Issue eclipse-omr#142 use the correct z/OS control block field to cal…

…culate physical memory

On z/OS, omrsysinfo_get_physical_memory() uses the CVTRLSTG field which returns the
amount of physical memory at IPL.
This value may not be correct at the time due to reconfigurable memory.
The correct field is RCEPOOL.

Signed-off-by: Peter Bain <[email protected]>

port/port_objects.mk

@@ -46,7 +46,6 @@ ifeq (zos,$(OMR_HOST_OS))
   OBJECTS += j9sysinfo_get_number_CPUs
   OBJECTS += j9jobname
   OBJECTS += j9userid
-  OBJECTS += j9sysinfo_get_physical_memory
   OBJECTS += j9csrsi
   OBJECTS += j9csrsi_wrp
   OBJECTS += j9zfs

port/unix/omrsysinfo.c

@@ -63,6 +63,7 @@
 #endif
 
 #if defined(J9ZOS390)
+#include "omrsimap.h"
 #include "omrsysinfo_helpers.h"
 #include "omrcsrsi.h"
 #endif /* defined(J9ZOS390) */
@@ -151,10 +152,6 @@
 #pragma map (Get_Number_Of_CPUs,"GETNCPUS")
 uintptr_t Get_Number_Of_CPUs();
 
-#pragma linkage (GETPHYM,OS)
-#pragma map (Get_Physical_Memory,"GETPHYM")
-uintptr_t Get_Physical_Memory();
-
 #endif
 
 #define JIFFIES			100
@@ -1441,8 +1438,11 @@ omrsysinfo_get_physical_memory(struct OMRPortLibrary *portLibrary)
 	/* on systems with 43K headers. However, this is not an issue as we only support AIX 5.2 and above only */
 	return (uint64_t) _system_configuration.physmem;
 #elif defined(J9ZOS390)
-	/* Get_Physical_Memory returns "SIZE OF ACTUAL REAL STORAGE ONLINE IN 'K'" */
-	return (uint64_t)Get_Physical_Memory() * 1024;
+	U_64 result = 0;
+	J9CVT * __ptr32 cvtp = ((J9PSA * __ptr32)0)->flccvt;
+	J9RCE * __ptr32 rcep = cvtp->cvtrcep;
+	result = ((U_64)rcep->rcepool * J9BYTES_PER_PAGE);
+	return result;
 #elif defined(OSX)
 	int name[2] = {CTL_HW, HW_MEMSIZE};
 	uint64_t size = 0;