Merge tag 'powerpc-4.12-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux

Pull powerpc updates from Michael Ellerman:
 "Highlights include:

   - Larger virtual address space on 64-bit server CPUs. By default we
     use a 128TB virtual address space, but a process can request access
     to the full 512TB by passing a hint to mmap().

   - Support for the new Power9 "XIVE" interrupt controller.

   - TLB flushing optimisations for the radix MMU on Power9.

   - Support for CAPI cards on Power9, using the "Coherent Accelerator
     Interface Architecture 2.0".

   - The ability to configure the mmap randomisation limits at build and
     runtime.

   - Several small fixes and cleanups to the kprobes code, as well as
     support for KPROBES_ON_FTRACE.

   - Major improvements to handling of system reset interrupts,
     correctly treating them as NMIs, giving them a dedicated stack and
     using a new hypervisor call to trigger them, all of which should
     aid debugging and robustness.

   - Many fixes and other minor enhancements.

  Thanks to: Alastair D'Silva, Alexey Kardashevskiy, Alistair Popple,
  Andrew Donnellan, Aneesh Kumar K.V, Anshuman Khandual, Anton
  Blanchard, Balbir Singh, Ben Hutchings, Benjamin Herrenschmidt,
  Bhupesh Sharma, Chris Packham, Christian Zigotzky, Christophe Leroy,
  Christophe Lombard, Daniel Axtens, David Gibson, Gautham R. Shenoy,
  Gavin Shan, Geert Uytterhoeven, Guilherme G. Piccoli, Hamish Martin,
  Hari Bathini, Kees Cook, Laurent Dufour, Madhavan Srinivasan, Mahesh J
  Salgaonkar, Mahesh Salgaonkar, Masami Hiramatsu, Matt Brown, Matthew
  R. Ochs, Michael Neuling, Naveen N. Rao, Nicholas Piggin, Oliver
  O'Halloran, Pan Xinhui, Paul Mackerras, Rashmica Gupta, Russell
  Currey, Sukadev Bhattiprolu, Thadeu Lima de Souza Cascardo, Tobin C.
  Harding, Tyrel Datwyler, Uma Krishnan, Vaibhav Jain, Vipin K Parashar,
  Yang Shi"

* tag 'powerpc-4.12-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (214 commits)
  powerpc/64s: Power9 has no LPCR[VRMASD] field so don't set it
  powerpc/powernv: Fix TCE kill on NVLink2
  powerpc/mm/radix: Drop support for CPUs without lockless tlbie
  powerpc/book3s/mce: Move add_taint() later in virtual mode
  powerpc/sysfs: Move #ifdef CONFIG_HOTPLUG_CPU out of the function body
  powerpc/smp: Document irq enable/disable after migrating IRQs
  powerpc/mpc52xx: Don't select user-visible RTAS_PROC
  powerpc/powernv: Document cxl dependency on special case in pnv_eeh_reset()
  powerpc/eeh: Clean up and document event handling functions
  powerpc/eeh: Avoid use after free in eeh_handle_special_event()
  cxl: Mask slice error interrupts after first occurrence
  cxl: Route eeh events to all drivers in cxl_pci_error_detected()
  cxl: Force context lock during EEH flow
  powerpc/64: Allow CONFIG_RELOCATABLE if COMPILE_TEST
  powerpc/xmon: Teach xmon oops about radix vectors
  powerpc/mm/hash: Fix off-by-one in comment about kernel contexts ids
  powerpc/pseries: Enable VFIO
  powerpc/powernv: Fix iommu table size calculation hook for small tables
  powerpc/powernv: Check kzalloc() return value in pnv_pci_table_alloc
  powerpc: Add arch/powerpc/tools directory
  ...

1 files changed, 47 insertions, 89 deletions

diff --git a/drivers/misc/cxl/fault.c b/drivers/misc/cxl/fault.c
index 2fa015c05561..5344448f514e 100644
--- a/drivers/misc/cxl/fault.c
+++ b/drivers/misc/cxl/fault.c
@@ -146,108 +146,67 @@ static void cxl_handle_page_fault(struct cxl_context *ctx,
 		return cxl_ack_ae(ctx);
 	}
 
-	/*
-	 * update_mmu_cache() will not have loaded the hash since current->trap
-	 * is not a 0x400 or 0x300, so just call hash_page_mm() here.
-	 */
-	access = _PAGE_PRESENT | _PAGE_READ;
-	if (dsisr & CXL_PSL_DSISR_An_S)
-		access |= _PAGE_WRITE;
-
-	access |= _PAGE_PRIVILEGED;
-	if ((!ctx->kernel) || (REGION_ID(dar) == USER_REGION_ID))
-		access &= ~_PAGE_PRIVILEGED;
-
-	if (dsisr & DSISR_NOHPTE)
-		inv_flags |= HPTE_NOHPTE_UPDATE;
-
-	local_irq_save(flags);
-	hash_page_mm(mm, dar, access, 0x300, inv_flags);
-	local_irq_restore(flags);
-
+	if (!radix_enabled()) {
+		/*
+		 * update_mmu_cache() will not have loaded the hash since current->trap
+		 * is not a 0x400 or 0x300, so just call hash_page_mm() here.
+		 */
+		access = _PAGE_PRESENT | _PAGE_READ;
+		if (dsisr & CXL_PSL_DSISR_An_S)
+			access |= _PAGE_WRITE;
+
+		access |= _PAGE_PRIVILEGED;
+		if ((!ctx->kernel) || (REGION_ID(dar) == USER_REGION_ID))
+			access &= ~_PAGE_PRIVILEGED;
+
+		if (dsisr & DSISR_NOHPTE)
+			inv_flags |= HPTE_NOHPTE_UPDATE;
+
+		local_irq_save(flags);
+		hash_page_mm(mm, dar, access, 0x300, inv_flags);
+		local_irq_restore(flags);
+	}
 	pr_devel("Page fault successfully handled for pe: %i!\n", ctx->pe);
 	cxl_ops->ack_irq(ctx, CXL_PSL_TFC_An_R, 0);
 }
 
