While reviewing the native AArch64 patch, I noticed a problem:
On 02/06/2013 08:46 PM, Pedro Alves wrote:
>
>> > +static void
>> > +aarch64_linux_prepare_to_resume (struct lwp_info *lwp)
>> > +{
>> > + struct arch_lwp_info *info = lwp->arch_private;
>> > +
>> > + /* NULL means this is the main thread still going through the shell,
>> > + or, no watchpoint has been set yet. In that case, there's
>> > + nothing to do. */
>> > + if (info == NULL)
>> > + return;
>> > +
>> > + if (DR_HAS_CHANGED (info->dr_changed_bp)
>> > + || DR_HAS_CHANGED (info->dr_changed_wp))
>> > + {
>> > + int tid = GET_LWP (lwp->ptid);
>> > + struct aarch64_debug_reg_state *state = aarch64_get_debug_reg_state ();
> Hmm. This is always fetching the debug_reg_state of
> the current inferior, but may not be the inferior of lwp.
> I see the same bug on x86. Sorry about that. I'll fix it.
A natural fix would be to make xxx_get_debug_reg_state take an
inferior argument, but that doesn't work because of the case where we
detach breakpoints/watchpoints from the child fork, at a time there's
no inferior for the child fork at all. We do a nasty hack in
i386_inferior_data_get, but that relies on all callers pointing the
current inferior to the correct inferior, which isn't actually being
done by all callers, and I don't think we want to enforce that -- deep
in the bowls of linux-nat.c, there are many cases we resume lwps
behind the scenes, and it's be better to not have that code rely on
global state (as it doesn't today).
The fix is to decouple the watchpoints code from inferiors, making it
track target processes instead. This way, we can freely keep track of
the watchpoint mirrors for these processes behind the core's back.
Checkpoints also play dirty tricks with swapping the process behind
the inferior, so they get special treatment too in the patch (which
just amounts to calling a new hook). Instead of the old hack in
i386_inferior_data_get, where we returned a copy of the current
inferior's debug registers mirror, as soon as we detect a fork in the
target, we copy the debug register mirror from the parent to the child
process.
I don't have an old kernel handy to test, but I stepped through gdb doing
the watchpoint removal in the fork child in the watchpoint-fork test
seeing that the debug registers end up cleared in the child.
I didn't find the need for linux_nat_iterate_watchpoint_lwps. If
we use plain iterate_over_lwps instead, what happens is that
when removing watchpoints, that iterate_over_lwps doesn't actually
iterate over anything, since the fork child is not added to the
lwp list until later, at detach time, in linux_child_follow_fork.
And if we don't iterate over that lwp, we don't mark its debug
registers as needing update. But linux_child_follow_fork takes
care of doing that explicitly:
child_lp = add_lwp (inferior_ptid);
child_lp->stopped = 1;
child_lp->last_resume_kind = resume_stop;
make_cleanup (delete_lwp_cleanup, child_lp);
/* CHILD_LP has new PID, therefore linux_nat_new_thread is not called for it.
See i386_inferior_data_get for the Linux kernel specifics.
Ensure linux_nat_prepare_to_resume will reset the hardware debug
registers. It is done by the linux_nat_new_thread call, which is
being skipped in add_lwp above for the first lwp of a pid. */
gdb_assert (num_lwps (GET_PID (child_lp->ptid)) == 1);
if (linux_nat_new_thread != NULL)
linux_nat_new_thread (child_lp);
if (linux_nat_prepare_to_resume != NULL)
linux_nat_prepare_to_resume (child_lp);
ptrace (PTRACE_DETACH, child_pid, 0, 0);
so unless I'm missing something (quite possible) it ends up all
the same. But, the !detach-on-fork, and the "follow-fork child" paths
should also call linux_nat_new_thread, and they don't presently. It
seems to me in those cases we're not clearing debug regs correctly
when that's needed. Instead of copying that bit that works around
add_lwp bypassing the linux_nat_new_thread call, I thought it'd
be better to add an add_initial_lwp call to be used in the case we
really need to bypass linux_nat_new_thread, and make
add_lwp always call linux_nat_new_thread.
i386_cleanup_dregs is rewritten to forget about the current process
debug mirrors, which takes cares of other i386 ports. Only a couple
of extra tweaks here and there were needed, as some targets wheren't
actually calling i386_cleanup_dregs.
