[Qemu-arm] [RFC PATCH v2 2/3] utils: Add cpuinfo helper to fetch /proc/cpuinfo

[vijayak]

From: Vijaya Kumar K <address@hidden>

utils cannot read target cpu information to
fetch cpu information to implement cpu specific
features or erratas. For this parse /proc/cpuinfo
and fetch cpu information.

For now this helper only fetches cpu information
for arm architectures.

Signed-off-by: Vijaya Kumar K <address@hidden>
Signed-off-by: Suresh <address@hidden>
---
 include/qemu-common.h |   11 ++++++
 util/Makefile.objs    |    1 +
 util/cpuinfo.c        |   94 +++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 106 insertions(+)

diff --git a/include/qemu-common.h b/include/qemu-common.h
index 163bcbb..364aa0a 100644
--- a/include/qemu-common.h
+++ b/include/qemu-common.h
@@ -170,4 +170,15 @@ void page_size_init(void);
  * returned. */
 bool dump_in_progress(void);
 
+/*
+ * cpu info structure read from /proc/cpuinfo
+ */
+
+struct cpu_info {
+    uint32_t imp;
+    uint32_t arch;
+    uint32_t part;
+};
+
+void qemu_read_cpu_info(struct cpu_info *cinf);
 #endif
diff --git a/util/Makefile.objs b/util/Makefile.objs
index a8a777e..59cde64 100644
--- a/util/Makefile.objs
+++ b/util/Makefile.objs
@@ -32,3 +32,4 @@ util-obj-y += buffer.o
 util-obj-y += timed-average.o
 util-obj-y += base64.o
 util-obj-y += log.o
+util-obj-y += cpuinfo.o
diff --git a/util/cpuinfo.c b/util/cpuinfo.c
new file mode 100644
index 0000000..e049672
--- /dev/null
+++ b/util/cpuinfo.c
@@ -0,0 +1,94 @@
+/*
+ * Dealing with /proc/cpuinfo
+ *
+ * Copyright (C) 2016 Cavium, Inc.
+ *
+ * Authors:
+ *  Vijaya Kumar K <address@hidden>
+ *
+ * This work is licensed under the terms of the GNU LGPL, version 2.1
+ * or later.  See the COPYING.LIB file in the top-level directory.
+ */
+
+#include "qemu/osdep.h"
+#include "qemu-common.h"
+#include <string.h>
+
+#if defined(__arm__) || defined(__aarch64__)
+static uint32_t read_arm_cpu_implementer(char *str)
+{
+    char *match;
+    uint32_t imp = 0;
+
+    match = strstr(str, "CPU implementer");
+    if (match != NULL) {
+        sscanf(match, "CPU implementer : 0x%x", &imp);
+    }
+
+    return imp;
+}
+
+static uint32_t read_arm_cpu_architecture(char *str)
+{
+    char *match;
+    uint32_t arch = 0;
+
+    match = strstr(str, "CPU architecture");
+    if (match != NULL) {
+        sscanf(match, "CPU architecture: %d", &arch);
+    }
+
+    return arch;
+}
+
+static uint32_t read_arm_cpu_part(char *str)
+{
+    char *match;
+    uint32_t part = 0;
+
+    match = strstr(str, "CPU part");
+    if (match != NULL) {
+        sscanf(match, "CPU part : 0x%x", &part);
+    }
+
+    return part;
+}
+#endif
+
+void qemu_read_cpu_info(struct cpu_info *cinf)
+{
+    FILE *fp;
+    char *buf;
+#define BUF_SIZE 1024
+    size_t bytes_read;
+
+    cinf->imp = cinf->arch = cinf->part = 0;
+    fp = fopen("/proc/cpuinfo", "r");
+    if (!fp) {
+        return;
+    }
+
+    buf = g_malloc0(BUF_SIZE);
+    if (!buf) {
+        fclose(fp);
+        return;
+    }
+
+    /* Read the contents of /proc/cpuinfo into the buffer. */
+    bytes_read = fread(buf, 1, BUF_SIZE, fp);
+    fclose(fp);
+
+    if (bytes_read == 0) {
+        g_free(buf);
+        return;
+    }
+
+    buf[bytes_read] = '\0';
+
+#if defined(__arm__) || defined(__aarch64__)
+    cinf->imp = read_arm_cpu_implementer(buf);
+    cinf->arch = read_arm_cpu_architecture(buf);
+    cinf->part = read_arm_cpu_part(buf);
+#endif
+    g_free(buf);
+}
-- 
1.7.9.5