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| author | Eduardo Habkost <ehabkost@redhat.com> | 2008-06-25 00:19:16 -0400 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2008-07-08 13:11:04 +0200 |
| commit | a6523748bddd38bcec11431f57502090b6014a96 (patch) | |
| tree | 1aa906ba270628323fcdfb26a0ae0f7cfba80ae6 /include/asm-x86/page_64.h | |
| parent | 491eccb721c2ee67250273a96e4515fb5b423337 (diff) | |
| download | blackbird-op-linux-a6523748bddd38bcec11431f57502090b6014a96.tar.gz blackbird-op-linux-a6523748bddd38bcec11431f57502090b6014a96.zip | |
paravirt/x86, 64-bit: move __PAGE_OFFSET to leave a space for hypervisor
Set __PAGE_OFFSET to the most negative possible address +
16*PGDIR_SIZE. The gap is to allow a space for a hypervisor to fit.
The gap is more or less arbitrary, but it's what Xen needs.
When booting native, kernel/head_64.S has a set of compile-time
generated pagetables used at boot time. This patch removes their
absolutely hard-coded layout, and makes it parameterised on
__PAGE_OFFSET (and __START_KERNEL_map).
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: xen-devel <xen-devel@lists.xensource.com>
Cc: Stephen Tweedie <sct@redhat.com>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Cc: Mark McLoughlin <markmc@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'include/asm-x86/page_64.h')
| -rw-r--r-- | include/asm-x86/page_64.h | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/include/asm-x86/page_64.h b/include/asm-x86/page_64.h index cac5b9e78265..010d12db80dc 100644 --- a/include/asm-x86/page_64.h +++ b/include/asm-x86/page_64.h @@ -26,7 +26,13 @@ #define PUD_PAGE_SIZE (_AC(1, UL) << PUD_SHIFT) #define PUD_PAGE_MASK (~(PUD_PAGE_SIZE-1)) -#define __PAGE_OFFSET _AC(0xffff810000000000, UL) +/* + * Set __PAGE_OFFSET to the most negative possible address + + * PGDIR_SIZE*16 (pgd slot 272). The gap is to allow a space for a + * hypervisor to fit. Choosing 16 slots here is arbitrary, but it's + * what Xen requires. + */ +#define __PAGE_OFFSET _AC(0xffff880000000000, UL) #define __PHYSICAL_START CONFIG_PHYSICAL_START #define __KERNEL_ALIGN 0x200000 |
