On Fri, 23 Oct, at 10:37:46AM, Ard Biesheuvel wrote: > > After looking at the original (already merged) patch 11/11 again, I > realize this is still not right: the problem is that efi_memory_map's > phys_map member uses a void* type to hold a physical address, which > happens to be correct in the normal case even when phys_addr_t is > larger than void* (like on ARM with LPAE enabled) since the address it > holds is the address of an allocation performed by the firmware, which > only uses 1:1 addressable memory. > > However, overwriting memmap.phys_map with a value produced my > memblock_alloc() is problematic, since the allocation may be above 4 > GB on 32-bit (L)PAE platforms. So the correct way to do this would be > to set the memblock limit to 4GB before memblock_alloc() on 32-bit > platforms, and restore it afterwards. This is a bit of a kludge, > though, and it would be more correct to change the type of > efi_memory_map::phys_map to phys_addr_t, although I don't know what > the potential fallout of that change is. Matt? I think that should be fine. The only potentially tricky situation we could encounter is where 32-bit x86 firmware uses PAE but the kernel is built without support. But that's not something I've ever seen enabled in the firmware and there's a bunch of assumptions in the kernel already that would break in that case. Given that addresses are always 64-bit in the UEFI spec, even on 32-bit platforms, what's the downside of picking u64 instead of phys_addr_t for efi_memory_map::phys_map? -- 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
