perf tools: Propagate get_cpuid() error

For consistency, propagate the exact cause for get_cpuid() to have
failed.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/n/tip-9ig269f7ktnhh99g4l15vpu2@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/arch/powerpc/util/header.c

@@ -1,5 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0
 #include <sys/types.h>
+#include <errno.h>
 #include <unistd.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -30,7 +31,7 @@ get_cpuid(char *buffer, size_t sz)
 		buffer[nb-1] = '\0';
 		return 0;
 	}
-	return -1;
+	return ENOBUFS;
 }
 
 char *

tools/perf/arch/s390/util/header.c

@@ -8,6 +8,7 @@
  */
 
 #include <sys/types.h>
+#include <errno.h>
 #include <unistd.h>
 #include <stdio.h>
 #include <string.h>
@@ -54,7 +55,7 @@ int get_cpuid(char *buffer, size_t sz)
 
 	sysinfo = fopen(SYSINFO, "r");
 	if (sysinfo == NULL)
-		return -1;
+		return errno;
 
 	while ((read = getline(&line, &line_sz, sysinfo)) != -1) {
 		if (!strncmp(line, SYSINFO_MANU, strlen(SYSINFO_MANU))) {
@@ -89,7 +90,7 @@ int get_cpuid(char *buffer, size_t sz)
 
 	/* Missing manufacturer, type or model information should not happen */
 	if (!manufacturer[0] || !type[0] || !model[0])
-		return -1;
+		return EINVAL;
 
 	/*
 	 * Scan /proc/service_levels and return the CPU-MF counter facility
@@ -133,14 +134,14 @@ skip_sysinfo:
 	else
 		nbytes = snprintf(buffer, sz, "%s,%s,%s", manufacturer, type,
 				  model);
-	return (nbytes >= sz) ? -1 : 0;
+	return (nbytes >= sz) ? ENOBUFS : 0;
 }
 
 char *get_cpuid_str(struct perf_pmu *pmu __maybe_unused)
 {
 	char *buf = malloc(128);
 
-	if (buf && get_cpuid(buf, 128) < 0)
+	if (buf && get_cpuid(buf, 128))
 		zfree(&buf);
 	return buf;
 }

tools/perf/arch/x86/util/header.c

@@ -1,5 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0
 #include <sys/types.h>
+#include <errno.h>
 #include <unistd.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -58,7 +59,7 @@ __get_cpuid(char *buffer, size_t sz, const char *fmt)
 		buffer[nb-1] = '\0';
 		return 0;
 	}
-	return -1;
+	return ENOBUFS;
 }
 
 int

tools/perf/builtin-kvm.c

@@ -705,14 +705,15 @@ static int process_sample_event(struct perf_tool *tool,
 
 static int cpu_isa_config(struct perf_kvm_stat *kvm)
 {
-	char buf[64], *cpuid;
+	char buf[128], *cpuid;
 	int err;
 
 	if (kvm->live) {
 		err = get_cpuid(buf, sizeof(buf));
 		if (err != 0) {
-			pr_err("Failed to look up CPU type\n");
-			return err;
+			pr_err("Failed to look up CPU type: %s\n",
+			       str_error_r(err, buf, sizeof(buf)));
+			return -err;
 		}
 		cpuid = buf;
 	} else