From 18d4886c009aaa4fa26bf440ae57fbdd14acce11 Mon Sep 17 00:00:00 2001 From: Andrew Burgess Date: Fri, 26 Apr 2024 14:24:40 +0100 Subject: [PATCH] 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 --- 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 diff --git a/gdb/Makefile.in b/gdb/Makefile.in index 3752bdff79b..277f878371c 100644 --- a/gdb/Makefile.in +++ b/gdb/Makefile.in @@ -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 \ diff --git a/gdb/configure.nat b/gdb/configure.nat index 8b98511cef7..25268bb268b 100644 --- a/gdb/configure.nat +++ b/gdb/configure.nat @@ -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 diff --git a/gdb/i386-linux-nat.c b/gdb/i386-linux-nat.c index 7278dd91ff0..bfe3fb84d0a 100644 --- a/gdb/i386-linux-nat.c +++ b/gdb/i386-linux-nat.c @@ -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; } diff --git a/gdb/i386-linux-nat.h b/gdb/nat/i386-linux.c similarity index 77% rename from gdb/i386-linux-nat.h rename to gdb/nat/i386-linux.c index c3d32aff1be..64605be4fc5 100644 --- a/gdb/i386-linux-nat.h +++ b/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 . */ -#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 +; diff --git a/gdb/nat/i386-linux.h b/gdb/nat/i386-linux.h new file mode 100644 index 00000000000..c93626b6439 --- /dev/null +++ b/gdb/nat/i386-linux.h @@ -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 . */ + +#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 */ diff --git a/gdb/x86-linux-nat.c b/gdb/x86-linux-nat.c index a3d8ffb60f1..762151ff378 100644 --- a/gdb/x86-linux-nat.c +++ b/gdb/x86-linux-nat.c @@ -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); } diff --git a/gdbserver/configure.srv b/gdbserver/configure.srv index 9e861a75088..8e882d2159b 100644 --- a/gdbserver/configure.srv +++ b/gdbserver/configure.srv @@ -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 diff --git a/gdbserver/linux-x86-low.cc b/gdbserver/linux-x86-low.cc index e8ef3667eb4..2d99a82f566 100644 --- a/gdbserver/linux-x86-low.cc +++ b/gdbserver/linux-x86-low.cc @@ -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