selftests/powerpc: Add tests of PMU EBBs

The Power8 Performance Monitor Unit (PMU) has a new feature called Event
Based Branches (EBB). This commit adds tests of the kernel API for using
EBBs.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

34 files changed, 3913 insertions, 4 deletions

diff --git a/tools/testing/selftests/powerpc/pmu/Makefile b/tools/testing/selftests/powerpc/pmu/Makefile
index 7216f0091655..b9ff0db42c79 100644
--- a/tools/testing/selftests/powerpc/pmu/Makefile
+++ b/tools/testing/selftests/powerpc/pmu/Makefile
@@ -4,7 +4,7 @@ noarg:
 PROGS := count_instructions
 EXTRA_SOURCES := ../harness.c event.c
 
-all: $(PROGS)
+all: $(PROGS) sub_all
 
 $(PROGS): $(EXTRA_SOURCES)
 
@@ -12,12 +12,30 @@ $(PROGS): $(EXTRA_SOURCES)
 count_instructions: loop.S count_instructions.c $(EXTRA_SOURCES)
         $(CC) $(CFLAGS) -m64 -o $@ $^
 
-run_tests: all
+run_tests: all sub_run_tests
         @-for PROG in $(PROGS); do \
                 ./$$PROG; \
         done;
 
-clean:
+clean: sub_clean
         rm -f $(PROGS) loop.o
 
-.PHONY: all run_tests clean
+
+SUB_TARGETS = ebb
+
+sub_all:
+        @for TARGET in $(SUB_TARGETS); do \
+                $(MAKE) -C $$TARGET all; \
+        done;
+
+sub_run_tests: all
+        @for TARGET in $(SUB_TARGETS); do \
+                $(MAKE) -C $$TARGET run_tests; \
+        done;
+
+sub_clean:
+        @for TARGET in $(SUB_TARGETS); do \
+                $(MAKE) -C $$TARGET clean; \
+        done;
+
+.PHONY: all run_tests clean sub_all sub_run_tests sub_clean
diff --git a/tools/testing/selftests/powerpc/pmu/ebb/Makefile b/tools/testing/selftests/powerpc/pmu/ebb/Makefile
new file mode 100644
index 000000000000..edbba2affc2c
--- /dev/null
+++ b/tools/testing/selftests/powerpc/pmu/ebb/Makefile
@@ -0,0 +1,32 @@
+noarg:
+        $(MAKE) -C ../../
+
+# The EBB handler is 64-bit code and everything links against it
+CFLAGS += -m64
+
+PROGS := reg_access_test event_attributes_test cycles_test      \
+         cycles_with_freeze_test pmc56_overflow_test            \
+         ebb_vs_cpu_event_test cpu_event_vs_ebb_test            \
+         cpu_event_pinned_vs_ebb_test task_event_vs_ebb_test    \
+         task_event_pinned_vs_ebb_test multi_ebb_procs_test     \
+         multi_counter_test pmae_handling_test                  \
+         close_clears_pmcc_test instruction_count_test          \
+         fork_cleanup_test ebb_on_child_test                    \
+         ebb_on_willing_child_test back_to_back_ebbs_test       \
+         lost_exception_test no_handler_test
+
+all: $(PROGS)
+
+$(PROGS): ../../harness.c ../event.c ../lib.c ebb.c ebb_handler.S trace.c
+
+instruction_count_test: ../loop.S
+
+lost_exception_test: ../lib.c
+
+run_tests: all
+        @-for PROG in $(PROGS); do \
+                ./$$PROG; \
+        done;
+
+clean:
+        rm -f $(PROGS)
diff --git a/tools/testing/selftests/powerpc/pmu/ebb/back_to_back_ebbs_test.c b/tools/testing/selftests/powerpc/pmu/ebb/back_to_back_ebbs_test.c
new file mode 100644
index 000000000000..66ea765c0e72
--- /dev/null
+++ b/tools/testing/selftests/powerpc/pmu/ebb/back_to_back_ebbs_test.c
@@ -0,0 +1,106 @@
+/*
+ * Copyright 2014, Michael Ellerman, IBM Corp.
+ * Licensed under GPLv2.
+ */
+
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "ebb.h"
+
+
+#define NUMBER_OF_EBBS  50
+
+/*
+ * Test that if we overflow the counter while in the EBB handler, we take
+ * another EBB on exiting from the handler.
+ *
+ * We do this by counting with a stupidly low sample period, causing us to
+ * overflow the PMU while we're still in the EBB handler, leading to another
+ * EBB.
+ *
+ * We get out of what would otherwise be an infinite loop by leaving the
+ * counter frozen once we've taken enough EBBs.
+ */
+
+static void ebb_callee(void)
+{
+        uint64_t siar, val;
+
+        val = mfspr(SPRN_BESCR);
+        if (!(val & BESCR_PMEO)) {
+                ebb_state.stats.spurious++;
+                goto out;
+        }
+
+        ebb_state.stats.ebb_count++;
+        trace_log_counter(ebb_state.trace, ebb_state.stats.ebb_count);
+
+        /* Resets the PMC */