On Wed, Oct 28, 2015 at 04:02:23PM -0500, Timur Tabi wrote: > On 10/28/2015 12:26 PM, Mark Rutland wrote: > >>>This does make the kernel boot, but we suspect that there may be > >>>another problem. We need to investigate it, but we have a suspicion > >>>that the EFI stub is trying to allocate from the Runtime Data block, > >>>and the alignment adjustment "fixes" the problem by moving the > >>>pointer to Conventional Memory. > >I don't follow. EFI_BOOT_SERVICES.AllocatePages() should only give us > >pages which are available, so it shouldn't ever return pages which are > >runtime data -- it would fail and we'd fall back to efi_low_alloc(). > > > >Could you elaborate? > > So we're still debugging this internally, but it turns out that > dram_base is equal to 0x4000820000, which also happens to be the > start of a Runtime Data block: > > 0x004000820000-0x00400085ffff [Runtime Data |RUN|XP| | | > |WB|WT|WC|UC] > > I think this is not supposed to happen. It's perfectly valid for that to be detected as dram_base, and the stub may call AllocatePages() for that region, but AllocatePages() shouldn't successfully allocate from there. The stub should fall back to efi_low_alloc, walking through the memory map until it finds a large enough region to allocate from, with some subsequent AllocatePages() call eventually succeeding. Is that not what you're seeing? Thanks, Mark. -- To unsubscribe from this list: send the line "unsubscribe linux-efi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
