Linux kernel uses M-mode trap for handling Inter-Hart Communication (IHC).
This patch provides all the required functionalities for this purpose.
Previously, HSS bootloader was required. Now, NuttX is run as the
bootloader providing OpenSBI vendor extensions instead. This setup has
been tested on the following configuration:
- Hart 0 has NuttX in bootloader mode with OpenSBI
- Hart 1 unused
- Hart 2 has NuttX configured at 0xa2000000
- Hart 3 has U-boot / Linux kernel (at 0x80200000)
- Hart 4 has U-boot / Linux kernel (at 0x80200000)
Upon startup, NuttX on hart 0 will initialize SD-card driver, loads
the hart 2 NuttX from the SD-card and loads the U-boot to 0x80200000.
Also the nuttx.sbi -binary is loaded from SD-card into address 0x80000000,
which is also marked as reserved area in the Linux kernel device tree (for
the chuck 0x80000000 - 0x80200000).
Hart 2 NuttX waits until Linux kernel (IHC master) is started. After the
initial handshake, RPMsg / virtIO bus along with the IHC may be used for
proper AMP mode.
Signed-off-by: Eero Nurkkala <eero.nurkkala@offcode.fi>
Summary:
- I noticed that rv-virt:knsh64 crashes when it executes the init.
- This commit fixes this issue.
Impact:
- None
Testing:
- Tested with rv-virt:knsh64
Signed-off-by: Masayuki Ishikawa <Masayuki.Ishikawa@jp.sony.com>
The FPU register saving upon vfork entry was missing.
Also added macro that tells the actual size of an FPU reg, instead
of just having a coefficient for qfpu/no-qfpu.
- Remove most of the ifeq-conditions and replace them with variables.
- Move the -I flag for 3rd party headers to opensbi/Make.defs
This clean-up / generalization makes it much simpler to add a new SBI
implementation, without the need to add a bunch of ifeq / elif conditions
to the makefile.
Let the user pick what runs on the harts. For example, the
default configuration now supports NuttX on hart2 and Linux
kernel on harts 3 and 4. Also fix a few issues in the code.
Signed-off-by: Eero Nurkkala <eero.nurkkala@offcode.fi>
g_mpfs_ack_sig and g_mpfs_rx_sig are better used with
SEM_INITIALIZER(0) (signalling) rather than with
SEM_INITIALIZER(1) (mutual exclusion).
Co-authored-by: Petro Karashchenko <petro.karashchenko@gmail.com>
Signed-off-by: Eero Nurkkala <eero.nurkkala@offcode.fi>
PR#6249 was already merged without the review fixes. Provide the
fixes here on a separate patch.
Co-authored-by: Petro Karashchenko <petro.karashchenko@gmail.com>
Signed-off-by: Eero Nurkkala <eero.nurkkala@offcode.fi>
Summary:
- This commit adds MMU support for qemu-rv
- Please note that mtimer is disabled for S-mode because
the mtimer needs to be accessed in M-mode
Impact:
- qemu-rv only
Testing:
- Tested with rv-virt:knsh64 (will be pushed later)
Signed-off-by: Masayuki Ishikawa <Masayuki.Ishikawa@jp.sony.com>
This provides an example of Asymmetric Multiprocessing (AMP). The
master from Linux sends pings that this NuttX echoes back. The system
uses RPMsg from OpenAMP.
The Inter-Hart Communication module is present in the vendor's software
stack with the tag "2021.11". The software is present on github at the
polarfire-soc project. The following conditions must be met:
1. FPGA programmed with 2021.11 software
2. HSS (Vendor bootloader) with 2021.11 software
3. U-boot and Linux kernel from 2011.11 software
Currently the IHC works as a slave only on the hart number 4.
On the NuttX side, this patch uses rptun that incorporates rpmsg and
virtio. If it used only rpmsg and virtio, the future maintenance would
likely be much heavier. Using rptun also simplifies many things.
Upon success, the master side from Linux may issue an example test:
root@icicle-kit-es-amp:/opt/microchip/amp/rpmsg-pingpong# ./rpmsg-pingpong
However, the rpmsg-pingpong.c (compiled on target with gcc), may need to
be modified as seen below to match the device id:
- char *rpmsg_dev="virtio0.rpmsg-amp-demo-channel.-1.0";
+ char *rpmsg_dev="virtio0.rpmsg-amp-demo-channel.-1.1024";
This work uses a separate linker script. Due to a bug yet unknown to date,
a small NuttX, when loaded by the vendor HSS bootloader, will cause the
Linux kernel to hang at boot. Thus, the binary size is increased with
a section 'filler_area' whose only purpose is to increase the image size
so that the Linux kernel will boot up.
Signed-off-by: Eero Nurkkala <eero.nurkkala@offcode.fi>
Implement a generic access rights modification procedure instead
of the procedures that only do one thing (enable/disable write)
to one section (text).
Summary:
- Because a context switch issue still exists with FPU,
it should be enabled only if EXPERIMENTAL=y
Impact:
- None
Testing:
- Tested with ostest
Signed-off-by: Masayuki Ishikawa <Masayuki.Ishikawa@jp.sony.com>
When the .elf file is loaded from disk, the kernel must be given write
access to the allocated .text section in the task's address environment.
The access is removed after the elf is loaded and relocations are done.
NOTE:
The reason this works for the ARM implementation, is that the ARM MMU
can be configured to give write access for the privileged mode, but
revoke write access for the user mode.
Regardless, it would be smart to revoke write access even for the
kernel, when the kernel does not need it. This framework allows doing
that, if someone wishes to take up the task.
Summary:
- This commit adds support for semihosting and hostfs
Impact:
- None
Testing:
- Tested with nsh and nsh64 (defconfig will be updated later)
Signed-off-by: Masayuki Ishikawa <Masayuki.Ishikawa@jp.sony.com>
Mappings are done with vaddr=paddr.
- I/O space mapped with two gigapages
- Kernel space mapped to statically allocated page tables. 2MB of kernel
memory is supported.
- Page pool is mapped to the kernel space, to allow virtual memory access
for the kernel e.g. to initialize the page memory when it is allocated.
by renaming riscv_dispatch_syscall to sys_callx, so the caller
don't need the immediate step(syscallx->riscv_dispatch_syscall)
Signed-off-by: Xiang Xiao <xiaoxiang@xiaomi.com>
Using the Kconfig macro does not work for RISC-V target, as there the
user heap follows .data/.bss and does not obey any Kconfig provided
boundary.
Added stubs for ARM and Z80 also.
