Merge tag 'powerpc-4.17-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux

Pull powerpc updates from Michael Ellerman:
 "Notable changes:

   - Support for 4PB user address space on 64-bit, opt-in via mmap().

   - Removal of POWER4 support, which was accidentally broken in 2016
     and no one noticed, and blocked use of some modern instructions.

   - Workarounds so that the hypervisor can enable Transactional Memory
     on Power9.

   - A series to disable the DAWR (Data Address Watchpoint Register) on
     Power9.

   - More information displayed in the meltdown/spectre_v1/v2 sysfs
     files.

   - A vpermxor (Power8 Altivec) implementation for the raid6 Q
     Syndrome.

   - A big series to make the allocation of our pacas (per cpu area),
     kernel page tables, and per-cpu stacks NUMA aware when using the
     Radix MMU on Power9.

  And as usual many fixes, reworks and cleanups.

  Thanks to: Aaro Koskinen, Alexandre Belloni, Alexey Kardashevskiy,
  Alistair Popple, Andy Shevchenko, Aneesh Kumar K.V, Anshuman Khandual,
  Balbir Singh, Benjamin Herrenschmidt, Christophe Leroy, Christophe
  Lombard, Cyril Bur, Daniel Axtens, Dave Young, Finn Thain, Frederic
  Barrat, Gustavo Romero, Horia Geantă, Jonathan Neuschäfer, Kees Cook,
  Larry Finger, Laurent Dufour, Laurent Vivier, Logan Gunthorpe,
  Madhavan Srinivasan, Mark Greer, Mark Hairgrove, Markus Elfring,
  Mathieu Malaterre, Matt Brown, Matt Evans, Mauricio Faria de Oliveira,
  Michael Neuling, Naveen N. Rao, Nicholas Piggin, Paul Mackerras,
  Philippe Bergheaud, Ram Pai, Rob Herring, Sam Bobroff, Segher
  Boessenkool, Simon Guo, Simon Horman, Stewart Smith, Sukadev
  Bhattiprolu, Suraj Jitindar Singh, Thiago Jung Bauermann, Vaibhav
  Jain, Vaidyanathan Srinivasan, Vasant Hegde, Wei Yongjun"

* tag 'powerpc-4.17-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (207 commits)
  powerpc/64s/idle: Fix restore of AMOR on POWER9 after deep sleep
  powerpc/64s: Fix POWER9 DD2.2 and above in cputable features
  powerpc/64s: Fix pkey support in dt_cpu_ftrs, add CPU_FTR_PKEY bit
  powerpc/64s: Fix dt_cpu_ftrs to have restore_cpu clear unwanted LPCR bits
  Revert "powerpc/64s/idle: POWER9 ESL=0 stop avoid save/restore overhead"
  powerpc: iomap.c: introduce io{read|write}64_{lo_hi|hi_lo}
  powerpc: io.h: move iomap.h include so that it can use readq/writeq defs
  cxl: Fix possible deadlock when processing page faults from cxllib
  powerpc/hw_breakpoint: Only disable hw breakpoint if cpu supports it
  powerpc/mm/radix: Update command line parsing for disable_radix
  powerpc/mm/radix: Parse disable_radix commandline correctly.
  powerpc/mm/hugetlb: initialize the pagetable cache correctly for hugetlb
  powerpc/mm/radix: Update pte fragment count from 16 to 256 on radix
  powerpc/mm/keys: Update documentation and remove unnecessary check
  powerpc/64s/idle: POWER9 ESL=0 stop avoid save/restore overhead
  powerpc/64s/idle: Consolidate power9_offline_stop()/power9_idle_stop()
  powerpc/powernv: Always stop secondaries before reboot/shutdown
  powerpc: hard disable irqs in smp_send_stop loop
  powerpc: use NMI IPI for smp_send_stop
  powerpc/powernv: Fix SMT4 forcing idle code
  ...

