Method to execute testcases early in the boot

A new CONFIG variable has been created that will trigger the
istep dispatcher to start the CXX unit test execution at some
point during the boot rather than waiting until the end.  This
is useful for quick targeted testing and also for early bringup
of new platforms.

CONFIG_EARLY_TESTCASES is the new flag, and it uses
ATTR_EARLY_TESTCASES_ISTEP to determine where in the boot to stop.

Changes were required in several testcases to either skip the
test completely (typically due to not having enough memory) or
to add additional logic to load new support libraries on demand.

The Axone platform has this flag enabled by default to execute
testcases at the end of istep 6.9 (host_gard).

Change-Id: I1da9479e2147d68102f44d60e064c3b79cc41bb6
Reviewed-on: http://rchgit01.rchland.ibm.com/gerrit1/71693
Tested-by: Jenkins Server <pfd-jenkins+hostboot@us.ibm.com>
Tested-by: Jenkins OP Build CI <op-jenkins+hostboot@us.ibm.com>
Tested-by: Jenkins OP HW <op-hw-jenkins+hostboot@us.ibm.com>
Tested-by: FSP CI Jenkins <fsp-CI-jenkins+hostboot@us.ibm.com>
Reviewed-by: Christian R. Geddes <crgeddes@us.ibm.com>
Reviewed-by: Roland Veloz <rveloz@us.ibm.com>
Reviewed-by: Matt Derksen <mderkse1@us.ibm.com>
Reviewed-by: William G. Hoffa <wghoffa@us.ibm.com>

16 files changed, 234 insertions, 18 deletions

diff --git a/src/build/configs/simics_axone.config b/src/build/configs/simics_axone.config
index a71f5e2f7..385c86063 100644
--- a/src/build/configs/simics_axone.config
+++ b/src/build/configs/simics_axone.config
@@ -1,3 +1,4 @@
+#fetch dimm spd via i2c
 set DJVPD_READ_FROM_HW
 
 # You can enabled MVPD read from HW but adds time to IPL
@@ -6,7 +7,13 @@ set DJVPD_READ_FROM_HW
 #skip enabling checkstop analysis until OCC is ready in simics
 unset IPLTIME_CHECKSTOP_ANALYSIS
 
-set AXONE_BRING_UP
-
+#enable EEPROM caching
 set SUPPORT_EEPROM_CACHING
 
+#run cxx testcases during boot
+set EARLY_TESTCASES
+
+#Try to keep a list of things this does
+# - skipping setting voltages in istep 8.12, nothing on other side of AVSbus
+#   in simics currently.
+set AXONE_BRING_UP
diff --git a/src/makefile b/src/makefile
index 022711c91..b7f731b89 100644
--- a/src/makefile
+++ b/src/makefile
@@ -244,7 +244,7 @@ TESTCASE_MODULES += $(if $(CONFIG_VPO_COMPILE),,testmdia)
 TESTCASE_MODULES += testpirformat
 TESTCASE_MODULES += testi2c
 TESTCASE_MODULES += testmbox
-TESTCASE_MODULES += testrtloader
+TESTCASE_MODULES += $(if $(CONFIG_EARLY_TESTCASES),,testrtloader)
 TESTCASE_MODULES += testsbe
 TESTCASE_MODULES += testsbeio
 TESTCASE_MODULES += testerrl
@@ -255,7 +255,7 @@ TESTCASE_MODULES += testscom
 TESTCASE_MODULES += $(if $(CONFIG_VPO_COMPILE),,testruntime)
 TESTCASE_MODULES += testintr
 TESTCASE_MODULES += testfapi2
-TESTCASE_MODULES += $(if $(CONFIG_FSP_BUILD),,testnvram)
+TESTCASE_MODULES += $(if $(CONFIG_EARLY_TESTCASES) && $(FSP_BUILD) ,,testnvram)
 TESTCASE_MODULES += testsmf
 TESTCASE_MODULES += testexpscom
 