Tested on Fedora 17 x86_64 -m64/-m32.
GDBserver already fetches the i386_debug_reg_state from the right
process, and, it doesn't handle forks at all, so no fix is needed over
there.
gdb/
2013-02-13 Pedro Alves <palves@redhat.com>
* amd64-linux-nat.c (update_debug_registers_callback):
Update comment.
(amd64_linux_dr_set_control, amd64_linux_dr_set_addr): Use
iterate_over_lwps.
(amd64_linux_prepare_to_resume): Pass the lwp's pid to
i386_debug_reg_state.
(amd64_linux_new_fork): New function.
(_initialize_amd64_linux_nat): Install amd64_linux_new_fork as
linux_nat_new_fork hook, and i386_forget_process as
linux_nat_forget_process hook.
* i386-linux-nat.c (update_debug_registers_callback):
Update comment.
(amd64_linux_dr_set_control, amd64_linux_dr_set_addr): Use
iterate_over_lwps.
(i386_linux_prepare_to_resume): Pass the lwp's pid to
i386_debug_reg_state.
(i386_linux_new_fork): New function.
(_initialize_i386_linux_nat): Install i386_linux_new_fork as
linux_nat_new_fork hook, and i386_forget_process as
linux_nat_forget_process hook.
* i386-nat.c (i386_init_dregs): Delete.
(i386_inferior_data, struct i386_inferior_data):
Delete.
(struct i386_process_info): New.
(i386_process_list): New global.
(i386_find_process_pid, i386_add_process, i386_process_info_get):
New functions.
(i386_inferior_data_get): Delete.
(i386_process_info_get): New function.
(i386_debug_reg_state): New parameter 'pid'. Reimplement.
(i386_forget_process): New function.
(i386_cleanup_dregs): Rewrite.
(i386_update_inferior_debug_regs, i386_insert_watchpoint)
(i386_remove_watchpoint, i386_region_ok_for_watchpoint)
(i386_stopped_data_address, i386_insert_hw_breakpoint)
(i386_remove_hw_breakpoint): Adjust to pass the current process id
to i386_debug_reg_state.
(i386_use_watchpoints): Don't register inferior data.
* i386-nat.h (i386_debug_reg_state): Add new 'pid' parameter, and
adjust comment.
(i386_forget_process): Declare.
* linux-fork.c (delete_fork): Call linux_nat_forget_process.
* linux-nat.c (linux_nat_new_fork, linux_nat_forget_process_hook):
New static globals.
(linux_child_follow_fork): Don't call linux_nat_new_thread here.
(add_initial_lwp): New, factored out from ...
(add_lwp): ... this. Don't check the number of lwps before
calling linux_nat_new_thread.
(linux_nat_iterate_watchpoint_lwps): Delete.
(linux_nat_attach): Use add_initial_lwp instead of add_lwp.
(linux_handle_extended_wait): Call the linux_nat_new_fork hook on
forks and vforks.
(linux_nat_wait_1): Use add_initial_lwp instead of add_lwp for the
initial lwp.
(linux_nat_kill, linux_nat_mourn_inferior): Call
linux_nat_forget_process.
(linux_nat_set_new_fork, linux_nat_set_forget_process)
(linux_nat_forget_process): New functions.
* linux-nat.h (linux_nat_iterate_watchpoint_lwps_ftype): Delete
type.
(linux_nat_iterate_watchpoint_lwps): Delete declaration.
(linux_nat_new_fork_ftype, linux_nat_forget_process_ftype): New
types.
(linux_nat_set_new_fork, linux_nat_set_forget_process)
(linux_nat_forget_process): New declarations.
* amd64fbsd-nat.c (super_mourn_inferior): New global.
