From: Ard Biesheuvel ardb@kernel.org
[ Commit decd347c2a75d32984beb8807d470b763a53b542 upstream ]
Commit
8117961d98fb2 ("x86/efi: Disregard setup header of loaded image")
dropped the memcopy of the image's setup header into the boot_params struct provided to the core kernel, on the basis that EFI boot does not need it and should rely only on a single protocol to interface with the boot chain. It is also a prerequisite for being able to increase the section alignment to 4k, which is needed to enable memory protections when running in the boot services.
So only the setup_header fields that matter to the core kernel are populated explicitly, and everything else is ignored. One thing was overlooked, though: the initrd_addr_max field in the setup_header is not used by the core kernel, but it is used by the EFI stub itself when it loads the initrd, where its default value of INT_MAX is used as the soft limit for memory allocation.
This means that, in the old situation, the initrd was virtually always loaded in the lower 2G of memory, but now, due to initrd_addr_max being 0x0, the initrd may end up anywhere in memory. This should not be an issue principle, as most systems can deal with this fine. However, it does appear to tickle some problems in older UEFI implementations, where the memory ends up being corrupted, resulting in errors when unpacking the initramfs.
So set the initrd_addr_max field to INT_MAX like it was before.
Fixes: 8117961d98fb2 ("x86/efi: Disregard setup header of loaded image") Reported-by: Radek Podgorny radek@podgorny.cz Closes: https://lore.kernel.org/all/a99a831a-8ad5-4cb0-bff9-be637311f771@podgorny.cz Signed-off-by: Ard Biesheuvel ardb@kernel.org --- drivers/firmware/efi/libstub/x86-stub.c | 1 + 1 file changed, 1 insertion(+)
diff --git a/drivers/firmware/efi/libstub/x86-stub.c b/drivers/firmware/efi/libstub/x86-stub.c index c592ecd40dab..1f5edcb6339a 100644 --- a/drivers/firmware/efi/libstub/x86-stub.c +++ b/drivers/firmware/efi/libstub/x86-stub.c @@ -453,6 +453,7 @@ efi_status_t __efiapi efi_pe_entry(efi_handle_t handle, hdr->vid_mode = 0xffff;
hdr->type_of_loader = 0x21; + hdr->initrd_addr_max = INT_MAX;
/* Convert unicode cmdline to ascii */ cmdline_ptr = efi_convert_cmdline(image, &options_size);