reason:
1 On different architectures, we can utilize more optimized strategies
to implement up_current_regs/up_set_current_regs.
eg. use interrupt registersor percpu registers.
code size
before
text data bss dec hex filename
262848 49985 63893 376726 5bf96 nuttx
after
text data bss dec hex filename
262844 49985 63893 376722 5bf92 nuttx
size change -4
Configuring NuttX and compile:
$ ./tools/configure.sh -l qemu-armv8a:nsh_smp
$ make
Running with qemu
$ qemu-system-aarch64 -cpu cortex-a53 -smp 4 -nographic \
-machine virt,virtualization=on,gic-version=3 \
-net none -chardev stdio,id=con,mux=on -serial chardev:con \
-mon chardev=con,mode=readline -kernel ./nuttx
Signed-off-by: hujun5 <hujun5@xiaomi.com>
There is a tiny possibility that when a process is started a trap is
taken which causes a context switch. This moves the kernel stack
unexpectedly and the task start logic no longer works.
Fix this by recording the initial context location, and use that to
trampoline into the user process with interrupts disabled. This ensures
the context stays intact AND the kernel stack is fully unwound before
the user process starts.
This is the initial version for kernel mode build on the arm64 platform.
It works much in the same way as the risc-v implementation so any
highlights can be read from there.
Features that have been tested working:
- Creating address environments
- Loading init (nsh) from elf file
- Booting to nsh
- Starting other processes from nsh
- ostest runs to completion
Features that are not tested / do not work:
- SHM / shared memory support
- Kernel memory mapping (MM_KMAP)
- fork/vfork
An example qemu target is provided as a separate patch:
tools/configure.sh qemu-armv8a:knsh
reduce the time consumed by function call
test:
We can use qemu for testing.
compiling
make distclean -j20; ./tools/configure.sh -l qemu-armv8a:nsh_smp ;make -j20
running
qemu-system-aarch64 -cpu cortex-a53 -smp 4 -nographic -machine virt,virtualization=on,gic-version=3 -net none -chardev stdio,id=con,mux=on -serial chardev:con -mon chardev=con,mode=readline -kernel ./nuttx
Signed-off-by: hujun5 <hujun5@xiaomi.com>
Current `CONFIG_PAGING` refers to an experimental implementation
to enable embedded MCUs with some limited RAM space to execute
large programs from some non-random access media.
On-demand paging should be implemented for the kernel mode with
address environment implementation enabled.
To compile arm64 NuttX, use the following command:
./tools/configure.sh -l qemu-armv8a:nsh_fiq
To run，use the following command
qemu-system-aarch64 -cpu cortex-a53 -nographic -machine virt,virtualization=on,gic-version=3 -net none -chardev stdio,id=con,mux=on -serial chardev:con -mon chardev=con,mode=readline -kernel ./nuttx
Signed-off-by: hujun5 <hujun5@xiaomi.com>
N/A
Summary:
Arm64 support for NuttX, Features supported:
1. Cortex-a53 single core and SMP support: it's can run into nsh shell at
qemu virt machine.
2. qemu-a53 board configuration support: it's only for evaluate propose
3. FPU support for armv8-a: FPU context switching at NEON/floating-point
TRAP is supported.
4. psci interface, armv8 cache operation(data cache) and smccc support.
5. fix mass code style issue, thank for @xiaoxiang781216, @hartmannathan @pkarashchenko
Please refer to boards/arm64/qemu/qemu-a53/README.txt for detail
Note:
1. GCC MACOS issue
The GCC 11.2 toolchain for MACOS may get crash while compiling
float operation function, the following link describe the issue
and give analyse at the issue:
https://bugs.linaro.org/show_bug.cgi?id=5825
it's seem GCC give a wrong instruction at certain machine which
without architecture features
the new toolchain is not available still, so just disable the MACOS
cibuild check at present
Signed-off-by: qinwei1 <qinwei1@xiaomi.com>
