Allow kernel to shutdown-to-payload.

   This code is currently unused, due to InitService not having the
   payload address and the start_host_os IPL step being unimplemented.

   For testing purposes the 'shutdown' call in initservice.C can be
   changed to pass a non-zero base address (such as 256MB).

RTC: 40871
Change-Id: I0f4b6bae62ede1853aabbcb28082300005e31897
Reviewed-on: http://gfw160.austin.ibm.com:8080/gerrit/926
Reviewed-by: A. Patrick Williams III <iawillia@us.ibm.com>
Tested-by: Jenkins Server
Reviewed-by: Douglas R. Gilbert <dgilbert@us.ibm.com>

11 files changed, 142 insertions, 10 deletions

diff --git a/src/include/kernel/cpumgr.H b/src/include/kernel/cpumgr.H
index 3be17192c..4374d50a0 100644
--- a/src/include/kernel/cpumgr.H
+++ b/src/include/kernel/cpumgr.H
@@ -81,6 +81,11 @@ class CpuManager
          */
         static void activateCPU(cpu_t * i_cpu);
 
+        /** @fn getCpuCount
+         * Return the number of active CPUs.
+         */
+        static size_t getCpuCount() { return cv_cpuCount; }
+
 
     protected:
         CpuManager();
diff --git a/src/include/kernel/misc.H b/src/include/kernel/misc.H
index 4be79d641..f04439748 100644
--- a/src/include/kernel/misc.H
+++ b/src/include/kernel/misc.H
@@ -35,5 +35,10 @@ namespace KernelMisc
      *  @brief Sequence kernel to shutdown and switch to payload.
      */
     void shutdown();
+
+    /** @brief Base address (target HRMOR) of the payload. */
+    extern uint64_t g_payload_base;
+    /** @brief Address from base of payload entry-point. */
+    extern uint64_t g_payload_entry;
 };
 #endif
diff --git a/src/include/kernel/ppcconsts.S b/src/include/kernel/ppcconsts.S
index 6aa53a6cd..89a52a008 100644
--- a/src/include/kernel/ppcconsts.S
+++ b/src/include/kernel/ppcconsts.S
@@ -156,6 +156,7 @@
                 .set HSPRG1,305
                 .set HDSISR,306
                 .set HDEC,310
+                .set HRMOR,313
                 .set HSRR0,314
                 .set HSRR1,315
                 .set HMER,336
diff --git a/src/include/sys/misc.h b/src/include/sys/misc.h
index d07c5afff..fcf88f08a 100644
--- a/src/include/sys/misc.h
+++ b/src/include/sys/misc.h
@@ -49,9 +49,14 @@ extern "C"
 #ifdef __HIDDEN_SYSCALL_SHUTDOWN
 /** @fn shutdown()
  *  @brief Shutdown all CPUs (hardware threads)
- *  @param[in] i_status The status code to post
+ *  @param[in] i_status         The status code to post
+ *  @param[in] i_payload_base   The base address (target HRMOR) of the payload.
+ *  @param[in] i_payload_entry  The offset from base address of the payload
+ *                              entry-point.
  */
-extern "C" void shutdown(uint64_t i_status);
+extern "C" void shutdown(uint64_t i_status,
+                         uint64_t i_payload_base,
+                         uint64_t i_payload_entry);
 #endif
 
 /** @enum ProcessorCoreType
diff --git a/src/kernel/cpumgr.C b/src/kernel/cpumgr.C
index 33290ebf1..f995eb543 100644
--- a/src/kernel/cpumgr.C
+++ b/src/kernel/cpumgr.C
@@ -107,8 +107,9 @@ void CpuManager::init_slave_smp(cpu_t* cpu)
 
 void CpuManager::requestShutdown(uint64_t i_status)
 {
-    cv_shutdown_requested = true;
     cv_shutdown_status = i_status;
+    __sync_synchronize();
+    cv_shutdown_requested = true;
 }
 
 void CpuManager::startCPU(ssize_t i)
diff --git a/src/kernel/misc.C b/src/kernel/misc.C
index 513844875..74be12de1 100644
--- a/src/kernel/misc.C
+++ b/src/kernel/misc.C
@@ -24,9 +24,17 @@
 #include <kernel/cpumgr.H>
 #include <kernel/cpuid.H>
 #include <kernel/console.H>
+#include <kernel/barrier.H>
+
+extern "C" void kernel_shutdown(size_t, uint64_t, uint64_t) NO_RETURN;
+
 
 namespace KernelMisc
 {
+
+    uint64_t g_payload_base = 0;
+    uint64_t g_payload_entry = 0;
+
     void shutdown()
     {
         // Update scratch SPR for shutdown status.
@@ -65,9 +73,37 @@ namespace KernelMisc
         // for exactly how this is handled.
         MAGIC_INSTRUCTION(MAGIC_SHUTDOWN);
 
