6 files changed, 100 insertions, 6 deletions

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index bfcb1a62a7b4..c87122dd790f 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1965,6 +1965,12 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
                                  or
                                  memmap=0x10000$0x18690000
 
+        memmap=nn[KMG]!ss[KMG]
+                        [KNL,X86] Mark specific memory as protected.
+                        Region of memory to be used, from ss to ss+nn.
+                        The memory region may be marked as e820 type 12 (0xc)
+                        and is NVDIMM or ADR memory.
+
         memory_corruption_check=0/1 [X86]
                         Some BIOSes seem to corrupt the first 64k of
                         memory when doing things like suspend/resume.
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index b7d31ca55187..9e3bcd6f4a48 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -1430,6 +1430,16 @@ 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 cdb1b70ddad0..971f18cd9ca0 100644
--- a/arch/x86/kernel/Makefile
+++ b/arch/x86/kernel/Makefile
@@ -94,6 +94,7 @@ 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 46201deee923..11cc7d54ec3f 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);