s390/sysinfo,stsi: change return code handling

Change return code handling of the stsi() function:

In case function code 0 was specified the return value is the
current configuration level (already shifted). That way all
the code that actually copied the stsi_0() function can go
away.

Otherwise the return value is 0 (success) or negative to
indicate an error (currently only -EOPNOTSUPP).

Also stsi() is no longer an inline function. The function is
not performance critical, but every caller would generate an
exception table entry for this function.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

3 files changed, 45 insertions, 33 deletions

diff --git a/arch/s390/kernel/early.c b/arch/s390/kernel/early.c
index e8000d5ff533..7f4717675c19 100644
--- a/arch/s390/kernel/early.c
+++ b/arch/s390/kernel/early.c
@@ -222,12 +222,12 @@ static noinline __init void detect_machine_type(void)
 	struct sysinfo_3_2_2 *vmms = (struct sysinfo_3_2_2 *)&sysinfo_page;
 
 	/* Check current-configuration-level */
-	if ((stsi(NULL, 0, 0, 0) >> 28) <= 2) {
+	if (stsi(NULL, 0, 0, 0) <= 2) {
 		S390_lowcore.machine_flags |= MACHINE_FLAG_LPAR;
 		return;
 	}
 	/* Get virtual-machine cpu information. */
-	if (stsi(vmms, 3, 2, 2) == -ENOSYS || !vmms->count)
+	if (stsi(vmms, 3, 2, 2) || !vmms->count)
 		return;
 
 	/* Running under KVM? If not we assume z/VM */
@@ -246,7 +246,7 @@ static __init void setup_topology(void)
 		return;
 	S390_lowcore.machine_flags |= MACHINE_FLAG_TOPOLOGY;
 	for (max_mnest = 6; max_mnest > 1; max_mnest--) {
-		if (stsi(&sysinfo_page, 15, 1, max_mnest) != -ENOSYS)
+		if (stsi(&sysinfo_page, 15, 1, max_mnest) == 0)
 			break;
 	}
 	topology_max_mnest = max_mnest;
diff --git a/arch/s390/kernel/lgr.c b/arch/s390/kernel/lgr.c
index eca94e74d19a..6ea6d69339b5 100644
--- a/arch/s390/kernel/lgr.c
+++ b/arch/s390/kernel/lgr.c
@@ -51,16 +51,6 @@ static struct lgr_info lgr_info_cur;
 static struct debug_info *lgr_dbf;
 
 /*
- * Return number of valid stsi levels
- */
-static inline int stsi_0(void)
-{
-	int rc = stsi(NULL, 0, 0, 0);
-
-	return rc == -ENOSYS ? rc : (((unsigned int) rc) >> 28);
-}
-
-/*
  * Copy buffer and then convert it to ASCII
  */
 static void cpascii(char *dst, char *src, int size)
@@ -76,7 +66,7 @@ static void lgr_stsi_1_1_1(struct lgr_info *lgr_info)
 {
 	struct sysinfo_1_1_1 *si = (void *) lgr_page;
 
-	if (stsi(si, 1, 1, 1) == -ENOSYS)
+	if (stsi(si, 1, 1, 1))
 		return;
 	cpascii(lgr_info->manufacturer, si->manufacturer,
 		sizeof(si->manufacturer));
@@ -93,7 +83,7 @@ static void lgr_stsi_2_2_2(struct lgr_info *lgr_info)
 {
 	struct sysinfo_2_2_2 *si = (void *) lgr_page;
 
-	if (stsi(si, 2, 2, 2) == -ENOSYS)
+	if (stsi(si, 2, 2, 2))
 		return;
 	cpascii(lgr_info->name, si->name, sizeof(si->name));
 	memcpy(&lgr_info->lpar_number, &si->lpar_number,
@@ -108,7 +98,7 @@ static void lgr_stsi_3_2_2(struct lgr_info *lgr_info)
 	struct sysinfo_3_2_2 *si = (void *) lgr_page;
 	int i;
 
-	if (stsi(si, 3, 2, 2) == -ENOSYS)
+	if (stsi(si, 3, 2, 2))
 		return;
 	for (i = 0; i < min_t(u8, si->count, VM_LEVEL_MAX); i++) {
 		cpascii(lgr_info->vm[i].name, si->vm[i].name,
@@ -124,16 +114,17 @@ static void lgr_stsi_3_2_2(struct lgr_info *lgr_info)
  */
 static void lgr_info_get(struct lgr_info *lgr_info)
 {
+	int level;
+
 	memset(lgr_info, 0, sizeof(*lgr_info));
 	stfle(lgr_info->stfle_fac_list, ARRAY_SIZE(lgr_info->stfle_fac_list));
-	lgr_info->level = stsi_0();
-	if (lgr_info->level == -ENOSYS)
-		return;
-	if (lgr_info->level >= 1)
+	level = stsi(NULL, 0, 0, 0);
+	lgr_info->level = level;
+	if (level >= 1)
 		lgr_stsi_1_1_1(lgr_info);
-	if (lgr_info->level >= 2)
+	if (level >= 2)
 		lgr_stsi_2_2_2(lgr_info);
-	if (lgr_info->level >= 3)
+	if (level >= 3)
 		lgr_stsi_3_2_2(lgr_info);
 }
 
diff --git a/arch/s390/kernel/sysinfo.c b/arch/s390/kernel/sysinfo.c
index 2af4ee67fe52..62f89d98e880 100644
--- a/arch/s390/kernel/sysinfo.c
+++ b/arch/s390/kernel/sysinfo.c
@@ -24,18 +24,38 @@
 
 int topology_max_mnest;
 