(amd64fbsd_mourn_inferior): New function.
(_initialize_amd64fbsd_nat): Override to_mourn_inferior.
* windows-nat.c (windows_detach): Call i386_cleanup_dregs.
Two modifications:
1. The addition of 2013 to the copyright year range for every file;
2. The use of a single year range, instead of potentially multiple
year ranges, as approved by the FSF.
2012-11-26 Maxime Villard <rustyBSD@gmx.fr>
Pedro Alves <palves@redhat.com>
* common/linux-osdata.c (linux_xfer_osdata_fds): Decrease buffer
size parameter passed to readlink by one byte.
* fbsd-nat.c (fbsd_pid_to_exec_file): Ditto.
* linux-nat.c (linux_child_pid_to_exec_file): Ditto.
* nbsd-nat.c (nbsd_pid_to_exec_file): Ditto.
* inf-child.c (inf_child_fileio_readlink): Decrease local buffer's
size by one byte.
gdb/gdbserver/
2012-11-26 Maxime Villard <rustyBSD@gmx.fr>
* hostio.c (handle_readlink): Decrease buffer size
parameter passed to readlink by one byte.
2012-11-09 Pedro Alves <palves@redhat.com>
* gdbarch.sh (target_gdbarch) <gdbarch.h>: Reimplement as macro.
(get_target_gdbarch) <gdbarch.h>: New function.
(startup_gdbarch) <gdbarch.h>: Declare.
<gdbarch.c> (target_gdbarch): Delete.
<gdbarch.c> (deprecated_target_gdbarch_select_hack): Set the
current inferior's gdbarch.
<gdbarch.c> (get_target_gdbarch): New function.
* inferior.c: Include target-descriptions.h.
(free_inferior): Free target description info.
(add_inferior_with_spaces): Set the inferior's initial
architecture.
(clone_inferior_command): Copy the original inferior's target
description if it was user specified.
(initialize_inferiors): Add comment.
* inferior.h (struct target_desc_info): Forward declare.
(struct inferior) <gdbarch>: New field.
* linux-nat.c: Include target-descriptions.h.
(linux_child_follow_fork): Copy the parent's architecture and
target description to the child.
* target-descriptions.c: Include inferior.h.
(struct target_desc_info): New structure, holding the equivalents
of ...
(target_desc_fetched, current_target_desc)
(target_description_filename): ... these removed globals.
(get_tdesc_info, target_desc_info_from_user_p)
(copy_inferior_target_desc_info, target_desc_info_free): New.
(target_desc_fetched, current_target_desc)
(target_description_filename): Reimplemented as convenience
macros.
(tdesc_filename_cmd_string): New global.
(set_tdesc_filename_cmd): Copy the string manipulated by the "set
tdescs filename ..." commands to the per-inferior equivalent.
(show_tdesc_filename_cmd): Get the value to show from the
per-inferior description filename.
(_initilize_target_descriptions): Change the "set/show tdesc
filename" commands' variable.
* target-descriptions.h (struct target_desc, struct target_desc_info)
(struct inferior): Forward declare.
(target_find_description, target_clear_description)
(target_current_description): Adjust comments.
(copy_inferior_target_desc_info, target_desc_info_free)
(target_desc_info_from_user_p). Declare.
gdb/testsuite/
2012-11-09 Pedro Alves <palves@redhat.com>
* gdb.multi/multi-arch.exp: New.
Before this change, detach_breakpoints would take a pid, and then
set inferior_ptid to a ptid that it constructs using pid_to_ptid (pid).
Unfortunately, this ptid is not necessarily valid. Consider for
instance the case of ia64-hpux, where ttrace refuses a register-read
operation if the LWP is not provided.
This problems shows up when GDB is trying to handle fork events.
Assuming GDB is configured to follow the parent, GDB will try to
detach from the child. But before doing so, it needs to remove
all breakpoints inside that child. On ia64, this involves reading
inferior (the child's) memory. And on ia64-hpux, reading memory
requires us to read the bsp and bspstore registers, in order to
determine where that memory is relative to the value of those
registers, and thus to determine which ttrace operation to use in
order to fetch that memory (see ia64_hpux_xfer_memory).