diff --git a/src/usr/cxxtest/HBconfig b/src/usr/cxxtest/HBconfig
new file mode 100644
index 000000000..aa2fd1b24
--- /dev/null
+++ b/src/usr/cxxtest/HBconfig
@@ -0,0 +1,6 @@
+config EARLY_TESTCASES
+    default n
+    help
+        Execute unit tests at the end of the istep specified in
+        EARLY_TESTCASES_ISTEP and then shut down.
+
diff --git a/src/usr/fapi2/test/fapi2MvpdTestCxx.H b/src/usr/fapi2/test/fapi2MvpdTestCxx.H
index dab243795..224879070 100644
--- a/src/usr/fapi2/test/fapi2MvpdTestCxx.H
+++ b/src/usr/fapi2/test/fapi2MvpdTestCxx.H
@@ -5,7 +5,7 @@
 /*                                                                        */
 /* OpenPOWER HostBoot Project                                             */
 /*                                                                        */
-/* Contributors Listed Below - COPYRIGHT 2016,2017                        */
+/* Contributors Listed Below - COPYRIGHT 2016,2019                        */
 /* [+] International Business Machines Corp.                              */
 /*                                                                        */
 /*                                                                        */
@@ -320,10 +320,15 @@ public:
 
   void testMvpdGetPoundVBucket(void)
   {
+      FAPI_INF("MvpdGetPoundVBucket Test entry... ");
       int numTests = 0;
       int numFails = 0;
+
+#ifdef CONFIG_EARLY_TESTCASES
+      // Requires some prereqs of step7
+      FAPI_INF("Skipping poundv tests");
+#else
       fapi2::ReturnCode   l_rc;
-      FAPI_INF("MvpdGetPoundVBucket Test entry... ");
 
       // Create a vector of TARGETING::Target pointers
       TARGETING::TargetHandleList l_chipletList;
@@ -403,6 +408,7 @@ public:
           FAPI_INF("Bucket for HUID: 0x%X is = %d", l_huid, voltageData.bucketId);
       }
 
+#endif
       FAPI_INF("MvpdGetPoundVBucket:: Test Complete. %d/%d fails",  numFails , numTests);
       FAPI_INF("MvpdGetPoundVBucket Test exit... ");
   }
@@ -411,9 +417,14 @@ public:
   {
       int numTests = 0;
       int numFails = 0;
-      fapi2::ReturnCode   l_rc;
       FAPI_INF("MvpdGetPoundWBucket Test entry... ");
 
+#ifdef CONFIG_EARLY_TESTCASES
+      // Requires some prereqs of step7
+      FAPI_INF("Skipping poundv tests");
+#else
+      fapi2::ReturnCode   l_rc;
+
       // Create a vector of TARGETING::Target pointers
       TARGETING::TargetHandleList l_chipletList;
 
@@ -471,6 +482,8 @@ public:
           FAPI_INF("Bucket for HUID: 0x%X is = %d", l_huid, vdmData.bucketId);
       }
 
+#endif
+
       FAPI_INF("MvpdGetPoundWBucket:: Test Complete. %d/%d fails",
                numFails,
                numTests);
diff --git a/src/usr/initservice/istepdispatcher/istepdispatcher.C b/src/usr/initservice/istepdispatcher/istepdispatcher.C
index 6500d1013..e9915aaf4 100644
--- a/src/usr/initservice/istepdispatcher/istepdispatcher.C
+++ b/src/usr/initservice/istepdispatcher/istepdispatcher.C
@@ -93,6 +93,8 @@
 #include <devicefw/userif.H>
 #include <p9_perv_scom_addresses.H>
 // ---------------------------
+#include <initservice/extinitserviceif.H>
+
 
 namespace ISTEPS_TRACE
 {
@@ -871,6 +873,9 @@ errlHndl_t IStepDispatcher::doIstep(uint32_t i_istep,
 
     do {
 
+    TARGETING::Target* l_pTopLevel = NULL;
+    TARGETING::targetService().getTopLevelTarget(l_pTopLevel);
+
     // If the step has valid work to be done, then execute it.
     if(NULL != theStep)
     {
@@ -973,8 +978,6 @@ errlHndl_t IStepDispatcher::doIstep(uint32_t i_istep,
         }
 
         // Zero ATTR_RECONFIGURE_LOOP
-        TARGETING::Target* l_pTopLevel = NULL;
-        TARGETING::targetService().getTopLevelTarget(l_pTopLevel);
         l_pTopLevel->setAttr<TARGETING::ATTR_RECONFIGURE_LOOP>(0);
 
