| Message ID | 20211006111049.20708-1-quentin@isovalent.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | bf2819e0b10fbc92f2c9eb4617af79b206bd4356 |
| Delegated to: | BPF |
| Headers | show |
| Series | [bpf-next] bpf: use $(pound) instead of \# in Makefiles | expand |
Hello: This patch was applied to bpf/bpf-next.git (refs/heads/master): On Wed, 6 Oct 2021 12:10:49 +0100 you wrote: > 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. > > [...] Here is the summary with links: - [bpf-next] bpf: use $(pound) instead of \# in Makefiles https://git.kernel.org/bpf/bpf-next/c/bf2819e0b10f You are awesome, thank you! -- Deet-doot-dot, I am a bot. https://korg.docs.kernel.org/patchwork/pwbot.html
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) diff --git a/tools/lib/bpf/Makefile b/tools/lib/bpf/Makefile index 0f766345506f..41e4f78dbad5 100644 --- a/tools/lib/bpf/Makefile +++ b/tools/lib/bpf/Makefile @@ -208,8 +208,8 @@ check_abi: $(OUTPUT)libbpf.so $(VERSION_SCRIPT) exit 1; \ fi -HDR_MAJ_VERSION := $(shell grep -oE '^\#define LIBBPF_MAJOR_VERSION ([0-9]+)$$' libbpf_version.h | cut -d' ' -f3) -HDR_MIN_VERSION := $(shell grep -oE '^\#define LIBBPF_MINOR_VERSION ([0-9]+)$$' libbpf_version.h | cut -d' ' -f3) +HDR_MAJ_VERSION := $(shell grep -oE '^$(pound)define LIBBPF_MAJOR_VERSION ([0-9]+)$$' libbpf_version.h | cut -d' ' -f3) +HDR_MIN_VERSION := $(shell grep -oE '^$(pound)define LIBBPF_MINOR_VERSION ([0-9]+)$$' libbpf_version.h | cut -d' ' -f3) check_version: $(VERSION_SCRIPT) libbpf_version.h @if [ "$(HDR_MAJ_VERSION)" != "$(LIBBPF_MAJOR_VERSION)" ]; then \
Recent-ish versions of make do no longer consider number signs ("#") as comment symbols when they are inserted inside of a macro reference or in a function invocation. In such cases, the symbols should not be escaped. There are a few occurrences of "\#" in libbpf's and samples' Makefiles. In the former, the backslash is harmless, because grep associates no particular meaning to the escaped symbol and reads it as a regular "#". In samples' Makefile, recent versions of make will pass the backslash down to the compiler, making the probe fail all the time and resulting in the display of a warning about "make headers_install" being required, even after headers have been installed. A similar issue has been addressed at some other locations by commit 9564a8cf422d ("Kbuild: fix # escaping in .cmd files for future Make"). Let's address it for libbpf's and samples' Makefiles in the same fashion, by using a "$(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> --- samples/bpf/Makefile | 4 +++- tools/lib/bpf/Makefile | 4 ++-- 2 files changed, 5 insertions(+), 3 deletions(-)