The jevents command expects all json files to be organized under a
single directory. When generating json files from scripts (to reduce
laborious copy and paste in the json) we don't want to generate the
json into the source directory if there is an OUTPUT directory
specified. This change adds a GEN_JSON for this case where the
GEN_JSON copies the JSON files to OUTPUT, only when OUTPUT is
specified. The Makefile.perf clean code is updated to clean up this
directory when present.

This patch is part of:
https://lore.kernel.org/lkml/20240926173554.404411-12-irogers@google.com/
which was similarly adding support for generating json in scripts for
the consumption of jevents.py.

Signed-off-by: Ian Rogers <irogers@google.com>
---
 tools/perf/Makefile.perf    | 21 ++++++++++++++++-----
 tools/perf/pmu-events/Build | 18 ++++++++++++------
 2 files changed, 28 insertions(+), 11 deletions(-)

diff --git a/tools/perf/Makefile.perf b/tools/perf/Makefile.perf
index e2150acc2c13..cc1635335586 100644
--- a/tools/perf/Makefile.perf
+++ b/tools/perf/Makefile.perf
@@ -1272,9 +1272,24 @@ endif # CONFIG_PERF_BPF_SKEL
 bpf-skel-clean:
 	$(call QUIET_CLEAN, bpf-skel) $(RM) -r $(SKEL_TMP_OUT) $(SKELETONS) $(SKEL_OUT)/vmlinux.h
 
+pmu-events-clean:
+ifeq ($(OUTPUT),)
+	$(call QUIET_CLEAN, pmu-events) $(RM) \
+		pmu-events/pmu-events.c \
+		pmu-events/metric_test.log \
+		pmu-events/test-empty-pmu-events.c \
+		pmu-events/empty-pmu-events.log
+else # When an OUTPUT directory is present, clean up the copied pmu-events/arch directory.
+	$(call QUIET_CLEAN, pmu-events) $(RM) -r $(OUTPUT)pmu-events/arch \
+		$(OUTPUT)pmu-events/pmu-events.c \
+		$(OUTPUT)pmu-events/metric_test.log \
+		$(OUTPUT)pmu-events/test-empty-pmu-events.c \
+		$(OUTPUT)pmu-events/empty-pmu-events.log
+endif
+
 clean:: $(LIBAPI)-clean $(LIBBPF)-clean $(LIBSUBCMD)-clean $(LIBSYMBOL)-clean $(LIBPERF)-clean \
 		arm64-sysreg-defs-clean fixdep-clean python-clean bpf-skel-clean \
-		tests-coresight-targets-clean
+		tests-coresight-targets-clean pmu-events-clean
 	$(call QUIET_CLEAN, core-objs)  $(RM) $(LIBPERF_A) $(OUTPUT)perf-archive \
 		$(OUTPUT)perf-iostat $(LANG_BINDINGS)
 	$(Q)find $(or $(OUTPUT),.) -name '*.o' -delete -o -name '*.a' -delete -o \
@@ -1287,10 +1302,6 @@ clean:: $(LIBAPI)-clean $(LIBBPF)-clean $(LIBSUBCMD)-clean $(LIBSYMBOL)-clean $(
 		$(OUTPUT)FEATURE-DUMP $(OUTPUT)util/*-bison* $(OUTPUT)util/*-flex* \
 		$(OUTPUT)util/intel-pt-decoder/inat-tables.c \
 		$(OUTPUT)tests/llvm-src-{base,kbuild,prologue,relocation}.c \
-		$(OUTPUT)pmu-events/pmu-events.c \
-		$(OUTPUT)pmu-events/test-empty-pmu-events.c \
-		$(OUTPUT)pmu-events/empty-pmu-events.log \
-		$(OUTPUT)pmu-events/metric_test.log \
 		$(OUTPUT)$(fadvise_advice_array) \
 		$(OUTPUT)$(fsconfig_arrays) \
 		$(OUTPUT)$(fsmount_arrays) \
diff --git a/tools/perf/pmu-events/Build b/tools/perf/pmu-events/Build
index 32f387d48908..1503a16e662a 100644
--- a/tools/perf/pmu-events/Build
+++ b/tools/perf/pmu-events/Build
@@ -1,7 +1,6 @@
 pmu-events-y	+= pmu-events.o
 JDIR		=  pmu-events/arch/$(SRCARCH)
-JSON		=  $(shell [ -d $(JDIR) ] &&				\
-			find $(JDIR) -name '*.json' -o -name 'mapfile.csv')
+JSON		=  $(shell find pmu-events/arch -name *.json -o -name *.csv)
 JDIR_TEST	=  pmu-events/arch/test
 JSON_TEST	=  $(shell [ -d $(JDIR_TEST) ] &&			\
 			find $(JDIR_TEST) -name '*.json')
@@ -29,13 +28,20 @@ $(PMU_EVENTS_C): $(EMPTY_PMU_EVENTS_C)
 	$(call rule_mkdir)
 	$(Q)$(call echo-cmd,gen)cp $< $@
 else
+# Copy checked-in json for generation.
+$(OUTPUT)pmu-events/arch/%: pmu-events/arch/%
+	$(call rule_mkdir)
+	$(Q)$(call echo-cmd,gen)cp $< $@
+
+GEN_JSON = $(patsubst %,$(OUTPUT)%,$(JSON))
+
 $(METRIC_TEST_LOG): $(METRIC_TEST_PY) $(METRIC_PY)
 	$(call rule_mkdir)
 	$(Q)$(call echo-cmd,test)$(PYTHON) $< 2> $@ || (cat $@ && false)
 