         // Read ATTR_ISTEP_PAUSE_ENABLE attribute
@@ -1122,6 +1125,40 @@ errlHndl_t IStepDispatcher::doIstep(uint32_t i_istep,
                   INFO_MRK"doIstep: Empty Istep, nothing to do!" );
     }
 
+#ifdef CONFIG_EARLY_TESTCASES
+    // Check to see if we should run testcases here
+    TARGETING::ATTR_EARLY_TESTCASES_ISTEP_type l_runCxxIstep =
+      l_pTopLevel->getAttr<TARGETING::ATTR_EARLY_TESTCASES_ISTEP>();
+    if( (((i_istep & 0xFF) << 8) | (i_substep & 0xFF))
+        == l_runCxxIstep )
+    {
+        TRACFCOMP(g_trac_initsvc, "doIstep: Executing CXX testcases!");
+        uint32_t l_status = SHUTDOWN_STATUS_GOOD;
+
+        //  - Run CXX testcases
+        err = INITSERVICE::executeUnitTests();
+        if(err)
+        {
+            errlCommit (err, INITSVC_COMP_ID);
+            l_status = SHUTDOWN_STATUS_UT_FAILED;
+        }
+
+        //  - Call shutdown using payload base, and payload entry.
+        // NOTE: this call will not return if successful.
+        TARGETING::Target* l_pSys = NULL;
+        TARGETING::targetService().getTopLevelTarget( l_pSys );
+        uint64_t payloadBase =
+          l_pSys->getAttr<TARGETING::ATTR_PAYLOAD_BASE>();
+        payloadBase = (payloadBase * MEGABYTE);
+        uint64_t payloadEntry =
+          l_pSys->getAttr<TARGETING::ATTR_PAYLOAD_ENTRY>();
+        INITSERVICE::doShutdown( l_status,
+                                 false,
+                                 payloadBase,
+                                 payloadEntry );
+    }
+#endif
+
     } while (0); // if there was an error break here
 
     if (!err && theStep)
diff --git a/src/usr/runtime/test/hdatservicetest.H b/src/usr/runtime/test/hdatservicetest.H
index cfd70ddfb..0fff39e5b 100644
--- a/src/usr/runtime/test/hdatservicetest.H
+++ b/src/usr/runtime/test/hdatservicetest.H
@@ -5,7 +5,9 @@
 /*                                                                        */
 /* OpenPOWER HostBoot Project                                             */
 /*                                                                        */
-/* COPYRIGHT International Business Machines Corp. 2012,2014              */
+/* Contributors Listed Below - COPYRIGHT 2012,2019                        */
+/* [+] International Business Machines Corp.                              */
+/*                                                                        */
 /*                                                                        */
 /* Licensed under the Apache License, Version 2.0 (the "License");        */
 /* you may not use this file except in compliance with the License.       */
@@ -38,6 +40,7 @@
 #include "../hdatstructs.H"
 #include "../errlud_hdat.H"
 #include <runtime/runtime_reasoncodes.H>
+#include <vfs/vfs.H>
 
 /*
  * To test with a custom HDAT do the following:
@@ -441,6 +444,42 @@ class HdatServiceTest: public CxxTest::TestSuite
 #endif
     }
 
+    // Handle the case where we are running the testcases before the
+    //  libruntime.so module has been loaded
+    bool iv_loaded_libruntime;
+
+    HdatServiceTest()
+      : CxxTest::TestSuite(), iv_loaded_libruntime(false)
+    {
+        // Need to load up the runtime module if it isn't already loaded
+        if (  !VFS::module_is_loaded( "libruntime.so" ) )
+        {
+            errlHndl_t errhdl = VFS::module_load( "libruntime.so" );
+            if ( errhdl )
+            {
+                TS_FAIL("HdatServiceTest> Failed to load libruntime.so");
+                errlCommit(errhdl,RUNTIME_COMP_ID);
+            }
+            else
+            {
+                iv_loaded_libruntime = true;
+            }
+        }
+    }
+
+    ~HdatServiceTest()
+    {
+        if( iv_loaded_libruntime )
+        {
+            errlHndl_t errhdl = VFS::module_unload( "libruntime.so" );
+            if ( errhdl )
+            {
+                TS_FAIL("HdatServiceTest> Failed to unload libruntime.so");
+                errlCommit(errhdl,RUNTIME_COMP_ID);
+            }
+        }
+    }
+
 };
 