 /*
- * Returns the mm_struct corresponding to the context ctx via ctx->pid
- * In case the task has exited we use the task group leader accessible
- * via ctx->glpid to find the next task in the thread group that has a
- * valid  mm_struct associated with it. If a task with valid mm_struct
- * is found the ctx->pid is updated to use the task struct for subsequent
- * translations. In case no valid mm_struct is found in the task group to
- * service the fault a NULL is returned.
+ * Returns the mm_struct corresponding to the context ctx.
+ * mm_users == 0, the context may be in the process of being closed.
  */
 static struct mm_struct *get_mem_context(struct cxl_context *ctx)
 {
-	struct task_struct *task = NULL;
-	struct mm_struct *mm = NULL;
-	struct pid *old_pid = ctx->pid;
-
-	if (old_pid == NULL) {
-		pr_warn("%s: Invalid context for pe=%d\n",
-			 __func__, ctx->pe);
+	if (ctx->mm == NULL)
 		return NULL;
-	}
 
-	task = get_pid_task(old_pid, PIDTYPE_PID);
+	if (!atomic_inc_not_zero(&ctx->mm->mm_users))
+		return NULL;
 
-	/*
-	 * pid_alive may look racy but this saves us from costly
-	 * get_task_mm when the task is a zombie. In worst case
-	 * we may think a task is alive, which is about to die
-	 * but get_task_mm will return NULL.
-	 */
-	if (task != NULL && pid_alive(task))
-		mm = get_task_mm(task);
+	return ctx->mm;
+}
 
-	/* release the task struct that was taken earlier */
-	if (task)
-		put_task_struct(task);
-	else
-		pr_devel("%s: Context owning pid=%i for pe=%i dead\n",
-			__func__, pid_nr(old_pid), ctx->pe);
-
-	/*
-	 * If we couldn't find the mm context then use the group
-	 * leader to iterate over the task group and find a task
-	 * that gives us mm_struct.
-	 */
-	if (unlikely(mm == NULL && ctx->glpid != NULL)) {
-
-		rcu_read_lock();
-		task = pid_task(ctx->glpid, PIDTYPE_PID);
-		if (task)
-			do {
-				mm = get_task_mm(task);
-				if (mm) {
-					ctx->pid = get_task_pid(task,
-								PIDTYPE_PID);
-					break;
-				}
-				task = next_thread(task);
-			} while (task && !thread_group_leader(task));
-		rcu_read_unlock();
-
-		/* check if we switched pid */
-		if (ctx->pid != old_pid) {
-			if (mm)
-				pr_devel("%s:pe=%i switch pid %i->%i\n",
-					 __func__, ctx->pe, pid_nr(old_pid),
-					 pid_nr(ctx->pid));
-			else
-				pr_devel("%s:Cannot find mm for pid=%i\n",
-					 __func__, pid_nr(old_pid));
-
-			/* drop the reference to older pid */
-			put_pid(old_pid);
-		}
-	}
+static bool cxl_is_segment_miss(struct cxl_context *ctx, u64 dsisr)
+{
+	if ((cxl_is_psl8(ctx->afu)) && (dsisr & CXL_PSL_DSISR_An_DS))
+		return true;
 
-	return mm;
+	return false;
 }
 
+static bool cxl_is_page_fault(struct cxl_context *ctx, u64 dsisr)
+{
+	if ((cxl_is_psl8(ctx->afu)) && (dsisr & CXL_PSL_DSISR_An_DM))
+		return true;
+
+	if ((cxl_is_psl9(ctx->afu)) &&
+	   ((dsisr & CXL_PSL9_DSISR_An_CO_MASK) &
+		(CXL_PSL9_DSISR_An_PF_SLR | CXL_PSL9_DSISR_An_PF_RGC |
+		 CXL_PSL9_DSISR_An_PF_RGP | CXL_PSL9_DSISR_An_PF_HRH |
+		 CXL_PSL9_DSISR_An_PF_STEG)))
+		return true;
 
+	return false;
+}
 
 void cxl_handle_fault(struct work_struct *fault_work)
 {
@@ -282,7 +241,6 @@ void cxl_handle_fault(struct work_struct *fault_work)
 	if (!ctx->kernel) {
 
 		mm = get_mem_context(ctx);
-		/* indicates all the thread in task group have exited */
 		if (mm == NULL) {
 			pr_devel("%s: unable to get mm for pe=%d pid=%i\n",
 				 __func__, ctx->pe, pid_nr(ctx->pid));
@@ -294,9 +252,9 @@ void cxl_handle_fault(struct work_struct *fault_work)
 		}
 	}
 
-	if (dsisr & CXL_PSL_DSISR_An_DS)
+	if (cxl_is_segment_miss(ctx, dsisr))
 		cxl_handle_segment_miss(ctx, mm, dar);
-	else if (dsisr & CXL_PSL_DSISR_An_DM)
+	else if (cxl_is_page_fault(ctx, dsisr))
 		cxl_handle_page_fault(ctx, mm, dsisr, dar);
 	else
 		WARN(1, "cxl_handle_fault has nothing to handle\n");