On Thu, 7 Nov 2024, tglozar@xxxxxxxxxx wrote:
> From: Tomas Glozar <tglozar@xxxxxxxxxx>
>
> Add test to detect the presence of libcpupower on the system, allowing
> to conditionally build features that depend on it.
>
> The test uses a similar mechanism to the Linux kernel's tools' feature
> detection: a small C program using the library is compiled, and based on
> the success of the compilation, the presence of the library is
> determined.
>
> Signed-off-by: Tomas Glozar <tglozar@xxxxxxxxxx>
This seems overly complicated, how about just doing
ldconfig -p | grep -q libcpupower
if it returns 0, the lib is there, if it returns 1, it's not there.
This is the mechanism that perf uses, you can see in
tools/perf/Makefile.config
ifneq ($(shell ldconfig -p | grep libasan >/dev/null 2>&1; echo $$?), 0)
$(error No libasan found, please install libasan)
endif
> ---
> Makefile | 11 +++++++++++
> feature/Makefile | 12 ++++++++++++
> feature/test-feature.mak | 4 ++++
> feature/test-libcpupower.c | 8 ++++++++
> 4 files changed, 35 insertions(+)
> create mode 100644 feature/Makefile
> create mode 100644 feature/test-feature.mak
> create mode 100644 feature/test-libcpupower.c
>
> diff --git a/Makefile b/Makefile
> index e2f8579..1f698cf 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -1,4 +1,6 @@
> # SPDX-License-Identifier: GPL-2.0-or-later
> +include feature/test-feature.mak
> +
> VERSION = 2.7
> CC = $(CROSS_COMPILE)gcc
> AR = $(CROSS_COMPILE)ar
> @@ -37,6 +39,15 @@ LDFLAGS ?=
>
> PYLIB ?= $(shell python3 -m get_pylib)
>
> +# Check for optional libcpupower dependency
> +ifeq ($(call test-feature,libcpupower), 0)
> +CPPFLAGS += -DHAVE_LIBCPUPOWER_SUPPORT
> +LDFLAGS += -lcpupower
> +else
> +$(warning libcpupower is missing, building without --deepest-idle-state support.)
> +$(warning Please install libcpupower-dev/kernel-tools-libs-devel)
> +endif
> +
> # Check for errors, such as python3 not available
> ifeq (${PYLIB},)
> undefine PYLIB
> diff --git a/feature/Makefile b/feature/Makefile
> new file mode 100644
> index 0000000..085e3a9
> --- /dev/null
> +++ b/feature/Makefile
> @@ -0,0 +1,12 @@
> +# SPDX-License-Identifier: GPL-2.0-or-later
> +all: feature-libcpupower
> +
> +feature-libcpupower: $(OBJDIR)/test-libcpupower.o
> +
> +$(OBJDIR)/test-libcpupower.o: feature/test-libcpupower.c
> + @$(CC) $(CFLAGS) $(CPPFLAGS) $< -lcpupower -o $@
> +
> +.PHONY: clean
> +
> +clean:
> + rm -f $(OBJDIR)/test-*.o
> diff --git a/feature/test-feature.mak b/feature/test-feature.mak
> new file mode 100644
> index 0000000..fffddef
> --- /dev/null
> +++ b/feature/test-feature.mak
> @@ -0,0 +1,4 @@
> +# SPDX-License-Identifier: GPL-2.0-or-later
> +define test-feature
> +$(shell $(MAKE) OBJDIR=$(OBJDIR) -f feature/Makefile feature-$1 clean >/dev/null 2>/dev/null; echo $$?)
> +endef
> diff --git a/feature/test-libcpupower.c b/feature/test-libcpupower.c
> new file mode 100644
> index 0000000..cd16269
> --- /dev/null
> +++ b/feature/test-libcpupower.c
> @@ -0,0 +1,8 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +#include <cpuidle.h>
> +
> +int main(void)
> +{
> + int rv = cpuidle_state_count(0);
> + return rv;
> +}
> --
> 2.47.0
>
>
>