 
diff --git a/src/usr/runtime/test/makefile b/src/usr/runtime/test/makefile
index b948c1a16..a5fec043d 100644
--- a/src/usr/runtime/test/makefile
+++ b/src/usr/runtime/test/makefile
@@ -5,7 +5,7 @@
 #
 # OpenPOWER HostBoot Project
 #
-# Contributors Listed Below - COPYRIGHT 2012,2018
+# Contributors Listed Below - COPYRIGHT 2012,2019
 # [+] International Business Machines Corp.
 #
 #
@@ -24,7 +24,7 @@
 # IBM_PROLOG_END_TAG
 ROOTPATH = ../../../..
 MODULE = testruntime
-TESTS += testpreverifiedlidmgr.H
+TESTS += $(if $(CONFIG_EARLY_TESTCASES),,testpreverifiedlidmgr.H)
 TESTS += test_checkHbResMemLimit.H
 #@TODO RTC 132750
 #TESTS += hdatservicetest.H
diff --git a/src/usr/runtime/test/test_checkHbResMemLimit.H b/src/usr/runtime/test/test_checkHbResMemLimit.H
index e2ab9ca41..234f26426 100644
--- a/src/usr/runtime/test/test_checkHbResMemLimit.H
+++ b/src/usr/runtime/test/test_checkHbResMemLimit.H
@@ -32,6 +32,7 @@
 #include <runtime/interface.h>
 #include <runtime/runtime_reasoncodes.H>
 #include <vmmconst.h>
+#include <vfs/vfs.H>
 
 extern trace_desc_t* g_trac_runtime;
 
@@ -151,6 +152,43 @@ public:
         }while(0);
         TRACFCOMP(g_trac_runtime, "testAddressBelowHbResMemRange finished");
     }
+
+
+    // Handle the case where we are running the testcases before the
+    //  libruntime.so module has been loaded
+    bool iv_loaded_libruntime;
+
+    CheckHbResMemLimitTest()
+      : CxxTest::TestSuite(), iv_loaded_libruntime(false)
+    {
+        // Need to load up the runtime module if it isn't already loaded
+        if (  !VFS::module_is_loaded( "libruntime.so" ) )
+        {
+            errlHndl_t errhdl = VFS::module_load( "libruntime.so" );
+            if ( errhdl )
+            {
+                TS_FAIL("CheckHbResMemLimitTest> Failed to load libruntime.so");
+                errlCommit(errhdl,RUNTIME_COMP_ID);
+            }
+            else
+            {
+                iv_loaded_libruntime = true;
+            }
+        }
+    }
+
+    ~CheckHbResMemLimitTest()
+    {
+        if( iv_loaded_libruntime )
+        {
+            errlHndl_t errhdl = VFS::module_unload( "libruntime.so" );
+            if ( errhdl )
+            {
+                TS_FAIL("CheckHbResMemLimitTest> Failed to unload libruntime.so");
+                errlCommit(errhdl,RUNTIME_COMP_ID);
+            }
+        }
+    }
 };
 
 
diff --git a/src/usr/runtime/test/testpreverifiedlidmgr.H b/src/usr/runtime/test/testpreverifiedlidmgr.H
index 78fcbd95c..7b47bf98f 100644
--- a/src/usr/runtime/test/testpreverifiedlidmgr.H
+++ b/src/usr/runtime/test/testpreverifiedlidmgr.H
@@ -33,6 +33,7 @@
 #include <runtime/populate_hbruntime.H>
 #include <pnor/pnorif.H>
 #include <runtime/common/runtime_utils.H>
+#include <vfs/vfs.H>
 
 extern trace_desc_t* g_trac_runtime;
 
