Merge branch 'x86-pmem-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull PMEM driver from Ingo Molnar:
 "This is the initial support for the pmem block device driver:
  persistent non-volatile memory space mapped into the system's physical
  memory space as large physical memory regions.

  The driver is based on Intel code, written by Ross Zwisler, with fixes
  by Boaz Harrosh, integrated with x86 e820 memory resource management
  and tidied up by Christoph Hellwig.

  Note that there were two other separate pmem driver submissions to
  lkml: but apparently all parties (Ross Zwisler, Boaz Harrosh) are
  reasonably happy with this initial version.

  This version enables minimal support that enables persistent memory
  devices out in the wild to work as block devices, identified through a
  magic (non-standard) e820 flag and auto-discovered if
  CONFIG_X86_PMEM_LEGACY=y, or added explicitly through manipulating the
  memory maps via the "memmap=..." boot option with the new, special '!'
  modifier character.

  Limitations: this is a regular block device, and since the pmem areas
  are not struct page backed, they are invisible to the rest of the
  system (other than the block IO device), so direct IO to/from pmem
  areas, direct mmap() or XIP is not possible yet.  The page cache will
  also shadow and double buffer pmem contents, etc.

  Initial support is for x86"

* 'x86-pmem-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  drivers/block/pmem: Fix 32-bit build warning in pmem_alloc()
  drivers/block/pmem: Add a driver for persistent memory
  x86/mm: Add support for the non-standard protected e820 type

5 files changed, 94 insertions, 6 deletions

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 937812b8e0b9..6049d587599e 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -1421,6 +1421,16 @@ config ILLEGAL_POINTER_VALUE
 
 source "mm/Kconfig"
 
+config X86_PMEM_LEGACY
+        bool "Support non-standard NVDIMMs and ADR protected memory"
+        help
+          Treat memory marked using the non-standard e820 type of 12 as used
+          by the Intel Sandy Bridge-EP reference BIOS as protected memory.
+          The kernel will offer these regions to the 'pmem' driver so
+          they can be used for persistent storage.
+
+          Say Y if unsure.
+
 config HIGHPTE
         bool "Allocate 3rd-level pagetables from highmem"
         depends on HIGHMEM
diff --git a/arch/x86/include/uapi/asm/e820.h b/arch/x86/include/uapi/asm/e820.h
index d993e33f5236..960a8a9dc4ab 100644
--- a/arch/x86/include/uapi/asm/e820.h
+++ b/arch/x86/include/uapi/asm/e820.h
@@ -33,6 +33,16 @@
 #define E820_NVS        4
 #define E820_UNUSABLE   5
 
+/*
+ * This is a non-standardized way to represent ADR or NVDIMM regions that
+ * persist over a reboot.  The kernel will ignore their special capabilities
+ * unless the CONFIG_X86_PMEM_LEGACY=y option is set.
+ *
+ * ( Note that older platforms also used 6 for the same type of memory,
+ *   but newer versions switched to 12 as 6 was assigned differently.  Some
+ *   time they will learn... )
+ */
+#define E820_PRAM       12
 
 /*
  * reserved RAM used by kernel itself
diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
index c887cd944f0c..9bcd0b56ca17 100644
--- a/arch/x86/kernel/Makefile
+++ b/arch/x86/kernel/Makefile
@@ -95,6 +95,7 @@ obj-$(CONFIG_KVM_GUEST)		+= kvm.o kvmclock.o
 obj-$(CONFIG_PARAVIRT)          += paravirt.o paravirt_patch_$(BITS).o
 obj-$(CONFIG_PARAVIRT_SPINLOCKS)+= paravirt-spinlocks.o
 obj-$(CONFIG_PARAVIRT_CLOCK)    += pvclock.o
+obj-$(CONFIG_X86_PMEM_LEGACY)   += pmem.o
 
 obj-$(CONFIG_PCSPKR_PLATFORM)   += pcspeaker.o
 
diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c
index 7d46bb260334..e2ce85db2283 100644
--- a/arch/x86/kernel/e820.c
+++ b/arch/x86/kernel/e820.c
@@ -149,6 +149,9 @@ static void __init e820_print_type(u32 type)
         case E820_UNUSABLE:
                 printk(KERN_CONT "unusable");
                 break;
+        case E820_PRAM:
+                printk(KERN_CONT "persistent (type %u)", type);
+                break;
         default:
                 printk(KERN_CONT "type %u", type);
                 break;
@@ -343,7 +346,7 @@ int __init sanitize_e820_map(struct e820entry *biosmap, int max_nr_map,
                  * continue building up new bios map based on this
                  * information
                  */
-                if (current_type != last_type)  {
+                if (current_type != last_type || current_type == E820_PRAM) {
                         if (last_type != 0)      {
                                 new_bios[new_bios_entry].size =
                                         change_point[chgidx]->addr - last_addr;
@@ -688,6 +691,7 @@ void __init e820_mark_nosave_regions(unsigned long limit_pfn)
                         register_nosave_region(pfn, PFN_UP(ei->addr));
 
                 pfn = PFN_DOWN(ei->addr + ei->size);
+
                 if (ei->type != E820_RAM && ei->type != E820_RESERVED_KERN)
                         register_nosave_region(PFN_UP(ei->addr), pfn);
 
