arm64: mm: Ensure tail of unaligned initrd is reserved

BugLink: https://bugs.launchpad.net/bugs/1830929
commit d4d18e3ec6091843f607e8929a56723e28f393a6 upstream.

In the event that the start address of the initrd is not aligned, but
has an aligned size, the base + size will not cover the entire initrd
image and there is a chance that the kernel will corrupt the tail of the
image.

By aligning the end of the initrd to a page boundary and then
subtracting the adjusted start address the memblock reservation will
cover all pages that contains the initrd.

Fixes: c756c592e442 ("arm64: Utilize phys_initrd_start/phys_initrd_size")
Cc: stable@vger.kernel.org
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>

diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
index 7205a9085b4de23edf68ae194b20c54ceacc029e..c9411774555d0f42d1057655708122900b7956ae 100644 (file)
--- a/arch/arm64/mm/init.c
+++ b/arch/arm64/mm/init.c
@@ -406,7 +406,7 @@ void __init arm64_memblock_init(void)
                 * Otherwise, this is a no-op
                 */
                u64 base = phys_initrd_start & PAGE_MASK;
-               u64 size = PAGE_ALIGN(phys_initrd_size);
+               u64 size = PAGE_ALIGN(phys_initrd_start + phys_initrd_size) - base;
 
                /*
                 * We can only add back the initrd memory if we don't end up