@@ -138,6 +139,42 @@ class PreVerifiedLidMgrTest : public CxxTest::TestSuite
 
         TRACFCOMP( g_trac_runtime, EXIT_MRK"testLoadFromPnor complete" );
     }
+
+    // Handle the case where we are running the testcases before the
+    //  libruntime.so module has been loaded
+    bool iv_loaded_libruntime;
+
+    PreVerifiedLidMgrTest()
+      : CxxTest::TestSuite(), iv_loaded_libruntime(false)
+    {
+        // Need to load up the runtime module if it isn't already loaded
+        if (  !VFS::module_is_loaded( "libruntime.so" ) )
+        {
+            errlHndl_t errhdl = VFS::module_load( "libruntime.so" );
+            if ( errhdl )
+            {
+                TS_FAIL("PreVerifiedLidMgrTest> Failed to load libruntime.so");
+                errlCommit(errhdl,RUNTIME_COMP_ID);
+            }
+            else
+            {
+                iv_loaded_libruntime = true;
+            }
+        }
+    }
+
+    ~PreVerifiedLidMgrTest()
+    {
+        if( iv_loaded_libruntime )
+        {
+            errlHndl_t errhdl = VFS::module_unload( "libruntime.so" );
+            if ( errhdl )
+            {
+                TS_FAIL("PreVerifiedLidMgrTest> Failed to unload libruntime.so");
+                errlCommit(errhdl,RUNTIME_COMP_ID);
+            }
+        }
+    }
 };
 
 #endif
diff --git a/src/usr/targeting/common/xmltohb/attribute_types_hb.xml b/src/usr/targeting/common/xmltohb/attribute_types_hb.xml
index c0cd729ed..89fad2f17 100755
--- a/src/usr/targeting/common/xmltohb/attribute_types_hb.xml
+++ b/src/usr/targeting/common/xmltohb/attribute_types_hb.xml
@@ -175,6 +175,23 @@
   </attribute>
 
   <attribute>
+    <id>EARLY_TESTCASES_ISTEP</id>
+    <description>
+        Indicates which istep we should execute the CXX testcases after, if
+        CONFIG_EARLY_TESTCASES is set.
+        Format: 0xMMmm, where MM=major step, mm=minor step, e.g. 6.9=0x0609.
+    </description>
+    <simpleType>
+      <uint16_t>
+        <!-- Default to running as soon as Hostboot is able -->
+        <default>0x0609</default>
+      </uint16_t>
+    </simpleType>
+    <persistency>non-volatile</persistency>
+    <readable/>
+  </attribute>
+
+  <attribute>
     <id>EEPROM_PAGE_ARRAY</id>
     <description>
         Used to keep track of which EEPROM page the current I2C master bus is set to
diff --git a/src/usr/targeting/common/xmltohb/simics_AXONE.system.xml b/src/usr/targeting/common/xmltohb/simics_AXONE.system.xml
index 124c0b13a..58ddcf9bd 100644
--- a/src/usr/targeting/common/xmltohb/simics_AXONE.system.xml
+++ b/src/usr/targeting/common/xmltohb/simics_AXONE.system.xml
@@ -343,6 +343,10 @@
         <id>X_EREPAIR_THRESHOLD_MNFG</id>
         <default>0</default>
     </attribute>
+    <attribute>
+        <id>EARLY_TESTCASES_ISTEP</id>
+        <default>0x0609</default>
+    </attribute>
 </targetInstance>
 
 <!-- ===================================================================== -->
diff --git a/src/usr/targeting/common/xmltohb/target_types_hb.xml b/src/usr/targeting/common/xmltohb/target_types_hb.xml
index a9cd859be..713eb7aa9 100644
--- a/src/usr/targeting/common/xmltohb/target_types_hb.xml
+++ b/src/usr/targeting/common/xmltohb/target_types_hb.xml
@@ -268,6 +268,9 @@
       <id>DRTM_PAYLOAD_ADDR_MB_HB</id>
     </attribute>
     <attribute>
+      <id>EARLY_TESTCASES_ISTEP</id>
+    </attribute>
+    <attribute>
       <id>FORCE_PRE_PAYLOAD_DRTM</id>
     </attribute>
     <attribute>
diff --git a/src/usr/util/test/makefile b/src/usr/util/test/makefile
index e6c4c69f8..43242d9dc 100644
--- a/src/usr/util/test/makefile
+++ b/src/usr/util/test/makefile
@@ -5,7 +5,9 @@
 #
 # OpenPOWER HostBoot Project
 #
-# COPYRIGHT International Business Machines Corp. 2012,2014
+# Contributors Listed Below - COPYRIGHT 2012,2019
+# [+] International Business Machines Corp.
+#
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -24,7 +26,10 @@ ROOTPATH = ../../../..
 
