118
baed091b ML	119	/* Return whether PC is in a GNU/Linux sigtramp routine. */
baed091b ML	120
c4f35dd8	121	static int
51433e4b	122	amd64_linux_pc_in_sigtramp (CORE_ADDR pc, char *name)
baed091b	123	{
c4f35dd8 MK	124	/* If we have NAME, we can optimize the search. The trampoline is
	125	named __restore_rt. However, it isn't dynamically exported from
	126	the shared C library, so the trampoline may appear to be part of
	127	the preceding function. This should always be sigaction,
	128	__sigaction, or __libc_sigaction (all aliases to the same
	129	function). */
	130	if (name == NULL \|\| strstr (name, "sigaction") != NULL)
51433e4b	131	return (amd64_linux_sigtramp_start (pc) != 0);
c4f35dd8 MK	132
c4f35dd8 MK	133	return (strcmp ("__restore_rt", name) == 0);
baed091b ML	134	}
baed091b ML	135
c4f35dd8	136	/* Offset to struct sigcontext in ucontext, from <asm/ucontext.h>. */
51433e4b	137	#define AMD64_LINUX_UCONTEXT_SIGCONTEXT_OFFSET 40
b64bbf8c	138
c4f35dd8 MK	139	/* Assuming NEXT_FRAME is a frame following a GNU/Linux sigtramp
c4f35dd8 MK	140	routine, return the address of the associated sigcontext structure. */
baed091b	141
c4f35dd8	142	static CORE_ADDR
51433e4b	143	amd64_linux_sigcontext_addr (struct frame_info *next_frame)
baed091b	144	{
c4f35dd8 MK	145	CORE_ADDR sp;
	146	char buf[8];
	147
	148	frame_unwind_register (next_frame, SP_REGNUM, buf);
	149	sp = extract_unsigned_integer (buf, 8);
	150
	151	/* The sigcontext structure is part of the user context. A pointer
	152	to the user context is passed as the third argument to the signal
	153	handler, i.e. in %rdx. Unfortunately %rdx isn't preserved across
	154	function calls so we can't use it. Fortunately the user context
	155	is part of the signal frame and the unwound %rsp directly points
	156	at it. */
51433e4b	157	return sp + AMD64_LINUX_UCONTEXT_SIGCONTEXT_OFFSET;
baed091b	158	}
2213a65d MK	159	\f
2213a65d MK	160
2b5e0749	161	/* From <asm/sigcontext.h>. */
51433e4b	162	static int amd64_linux_sc_reg_offset[] =
2b5e0749 MK	163	{
	164	13 * 8, /* %rax */
	165	11 * 8, /* %rbx */
	166	14 * 8, /* %rcx */
	167	12 * 8, /* %rdx */
	168	9 * 8, /* %rsi */
	169	8 * 8, /* %rdi */
	170	10 * 8, /* %rbp */
	171	15 * 8, /* %rsp */
	172	0 * 8, /* %r8 */
	173	1 * 8, /* %r9 */
	174	2 * 8, /* %r10 */
	175	3 * 8, /* %r11 */
	176	4 * 8, /* %r12 */
	177	5 * 8, /* %r13 */
	178	6 * 8, /* %r14 */
	179	7 * 8, /* %r15 */
	180	16 * 8, /* %rip */
	181	17 * 8, /* %eflags */
2b5e0749	182
af233647	183	/* FIXME: kettenis/2002030531: The registers %cs, %fs and %gs are
2b5e0749 MK	184	available in `struct sigcontext'. However, they only occupy two
	185	bytes instead of four, which makes using them here rather
	186	difficult. Leave them out for now. */
af233647 MK	187	-1, /* %cs */
	188	-1, /* %ss */
	189	-1, /* %ds */
	190	-1, /* %es */
2b5e0749 MK	191	-1, /* %fs */
	192	-1 /* %gs */
	193	};
	194
2213a65d	195	static void
51433e4b	196	amd64_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
2213a65d	197	{
c4f35dd8	198	struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
187e21d1 MK	199
	200	tdep->gregset_reg_offset = amd64_linux_gregset_reg_offset;
	201	tdep->gregset_num_regs = ARRAY_SIZE (amd64_linux_gregset_reg_offset);
	202	tdep->sizeof_gregset = 27 * 8;
	203
90f90721	204	amd64_init_abi (info, gdbarch);
c4f35dd8	205
f561f026	206	set_gdbarch_deprecated_pc_in_sigtramp (gdbarch, amd64_linux_pc_in_sigtramp);
51433e4b MK	207	tdep->sigcontext_addr = amd64_linux_sigcontext_addr;
	208	tdep->sc_reg_offset = amd64_linux_sc_reg_offset;
	209	tdep->sc_num_regs = ARRAY_SIZE (amd64_linux_sc_reg_offset);
187e21d1 MK	210
	211	/* GNU/Linux uses SVR4-style shared libraries. */
	212	set_solib_svr4_fetch_link_map_offsets
	213	(gdbarch, svr4_lp64_fetch_link_map_offsets);
2213a65d	214	}
c4f35dd8	215	\f
2213a65d MK	216
2213a65d MK	217	/* Provide a prototype to silence -Wmissing-prototypes. */
51433e4b	218	extern void _initialize_amd64_linux_tdep (void);
2213a65d MK	219
2213a65d MK	220	void
51433e4b	221	_initialize_amd64_linux_tdep (void)
2213a65d	222	{
51433e4b MK	223	gdbarch_register_osabi (bfd_arch_i386, bfd_mach_x86_64,
51433e4b MK	224	GDB_OSABI_LINUX, amd64_linux_init_abi);
2213a65d	225	}