The early init code maps the kernel image using statically allocated page tables. This means that we can only allow Image to be placed such that we can map its entire static footprint using a single table entry at all but the lowest level. So update the documentation to reflect that the Image should not cross a 512 MB boundary, which ensures the above on both 4k and 64k pages kernels. Reviewed-by: Mark Rutland <mark.rutland@xxxxxxx> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx> --- Documentation/arm64/booting.txt | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/Documentation/arm64/booting.txt b/Documentation/arm64/booting.txt index ab5a90adece3..5949bdbe7aac 100644 --- a/Documentation/arm64/booting.txt +++ b/Documentation/arm64/booting.txt @@ -115,8 +115,9 @@ The Image must be placed text_offset bytes from a 2MB aligned base address near the start of usable system RAM and called there. Memory below that base address is currently unusable by Linux, and therefore it is strongly recommended that this location is the start of system RAM. -At least image_size bytes from the start of the image must be free for -use by the kernel. +The physical memory region consisting of image_size bytes counting from +the start of the image must be free for use by the kernel, and must not +cross a 512 MB physical alignment boundary. Any memory described to the kernel (even that below the 2MB aligned base address) which is not marked as reserved from the kernel e.g. with a -- 1.8.3.2 -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
