[PATCH 3/5] perf util: Introduce architecture specific errno/name mapping

[Hendrik Brueckner <brueckner@linux.vnet.ibm.com>]

Introduce a script that generates a mapping of errno numbers to
their names for each architecture that is supported by perf (i.e.
has a subdirectory in tools/perf/arch/).

The file is generated as util/errno-names.c.  A corresponding
header file util/errno-names.h is provided that defines the
arch_errno_to_name() function.  Use arch_errno_to_name() to
lookup an errno value to obtain the errno name (e.g. ENOENT)
for a particular architecture.

This is to be used by perf trace.

Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Reviewed-by: Thomas Richter <tmricht@linux.vnet.ibm.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
---
 tools/perf/.gitignore                   |   1 +
 tools/perf/Makefile.config              |   2 +-
 tools/perf/Makefile.perf                |   9 ++-
 tools/perf/util/Build                   |   1 +
 tools/perf/util/errno-names.h           |   7 +++
 tools/perf/util/generate-errno-names.sh | 101 ++++++++++++++++++++++++++++++++
 6 files changed, 118 insertions(+), 3 deletions(-)
 create mode 100644 tools/perf/util/errno-names.h
 create mode 100755 tools/perf/util/generate-errno-names.sh

diff --git a/tools/perf/.gitignore b/tools/perf/.gitignore
index 643cc4ba..1d4d43c 100644
--- a/tools/perf/.gitignore
+++ b/tools/perf/.gitignore
@@ -14,6 +14,7 @@ perf*.1
 perf*.xml
 perf*.html
 common-cmds.h
+errno-names.c
 perf.data
 perf.data.old
 output.svg
diff --git a/tools/perf/Makefile.config b/tools/perf/Makefile.config
index 12dec6e..90ce14f 100644
--- a/tools/perf/Makefile.config
+++ b/tools/perf/Makefile.config
@@ -249,7 +249,7 @@ INC_FLAGS += -I$(srctree)/tools/arch/$(SRCARCH)/include/uapi
 INC_FLAGS += -I$(srctree)/tools/arch/$(SRCARCH)/include/
 INC_FLAGS += -I$(srctree)/tools/arch/$(SRCARCH)/
 
-# $(obj-perf)      for generated common-cmds.h
+# $(obj-perf)      for generated common-cmds.h and errno-names.c
 # $(obj-perf)/util for generated bison/flex headers
 ifneq ($(OUTPUT),)
 INC_FLAGS += -I$(obj-perf)/util
diff --git a/tools/perf/Makefile.perf b/tools/perf/Makefile.perf
index 9fdefd7..332b4b4 100644
--- a/tools/perf/Makefile.perf
+++ b/tools/perf/Makefile.perf
@@ -518,6 +518,9 @@ $(OUTPUT)common-cmds.h: util/generate-cmdlist.sh command-list.txt
 $(OUTPUT)common-cmds.h: $(wildcard Documentation/perf-*.txt)
 	$(QUIET_GEN). util/generate-cmdlist.sh > $@+ && mv $@+ $@
 
+$(OUTPUT)util/errno-names.c: util/generate-errno-names.sh
+	$(QUIET_GEN). util/generate-errno-names.sh "$(CC)" "$(srctree)/tools" > $@+ && mv $@+ $@
+
 $(SCRIPTS) : % : %.sh
 	$(QUIET_GEN)$(INSTALL) '$@.sh' '$(OUTPUT)$@'
 
@@ -565,7 +568,8 @@ prepare: $(OUTPUT)PERF-VERSION-FILE $(OUTPUT)common-cmds.h archheaders $(drm_ioc
 	$(vhost_virtio_ioctl_array) \
 	$(madvise_behavior_array) \
 	$(perf_ioctl_array) \
-	$(prctl_option_array)
+	$(prctl_option_array) \
+	$(OUTPUT)util/errno-names.c
 
 $(OUTPUT)%.o: %.c prepare FORCE
 	$(Q)$(MAKE) -f $(srctree)/tools/build/Makefile.build dir=$(build-dir) $@
@@ -847,7 +851,8 @@ clean:: $(LIBTRACEEVENT)-clean $(LIBAPI)-clean $(LIBBPF)-clean $(LIBSUBCMD)-clea
 		$(OUTPUT)$(kcmp_type_array) \
 		$(OUTPUT)$(vhost_virtio_ioctl_array) \
 		$(OUTPUT)$(perf_ioctl_array) \
-		$(OUTPUT)$(prctl_option_array)
+		$(OUTPUT)$(prctl_option_array) \
+		$(OUTPUT)util/errno-names.c
 	$(QUIET_SUBDIR0)Documentation $(QUIET_SUBDIR1) clean
 
