perf env: Adopt perf_env__arch() from the annotate code

And use it in the libunwind case, with both passing a valid perf_env to
extract the arch to be normalized from and passing NULL with the same
semantic as in the annotate code: to get it from uname() uts.machine.

Now the code to generate per arch errno translation tables (int/string)
can use it to decode perf.data files recorded in a different arch than
that where 'perf trace' (or any other analysis tool) runs.

Cc: Adrian Hunter <[e-mail]>
Cc: David Ahern <[e-mail]>
Cc: Hendrik Brueckner <[e-mail]>
Cc: Jiri Olsa <[e-mail]>
Cc: Michael Petlan <[e-mail]>
Cc: Namhyung Kim <[e-mail]>
Cc: Thomas Richter <[e-mail]>
Cc: Wang Nan <[e-mail]>
Link: https://lkml.kernel.org/n/[e-mail]
Signed-off-by: Arnaldo Carvalho de Melo <[e-mail]>

tools/perf/arch/common.c

···
 // SPDX-License-Identifier: GPL-2.0
 #include <stdio.h>
-#include <sys/utsname.h>
 #include "common.h"
+#include "../util/env.h"
 #include "../util/util.h"
 #include "../util/debug.h"
-
-#include "sane_ctype.h"
 
 const char *const arm_triplets[] = {
 	"arm-eabi-",
···
 	return -1;
 }
 
-/*
- * Return architecture name in a normalized form.
- * The conversion logic comes from the Makefile.
- */
-const char *normalize_arch(char *arch)
-{
-	if (!strcmp(arch, "x86_64"))
-		return "x86";
-	if (arch[0] == 'i' && arch[2] == '8' && arch[3] == '6')
-		return "x86";
-	if (!strcmp(arch, "sun4u") || !strncmp(arch, "sparc", 5))
-		return "sparc";
-	if (!strcmp(arch, "aarch64") || !strcmp(arch, "arm64"))
-		return "arm64";
-	if (!strncmp(arch, "arm", 3) || !strcmp(arch, "sa110"))
-		return "arm";
-	if (!strncmp(arch, "s390", 4))
-		return "s390";
-	if (!strncmp(arch, "parisc", 6))
-		return "parisc";
-	if (!strncmp(arch, "powerpc", 7) || !strncmp(arch, "ppc", 3))
-		return "powerpc";
-	if (!strncmp(arch, "mips", 4))
-		return "mips";
-	if (!strncmp(arch, "sh", 2) && isdigit(arch[2]))
-		return "sh";
-
-	return arch;
-}
-
 static int perf_env__lookup_binutils_path(struct perf_env *env,
 					  const char *name, const char **path)
 {
 	int idx;
-	const char *arch, *cross_env;
-	struct utsname uts;
+	const char *arch = perf_env__arch(env), *cross_env;
 	const char *const *path_list;
 	char *buf = NULL;
-
-	arch = normalize_arch(env->arch);
-
-	if (uname(&uts) < 0)
-		goto out;
 
 	/*
 	 * We don't need to try to find objdump path for native system.
 	 * Just use default binutils path (e.g.: "objdump").
 	 */
-	if (!strcmp(normalize_arch(uts.machine), arch))
+	if (!strcmp(perf_env__arch(NULL), arch))
 		goto out;
 
 	cross_env = getenv("CROSS_COMPILE");

tools/perf/arch/common.h

···
 extern const char *objdump_path;
 
 int perf_env__lookup_objdump(struct perf_env *env);
-const char *normalize_arch(char *arch);
 
 #endif /* ARCH_PERF_COMMON_H */

tools/perf/util/annotate.c

···
 #include <pthread.h>
 #include <linux/bitops.h>
 #include <linux/kernel.h>
-#include <sys/utsname.h>
 
 #include "sane_ctype.h"
 
···
 
 	free(build_id_path);
 	return 0;
-}
-
-static const char *perf_env__arch(struct perf_env *env)
-{
-	struct utsname uts;
-	char *arch_name;
-
-	if (!env) { /* Assume local operation */
-		if (uname(&uts) < 0)
-			return NULL;
-		arch_name = uts.machine;
-	} else
-		arch_name = env->arch;
-
-	return normalize_arch(arch_name);
 }
 
 static int symbol__disassemble(struct symbol *sym, struct annotate_args *args)

tools/perf/util/env.c

···
 // SPDX-License-Identifier: GPL-2.0
 #include "cpumap.h"
 #include "env.h"
+#include "sane_ctype.h"
 #include "util.h"
 #include <errno.h>
+#include <sys/utsname.h>
 
 struct perf_env perf_env;
 
···
 	free(cache->type);
 	free(cache->map);
 	free(cache->size);
+}
+
+/*
+ * Return architecture name in a normalized form.
+ * The conversion logic comes from the Makefile.
+ */
+static const char *normalize_arch(char *arch)
+{
+	if (!strcmp(arch, "x86_64"))
+		return "x86";
+	if (arch[0] == 'i' && arch[2] == '8' && arch[3] == '6')
+		return "x86";
+	if (!strcmp(arch, "sun4u") || !strncmp(arch, "sparc", 5))
+		return "sparc";
+	if (!strcmp(arch, "aarch64") || !strcmp(arch, "arm64"))
+		return "arm64";
+	if (!strncmp(arch, "arm", 3) || !strcmp(arch, "sa110"))
+		return "arm";
+	if (!strncmp(arch, "s390", 4))
+		return "s390";
+	if (!strncmp(arch, "parisc", 6))
+		return "parisc";
+	if (!strncmp(arch, "powerpc", 7) || !strncmp(arch, "ppc", 3))
+		return "powerpc";
+	if (!strncmp(arch, "mips", 4))
+		return "mips";
+	if (!strncmp(arch, "sh", 2) && isdigit(arch[2]))
+		return "sh";
+
+	return arch;
+}
+
+const char *perf_env__arch(struct perf_env *env)
+{
+	struct utsname uts;
+	char *arch_name;
+
+	if (!env) { /* Assume local operation */
+		if (uname(&uts) < 0)
+			return NULL;
+		arch_name = uts.machine;
+	} else
+		arch_name = env->arch;
+
+	return normalize_arch(arch_name);
 }

tools/perf/util/env.h

···
 int perf_env__read_cpu_topology_map(struct perf_env *env);
 
 void cpu_cache_level__free(struct cpu_cache_level *cache);
+
+const char *perf_env__arch(struct perf_env *env);
 #endif /* __PERF_ENV_H */

tools/perf/util/unwind-libunwind.c

···
 #include "thread.h"
 #include "session.h"
 #include "debug.h"
-#include "arch/common.h"
+#include "env.h"
 
 struct unwind_libunwind_ops __weak *local_unwind_libunwind_ops;
 struct unwind_libunwind_ops __weak *x86_32_unwind_libunwind_ops;
···
 	if (dso_type == DSO__TYPE_UNKNOWN)
 		return 0;
 
-	arch = normalize_arch(thread->mg->machine->env->arch);
+	arch = perf_env__arch(thread->mg->machine->env);
 
 	if (!strcmp(arch, "x86")) {
 		if (dso_type != DSO__TYPE_64BIT)