This patch therefore changes detach_breakpoints to take a ptid instead
of a pid, and then updates all callers.
One of the consequences of this patch is that it trips an assert
on GNU/Linux targets. But this assert appears to have not actual
purpose, and is thus removed.
gdb/ChangeLog:
* breakpoint.h (detach_breakpoints): pid parameter is now a ptid.
* breakpoint.c (detach_breakpoints): Change pid parameter into
a ptid. Adjust code accordingly.
* infrun.c (handle_inferior_event): Delete variable child_pid.
Update call to detach_breakpoints to pass the child ptid for
fork events.
* linux-nat.c (linux_nat_iterate_watchpoint_lwps): Remove
assert that inferior_ptid's lwp is zero.
(linux_handle_extended_wait): Update call to detach_breakpoints.
* inf-ttrace.c (inf_ttrace_follow_fork): Update call to
detach_breakpoints.
Code cleanup for the next patch.
* arm-linux-nat.c (arm_linux_stopped_data_address): Change variable
siginfo_p to siginfo, update its users incl. the linux_nat_get_siginfo
call for it.
* ia64-linux-nat.c (ia64_linux_stopped_data_address): Likewise.
(ia64_linux_stopped_data_address):
* linux-nat.c (linux_nat_get_siginfo): Add parameter siginfo, change
the return value.
* linux-nat.h (linux_nat_get_siginfo): Likewise.
* ppc-linux-nat.c (ppc_linux_stopped_data_address): Change variable
siginfo_p to siginfo, update its users incl. the linux_nat_get_siginfo
call for it.
2012-06-28 Jan Kratochvil <jan.kratochvil@redhat.com>
Pedro Alves <palves@redhat.com>
* gdbthread.h (ALL_THREADS): New macro.
(thread_list): Declare.
* infrun.c (handle_inferior_event) <spurious signal>: Don't keep
going, but instead fall through to the stepping handling.
* linux-nat.c (resume_lwp): New parameter 'signo'. Resume with
the passed in signal. Adjust debug output.
(resume_callback): Rename to ...
(linux_nat_resume_callback): ... this. Pass the thread's last
stop signal, if in "pass" state.
(linux_nat_resume): Adjust to rename.
(stop_wait_callback): New assertion. Don't respawn signals;
instead let the LWP remain with SIGNALLED set.
(linux_nat_wait_1): Remove flushing of pending SIGSTOPs.
* remote.c (append_pending_thread_resumptions): New.
(remote_vcont_resume): Call it.
* target.h (target_resume): Extend comment.
gdb/testsuite/
2012-06-28 Jan Kratochvil <jan.kratochvil@redhat.com>
Pedro Alves <palves@redhat.com>
* gdb.threads/siginfo-threads.exp: New file.
* gdb.threads/siginfo-threads.c: New file.
* gdb.threads/sigstep-threads.exp: New file.
* gdb.threads/sigstep-threads.c: New file.
* common/linux-procfs.c (linux_proc_get_int): New, from
linux_proc_get_tgid, change its LWPID type to pid_t, add parameter
field.
(linux_proc_get_tgid): Only call linux_proc_get_int.
(linux_proc_get_tracerpid): New.
(linux_proc_pid_has_state): New, from linux_proc_pid_is_zombie.
(linux_proc_pid_is_stopped, linux_proc_pid_is_zombie): Only call
linux_proc_pid_has_state.
* common/linux-procfs.h (linux_proc_get_tracerpid): New declaration.
* common/linux-ptrace.c: Include linux-procfs.h and buffer.h.
(linux_ptrace_attach_warnings): New.
* common/linux-ptrace.h (struct buffer, linux_ptrace_attach_warnings):
New declaration.
* linux-nat.c: Include exceptions.h, linux-ptrace.h and buffer.h.
(linux_nat_attach): New variables ex, buffer, message and message_s.
