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binutils-gdb/gdb/aarch64-linux-nat.c
Pedro Alves 5b6d1e4fa4 Multi-target support 
This commit adds multi-target support to GDB.  What this means is that
with this commit, GDB can now be connected to different targets at the
same time.  E.g., you can debug a live native process and a core dump
at the same time, connect to multiple gdbservers, etc.

Actually, the word "target" is overloaded in gdb.  We already have a
target stack, with pushes several target_ops instances on top of one
another.  We also have "info target" already, which means something
completely different to what this patch does.

So from here on, I'll be using the "target connections" term, to mean
an open process_stratum target, pushed on a target stack.  This patch
makes gdb have multiple target stacks, and multiple process_stratum
targets open simultaneously.  The user-visible changes / commands will
also use this terminology, but of course it's all open to debate.

User-interface-wise, not that much changes.  The main difference is
that each inferior may have its own target connection.

A target connection (e.g., a target extended-remote connection) may
support debugging multiple processes, just as before.

Say you're debugging against gdbserver in extended-remote mode, and
you do "add-inferior" to prepare to spawn a new process, like:

 (gdb) target extended-remote :9999
 ...
 (gdb) start
 ...
 (gdb) add-inferior
 Added inferior 2
 (gdb) inferior 2
 [Switching to inferior 2 [<null>] (<noexec>)]
 (gdb) file a.out
 ...
 (gdb) start
 ...

At this point, you have two inferiors connected to the same gdbserver.

With this commit, GDB will maintain a target stack per inferior,
instead of a global target stack.

To preserve the behavior above, by default, "add-inferior" makes the
new inferior inherit a copy of the target stack of the current
inferior.  Same across a fork - the child inherits a copy of the
target stack of the parent.  While the target stacks are copied, the
targets themselves are not.  Instead, target_ops is made a
refcounted_object, which means that target_ops instances are
refcounted, which each inferior counting for a reference.

What if you want to create an inferior and connect it to some _other_
target?  For that, this commit introduces a new "add-inferior
-no-connection" option that makes the new inferior not share the
current inferior's target.  So you could do:

 (gdb) target extended-remote :9999
 Remote debugging using :9999
 ...
 (gdb) add-inferior -no-connection
 [New inferior 2]
 Added inferior 2
 (gdb) inferior 2
 [Switching to inferior 2 [<null>] (<noexec>)]
 (gdb) info inferiors
   Num  Description       Executable
   1    process 18401     target:/home/pedro/tmp/main
 * 2    <null>
 (gdb) tar extended-remote :10000
 Remote debugging using :10000
 ...
 (gdb) info inferiors
   Num  Description       Executable
   1    process 18401     target:/home/pedro/tmp/main
 * 2    process 18450     target:/home/pedro/tmp/main
 (gdb)

A following patch will extended "info inferiors" to include a column
indicating which connection an inferior is bound to, along with a
couple other UI tweaks.

Other than that, debugging is the same as before.  Users interact with
inferiors and threads as before.  The only difference is that
inferiors may be bound to processes running in different machines.

That's pretty much all there is to it in terms of noticeable UI
changes.

On to implementation.

Since we can be connected to different systems at the same time, a
ptid_t is no longer a unique identifier.  Instead a thread can be
identified by a pair of ptid_t and 'process_stratum_target *', the
later being the instance of the process_stratum target that owns the
process/thread.  Note that process_stratum_target inherits from
target_ops, and all process_stratum targets inherit from
process_stratum_target.  In earlier patches, many places in gdb were
converted to refer to threads by thread_info pointer instead of
ptid_t, but there are still places in gdb where we start with a
pid/tid and need to find the corresponding inferior or thread_info
objects.  So you'll see in the patch many places adding a
process_stratum_target parameter to functions that used to take only a
ptid_t.

Since each inferior has its own target stack now, we can always find
the process_stratum target for an inferior.  That is done via a
inf->process_target() convenience method.

Since each inferior has its own target stack, we need to handle the
"beneath" calls when servicing target calls.  The solution I settled
with is just to make sure to switch the current inferior to the
inferior you want before making a target call.  Not relying on global
context is just not feasible in current GDB.  Fortunately, there
aren't that many places that need to do that, because generally most
code that calls target methods already has the current context
pointing to the right inferior/thread.  Note, to emphasize -- there's
no method to "switch to this target stack".  Instead, you switch the
current inferior, and that implicitly switches the target stack.

In some spots, we need to iterate over all inferiors so that we reach
all target stacks.

Native targets are still singletons.  There's always only a single
instance of such targets.

Remote targets however, we'll have one instance per remote connection.

The exec target is still a singleton.  There's only one instance.  I
did not see the point of instanciating more than one exec_target
object.

After vfork, we need to make sure to push the exec target on the new
inferior.  See exec_on_vfork.

For type safety, functions that need a {target, ptid} pair to identify
a thread, take a process_stratum_target pointer for target parameter
instead of target_ops *.  Some shared code in gdb/nat/ also need to
gain a target pointer parameter.  This poses an issue, since gdbserver
doesn't have process_stratum_target, only target_ops.  To fix this,
this commit renames gdbserver's target_ops to process_stratum_target.
I think this makes sense.  There's no concept of target stack in
gdbserver, and gdbserver's target_ops really implements a
process_stratum-like target.

The thread and inferior iterator functions also gain
process_stratum_target parameters.  These are used to be able to
iterate over threads and inferiors of a given target.  Following usual
conventions, if the target pointer is null, then we iterate over
threads and inferiors of all targets.

I tried converting "add-inferior" to the gdb::option framework, as a
preparatory patch, but that stumbled on the fact that gdb::option does
not support file options yet, for "add-inferior -exec".  I have a WIP
patchset that adds that, but it's not a trivial patch, mainly due to
need to integrate readline's filename completion, so I deferred that
to some other time.

In infrun.c/infcmd.c, the main change is that we need to poll events
out of all targets.  See do_target_wait.  Right after collecting an
event, we switch the current inferior to an inferior bound to the
target that reported the event, so that target methods can be used
while handling the event.  This makes most of the code transparent to
multi-targets.  See fetch_inferior_event.

infrun.c:stop_all_threads is interesting -- in this function we need
to stop all threads of all targets.  What the function does is send an
asynchronous stop request to all threads, and then synchronously waits
for events, with target_wait, rinse repeat, until all it finds are
stopped threads.  Now that we have multiple targets, it's not
efficient to synchronously block in target_wait waiting for events out
of one target.  Instead, we implement a mini event loop, with
interruptible_select, select'ing on one file descriptor per target.
For this to work, we need to be able to ask the target for a waitable
file descriptor.  Such file descriptors already exist, they are the
descriptors registered in the main event loop with add_file_handler,
inside the target_async implementations.  This commit adds a new
target_async_wait_fd target method that just returns the file
descriptor in question.  See wait_one / stop_all_threads in infrun.c.

The 'threads_executing' global is made a per-target variable.  Since
it is only relevant to process_stratum_target targets, this is where
it is put, instead of in target_ops.

You'll notice that remote.c includes some FIXME notes.  These refer to
the fact that the global arrays that hold data for the remote packets
supported are still globals.  For example, if we connect to two
different servers/stubs, then each might support different remote
protocol features.  They might even be different architectures, like
e.g., one ARM baremetal stub, and a x86 gdbserver, to debug a
host/controller scenario as a single program.  That isn't going to
work correctly today, because of said globals.  I'm leaving fixing
that for another pass, since it does not appear to be trivial, and I'd
rather land the base work first.  It's already useful to be able to
debug multiple instances of the same server (e.g., a distributed
cluster, where you have full control over the servers installed), so I
think as is it's already reasonable incremental progress.

Current limitations:

 - You can only resume more that one target at the same time if all
   targets support asynchronous debugging, and support non-stop mode.
   It should be possible to support mixed all-stop + non-stop
   backends, but that is left for another time.  This means that
   currently in order to do multi-target with gdbserver you need to
   issue "maint set target-non-stop on".  I would like to make that
   mode be the default, but we're not there yet.  Note that I'm
   talking about how the target backend works, only.  User-visible
   all-stop mode works just fine.

