perf util: Remove kernel version deadcode

fetch_kernel_version() has been unused since Ian's 2023 commit
3d6dfae ("perf parse-events: Remove BPF event support")

Remove it, and it's helpers.

I noticed there are a bunch of kernel-version macros that are also
unused nearby.

Also remove them.

Reviewed-by: Ian Rogers <irogers@google.com>
Signed-off-by: Dr. David Alan Gilbert <linux@treblig.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20241116155850.113129-1-linux@treblig.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Author: Dr. David Alan Gilbert

tools/perf/util/util.c

@@ -342,91 +342,6 @@ bool perf_event_paranoid_check(int max_level)
 	return perf_event_paranoid() <= max_level;
 }
 
-static int
-fetch_ubuntu_kernel_version(unsigned int *puint)
-{
-	ssize_t len;
-	size_t line_len = 0;
-	char *ptr, *line = NULL;
-	int version, patchlevel, sublevel, err;
-	FILE *vsig;
-
-	if (!puint)
-		return 0;
-
-	vsig = fopen("/proc/version_signature", "r");
-	if (!vsig) {
-		pr_debug("Open /proc/version_signature failed: %s\n",
-			 strerror(errno));
-		return -1;
-	}
-
-	len = getline(&line, &line_len, vsig);
-	fclose(vsig);
-	err = -1;
-	if (len <= 0) {
-		pr_debug("Reading from /proc/version_signature failed: %s\n",
-			 strerror(errno));
-		goto errout;
-	}
-
-	ptr = strrchr(line, ' ');
-	if (!ptr) {
-		pr_debug("Parsing /proc/version_signature failed: %s\n", line);
-		goto errout;
-	}
-
-	err = sscanf(ptr + 1, "%d.%d.%d",
-		     &version, &patchlevel, &sublevel);
-	if (err != 3) {
-		pr_debug("Unable to get kernel version from /proc/version_signature '%s'\n",
-			 line);
-		goto errout;
-	}
-
-	*puint = (version << 16) + (patchlevel << 8) + sublevel;
-	err = 0;
-errout:
-	free(line);
-	return err;
-}
-
-int
-fetch_kernel_version(unsigned int *puint, char *str,
-		     size_t str_size)
-{
-	struct utsname utsname;
-	int version, patchlevel, sublevel, err;
-	bool int_ver_ready = false;
-
-	if (access("/proc/version_signature", R_OK) == 0)
-		if (!fetch_ubuntu_kernel_version(puint))
-			int_ver_ready = true;
-
-	if (uname(&utsname))
-		return -1;
-
-	if (str && str_size) {
-		strncpy(str, utsname.release, str_size);
-		str[str_size - 1] = '\0';
-	}
-
-	if (!puint || int_ver_ready)
-		return 0;
-
-	err = sscanf(utsname.release, "%d.%d.%d",
-		     &version, &patchlevel, &sublevel);
-
-	if (err != 3) {
-		pr_debug("Unable to get kernel version from uname '%s'\n",
-			 utsname.release);
-		return -1;
-	}
-
-	*puint = (version << 16) + (patchlevel << 8) + sublevel;
-	return 0;
-}
-
 int perf_tip(char **strp, const char *dirpath)
 {
 	struct strlist *tips;

tools/perf/util/util.h

@@ -46,14 +46,6 @@ int sysctl__max_stack(void);
 
 bool sysctl__nmi_watchdog_enabled(void);
 
-int fetch_kernel_version(unsigned int *puint,
-			 char *str, size_t str_sz);
-#define KVER_VERSION(x)		(((x) >> 16) & 0xff)
-#define KVER_PATCHLEVEL(x)	(((x) >> 8) & 0xff)
-#define KVER_SUBLEVEL(x)	((x) & 0xff)
-#define KVER_FMT	"%d.%d.%d"
-#define KVER_PARAM(x)	KVER_VERSION(x), KVER_PATCHLEVEL(x), KVER_SUBLEVEL(x)
-
 int perf_tip(char **strp, const char *dirpath);
 
 #ifndef HAVE_SCHED_GETCPU_SUPPORT