binutils-gdb/gdb/nat/i386-linux.h
Andrew Burgess 18d4886c00 gdb/x86: move have_ptrace_getfpxregs global into gdb/nat directory
The have_ptrace_getfpxregs global tracks whether GDB or gdbserver is
running on a kernel that supports the GETFPXREGS ptrace request.

Currently this global is declared twice (once in GDB and once in
gdbserver), I think it makes sense to move this global into the nat/
directory, and have a single declaration and definition.

While moving this variable I have converted it to a tribool, as that
was what it really was, if even used the same numbering as the tribool
enum (-1, 0, 1).  Where have_ptrace_getfpxregs was used I have updated
in the obvious way.

However, while making this change I noticed what I think is a bug in
x86_linux_nat_target::read_description and x86_linux_read_description,
both of these functions can be called multiple times, but in both
cases we only end up calling i386_linux_read_description the first
time through in the event that PTRACE_GETFPXREGS is not supported.
This is because initially have_ptrace_getfpxregs will be
TRIBOOL_UNKNOWN, but after the ptrace call fails we set
have_ptrace_getfpxregs to TRIBOOL_FALSE.  The next time we attempt to
read the target description we'll skip the ptrace call, and so skip
the call to i386_linux_read_description.

I've not tried to address this preexisting bug in this commit, this is
purely a refactor, there should be no user visible changes after this
commit.  In later commits I'll merge the gdbserver and GDB code
together into the nat/ directory, and after that I'll try to address
this bug.

Reviewed-By: Felix Willgerodt <felix.willgerodt@intel.com>
2024-06-14 09:08:45 +01:00

38 lines
1.5 KiB
C

/* Native-dependent code for GNU/Linux i386.
Copyright (C) 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/>. */
#ifndef NAT_I386_LINUX_H
#define NAT_I386_LINUX_H
/* Does the current host support the GETFPXREGS request? The system header
file may or may not define it, but even if it is defined, the kernel
will return EIO if it's running on a pre-SSE processor.
Initially this will be TRIBOOL_UNKNOWN and should be changed to
TRIBOOL_FALSE if the ptrace call is attempted and fails or changed to
TRIBOOL_TRUE if the ptrace call is attempted and succeeds.
My instinct is to attach this to some architecture- or target-specific
data structure, but really, a particular GDB process can only run on top
of one kernel at a time. So it's okay - for this to be a global
variable. */
extern tribool have_ptrace_getfpxregs;
#endif /* NAT_I386_LINUX_H */