Ed Swierk <eswi...@skyportsystems.com> writes: > On Wed, Jul 13, 2016 at 10:36 AM, Jason Gunthorpe > <jguntho...@obsidianresearch.com> wrote: >> I think your bios is broken? > > The BIOS is broken in many ways. I already have to pass > memmap=256M$0x80000000, otherwise PCIe extended config space > (MMCONFIG) is inaccessible. Also I found memmap=0x7000$0x7a7d0000 > works around "APEI: Can not request [mem 0x7a7d0018-0x7a7d0067] for > APEI ERST registers", as the BIOS seems to be mistakenly reserving > 0x7b7d0000-7b7d7000 instead. > >> A working BIOS will look like this: >> >> $ cat /proc/iomem | grep -i fed400 >> fed40000-fed44fff : pnp 00:00 >> >> It sets aside the struct resource during pnp: >> >> [ 0.097318] pnp: PnP ACPI init >> [ 0.097366] system 00:00: [mem 0xfed40000-0xfed44fff] has been reserved >> >> What did your system do? >> >> You should see prints like this: >> >> printk(KERN_DEBUG >> "e820: reserve RAM buffer [mem %#010llx-%#010llx]\n", >> start, end); >> >> Which only happen if E820_RAM is set, which is certainly not right for >> TPM memory. > > On my system I see > > e820: reserve RAM buffer [mem 0x0009b000-0x0009ffff] > e820: reserve RAM buffer [mem 0x75b02000-0x77ffffff] > e820: reserve RAM buffer [mem 0x7a1f6000-0x7bffffff] > e820: reserve RAM buffer [mem 0x7b800000-0x7bffffff] > e820: reserve RAM buffer [mem 0xfed30000-0xffffffff] > e820: reserve RAM buffer [mem 0x505deb000-0x507ffffff] > > which doesn't make a whole lot of sense, as several of those areas > overlap each other, never mind devices. > >> I don't know what kernel convention is to handle these sorts of >> defects? >> >> Is the use of the memmap kernel command line an appropriate work >> around? > > It works for me, though I would like to know if there's another > approach.
There is always poke your BIOS vendor until they deliver code that is not so b0rked it can not be used. You can also add a quirk based on the BIOS's mainboard identification string that fixes up the data provided by the BIOS. I remember a fair number of those dealing with reboot behavior and the like. Eric
