Commit 73effccb authored by Ard Biesheuvel's avatar Ard Biesheuvel Committed by Will Deacon
Browse files

arm64/efi: do not assume DRAM base is aligned to 2 MB

The current arm64 Image relocation code in the UEFI stub assumes that
the dram_base argument it receives is always a multiple of 2 MB. In
reality, it is simply the lowest start address of all RAM entries in
the UEFI memory map, which means it could be any multiple of 4 KB.

Since the arm64 kernel Image needs to reside TEXT_OFFSET bytes beyond
a 2 MB aligned base, or it will fail to boot, make sure we round dram_base
to 2 MB before using it to calculate the relocation address.

Fixes: e38457c3

 ("arm64: efi: prefer AllocatePages() over efi_low_alloc() for vmlinux")
Reported-by: default avatarTimur Tabi <>
Tested-by: default avatarTimur Tabi <>
Acked-by: default avatarMark Rutland <>
Signed-off-by: default avatarArd Biesheuvel <>
Signed-off-by: default avatarWill Deacon <>
parent 9702970c
......@@ -25,10 +25,20 @@ efi_status_t __init handle_kernel_image(efi_system_table_t *sys_table_arg,
unsigned long kernel_size, kernel_memsize = 0;
unsigned long nr_pages;
void *old_image_addr = (void *)*image_addr;
unsigned long preferred_offset;
* The preferred offset of the kernel Image is TEXT_OFFSET bytes beyond
* a 2 MB aligned base, which itself may be lower than dram_base, as
* long as the resulting offset equals or exceeds it.
preferred_offset = round_down(dram_base, SZ_2M) + TEXT_OFFSET;
if (preferred_offset < dram_base)
preferred_offset += SZ_2M;
/* Relocate the image, if required. */
kernel_size = _edata - _text;
if (*image_addr != (dram_base + TEXT_OFFSET)) {
if (*image_addr != preferred_offset) {
kernel_memsize = kernel_size + (_end - _edata);
......@@ -42,7 +52,7 @@ efi_status_t __init handle_kernel_image(efi_system_table_t *sys_table_arg,
* 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 = preferred_offset;
nr_pages = round_up(kernel_memsize, EFI_ALLOC_ALIGN) /
status = efi_call_early(allocate_pages, EFI_ALLOCATE_ADDRESS,
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