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>
---
gdb/Makefile.in | 2 +-
gdb/configure.nat | 2 +-
gdb/i386-linux-nat.c | 26 +++------------
gdb/{i386-linux-nat.h => nat/i386-linux.c} | 15 +++++----
gdb/nat/i386-linux.h | 37 ++++++++++++++++++++++
gdb/x86-linux-nat.c | 6 ++--
gdbserver/configure.srv | 1 +
gdbserver/linux-x86-low.cc | 19 +++--------
8 files changed, 62 insertions(+), 46 deletions(-)
rename gdb/{i386-linux-nat.h => nat/i386-linux.c} (77%)
create mode 100644 gdb/nat/i386-linux.h
@@ -1397,7 +1397,6 @@ HFILES_NO_SRCDIR = \
hppa-tdep.h \
i386-bsd-nat.h \
i386-darwin-tdep.h \
- i386-linux-nat.h \
i386-linux-tdep.h \
i386-tdep.h \
i387-tdep.h \
@@ -1594,6 +1593,7 @@ HFILES_NO_SRCDIR = \
nat/gdb_ptrace.h \
nat/gdb_thread_db.h \
nat/fork-inferior.h \
+ nat/i386-linux.h \
nat/linux-btrace.h \
nat/linux-namespaces.h \
nat/linux-nat.h \
@@ -256,7 +256,7 @@ case ${gdb_host} in
NATDEPFILES="${NATDEPFILES} x86-nat.o nat/x86-dregs.o \
nat/x86-xstate.o \
i386-linux-nat.o x86-linux-nat.o nat/linux-btrace.o \
- nat/x86-linux.o nat/x86-linux-dregs.o"
+ nat/x86-linux.o nat/x86-linux-dregs.o nat/i386-linux.o"
;;
ia64)
# Host: Intel IA-64 running GNU/Linux
@@ -26,7 +26,7 @@
#include "gregset.h"
#include "gdb_proc_service.h"
-#include "i386-linux-nat.h"
+#include "nat/i386-linux.h"
#include "i387-tdep.h"
#include "i386-tdep.h"
#include "i386-linux-tdep.h"
@@ -80,22 +80,6 @@ int have_ptrace_getregs =
0
#endif
;
-
-/* Does the current host support the GETFPXREGS request? The header
- file may or may not define it, and even if it is defined, the
- kernel will return EIO if it's running on a pre-SSE processor.
-
- 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 simple variable. */
-int have_ptrace_getfpxregs =
-#ifdef HAVE_PTRACE_GETFPXREGS
- -1
-#else
- 0
-#endif
-;
/* Accessing registers through the U area, one at a time. */
@@ -388,14 +372,14 @@ fetch_fpxregs (struct regcache *regcache, int tid)
{
elf_fpxregset_t fpxregs;
- if (! have_ptrace_getfpxregs)
+ if (have_ptrace_getfpxregs == TRIBOOL_FALSE)
return 0;
if (ptrace (PTRACE_GETFPXREGS, tid, 0, (int) &fpxregs) < 0)
{
if (errno == EIO)
{
- have_ptrace_getfpxregs = 0;
+ have_ptrace_getfpxregs = TRIBOOL_FALSE;
return 0;
}
@@ -415,14 +399,14 @@ store_fpxregs (const struct regcache *regcache, int tid, int regno)
{
elf_fpxregset_t fpxregs;
- if (! have_ptrace_getfpxregs)
+ if (have_ptrace_getfpxregs == TRIBOOL_FALSE)
return 0;
if (ptrace (PTRACE_GETFPXREGS, tid, 0, &fpxregs) == -1)
{
if (errno == EIO)
{
- have_ptrace_getfpxregs = 0;
+ have_ptrace_getfpxregs = TRIBOOL_FALSE;
return 0;
}
similarity index 77%
rename from gdb/i386-linux-nat.h
rename to gdb/nat/i386-linux.c
@@ -1,6 +1,6 @@
/* Native-dependent code for GNU/Linux i386.