Wrap to_attach by TRY_CATCH and call linux_ptrace_attach_warnings.
gdb/gdbserver/
* linux-low.c (linux_attach_lwp_1): New variable buffer. Call
linux_ptrace_attach_warnings.
gdb/testsuite/
* gdb.base/attach-twice.c: New files.
* gdb.base/attach-twice.exp: New files.
gdb/gdbserver/
* linux-low.c (pid_is_stopped): Delete, moved to common/.
(linux_attach_lwp_1): Adjust to use linux_proc_pid_is_stopped.
gdb/
* linux-nat.c (pid_is_stopped): Delete, moved to common/.
(linux_nat_post_attach_wait): Adjust to use
linux_proc_pid_is_stopped.
* common/linux-procfs.h (linux_proc_pid_is_stopped): Declare.
* common/linux-procfs.c (linux_proc_pid_is_stopped): New function,
based on pid_is_stopped from both linux-nat.c and
gdbserver/linux-low.c, and renamed.
symfile_flags.
* solib.c (solib_read_symbols): Use inferior's symfile_flags.
* linux-nat.c (linux_child_follow_fork): Set symfile_flags on
inferior.
* infrun.c (handle_vfork_child_exec_or_exit): Set symfile_flags on
inferior.
(follow_exec): Use inferior's symfile_flags.
* inferior.h (struct inferior) <symfile_flags>: New field.
Fix watchpoints across inferior fork.
* amd64-linux-nat.c (update_debug_registers_callback): Update the
comment for linux_nat_iterate_watchpoint_lwps.
(amd64_linux_dr_set_control, amd64_linux_dr_set_addr): Use
linux_nat_iterate_watchpoint_lwps.
(amd64_linux_prepare_to_resume): New comment on Linux kernel.
* i386-linux-nat.c (update_debug_registers_callback): Update the
comment for linux_nat_iterate_watchpoint_lwps.
(i386_linux_dr_set_control, i386_linux_dr_set_addr): Use
linux_nat_iterate_watchpoint_lwps.
(i386_linux_prepare_to_resume): New comment on Linux kernel.
* i386-nat.c: Include inferior.h.
(dr_mirror): Remove.
(i386_inferior_data, struct i386_inferior_data)
(i386_inferior_data_get): New.
(i386_debug_reg_state): Use i386_inferior_data_get.
(i386_cleanup_dregs, i386_update_inferior_debug_regs)
(i386_insert_watchpoint, i386_remove_watchpoint)
(i386_stopped_data_address, i386_insert_hw_breakpoint)
(i386_remove_hw_breakpoint): New variable state, use
i386_debug_reg_state instead of DR_MIRROR.
* linux-nat.c (delete_lwp): New declaration.
(num_lwps): Move here from downwards.
(delete_lwp_cleanup): New.
(linux_child_follow_fork): Create new child_lp, call
linux_nat_new_thread and linux_nat_prepare_to_resume before calling
PTRACE_DETACH.
(num_lwps): Move upwards.
(linux_nat_iterate_watchpoint_lwps): New.
* linux-nat.h (linux_nat_iterate_watchpoint_lwps_ftype): New.
(linux_nat_iterate_watchpoint_lwps_ftype): New declaration.
gdb/testsuite/
Fix watchpoints across inferior fork.
* gdb.threads/watchpoint-fork-child.c: New file.
* gdb.threads/watchpoint-fork-mt.c: New file.
* gdb.threads/watchpoint-fork-parent.c: New file.
* gdb.threads/watchpoint-fork-st.c: New file.
* gdb.threads/watchpoint-fork.exp: New file.
* gdb.threads/watchpoint-fork.h: New file.
* gdbarch.c, gdbarch.h: Regenerate.
* gcore.c (gcore_memory_sections): Try gdbarch find_memory_regions
callback before falling back to target method.
* linux-nat.c (read_mapping, linux_nat_find_memory_regions): Remove.
(linux_target_install_ops): No longer install it.
* linux-tdep.c (linux_find_memory_regions): New function.
(linux_init_abi): Install it.
* gdbarch.c, gdbarch.h: Regenerate.