 - As explained above, connecting to different remote servers at the
   same time is likely to produce bad results if they don't support the
   exact set of RSP features.

FreeBSD updates courtesy of John Baldwin.

gdb/ChangeLog:
2020-01-10  Pedro Alves  <palves@redhat.com>
	    John Baldwin  <jhb@FreeBSD.org>

	* aarch64-linux-nat.c
	(aarch64_linux_nat_target::thread_architecture): Adjust.
	* ada-tasks.c (print_ada_task_info): Adjust find_thread_ptid call.
	(task_command_1): Likewise.
	* aix-thread.c (sync_threadlists, aix_thread_target::resume)
	(aix_thread_target::wait, aix_thread_target::fetch_registers)
	(aix_thread_target::store_registers)
	(aix_thread_target::thread_alive): Adjust.
	* amd64-fbsd-tdep.c: Include "inferior.h".
	(amd64fbsd_get_thread_local_address): Pass down target.
	* amd64-linux-nat.c (ps_get_thread_area): Use ps_prochandle
	thread's gdbarch instead of target_gdbarch.
	* break-catch-sig.c (signal_catchpoint_print_it): Adjust call to
	get_last_target_status.
	* break-catch-syscall.c (print_it_catch_syscall): Likewise.
	* breakpoint.c (breakpoints_should_be_inserted_now): Consider all
	inferiors.
	(update_inserted_breakpoint_locations): Skip if inferiors with no
	execution.
	(update_global_location_list): When handling moribund locations,
	find representative inferior for location's pspace, and use thread
	count of its process_stratum target.
	* bsd-kvm.c (bsd_kvm_target_open): Pass target down.
	* bsd-uthread.c (bsd_uthread_target::wait): Use
	as_process_stratum_target and adjust thread_change_ptid and
	add_thread calls.
	(bsd_uthread_target::update_thread_list): Use
	as_process_stratum_target and adjust find_thread_ptid,
	thread_change_ptid and add_thread calls.
	* btrace.c (maint_btrace_packet_history_cmd): Adjust
	find_thread_ptid call.
	* corelow.c (add_to_thread_list): Adjust add_thread call.
	(core_target_open): Adjust add_thread_silent and thread_count
	calls.
	(core_target::pid_to_str): Adjust find_inferior_ptid call.
	* ctf.c (ctf_target_open): Adjust add_thread_silent call.
	* event-top.c (async_disconnect): Pop targets from all inferiors.
	* exec.c (add_target_sections): Push exec target on all inferiors
	sharing the program space.
	(remove_target_sections): Remove the exec target from all
	inferiors sharing the program space.
	(exec_on_vfork): New.
	* exec.h (exec_on_vfork): Declare.
	* fbsd-nat.c (fbsd_add_threads): Add fbsd_nat_target parameter.
	Pass it down.
	(fbsd_nat_target::update_thread_list): Adjust.
	(fbsd_nat_target::resume): Adjust.
	(fbsd_handle_debug_trap): Add fbsd_nat_target parameter.  Pass it
	down.
	(fbsd_nat_target::wait, fbsd_nat_target::post_attach): Adjust.
	* fbsd-tdep.c (fbsd_corefile_thread): Adjust
	get_thread_arch_regcache call.
	* fork-child.c (gdb_startup_inferior): Pass target down to
	startup_inferior and set_executing.
	* gdbthread.h (struct process_stratum_target): Forward declare.
	(add_thread, add_thread_silent, add_thread_with_info)
	(in_thread_list): Add process_stratum_target parameter.
	(find_thread_ptid(inferior*, ptid_t)): New overload.
	(find_thread_ptid, thread_change_ptid): Add process_stratum_target
	parameter.
	(all_threads()): Delete overload.
	(all_threads, all_non_exited_threads): Add process_stratum_target
	parameter.
	(all_threads_safe): Use brace initialization.
	(thread_count): Add process_stratum_target parameter.
	(set_resumed, set_running, set_stop_requested, set_executing)
	(threads_are_executing, finish_thread_state): Add
	process_stratum_target parameter.
	(switch_to_thread): Use is_current_thread.
	* i386-fbsd-tdep.c: Include "inferior.h".
	(i386fbsd_get_thread_local_address): Pass down target.
	* i386-linux-nat.c (i386_linux_nat_target::low_resume): Adjust.
	* inf-child.c (inf_child_target::maybe_unpush_target): Remove
	have_inferiors check.
	* inf-ptrace.c (inf_ptrace_target::create_inferior)
	(inf_ptrace_target::attach): Adjust.
	* infcall.c (run_inferior_call): Adjust.
	* infcmd.c (run_command_1): Pass target to
	scoped_finish_thread_state.
	(proceed_thread_callback): Skip inferiors with no execution.
	(continue_command): Rename 'all_threads' local to avoid hiding
	'all_threads' function.  Adjust get_last_target_status call.
	(prepare_one_step): Adjust set_running call.
	(signal_command): Use user_visible_resume_target.  Compare thread
	pointers instead of inferior_ptid.
	(info_program_command): Adjust to pass down target.
	(attach_command): Mark target's 'thread_executing' flag.
	(stop_current_target_threads_ns): New, factored out from ...
	(interrupt_target_1): ... this.  Switch inferior before making
	target calls.
	* inferior-iter.h
	(struct all_inferiors_iterator, struct all_inferiors_range)
	(struct all_inferiors_safe_range)
	(struct all_non_exited_inferiors_range): Filter on
	process_stratum_target too.  Remove explicit.
	* inferior.c (inferior::inferior): Push dummy target on target
	stack.
	(find_inferior_pid, find_inferior_ptid, number_of_live_inferiors):
	Add process_stratum_target parameter, and pass it down.
	(have_live_inferiors): Adjust.
	(switch_to_inferior_and_push_target): New.
	(add_inferior_command, clone_inferior_command): Handle
	"-no-connection" parameter.  Use
	switch_to_inferior_and_push_target.
	(_initialize_inferior): Mention "-no-connection" option in
	the help of "add-inferior" and "clone-inferior" commands.
	* inferior.h: Include "process-stratum-target.h".
	(interrupt_target_1): Use bool.
	(struct inferior) <push_target, unpush_target, target_is_pushed,
	find_target_beneath, top_target, process_target, target_at,
	m_stack>: New.
	(discard_all_inferiors): Delete.
	(find_inferior_pid, find_inferior_ptid, number_of_live_inferiors)
	(all_inferiors, all_non_exited_inferiors): Add
	process_stratum_target parameter.
	* infrun.c: Include "gdb_select.h" and <unordered_map>.
	(target_last_proc_target): New global.
	(follow_fork_inferior): Push target on new inferior.  Pass target
	to add_thread_silent.  Call exec_on_vfork.  Handle target's
	reference count.
	(follow_fork): Adjust get_last_target_status call.  Also consider
	target.
	(follow_exec): Push target on new inferior.
	(struct execution_control_state) <target>: New field.
	(user_visible_resume_target): New.
	(do_target_resume): Call target_async.
	(resume_1): Set target's threads_executing flag.  Consider resume
	target.
	(commit_resume_all_targets): New.
	(proceed): Also consider resume target.  Skip threads of inferiors
	with no execution.  Commit resumtion in all targets.
	(start_remote): Pass current inferior to wait_for_inferior.
	(infrun_thread_stop_requested): Consider target as well.  Pass
	thread_info pointer to clear_inline_frame_state instead of ptid.
