[PATCH] arm64: efi: make sure vmlinux load address aligned on 2MBytes

On Wed, Oct 28, 2015 at 12:11:57PM -0500, Timur Tabi wrote:

On 10/27/2015 09:06 PM, Ard Biesheuvel wrote:

quoted

diff --git a/arch/arm64/kernel/efi-stub.c b/arch/arm64/kernel/efi-stub.c
index 816120ece6bc..a60ce249cfc0 100644
--- a/arch/arm64/kernel/efi-stub.c
+++ b/arch/arm64/kernel/efi-stub.c

@@ -42,7 +42,8 @@
                 * Mustang), we can still place the kernel at the address
                 * 'dram_base + TEXT_OFFSET'.
                 */
-               *image_addr = *reserve_addr = dram_base + TEXT_OFFSET;
+               *image_addr = *reserve_addr = round_up(dram_base, SZ_2M) +
+                                                      TEXT_OFFSET);
                nr_pages = round_up(kernel_memsize, EFI_ALLOC_ALIGN) /
                           EFI_PAGE_SIZE;
                status = efi_call_early(allocate_pages, EFI_ALLOCATE_ADDRESS,

Tested-by: Timur Tabi <redacted>
Tested-by: Shanker Donthineni <redacted>

However, I think this formatting is easier to read:

		*image_addr = *reserve_addr =
			round_up(dram_base, SZ_2M) + TEXT_OFFSET;

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.

Anyway, is there any chance we can get this fix into 4.3?  I'd hate to have
4.3 released knowing that it's broken on our hardware.

If you want something in for 4.3, you'll need to post a new patch in a
separate thread and I'd like to see at least Ard's ack on it.

Will