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[PATCH] i386: PARAVIRT: add kmap_atomic_pte for mapping highpte pages

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Xen and VMI both have special requirements when mapping a highmem pte
page into the kernel address space.  These can be dealt with by adding
a new kmap_atomic_pte() function for mapping highptes, and hooking it
into the paravirt_ops infrastructure.

Xen specifically wants to map the pte page RO, so this patch exposes a
helper function, kmap_atomic_prot, which maps the page with the
specified page protections.

This also adds a kmap_flush_unused() function to clear out the cached
kmap mappings.  Xen needs this to clear out any potential stray RW
mappings of pages which will become part of a pagetable.

[ Zach - vmi.c will need some attention after this patch.  It wasn't
  immediately obvious to me what needs to be done. ]

Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Cc: Zachary Amsden <zach@vmware.com>
This commit is contained in:
Jeremy Fitzhardinge
2007-05-02 19:27:15 +02:00
committed by Andi Kleen
parent a27fe809b8
commit ce6234b529
7 changed files with 50 additions and 4 deletions
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9
mm/highmem.c
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@@ -99,6 +99,15 @@ static void flush_all_zero_pkmaps(void)
flush_tlb_kernel_range(PKMAP_ADDR(0), PKMAP_ADDR(LAST_PKMAP));
}
/* Flush all unused kmap mappings in order to remove stray
mappings. */
void kmap_flush_unused(void)
{
spin_lock(&kmap_lock);
flush_all_zero_pkmaps();
spin_unlock(&kmap_lock);
}
static inline unsigned long map_new_virtual(struct page *page)
{
unsigned long vaddr;