	(infrun_thread_thread_exit): Consider target as well.
	(random_pending_event_thread): New inferior parameter.  Use it.
	(do_target_wait): Rename to ...
	(do_target_wait_1): ... this.  Add inferior parameter, and pass it
	down.
	(threads_are_resumed_pending_p, do_target_wait): New.
	(prepare_for_detach): Adjust calls.
	(wait_for_inferior): New inferior parameter.  Handle it.  Use
	do_target_wait_1 instead of do_target_wait.
	(fetch_inferior_event): Adjust.  Switch to representative
	inferior.  Pass target down.
	(set_last_target_status): Add process_stratum_target parameter.
	Save target in global.
	(get_last_target_status): Add process_stratum_target parameter and
	handle it.
	(nullify_last_target_wait_ptid): Clear 'target_last_proc_target'.
	(context_switch): Check inferior_ptid == null_ptid before calling
	inferior_thread().
	(get_inferior_stop_soon): Pass down target.
	(wait_one): Rename to ...
	(poll_one_curr_target): ... this.
	(struct wait_one_event): New.
	(wait_one): New.
	(stop_all_threads): Adjust.
	(handle_no_resumed, handle_inferior_event): Adjust to consider the
	event's target.
	(switch_back_to_stepped_thread): Also consider target.
	(print_stop_event): Update.
	(normal_stop): Update.  Also consider the resume target.
	* infrun.h (wait_for_inferior): Remove declaration.
	(user_visible_resume_target): New declaration.
	(get_last_target_status, set_last_target_status): New
	process_stratum_target parameter.
	* inline-frame.c (clear_inline_frame_state(ptid_t)): Add
	process_stratum_target parameter, and use it.
	(clear_inline_frame_state (thread_info*)): New.
	* inline-frame.c (clear_inline_frame_state(ptid_t)): Add
	process_stratum_target parameter.
	(clear_inline_frame_state (thread_info*)): Declare.
	* linux-fork.c (delete_checkpoint_command): Pass target down to
	find_thread_ptid.
	(checkpoint_command): Adjust.
	* linux-nat.c (linux_nat_target::follow_fork): Switch to thread
	instead of just tweaking inferior_ptid.
	(linux_nat_switch_fork): Pass target down to thread_change_ptid.
	(exit_lwp): Pass target down to find_thread_ptid.
	(attach_proc_task_lwp_callback): Pass target down to
	add_thread/set_running/set_executing.
	(linux_nat_target::attach): Pass target down to
	thread_change_ptid.
	(get_detach_signal): Pass target down to find_thread_ptid.
	Consider last target status's target.
	(linux_resume_one_lwp_throw, resume_lwp)
	(linux_handle_syscall_trap, linux_handle_extended_wait, wait_lwp)
	(stop_wait_callback, save_stop_reason, linux_nat_filter_event)
	(linux_nat_wait_1, resume_stopped_resumed_lwps): Pass target down.
	(linux_nat_target::async_wait_fd): New.
	(linux_nat_stop_lwp, linux_nat_target::thread_address_space): Pass
	target down.
	* linux-nat.h (linux_nat_target::async_wait_fd): Declare.
	* linux-tdep.c (get_thread_arch_regcache): Pass target down.
	* linux-thread-db.c (struct thread_db_info::process_target): New
	field.
	(add_thread_db_info): Save target.
	(get_thread_db_info): New process_stratum_target parameter.  Also
	match target.
	(delete_thread_db_info): New process_stratum_target parameter.
	Also match target.
	(thread_from_lwp): Adjust to pass down target.
	(thread_db_notice_clone): Pass down target.
	(check_thread_db_callback): Pass down target.
	(try_thread_db_load_1): Always push the thread_db target.
	(try_thread_db_load, record_thread): Pass target down.
	(thread_db_target::detach): Pass target down.  Always unpush the
	thread_db target.
	(thread_db_target::wait, thread_db_target::mourn_inferior): Pass
	target down.  Always unpush the thread_db target.
	(find_new_threads_callback, thread_db_find_new_threads_2)
	(thread_db_target::update_thread_list): Pass target down.
	(thread_db_target::pid_to_str): Pass current inferior down.
	(thread_db_target::get_thread_local_address): Pass target down.
	(thread_db_target::resume, maintenance_check_libthread_db): Pass
	target down.
	* nto-procfs.c (nto_procfs_target::update_thread_list): Adjust.
	* procfs.c (procfs_target::procfs_init_inferior): Declare.
	(proc_set_current_signal, do_attach, procfs_target::wait): Adjust.
	(procfs_init_inferior): Rename to ...
	(procfs_target::procfs_init_inferior): ... this and adjust.
	(procfs_target::create_inferior, procfs_notice_thread)
	(procfs_do_thread_registers): Adjust.
	* ppc-fbsd-tdep.c: Include "inferior.h".
	(ppcfbsd_get_thread_local_address): Pass down target.
	* proc-service.c (ps_xfer_memory): Switch current inferior and
	program space as well.
	(get_ps_regcache): Pass target down.
	* process-stratum-target.c
	(process_stratum_target::thread_address_space)
	(process_stratum_target::thread_architecture): Pass target down.
	* process-stratum-target.h
	(process_stratum_target::threads_executing): New field.
	(as_process_stratum_target): New.
	* ravenscar-thread.c
	(ravenscar_thread_target::update_inferior_ptid): Pass target down.
	(ravenscar_thread_target::wait, ravenscar_add_thread): Pass target
	down.
	* record-btrace.c (record_btrace_target::info_record): Adjust.
	(record_btrace_target::record_method)
	(record_btrace_target::record_is_replaying)
	(record_btrace_target::fetch_registers)
	(get_thread_current_frame_id, record_btrace_target::resume)
	(record_btrace_target::wait, record_btrace_target::stop): Pass
	target down.
	* record-full.c (record_full_wait_1): Switch to event thread.
	Pass target down.
	* regcache.c (regcache::regcache)
	(get_thread_arch_aspace_regcache, get_thread_arch_regcache): Add
	process_stratum_target parameter and handle it.
	(current_thread_target): New global.
	(get_thread_regcache): Add process_stratum_target parameter and
	handle it.  Switch inferior before calling target method.
	(get_thread_regcache): Pass target down.
	(get_thread_regcache_for_ptid): Pass target down.
	(registers_changed_ptid): Add process_stratum_target parameter and
	handle it.
	(registers_changed_thread, registers_changed): Pass target down.
	(test_get_thread_arch_aspace_regcache): New.
	(current_regcache_test): Define a couple local test_target_ops
	instances and use them for testing.
	(readwrite_regcache): Pass process_stratum_target parameter.
	(cooked_read_test, cooked_write_test): Pass mock_target down.
	* regcache.h (get_thread_regcache, get_thread_arch_regcache)
	(get_thread_arch_aspace_regcache): Add process_stratum_target
	parameter.
	(regcache::target): New method.
	(regcache::regcache, regcache::get_thread_arch_aspace_regcache)
	(regcache::registers_changed_ptid): Add process_stratum_target
	parameter.
	(regcache::m_target): New field.
	(registers_changed_ptid): Add process_stratum_target parameter.
	* remote.c (remote_state::supports_vCont_probed): New field.
