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| author | Quentin Monnet <quentin@isovalent.com> | 2021-10-06 14:10:49 +0300 |
|---|---|---|
| committer | Andrii Nakryiko <andrii@kernel.org> | 2021-10-06 22:34:02 +0300 |
| commit | 929bef467771d4d5a22b9edb51a2025dc0e49113 (patch) | |
| tree | e33de0738babed1771644a310480924107c8efdc /samples/bpf | |
| parent | 90982e13561e0d8df91d49658d3bf068ae9f2dff (diff) | |
| download | linux-929bef467771d4d5a22b9edb51a2025dc0e49113.tar.xz | |
bpf: Use $(pound) instead of \# in Makefiles
Recent-ish versions of make do no longer consider number signs ("#") as
comment symbols when they are inserted inside of a macro reference or in
a function invocation. In such cases, the symbols should not be escaped.
There are a few occurrences of "\#" in libbpf's and samples' Makefiles.
In the former, the backslash is harmless, because grep associates no
particular meaning to the escaped symbol and reads it as a regular "#".
In samples' Makefile, recent versions of make will pass the backslash
down to the compiler, making the probe fail all the time and resulting
in the display of a warning about "make headers_install" being required,
even after headers have been installed.
A similar issue has been addressed at some other locations by commit
9564a8cf422d ("Kbuild: fix # escaping in .cmd files for future Make").
Let's address it for libbpf's and samples' Makefiles in the same
fashion, by using a "$(pound)" variable (pulled from
tools/scripts/Makefile.include for libbpf, or re-defined for the
samples).
Reference for the change in make:
https://git.savannah.gnu.org/cgit/make.git/commit/?id=c6966b323811c37acedff05b57
Fixes: 2f3830412786 ("libbpf: Make libbpf_version.h non-auto-generated")
Fixes: 07c3bbdb1a9b ("samples: bpf: print a warning about headers_install")
Signed-off-by: Quentin Monnet <quentin@isovalent.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20211006111049.20708-1-quentin@isovalent.com
Diffstat (limited to 'samples/bpf')
| -rw-r--r-- | samples/bpf/Makefile | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile index 4dc20be5fb96..a5783749ec15 100644 --- a/samples/bpf/Makefile +++ b/samples/bpf/Makefile @@ -3,6 +3,8 @@ BPF_SAMPLES_PATH ?= $(abspath $(srctree)/$(src)) TOOLS_PATH := $(BPF_SAMPLES_PATH)/../../tools +pound := \# + # List of programs to build tprogs-y := test_lru_dist tprogs-y += sock_example @@ -232,7 +234,7 @@ endif # Don't evaluate probes and warnings if we need to run make recursively ifneq ($(src),) -HDR_PROBE := $(shell printf "\#include <linux/types.h>\n struct list_head { int a; }; int main() { return 0; }" | \ +HDR_PROBE := $(shell printf "$(pound)include <linux/types.h>\n struct list_head { int a; }; int main() { return 0; }" | \ $(CC) $(TPROGS_CFLAGS) $(TPROGS_LDFLAGS) -x c - \ -o /dev/null 2>/dev/null && echo okay) |