* infcmd.c (info_proc_cmd_1): Try gdbarch info_proc callback
before falling back to the target info_proc callback.
* linux-nat.c: Do not include "cli/cli-utils.h".
(linux_nat_info_proc): Remove.
(linux_target_install_ops): No longer install it.
* linux-tdep.c: Include "cli/cli-utils.h" and <ctype.h>.
(read_mapping): New function.
(linux_info_proc): Likewise.
(linux_init_abi): Install it.
* linux-nat.c (linux_nat_close): Call linux_nat_is_async_p and
linux_nat_async directly instead of going through the target
vector.
* target.c (unpush_target): Close target after unpushing it, not
before.
Jan Kratochvil <jan.kratochvil@redhat.com>
* linux-nat.c (add_lwp): Don't call linux_nat_new_thread on the
first LWP.
* amd64-linux-nat.c (update_debug_registers_callback): Instantiate
`lwp->arch_private' if NULL.
(amd64_linux_prepare_to_resume): Do nothing if `lwp->arch_private'
is NULL.
* i386-linux-nat.c (update_debug_registers_callback): Instantiate
`lwp->arch_private' if NULL.
(i386_linux_prepare_to_resume): Do nothing if `lwp->arch_private'
is NULL.
gdb/
* linux-nat.c (linux_nat_filter_event): Remove `options'
parameter, and dead code that used it. If we're handling a
PTRACE_EVENT_EXEC event, and the thread group leader is no longer
in our lwp list, re-add it.
(check_zombie_leaders): New.
(linux_nat_wait_1): Remove `options' and `pid' locals. Always
wait for children with WNOHANG, and always wait for all children.
Don't check for no resumed children upfront. Simplify wait loop.
Check for zombie thread group leaders after handling all wait
statuses. Return TARGET_WAITKIND_NO_RESUMED if there no
unwaited-for children left.
* infrun.c (fetch_inferior_event): Handle TARGET_WAITKIND_NO_RESUMED.
(handle_inferior_event): Handle TARGET_WAITKIND_NO_RESUMED.
(normal_stop): Handle TARGET_WAITKIND_NO_RESUMED.
* target.h (enum target_waitkind) <TARGET_WAITKIND_NO_RESUMED>: New.
gdb/testsuite/
* gdb.threads/no-unwaited-for-left.c: New.
* gdb.threads/no-unwaited-for-left.exp: New.
* gdb.threads/non-ldr-exc-1.c: New.
* gdb.threads/non-ldr-exc-1.exp: New.
* gdb.threads/non-ldr-exc-2.c: New.
* gdb.threads/non-ldr-exc-2.exp: New.
* gdb.threads/non-ldr-exc-3.c: New.
* gdb.threads/non-ldr-exc-3.exp: New.
* gdb.threads/non-ldr-exc-4.c: New.
* gdb.threads/non-ldr-exc-4.exp: New.
gdb/
* linux-nat.c (linux_handle_extended_wait): When handling a clone
event, in non-stop, if not stopping, make sure the new lwp has
last_resume_kind set to resume_continue. Assert that when we're
resuming the new lwp, its last_resume_kind is resume_continue.
* linux-nat.c (linux_handle_extended_wait): Always dump both the
parent and child's pids as soon as we detect a clone event.
Adjust another debug message.
libthread_db when we load libpthread or the main symbol file.
(thread_db_inferior_created): New function.
(_initialize_thread_db): Attach inferior_created observer.
* linux-nat.c (linux_child_post_attach): Remove call to
check_for_thread_db.
(linux_child_post_startup_inferior): Ditto.
* objfiles.h (OBJF_MAINLINE): Define.
* symfile.c (symbol_file_add_with_addrs_or_offsets): Pass it to
allocate_objfile when appropriate.
gdb/
* linux-nat.c (linux_handle_extended_wait): Don't resume the new
new clone lwp if the core asked it to stop. Don't pass on
unexpected signals to the new clone; leave them pending instead.
gdb/
* linux-nat.c (linux_nat_wait_1): Copy the event lwp's
last_resume_kind before clearing it, and use the copy instead to
determine whether to report a SIGSTOP as TARGET_SIGNAL_0. Use
resume_clear_callback in the non-stop path too.
