[PATCH 2/9] perf arch: Make the default get_cpuid() return compatible error

[Arnaldo Carvalho de Melo]

From: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>

Some of the functions calling get_cpuid() propagate back the error it
returns, and all are using errno (positive) values, make the weak
default get_cpuid() function return ENOSYS to be consistent and to allow
checking if this is an arch not providing this function or if a provided
one is having trouble getting the cpuid, to decide if the warning should
be provided to the user or just a debug message should be emitted.

Reviewed-by: Mark Rutland <mark.rutland@xxxxxxx>
Tested-by: Mark Rutland <mark.rutland@xxxxxxx>
Tested-by: John Garry <john.garry@xxxxxxxxxx> # arm64
Acked-by: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Will Deacon <will@xxxxxxxxxx>
Link: https://lkml.kernel.org/n/tip-lxwjr0cd2eggzx04a780ffrv@xxxxxxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
 tools/perf/util/header.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
index becc2d109423..4d39a75551a0 100644
--- a/tools/perf/util/header.c
+++ b/tools/perf/util/header.c
@@ -850,7 +850,7 @@ int __weak strcmp_cpuid_str(const char *mapcpuid, const char *cpuid)
  */
 int __weak get_cpuid(char *buffer __maybe_unused, size_t sz __maybe_unused)
 {
-	return -1;
+	return ENOSYS; /* Not implemented */
 }
 
 static int write_cpuid(struct feat_fd *ff,
-- 
2.21.0