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/* Target-dependent code for Linux running on x86-64, for GDB.
Copyright 2001
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 "inferior.h"
#include "gdbcore.h"
#include "regcache.h"
#include "x86-64-tdep.h"
#include "dwarf2cfi.h"
#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[] = {
LINUX_SIGTRAMP_INSN0, 0xc7, 0xc0, 0x89, 0x00, 0x00, 0x00, /* mov $0x89,%rax */
LINUX_SIGTRAMP_INSN1, 0x05 /* syscall */
};
#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
x86_64_linux_sigtramp_start (CORE_ADDR pc)
{
unsigned char buf[LINUX_SIGTRAMP_LEN];
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;
}
#define LINUX_SIGINFO_SIZE 128
/* Offset to struct sigcontext in ucontext, from <asm/ucontext.h>. */
#define LINUX_UCONTEXT_SIGCONTEXT_OFFSET (36)
/* Assuming FRAME is for a Linux sigtramp routine, return the address
of the associated sigcontext structure. */
CORE_ADDR
x86_64_linux_sigcontext_addr (struct frame_info *frame)
{
CORE_ADDR pc;
pc = x86_64_linux_sigtramp_start (frame->pc);
if (pc)
{
if (frame->next)
/* If this isn't the top frame, the next frame must be for the
signal handler itself. The sigcontext structure is part of
the user context. */
return frame->next->frame + LINUX_SIGINFO_SIZE +
LINUX_UCONTEXT_SIGCONTEXT_OFFSET;
/* This is the top frame. */
return read_register (SP_REGNUM) + LINUX_SIGINFO_SIZE +
LINUX_UCONTEXT_SIGCONTEXT_OFFSET;
}
error ("Couldn't recognize signal trampoline.");
return 0;
}
/* Offset to saved PC in sigcontext, from <asm/sigcontext.h>. */
#define LINUX_SIGCONTEXT_PC_OFFSET (136)
/* Assuming FRAME is for a Linux sigtramp routine, return the saved
program counter. */
CORE_ADDR
x86_64_linux_sigtramp_saved_pc (struct frame_info *frame)
{
CORE_ADDR addr;
addr = x86_64_linux_sigcontext_addr (frame);
return read_memory_integer (addr + LINUX_SIGCONTEXT_PC_OFFSET, 8);
}
/* Immediately after a function call, return the saved pc. */
CORE_ADDR
x86_64_linux_saved_pc_after_call (struct frame_info *frame)
{
if (frame->signal_handler_caller)
return x86_64_linux_sigtramp_saved_pc (frame);
return read_memory_integer (read_register (SP_REGNUM), 8);
}
/* Saved Pc. Get it from sigcontext if within sigtramp. */
CORE_ADDR
x86_64_linux_frame_saved_pc (struct frame_info *frame)
{
if (frame->signal_handler_caller)
return x86_64_linux_sigtramp_saved_pc (frame);
return cfi_get_ra (frame);
}
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