| 19 Feb 2024 |
 Pratham Patel (you can mention me) | Might add the Milk-V Oasis to that list once it's launched, since it uses SiFive's cores (which I trust to have no major issues), but only after testing things out :) | 10:56:12 |
 Steven Keuchel | Do you have any specific silicon erratas you are referring to? I'm only interested in those that impact user-mode functionality, rather than being solely kernel-mode concerns. I know about the linux ERRATA_THEAD_QSPINLOCK, but I would like to know about others, if they exist. The information is a bit hard to find. | 11:35:18 |
| Pratham Patel (you can mention me) | All the RISC-V related erratas that I know: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/arch/riscv/include/asm/errata_list.h | 11:38:14 |
| Steven Keuchel | ahh ok. as far as i understand it, the current erratas in upstream linux do not affect user-mode. | 11:44:43 |
| Steven Keuchel | but correct me if i'm wrong, I would really like to know ;) | 11:44:55 |
| Pratham Patel (you can mention me) | that's for the core though, pretty sure both kernel-space and user-space are affected | 11:45:17 |
| Pratham Patel (you can mention me) | also, these erratas are errors in implementing the RISC-V spec in the actual Linux-capable core, individual or on SoC | 11:50:05 |
| Pratham Patel (you can mention me) | That said, I do wish to buy that Lichee 4A cluster board with 7 slots so I can parallel build to check for build failures since we're still bootstrapping. Once a build succeeds, I'd build it on the VF2 that I own. | 11:54:03 |
| Steven Keuchel | In reply to @thefossguy:matrix.org
also, these erratas are errors in implementing the RISC-V spec in the actual Linux-capable core, individual or on SoC Yes, the behaviour may differ from the official spec, but you still have to consider the impact.
- ERRATA_THEAD_PBMT is about page tables, it's kernel-mode specific
- ERRATA_THEAD_PMU is about performance counter overflows
- ERRATA_THEAD_CMO I don't understand enough, but you can also disable those extensions
- ERRATA_THEAD_QSPINLOCK is a case where the vendor implementation is more restricted than what the spec requires
So the question is if these warrant not trusting the machines as build boxes. For me, these erratas are not major issues.
| 12:15:49 |
| Steven Keuchel | That being said, I would trust none of these as production machines for a database or something. | 12:16:06 |
| Steven Keuchel | For the pioneer: the sg2042-dev vendor kernel is not stable, and the PCIe support is a bit wonky which I would consider as a bigger issue at this point. But hopefully those can be resolved. | 12:17:20 |