 MODULE = testutil
 
-TESTS = *.H
+TESTS += $(if $(CONFIG_EARLY_TESTCASES),,testmclmgr.H)
+TESTS += $(if $(CONFIG_EARLY_TESTCASES),,testtcemgr.H)
+TESTS += $(if $(CONFIG_EARLY_TESTCASES),,testlidmgr.H)
+TESTS += threadpool.H
 
 include ${ROOTPATH}/config.mk
 
diff --git a/src/usr/util/test/testlidmgr.H b/src/usr/util/test/testlidmgr.H
index 1644b1432..74342824c 100644
--- a/src/usr/util/test/testlidmgr.H
+++ b/src/usr/util/test/testlidmgr.H
@@ -5,7 +5,7 @@
 /*                                                                        */
 /* OpenPOWER HostBoot Project                                             */
 /*                                                                        */
-/* Contributors Listed Below - COPYRIGHT 2014,2017                        */
+/* Contributors Listed Below - COPYRIGHT 2014,2019                        */
 /* [+] International Business Machines Corp.                              */
 /*                                                                        */
 /*                                                                        */
@@ -47,6 +47,7 @@ public:
      */
     void testLidInPnorTest(void)
     {
+        UTIL_FT(INFO_MRK"testLidInPnorTest> Begin");
         errlHndl_t l_errl = NULL;
         size_t l_lidSize = 0;
         UtilLidMgr l_lidMgr(Util::TEST_LIDID);
@@ -129,6 +130,7 @@ public:
             }
             delete[] l_ptrTest;
         }while(0);
+        UTIL_FT(INFO_MRK"testLidInPnorTest> End");
     }
 
     /**
@@ -137,6 +139,7 @@ public:
      */
     void testLidInPnorOcc(void)
     {
+        UTIL_FT(INFO_MRK"testLidInPnorOcc> Begin");
         errlHndl_t l_errl = NULL;
 
         do
@@ -217,6 +220,7 @@ public:
                 TS_FAIL("testLidInPnorOcc: failed to release lid from PNOR");
             }
         }while(0);
+        UTIL_FT(INFO_MRK"testLidInPnorOcc> End");
     }
 };
 
diff --git a/src/usr/util/test/testmclmgr.H b/src/usr/util/test/testmclmgr.H
index 97c606a9d..b3398e165 100644
--- a/src/usr/util/test/testmclmgr.H
+++ b/src/usr/util/test/testmclmgr.H
@@ -33,6 +33,7 @@
 #include <usr/vmmconst.h>
 #include <runtime/preverifiedlidmgr.H>
 #include <util/util_reasoncodes.H>
+#include <util/utillidmgr.H>
 
 namespace MCL
 {
@@ -389,4 +390,4 @@ public:
     }
 };
 
-#endif
\ No newline at end of file
+#endif
diff --git a/src/usr/xscom/test/xscomtest.H b/src/usr/xscom/test/xscomtest.H
index 5bf9eaadd..2bb30ac12 100644
--- a/src/usr/xscom/test/xscomtest.H
+++ b/src/usr/xscom/test/xscomtest.H
@@ -5,7 +5,7 @@
 /*                                                                        */
 /* OpenPOWER HostBoot Project                                             */
 /*                                                                        */
-/* Contributors Listed Below - COPYRIGHT 2011,2018                        */
+/* Contributors Listed Below - COPYRIGHT 2011,2019                        */
 /* [+] International Business Machines Corp.                              */
 /*                                                                        */
 /*                                                                        */
@@ -404,6 +404,11 @@ public:
         uint32_t l_num;
 
         do {
+#ifdef CONFIG_EARLY_TESTCASES
+            TS_TRACE("testXscom4: Skipping test, multicast groups not setup yet");
+            break;
+#endif
+
             // Loop thru write table
             for( l_num=0; l_num < g_xscomMultiWriteTableSz; l_num++)
             {
@@ -459,7 +464,7 @@ public:
 
                 if( l_readData != l_testEntry.data )
                 {
-                    TS_FAIL("testXscom4: XSCom multicast read back doesn't match write!");
+                    TS_FAIL("testXscom4: XSCom multicast read back doesn't match write for %.8X!", l_testEntry.addr);
                     /*@
                     * @errortype
                     * @moduleid     XSCOM::XSCOM_TEST_XSCOM4