perf tools: Build programs to copy 32-bit compatibility

perf tools copy VDSO out of memory.  However, on 64-bit machines there
may be 32-bit compatibility VDOs also.  To copy those requires separate
32-bit executables.

This patch adds to the build additional programs perf-read-vdso32 and
perf-read-vdsox32 for 32-bit and x32 respectively.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>,
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1414061124-26830-15-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
diff --git a/tools/perf/config/Makefile b/tools/perf/config/Makefile
index 58f6091..3ba2382 100644
--- a/tools/perf/config/Makefile
+++ b/tools/perf/config/Makefile
@@ -230,7 +230,9 @@
 	bionic				\
 	liberty				\
 	liberty-z			\
-	cplus-demangle
+	cplus-demangle			\
+	compile-32			\
+	compile-x32
 
 # Set FEATURE_CHECK_(C|LD)FLAGS-all for all CORE_FEATURE_TESTS features.
 # If in the future we need per-feature checks/flags for features not
@@ -622,6 +624,27 @@
     CFLAGS += -DHAVE_KVM_STAT_SUPPORT
 endif
 
+ifeq (${IS_64_BIT}, 1)
+  ifndef NO_PERF_READ_VDSO32
+    $(call feature_check,compile-32)
+    ifneq ($(feature-compile-32), 1)
+      NO_PERF_READ_VDSO32 := 1
+    endif
+  endif
+  ifneq (${IS_X86_64}, 1)
+    NO_PERF_READ_VDSOX32 := 1
+  endif
+  ifndef NO_PERF_READ_VDSOX32
+    $(call feature_check,compile-x32)
+    ifneq ($(feature-compile-x32), 1)
+      NO_PERF_READ_VDSOX32 := 1
+    endif
+  endif
+else
+  NO_PERF_READ_VDSO32 := 1
+  NO_PERF_READ_VDSOX32 := 1
+endif
+
 # Among the variables below, these:
 #   perfexecdir
 #   template_dir
diff --git a/tools/perf/config/Makefile.arch b/tools/perf/config/Makefile.arch
index 4b06719..851cd01 100644
--- a/tools/perf/config/Makefile.arch
+++ b/tools/perf/config/Makefile.arch
@@ -21,3 +21,11 @@
     RAW_ARCH := x86_64
   endif
 endif
+
+ifeq (${IS_X86_64}, 1)
+  IS_64_BIT := 1
+else ifeq ($(ARCH),x86)
+  IS_64_BIT := 0
+else
+  IS_64_BIT := $(shell echo __LP64__ | ${CC} ${CFLAGS} -E -x c - | tail -n 1)
+endif
diff --git a/tools/perf/config/feature-checks/Makefile b/tools/perf/config/feature-checks/Makefile
index 72ab298..7c68ec7 100644
--- a/tools/perf/config/feature-checks/Makefile
+++ b/tools/perf/config/feature-checks/Makefile
@@ -27,7 +27,9 @@
 	test-libunwind-debug-frame.bin	\
 	test-stackprotector-all.bin	\
 	test-timerfd.bin		\
-	test-libdw-dwarf-unwind.bin
+	test-libdw-dwarf-unwind.bin	\
+	test-compile-32.bin		\
+	test-compile-x32.bin
 
 CC := $(CROSS_COMPILE)gcc -MD
 PKG_CONFIG := $(CROSS_COMPILE)pkg-config
@@ -131,6 +133,12 @@
 test-sync-compare-and-swap.bin:
 	$(BUILD) -Werror
 
+test-compile-32.bin:
+	$(CC) -m32 -o $(OUTPUT)$@ test-compile.c
+
+test-compile-x32.bin:
+	$(CC) -mx32 -o $(OUTPUT)$@ test-compile.c
+
 -include *.d
 
 ###############################
diff --git a/tools/perf/config/feature-checks/test-compile.c b/tools/perf/config/feature-checks/test-compile.c
new file mode 100644
index 0000000..31dbf45
--- /dev/null
+++ b/tools/perf/config/feature-checks/test-compile.c
@@ -0,0 +1,4 @@
+int main(void)
+{
+	return 0;
+}