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Subject[PATCH 01/21] e820, efi: add ACPI 6.0 persistent memory types
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Date
ACPI 6.0 formalizes e820-type-7 and efi-type-14 as persistent memory.
Mark it "reserved" and allow it to be claimed by a persistent memory
device driver.

This definition is in addition to the Linux kernel's existing type-12
definition that was recently added in support of shipping platforms with
NVDIMM support that predate ACPI 6.0 (which now classifies type-12 as
OEM reserved). We may choose to exploit this wealth of definitions for
NVDIMMs to differentiate E820_PRAM (type-12) from E820_PMEM (type-7).
One potential differentiation is that PMEM is not backed by struct page
by default in contrast to PRAM. For now, they are effectively treated
as aliases by the mm.

Note, /proc/iomem can be consulted for differentiating legacy
"Persistent RAM" E820_PRAM vs standard "Persistent I/O Memory"
E820_PMEM.

Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Boaz Harrosh <boaz@plexistor.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jens Axboe <axboe@fb.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com>
---
arch/arm64/kernel/efi.c | 1 +
arch/ia64/kernel/efi.c | 1 +
arch/x86/boot/compressed/eboot.c | 4 ++++
arch/x86/include/uapi/asm/e820.h | 1 +
arch/x86/kernel/e820.c | 25 +++++++++++++++++++------
arch/x86/platform/efi/efi.c | 3 +++
include/linux/efi.h | 3 ++-
7 files changed, 31 insertions(+), 7 deletions(-)

diff --git a/arch/arm64/kernel/efi.c b/arch/arm64/kernel/efi.c
index ab21e0d58278..9d4aa18f2a82 100644
--- a/arch/arm64/kernel/efi.c
+++ b/arch/arm64/kernel/efi.c
@@ -158,6 +158,7 @@ static __init int is_reserve_region(efi_memory_desc_t *md)
case EFI_BOOT_SERVICES_CODE:
case EFI_BOOT_SERVICES_DATA:
case EFI_CONVENTIONAL_MEMORY:
+ case EFI_PERSISTENT_MEMORY:
return 0;
default:
break;
diff --git a/arch/ia64/kernel/efi.c b/arch/ia64/kernel/efi.c
index c52d7540dc05..cd8b7485e396 100644
--- a/arch/ia64/kernel/efi.c
+++ b/arch/ia64/kernel/efi.c
@@ -1227,6 +1227,7 @@ efi_initialize_iomem_resources(struct resource *code_resource,
case EFI_RUNTIME_SERVICES_CODE:
case EFI_RUNTIME_SERVICES_DATA:
case EFI_ACPI_RECLAIM_MEMORY:
+ case EFI_PERSISTENT_MEMORY:
default:
name = "reserved";
break;
diff --git a/arch/x86/boot/compressed/eboot.c b/arch/x86/boot/compressed/eboot.c
index ef17683484e9..dde5bf7726f4 100644
--- a/arch/x86/boot/compressed/eboot.c
+++ b/arch/x86/boot/compressed/eboot.c
@@ -1222,6 +1222,10 @@ static efi_status_t setup_e820(struct boot_params *params,
e820_type = E820_NVS;
break;

+ case EFI_PERSISTENT_MEMORY:
+ e820_type = E820_PMEM;
+ break;
+
default:
continue;
}
diff --git a/arch/x86/include/uapi/asm/e820.h b/arch/x86/include/uapi/asm/e820.h
index 960a8a9dc4ab..0f457e6eab18 100644
--- a/arch/x86/include/uapi/asm/e820.h
+++ b/arch/x86/include/uapi/asm/e820.h
@@ -32,6 +32,7 @@
#define E820_ACPI 3
#define E820_NVS 4
#define E820_UNUSABLE 5
+#define E820_PMEM 7

/*
* This is a non-standardized way to represent ADR or NVDIMM regions that
diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c
index 11cc7d54ec3f..410af501a941 100644
--- a/arch/x86/kernel/e820.c
+++ b/arch/x86/kernel/e820.c
@@ -137,6 +137,8 @@ static void __init e820_print_type(u32 type)
case E820_RESERVED_KERN:
printk(KERN_CONT "usable");
break;
+ case E820_PMEM:
+ case E820_PRAM:
case E820_RESERVED:
printk(KERN_CONT "reserved");
break;
@@ -149,9 +151,6 @@ 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;
@@ -919,10 +918,26 @@ static inline const char *e820_type_to_string(int e820_type)
case E820_NVS: return "ACPI Non-volatile Storage";
case E820_UNUSABLE: return "Unusable memory";
case E820_PRAM: return "Persistent RAM";
+ case E820_PMEM: return "Persistent I/O Memory";
default: return "reserved";
}
}

+static bool do_mark_busy(u32 type, struct resource *res)
+{
+ if (res->start < (1ULL<<20))
+ return true;
+
+ switch (type) {
+ case E820_RESERVED:
+ case E820_PRAM:
+ case E820_PMEM:
+ return false;
+ default:
+ return true;
+ }
+}
+
/*
* Mark e820 reserved areas as busy for the resource manager.
*/
@@ -952,9 +967,7 @@ 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) &&
- (e820.map[i].type != E820_PRAM)) ||
- res->start < (1ULL<<20)) {
+ if (do_mark_busy(e820.map[i].type, res)) {
res->flags |= IORESOURCE_BUSY;
insert_resource(&iomem_resource, res);
}
diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c
index dbc8627a5cdf..a116e236ac3f 100644
--- a/arch/x86/platform/efi/efi.c
+++ b/arch/x86/platform/efi/efi.c
@@ -145,6 +145,9 @@ static void __init do_add_efi_memmap(void)
case EFI_UNUSABLE_MEMORY:
e820_type = E820_UNUSABLE;
break;
+ case EFI_PERSISTENT_MEMORY:
+ e820_type = E820_PMEM;
+ break;
default:
/*
* EFI_RESERVED_TYPE EFI_RUNTIME_SERVICES_CODE
diff --git a/include/linux/efi.h b/include/linux/efi.h
index cf7e431cbc73..28868504aa17 100644
--- a/include/linux/efi.h
+++ b/include/linux/efi.h
@@ -85,7 +85,8 @@ typedef struct {
#define EFI_MEMORY_MAPPED_IO 11
#define EFI_MEMORY_MAPPED_IO_PORT_SPACE 12
#define EFI_PAL_CODE 13
-#define EFI_MAX_MEMORY_TYPE 14
+#define EFI_PERSISTENT_MEMORY 14
+#define EFI_MAX_MEMORY_TYPE 15

/* Attribute values: */
#define EFI_MEMORY_UC ((u64)0x0000000000000001ULL) /* uncached */


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