[POWERPC] PS3: Fix printing of os-area magic numbers

Fix a bug in the printing of the os-area magic numbers which assumed
that magic numbers were zero terminated strings.  The magic numbers
are represented in memory as integers.  If the os-area sections are
not initialized correctly they could contained random data that would
be printed to the display.  Also unify the handling of header and db
magic numbers and make both of type array of u8.
Signed-off-by: NGeoff Levand <geoffrey.levand@am.sony.com>
Signed-off-by: NPaul Mackerras <paulus@samba.org>

arch/powerpc/platforms/ps3/os-area.c

@@ -23,6 +23,7 @@
 #include <linux/workqueue.h>
 #include <linux/fs.h>
 #include <linux/syscalls.h>
+#include <linux/ctype.h>
 
 #include <asm/lmb.h>
 
@@ -37,6 +38,8 @@ enum os_area_ldr_format {
 	HEADER_LDR_FORMAT_GZIP = 1,
 };
 
+#define OS_AREA_HEADER_MAGIC_NUM "cell_ext_os_area"
+
 /**
  * struct os_area_header - os area header segment.
  * @magic_num: Always 'cell_ext_os_area'.
@@ -114,13 +117,11 @@ struct os_area_params {
 	u8 _reserved_5[8];
 };
 
-enum {
-	OS_AREA_DB_MAGIC_NUM = 0x2d64622dU,
-};
+#define OS_AREA_DB_MAGIC_NUM "-db-"
 
 /**
  * struct os_area_db - Shared flash memory database.
- * @magic_num: Always '-db-' = 0x2d64622d.
+ * @magic_num: Always '-db-'.
  * @version: os_area_db format version number.
  * @index_64: byte offset of the database id index for 64 bit variables.
  * @count_64: number of usable 64 bit index entries
@@ -135,7 +136,7 @@ enum {
  */
 
 struct os_area_db {
-	u32 magic_num;
+	u8 magic_num[4];
 	u16 version;
 	u16 _reserved_1;
 	u16 index_64;
@@ -265,12 +266,26 @@ static void __init os_area_get_property(struct device_node *node,
 			prop->name);
 }
 
+static void dump_field(char *s, const u8 *field, int size_of_field)
+{
+#if defined(DEBUG)
+	int i;
+
+	for (i = 0; i < size_of_field; i++)
+		s[i] = isprint(field[i]) ? field[i] : '.';
+	s[i] = 0;
+#endif
+}
+
 #define dump_header(_a) _dump_header(_a, __func__, __LINE__)
 static void _dump_header(const struct os_area_header *h, const char *func,
 	int line)
 {
+	char str[sizeof(h->magic_num) + 1];
+
+	dump_field(str, h->magic_num, sizeof(h->magic_num));
 	pr_debug("%s:%d: h.magic_num:       '%s'\n", func, line,
-		h->magic_num);
+		str);
 	pr_debug("%s:%d: h.hdr_version:     %u\n", func, line,
 		h->hdr_version);
 	pr_debug("%s:%d: h.db_area_offset:  %u\n", func, line,
@@ -311,7 +326,8 @@ static void _dump_params(const struct os_area_params *p, const char *func,
 
 static int verify_header(const struct os_area_header *header)
 {
-	if (memcmp(header->magic_num, "cell_ext_os_area", 16)) {
+	if (memcmp(header->magic_num, OS_AREA_HEADER_MAGIC_NUM,
+		sizeof(header->magic_num))) {
 		pr_debug("%s:%d magic_num failed\n", __func__, __LINE__);
 		return -1;
 	}
@@ -331,7 +347,8 @@ static int verify_header(const struct os_area_header *header)
 
 static int db_verify(const struct os_area_db *db)
 {
-	if (db->magic_num != OS_AREA_DB_MAGIC_NUM) {
+	if (memcmp(db->magic_num, OS_AREA_DB_MAGIC_NUM,
+		sizeof(db->magic_num))) {
 		pr_debug("%s:%d magic_num failed\n", __func__, __LINE__);
 		return -1;
 	}
@@ -484,8 +501,11 @@ static int db_get_rtc_diff(const struct os_area_db *db, int64_t *rtc_diff)
 static void _dump_db(const struct os_area_db *db, const char *func,
 	int line)
 {
+	char str[sizeof(db->magic_num) + 1];
+
+	dump_field(str, db->magic_num, sizeof(db->magic_num));
 	pr_debug("%s:%d: db.magic_num:      '%s'\n", func, line,
-		(const char*)&db->magic_num);
+		str);
 	pr_debug("%s:%d: db.version:         %u\n", func, line,
 		db->version);
 	pr_debug("%s:%d: db.index_64:        %u\n", func, line,
@@ -516,7 +536,7 @@ static void os_area_db_init(struct os_area_db *db)
 
 	memset(db, 0, sizeof(struct os_area_db));
 
-	db->magic_num = OS_AREA_DB_MAGIC_NUM;
+	memcpy(db->magic_num, OS_AREA_DB_MAGIC_NUM, sizeof(db->magic_num));
 	db->version = 1;
 	db->index_64 = HEADER_SIZE;
 	db->count_64 = VALUES_64_COUNT;