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Commit c898faf9 authored by Rik van Riel's avatar Rik van Riel Committed by H. Peter Anvin
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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: default avatarRik van Riel <riel@redhat.com>
LKML-Reference: <20090505172856.6820db22@cuia.bos.redhat.com>
Signed-off-by: default avatarH. Peter Anvin <hpa@zytor.com>
parent a454ab31

Documentation/x86/x86_64/mm.txt

+5 −4
Original line number Diff line number Diff line
@@ -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

arch/x86/include/asm/page_64_types.h

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

arch/x86/include/asm/pgtable_64_types.h

+4 −4
Original line number Diff line number Diff line
@@ -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)

arch/x86/include/asm/sparsemem.h

+1 −1
Original line number Diff line number Diff line
@@ -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 */