* infrun.c (disable_randomization): New global variable.
(show_disable_randomization): New function.
(set_disable_randomization): Likewise.
(_initialize_infrun): Install set/show disable-randomization
commands.
* linux-nat.c (disable_randomization): Remove.
(show_disable_randomization): Likewise.
(set_disable_randomization): Likewise.
(_initialize_linux_nat): No longer install set/show
disable-randomization commands here.
(linux_nat_supports_disable_randomization): New function.
(linux_nat_add_target): Install it.
* remote.c (PACKET_QDisableRandomization): New enum value.
(remote_protocol_packets): Support QDisableRandomization.
(_initialize_remote): Likewise.
(remote_supports_disable_randomization): New function.
(init_remote_ops): Install it.
(extended_remote_supports_disable_randomization): New function.
(init_extended_remote_ops): Install it.
(extended_remote_disable_randomization): New function.
(extended_remote_create_inferior_1): Call it.
* target.h (struct target_ops): Add to_supports_disable_randomization.
(target_supports_disable_randomization): Add prototype.
* target.c (target_supports_disable_randomization): New function.
(find_default_supports_disable_randomization): Likewise.
(init_dummy_target): Install it.
doc/
* gdb.texinfo (Starting your Program): "set disable-randomization"
is no longer Linux-specific.
(Remote Configuration): Document "set remote
disable-randomization-packet".
(General Query Packets): Document "QDisableRandomization" packet
and add it to "qSupported" list.
gdbserver/
* configure.ac: Check support for personality routine.
* configure: Regenerate.
* config.in: Likewise.
* linux-low.c: Include <sys/personality.h>.
Define ADDR_NO_RANDOMIZE if necessary.
(linux_create_inferior): Disable address space randomization when
forking inferior, if requested.
(linux_supports_disable_randomization): New function.
(linux_target_ops): Install it.
* server.h (disable_randomization): Declare.
* server.c (disable_randomization): New global variable.
(handle_general_set): Handle QDisableRandomization.
(handle_query): Likewise for qSupported.
(main): Support --disable-randomization and --no-disable-randomization
command line arguments.
* target.h (struct target_ops): Add supports_disable_randomization.
(target_supports_disable_randomization): New macro.
* linux-nat.h (enum resume_kind): New.
(struct lwp_info) <last_resume_kind>: New field.
(linux_child_follow_fork): Set last_resume_kind to resume_stop on
the new lwp.
(add_lwp): Set last_resume_kind as resume_continue by default.
(lin_lwp_attach_lwp): Set last_resume_kind as resume_stop.
(resume_lwp): New, factored out from resume_callback. Also check
for pending status in lp->waitstatus.
(resume_callback): Reimplement.
(resume_clear_callback): Set last_resume_kind as resume_stop.
(resume_set_callback): Set last_resume_kind as resume_continue.
(linux_nat_resume, linux_handle_extended_wait): Set
last_resume_kind.
(running_callback): Also check lp->waitstatus for pending events.
(select_singlestep_lwp_callback): Check that lp->last_resume_kind
is resume_step.
(stop_and_resume_callback): Don't re-resume if the core wanted the
lwp stopped. Use resume_lwp instead of resume_callback. Avoid
using an invalidated pointer.
(linux_nat_filter_event): Don't discard SIGSTOPs as delayed
SIGSTOPs if the core wanted the LWP to stop.
(linux_nat_wait_1) Don't consume a pending SIGSTOP if the core
wanted the lwp to stop. If the core wanted the lwp to stop, and
the lwp stopped with a SIGSTOP, report a TARGET_SIGNAL_0 instead
of TARGET_SIGNAL_STOP.
(linux_nat_stop_lwp): Don't synchronously wait for the lwp to stop
here. Instead, signal the lwp, and set the last_resume_kind to
resume_stop.