Merge tag 'powerpc-4.19-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux

Pull powerpc updates from Michael Ellerman:
 "Notable changes:

   - A fix for a bug in our page table fragment allocator, where a page
     table page could be freed and reallocated for something else while
     still in use, leading to memory corruption etc. The fix reuses
     pt_mm in struct page (x86 only) for a powerpc only refcount.

   - Fixes to our pkey support. Several are user-visible changes, but
     bring us in to line with x86 behaviour and/or fix outright bugs.
     Thanks to Florian Weimer for reporting many of these.

   - A series to improve the hvc driver & related OPAL console code,
     which have been seen to cause hardlockups at times. The hvc driver
     changes in particular have been in linux-next for ~month.

   - Increase our MAX_PHYSMEM_BITS to 128TB when SPARSEMEM_VMEMMAP=y.

   - Remove Power8 DD1 and Power9 DD1 support, neither chip should be in
     use anywhere other than as a paper weight.

   - An optimised memcmp implementation using Power7-or-later VMX
     instructions

   - Support for barrier_nospec on some NXP CPUs.

   - Support for flushing the count cache on context switch on some IBM
     CPUs (controlled by firmware), as a Spectre v2 mitigation.

   - A series to enhance the information we print on unhandled signals
     to bring it into line with other arches, including showing the
     offending VMA and dumping the instructions around the fault.

  Thanks to: Aaro Koskinen, Akshay Adiga, Alastair D'Silva, Alexey
  Kardashevskiy, Alexey Spirkov, Alistair Popple, Andrew Donnellan,
  Aneesh Kumar K.V, Anju T Sudhakar, Arnd Bergmann, Bartosz Golaszewski,
  Benjamin Herrenschmidt, Bharat Bhushan, Bjoern Noetel, Boqun Feng,
  Breno Leitao, Bryant G. Ly, Camelia Groza, Christophe Leroy, Christoph
  Hellwig, Cyril Bur, Dan Carpenter, Daniel Klamt, Darren Stevens, Dave
  Young, David Gibson, Diana Craciun, Finn Thain, Florian Weimer,
  Frederic Barrat, Gautham R. Shenoy, Geert Uytterhoeven, Geoff Levand,
  Guenter Roeck, Gustavo Romero, Haren Myneni, Hari Bathini, Joel
  Stanley, Jonathan Neuschäfer, Kees Cook, Madhavan Srinivasan, Mahesh
  Salgaonkar, Markus Elfring, Mathieu Malaterre, Mauro S. M. Rodrigues,
  Michael Hanselmann, Michael Neuling, Michael Schmitz, Mukesh Ojha,
  Murilo Opsfelder Araujo, Nicholas Piggin, Parth Y Shah, Paul
  Mackerras, Paul Menzel, Ram Pai, Randy Dunlap, Rashmica Gupta, Reza
  Arbab, Rodrigo R. Galvao, Russell Currey, Sam Bobroff, Scott Wood,
  Shilpasri G Bhat, Simon Guo, Souptick Joarder, Stan Johnson, Thiago
  Jung Bauermann, Tyrel Datwyler, Vaibhav Jain, Vasant Hegde, Venkat
  Rao, zhong jiang"

* tag 'powerpc-4.19-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (234 commits)
  powerpc/mm/book3s/radix: Add mapping statistics
  powerpc/uaccess: Enable get_user(u64, *p) on 32-bit
  powerpc/mm/hash: Remove unnecessary do { } while(0) loop
  powerpc/64s: move machine check SLB flushing to mm/slb.c
  powerpc/powernv/idle: Fix build error
  powerpc/mm/tlbflush: update the mmu_gather page size while iterating address range
  powerpc/mm: remove warning about ‘type’ being set
  powerpc/32: Include setup.h header file to fix warnings
  powerpc: Move `path` variable inside DEBUG_PROM
  powerpc/powermac: Make some functions static
  powerpc/powermac: Remove variable x that's never read
  cxl: remove a dead branch
  powerpc/powermac: Add missing include of header pmac.h
  powerpc/kexec: Use common error handling code in setup_new_fdt()
  powerpc/xmon: Add address lookup for percpu symbols
  powerpc/mm: remove huge_pte_offset_and_shift() prototype
  powerpc/lib: Use patch_site to patch copy_32 functions once cache is enabled
  powerpc/pseries: Fix endianness while restoring of r3 in MCE handler.
  powerpc/fadump: merge adjacent memory ranges to reduce PT_LOAD segements
  powerpc/fadump: handle crash memory ranges array index overflow
  ...