1 files changed, 56 insertions, 31 deletions

diff --git a/drivers/misc/cxl/cxllib.c b/drivers/misc/cxl/cxllib.c
index 30ccba436b3b..0bc7c31cf739 100644
--- a/drivers/misc/cxl/cxllib.c
+++ b/drivers/misc/cxl/cxllib.c
@@ -99,7 +99,7 @@ int cxllib_get_xsl_config(struct pci_dev *dev, struct cxllib_xsl_config *cfg)
 	if (rc)
 		return rc;
 
-	rc = cxl_get_xsl9_dsnctl(capp_unit_id, &cfg->dsnctl);
+	rc = cxl_get_xsl9_dsnctl(dev, capp_unit_id, &cfg->dsnctl);
 	if (rc)
 		return rc;
 	if (cpu_has_feature(CPU_FTR_POWER9_DD1)) {
@@ -208,49 +208,74 @@ int cxllib_get_PE_attributes(struct task_struct *task,
 }
 EXPORT_SYMBOL_GPL(cxllib_get_PE_attributes);
 
-int cxllib_handle_fault(struct mm_struct *mm, u64 addr, u64 size, u64 flags)
+static int get_vma_info(struct mm_struct *mm, u64 addr,
+			u64 *vma_start, u64 *vma_end,
+			unsigned long *page_size)
 {
-	int rc;
-	u64 dar;
 	struct vm_area_struct *vma = NULL;
-	unsigned long page_size;
-
-	if (mm == NULL)
-		return -EFAULT;
+	int rc = 0;
 
 	down_read(&mm->mmap_sem);
 
 	vma = find_vma(mm, addr);
 	if (!vma) {
-		pr_err("Can't find vma for addr %016llx\n", addr);
 		rc = -EFAULT;
 		goto out;
 	}
-	/* get the size of the pages allocated */
-	page_size = vma_kernel_pagesize(vma);
-
-	for (dar = (addr & ~(page_size - 1)); dar < (addr + size); dar += page_size) {
-		if (dar < vma->vm_start || dar >= vma->vm_end) {
-			vma = find_vma(mm, addr);
-			if (!vma) {
-				pr_err("Can't find vma for addr %016llx\n", addr);
-				rc = -EFAULT;
-				goto out;
-			}
-			/* get the size of the pages allocated */
-			page_size = vma_kernel_pagesize(vma);
+	*page_size = vma_kernel_pagesize(vma);
+	*vma_start = vma->vm_start;
+	*vma_end = vma->vm_end;
+out:
+	up_read(&mm->mmap_sem);
+	return rc;
+}
+
+int cxllib_handle_fault(struct mm_struct *mm, u64 addr, u64 size, u64 flags)
+{
+	int rc;
+	u64 dar, vma_start, vma_end;
+	unsigned long page_size;
+
+	if (mm == NULL)
+		return -EFAULT;
+
+	/*
+	 * The buffer we have to process can extend over several pages
+	 * and may also cover several VMAs.
+	 * We iterate over all the pages. The page size could vary
+	 * between VMAs.
+	 */
+	rc = get_vma_info(mm, addr, &vma_start, &vma_end, &page_size);
+	if (rc)
+		return rc;
+
+	for (dar = (addr & ~(page_size - 1)); dar < (addr + size);
+	     dar += page_size) {
+		if (dar < vma_start || dar >= vma_end) {
+			/*
+			 * We don't hold the mm->mmap_sem semaphore
+			 * while iterating, since the semaphore is
+			 * required by one of the lower-level page
+			 * fault processing functions and it could
+			 * create a deadlock.
+			 *
+			 * It means the VMAs can be altered between 2
+			 * loop iterations and we could theoretically
+			 * miss a page (however unlikely). But that's
+			 * not really a problem, as the driver will
+			 * retry access, get another page fault on the
+			 * missing page and call us again.
+			 */
+			rc = get_vma_info(mm, dar, &vma_start, &vma_end,
+					&page_size);
+			if (rc)
+				return rc;
 		}
 
 		rc = cxl_handle_mm_fault(mm, flags, dar);
-		if (rc) {
-			pr_err("cxl_handle_mm_fault failed %d", rc);
-			rc = -EFAULT;
-			goto out;
-		}
+		if (rc)
+			return -EFAULT;
 	}
-	rc = 0;
-out:
-	up_read(&mm->mmap_sem);
-	return rc;
+	return 0;
 }
 EXPORT_SYMBOL_GPL(cxllib_handle_fault);