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Commit ec776ef6 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Ingo Molnar
Browse files

x86/mm: Add support for the non-standard protected e820 type 



Various recent BIOSes support NVDIMMs or ADR using a
non-standard e820 memory type, and Intel supplied reference
Linux code using this type to various vendors.

Wire this e820 table type up to export platform devices for the
pmem driver so that we can use it in Linux.

Based on earlier work from:

   Dave Jiang <dave.jiang@intel.com>
   Dan Williams <dan.j.williams@intel.com>

Includes fixes for NUMA regions from Boaz Harrosh.

Tested-by: default avatarRoss Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Acked-by: default avatarDan Williams <dan.j.williams@intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Boaz Harrosh <boaz@plexistor.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jens Axboe <axboe@fb.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Keith Busch <keith.busch@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matthew Wilcox <willy@linux.intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-nvdimm@ml01.01.org
Link: http://lkml.kernel.org/r/1427872339-6688-2-git-send-email-hch@lst.de


[ Minor cleanups. ]
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent e42391cd

Documentation/kernel-parameters.txt

+6 −0
Original line number Diff line number Diff line
@@ -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.

arch/x86/Kconfig

+10 −0
Original line number Diff line number Diff line
@@ -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

arch/x86/include/uapi/asm/e820.h

+10 −0
Original line number Diff line number Diff line
@@ -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

arch/x86/kernel/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -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

arch/x86/kernel/e820.c

+20 −6
Original line number Diff line number Diff line
@@ -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);

		}