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authorStefano Stabellini <stefano.stabellini@eu.citrix.com>2011-04-19 14:47:31 +0100
committerKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>2011-04-20 09:43:13 -0400
commitee176455e28469e2420032aab3db11ac2ae3eaa8 (patch)
treee8cfbf2cfd2a0617bb3a24d8851b2cde1eee2709 /arch
parent24bdb0b62cc82120924762ae6bc85afc8c3f2b26 (diff)
downloadlinux-ee176455e28469e2420032aab3db11ac2ae3eaa8.tar.bz2
xen: mask_rw_pte: do not apply the early_ioremap checks on x86_32
The two "is_early_ioremap_ptep" checks in mask_rw_pte are only used on x86_64, in fact early_ioremap is not used at all to setup the initial pagetable on x86_32. Moreover on x86_32 the two checks are wrong because the range pgt_buf_start..pgt_buf_end initially should be mapped RW because the pages in the range are not pagetable pages yet and haven't been cleared yet. Afterwards considering the pgt_buf_start..pgt_buf_end is part of the initial mapping, xen_alloc_pte is capable of turning the ptes RO when they become pagetable pages. Fix the issue and improve the readability of the code providing two different implementation of mask_rw_pte for x86_32 and x86_64. Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/xen/mmu.c13
1 files changed, 9 insertions, 4 deletions
diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c
index a991b57f91fe..aef7af92b28b 100644
--- a/arch/x86/xen/mmu.c
+++ b/arch/x86/xen/mmu.c
@@ -1473,16 +1473,20 @@ static void xen_pgd_free(struct mm_struct *mm, pgd_t *pgd)
#endif
}
+#ifdef CONFIG_X86_32
static __init pte_t mask_rw_pte(pte_t *ptep, pte_t pte)
{
- unsigned long pfn = pte_pfn(pte);
-
-#ifdef CONFIG_X86_32
/* If there's an existing pte, then don't allow _PAGE_RW to be set */
if (pte_val_ma(*ptep) & _PAGE_PRESENT)
pte = __pte_ma(((pte_val_ma(*ptep) & _PAGE_RW) | ~_PAGE_RW) &
pte_val_ma(pte));
-#endif
+
+ return pte;
+}
+#else /* CONFIG_X86_64 */
+static __init pte_t mask_rw_pte(pte_t *ptep, pte_t pte)
+{
+ unsigned long pfn = pte_pfn(pte);
/*
* If the new pfn is within the range of the newly allocated
@@ -1497,6 +1501,7 @@ static __init pte_t mask_rw_pte(pte_t *ptep, pte_t pte)
return pte;
}
+#endif /* CONFIG_X86_64 */
/* Init-time set_pte while constructing initial pagetables, which
doesn't allow RO pagetable pages to be remapped RW */