[IA64] use snprintf() on features field of /proc/cpuinfo

Some patches have turned up on xen-devel recently to convert strcpy()
to safer alternatives and so forth.  While reviewing those patches
I noticed that the features string building could be cleaned up.

This patch uses snprintf() instead of strcpy() and direct character
pointer manipulation.  It makes the features string building safe and
gets rid of the special case for features output in show_cpuinfo()

Additionally I removed the (int) cast of ARRAY_SIZE, which seems to
serve no purpose.

Signed-off-by: Aron Griffis <aron@hp.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>

arch/ia64/kernel/setup.c

@@ -569,34 +569,31 @@ show_cpuinfo (struct seq_file *m, void *v)
 		{ 1UL << 1, "spontaneous deferral"},
 		{ 1UL << 2, "16-byte atomic ops" }
 	};
-	char features[128], *cp, sep;
+	char features[128], *cp, *sep;
 	struct cpuinfo_ia64 *c = v;
 	unsigned long mask;
 	unsigned long proc_freq;
-	int i;
+	int i, size;
 
 	mask = c->features;
 
 	/* build the feature string: */
-	memcpy(features, " standard", 10);
+	memcpy(features, "standard", 9);
 	cp = features;
-	sep = 0;
-	for (i = 0; i < (int) ARRAY_SIZE(feature_bits); ++i) {
+	size = sizeof(features);
+	sep = "";
+	for (i = 0; i < ARRAY_SIZE(feature_bits) && size > 1; ++i) {
 		if (mask & feature_bits[i].mask) {
-			if (sep)
-				*cp++ = sep;
-			sep = ',';
-			*cp++ = ' ';
-			strcpy(cp, feature_bits[i].feature_name);
-			cp += strlen(feature_bits[i].feature_name);
+			cp += snprintf(cp, size, "%s%s", sep,
+				       feature_bits[i].feature_name),
+			sep = ", ";
 			mask &= ~feature_bits[i].mask;
+			size = sizeof(features) - (cp - features);
 		}
 	}
-	if (mask) {
-		/* print unknown features as a hex value: */
-		if (sep)
-			*cp++ = sep;
-		sprintf(cp, " 0x%lx", mask);
+	if (mask && size > 1) {
+		/* print unknown features as a hex value */
+		snprintf(cp, size, "%s0x%lx", sep, mask);
 	}
 
 	proc_freq = cpufreq_quick_get(cpunum);
@@ -612,7 +609,7 @@ show_cpuinfo (struct seq_file *m, void *v)
 		   "model name : %s\n"
 		   "revision   : %u\n"
 		   "archrev    : %u\n"
-		   "features   :%s\n"	/* don't change this---it _is_ right! */
+		   "features   : %s\n"
 		   "cpu number : %lu\n"
 		   "cpu regs   : %u\n"
 		   "cpu MHz    : %lu.%06lu\n"