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.
The cyw43-driver is a submodule in the pick-sdk, if the submodule is
not updated, the dummy firmware driver will be used, update the document
to correct the setup flow.
${PICO_SDK_PATH}/lib/cyw43-driver/firmware/43439A0-7.95.49.00.combined
Signed-off-by: chao an <anchao@xiaomi.com>
Summary:
- Since QEMU does not report L2CC information correctly,
NuttX stops if DEBUG_ASSERTIONS=y.
- This commit adds DEBUG_ASSERTIONS=y to citest/defconfigs
and disables L2CC related configs.
- Also, it disables RAMLOG to show the crash information
Impact:
- None
Testing:
- Tested with QEMU-7.1
Signed-off-by: Masayuki Ishikawa <Masayuki.Ishikawa@jp.sony.com>
continue the follow work:
commit 43e7b13697
Author: Xiang Xiao <xiaoxiang@xiaomi.com>
Date: Sun Jan 22 19:31:32 2023 +0800
assert: Log the assertion expression in case of fail
Signed-off-by: Xiang Xiao <xiaoxiang@xiaomi.com>
Summary:
- This commit adjusts TCP and UDP configurations based on
sabre-6quad/configs/netnsh/defconfig
Impact:
- sabre-6quad only
Testing:
- Tested with QEMU-7.1
Signed-off-by: Masayuki Ishikawa <Masayuki.Ishikawa@jp.sony.com>
since mmap may exist in block_operations, but truncate may not,
moving mmap beforee truncate could make three struct more compatible
Signed-off-by: Xiang Xiao <xiaoxiang@xiaomi.com>
- Add mmap into file_operations and remove it from ioctl definitions.
- Add mm_map structure definitions to support future unmapping
- Modify all drivers to initialize the operations struct accordingly
Signed-off-by: Jukka Laitinen <jukkax@ssrc.tii.ae>
- Add truncate into file_operations
- Move truncate to be common for mountpt_operations and file_operations
- Modify all drivers to initialize the operations struct accordingly
Signed-off-by: Jukka Laitinen <jukkax@ssrc.tii.ae>
- Adds support for the Starcat Jupiter Nano
SAMA5D27C-LD1G board
- https://github.com/starcat-io/jupiter-nano
- this board is very similar to the Microchip/Atmel
SAMA5D2-Xplained board (sama5d2-xult)
I don't know how to handle this properly as I don't know what this
symbol table is supposed to do. Most likely the part that uses the
symbol table needs to be patched also...
- in NuttX 11.x and 12.x the nuttx entry point
for the sama5d2-xult board changed to 0x20008E20
(from 0x2008040).
This change updates defconfigs and the README.txt
to reflect that.
- no code changes
