Kernel v5.14 has various changes to optimize unaligned memory accesses, e.g. commit 0652035a5794 ("asm-generic: unaligned: remove byteshift helpers").
Those changes triggered an unalignment-exception and thus crashed the bootloader on parisc because the unaligned "output_len" variable now suddenly was read word-wise while it was read byte-wise in the past.
Fix this issue by declaring the external output_len variable as char which then forces the compiler to generate byte-accesses.
Signed-off-by: Helge Deller deller@gmx.de Cc: Arnd Bergmann arnd@kernel.org Cc: John David Anglin dave.anglin@bell.net Bug: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102162 Fixes: 8c031ba63f8f ("parisc: Unbreak bootloader due to gcc-7 optimizations") Fixes: 0652035a5794 ("asm-generic: unaligned: remove byteshift helpers") Cc: stable@vger.kernel.org # v5.14+ --- arch/parisc/boot/compressed/misc.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/parisc/boot/compressed/misc.c b/arch/parisc/boot/compressed/misc.c index 2d395998f524..7ee49f5881d1 100644 --- a/arch/parisc/boot/compressed/misc.c +++ b/arch/parisc/boot/compressed/misc.c @@ -26,7 +26,7 @@ extern char input_data[]; extern int input_len; /* output_len is inserted by the linker possibly at an unaligned address */ -extern __le32 output_len __aligned(1); +extern char output_len; extern char _text, _end; extern char _bss, _ebss; extern char _startcode_end; -- 2.31.1