Buidling `raid6test` on Ubuntu 21.10 (ppc64le) with GNU Make 4.3 shows the errors below: $ cd lib/raid6/test/ $ make <stdin>:1:1: error: stray ‘\’ in program <stdin>:1:2: error: stray ‘#’ in program <stdin>:1:11: error: expected ‘=’, ‘,’, ‘;’, ‘asm’ or ‘__attribute__’ before ‘<’ token cp -f ../int.uc int.uc awk -f ../unroll.awk -vN=1 < int.uc > int1.c gcc -I.. -I ../../../include -g -O2 -c -o int1.o int1.c awk -f ../unroll.awk -vN=2 < int.uc > int2.c gcc -I.. -I ../../../include -g -O2 -c -o int2.o int2.c awk -f ../unroll.awk -vN=4 < int.uc > int4.c gcc -I.. -I ../../../include -g -O2 -c -o int4.o int4.c awk -f ../unroll.awk -vN=8 < int.uc > int8.c gcc -I.. -I ../../../include -g -O2 -c -o int8.o int8.c awk -f ../unroll.awk -vN=16 < int.uc > int16.c gcc -I.. -I ../../../include -g -O2 -c -o int16.o int16.c awk -f ../unroll.awk -vN=32 < int.uc > int32.c gcc -I.. -I ../../../include -g -O2 -c -o int32.o int32.c rm -f raid6.a ar cq raid6.a int1.o int2.o int4.o int8.o int16.o int32.o recov.o algos.o tables.o ranlib raid6.a gcc -I.. -I ../../../include -g -O2 -o raid6test test.c raid6.a /usr/bin/ld: raid6.a(algos.o):/dev/shm/linux/lib/raid6/test/algos.c:28: multiple definition of `raid6_call'; /scratch/local/ccIJjN8s.o:/dev/shm/linux/lib/raid6/test/test.c:22: first defined here collect2: error: ld returned 1 exit status make: *** [Makefile:72: raid6test] Error 1 The errors come from the `HAS_ALTIVEC` test, which fails, and the POWER optimized versions are not built. That’s also reason nobody noticed on the other architectures. GNU Make 4.3 does not remove the backslash anymore. From the 4.3 release announcment: > * WARNING: Backward-incompatibility! > Number signs (#) appearing inside a macro reference or function invocation > no longer introduce comments and should not be escaped with backslashes: > thus a call such as: > foo := $(shell echo '#') > is legal. Previously the number sign needed to be escaped, for example: > foo := $(shell echo '\#') > Now this latter will resolve to "\#". If you want to write makefiles > portable to both versions, assign the number sign to a variable: > H := \# > foo := $(shell echo '$H') > This was claimed to be fixed in 3.81, but wasn't, for some reason. > To detect this change search for 'nocomment' in the .FEATURES variable. So, do the same as commit 9564a8cf422d ("Kbuild: fix # escaping in .cmd files for future Make") and commit 929bef467771 ("bpf: Use $(pound) instead of \# in Makefiles") and define and use a `$(pound)` variable. Reference for the change in make: https://git.savannah.gnu.org/cgit/make.git/commit/?id=c6966b323811c37acedff05b57 Cc: Matt Brown <matthew.brown.dev@xxxxxxxxx> Signed-off-by: Paul Menzel <pmenzel@xxxxxxxxxxxxx> --- v2: Fix checkpatch.pl errors by adding missing quotes around git commit message summary/title. lib/raid6/test/Makefile | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/lib/raid6/test/Makefile b/lib/raid6/test/Makefile index a4c7cd74cff5..4fb7700a741b 100644 --- a/lib/raid6/test/Makefile +++ b/lib/raid6/test/Makefile @@ -4,6 +4,8 @@ # from userspace. # +pound := \# + CC = gcc OPTFLAGS = -O2 # Adjust as desired CFLAGS = -I.. -I ../../../include -g $(OPTFLAGS) @@ -42,7 +44,7 @@ else ifeq ($(HAS_NEON),yes) OBJS += neon.o neon1.o neon2.o neon4.o neon8.o recov_neon.o recov_neon_inner.o CFLAGS += -DCONFIG_KERNEL_MODE_NEON=1 else - HAS_ALTIVEC := $(shell printf '\#include <altivec.h>\nvector int a;\n' |\ + HAS_ALTIVEC := $(shell printf '$(pound)include <altivec.h>\nvector int a;\n' |\ gcc -c -x c - >/dev/null && rm ./-.o && echo yes) ifeq ($(HAS_ALTIVEC),yes) CFLAGS += -I../../../arch/powerpc/include -- 2.34.1