[PATCH] MIPS: boot: Fix unaligned access with CONFIG_MIPS_RAW_APPENDED_DTB

From: Paul Cercueil
Date: Wed Dec 16 2020 - 18:41:16 EST


The compressed payload is not necesarily 4-byte aligned, at least when
compiling with Clang. In that case, the 4-byte value appended to the
compressed payload that corresponds to the uncompressed kernel image
size must be read using get_unaligned_le().

This fixes Clang-built kernels not booting on MIPS (tested on a Ingenic
JZ4770 board).

Fixes: b8f54f2cde78 ("MIPS: ZBOOT: copy appended dtb to the end of the kernel")
Cc: <stable@xxxxxxxxxxxxxxx> # v4.7
Signed-off-by: Paul Cercueil <paul@xxxxxxxxxxxxxxx>
---
arch/mips/boot/compressed/decompress.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/mips/boot/compressed/decompress.c b/arch/mips/boot/compressed/decompress.c
index c61c641674e6..47c07990432b 100644
--- a/arch/mips/boot/compressed/decompress.c
+++ b/arch/mips/boot/compressed/decompress.c
@@ -117,7 +117,7 @@ void decompress_kernel(unsigned long boot_heap_start)
dtb_size = fdt_totalsize((void *)&__appended_dtb);

/* last four bytes is always image size in little endian */
- image_size = le32_to_cpup((void *)&__image_end - 4);
+ image_size = get_unaligned_le32((void *)&__image_end - 4);

/* copy dtb to where the booted kernel will expect it */
memcpy((void *)VMLINUX_LOAD_ADDRESS_ULL + image_size,
--
2.29.2