	(remote_target::async_wait_fd): New method.
	(remote_unpush_and_throw): Add remote_target parameter.
	(get_current_remote_target): Adjust.
	(remote_target::remote_add_inferior): Push target.
	(remote_target::remote_add_thread)
	(remote_target::remote_notice_new_inferior)
	(get_remote_thread_info): Pass target down.
	(remote_target::update_thread_list): Skip threads of inferiors
	bound to other targets.  (remote_target::close): Don't discard
	inferiors.  (remote_target::add_current_inferior_and_thread)
	(remote_target::process_initial_stop_replies)
	(remote_target::start_remote)
	(remote_target::remote_serial_quit_handler): Pass down target.
	(remote_target::remote_unpush_target): New remote_target
	parameter.  Unpush the target from all inferiors.
	(remote_target::remote_unpush_and_throw): New remote_target
	parameter.  Pass it down.
	(remote_target::open_1): Check whether the current inferior has
	execution instead of checking whether any inferior is live.  Pass
	target down.
	(remote_target::remote_detach_1): Pass down target.  Use
	remote_unpush_target.
	(extended_remote_target::attach): Pass down target.
	(remote_target::remote_vcont_probe): Set supports_vCont_probed.
	(remote_target::append_resumption): Pass down target.
	(remote_target::append_pending_thread_resumptions)
	(remote_target::remote_resume_with_hc, remote_target::resume)
	(remote_target::commit_resume): Pass down target.
	(remote_target::remote_stop_ns): Check supports_vCont_probed.
	(remote_target::interrupt_query)
	(remote_target::remove_new_fork_children)
	(remote_target::check_pending_events_prevent_wildcard_vcont)
	(remote_target::remote_parse_stop_reply)
	(remote_target::process_stop_reply): Pass down target.
	(first_remote_resumed_thread): New remote_target parameter.  Pass
	it down.
	(remote_target::wait_as): Pass down target.
	(unpush_and_perror): New remote_target parameter.  Pass it down.
	(remote_target::readchar, remote_target::remote_serial_write)
	(remote_target::getpkt_or_notif_sane_1)
	(remote_target::kill_new_fork_children, remote_target::kill): Pass
	down target.
	(remote_target::mourn_inferior): Pass down target.  Use
	remote_unpush_target.
	(remote_target::core_of_thread)
	(remote_target::remote_btrace_maybe_reopen): Pass down target.
	(remote_target::pid_to_exec_file)
	(remote_target::thread_handle_to_thread_info): Pass down target.
	(remote_target::async_wait_fd): New.
	* riscv-fbsd-tdep.c: Include "inferior.h".
	(riscv_fbsd_get_thread_local_address): Pass down target.
	* sol2-tdep.c (sol2_core_pid_to_str): Pass down target.
	* sol-thread.c (sol_thread_target::wait, ps_lgetregs, ps_lsetregs)
	(ps_lgetfpregs, ps_lsetfpregs, sol_update_thread_list_callback):
	Adjust.
	* solib-spu.c (spu_skip_standalone_loader): Pass down target.
	* solib-svr4.c (enable_break): Pass down target.
	* spu-multiarch.c (parse_spufs_run): Pass down target.
	* spu-tdep.c (spu2ppu_sniffer): Pass down target.
	* target-delegates.c: Regenerate.
	* target.c (g_target_stack): Delete.
	(current_top_target): Return the current inferior's top target.
	(target_has_execution_1): Refer to the passed-in inferior's top
	target.
	(target_supports_terminal_ours): Check whether the initial
	inferior was already created.
	(decref_target): New.
	(target_stack::push): Incref/decref the target.
	(push_target, push_target, unpush_target): Adjust.
	(target_stack::unpush): Defref target.
	(target_is_pushed): Return bool.  Adjust to refer to the current
	inferior's target stack.
	(dispose_inferior): Delete, and inline parts ...
	(target_preopen): ... here.  Only dispose of the current inferior.
	(target_detach): Hold strong target reference while detaching.
	Pass target down.
	(target_thread_name): Add assertion.
	(target_resume): Pass down target.
	(target_ops::beneath, find_target_at): Adjust to refer to the
	current inferior's target stack.
	(get_dummy_target): New.
	(target_pass_ctrlc): Pass the Ctrl-C to the first inferior that
	has a thread running.
	(initialize_targets): Rename to ...
	(_initialize_target): ... this.
	* target.h: Include "gdbsupport/refcounted-object.h".
	(struct target_ops): Inherit refcounted_object.
	(target_ops::shortname, target_ops::longname): Make const.
	(target_ops::async_wait_fd): New method.
	(decref_target): Declare.
	(struct target_ops_ref_policy): New.
	(target_ops_ref): New typedef.
	(get_dummy_target): Declare function.
	(target_is_pushed): Return bool.
	* thread-iter.c (all_matching_threads_iterator::m_inf_matches)
	(all_matching_threads_iterator::all_matching_threads_iterator):
	Handle filter target.
	* thread-iter.h (struct all_matching_threads_iterator, struct
	all_matching_threads_range, class all_non_exited_threads_range):
	Filter by target too.  Remove explicit.
	* thread.c (threads_executing): Delete.
	(inferior_thread): Pass down current inferior.
	(clear_thread_inferior_resources): Pass down thread pointer
	instead of ptid_t.
	(add_thread_silent, add_thread_with_info, add_thread): Add
	process_stratum_target parameter.  Use it for thread and inferior
	searches.
	(is_current_thread): New.
	(thread_info::deletable): Use it.
	(find_thread_ptid, thread_count, in_thread_list)
	(thread_change_ptid, set_resumed, set_running): New
	process_stratum_target parameter.  Pass it down.
	(set_executing): New process_stratum_target parameter.  Pass it
	down.  Adjust reference to 'threads_executing'.
	(threads_are_executing): New process_stratum_target parameter.
	Adjust reference to 'threads_executing'.
	(set_stop_requested, finish_thread_state): New
	process_stratum_target parameter.  Pass it down.
	(switch_to_thread): Also match inferior.
	(switch_to_thread): New process_stratum_target parameter.  Pass it
	down.
	(update_threads_executing): Reimplement.
	* top.c (quit_force): Pop targets from all inferior.
	(gdb_init): Don't call initialize_targets.
	* windows-nat.c (windows_nat_target) <get_windows_debug_event>:
	Declare.
	(windows_add_thread, windows_delete_thread): Adjust.
	(get_windows_debug_event): Rename to ...
	(windows_nat_target::get_windows_debug_event): ... this.  Adjust.
	* tracefile-tfile.c (tfile_target_open): Pass down target.
	* gdbsupport/common-gdbthread.h (struct process_stratum_target):
	Forward declare.
	(switch_to_thread): Add process_stratum_target parameter.
	* mi/mi-interp.c (mi_on_resume_1): Add process_stratum_target
	parameter.  Use it.
	(mi_on_resume): Pass target down.
	* nat/fork-inferior.c (startup_inferior): Add
	process_stratum_target parameter.  Pass it down.
	* nat/fork-inferior.h (startup_inferior): Add
	process_stratum_target parameter.
	* python/py-threadevent.c (py_get_event_thread): Pass target down.

