From: Benjamin Herrenschmidt Date: Fri, 21 Oct 2005 04:12:51 +0000 (+1000) Subject: [PATCH] ppc64: Fix pages marked dirty abusively X-Git-Tag: v2.6.14~53 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=5d96551541a8f5521dcc8c634a18d42a3d349ec9;p=linux-2.6 [PATCH] ppc64: Fix pages marked dirty abusively While working on 64K pages, I found this little buglet in our update_mmu_cache() implementation. The code calls __hash_page() passing it an "access" parameter (the type of access that triggers the hash) containing the bits _PAGE_RW and _PAGE_USER of the linux PTE. The latter is useless in this case and the former is wrong. In fact, if we have a writeable PTE and we pass _PAGE_RW to hash_page(), it will set _PAGE_DIRTY (since we track dirty that way, by hash faulting !dirty) which is not what we want. In fact, the correct fix is to always pass 0. That means that only read-only or already dirty read write PTEs will be preloaded. The (hopefully rare) case of a non dirty read write PTE can't be preloaded this way, it will have to fault in hash_page on the actual access. Signed-off-by: Benjamin Herrenschmidt Signed-off-by: Linus Torvalds --- diff --git a/arch/ppc64/mm/init.c b/arch/ppc64/mm/init.c index c2157c9c3a..be64b157af 100644 --- a/arch/ppc64/mm/init.c +++ b/arch/ppc64/mm/init.c @@ -799,8 +799,7 @@ void update_mmu_cache(struct vm_area_struct *vma, unsigned long ea, if (cpus_equal(vma->vm_mm->cpu_vm_mask, tmp)) local = 1; - __hash_page(ea, pte_val(pte) & (_PAGE_USER|_PAGE_RW), vsid, ptep, - 0x300, local); + __hash_page(ea, 0, vsid, ptep, 0x300, local); local_irq_restore(flags); }