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[PATCH] x86: make __FIXADDR_TOP variable to allow it to make space for a hypervisor

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Make __FIXADDR_TOP a variable, so that it can be set to not get in the way of
address space a hypervisor may want to reserve.

Original patch by Gerd Hoffmann <kraxel@suse.de>

Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
Cc: Gerd Hoffmann <kraxel@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Jeremy Fitzhardinge
2006-09-25 23:32:25 -07:00
committed by Linus Torvalds
parent 9f093394d7
commit 052e79941a
4 changed files with 75 additions and 1 deletions
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26
arch/i386/mm/pgtable.c
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@@ -12,6 +12,7 @@
#include <linux/slab.h>
#include <linux/pagemap.h>
#include <linux/spinlock.h>
#include <linux/module.h>
#include <asm/system.h>
#include <asm/pgtable.h>
@@ -139,6 +140,12 @@ void set_pmd_pfn(unsigned long vaddr, unsigned long pfn, pgprot_t flags)
__flush_tlb_one(vaddr);
}
static int fixmaps;
#ifndef CONFIG_COMPAT_VDSO
unsigned long __FIXADDR_TOP = 0xfffff000;
EXPORT_SYMBOL(__FIXADDR_TOP);
#endif
void __set_fixmap (enum fixed_addresses idx, unsigned long phys, pgprot_t flags)
{
unsigned long address = __fix_to_virt(idx);
@@ -148,6 +155,25 @@ void __set_fixmap (enum fixed_addresses idx, unsigned long phys, pgprot_t flags)
return;
}
set_pte_pfn(address, phys >> PAGE_SHIFT, flags);
fixmaps++;
}
/**
* reserve_top_address - reserves a hole in the top of kernel address space
* @reserve - size of hole to reserve
*
* Can be used to relocate the fixmap area and poke a hole in the top
* of kernel address space to make room for a hypervisor.
*/
void reserve_top_address(unsigned long reserve)
{
BUG_ON(fixmaps > 0);
#ifdef CONFIG_COMPAT_VDSO
BUG_ON(reserve != 0);
#else
__FIXADDR_TOP = -reserve - PAGE_SIZE;
__VMALLOC_RESERVE += reserve;
#endif
}
pte_t *pte_alloc_one_kernel(struct mm_struct *mm, unsigned long address)