- Copyright (C) 1999-2024 Free Software Foundation, Inc.
+ Copyright (C) 2024 Free Software Foundation, Inc.
This file is part of GDB.
@@ -17,10 +17,13 @@
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 I386_LINUX_NAT_H
-#define I386_LINUX_NAT_H 1
-
-/* Does the current host support the GETFPXREGS request? */
-extern int have_ptrace_getfpxregs;
+#include "nat/i386-linux.h"
+/* See nat/i386-linux.h. */
+tribool have_ptrace_getfpxregs =
+#ifdef HAVE_PTRACE_GETFPXREGS
+ TRIBOOL_UNKNOWN
+#else
+ TRIBOOL_FALSE
#endif
+;
new file mode 100644
@@ -0,0 +1,37 @@
+/* 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 */
@@ -27,7 +27,7 @@
#include "x86-nat.h"
#ifndef __x86_64__
-#include "i386-linux-nat.h"
+#include "nat/i386-linux.h"
#endif
#include "x86-linux-nat.h"
#include "i386-linux-tdep.h"
@@ -147,13 +147,13 @@ x86_linux_nat_target::read_description ()
error (_("Can't debug 64-bit process with 32-bit GDB"));
}
#elif HAVE_PTRACE_GETFPXREGS
- if (have_ptrace_getfpxregs == -1)
+ if (have_ptrace_getfpxregs == TRIBOOL_UNKNOWN)
{
elf_fpxregset_t fpxregs;
if (ptrace (PTRACE_GETFPXREGS, tid, 0, (int) &fpxregs) < 0)
{
- have_ptrace_getfpxregs = 0;
+ have_ptrace_getfpxregs = TRIBOOL_FALSE;
have_ptrace_getregset = TRIBOOL_FALSE;
return i386_linux_read_description (X86_XSTATE_X87_MASK);
}
@@ -109,6 +109,7 @@ case "${gdbserver_host}" in
srv_tgtobj="${srv_tgtobj} nat/linux-btrace.o"
srv_tgtobj="${srv_tgtobj} nat/x86-linux.o"
srv_tgtobj="${srv_tgtobj} nat/x86-linux-dregs.o"
+ srv_tgtobj="${srv_tgtobj} nat/i386-linux.o"
srv_linux_usrregs=yes
srv_linux_regsets=yes
srv_linux_thread_db=yes
@@ -29,6 +29,8 @@
#ifdef __x86_64__
#include "nat/amd64-linux-siginfo.h"
+#else
+#include "nat/i386-linux.h"
#endif
#include "gdb_proc_service.h"
@@ -831,17 +833,6 @@ x86_target::low_siginfo_fixup (siginfo_t *ptrace, gdb_byte *inf, int direction)
static int use_xml;
-/* Does the current host support the GETFPXREGS request? The header
- file may or may not define it, and even if it is defined, the
- kernel will return EIO if it's running on a pre-SSE processor. */
-int have_ptrace_getfpxregs =
-#ifdef HAVE_PTRACE_GETFPXREGS
- -1
-#else
- 0
-#endif
-;
-
/* Get Linux/x86 target description from running target. */
static const struct target_desc *
@@ -886,18 +877,18 @@ x86_linux_read_description (void)
}
#if !defined __x86_64__ && defined HAVE_PTRACE_GETFPXREGS
- if (machine == EM_386 && have_ptrace_getfpxregs == -1)
+ if (machine == EM_386 && have_ptrace_getfpxregs == TRIBOOL_UNKNOWN)
{
elf_fpxregset_t fpxregs;
if (ptrace (PTRACE_GETFPXREGS, tid, 0, (long) &fpxregs) < 0)
{
- have_ptrace_getfpxregs = 0;
+ have_ptrace_getfpxregs = TRIBOOL_FALSE;
have_ptrace_getregset = TRIBOOL_FALSE;
return i386_linux_read_description (X86_XSTATE_X87);
}
else
- have_ptrace_getfpxregs = 1;
+ have_ptrace_getfpxregs = TRIBOOL_TRUE;
}
#endif