1 /* Target-dependent code for GNU/Linux running on x86-64, for GDB.
3 Copyright 2001 Free Software Foundation, Inc.
5 Contributed by Jiri Smid, SuSE Labs.
7 This file is part of GDB.
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 2 of the License, or
12 (at your option) any later version.
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.
19 You should have received a copy of the GNU General Public License
20 along with this program; if not, write to the Free Software
21 Foundation, Inc., 59 Temple Place - Suite 330,
22 Boston, MA 02111-1307, USA. */
28 #include "x86-64-tdep.h"
29 #include "dwarf2cfi.h"
31 #define LINUX_SIGTRAMP_INSN0 (0x48) /* mov $NNNNNNNN,%rax */
32 #define LINUX_SIGTRAMP_OFFSET0 (0)
33 #define LINUX_SIGTRAMP_INSN1 (0x0f) /* syscall */
34 #define LINUX_SIGTRAMP_OFFSET1 (7)
36 static const unsigned char linux_sigtramp_code
[] = {
37 LINUX_SIGTRAMP_INSN0
, 0xc7, 0xc0, 0x89, 0x00, 0x00, 0x00, /* mov $0x89,%rax */
38 LINUX_SIGTRAMP_INSN1
, 0x05 /* syscall */
41 #define LINUX_SIGTRAMP_LEN (sizeof linux_sigtramp_code)
43 /* If PC is in a sigtramp routine, return the address of the start of
44 the routine. Otherwise, return 0. */
47 x86_64_linux_sigtramp_start (CORE_ADDR pc
)
49 unsigned char buf
[LINUX_SIGTRAMP_LEN
];
50 if (read_memory_nobpt (pc
, (char *) buf
, LINUX_SIGTRAMP_LEN
) != 0)
53 if (buf
[0] != LINUX_SIGTRAMP_INSN0
)
55 if (buf
[0] != LINUX_SIGTRAMP_INSN1
)
58 pc
-= LINUX_SIGTRAMP_OFFSET1
;
60 if (read_memory_nobpt (pc
, (char *) buf
, LINUX_SIGTRAMP_LEN
) != 0)
64 if (memcmp (buf
, linux_sigtramp_code
, LINUX_SIGTRAMP_LEN
) != 0)
70 #define LINUX_SIGINFO_SIZE 128
72 /* Offset to struct sigcontext in ucontext, from <asm/ucontext.h>. */
73 #define LINUX_UCONTEXT_SIGCONTEXT_OFFSET (36)
75 /* Assuming FRAME is for a GNU/Linux sigtramp routine, return the
76 address of the associated sigcontext structure. */
78 x86_64_linux_sigcontext_addr (struct frame_info
*frame
)
82 pc
= x86_64_linux_sigtramp_start (frame
->pc
);
86 /* If this isn't the top frame, the next frame must be for the
87 signal handler itself. The sigcontext structure is part of
89 return frame
->next
->frame
+ LINUX_SIGINFO_SIZE
+
90 LINUX_UCONTEXT_SIGCONTEXT_OFFSET
;
93 /* This is the top frame. */
94 return read_register (SP_REGNUM
) + LINUX_SIGINFO_SIZE
+
95 LINUX_UCONTEXT_SIGCONTEXT_OFFSET
;
99 error ("Couldn't recognize signal trampoline.");
103 /* Offset to saved PC in sigcontext, from <asm/sigcontext.h>. */
104 #define LINUX_SIGCONTEXT_PC_OFFSET (136)
106 /* Assuming FRAME is for a GNU/Linux sigtramp routine, return the
107 saved program counter. */
110 x86_64_linux_sigtramp_saved_pc (struct frame_info
*frame
)
114 addr
= x86_64_linux_sigcontext_addr (frame
);
115 return read_memory_integer (addr
+ LINUX_SIGCONTEXT_PC_OFFSET
, 8);
118 /* Immediately after a function call, return the saved pc. */
121 x86_64_linux_saved_pc_after_call (struct frame_info
*frame
)
123 if (frame
->signal_handler_caller
)
124 return x86_64_linux_sigtramp_saved_pc (frame
);
126 return read_memory_integer (read_register (SP_REGNUM
), 8);
129 /* Saved Pc. Get it from sigcontext if within sigtramp. */
131 x86_64_linux_frame_saved_pc (struct frame_info
*frame
)
133 if (frame
->signal_handler_caller
)
134 return x86_64_linux_sigtramp_saved_pc (frame
);
135 return cfi_get_ra (frame
);