The original names are confusing; the symbols' addresses point to the start and end of the
sbi executable ram area. This may also reside in l2lim and not in ddr, depending on the
configuration, and this is defined in the linker script.
Signed-off-by: Jukka Laitinen <jukkax@ssrc.tii.ae>
Version 1.3.1 is the latest tagged version as of November
the 21st, 2023. This patch prepares the required changes
to make v1.3.1 work.
Signed-off-by: Eero Nurkkala <eero.nurkkala@offcode.fi>
SiFive document: "ECC Error Handling Guide" states:
"Any SRAM block or cache memory containing ECC functionality needs to be
initialized prior to use. ECC will correct defective bits based on memory
contents, so if memory is not first initialized to a known state, then ECC
will not operate as expected. It is recommended to use a DMA, if available,
to write the entire SRAM or cache to zeros prior to enabling ECC reporting.
If no DMA is present, use store instructions issued from the processor."
Clean the cache at this early stage so no ECC errors will be flooding later.
Signed-off-by: Eero Nurkkala <eero.nurkkala@offcode.fi>
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.
It is not really needed; g_hart_stacks is only used during SBI init as
a temporary stack area. We can use the scratch area buffers for this, as
the scratch areas define almost 4K of extra space, which is used for
exception stacks anyway.
There is no such section. Instead, place the object mpfs_head.o at the start of
the text.
Put mpfs_head.o directly into the arch library; there is no need to define
it separately in HEAD_ASRC.
Signed-off-by: Jukka Laitinen <jukkax@ssrc.tii.ae>
Add the rest of the OpenSBI code to .text.sbi -section. They belong
to there. This frees up some space in the very limited eNVM.
Signed-off-by: Eero Nurkkala <eero.nurkkala@offcode.fi>
OpenSBI may be compiled as an external library. OpenSBI commit d249d65
(Dec. 11, 2021) needs to be reverted as it causes memcpy / memcmp to
end up in the wrong section. That issue has yet no known workaround.
OpenSBI may be lauched from the hart0 (e51). It will start the U-Boot
and eventually the Linux kernel on harts 1-4.
OpenSBI, once initialized properly, will trap and handle illegal
instructions (for example, CSR time) and unaligned address accesses
among other things.
Due to size size limitations for the mpfs eNVM area where the NuttX
is located, we actually set up the OpenSBI on its own section which
is in the bottom of the DDR memory. Special care must be taken so that
the kernel doesn't override the OpenSBI. For example, the Linux device
tree may reserve some space from the beginning:
opensbi_reserved: opensbi@80000000 {
reg = <0x80000000 0x200000>;
label = "opensbi-reserved";
};
The resulting nuttx.bin file is very large, but objcopy is used to
create the final binary images for the regions (eNVM and DDR) using
the nuttx elf file.
Co-authored-by: Petro Karashchenko <petro.karashchenko@gmail.com>
Signed-off-by: Eero Nurkkala <eero.nurkkala@offcode.fi>
