[RFC PATCH v2 4/7] tools: build perf in tools_build

[Sasha Levin <sashal@kernel.org>]

Add CONFIG_TOOLS_BUILD_PERF. perf is built as it is built standalone,
with optional features enabled when their libraries are installed, and
with perf's WERROR setting following CONFIG_WERROR. The feature table is
left out of the kernel build log.

CONFIG_TOOLS_BUILD_PERF_MINIMAL builds it with MINIMAL=1 instead, which
turns every optional feature off, so the result does not depend on the
build machine. allmodconfig and allyesconfig turn it on.

Assisted-by: LLM
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 tools/Kconfig         | 16 ++++++++++++++++
 tools/Makefile.kbuild | 10 ++++++++++
 2 files changed, 26 insertions(+)

diff --git a/tools/Kconfig b/tools/Kconfig
index 2d05c8e593e21..4f13e3b104377 100644
--- a/tools/Kconfig
+++ b/tools/Kconfig
@@ -60,6 +60,22 @@ config TOOLS_BUILD_IIO
 	help
 	  Build tools/iio (lsiio, iio_event_monitor, iio_generic_buffer).
 
+config TOOLS_BUILD_PERF
+	bool "perf"
+	help
+	  Build tools/perf. As in a standalone perf build, optional
+	  features are enabled when the libraries they need are installed.
+
+config TOOLS_BUILD_PERF_MINIMAL
+	bool "Build perf with all optional features disabled"
+	depends on TOOLS_BUILD_PERF
+	help
+	  Build perf with MINIMAL=1, which turns off every optional
+	  feature, so that the result does not depend on which libraries
+	  the build machine has installed. allmodconfig and allyesconfig
+	  turn this on, which keeps their builds the same on every
+	  machine.
+
 config TOOLS_BUILD_SPI
 	bool "SPI tools"
 	help
diff --git a/tools/Makefile.kbuild b/tools/Makefile.kbuild
index 8cfa7f80039cd..4b3ea73bc8ab9 100644
--- a/tools/Makefile.kbuild
+++ b/tools/Makefile.kbuild
@@ -79,6 +79,16 @@ PHONY += $(tool-targets)
 $(tool-targets): tool-%: FORCE
 	$(call build,$(outdir)/$*,-C $(toolsdir)/$* O=$(outdir)/$* CC='$(call escsq,$(tools-cc))',,TOOLS_BUILD_$(shell echo $* | tr a-z A-Z))
 
+# perf, without the feature table in the kernel build log
+perf-flags := CC='$(call escsq,$(tools-cc))' FEATURE_DISPLAY= WERROR=$(if $(CONFIG_WERROR),1,0)
+perf-flags-$(CONFIG_TOOLS_BUILD_PERF_MINIMAL) += MINIMAL=1
+
+__tools_build: $(if $(CONFIG_TOOLS_BUILD_PERF),perf)
+
+PHONY += perf
+perf: FORCE
+	$(call build,$(outdir)/perf,-C $(toolsdir)/perf -f Makefile.perf O=$(outdir)/perf $(perf-flags) $(perf-flags-y),,TOOLS_BUILD_PERF)
+
 PHONY += FORCE
 FORCE:
 
-- 
2.53.0