ACPICA commit 11522d6b894054fc4d62dd4f9863ec151296b386
The ACPI_DEBUGGER_EXEC is a problem now when the debugger code is compiled
but runtime disabled. They actually will get executed in this situation.
Although such executions are harmless if we can correctly make
acpi_db_single_step() a runtime stub, users may still do not want to see the
debugger print messages logged into OSPMs' kernel logs when a debugger
driver is not loaded to enable the debugger during runtime.
This patch fixes this issue by introducing new stub mechanism instead of
ACPI_DEBUGGER_EXEC. Lv Zheng.
Link: https://github.com/acpica/acpica/commit/11522d6b
Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
The following mechanisms are OSPM specific:
1. Redirect output destination to console: no file redirection will be
needed by an in-kernel debugger, there is even no file can be accessed
when the debugger is running in the kernel mode.
2. Output command prompts: programs other than acpiexec can have different
prompt characters and the prompt characters may be implemented as a
special character sequence to form a char device IO protocol.
3. Command ready/complete handshake: OSPM debugger may wait more conditions
to implement OSPM specific semantics (for example, FIFO full/empty
conditions for O_NONBLOCK or IO open/close conditions).
Leaving such OSPM specific stuffs in the ACPICA debugger core blocks
Linux debugger IO driver implementation.
Several new OSL APIs are provided by this patch:
1. acpi_os_initialize_command_signals: initialize command handshake mechanism
or any other OSPM specific stuffs.
2. acpi_os_terminate_command_signals: reversal of
acpi_os_initialize_command_signals.
3. acpi_os_wait_command_ready: putting debugger task into wait state when a
command is not ready. OSPMs can terminate command loop by returning
AE_CTRL_TERMINATE from this API. Normally, wait_event() or
wait_for_multiple_object() may be used to implement this API.
4. acpi_os_notify_command_complete: putting user task into running state when a
command has been completed. OSPMs can terminate command loop by
returning AE_CTRL_TERMINATE from this API. Normally, wake_up() or
set_event() may be used to implement this API.
This patch also converts current command signaling implementation into a
generic debugger layer (osgendbg.c) to be used by the existing OSPMs or
acpiexec, in return, Linux can have chance to implement its own command
handshake mechanism. This patch also implements acpiexec batch mode in a
multi-threading mode comaptible style as a demo (this can be confirmed by
configuring acpiexec into DEBUGGER_MULTI_THREADED mode where the batch mode
is still working). Lv Zheng.
Note that the OSPM specific command handshake mechanism is required by
Linux kernel because:
1. Linux kernel trends to use wait queue to synchronize two threads, using
mutexes to achieve that will cause false "dead lock" warnings.
2. The command handshake mechanism implemented by ACPICA is implemented in
this way because of a design issue in debugger IO streaming. Debugger IO
outputs are simply cached using a giant buffer, this should be tuned by
Linux in the future.
Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
When the debugger is running in the kernel mode, acpi_db_single_step() may
also be invoked by the kernel runtime code path but the single stepping
command prompt may be erronously logged as the kernel logs and runtime code
path cannot proceed.
This patch fixes this issue by adding acpi_gbl_db_thread_id for the debugger
thread and preventing acpi_db_single_step() to be invoked from other threads.
It is not suitable to add acpi_thread_id parameter for acpi_os_execute() as
the function may be implemented as work queue on some hosts. So it is
better to let the hosts invoke acpi_set_debugger_thread_id(). Currently
acpiexec is not configured as DEBUGGER_MULTI_THREADED, but we can do this.
When we do this, it is better to invoke acpi_set_debugger_thread_id() in
acpi_os_execute() when the execution type is OSL_DEBUGGER_MAIN_THREAD. The
support should look like:
create_thread(&tid);
if (type == OSL_DEBUGGER_MAIN_THREAD)
acpi_set_debugger_thread_id(tid);
resume_thread(tid);
Similarly, semop() may be used for pthread implementation. But this patch
simply skips debugger thread ID check for application instead of
introducing such complications as there is no need to skip
acpi_db_single_step() for an application debugger - acpiexec.
Note that the debugger thread ID can also be used by acpi_os_printf() to
filter out debugger output. Lv Zheng.
Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
ACPICA commit 0dd68e16274cd38224aa4781eddc57dc2cbaa108
The quit/exit commands shouldn't invoke acpi_terminate_debugger() and
acpi_terminate() right in the user command loop, because when the debugger
exits, the kernel ACPI subsystem shouldn't be terminated (acpi_terminate())
and the debugger should only be terminated by its users
(acpi_terminate_debugger()) rather than being terminated itself. Leaving such
invocations causes kernel panic when the debugger is shipped in the Linux
kernel.
This patch fixes this issue. Lv Zheng.
Link: https://github.com/acpica/acpica/commit/0dd68e16
Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
ACPICA commit bc2d3daa4bd429611451f28800def9fea55e63de
This patch exports debugger files to Linux.
Link: https://github.com/acpica/acpica/commit/bc2d3daa
Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
