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| author | Stefano Stabellini <stefano.stabellini@eu.citrix.com> | 2011-04-19 14:47:31 +0100 |
|---|---|---|
| committer | Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> | 2011-04-20 09:43:13 -0400 |
| commit | ee176455e28469e2420032aab3db11ac2ae3eaa8 (patch) | |
| tree | e8cfbf2cfd2a0617bb3a24d8851b2cde1eee2709 /arch | |
| parent | 24bdb0b62cc82120924762ae6bc85afc8c3f2b26 (diff) | |
| download | talos-op-linux-ee176455e28469e2420032aab3db11ac2ae3eaa8.tar.gz talos-op-linux-ee176455e28469e2420032aab3db11ac2ae3eaa8.zip | |
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.c | 13 |
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 */ |