-static inline int stsi_0(void)
+/*
+ * stsi - store system information
+ *
+ * Returns the current configuration level if function code 0 was specified.
+ * Otherwise returns 0 on success or a negative value on error.
+ */
+int stsi(void *sysinfo, int fc, int sel1, int sel2)
 {
-	int rc = stsi(NULL, 0, 0, 0);
-
-	return rc == -ENOSYS ? rc : (((unsigned int) rc) >> 28);
+	register int r0 asm("0") = (fc << 28) | sel1;
+	register int r1 asm("1") = sel2;
+	int rc = 0;
+
+	asm volatile(
+		"	stsi	0(%3)\n"
+		"0:	jz	2f\n"
+		"1:	lhi	%1,%4\n"
+		"2:\n"
+		EX_TABLE(0b, 1b)
+		: "+d" (r0), "+d" (rc)
+		: "d" (r1), "a" (sysinfo), "K" (-EOPNOTSUPP)
+		: "cc", "memory");
+	if (rc)
+		return rc;
+	return fc ? 0 : ((unsigned int) r0) >> 28;
 }
+EXPORT_SYMBOL(stsi);
 
 static void stsi_1_1_1(struct seq_file *m, struct sysinfo_1_1_1 *info)
 {
 	int i;
 
-	if (stsi(info, 1, 1, 1) == -ENOSYS)
+	if (stsi(info, 1, 1, 1))
 		return;
 	EBCASC(info->manufacturer, sizeof(info->manufacturer));
 	EBCASC(info->type, sizeof(info->type));
@@ -97,7 +117,8 @@ static void stsi_15_1_x(struct seq_file *m, struct sysinfo_15_1_x *info)
 	seq_putc(m, '\n');
 	if (!MACHINE_HAS_TOPOLOGY)
 		return;
-	stsi(info, 15, 1, topology_max_mnest);
+	if (stsi(info, 15, 1, topology_max_mnest))
+		return;
 	seq_printf(m, "CPU Topology HW:     ");
 	for (i = 0; i < TOPOLOGY_NR_MAG; i++)
 		seq_printf(m, " %d", info->mag[i]);
@@ -116,7 +137,7 @@ static void stsi_1_2_2(struct seq_file *m, struct sysinfo_1_2_2 *info)
 	struct sysinfo_1_2_2_extension *ext;
 	int i;
 
-	if (stsi(info, 1, 2, 2) == -ENOSYS)
+	if (stsi(info, 1, 2, 2))
 		return;
 	ext = (struct sysinfo_1_2_2_extension *)
 		((unsigned long) info + info->acc_offset);
@@ -152,7 +173,7 @@ static void stsi_1_2_2(struct seq_file *m, struct sysinfo_1_2_2 *info)
 
 static void stsi_2_2_2(struct seq_file *m, struct sysinfo_2_2_2 *info)
 {
-	if (stsi(info, 2, 2, 2) == -ENOSYS)
+	if (stsi(info, 2, 2, 2))
 		return;
 	EBCASC(info->name, sizeof(info->name));
 	seq_putc(m, '\n');
@@ -179,7 +200,7 @@ static void stsi_3_2_2(struct seq_file *m, struct sysinfo_3_2_2 *info)
 {
 	int i;
 
-	if (stsi(info, 3, 2, 2) == -ENOSYS)
+	if (stsi(info, 3, 2, 2))
 		return;
 	for (i = 0; i < info->count; i++) {
 		EBCASC(info->vm[i].name, sizeof(info->vm[i].name));
@@ -202,7 +223,7 @@ static int sysinfo_show(struct seq_file *m, void *v)
 
 	if (!info)
 		return 0;
-	level = stsi_0();
+	level = stsi(NULL, 0, 0, 0);
 	if (level >= 1)
 		stsi_1_1_1(m, info);
 	if (level >= 1)
@@ -365,7 +386,7 @@ void s390_adjust_jiffies(void)
 	if (!info)
 		return;
 
-	if (stsi(info, 1, 2, 2) != -ENOSYS) {
+	if (stsi(info, 1, 2, 2) == 0) {
 		/*
 		 * Major sigh. The cpu capability encoding is "special".
 		 * If the first 9 bits of info->capability are 0 then it