Hi Boris, On 29/08/18 08:38, Borislav Petkov wrote: > On Tue, Aug 28, 2018 at 06:09:24PM +0100, James Morse wrote: >> Does x86 have another source of memory-topology information it needs to >> correlate smbios with? > > Bah, pinpointing the DIMM on x86 is a mess. There's no reliable way to > say which DIMM it is in certain cases (interleaving, mirrorring, ...) > and it is all platform-dependent. So we do the layers to dump a memory > location (node, memory controller, ....) so that we can at least limit > the number of DIMMs the user needs to replace/try.
Right. I'd like ghes-edac to work in the same way for both architectures. I think this is best done by stuffing the dmi-handle in struct dimm_info during ghes_edac_dmidecode(), then populating the struct edac_raw_error_desc layers from the matching mci->dimms 'location'. For EDAC_MC_LAYER_ALL_MEM this boils down to a flat index, so pointer arithmetic on mci->dimms is an appropriate short cut. (We should probably 'FIXME: It shouldn't be hard to also fill the DIMM labels' at the same time so that no-one is tempted to interpret the edac:dimm-idx) > In an ideal world, I'd like to be able to query the SPD chips on the (oh, that can be done?) > DIMMs and build the topology and then when an error happens to say, > "error in DIMM <silkscreen>" where silkscreen is what is written on the > motherboard under the DIMM socket. > > But I don't see that happening any time soon... >> For arm there is nothing else describing the memory-topology, so as long as >> we >> can correlate the smbios table and ghes:cper records through the handles, we >> can >> get this working for all systems. > > And then make sure vendors fill in the proper info in smbios. Because that's > also a mess on x86. I got educated by the people who look after specifications last time I touched this [0]. SMBIOS tables are required by Arm's 'Server Base Boot Requirements', It lists the memory-device and physical-memory-array as required. I will drop them a note that we will be depending on the handle, and it should go on the list too... if its not populated on today's systems we can fall back to !e->enable_per_layer_report as we do today. Thanks, James [0] https://www.spinics.net/lists/arm-kernel/msg653133.html
