perf build: Combine libdw-dwarf-unwind into libdw feature tests

Support in libdw has been present for 10 years so let's simplify the
build logic with a single feature test.

Signed-off-by: Ian Rogers <irogers@google.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Tested-by: Leo Yan <leo.yan@arm.com>
Cc: Anup Patel <anup@brainfault.org>
Cc: Yang Jihong <yangjihong@bytedance.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Shenlin Liang <liangshenlin@eswincomputing.com>
Cc: Nick Terrell <terrelln@fb.com>
Cc: Guilherme Amadio <amadio@gentoo.org>
Cc: Steinar H. Gunderson <sesse@google.com>
Cc: Changbin Du <changbin.du@huawei.com>
Cc: Alexander Lobakin <aleksander.lobakin@intel.com>
Cc: Przemek Kitszel <przemyslaw.kitszel@intel.com>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Guo Ren <guoren@kernel.org>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Cc: Will Deacon <will@kernel.org>
Cc: James Clark <james.clark@linaro.org>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Chen Pei <cp0613@linux.alibaba.com>
Cc: Leo Yan <leo.yan@linux.dev>
Cc: Oliver Upton <oliver.upton@linux.dev>
Cc: Aditya Gupta <adityag@linux.ibm.com>
Cc: Kajol Jain <kjain@linux.ibm.com>
Cc: Athira Rajeev <atrajeev@linux.vnet.ibm.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-riscv@lists.infradead.org
Cc: Bibo Mao <maobibo@loongson.cn>
Cc: John Garry <john.g.garry@oracle.com>
Cc: Atish Patra <atishp@rivosinc.com>
Cc: Dima Kogan <dima@secretsauce.net>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Dr. David Alan Gilbert <linux@treblig.org>
Cc: linux-csky@vger.kernel.org
Link: https://lore.kernel.org/r/20241017001354.56973-6-irogers@google.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>

6 files changed, 18 insertions, 34 deletions

diff --git a/tools/build/Makefile.feature b/tools/build/Makefile.feature
index 6025810cc3469..db3695ec5f838 100644
--- a/tools/build/Makefile.feature
+++ b/tools/build/Makefile.feature
@@ -60,7 +60,6 @@ FEATURE_TESTS_BASIC :=                  \
         reallocarray                    \
         stackprotector-all              \
         timerfd                         \
-        libdw-dwarf-unwind              \
         zlib                            \
         lzma                            \
         get_cpuid                       \
@@ -133,7 +132,6 @@ FEATURE_DISPLAY ?=              \
          libpython              \
          libcrypto              \
          libunwind              \
-         libdw-dwarf-unwind     \
          libcapstone            \
          llvm-perf              \
          zlib                   \
diff --git a/tools/build/feature/Makefile b/tools/build/feature/Makefile
index 7a1c028ce40b5..18f8fef5e8433 100644
--- a/tools/build/feature/Makefile
+++ b/tools/build/feature/Makefile
@@ -52,7 +52,6 @@ FILES=                                          \
          test-pthread-barrier.bin		\
          test-stackprotector-all.bin            \
          test-timerfd.bin                       \
-         test-libdw-dwarf-unwind.bin            \
          test-libbabeltrace.bin                 \
          test-libcapstone.bin			\
          test-compile-32.bin                    \
@@ -317,9 +316,6 @@ $(OUTPUT)test-backtrace.bin:
 $(OUTPUT)test-timerfd.bin:
 	$(BUILD)
 
-$(OUTPUT)test-libdw-dwarf-unwind.bin:
-	$(BUILD) # -ldw provided by $(FEATURE_CHECK_LDFLAGS-libdw-dwarf-unwind)
-
 $(OUTPUT)test-libbabeltrace.bin:
 	$(BUILD) # -lbabeltrace provided by $(FEATURE_CHECK_LDFLAGS-libbabeltrace)
 
diff --git a/tools/build/feature/test-all.c b/tools/build/feature/test-all.c
index d60e072b6eca4..863c825164330 100644
--- a/tools/build/feature/test-all.c
+++ b/tools/build/feature/test-all.c
@@ -98,10 +98,6 @@
 # include "test-stackprotector-all.c"
 #undef main
 
