perf kvm: Add kvm-stat for loongarch64

Add support for 'perf kvm stat' on loongarch64 platform, now only kvm
exit event is supported.

Here is example output about "perf kvm --host stat report" command

   Event name   Samples   Sample%     Time (ns)   Time%   Mean Time (ns)
    Mem Store     83969    51.00%     625697070   8.00%             7451
     Mem Read     37641    22.00%     112485730   1.00%             2988
    Interrupt     15542     9.00%      20620190   0.00%             1326
        IOCSR     15207     9.00%      94296190   1.00%             6200
    Hypercall      4873     2.00%      12265280   0.00%             2516
         Idle      3713     2.00%    6322055860  87.00%          1702681
          FPU      1819     1.00%       2750300   0.00%             1511
   Inst Fetch       502     0.00%       1341740   0.00%             2672
   Mem Modify       324     0.00%        602240   0.00%             1858
       CPUCFG        55     0.00%         77610   0.00%             1411
          CSR        12     0.00%         19690   0.00%             1640
         LASX         3     0.00%          4870   0.00%             1623
          LSX         2     0.00%          2100   0.00%             1050

Signed-off-by: Bibo Mao <maobibo@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

1 files changed, 96 insertions, 0 deletions

diff --git a/tools/perf/arch/loongarch/util/header.c b/tools/perf/arch/loongarch/util/header.c
new file mode 100644
index 000000000000..d962dff55512
--- /dev/null
+++ b/tools/perf/arch/loongarch/util/header.c
@@ -0,0 +1,96 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Implementation of get_cpuid().
+ *
+ * Author: Nikita Shubin <n.shubin@yadro.com>
+ *         Bibo Mao <maobibo@loongson.cn>
+ *         Huacai Chen <chenhuacai@loongson.cn>
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <api/fs/fs.h>
+#include <errno.h>
+#include "util/debug.h"
+#include "util/header.h"
+
+/*
+ * Output example from /proc/cpuinfo
+ *   CPU Family              : Loongson-64bit
+ *   Model Name              : Loongson-3C5000
+ *   CPU Revision            : 0x10
+ *   FPU Revision            : 0x01
+ */
+#define CPUINFO_MODEL	"Model Name"
+#define CPUINFO		"/proc/cpuinfo"
+
+static char *_get_field(const char *line)
+{
+	char *line2, *nl;
+
+	line2 = strrchr(line, ' ');
+	if (!line2)
+		return NULL;
+
+	line2++;
+	nl = strrchr(line, '\n');
+	if (!nl)
+		return NULL;
+
+	return strndup(line2, nl - line2);
+}
+
+static char *_get_cpuid(void)
+{
+	unsigned long line_sz;
+	char *line, *model, *cpuid;
+	FILE *file;
+
+	file = fopen(CPUINFO, "r");
+	if (file == NULL)
+		return NULL;
+
+	line = model = cpuid = NULL;
+	while (getline(&line, &line_sz, file) != -1) {
+		if (strncmp(line, CPUINFO_MODEL, strlen(CPUINFO_MODEL)))
+			continue;
+
+		model = _get_field(line);
+		if (!model)
+			goto out_free;
+		break;
+	}
+
+	if (model && (asprintf(&cpuid, "%s", model) < 0))
+		cpuid = NULL;
+
+out_free:
+	fclose(file);
+	free(model);
+	return cpuid;
+}
+
+int get_cpuid(char *buffer, size_t sz)
+{
+	int ret = 0;
+	char *cpuid = _get_cpuid();
+
+	if (!cpuid)
+		return EINVAL;
+
+	if (sz < strlen(cpuid)) {
+		ret = ENOBUFS;
+		goto out_free;
+	}
+
+	scnprintf(buffer, sz, "%s", cpuid);
+
+out_free:
+	free(cpuid);
+	return ret;
+}
+
+char *get_cpuid_str(struct perf_pmu *pmu __maybe_unused)
+{
+	return _get_cpuid();
+}