1 files changed, 85 insertions, 36 deletions

diff --git a/arch/powerpc/platforms/powernv/memtrace.c b/arch/powerpc/platforms/powernv/memtrace.c
index b99283df8584..51dc398ae3f7 100644
--- a/arch/powerpc/platforms/powernv/memtrace.c
+++ b/arch/powerpc/platforms/powernv/memtrace.c
@@ -47,38 +47,9 @@ static ssize_t memtrace_read(struct file *filp, char __user *ubuf,
 	return simple_read_from_buffer(ubuf, count, ppos, ent->mem, ent->size);
 }
 
-static bool valid_memtrace_range(struct memtrace_entry *dev,
-				 unsigned long start, unsigned long size)
-{
-	if ((start >= dev->start) &&
-	    ((start + size) <= (dev->start + dev->size)))
-		return true;
-
-	return false;
-}
-
-static int memtrace_mmap(struct file *filp, struct vm_area_struct *vma)
-{
-	unsigned long size = vma->vm_end - vma->vm_start;
-	struct memtrace_entry *dev = filp->private_data;
-
-	if (!valid_memtrace_range(dev, vma->vm_pgoff << PAGE_SHIFT, size))
-		return -EINVAL;
-
-	vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
-
-	if (remap_pfn_range(vma, vma->vm_start,
-			    vma->vm_pgoff + (dev->start >> PAGE_SHIFT),
-			    size, vma->vm_page_prot))
-		return -EAGAIN;
-
-	return 0;
-}
-
 static const struct file_operations memtrace_fops = {
 	.llseek = default_llseek,
 	.read	= memtrace_read,
-	.mmap	= memtrace_mmap,
 	.open	= simple_open,
 };
 
@@ -206,8 +177,11 @@ static int memtrace_init_debugfs(void)
 
 		snprintf(ent->name, 16, "%08x", ent->nid);
 		dir = debugfs_create_dir(ent->name, memtrace_debugfs_dir);
-		if (!dir)
+		if (!dir) {
+			pr_err("Failed to create debugfs directory for node %d\n",
+				ent->nid);
 			return -1;
+		}
 
 		ent->dir = dir;
 		debugfs_create_file("trace", 0400, dir, ent, &memtrace_fops);
@@ -218,18 +192,93 @@ static int memtrace_init_debugfs(void)
 	return ret;
 }
 
+static int online_mem_block(struct memory_block *mem, void *arg)
+{
+	return device_online(&mem->dev);
+}
+
+/*
+ * Iterate through the chunks of memory we have removed from the kernel
+ * and attempt to add them back to the kernel.
+ */
+static int memtrace_online(void)
+{
+	int i, ret = 0;
+	struct memtrace_entry *ent;
+
+	for (i = memtrace_array_nr - 1; i >= 0; i--) {
+		ent = &memtrace_array[i];
+
+		/* We have onlined this chunk previously */
+		if (ent->nid == -1)
+			continue;
+
+		/* Remove from io mappings */
+		if (ent->mem) {
+			iounmap(ent->mem);
+			ent->mem = 0;
+		}
+
+		if (add_memory(ent->nid, ent->start, ent->size)) {
+			pr_err("Failed to add trace memory to node %d\n",
+				ent->nid);
+			ret += 1;
+			continue;
+		}
+
+		/*
+		 * If kernel isn't compiled with the auto online option
+		 * we need to online the memory ourselves.
+		 */
+		if (!memhp_auto_online) {
+			walk_memory_range(PFN_DOWN(ent->start),
+					  PFN_UP(ent->start + ent->size - 1),
+					  NULL, online_mem_block);
+		}
+
+		/*
+		 * Memory was added successfully so clean up references to it
+		 * so on reentry we can tell that this chunk was added.
+		 */
+		debugfs_remove_recursive(ent->dir);
+		pr_info("Added trace memory back to node %d\n", ent->nid);
+		ent->size = ent->start = ent->nid = -1;
+	}
+	if (ret)
+		return ret;
+
+	/* If all chunks of memory were added successfully, reset globals */
+	kfree(memtrace_array);
+	memtrace_array = NULL;
+	memtrace_size = 0;
+	memtrace_array_nr = 0;
+	return 0;
+}
+
 static int memtrace_enable_set(void *data, u64 val)
 {
-	if (memtrace_size)
+	u64 bytes;
+
+	/*
+	 * Don't attempt to do anything if size isn't aligned to a memory
+	 * block or equal to zero.
+	 */
+	bytes = memory_block_size_bytes();
+	if (val & (bytes - 1)) {
+		pr_err("Value must be aligned with 0x%llx\n", bytes);
 		return -EINVAL;
+	}
 
-	if (!val)
-		return -EINVAL;
+	/* Re-add/online previously removed/offlined memory */
+	if (memtrace_size) {
+		if (memtrace_online())
+			return -EAGAIN;
+	}
 
-	/* Make sure size is aligned to a memory block */
-	if (val & (memory_block_size_bytes() - 1))
-		return -EINVAL;
+	if (!val)
+		return 0;
 
+	/* Offline and remove memory */
 	if (memtrace_init_regions_runtime(val))
 		return -EINVAL;