[PATCH v2 2/2] perf tsc: Declare TSC support from the build system

[Chen Pei]

The "TSC support" subtest of the "Convert perf time to TSC" test decides
whether the architecture is covered by matching compiler macros for
x86_64, i386 and arm64.  That list has to be edited for every new
architecture and can drift apart from the set of architectures that really
provide a counter.

Declare the capability where the implementation is, following the
PERF_HAVE_JITDUMP pattern: an architecture with a usable counter sets
PERF_HAVE_RDTSC in its arch Makefile, Makefile.config turns it into
-DHAVE_RDTSC, and the test keys off that.

x86 and arm64 keep the same behaviour, riscv starts running the subtest
where the previous patch defines rdtsc().

Signed-off-by: Chen Pei <cp0613 at linux.alibaba.com>
---
Changes in v2:
- Declare the capability through the build system instead of a weak
  arch__rdtsc_supported() hook.

 tools/perf/Makefile.config          |  4 ++++
 tools/perf/arch/arm64/Makefile      |  1 +
 tools/perf/arch/riscv/Makefile      |  1 +
 tools/perf/arch/x86/Makefile        |  1 +
 tools/perf/tests/perf-time-to-tsc.c | 19 ++++---------------
 5 files changed, 11 insertions(+), 15 deletions(-)

diff --git a/tools/perf/Makefile.config b/tools/perf/Makefile.config
index 4d5993da9f94..f1b3bf208231 100644
--- a/tools/perf/Makefile.config
+++ b/tools/perf/Makefile.config
@@ -618,6 +618,10 @@ ifdef PERF_HAVE_JITDUMP
   endif
 endif
 
+ifeq ($(PERF_HAVE_RDTSC),1)
+  CFLAGS += -DHAVE_RDTSC
+endif
+
 ifeq ($(SRCARCH),powerpc)
   ifndef NO_LIBDW
     CFLAGS += -DHAVE_SKIP_CALLCHAIN_IDX
diff --git a/tools/perf/arch/arm64/Makefile b/tools/perf/arch/arm64/Makefile
index 44cc3f023318..b9cd559065d6 100644
--- a/tools/perf/arch/arm64/Makefile
+++ b/tools/perf/arch/arm64/Makefile
@@ -1,2 +1,3 @@
 # SPDX-License-Identifier: GPL-2.0
 PERF_HAVE_JITDUMP := 1
+PERF_HAVE_RDTSC := 1
diff --git a/tools/perf/arch/riscv/Makefile b/tools/perf/arch/riscv/Makefile
index 44cc3f023318..8036bf55da8e 100644
--- a/tools/perf/arch/riscv/Makefile
+++ b/tools/perf/arch/riscv/Makefile
@@ -1,2 +1,3 @@
 # SPDX-License-Identifier: GPL-2.0
 PERF_HAVE_JITDUMP := 1
+PERF_HAVE_RDTSC := $(IS_64_BIT)
diff --git a/tools/perf/arch/x86/Makefile b/tools/perf/arch/x86/Makefile
index 44cc3f023318..b9cd559065d6 100644
--- a/tools/perf/arch/x86/Makefile
+++ b/tools/perf/arch/x86/Makefile
@@ -1,2 +1,3 @@
 # SPDX-License-Identifier: GPL-2.0
 PERF_HAVE_JITDUMP := 1
+PERF_HAVE_RDTSC := 1
diff --git a/tools/perf/tests/perf-time-to-tsc.c b/tools/perf/tests/perf-time-to-tsc.c
index f8f71fdd32b1..feb8063f8b59 100644
--- a/tools/perf/tests/perf-time-to-tsc.c
+++ b/tools/perf/tests/perf-time-to-tsc.c
@@ -22,16 +22,6 @@
 #include "tests.h"
 #include "util/sample.h"
 
-/*
- * Except x86_64/i386 and Arm64, other archs don't support TSC in perf.  Just
- * enable the test for x86_64/i386 and Arm64 archs.
- */
-#if defined(__x86_64__) || defined(__i386__) || defined(__aarch64__)
-#define TSC_IS_SUPPORTED 1
-#else
-#define TSC_IS_SUPPORTED 0
-#endif
-
 #define CHECK__(x) {				\
 	while ((x) < 0) {			\
 		pr_debug(#x " failed!\n");	\
@@ -49,11 +39,10 @@
 static int test__tsc_is_supported(struct test_suite *test __maybe_unused,
 				  int subtest __maybe_unused)
 {
-	if (!TSC_IS_SUPPORTED) {
-		pr_debug("Test not supported on this architecture\n");
-		return TEST_SKIP;
-	}
-
+#ifndef HAVE_RDTSC
+	pr_debug("Test not supported on this architecture\n");
+	return TEST_SKIP;
+#endif
 	return TEST_OK;
 }
 
-- 
2.50.1