powerpc/pseries: Add failure related checks for h_get_mpp and h_get_ppp

Couple of Minor fixes:

- hcall return values are long. Fix that for h_get_mpp, h_get_ppp and
parse_ppp_data

- If hcall fails, values set should be at-least zero. It shouldn't be
uninitialized values. Fix that for h_get_mpp and h_get_ppp
Signed-off-by: Shrikanth Hegde <sshegde@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20240412092047.455483-3-sshegde@linux.ibm.com

arch/powerpc/include/asm/hvcall.h

@@ -570,7 +570,7 @@ struct hvcall_mpp_data {
 	unsigned long backing_mem;
 };
 
-int h_get_mpp(struct hvcall_mpp_data *);
+long h_get_mpp(struct hvcall_mpp_data *mpp_data);
 
 struct hvcall_mpp_x_data {
 	unsigned long coalesced_bytes;

arch/powerpc/platforms/pseries/lpar.c

@@ -1886,10 +1886,10 @@ notrace void __trace_hcall_exit(long opcode, long retval, unsigned long *retbuf)
  * h_get_mpp
  * H_GET_MPP hcall returns info in 7 parms
  */
-int h_get_mpp(struct hvcall_mpp_data *mpp_data)
+long h_get_mpp(struct hvcall_mpp_data *mpp_data)
 {
-	int rc;
-	unsigned long retbuf[PLPAR_HCALL9_BUFSIZE];
+	unsigned long retbuf[PLPAR_HCALL9_BUFSIZE] = {0};
+	long rc;
 
 	rc = plpar_hcall9(H_GET_MPP, retbuf);
 

arch/powerpc/platforms/pseries/lparcfg.c

@@ -113,8 +113,8 @@ struct hvcall_ppp_data {
  */
 static unsigned int h_get_ppp(struct hvcall_ppp_data *ppp_data)
 {
-	unsigned long rc;
-	unsigned long retbuf[PLPAR_HCALL9_BUFSIZE];
+	unsigned long retbuf[PLPAR_HCALL9_BUFSIZE] = {0};
+	long rc;
 
 	rc = plpar_hcall9(H_GET_PPP, retbuf);
 
@@ -197,7 +197,7 @@ static void parse_ppp_data(struct seq_file *m)
 	struct hvcall_ppp_data ppp_data;
 	struct device_node *root;
 	const __be32 *perf_level;
-	int rc;
+	long rc;
 
 	rc = h_get_ppp(&ppp_data);
 	if (rc)