gdb/gdbserver/ChangeLog:
2020-01-10  Pedro Alves  <palves@redhat.com>

	* fork-child.c (post_fork_inferior): Pass target down to
	startup_inferior.
	* inferiors.c (switch_to_thread): Add process_stratum_target
	parameter.
	* lynx-low.c (lynx_target_ops): Now a process_stratum_target.
	* nto-low.c (nto_target_ops): Now a process_stratum_target.
	* linux-low.c (linux_target_ops): Now a process_stratum_target.
	* remote-utils.c (prepare_resume_reply): Pass the target to
	switch_to_thread.
	* target.c (the_target): Now a process_stratum_target.
	(done_accessing_memory): Pass the target to switch_to_thread.
	(set_target_ops): Ajust to use process_stratum_target.
	* target.h (struct target_ops): Rename to ...
	(struct process_stratum_target): ... this.
	(the_target, set_target_ops): Adjust.
	(prepare_to_access_memory): Adjust comment.
	* win32-low.c (child_xfer_memory): Adjust to use
	process_stratum_target.
	(win32_target_ops): Now a process_stratum_target.
2020-01-10 20:06:08 +00:00

1008 lines
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/* Native-dependent code for GNU/Linux AArch64.
Copyright (C) 2011-2020 Free Software Foundation, Inc.
Contributed by ARM Ltd.
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 "inferior.h"
#include "gdbcore.h"
#include "regcache.h"
#include "linux-nat.h"
#include "target-descriptions.h"
#include "auxv.h"
#include "gdbcmd.h"
#include "aarch64-tdep.h"
#include "aarch64-linux-tdep.h"
#include "aarch32-linux-nat.h"
#include "aarch32-tdep.h"
#include "arch/arm.h"
#include "nat/aarch64-linux.h"
#include "nat/aarch64-linux-hw-point.h"
#include "nat/aarch64-sve-linux-ptrace.h"
#include "elf/external.h"
#include "elf/common.h"
#include "nat/gdb_ptrace.h"
#include <sys/utsname.h>
#include <asm/ptrace.h>
#include "gregset.h"
#include "linux-tdep.h"
/* Defines ps_err_e, struct ps_prochandle. */
#include "gdb_proc_service.h"
#include "arch-utils.h"
#ifndef TRAP_HWBKPT
#define TRAP_HWBKPT 0x0004
#endif
class aarch64_linux_nat_target final : public linux_nat_target
{
public:
/* Add our register access methods. */
void fetch_registers (struct regcache *, int) override;
void store_registers (struct regcache *, int) override;
const struct target_desc *read_description () override;
/* Add our hardware breakpoint and watchpoint implementation. */
int can_use_hw_breakpoint (enum bptype, int, int) override;
int insert_hw_breakpoint (struct gdbarch *, struct bp_target_info *) override;
int remove_hw_breakpoint (struct gdbarch *, struct bp_target_info *) override;
int region_ok_for_hw_watchpoint (CORE_ADDR, int) override;
int insert_watchpoint (CORE_ADDR, int, enum target_hw_bp_type,
struct expression *) override;
int remove_watchpoint (CORE_ADDR, int, enum target_hw_bp_type,
struct expression *) override;
bool stopped_by_watchpoint () override;
bool stopped_data_address (CORE_ADDR *) override;
bool watchpoint_addr_within_range (CORE_ADDR, CORE_ADDR, int) override;
int can_do_single_step () override;
/* Override the GNU/Linux inferior startup hook. */
void post_startup_inferior (ptid_t) override;
/* Override the GNU/Linux post attach hook. */
void post_attach (int pid) override;
/* These three defer to common nat/ code. */
void low_new_thread (struct lwp_info *lp) override
{ aarch64_linux_new_thread (lp); }
void low_delete_thread (struct arch_lwp_info *lp) override
{ aarch64_linux_delete_thread (lp); }
void low_prepare_to_resume (struct lwp_info *lp) override
{ aarch64_linux_prepare_to_resume (lp); }
void low_new_fork (struct lwp_info *parent, pid_t child_pid) override;
void low_forget_process (pid_t pid) override;
/* Add our siginfo layout converter. */
bool low_siginfo_fixup (siginfo_t *ptrace, gdb_byte *inf, int direction)
override;
struct gdbarch *thread_architecture (ptid_t) override;
};
static aarch64_linux_nat_target the_aarch64_linux_nat_target;
/* Per-process data. We don't bind this to a per-inferior registry
because of targets like x86 GNU/Linux that need to keep track of
processes that aren't bound to any inferior (e.g., fork children,
checkpoints). */
struct aarch64_process_info
{
/* Linked list. */
struct aarch64_process_info *next;
/* The process identifier. */
pid_t pid;
/* Copy of aarch64 hardware debug registers. */
struct aarch64_debug_reg_state state;
};
static struct aarch64_process_info *aarch64_process_list = NULL;
/* Find process data for process PID. */
static struct aarch64_process_info *
aarch64_find_process_pid (pid_t pid)
{
struct aarch64_process_info *proc;
for (proc = aarch64_process_list; proc; proc = proc->next)
if (proc->pid == pid)
return proc;
return NULL;
}
/* Add process data for process PID. Returns newly allocated info
object. */
static struct aarch64_process_info *
aarch64_add_process (pid_t pid)
{
struct aarch64_process_info *proc;
proc = XCNEW (struct aarch64_process_info);
proc->pid = pid;
proc->next = aarch64_process_list;
aarch64_process_list = proc;
return proc;
}
/* Get data specific info for process PID, creating it if necessary.
Never returns NULL. */
static struct aarch64_process_info *
aarch64_process_info_get (pid_t pid)
{
struct aarch64_process_info *proc;
proc = aarch64_find_process_pid (pid);
if (proc == NULL)
proc = aarch64_add_process (pid);
return proc;
}
/* Called whenever GDB is no longer debugging process PID. It deletes
data structures that keep track of debug register state. */
void
aarch64_linux_nat_target::low_forget_process (pid_t pid)
{
struct aarch64_process_info *proc, **proc_link;
proc = aarch64_process_list;
proc_link = &aarch64_process_list;
while (proc != NULL)
{
if (proc->pid == pid)
{
*proc_link = proc->next;
xfree (proc);
return;
}
proc_link = &proc->next;
proc = *proc_link;
}
}
/* Get debug registers state for process PID. */
struct aarch64_debug_reg_state *
aarch64_get_debug_reg_state (pid_t pid)
{
return &aarch64_process_info_get (pid)->state;
}
/* Fill GDB's register array with the general-purpose register values
from the current thread. */
static void
fetch_gregs_from_thread (struct regcache *regcache)
{
int ret, tid;
struct gdbarch *gdbarch = regcache->arch ();
elf_gregset_t regs;
struct iovec iovec;
/* Make sure REGS can hold all registers contents on both aarch64
and arm. */
gdb_static_assert (sizeof (regs) >= 18 * 4);
tid = regcache->ptid ().lwp ();
iovec.iov_base = &regs;
if (gdbarch_bfd_arch_info (gdbarch)->bits_per_word == 32)
iovec.iov_len = 18 * 4;
else
iovec.iov_len = sizeof (regs);
ret = ptrace (PTRACE_GETREGSET, tid, NT_PRSTATUS, &iovec);
if (ret < 0)
perror_with_name (_("Unable to fetch general registers."));
if (gdbarch_bfd_arch_info (gdbarch)->bits_per_word == 32)
aarch32_gp_regcache_supply (regcache, (uint32_t *) regs, 1);
else
{
int regno;
for (regno = AARCH64_X0_REGNUM; regno <= AARCH64_CPSR_REGNUM; regno++)
regcache->raw_supply (regno, &regs[regno - AARCH64_X0_REGNUM]);
}
}
/* Store to the current thread the valid general-purpose register
values in the GDB's register array. */
static void
store_gregs_to_thread (const struct regcache *regcache)
{
int ret, tid;
