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 --- arch/i386/mm/highmem.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) (limited to 'arch/i386/mm/highmem.c') diff --git a/arch/i386/mm/highmem.c b/arch/i386/mm/highmem.c index ac70d09df7ee..a1a21abf742e 100644 --- a/arch/i386/mm/highmem.c +++ b/arch/i386/mm/highmem.c @@ -26,7 +26,7 @@ void kunmap(struct page *page) * However when holding an atomic kmap is is not legal to sleep, so atomic * kmaps are appropriate for short, tight code paths only. */ -void *kmap_atomic(struct page *page, enum km_type type) +void *kmap_atomic_prot(struct page *page, enum km_type type, pgprot_t prot) { enum fixed_addresses idx; unsigned long vaddr; @@ -41,12 +41,17 @@ void *kmap_atomic(struct page *page, enum km_type type) return page_address(page); vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx); - set_pte(kmap_pte-idx, mk_pte(page, kmap_prot)); + set_pte(kmap_pte-idx, mk_pte(page, prot)); arch_flush_lazy_mmu_mode(); return (void*) vaddr; } +void *kmap_atomic(struct page *page, enum km_type type) +{ + return kmap_atomic_prot(page, type, kmap_prot); +} + void kunmap_atomic(void *kvaddr, enum km_type type) { unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK; -- cgit v1.2.2