powerpc fixes for 4.15 #3

Two fixes for nasty kexec/kdump crashes in certain configurations.
 
 A couple of minor fixes for the new TIDR code.
 
 A fix for an oops in a CXL error handling path.
 
 Thanks to:
   Andrew Donnellan, Christophe Lombard, David Gibson, Mahesh Salgaonkar, Vaibhav Jain.
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Merge tag 'powerpc-4.15-3' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux

Pull powerpc fixes from Michael Ellerman:
 "Two fixes for nasty kexec/kdump crashes in certain configurations.

  A couple of minor fixes for the new TIDR code.

  A fix for an oops in a CXL error handling path.

  Thanks to: Andrew Donnellan, Christophe Lombard, David Gibson, Mahesh
  Salgaonkar, Vaibhav Jain"

* tag 'powerpc-4.15-3' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
  powerpc: Do not assign thread.tidr if already assigned
  powerpc: Avoid signed to unsigned conversion in set_thread_tidr()
  powerpc/kexec: Fix kexec/kdump in P9 guest kernels
  powerpc/powernv: Fix kexec crashes caused by tlbie tracing
  cxl: Check if vphb exists before iterating over AFU devices

arch/powerpc/kernel/misc_64.S

@@ -623,7 +623,9 @@ BEGIN_FTR_SECTION
 	 * NOTE, we rely on r0 being 0 from above.
 	 */
 	mtspr	SPRN_IAMR,r0
+BEGIN_FTR_SECTION_NESTED(42)
 	mtspr	SPRN_AMOR,r0
+END_FTR_SECTION_NESTED_IFSET(CPU_FTR_HVMODE, 42)
 END_FTR_SECTION_IFSET(CPU_FTR_ARCH_300)
 
 	/* save regs for local vars on new stack.

arch/powerpc/kernel/process.c

@@ -1569,16 +1569,22 @@ void arch_release_task_struct(struct task_struct *t)
  */
 int set_thread_tidr(struct task_struct *t)
 {
+	int rc;
+
 	if (!cpu_has_feature(CPU_FTR_ARCH_300))
 		return -EINVAL;
 
 	if (t != current)
 		return -EINVAL;
 
-	t->thread.tidr = assign_thread_tidr();
+	if (t->thread.tidr)
-	if (t->thread.tidr < 0)
+		return 0;
-		return t->thread.tidr;
 
+	rc = assign_thread_tidr();
+	if (rc < 0)
+		return rc;
+
+	t->thread.tidr = rc;
 	mtspr(SPRN_TIDR, t->thread.tidr);
 
 	return 0;

arch/powerpc/mm/hash_native_64.c

@@ -47,7 +47,8 @@
 
 DEFINE_RAW_SPINLOCK(native_tlbie_lock);
 
-static inline void __tlbie(unsigned long vpn, int psize, int apsize, int ssize)
+static inline unsigned long  ___tlbie(unsigned long vpn, int psize,
+						int apsize, int ssize)
 {
 	unsigned long va;
 	unsigned int penc;
@@ -100,7 +101,15 @@ static inline void __tlbie(unsigned long vpn, int psize, int apsize, int ssize)
 			     : "memory");
 		break;
 	}
-	trace_tlbie(0, 0, va, 0, 0, 0, 0);
+	return va;
+}
+
+static inline void __tlbie(unsigned long vpn, int psize, int apsize, int ssize)
+{
+	unsigned long rb;
+
+	rb = ___tlbie(vpn, psize, apsize, ssize);
+	trace_tlbie(0, 0, rb, 0, 0, 0, 0);
 }
 
 static inline void __tlbiel(unsigned long vpn, int psize, int apsize, int ssize)
@@ -652,7 +661,7 @@ static void native_hpte_clear(void)
 		if (hpte_v & HPTE_V_VALID) {
 			hpte_decode(hptep, slot, &psize, &apsize, &ssize, &vpn);
 			hptep->v = 0;
-			__tlbie(vpn, psize, apsize, ssize);
+			___tlbie(vpn, psize, apsize, ssize);
 		}
 	}
 

drivers/misc/cxl/pci.c

@@ -2083,6 +2083,9 @@ static pci_ers_result_t cxl_vphb_error_detected(struct cxl_afu *afu,
 	/* There should only be one entry, but go through the list
 	 * anyway
 	 */
+	if (afu->phb == NULL)
+		return result;
+
 	list_for_each_entry(afu_dev, &afu->phb->bus->devices, bus_list) {
 		if (!afu_dev->driver)
 			continue;
@@ -2124,8 +2127,7 @@ static pci_ers_result_t cxl_pci_error_detected(struct pci_dev *pdev,
 			 * Tell the AFU drivers; but we don't care what they
 			 * say, we're going away.
 			 */
-			if (afu->phb != NULL)
+			cxl_vphb_error_detected(afu, state);
-				cxl_vphb_error_detected(afu, state);
 		}
 		return PCI_ERS_RESULT_DISCONNECT;
 	}
@@ -2265,6 +2267,9 @@ static pci_ers_result_t cxl_pci_slot_reset(struct pci_dev *pdev)
 		if (cxl_afu_select_best_mode(afu))
 			goto err;
 
+		if (afu->phb == NULL)
+			continue;
+
 		list_for_each_entry(afu_dev, &afu->phb->bus->devices, bus_list) {
 			/* Reset the device context.
 			 * TODO: make this less disruptive
@@ -2327,6 +2332,9 @@ static void cxl_pci_resume(struct pci_dev *pdev)
 	for (i = 0; i < adapter->slices; i++) {
 		afu = adapter->afu[i];
 
+		if (afu->phb == NULL)
+			continue;
+
 		list_for_each_entry(afu_dev, &afu->phb->bus->devices, bus_list) {
 			if (afu_dev->driver && afu_dev->driver->err_handler &&
 			    afu_dev->driver->err_handler->resume)