elf_gregset_t regs;
struct iovec iovec;
struct gdbarch *gdbarch = regcache->arch ();
/* Make sure REGS can hold all registers contents on both aarch64
and arm. */
gdb_static_assert (sizeof (regs) >= 18 * 4);
tid = regcache->ptid ().lwp ();
iovec.iov_base = &regs;
if (gdbarch_bfd_arch_info (gdbarch)->bits_per_word == 32)
iovec.iov_len = 18 * 4;
else
iovec.iov_len = sizeof (regs);
ret = ptrace (PTRACE_GETREGSET, tid, NT_PRSTATUS, &iovec);
if (ret < 0)
perror_with_name (_("Unable to fetch general registers."));
if (gdbarch_bfd_arch_info (gdbarch)->bits_per_word == 32)
aarch32_gp_regcache_collect (regcache, (uint32_t *) regs, 1);
else
{
int regno;
for (regno = AARCH64_X0_REGNUM; regno <= AARCH64_CPSR_REGNUM; regno++)
if (REG_VALID == regcache->get_register_status (regno))
regcache->raw_collect (regno, &regs[regno - AARCH64_X0_REGNUM]);
}
ret = ptrace (PTRACE_SETREGSET, tid, NT_PRSTATUS, &iovec);
if (ret < 0)
perror_with_name (_("Unable to store general registers."));
}
/* Fill GDB's register array with the fp/simd register values
from the current thread. */
static void
fetch_fpregs_from_thread (struct regcache *regcache)
{
int ret, tid;
elf_fpregset_t regs;
struct iovec iovec;
struct gdbarch *gdbarch = regcache->arch ();
/* Make sure REGS can hold all VFP registers contents on both aarch64
and arm. */
gdb_static_assert (sizeof regs >= ARM_VFP3_REGS_SIZE);
tid = regcache->ptid ().lwp ();
iovec.iov_base = &regs;
if (gdbarch_bfd_arch_info (gdbarch)->bits_per_word == 32)
{
iovec.iov_len = ARM_VFP3_REGS_SIZE;
ret = ptrace (PTRACE_GETREGSET, tid, NT_ARM_VFP, &iovec);
if (ret < 0)
perror_with_name (_("Unable to fetch VFP registers."));
aarch32_vfp_regcache_supply (regcache, (gdb_byte *) &regs, 32);
}
else
{
int regno;
iovec.iov_len = sizeof (regs);
ret = ptrace (PTRACE_GETREGSET, tid, NT_FPREGSET, &iovec);
if (ret < 0)
perror_with_name (_("Unable to fetch vFP/SIMD registers."));
for (regno = AARCH64_V0_REGNUM; regno <= AARCH64_V31_REGNUM; regno++)
regcache->raw_supply (regno, &regs.vregs[regno - AARCH64_V0_REGNUM]);
regcache->raw_supply (AARCH64_FPSR_REGNUM, &regs.fpsr);
regcache->raw_supply (AARCH64_FPCR_REGNUM, &regs.fpcr);
}
}
/* Store to the current thread the valid fp/simd register
values in the GDB's register array. */
static void
store_fpregs_to_thread (const struct regcache *regcache)
{
int ret, tid;
elf_fpregset_t regs;
struct iovec iovec;
struct gdbarch *gdbarch = regcache->arch ();
/* Make sure REGS can hold all VFP registers contents on both aarch64
and arm. */
gdb_static_assert (sizeof regs >= ARM_VFP3_REGS_SIZE);
tid = regcache->ptid ().lwp ();
iovec.iov_base = &regs;
if (gdbarch_bfd_arch_info (gdbarch)->bits_per_word == 32)
{
iovec.iov_len = ARM_VFP3_REGS_SIZE;
ret = ptrace (PTRACE_GETREGSET, tid, NT_ARM_VFP, &iovec);
if (ret < 0)
perror_with_name (_("Unable to fetch VFP registers."));
aarch32_vfp_regcache_collect (regcache, (gdb_byte *) &regs, 32);
}
else
{
int regno;
iovec.iov_len = sizeof (regs);
ret = ptrace (PTRACE_GETREGSET, tid, NT_FPREGSET, &iovec);
if (ret < 0)
perror_with_name (_("Unable to fetch FP/SIMD registers."));
for (regno = AARCH64_V0_REGNUM; regno <= AARCH64_V31_REGNUM; regno++)
if (REG_VALID == regcache->get_register_status (regno))
regcache->raw_collect
(regno, (char *) &regs.vregs[regno - AARCH64_V0_REGNUM]);
if (REG_VALID == regcache->get_register_status (AARCH64_FPSR_REGNUM))
regcache->raw_collect (AARCH64_FPSR_REGNUM, (char *) &regs.fpsr);
if (REG_VALID == regcache->get_register_status (AARCH64_FPCR_REGNUM))
regcache->raw_collect (AARCH64_FPCR_REGNUM, (char *) &regs.fpcr);
}
if (gdbarch_bfd_arch_info (gdbarch)->bits_per_word == 32)
{
ret = ptrace (PTRACE_SETREGSET, tid, NT_ARM_VFP, &iovec);
if (ret < 0)
perror_with_name (_("Unable to store VFP registers."));
}
else
{
ret = ptrace (PTRACE_SETREGSET, tid, NT_FPREGSET, &iovec);
if (ret < 0)
perror_with_name (_("Unable to store FP/SIMD registers."));
}
}
/* Fill GDB's register array with the sve register values
from the current thread. */
static void
fetch_sveregs_from_thread (struct regcache *regcache)
{
std::unique_ptr<gdb_byte[]> base
= aarch64_sve_get_sveregs (regcache->ptid ().lwp ());
aarch64_sve_regs_copy_to_reg_buf (regcache, base.get ());
}
/* Store to the current thread the valid sve register
values in the GDB's register array. */
static void
store_sveregs_to_thread (struct regcache *regcache)
{
int ret;
struct iovec iovec;
int tid = regcache->ptid ().lwp ();
/* First store vector length to the thread. This is done first to ensure the
ptrace buffers read from the kernel are the correct size. */
if (!aarch64_sve_set_vq (tid, regcache))
perror_with_name (_("Unable to set VG register."));
/* Obtain a dump of SVE registers from ptrace. */
std::unique_ptr<gdb_byte[]> base = aarch64_sve_get_sveregs (tid);
/* Overwrite with regcache state. */
aarch64_sve_regs_copy_from_reg_buf (regcache, base.get ());
/* Write back to the kernel. */
iovec.iov_base = base.get ();
iovec.iov_len = ((struct user_sve_header *) base.get ())->size;
ret = ptrace (PTRACE_SETREGSET, tid, NT_ARM_SVE, &iovec);
if (ret < 0)
perror_with_name (_("Unable to store sve registers"));
}
/* Fill GDB's register array with the pointer authentication mask values from
the current thread. */
static void
fetch_pauth_masks_from_thread (struct regcache *regcache)
{
struct gdbarch_tdep *tdep = gdbarch_tdep (regcache->arch ());
int ret;
struct iovec iovec;
uint64_t pauth_regset[2] = {0, 0};
int tid = regcache->ptid ().lwp ();
iovec.iov_base = &pauth_regset;
iovec.iov_len = sizeof (pauth_regset);
ret = ptrace (PTRACE_GETREGSET, tid, NT_ARM_PAC_MASK, &iovec);
if (ret != 0)
perror_with_name (_("unable to fetch pauth registers."));
regcache->raw_supply (AARCH64_PAUTH_DMASK_REGNUM (tdep->pauth_reg_base),
&pauth_regset[0]);
regcache->raw_supply (AARCH64_PAUTH_CMASK_REGNUM (tdep->pauth_reg_base),
&pauth_regset[1]);
}
/* Implement the "fetch_registers" target_ops method. */
void
aarch64_linux_nat_target::fetch_registers (struct regcache *regcache,
int regno)
{
struct gdbarch_tdep *tdep = gdbarch_tdep (regcache->arch ());
if (regno == -1)
{
fetch_gregs_from_thread (regcache);
if (tdep->has_sve ())
fetch_sveregs_from_thread (regcache);
else
fetch_fpregs_from_thread (regcache);
if (tdep->has_pauth ())
fetch_pauth_masks_from_thread (regcache);
}
else if (regno < AARCH64_V0_REGNUM)
fetch_gregs_from_thread (regcache);
else if (tdep->has_sve ())
fetch_sveregs_from_thread (regcache);
else
fetch_fpregs_from_thread (regcache);
if (tdep->has_pauth ())
{
if (regno == AARCH64_PAUTH_DMASK_REGNUM (tdep->pauth_reg_base)
|| regno == AARCH64_PAUTH_CMASK_REGNUM (tdep->pauth_reg_base))
fetch_pauth_masks_from_thread (regcache);
}
}
/* Implement the "store_registers" target_ops method. */
void
aarch64_linux_nat_target::store_registers (struct regcache *regcache,
int regno)
{
struct gdbarch_tdep *tdep = gdbarch_tdep (regcache->arch ());
if (regno == -1)
{
store_gregs_to_thread (regcache);
if (tdep->has_sve ())
store_sveregs_to_thread (regcache);
else
