For manual startup, place memtest_shared.bin anywhere into your board RAM. Set registers as follows:

[AchyuthAGNA5675]

Hi sir,
For this above issue, can you please provide me the steps to load memtest_shared.bin into board RAM & also procedures to set registers and run memtest86 , i have a RISCV board from si-five. I need to observe and valuate individual CPU cores ie; Hart[0] to Hart [3], can you please help me? am a complete newbiee to this.

[atrosinenko]

Hi @AchyuthAGNA5675,

First of all, I would strongly suggest experimenting a lot on a full-system emulator such as QEMU before trying to run it on real hardware. I never tested my port on a RISC-V board, just on emulator and FPGA-based soft-processor, so I cannot say if it is safe enough taking into account, say, one-time-programmable fuses or maybe some hard-to-restore firmware of the real board.

Unfortunately, I wrote this readme long ago and I cannot remember all of the details. I guess memtest_shared was an ELF image that can be used by GDB for functions, debug info, etc. and each of memtest_shared.bin and memtest.uboot is probably a self-contained executable. Please note that U-Boot bootloader has its own format for bundling kernel, initrd and other blobs together, each with its own load address written to bundle's header. memtest_shared.bin, on the other hand, is simply raw memory contents (thus, loader has to be instructed where to load it via command line).

You can use something like fatload command of U-Boot shell (or similar command for your filesystem) to load a file into memory at a specified address. I cannot remember right now which command to use to actually transfer control to that binary - maybe it is named go or some of boot* commands, then $a0 and $a1 are "arguments" in order.

Please note that U-Boot has its own shell and this shell can execute shell scripts. The shell is not /bin/sh compatible, so it is worth reading the docs on its syntax and a lot of builtin commands are available to inspect that are quite frequently implemented as a script strings composed of simpler commands.

The nice thing with raw image (*.bin) is that GDB has a command to copy a file from host file system into target's memory and registers can be set just as set $a0 = 0x1234. In case of real hardware you can usually debug anything, even the bootloader, over JTAG (say, in my case I instantiated a JTAG on spare pins in the RocketChip design and after a bit of googling found a manual on using RaspberryPi running an OpenOCD as a JTAG adapter). In case of QEMU you should probably just enable gdbserver on QEMU command line and connect to it instead of OpenOCD.

[atrosinenko]

These days, I have written a series of articles on step-by-step porting a soft-processor to a cheap Zeowaa board bought on AliExpress and then adjusting bootloaders and Linux kernel for that soft-processor. This part covers specifically MemTest86+: https://habr.com/ru/post/484026/ - these are in Russian but hope Google Translate helps.