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/* Target-dependent code for GNU/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 "gdb_string.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[] = {
/* 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
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 0
/* Offset to struct sigcontext in ucontext, from <asm/ucontext.h>. */
#define LINUX_UCONTEXT_SIGCONTEXT_OFFSET 40
/* Offset to saved PC in sigcontext, from <asm/sigcontext.h>. */
#define LINUX_SIGCONTEXT_PC_OFFSET 128
#define LINUX_SIGCONTEXT_FP_OFFSET 120
/* Assuming FRAME is for a GNU/Linux sigtramp routine, return the
address of the associated sigcontext structure. */
static CORE_ADDR
x86_64_linux_sigcontext_addr (struct frame_info *frame)
{
CORE_ADDR pc;
ULONGEST rsp;
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. */
rsp = read_register (SP_REGNUM);
return rsp + LINUX_SIGINFO_SIZE + LINUX_UCONTEXT_SIGCONTEXT_OFFSET;
}
error ("Couldn't recognize signal trampoline.");
return 0;
}
/* Assuming FRAME is for a GNU/Linux sigtramp routine, return the
saved program counter. */
static 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);
}
/* Return whether PC is in a GNU/Linux sigtramp routine. */
int
x86_64_linux_in_sigtramp (CORE_ADDR pc, char *name)
{
if (name)
return STREQ ("__restore_rt", name);
return (x86_64_linux_sigtramp_start (pc) != 0);
}
CORE_ADDR
x86_64_linux_frame_chain (struct frame_info *fi)
{
ULONGEST addr;
CORE_ADDR fp, pc;
if (!fi->signal_handler_caller)
{
fp = cfi_frame_chain (fi);
if (fp)
return fp;
else
addr = fi->frame;
}
else
addr = fi->next->frame;
addr += LINUX_SIGINFO_SIZE + LINUX_UCONTEXT_SIGCONTEXT_OFFSET;
fp = read_memory_integer (addr + LINUX_SIGCONTEXT_FP_OFFSET, 8) + 8;
return fp;
}
void
x86_64_init_frame_pc (int fromleaf, struct frame_info *fi)
{
CORE_ADDR addr;
if (fi->next && fi->next->signal_handler_caller)
{
addr = fi->next->next->frame
+ LINUX_SIGINFO_SIZE + LINUX_UCONTEXT_SIGCONTEXT_OFFSET;
fi->pc = read_memory_integer (addr + LINUX_SIGCONTEXT_PC_OFFSET, 8);
}
else
cfi_init_frame_pc (fromleaf, fi);
}
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