> On 8 Feb 2017, at 17:03, Mark Rutland <mark.rutland@xxxxxxx> wrote: > >> On Wed, Feb 08, 2017 at 10:35:02AM -0600, Timur Tabi wrote: >> On 02/08/2017 10:29 AM, Ard Biesheuvel wrote: >>>>>>> + status = handle_cmdline_files(sys_table, image, cmdline_ptr, >>>>>>> + "initrd=", dram_base + SZ_512M, >>>>>>> + (unsigned long *)&initrd_addr, >>>>>>> + (unsigned long *)&initrd_size); >>>>> >>>>> So I know this patch is almost three years old, but why is there a >>>>> 512M limit on the initrd size? >>>>> >>> How do you reckon this constitutes a limit? >> >> handle_cmdline_files() calls efi_high_alloc() with that limit. I'm >> still trying to understand all the details myself, but apparently >> our firmware and initrd need to fit within the first 512MB because >> of dram_base + SZ_512M. When we change "dram_base + SZ_512M" to >> "~0", everything works. > > Just to check, how big is that initrd? > > I guess it's possible that there simply isn't sufficient contiguous free > memory in that range, even if the initrd isn't that large. Can you share > the EFI memory map dump from booting with efi=debug? > > We originally needed to restrict this to ensure that the kernel could > map the initrd (and I think the 512M restriction specifically was > inherited from the DTB mapping restriction). Since then, we have relaxed > things in the kernel, and today Documentation/arm64/booting.txt says: > > If an initrd/initramfs is passed to the kernel at boot, it must > reside entirely within a 1 GB aligned physical memory window of > up to 32 GB in size that fully covers the kernel Image as well. > > ... so I think the EFI stub should be able to take advantage of that > relaxation. > > Ard? > Interestingly enough, this code originates on 32-bit ARM, where the linear mapping is only 800 MB so I suspect that may have something to do with it. I agree the stub should simply follow the rules laid out in booting.txt. I think nobody hit this because it is usually GRUB that loads the initrd not the EFI stub-- 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
