x86: 46 bit physical address support on 64 bits

Extend the maximum addressable memory on x86-64 from 2^44 to
2^46 bytes. This requires some shuffling around of the vmalloc
and virtual memmap memory areas, to keep them away from the
direct mapping of up to 64TB of physical memory.

This patch also introduces a guard hole between the vmalloc
area and the virtual memory map space.  There's really no
good reason why we wouldn't have a guard hole there.

[ Impact: future hardware enablement ]

Signed-off-by: Rik van Riel <riel@redhat.com>
LKML-Reference: <20090505172856.6820db22@cuia.bos.redhat.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>

4 files changed, 11 insertions, 10 deletions

diff --git a/Documentation/x86/x86_64/mm.txt b/Documentation/x86/x86_64/mm.txt
index 29b52b14d0b4..539413235845 100644
--- a/Documentation/x86/x86_64/mm.txt
+++ b/Documentation/x86/x86_64/mm.txt
@@ -6,10 +6,11 @@ Virtual memory map with 4 level page tables:
 0000000000000000 - 00007fffffffffff (=47 bits) user space, different per mm
 hole caused by [48:63] sign extension
 ffff800000000000 - ffff80ffffffffff (=40 bits) guard hole
-ffff880000000000 - ffffc0ffffffffff (=57 TB) direct mapping of all phys. memory
-ffffc10000000000 - ffffc1ffffffffff (=40 bits) hole
-ffffc20000000000 - ffffe1ffffffffff (=45 bits) vmalloc/ioremap space
-ffffe20000000000 - ffffe2ffffffffff (=40 bits) virtual memory map (1TB)
+ffff880000000000 - ffffc8ffffffffff (=64 TB) direct mapping of all phys. memory
+ffffc80000000000 - ffffc8ffffffffff (=40 bits) hole
+ffffc90000000000 - ffffe8ffffffffff (=45 bits) vmalloc/ioremap space
+ffffe90000000000 - ffffe9ffffffffff (=40 bits) hole
+ffffea0000000000 - ffffeaffffffffff (=40 bits) virtual memory map (1TB)
 ... unused hole ...
 ffffffff80000000 - ffffffffa0000000 (=512 MB)  kernel text mapping, from phys 0
 ffffffffa0000000 - fffffffffff00000 (=1536 MB) module mapping space
diff --git a/arch/x86/include/asm/page_64_types.h b/arch/x86/include/asm/page_64_types.h
index 3f587188ae68..6fadb020bd2b 100644
--- a/arch/x86/include/asm/page_64_types.h
+++ b/arch/x86/include/asm/page_64_types.h
@@ -47,7 +47,7 @@
 #define __START_KERNEL          (__START_KERNEL_map + __PHYSICAL_START)
 #define __START_KERNEL_map      _AC(0xffffffff80000000, UL)
 
-/* See Documentation/x86_64/mm.txt for a description of the memory map. */
+/* See Documentation/x86/x86_64/mm.txt for a description of the memory map. */
 #define __PHYSICAL_MASK_SHIFT   46
 #define __VIRTUAL_MASK_SHIFT    48
 
diff --git a/arch/x86/include/asm/pgtable_64_types.h b/arch/x86/include/asm/pgtable_64_types.h
index fbf42b8e0383..766ea16fbbbd 100644
--- a/arch/x86/include/asm/pgtable_64_types.h
+++ b/arch/x86/include/asm/pgtable_64_types.h
@@ -51,11 +51,11 @@ typedef struct { pteval_t pte; } pte_t;
 #define PGDIR_SIZE      (_AC(1, UL) << PGDIR_SHIFT)
 #define PGDIR_MASK      (~(PGDIR_SIZE - 1))
 
-
+/* See Documentation/x86/x86_64/mm.txt for a description of the memory map. */
 #define MAXMEM           _AC(__AC(1, UL) << MAX_PHYSMEM_BITS, UL)
-#define VMALLOC_START    _AC(0xffffc20000000000, UL)
-#define VMALLOC_END      _AC(0xffffe1ffffffffff, UL)
-#define VMEMMAP_START    _AC(0xffffe20000000000, UL)
+#define VMALLOC_START    _AC(0xffffc90000000000, UL)
+#define VMALLOC_END      _AC(0xffffe8ffffffffff, UL)
+#define VMEMMAP_START    _AC(0xffffea0000000000, UL)
 #define MODULES_VADDR    _AC(0xffffffffa0000000, UL)
 #define MODULES_END      _AC(0xffffffffff000000, UL)
 #define MODULES_LEN   (MODULES_END - MODULES_VADDR)
diff --git a/arch/x86/include/asm/sparsemem.h b/arch/x86/include/asm/sparsemem.h
index e3cc3c063ec5..4517d6b93188 100644
--- a/arch/x86/include/asm/sparsemem.h
+++ b/arch/x86/include/asm/sparsemem.h
@@ -27,7 +27,7 @@
 #else /* CONFIG_X86_32 */
 # define SECTION_SIZE_BITS      27 /* matt - 128 is convenient right now */
 # define MAX_PHYSADDR_BITS      44
-# define MAX_PHYSMEM_BITS       44 /* Can be max 45 bits */
+# define MAX_PHYSMEM_BITS       46
 #endif
 
 #endif /* CONFIG_SPARSEMEM */