From ce6234b5298902aaec831a67d5f8d9bd2ef5a488 Mon Sep 17 00:00:00 2001 From: Jeremy Fitzhardinge Date: Wed, 2 May 2007 19:27:15 +0200 Subject: [PATCH] i386: PARAVIRT: add kmap_atomic_pte for mapping highpte pages 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 Signed-off-by: Andi Kleen Cc: Zachary Amsden --- mm/highmem.c | 9 +++++++++ 1 file changed, 9 insertions(+) (limited to 'mm/highmem.c') diff --git a/mm/highmem.c b/mm/highmem.c index 51e1c1995fec..be8f8d36a8b9 100644 --- a/mm/highmem.c +++ b/mm/highmem.c @@ -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; -- cgit v1.2.3-59-g8ed1b