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/* Native-dependent code for GNU/Linux x86 (i386 and x86-64).
Copyright (C) 1999-2024 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 3 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, see <http://www.gnu.org/licenses/>. */
#include "x86-linux.h"
#include "x86-linux-dregs.h"
#include "nat/gdb_ptrace.h"
#include <sys/user.h>
/* Per-thread arch-specific data we want to keep. */
struct arch_lwp_info
{
/* Non-zero if our copy differs from what's recorded in the
thread. */
int debug_registers_changed;
};
/* See nat/x86-linux.h. */
void
lwp_set_debug_registers_changed (struct lwp_info *lwp, int value)
{
if (lwp_arch_private_info (lwp) == NULL)
lwp_set_arch_private_info (lwp, XCNEW (struct arch_lwp_info));
lwp_arch_private_info (lwp)->debug_registers_changed = value;
}
/* See nat/x86-linux.h. */
int
lwp_debug_registers_changed (struct lwp_info *lwp)
{
struct arch_lwp_info *info = lwp_arch_private_info (lwp);
/* NULL means either that this is the main thread still going
through the shell, or that no watchpoint has been set yet.
The debug registers are unchanged in either case. */
if (info == NULL)
return 0;
return info->debug_registers_changed;
}
/* See nat/x86-linux.h. */
void
x86_linux_new_thread (struct lwp_info *lwp)
{
lwp_set_debug_registers_changed (lwp, 1);
}
/* See nat/x86-linux.h. */
void
x86_linux_delete_thread (struct arch_lwp_info *arch_lwp)
{
xfree (arch_lwp);
}
/* See nat/x86-linux.h. */
void
x86_linux_prepare_to_resume (struct lwp_info *lwp)
{
x86_linux_update_debug_registers (lwp);
}
#ifdef __x86_64__
/* Value of CS segment register:
64bit process: 0x33
32bit process: 0x23 */
#define AMD64_LINUX_USER64_CS 0x33
/* Value of DS segment register:
LP64 process: 0x0
X32 process: 0x2b */
#define AMD64_LINUX_X32_DS 0x2b
#endif
/* See nat/x86-linux.h. */
x86_linux_arch_size
x86_linux_ptrace_get_arch_size (int tid)
{
#ifdef __x86_64__
unsigned long cs;
unsigned long ds;
/* Get CS register. */
errno = 0;
cs = ptrace (PTRACE_PEEKUSER, tid,
offsetof (struct user_regs_struct, cs), 0);
if (errno != 0)
perror_with_name (_("Couldn't get CS register"));
bool is_64bit = cs == AMD64_LINUX_USER64_CS;
/* Get DS register. */
errno = 0;
ds = ptrace (PTRACE_PEEKUSER, tid,
offsetof (struct user_regs_struct, ds), 0);
if (errno != 0)
perror_with_name (_("Couldn't get DS register"));
bool is_x32 = ds == AMD64_LINUX_X32_DS;
return x86_linux_arch_size (is_64bit, is_x32);
#else
return x86_linux_arch_size (false, false);
#endif
}
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