 #
diff --git a/tools/perf/util/Build b/tools/perf/util/Build
index 7c6a8b4..6d4f8f0 100644
--- a/tools/perf/util/Build
+++ b/tools/perf/util/Build
@@ -5,6 +5,7 @@ libperf-y += config.o
 libperf-y += ctype.o
 libperf-y += db-export.o
 libperf-y += env.o
+libperf-y += errno-names.o
 libperf-y += event.o
 libperf-y += evlist.o
 libperf-y += evsel.o
diff --git a/tools/perf/util/errno-names.h b/tools/perf/util/errno-names.h
new file mode 100644
index 0000000..1cdcbd3
--- /dev/null
+++ b/tools/perf/util/errno-names.h
@@ -0,0 +1,7 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __PERF_ERRNO_NAMES_H
+#define __PERF_ERRNO_NAMES_H
+
+const char *arch_errno_to_name(const char *arch, int err);
+
+#endif /* __PERF_ERRNO_NAMES_H */
diff --git a/tools/perf/util/generate-errno-names.sh b/tools/perf/util/generate-errno-names.sh
new file mode 100755
index 0000000..1738800
--- /dev/null
+++ b/tools/perf/util/generate-errno-names.sh
@@ -0,0 +1,101 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+#
+# Generate C file mapping errno codes to errno names.
+#
+# Copyright IBM Corp. 2018
+# Author(s):  Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
+
+gcc="$1"
+toolsdir="$2"
+include_path="-I$toolsdir/include/uapi"
+
+arch_string()
+{
+	echo "$1" |sed -e 'y/- /__/' |tr '[[:upper:]]' '[[:lower:]]'
+}
+
+asm_errno_file()
+{
+	local arch="$1"
+	local header
+
+	header="$toolsdir/arch/$arch/include/uapi/asm/errno.h"
+	if test -r "$header"; then
+		echo "$header"
+	else
+		echo "$toolsdir/include/uapi/asm-generic/errno.h"
+	fi
+}
+
+create_errno_lookup_func()
+{
+	local arch=$(arch_string "$1")
+	local nr name
+
+	cat <<EoFuncBegin
+static const char *errno_to_name__$arch(int err)
+{
+	switch (err) {
+EoFuncBegin
+
+	while read name nr; do
+		printf '\tcase %d: return "%s";\n' $nr $name
+	done
+
+	cat <<EoFuncEnd
+	default:
+		return "(unknown)";
+	}
+}
+
+EoFuncEnd
+}
+
+process_arch()
+{
+	local arch="$1"
+	local asm_errno=$(asm_errno_file "$arch")
+
+	$gcc $include_path -E -dM -x c $asm_errno \
+		|grep -hE '^#define[[:blank:]]+(E[^[:blank:]]+)[[:blank:]]+([[:digit:]]+).*' \
+		|awk '{ print $2","$3; }' \
+		|sort -t, -k2 -nu \
+		|IFS=, create_errno_lookup_func "$arch"
+}
+
+create_arch_errno_table_func()
+{
+	local archlist="$1"
+	local default="$2"
+	local arch
+
+	printf 'const char *arch_errno_to_name(const char *arch, int err)\n'
+	printf '{\n'
+	for arch in $archlist; do
+		printf '\tif (!strcmp(arch, "%s"))\n' $(arch_string "$arch")
+		printf '\t\treturn errno_to_name__%s(err);\n' $(arch_string "$arch")
+	done
+	printf '\treturn errno_to_name__%s(err);\n' $(arch_string "$default")
+	printf '}'
+}
+
+cat <<EoHEADER
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#include <string.h>
+#include "errno-names.h"
+
+EoHEADER
+
+# Create list of architectures and ignore those that do not appear
+# in tools/perf/arch
+archlist=""
+for arch in $(find $toolsdir/arch -maxdepth 1 -mindepth 1 -type d -printf "%f\n" |sort); do
+	test -d arch/$arch && archlist="$archlist $arch"
+done
+
+for arch in $archlist generic; do
+	process_arch "$arch"
+done
+create_arch_errno_table_func "$archlist" "generic"
-- 
1.8.3.1