-#define main main_test_libdw_dwarf_unwind
-# include "test-libdw-dwarf-unwind.c"
-#undef main
-
 #define main main_test_zlib
 # include "test-zlib.c"
 #undef main
@@ -202,7 +198,6 @@ int main(int argc, char *argv[])
 	main_test_numa_num_possible_cpus();
 	main_test_timerfd();
 	main_test_stackprotector_all();
-	main_test_libdw_dwarf_unwind();
 	main_test_zlib();
 	main_test_pthread_attr_setaffinity_np();
 	main_test_pthread_barrier();
diff --git a/tools/build/feature/test-libdw-dwarf-unwind.c b/tools/build/feature/test-libdw-dwarf-unwind.c
deleted file mode 100644
index ed03d95056090..0000000000000
--- a/tools/build/feature/test-libdw-dwarf-unwind.c
+++ /dev/null
@@ -1,14 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-
-#include <elfutils/libdwfl.h>
-
-int main(void)
-{
-	/*
-	 * This function is guarded via: __nonnull_attribute__ (1, 2).
-	 * Passing '1' as arguments value. This code is never executed,
-	 * only compiled.
-	 */
-	dwfl_thread_getframes((void *) 1, (void *) 1, NULL);
-	return 0;
-}
diff --git a/tools/build/feature/test-libdw.c b/tools/build/feature/test-libdw.c
index 8d474bd7371b2..793f4ac495140 100644
--- a/tools/build/feature/test-libdw.c
+++ b/tools/build/feature/test-libdw.c
@@ -1,11 +1,28 @@
 // SPDX-License-Identifier: GPL-2.0
 #include <dwarf.h>
 #include <elfutils/libdw.h>
+#include <elfutils/libdwfl.h>
 #include <elfutils/version.h>
 
-int main(void)
+int test_libdw(void)
 {
 	Dwarf *dbg = dwarf_begin(0, DWARF_C_READ);
 
 	return (long)dbg;
 }
+
+int test_libdw_unwind(void)
+{
+	/*
+	 * This function is guarded via: __nonnull_attribute__ (1, 2).
+	 * Passing '1' as arguments value. This code is never executed,
+	 * only compiled.
+	 */
+	dwfl_thread_getframes((void *) 1, (void *) 1, NULL);
+	return 0;
+}
+
+int main(void)
+{
+	return test_libdw() + test_libdw_unwind();
+}
diff --git a/tools/perf/Makefile.config b/tools/perf/Makefile.config
index f1e24c4ae1237..fa59ecce44708 100644
--- a/tools/perf/Makefile.config
+++ b/tools/perf/Makefile.config
@@ -164,8 +164,6 @@ ifeq ($(findstring -static,${LDFLAGS}),-static)
 endif
 FEATURE_CHECK_CFLAGS-libdw := $(LIBDW_CFLAGS)
 FEATURE_CHECK_LDFLAGS-libdw := $(LIBDW_LDFLAGS) $(DWARFLIBS)
-FEATURE_CHECK_CFLAGS-libdw-dwarf-unwind := $(LIBDW_CFLAGS)
-FEATURE_CHECK_LDFLAGS-libdw-dwarf-unwind := $(LIBDW_LDFLAGS) $(DWARFLIBS)
 FEATURE_CHECK_CFLAGS-dwarf_getlocations := $(LIBDW_CFLAGS)
 FEATURE_CHECK_LDFLAGS-dwarf_getlocations := $(LIBDW_LDFLAGS) $(DWARFLIBS)
 FEATURE_CHECK_CFLAGS-dwarf_getcfi := $(LIBDW_CFLAGS)
@@ -467,12 +465,6 @@ else
       endif
     endif
   else
-    ifndef NO_LIBDW_DWARF_UNWIND
-      ifneq ($(feature-libdw-dwarf-unwind),1)
-        NO_LIBDW_DWARF_UNWIND := 1
-        $(warning No libdw DWARF unwind found, Please install elfutils-devel/libdw-dev >= 0.158 and/or set LIBDW_DIR)
-      endif
-    endif
     ifneq ($(feature-libdw), 1)
       ifndef NO_LIBDW
         $(warning No libdw.h found or old libdw.h found or elfutils is older than 0.138, disables dwarf support. Please install new elfutils-devel/libdw-dev)