(1) Keep the `.init_array` and `.ctors` symbols and sort them according to their initialization priority.
(2) Exclude symbols ending with crtend.* and crtbegin.* to support c++
application.if we not exclude crtend.* crtbegin.* frame_dummy will be
added when enable any c++ application with global variables, this symbol
execution is problematic, removing it does not affect the application.
Signed-off-by: cuiziwei <cuiziwei@xiaomi.com>
Usually the startup script is placed under /etc. The contents of the etc directory
are compiled and linked with Nuttx binary in the form of romfs. After startup,
it will be mounted by Nsh.
etc is generated by the different boards, that use genromfs and xxd tools to generate
and compile it into the Nuttx, for example: boards/arm/at32/at32f437-mini/tool/mkromfs.sh
The more common method is etc image generated from the content in the corresponding
board/arch/board/board/src/etc directory, and added by Makefile for example:
boards/sim/sim/sim/src/etc.
But in kernel/protected mode, Nuttx kernel and apps are run in different privileged/
non-privileged mode or the isolated binarys, so as that nsh should use syscall to
access Nuttx kernel by exported API. In this scenario, nsh can not mount the etc image
content, because that is generated in board and as a part of Nuttx kernel.
changes:
- move etc romfs mount from nsh to Nuttx, but keep the script to parse and execute.
- move and rename the related CONFIG, move customized nsh_romfsimg.h to etc_romfs.c
in boards, and no need declaration for romfs_img/romfs_img_len.
This commit changes and updates all configurations in Nuttx arch/board as much as possible,
but if any missing, please refer to the following simple guide:
- rename CONFIG_NSH_ROMFSETC to CONFIG_ETC_ROMFS, and delete CONFIG_NSH_ARCHROMFS in defconfig
- rename the etc romfs mount configs, for example CONFIG_NSH_FATDEVNO to CONFIG_ETC_FATDEVNO
- move customized nsh_romfsimg.h to etc_romfs.c in board/arch/board/board/src and no need
declaration for romfs_img/romfs_img_len.
- delete default nsh_romfsimg.h, if ROMFSETC is enabled, should generate and compile etc_romfs.c
in board/arch/board/board/src.
Signed-off-by: fangxinyong <fangxinyong@xiaomi.com>
- migrated /README are removed from /boards
- there are a lot of READMEs that should be further converted to rst.
At the moment they are moved to Documentation/platforms and included in rst files
When I try to set priorities in certain programs, such as init_priority(HIGH_PRIORITY), I've noticed that during linking, there's no guarantee that the programs will be compiled in the sequence I've specified based on priority. This has led to some runtime errors in my program.
I realized that in the ld file, when initializing dynamic arrays, there's no assurance of initializing init_array.* before init_array. This has resulted in runtime errors in the program. Consequently, I've rearranged the init_array.* in the ld file of NuttX to be placed before init_array and added a SORT operation to init_array.* to ensure accurate initialization based on priorities during linking.
replace *(.init_array .init_array.*) with KEEP(*(.init_array .init_array.*)).
The KEEP statement within a linker script will instruct the linker to keep the specified section, even if no symbols inside it are referenced. This statement is used within the SECTIONS section of the linker script. This becomes relevant when garbage collection is performed at link time, enabled by passing the --gc-sections switch to the linker. The KEEP statement instructs the linker to use the specified section as a root node when creating a dependency graph, looking for unused sections. Essentially forcing the section to be marked as used.
Signed-off-by: cuiziwei <cuiziwei@xiaomi.com>
There is currently a big problem in the address environment handling which
is that the address environment is released too soon when the process is
exiting. The current MMU mappings will always be the exiting process's, which means
the system needs them AT LEAST until the next context switch happens. If
the next thread is a kernel thread, the address environment is needed for
longer.
Kernel threads "lend" the address environment of the previous user process.
This is beneficial in two ways:
- The kernel processes do not need an allocated address environment
- When a context switch happens from user -> kernel or kernel -> kernel,
the TLB does not need to be flushed. This must be done only when
changing to a different user address environment.
Another issue is when a new process is created; the address environment
of the new process must be temporarily instantiated by up_addrenv_select().
However, the system scheduler does not know that the process has a different
address environment to its own and when / if a context restore happens, the
wrong MMU page directory is restored and the process will either crash or
do something horribly wrong.
The following changes are needed to fix the issues:
- Add mm_curr which is the current address environment of the process
- Add a reference counter to safeguard the address environment
- Whenever an address environment is mapped to MMU, its reference counter
is incremented
- Whenever and address environment is unmapped from MMU, its reference
counter is decremented, and tested. If no more references -> drop the
address environment and release the memory as well
- To limit the context switch delay, the address environment is freed in
a separate low priority clean-up thread (LPWORK)
- When a process temporarily instantiates another process's address
environment, the scheduler will now know of this and will restore the
correct mappings to MMU
Why is this not causing more noticeable issues ? The problem only happens
under the aforementioned special conditions, and if a context switch or
IRQ occurs during this time.
Follow: http://glennastory.net/boot/sysinit.html
This is first script that init runs is rc.sysinit. This
script does serval initialization tasks about basic service.
The boot sequence currently provided to the board level is:
board_earlyinitialize->
board_lateinitialize(Peripherals driver, core driver, ...)->
run rcS script(mount fs, run service) ->
board_appinitialize->
After this patch:
The boot sequence currently provided to the board level is:
board_earlyinitialize->
board_lateinitialize(core driver,...)->
run rc.sysinit script(mount fs, run core service) ->
board_appinitialize(Peripherals driver)->
run rcS script(run other service)->
So, Peripheral drivers can do more with the file system and
core services.
Signed-off-by: Jiuzhu Dong <dongjiuzhu1@xiaomi.com>
anjiahao