store_fpregs_to_thread (regcache);
}
else if (regno < AARCH64_V0_REGNUM)
store_gregs_to_thread (regcache);
else if (tdep->has_sve ())
store_sveregs_to_thread (regcache);
else
store_fpregs_to_thread (regcache);
}
/* Fill register REGNO (if it is a general-purpose register) in
*GREGSETPS with the value in GDB's register array. If REGNO is -1,
do this for all registers. */
void
fill_gregset (const struct regcache *regcache,
gdb_gregset_t *gregsetp, int regno)
{
regcache_collect_regset (&aarch64_linux_gregset, regcache,
regno, (gdb_byte *) gregsetp,
AARCH64_LINUX_SIZEOF_GREGSET);
}
/* Fill GDB's register array with the general-purpose register values
in *GREGSETP. */
void
supply_gregset (struct regcache *regcache, const gdb_gregset_t *gregsetp)
{
regcache_supply_regset (&aarch64_linux_gregset, regcache, -1,
(const gdb_byte *) gregsetp,
AARCH64_LINUX_SIZEOF_GREGSET);
}
/* Fill register REGNO (if it is a floating-point register) in
*FPREGSETP with the value in GDB's register array. If REGNO is -1,
do this for all registers. */
void
fill_fpregset (const struct regcache *regcache,
gdb_fpregset_t *fpregsetp, int regno)
{
regcache_collect_regset (&aarch64_linux_fpregset, regcache,
regno, (gdb_byte *) fpregsetp,
AARCH64_LINUX_SIZEOF_FPREGSET);
}
/* Fill GDB's register array with the floating-point register values
in *FPREGSETP. */
void
supply_fpregset (struct regcache *regcache, const gdb_fpregset_t *fpregsetp)
{
regcache_supply_regset (&aarch64_linux_fpregset, regcache, -1,
(const gdb_byte *) fpregsetp,
AARCH64_LINUX_SIZEOF_FPREGSET);
}
/* linux_nat_new_fork hook. */
void
aarch64_linux_nat_target::low_new_fork (struct lwp_info *parent,
pid_t child_pid)
{
pid_t parent_pid;
struct aarch64_debug_reg_state *parent_state;
struct aarch64_debug_reg_state *child_state;
/* NULL means no watchpoint has ever been set in the parent. In
that case, there's nothing to do. */
if (parent->arch_private == NULL)
return;
/* GDB core assumes the child inherits the watchpoints/hw
breakpoints of the parent, and will remove them all from the
forked off process. Copy the debug registers mirrors into the
new process so that all breakpoints and watchpoints can be
removed together. */
parent_pid = parent->ptid.pid ();
parent_state = aarch64_get_debug_reg_state (parent_pid);
child_state = aarch64_get_debug_reg_state (child_pid);
*child_state = *parent_state;
}
/* Called by libthread_db. Returns a pointer to the thread local
storage (or its descriptor). */
ps_err_e
ps_get_thread_area (struct ps_prochandle *ph,
lwpid_t lwpid, int idx, void **base)
{
int is_64bit_p
= (gdbarch_bfd_arch_info (target_gdbarch ())->bits_per_word == 64);
return aarch64_ps_get_thread_area (ph, lwpid, idx, base, is_64bit_p);
}
/* Implement the "post_startup_inferior" target_ops method. */
void
aarch64_linux_nat_target::post_startup_inferior (ptid_t ptid)
{
low_forget_process (ptid.pid ());
aarch64_linux_get_debug_reg_capacity (ptid.pid ());
linux_nat_target::post_startup_inferior (ptid);
}
/* Implement the "post_attach" target_ops method. */
void
aarch64_linux_nat_target::post_attach (int pid)
{
low_forget_process (pid);
/* Set the hardware debug register capacity. If
aarch64_linux_get_debug_reg_capacity is not called
(as it is in aarch64_linux_child_post_startup_inferior) then
software watchpoints will be used instead of hardware
watchpoints when attaching to a target. */
aarch64_linux_get_debug_reg_capacity (pid);
linux_nat_target::post_attach (pid);
}
/* Implement the "read_description" target_ops method. */
const struct target_desc *
aarch64_linux_nat_target::read_description ()
{
int ret, tid;
gdb_byte regbuf[ARM_VFP3_REGS_SIZE];
struct iovec iovec;
tid = inferior_ptid.lwp ();
iovec.iov_base = regbuf;
iovec.iov_len = ARM_VFP3_REGS_SIZE;
ret = ptrace (PTRACE_GETREGSET, tid, NT_ARM_VFP, &iovec);
if (ret == 0)
return aarch32_read_description ();
CORE_ADDR hwcap = linux_get_hwcap (this);
return aarch64_read_description (aarch64_sve_get_vq (tid),
hwcap & AARCH64_HWCAP_PACA);
}
/* Convert a native/host siginfo object, into/from the siginfo in the
layout of the inferiors' architecture. Returns true if any
conversion was done; false otherwise. If DIRECTION is 1, then copy
from INF to NATIVE. If DIRECTION is 0, copy from NATIVE to
INF. */
bool
aarch64_linux_nat_target::low_siginfo_fixup (siginfo_t *native, gdb_byte *inf,
int direction)
{
struct gdbarch *gdbarch = get_frame_arch (get_current_frame ());
/* Is the inferior 32-bit? If so, then do fixup the siginfo
object. */
if (gdbarch_bfd_arch_info (gdbarch)->bits_per_word == 32)
{
if (direction == 0)
aarch64_compat_siginfo_from_siginfo ((struct compat_siginfo *) inf,
native);
else
aarch64_siginfo_from_compat_siginfo (native,
(struct compat_siginfo *) inf);
return true;
}
return false;
}
/* Returns the number of hardware watchpoints of type TYPE that we can
set. Value is positive if we can set CNT watchpoints, zero if
setting watchpoints of type TYPE is not supported, and negative if
CNT is more than the maximum number of watchpoints of type TYPE
that we can support. TYPE is one of bp_hardware_watchpoint,
bp_read_watchpoint, bp_write_watchpoint, or bp_hardware_breakpoint.
CNT is the number of such watchpoints used so far (including this
one). OTHERTYPE is non-zero if other types of watchpoints are
currently enabled. */
int
aarch64_linux_nat_target::can_use_hw_breakpoint (enum bptype type,
int cnt, int othertype)
{
if (type == bp_hardware_watchpoint || type == bp_read_watchpoint
|| type == bp_access_watchpoint || type == bp_watchpoint)
{
if (aarch64_num_wp_regs == 0)
return 0;
}
else if (type == bp_hardware_breakpoint)
{
if (aarch64_num_bp_regs == 0)
return 0;
}
else
gdb_assert_not_reached ("unexpected breakpoint type");
/* We always return 1 here because we don't have enough information
about possible overlap of addresses that they want to watch. As an
extreme example, consider the case where all the watchpoints watch
the same address and the same region length: then we can handle a
virtually unlimited number of watchpoints, due to debug register
sharing implemented via reference counts. */
return 1;
}
/* Insert a hardware-assisted breakpoint at BP_TGT->reqstd_address.
Return 0 on success, -1 on failure. */
int
aarch64_linux_nat_target::insert_hw_breakpoint (struct gdbarch *gdbarch,
struct bp_target_info *bp_tgt)
{
int ret;
CORE_ADDR addr = bp_tgt->placed_address = bp_tgt->reqstd_address;
int len;
const enum target_hw_bp_type type = hw_execute;
struct aarch64_debug_reg_state *state
= aarch64_get_debug_reg_state (inferior_ptid.pid ());
gdbarch_breakpoint_from_pc (gdbarch, &addr, &len);
if (show_debug_regs)
fprintf_unfiltered
(gdb_stdlog,
"insert_hw_breakpoint on entry (addr=0x%08lx, len=%d))\n",
(unsigned long) addr, len);
ret = aarch64_handle_breakpoint (type, addr, len, 1 /* is_insert */, state);
if (show_debug_regs)
{
aarch64_show_debug_reg_state (state,
"insert_hw_breakpoint", addr, len, type);
}
return ret;
}
/* Remove a hardware-assisted breakpoint at BP_TGT->placed_address.
Return 0 on success, -1 on failure. */
