perf header: Add die information in CPU topology

With the new CPUID.1F, a new level type of CPU topology, 'die', is
introduced. The 'die' information in CPU topology should be added in
perf header.

To be compatible with old perf.data, the patch checks the section size
before reading the die information. The new info is added at the end of
the cpu_topology section, the old perf tool ignores the extra data.  It
never reads data crossing the section boundary.

The new perf tool with the patch can be used on legacy kernel. Add a new
function has_die_topology() to check if die topology information is
supported by kernel. The function only check X86 and CPU 0. Assuming
other CPUs have same topology.

Use similar method for core and socket to support die id and sibling
dies string.

Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Reviewed-by: Jiri Olsa <jolsa@kernel.org>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1559688644-106558-2-git-send-email-kan.liang@linux.intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/cputopo.c

@@ -1,5 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0
 #include <sys/param.h>
+#include <sys/utsname.h>
 #include <inttypes.h>
 #include <api/fs/fs.h>
 
@@ -8,9 +9,10 @@
 #include "util.h"
 #include "env.h"
 
-
 #define CORE_SIB_FMT \
 	"%s/devices/system/cpu/cpu%d/topology/core_siblings_list"
+#define DIE_SIB_FMT \
+	"%s/devices/system/cpu/cpu%d/topology/die_cpus_list"
 #define THRD_SIB_FMT \
 	"%s/devices/system/cpu/cpu%d/topology/thread_siblings_list"
 #define NODE_ONLINE_FMT \
@@ -34,12 +36,12 @@ static int build_cpu_topology(struct cpu_topology *tp, int cpu)
 		  sysfs__mountpoint(), cpu);
 	fp = fopen(filename, "r");
 	if (!fp)
-		goto try_threads;
+		goto try_dies;
 
 	sret = getline(&buf, &len, fp);
 	fclose(fp);
 	if (sret <= 0)
-		goto try_threads;
+		goto try_dies;
 
 	p = strchr(buf, '\n');
 	if (p)
@@ -57,6 +59,37 @@ static int build_cpu_topology(struct cpu_topology *tp, int cpu)
 	}
 	ret = 0;
 
+try_dies:
+	if (!tp->die_siblings)
+		goto try_threads;
+
+	scnprintf(filename, MAXPATHLEN, DIE_SIB_FMT,
+		  sysfs__mountpoint(), cpu);
+	fp = fopen(filename, "r");
+	if (!fp)
+		goto try_threads;
+
+	sret = getline(&buf, &len, fp);
+	fclose(fp);
+	if (sret <= 0)
+		goto try_threads;
+
+	p = strchr(buf, '\n');
+	if (p)
+		*p = '\0';
+
+	for (i = 0; i < tp->die_sib; i++) {
+		if (!strcmp(buf, tp->die_siblings[i]))
+			break;
+	}
+	if (i == tp->die_sib) {
+		tp->die_siblings[i] = buf;
+		tp->die_sib++;
+		buf = NULL;
+		len = 0;
+	}
+	ret = 0;
+
 try_threads:
 	scnprintf(filename, MAXPATHLEN, THRD_SIB_FMT,
 		  sysfs__mountpoint(), cpu);
@@ -98,21 +131,46 @@ void cpu_topology__delete(struct cpu_topology *tp)
 	for (i = 0 ; i < tp->core_sib; i++)
 		zfree(&tp->core_siblings[i]);
 
+	if (tp->die_sib) {
+		for (i = 0 ; i < tp->die_sib; i++)
+			zfree(&tp->die_siblings[i]);
+	}
+
 	for (i = 0 ; i < tp->thread_sib; i++)
 		zfree(&tp->thread_siblings[i]);
 
 	free(tp);
 }
 
+static bool has_die_topology(void)
+{
+	char filename[MAXPATHLEN];
+	struct utsname uts;
+
+	if (uname(&uts) < 0)
+		return false;
+
+	if (strncmp(uts.machine, "x86_64", 6))
+		return false;
+
+	scnprintf(filename, MAXPATHLEN, DIE_SIB_FMT,
+		  sysfs__mountpoint(), 0);
+	if (access(filename, F_OK) == -1)
+		return false;
+
+	return true;
+}
+
 struct cpu_topology *cpu_topology__new(void)
 {
 	struct cpu_topology *tp = NULL;
 	void *addr;
-	u32 nr, i;
+	u32 nr, i, nr_addr;
 	size_t sz;
 	long ncpus;
 	int ret = -1;
 	struct cpu_map *map;
+	bool has_die = has_die_topology();
 
 	ncpus = cpu__max_present_cpu();
 
@@ -126,7 +184,11 @@ struct cpu_topology *cpu_topology__new(void)
 	nr = (u32)(ncpus & UINT_MAX);
 
 	sz = nr * sizeof(char *);
-	addr = calloc(1, sizeof(*tp) + 2 * sz);
+	if (has_die)
+		nr_addr = 3;
+	else
+		nr_addr = 2;
+	addr = calloc(1, sizeof(*tp) + nr_addr * sz);
 	if (!addr)
 		goto out_free;
 
@@ -134,6 +196,10 @@ struct cpu_topology *cpu_topology__new(void)
 	addr += sizeof(*tp);
 	tp->core_siblings = addr;
 	addr += sz;
+	if (has_die) {
+		tp->die_siblings = addr;
+		addr += sz;
+	}
 	tp->thread_siblings = addr;
 
 	for (i = 0; i < nr; i++) {