-        while(1)
+        // Check for a valid payload address.
+        if ((0 == g_payload_base) && (0 == g_payload_entry))
         {
-            doze();
+            // We really don't know what we're suppose to do now, so just
+            // sleep all the processors.
+
+            if (c->master)
+            {
+                printk("No payload... doze'ing all threads.\n");
+            }
+
+            while(1)
+            {
+                doze();
+            }
+        }
+        else
+        {
+            static Barrier* l_barrier = new Barrier(CpuManager::getCpuCount());
+
+            if (c->master)
+            {
+                printk("Preparing to enter payload...%lx:%lx\n",
+                       g_payload_base, g_payload_entry);
+            }
+
+            l_barrier->wait();
+
+            kernel_shutdown(CpuManager::getCpuCount(),
+                            g_payload_base,
+                            g_payload_entry);
         }
     }
 };
diff --git a/src/kernel/start.S b/src/kernel/start.S
index c5af8652f..6d0eab195 100644
--- a/src/kernel/start.S
+++ b/src/kernel/start.S
@@ -640,6 +640,67 @@ task_end_stub:
     li r4, 0  ;// NULL -> r4 (status value)
     sc
 
+    ;// @fn kernel_shutdown
+    ;// Leave the Hostboot kernel and switch to the payload.
+    ;//
+    ;// This code must first move itself into "EA[0]=1" mode, migrate to a
+    ;// new HRMOR, and then jump to the new code.  The migration of the
+    ;// HRMOR must be synchronized, since the HRMOR is a core-shared SPR, so
+    ;// we must first ensure that all threads are in "EA[0]=1" mode.
+    ;//
+    ;// @param[in] r3 - CPU count - Number of active CPUs.
+    ;// @param[in] r4 - Payload Base
+    ;// @param[in] r5 - Payload Entry
+.global kernel_shutdown
+kernel_shutdown:
+        ;// Set R6 to 0x8000000000000000 so we can set "EA[0]=1" for addrs.
+    li r6, 1
+    rotldi r6, r6, 63
+        ;// Retrieve existing HRMOR.
+    mfspr r7, HRMOR
+        ;// Determine physical address of shutdown_barrier.
+    lis r8, kernel_shutdown_barrier@h
+    ori r8, r8, kernel_shutdown_barrier@l
+    or r8, r8, r7       ;// Apply HRMOR.
+    or r8, r8, r6       ;// Apply EA[0] = 1.
+        ;// Determine physical address of EA[0]=1 mode instruction.
+    lis r9, kernel_shutdown_ea0_1_mode@h
+    ori r9, r9, kernel_shutdown_ea0_1_mode@l
+    or r9, r9, r7       ;// Apply HRMOR.
+    or r9, r9, r6       ;// Apply EA[0] = 1.
+        ;// Jump to enter EA[0] = 1
+    mtlr r9
+    blr
+kernel_shutdown_ea0_1_mode:
+        ;// Perform barrier
+        ;//     Increment thread count.
+1:
+    ldarx r11, 0, r8
+    addi r11, r11, 1
+    stdcx. r11, 0, r8
+    bne- 1b
+    isync
+        ;//     Wait for count to reach CPU count.
+1:
+    or 1,1,1    ;// Drop thread priority
+    ld r11, 0(r8)
+    cmpd cr0, r11, r3
+    bne 1b
+        ;//     Instruction barrier to ensure exit.
+    isync
+    or 3,3,3    ;// Increase thread priority
+        ;// Update HRMOR.
+        ;// TODO: There might be more to it than just this, such as clearing
+        ;//       ERATs but this works for now in Simics.
+    mtspr HRMOR, r4
+        ;// Set HSRR0 to entry point.
+    mtspr HSRR0, r5
+        ;// Save MSR, move to HSRR1.
+    mfmsr r10
+    mtspr HSRR1, r10
+        ;// TODO: Any updates we need to do to HSRR1/MSR for payload?
+        ;// Jump to entry point. Causes HSRR0 -> NIA, HSSR1 -> MSR.
+    hrfid
 
