Messages in this thread | | | Date | Thu, 30 Jun 2022 21:07:17 +0100 | From | Sudeep Holla <> | Subject | Re: [PATCH v5 09/19] arch_topology: Use the last level cache information from the cacheinfo |
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On Thu, Jun 30, 2022 at 07:20:04PM +0000, Conor.Dooley@microchip.com wrote: > > > On 30/06/2022 18:35, Sudeep Holla wrote: > > On Thu, Jun 30, 2022 at 04:37:50PM +0000, Conor.Dooley@microchip.com wrote: > >> On 30/06/2022 11:39, Sudeep Holla wrote: > >>> > >>> I can't think of any reason for that to happen unless detect_cache_attributes > >>> is failing from init_cpu_topology and we are ignoring that. > >>> > >>> Are all RISC-V platforms failing on -next or is it just this platform ? > >> > >> I don't know. I only have SoCs with this core complex & one that does not > >> work with upstream. I can try my other board with this SoC - but I am on > >> leave at the moment w/ a computer or internet during the day so it may be > >> a few days before I can try it. > >> > > > > Sure, no worries. > > > >> However, Niklas Cassel has tried to use the Canaan K210 on next-20220630 > >> but had issues with RCU stalling: > >> https://lore.kernel.org/linux-riscv/Yr3PKR0Uj1bE5Y6O@x1-carbon/T/#m52016996fcf5fa0501066d73352ed8e806803e06 > >> Not going to claim any relation, but that's minus 1 to the platforms that > >> can be used to test this on upstream RISC-V. > >> > > > > Ah OK, will check and ask full logs to see if there is any relation. > > > >>> We may have to try with some logs in detect_cache_attributes, > >>> last_level_cache_is_valid and last_level_cache_is_shared to check where it > >>> is going wrong. > >>> > >>> It must be crashing in smp_callin->update_siblings_masks->last_level_cache_is_shared > > > So, looks like there's a problem in cache_leaves_are_shared() which is hit > by the above path. Both of the if clauses are false, and the function falls > through to return sib_leaf->fw_token == this_leaf->fw_token;
Both if() failing is expected and that statement return sib_leaf->fw_token == this_leaf->fw_token; execution is correct.
> Both sib_leaf & this_leaf seem to be null. >
But this is wrong as last_level_cache_is_shared checks for last_level_cache_is_valid which must return false if the fw_token = NULL So we must not hit the above return statement with NULL fw_token.
> static inline bool cache_leaves_are_shared(struct cacheinfo *this_leaf, > struct cacheinfo *sib_leaf) > { > /* > * For non DT/ACPI systems, assume unique level 1 caches, > * system-wide shared caches for all other levels. This will be used > * only if arch specific code has not populated shared_cpu_map > */ > if (!(IS_ENABLED(CONFIG_OF) || IS_ENABLED(CONFIG_ACPI))) > return !(this_leaf->level == 1); > > if ((sib_leaf->attributes & CACHE_ID) && > (this_leaf->attributes & CACHE_ID)) > return sib_leaf->id == this_leaf->id; > > return sib_leaf->fw_token == this_leaf->fw_token; > } > > Any ideas what to look at next?
I wonder how did we not get last_level_cache_is_valid as false if the fw_node is NULL. But it should not be NULL at the first place.
-- Regards, Sudeep
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