int
aarch64_linux_nat_target::remove_hw_breakpoint (struct gdbarch *gdbarch,
struct bp_target_info *bp_tgt)
{
int ret;
CORE_ADDR addr = bp_tgt->placed_address;
int len = 4;
const enum target_hw_bp_type type = hw_execute;
struct aarch64_debug_reg_state *state
= aarch64_get_debug_reg_state (inferior_ptid.pid ());
gdbarch_breakpoint_from_pc (gdbarch, &addr, &len);
if (show_debug_regs)
fprintf_unfiltered
(gdb_stdlog, "remove_hw_breakpoint on entry (addr=0x%08lx, len=%d))\n",
(unsigned long) addr, len);
ret = aarch64_handle_breakpoint (type, addr, len, 0 /* is_insert */, state);
if (show_debug_regs)
{
aarch64_show_debug_reg_state (state,
"remove_hw_watchpoint", addr, len, type);
}
return ret;
}
/* Implement the "insert_watchpoint" target_ops method.
Insert a watchpoint to watch a memory region which starts at
address ADDR and whose length is LEN bytes. Watch memory accesses
of the type TYPE. Return 0 on success, -1 on failure. */
int
aarch64_linux_nat_target::insert_watchpoint (CORE_ADDR addr, int len,
enum target_hw_bp_type type,
struct expression *cond)
{
int ret;
struct aarch64_debug_reg_state *state
= aarch64_get_debug_reg_state (inferior_ptid.pid ());
if (show_debug_regs)
fprintf_unfiltered (gdb_stdlog,
"insert_watchpoint on entry (addr=0x%08lx, len=%d)\n",
(unsigned long) addr, len);
gdb_assert (type != hw_execute);
ret = aarch64_handle_watchpoint (type, addr, len, 1 /* is_insert */, state);
if (show_debug_regs)
{
aarch64_show_debug_reg_state (state,
"insert_watchpoint", addr, len, type);
}
return ret;
}
/* Implement the "remove_watchpoint" target_ops method.
Remove a watchpoint that watched the memory region which starts at
address ADDR, whose length is LEN bytes, and for accesses of the
type TYPE. Return 0 on success, -1 on failure. */
int
aarch64_linux_nat_target::remove_watchpoint (CORE_ADDR addr, int len,
enum target_hw_bp_type type,
struct expression *cond)
{
int ret;
struct aarch64_debug_reg_state *state
= aarch64_get_debug_reg_state (inferior_ptid.pid ());
if (show_debug_regs)
fprintf_unfiltered (gdb_stdlog,
"remove_watchpoint on entry (addr=0x%08lx, len=%d)\n",
(unsigned long) addr, len);
gdb_assert (type != hw_execute);
ret = aarch64_handle_watchpoint (type, addr, len, 0 /* is_insert */, state);
if (show_debug_regs)
{
aarch64_show_debug_reg_state (state,
"remove_watchpoint", addr, len, type);
}
return ret;
}
/* Implement the "region_ok_for_hw_watchpoint" target_ops method. */
int
aarch64_linux_nat_target::region_ok_for_hw_watchpoint (CORE_ADDR addr, int len)
{
return aarch64_linux_region_ok_for_watchpoint (addr, len);
}
/* Implement the "stopped_data_address" target_ops method. */
bool
aarch64_linux_nat_target::stopped_data_address (CORE_ADDR *addr_p)
{
siginfo_t siginfo;
int i;
struct aarch64_debug_reg_state *state;
if (!linux_nat_get_siginfo (inferior_ptid, &siginfo))
return false;
/* This must be a hardware breakpoint. */
if (siginfo.si_signo != SIGTRAP
|| (siginfo.si_code & 0xffff) != TRAP_HWBKPT)
return false;
/* Check if the address matches any watched address. */
state = aarch64_get_debug_reg_state (inferior_ptid.pid ());
for (i = aarch64_num_wp_regs - 1; i >= 0; --i)
{
const unsigned int offset
= aarch64_watchpoint_offset (state->dr_ctrl_wp[i]);
const unsigned int len = aarch64_watchpoint_length (state->dr_ctrl_wp[i]);
const CORE_ADDR addr_trap = (CORE_ADDR) siginfo.si_addr;
const CORE_ADDR addr_watch = state->dr_addr_wp[i] + offset;
const CORE_ADDR addr_watch_aligned = align_down (state->dr_addr_wp[i], 8);
const CORE_ADDR addr_orig = state->dr_addr_orig_wp[i];
if (state->dr_ref_count_wp[i]
&& DR_CONTROL_ENABLED (state->dr_ctrl_wp[i])
&& addr_trap >= addr_watch_aligned
&& addr_trap < addr_watch + len)
{
/* ADDR_TRAP reports the first address of the memory range
accessed by the CPU, regardless of what was the memory
range watched. Thus, a large CPU access that straddles
the ADDR_WATCH..ADDR_WATCH+LEN range may result in an
ADDR_TRAP that is lower than the
ADDR_WATCH..ADDR_WATCH+LEN range. E.g.:
addr: | 4 | 5 | 6 | 7 | 8 |
|---- range watched ----|
|----------- range accessed ------------|
In this case, ADDR_TRAP will be 4.
To match a watchpoint known to GDB core, we must never
report *ADDR_P outside of any ADDR_WATCH..ADDR_WATCH+LEN
range. ADDR_WATCH <= ADDR_TRAP < ADDR_ORIG is a false
positive on kernels older than 4.10. See PR
external/20207. */
*addr_p = addr_orig;
return true;
}
}
return false;
}
/* Implement the "stopped_by_watchpoint" target_ops method. */
bool
aarch64_linux_nat_target::stopped_by_watchpoint ()
{
CORE_ADDR addr;
return stopped_data_address (&addr);
}
/* Implement the "watchpoint_addr_within_range" target_ops method. */
bool
aarch64_linux_nat_target::watchpoint_addr_within_range (CORE_ADDR addr,
CORE_ADDR start, int length)
{
return start <= addr && start + length - 1 >= addr;
}
/* Implement the "can_do_single_step" target_ops method. */
int
aarch64_linux_nat_target::can_do_single_step ()
{
return 1;
}
/* Implement the "thread_architecture" target_ops method. */
struct gdbarch *
aarch64_linux_nat_target::thread_architecture (ptid_t ptid)
{
/* Return the gdbarch for the current thread. If the vector length has
changed since the last time this was called, then do a further lookup. */
uint64_t vq = aarch64_sve_get_vq (ptid.lwp ());
/* Find the current gdbarch the same way as process_stratum_target. Only
return it if the current vector length matches the one in the tdep. */
inferior *inf = find_inferior_ptid (this, ptid);
gdb_assert (inf != NULL);
if (vq == gdbarch_tdep (inf->gdbarch)->vq)
return inf->gdbarch;
/* We reach here if the vector length for the thread is different from its
value at process start. Lookup gdbarch via info (potentially creating a
new one), stashing the vector length inside id. Use -1 for when SVE
unavailable, to distinguish from an unset value of 0. */
struct gdbarch_info info;
gdbarch_info_init (&info);
info.bfd_arch_info = bfd_lookup_arch (bfd_arch_aarch64, bfd_mach_aarch64);
info.id = (int *) (vq == 0 ? -1 : vq);
return gdbarch_find_by_info (info);
}
/* Define AArch64 maintenance commands. */
static void
add_show_debug_regs_command (void)
{
/* A maintenance command to enable printing the internal DRi mirror
variables. */
add_setshow_boolean_cmd ("show-debug-regs", class_maintenance,
&show_debug_regs, _("\
Set whether to show variables that mirror the AArch64 debug registers."), _("\
Show whether to show variables that mirror the AArch64 debug registers."), _("\
Use \"on\" to enable, \"off\" to disable.\n\
If enabled, the debug registers values are shown when GDB inserts\n\
or removes a hardware breakpoint or watchpoint, and when the inferior\n\
triggers a breakpoint or watchpoint."),
NULL,
NULL,
&maintenance_set_cmdlist,
&maintenance_show_cmdlist);
}
void
_initialize_aarch64_linux_nat (void)
{
add_show_debug_regs_command ();
/* Register the target. */
linux_target = &the_aarch64_linux_nat_target;
add_inf_child_target (&the_aarch64_linux_nat_target);
}
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