diff options
Diffstat (limited to 'arch/arm/boot/compressed/head.S')
| -rw-r--r-- | arch/arm/boot/compressed/head.S | 19 |
1 files changed, 18 insertions, 1 deletions
diff --git a/arch/arm/boot/compressed/head.S b/arch/arm/boot/compressed/head.S index c41a793b519c..55a353243a90 100644 --- a/arch/arm/boot/compressed/head.S +++ b/arch/arm/boot/compressed/head.S @@ -168,9 +168,26 @@ not_angel: .text #ifdef CONFIG_AUTO_ZRELADDR - @ determine final kernel image address + /* + * Find the start of physical memory. As we are executing + * without the MMU on, we are in the physical address space. + * We just need to get rid of any offset by aligning the + * address. + * + * This alignment is a balance between the requirements of + * different platforms - we have chosen 128MB to allow + * platforms which align the start of their physical memory + * to 128MB to use this feature, while allowing the zImage + * to be placed within the first 128MB of memory on other + * platforms. Increasing the alignment means we place + * stricter alignment requirements on the start of physical + * memory, but relaxing it means that we break people who + * are already placing their zImage in (eg) the top 64MB + * of this range. + */ mov r4, pc and r4, r4, #0xf8000000 + /* Determine final kernel image address. */ add r4, r4, #TEXT_OFFSET #else ldr r4, =zreladdr |