-$(TEST_EMPTY_PMU_EVENTS_C): $(JSON) $(JSON_TEST) $(JEVENTS_PY) $(METRIC_PY) $(METRIC_TEST_LOG)
+$(TEST_EMPTY_PMU_EVENTS_C): $(GEN_JSON) $(JSON_TEST) $(JEVENTS_PY) $(METRIC_PY) $(METRIC_TEST_LOG)
 	$(call rule_mkdir)
-	$(Q)$(call echo-cmd,gen)$(PYTHON) $(JEVENTS_PY) none none pmu-events/arch $@
+	$(Q)$(call echo-cmd,gen)$(PYTHON) $(JEVENTS_PY) none none $(OUTPUT)pmu-events/arch $@
 
 $(EMPTY_PMU_EVENTS_TEST_LOG): $(EMPTY_PMU_EVENTS_C) $(TEST_EMPTY_PMU_EVENTS_C)
 	$(call rule_mkdir)
@@ -63,10 +69,10 @@ $(OUTPUT)%.pylint_log: %
 	$(call rule_mkdir)
 	$(Q)$(call echo-cmd,test)pylint "$<" > $@ || (cat $@ && rm $@ && false)
 
-$(PMU_EVENTS_C): $(JSON) $(JSON_TEST) $(JEVENTS_PY) $(METRIC_PY) $(METRIC_TEST_LOG) \
+$(PMU_EVENTS_C): $(GEN_JSON) $(JSON_TEST) $(JEVENTS_PY) $(METRIC_PY) $(METRIC_TEST_LOG) \
     $(EMPTY_PMU_EVENTS_TEST_LOG) $(PMU_EVENTS_MYPY_TEST_LOGS) $(PMU_EVENTS_PYLINT_TEST_LOGS)
 	$(call rule_mkdir)
-	$(Q)$(call echo-cmd,gen)$(PYTHON) $(JEVENTS_PY) $(JEVENTS_ARCH) $(JEVENTS_MODEL) pmu-events/arch $@
+	$(Q)$(call echo-cmd,gen)$(PYTHON) $(JEVENTS_PY) $(JEVENTS_ARCH) $(JEVENTS_MODEL) $(OUTPUT)pmu-events/arch $@
 endif
 
 # pmu-events.c file is generated in the OUTPUT directory so it needs a
-- 
2.51.0.268.g9569e192d0-goog