On Thu, Dec 05, 2013 at 02:43:23PM +0000, Mark Salter wrote: > On Thu, 2013-12-05 at 14:18 +0000, Catalin Marinas wrote: > > On Fri, Nov 29, 2013 at 10:05:10PM +0000, Mark Salter wrote: > > > This patch adds PE/COFF header fields to the start of the Image > > > so that it appears as an EFI application to EFI firmware. An EFI > > > stub is included to allow direct booting of the kernel Image. Due > > > to EFI firmware limitations, only little endian kernels with 4K > > > page sizes are supported at this time. > > > > I don't fully understand the EFI firmware limitations but for big endian > > we could have the EFI_STUB wrapper in little endian and get the kernel > > to switch to big endian once booted. The image header should always be > > little endian. > > That would be fun. :) You'd also have to switch back and forth to make > EFI runtime services calls. OK, we'll have to live with this restriction. > > And I have to dig further into the 4K limitation (or you could give a > > quick summary ;)). > > Just that the current UEFI spec mandates 4K pages for UEFI. So if UEFI > maps two 4k pages with different attributes and those two pages are > within the same 64k kernel page, there'd be a problem. I'd be better if > UEFI used 64k pages, then the kernel could easily use 4k or 64k. For server space, we may see some people asking for 64K pages. But I don't know whether there are any UEFI plans here. Thanks. -- Catalin -- 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