@@ -748,7 +752,7 @@ u64 __init early_reserve_e820(u64 size, u64 align)
 /*
  * Find the highest page frame number we have available
  */
-static unsigned long __init e820_end_pfn(unsigned long limit_pfn, unsigned type)
+static unsigned long __init e820_end_pfn(unsigned long limit_pfn)
 {
         int i;
         unsigned long last_pfn = 0;
@@ -759,7 +763,11 @@ static unsigned long __init e820_end_pfn(unsigned long limit_pfn, unsigned type)
                 unsigned long start_pfn;
                 unsigned long end_pfn;
 
-                if (ei->type != type)
+                /*
+                 * Persistent memory is accounted as ram for purposes of
+                 * establishing max_pfn and mem_map.
+                 */
+                if (ei->type != E820_RAM && ei->type != E820_PRAM)
                         continue;
 
                 start_pfn = ei->addr >> PAGE_SHIFT;
@@ -784,12 +792,12 @@ static unsigned long __init e820_end_pfn(unsigned long limit_pfn, unsigned type)
 }
 unsigned long __init e820_end_of_ram_pfn(void)
 {
-        return e820_end_pfn(MAX_ARCH_PFN, E820_RAM);
+        return e820_end_pfn(MAX_ARCH_PFN);
 }
 
 unsigned long __init e820_end_of_low_ram_pfn(void)
 {
-        return e820_end_pfn(1UL<<(32 - PAGE_SHIFT), E820_RAM);
+        return e820_end_pfn(1UL << (32-PAGE_SHIFT));
 }
 
 static void early_panic(char *msg)
@@ -866,6 +874,9 @@ static int __init parse_memmap_one(char *p)
         } else if (*p == '$') {
                 start_at = memparse(p+1, &p);
                 e820_add_region(start_at, mem_size, E820_RESERVED);
+        } else if (*p == '!') {
+                start_at = memparse(p+1, &p);
+                e820_add_region(start_at, mem_size, E820_PRAM);
         } else
                 e820_remove_range(mem_size, ULLONG_MAX - mem_size, E820_RAM, 1);
 
@@ -907,6 +918,7 @@ static inline const char *e820_type_to_string(int e820_type)
         case E820_ACPI: return "ACPI Tables";
         case E820_NVS:  return "ACPI Non-volatile Storage";
         case E820_UNUSABLE:     return "Unusable memory";
+        case E820_PRAM: return "Persistent RAM";
         default:        return "reserved";
         }
 }
@@ -940,7 +952,9 @@ void __init e820_reserve_resources(void)
                  * pci device BAR resource and insert them later in
                  * pcibios_resource_survey()
                  */
-                if (e820.map[i].type != E820_RESERVED || res->start < (1ULL<<20)) {
+                if (((e820.map[i].type != E820_RESERVED) &&
+                     (e820.map[i].type != E820_PRAM)) ||
+                     res->start < (1ULL<<20)) {
                         res->flags |= IORESOURCE_BUSY;
                         insert_resource(&iomem_resource, res);
                 }
diff --git a/arch/x86/kernel/pmem.c b/arch/x86/kernel/pmem.c
new file mode 100644
index 000000000000..3420c874ddc5
--- /dev/null
+++ b/arch/x86/kernel/pmem.c
@@ -0,0 +1,53 @@
+/*
+ * Copyright (c) 2015, Christoph Hellwig.
+ */
+#include <linux/memblock.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <asm/e820.h>
+#include <asm/page_types.h>
+#include <asm/setup.h>
+
+static __init void register_pmem_device(struct resource *res)
+{
+        struct platform_device *pdev;
+        int error;
+
+        pdev = platform_device_alloc("pmem", PLATFORM_DEVID_AUTO);
+        if (!pdev)
+                return;
+
+        error = platform_device_add_resources(pdev, res, 1);
+        if (error)
+                goto out_put_pdev;
+
+        error = platform_device_add(pdev);
+        if (error)
+                goto out_put_pdev;
+        return;
+
+out_put_pdev:
+        dev_warn(&pdev->dev, "failed to add 'pmem' (persistent memory) device!\n");
+        platform_device_put(pdev);
+}
+
+static __init int register_pmem_devices(void)
+{
+        int i;
+
+        for (i = 0; i < e820.nr_map; i++) {
+                struct e820entry *ei = &e820.map[i];
+
+                if (ei->type == E820_PRAM) {
+                        struct resource res = {
+                                .flags  = IORESOURCE_MEM,
+                                .start  = ei->addr,
+                                .end    = ei->addr + ei->size - 1,
+                        };
+                        register_pmem_device(&res);
+                }
+        }
+
+        return 0;
+}
+device_initcall(register_pmem_devices);