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| author |   Jeremy Fitzhardinge <jeremy@goop.org> | 2007-05-02 19:27:15 +0200 |
|---|---|---|
| committer |   Andi Kleen <andi@basil.nowhere.org> | 2007-05-02 19:27:15 +0200 |
| commit | ce6234b5298902aaec831a67d5f8d9bd2ef5a488 (patch) | |
| tree | 939c22684e11a4f5f17abb89c4898f016e878e21 /arch/i386 | |
| parent | [PATCH] i386: PARAVIRT: revert map_pt_hook. (diff) | |
| download | linux-dev-ce6234b5298902aaec831a67d5f8d9bd2ef5a488.tar.xz linux-dev-ce6234b5298902aaec831a67d5f8d9bd2ef5a488.zip | |
[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 <jeremy@xensource.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Cc: Zachary Amsden <zach@vmware.com>
Diffstat (limited to 'arch/i386')
| -rw-r--r-- | arch/i386/kernel/paravirt.c | 5 | ||||
| -rw-r--r-- | arch/i386/mm/highmem.c | 9 |
2 files changed, 12 insertions, 2 deletions
diff --git a/arch/i386/kernel/paravirt.c b/arch/i386/kernel/paravirt.c index 13f41b5c887a..596f382c641c 100644 --- a/arch/i386/kernel/paravirt.c +++ b/arch/i386/kernel/paravirt.c @@ -20,6 +20,7 @@ #include <linux/efi.h> #include <linux/bcd.h> #include <linux/start_kernel.h> +#include <linux/highmem.h> #include <asm/bug.h> #include <asm/paravirt.h> @@ -316,6 +317,10 @@ struct paravirt_ops paravirt_ops = { .ptep_get_and_clear = native_ptep_get_and_clear, +#ifdef CONFIG_HIGHPTE + .kmap_atomic_pte = kmap_atomic, +#endif + #ifdef CONFIG_X86_PAE .set_pte_atomic = native_set_pte_atomic, .set_pte_present = native_set_pte_present, 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; |