On Thu, 2018-06-28 at 11:06 +0100, James Morse wrote: > Hi Mark, > > On 26/06/18 21:20, Mark Salter wrote: > > On Tue, 2018-06-26 at 15:51 +0100, James Morse wrote: > > > On 25/06/18 16:34, Mark Salter wrote: > > > > On Fri, 2018-06-22 at 11:19 -0400, Mark Salter wrote: > > > > > I'm going to hack something to get to the ghes info earlier in boot and > > > > > check the things you mention above wrt Error Status Block and GHES.0. > > > > > > > > So I had to end up instrumenting the EFI stub to see where the error came > > > > from. At the start of the stub, there is no GHES.2 error. The error first > > > > shows up after the stub's call to ExitBootServices returns. > > > > > > What's the notification type of GHES.2? I'm guessing POLLed or some kind of IRQ. > > > These systems don't have EL3, so the CPU must continue running while something > > > external generates the CPER records. The records being visible is the last point > > > the faulty-access could have been made, with the window of time depending on how > > > fast this external-thing receives and processes the error. > > > > There's a System Control Processor (slimpro) on the SoC which can interact with > > the CPU in various ways and which has access to memory and other hw. > > Thanks, saves me guessing! > > > > > > So it looks > > > > like the firmware itself is causing the error. There's still a chance that > > > > the stub is doing something wrong with the memory map passed to the > > > > firmware, so I'll try to eliminate that as well. > > > > > > adding delay loops will help prove the EFIStub is innocent. > > > > Didn't change anything. > Just closing the loop on this... > Okay, so just to clarify, a delay before ExitBootServices doesn't cause the > error to show up before ExitBootServices, so the error hasn't occurred prior to > this point. Correct. I have never seen the error before ExitBootServices. > And a delay after ExitBootServices allows us to see the error before we exit > into head.S. (this rules out a bug in head.S) > The delays should be long enough to tell us this slimpro isn't generating the > error records N seconds after reset. No delay needed after ExitBootServices. The error would be there right after the call returns back to stub. > > Given this I agree we should disable_hest based on the DMI platform name and the > UEFI version number. (it may be earlier firmware didn't have this bug). > > > I don't have anything to test this on, so I've picked the DMI strings out the > demsg output on that bugzilla entry. Any chance you could give it a test? > > > > > Are redhat able to rebuild UEFI on these systems? (Can it be fixed?) > > > https://bugzilla.redhat.com/show_bug.cgi?id=1285107 is about the m400 > > > description of the GIC, comments 15 and 16 show a UEFI patch to something other > > > than the upstream platforms tree[0], and new firmware being tested. > > > (although this may be wishful thinking) > > > > HPe would respond to bug reports until m400 reached EOL. They have been pretty > > clear that no more firmware updates will be done. > > Thanks, it was a bit murky from that ticket... > > > Thanks for doing this! > > James -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
