binutils-gdb/gdb/elf-none-tdep.c
Andrew Burgess c14993e9dc gdb/corefile: write NT_GDB_TDESC based on signalled thread
When creating a core file from within GDB we include a NT_GDB_TDESC
that includes the target description of the architecture in use.

For architectures with dynamic architectures (e.g. AArch64 with
sve/sme) the original architecture, calculated from the original
target description, might not match the per-thread architecture.

In the general case, where each thread has a different architecture,
then we really need a separate NT_GDB_TDESC for each thread, however,
there's currently no way to read in multiple NT_GDB_TDESC.

This commit is a step towards per-thread NT_GDB_TDESC.  In this commit
I have updated the function that writes the NT_GDB_TDESC to accept a
gdbarch (rather than calling target_gdbarch() to find a gdbarch), and
I now pass in the gdbarch of the signalled thread.

In many cases (though NOT all) targets with dynamic architectures
really only use a single architecture, even when there are multiple
threads, so in the common case, this should ensure that GDB emits an
architecture that is more likely to be correct.

Additional work will be needed in order to support corefiles with
truly per-thread architectures, but that will need to be done in the
future.
2023-10-03 17:43:50 +01:00

131 lines
4.2 KiB
C

/* Common code for targets with the none ABI (bare-metal), but where the
BFD library is build with ELF support.
Copyright (C) 2020-2023 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 "defs.h"
#include "elf-none-tdep.h"
#include "regset.h"
#include "elf-bfd.h"
#include "inferior.h"
#include "regcache.h"
#include "gdbarch.h"
#include "gcore.h"
#include "gcore-elf.h"
/* Build the note section for a corefile, and return it in a malloc
buffer. Currently this just dumps all available registers for each
thread. */
static gdb::unique_xmalloc_ptr<char>
elf_none_make_corefile_notes (struct gdbarch *gdbarch, bfd *obfd,
int *note_size)
{
gdb::unique_xmalloc_ptr<char> note_data;
/* Add note information about the executable and its arguments. */
std::string fname;
std::string psargs;
static const size_t fname_len = 16;
static const size_t psargs_len = 80;
if (get_exec_file (0))
{
const char *exe = get_exec_file (0);
fname = lbasename (exe);
psargs = std::string (exe);
const std::string &infargs = current_inferior ()->args ();
if (!infargs.empty ())
psargs += ' ' + infargs;
/* All existing targets that handle writing out prpsinfo expect the
fname and psargs strings to be at least 16 and 80 characters long
respectively, including a null terminator at the end. Resize to
the expected length minus one to ensure there is a null within the
required length. */
fname.resize (fname_len - 1);
psargs.resize (psargs_len - 1);
}
/* Resize the buffers up to their required lengths. This will fill any
remaining space with the null character. */
fname.resize (fname_len);
psargs.resize (psargs_len);
/* Now write out the prpsinfo structure. */
note_data.reset (elfcore_write_prpsinfo (obfd, note_data.release (),
note_size, fname.c_str (),
psargs.c_str ()));
if (note_data == nullptr)
return nullptr;
/* Thread register information. */
try
{
update_thread_list ();
}
catch (const gdb_exception_error &e)
{
exception_print (gdb_stderr, e);
}
/* Like the Linux kernel, prefer dumping the signalled thread first.
"First thread" is what tools use to infer the signalled thread. */
thread_info *signalled_thr = gcore_find_signalled_thread ();
/* All threads are reported as having been stopped by the same signal
that stopped SIGNALLED_THR. */
gdb_signal stop_signal;
if (signalled_thr != nullptr)
stop_signal = signalled_thr->stop_signal ();
else
stop_signal = GDB_SIGNAL_0;
if (signalled_thr != nullptr)
gcore_elf_build_thread_register_notes (gdbarch, signalled_thr,
stop_signal, obfd, &note_data,
note_size);
for (thread_info *thr : current_inferior ()->non_exited_threads ())
{
if (thr == signalled_thr)
continue;
gcore_elf_build_thread_register_notes (gdbarch, thr, stop_signal, obfd,
&note_data, note_size);
}
/* Include the target description when possible. Some architectures
allow for per-thread gdbarch so we should really be emitting a tdesc
per-thread, however, we don't currently support reading in a
per-thread tdesc, so just emit the tdesc for the signalled thread. */
gdbarch = target_thread_architecture (signalled_thr->ptid);
gcore_elf_make_tdesc_note (gdbarch, obfd, &note_data, note_size);
return note_data;
}
/* See none-tdep.h. */
void
elf_none_init_abi (struct gdbarch *gdbarch)
{
/* Default core file support. */
set_gdbarch_make_corefile_notes (gdbarch, elf_none_make_corefile_notes);
}