Commit 88731c8f authored Jul 29, 2021 by Vasily Gorbik Committed by Heiko Carstens Jul 30, 2021

s390/boot: fix zstd build for -march=z900

zstd decompression uses __builtin_clz() which fails back to __clzdi2()
when the kernel is built for older hardware like z900. This leads to
build failures like the following:
s390x-11.1.0-ld: /devel/src/kernel/arch/s390/boot/compressed/../../../../lib/zstd/bitstream.h:148: undefined reference to `__clzdi2'

Fix that by optionally including lib/clz_ctz.c into the decompressor.

Reported-by: kernel test robot <lkp@intel.com>
Fixes: 7b034d9c ("s390/boot: add zstd support")
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Link: https://lore.kernel.org/r/patch-1.thread-f0f589.git-f0f58936888f.your-ad-here.call-01627564869-ext-2765@work.hours

Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

parent 7561c14d

arch/s390/boot/compressed/Makefile

+1 −0

Original line number	Diff line number	Diff line
		@@ -11,6 +11,7 @@ UBSAN_SANITIZE := n
		KASAN_SANITIZE := n

		obj-y := $(if $(CONFIG_KERNEL_UNCOMPRESSED),,decompressor.o) info.o
		obj-$(CONFIG_KERNEL_ZSTD) += clz_ctz.o
		obj-all := $(obj-y) piggy.o syms.o
		targets := vmlinux.lds vmlinux vmlinux.bin vmlinux.bin.gz vmlinux.bin.bz2
		targets += vmlinux.bin.xz vmlinux.bin.lzma vmlinux.bin.lzo vmlinux.bin.lz4

0 → 100644

+2 −0

Original line number	Diff line number	Diff line
		// SPDX-License-Identifier: GPL-2.0
		#include "../../../../lib/clz_ctz.c"