 STD_INTERRUPT_NOADDR(hype_emu_assist)
 
@@ -652,6 +713,9 @@ kernel_stack:
 kernel_other_thread_spinlock:
     .space 8
 
+kernel_shutdown_barrier:
+    .space 8
+
 .global hbi_ImageId
 hbi_ImageId:
     .space 128
diff --git a/src/kernel/syscall.C b/src/kernel/syscall.C
index 4d723852f..cfcbed860 100644
--- a/src/kernel/syscall.C
+++ b/src/kernel/syscall.C
@@ -604,6 +604,8 @@ namespace Systemcalls
     void Shutdown(task_t * t)
     {
         uint64_t status = static_cast<uint64_t>(TASK_GETARG0(t));
+        KernelMisc::g_payload_base = static_cast<uint64_t>(TASK_GETARG1(t));
+        KernelMisc::g_payload_entry = static_cast<uint64_t>(TASK_GETARG2(t));
         CpuManager::requestShutdown(status);
         TASK_SETRTN(t, 0);
     }
diff --git a/src/lib/syscall_misc.C b/src/lib/syscall_misc.C
index 897012daa..539399b7a 100644
--- a/src/lib/syscall_misc.C
+++ b/src/lib/syscall_misc.C
@@ -27,9 +27,14 @@
 
 using namespace Systemcalls;
 
-void shutdown(uint64_t i_status)
+void shutdown(uint64_t i_status,
+              uint64_t i_payload_base,
+              uint64_t i_payload_entry)
 {
-    _syscall1(MISC_SHUTDOWN, reinterpret_cast<void*>(i_status));
+    _syscall3(MISC_SHUTDOWN,
+                reinterpret_cast<void*>(i_status),
+                reinterpret_cast<void*>(i_payload_base),
+                reinterpret_cast<void*>(i_payload_entry));
 }
 
 ProcessorCoreType cpu_core_type()
diff --git a/src/usr/initservice/baseinitsvc/initservice.C b/src/usr/initservice/baseinitsvc/initservice.C
index c352d5353..e9b6b25c2 100644
--- a/src/usr/initservice/baseinitsvc/initservice.C
+++ b/src/usr/initservice/baseinitsvc/initservice.C
@@ -610,7 +610,9 @@ void InitService::registerBlock(void* i_vaddr, uint64_t i_size,
     }
 }
 
-void InitService::doShutdown(uint64_t i_status)
+void InitService::doShutdown(uint64_t i_status,
+                             uint64_t i_payload_base,
+                             uint64_t i_payload_entry)
 {
     int l_rc = 0;
     errlHndl_t l_err = NULL;
@@ -643,7 +645,7 @@ void InitService::doShutdown(uint64_t i_status)
         }
         l_rb_iter++;
     }
-    shutdown(i_status);
+    shutdown(i_status, i_payload_base, i_payload_entry);
 }
 
 } // namespace
diff --git a/src/usr/initservice/baseinitsvc/initservice.H b/src/usr/initservice/baseinitsvc/initservice.H
index d80c5d2ef..8c8badbbd 100644
--- a/src/usr/initservice/baseinitsvc/initservice.H
+++ b/src/usr/initservice/baseinitsvc/initservice.H
@@ -177,10 +177,16 @@ public:
      * @brief Perform necessary steps, such as FLUSHing, to registered blocks.
      *
      * @param[in] i_status - Shutdown status to be passed along on shutdown
+     * @param[in] i_payload_base - The base address (target HRMOR) of the
+     *                             payload.
+     * @param[in] i_payload_entry - The offset from base address of the
+     *                              payload entry-point.
      *
      * @return Nothing
      */
-    void doShutdown(uint64_t i_status);
+    void doShutdown(uint64_t i_status,
+                    uint64_t i_payload_base = 0,
+                    uint64_t i_payload_entry = 0);
 
 
 protected: