Messages in this thread | | | Date | Thu, 5 Nov 2015 18:15:14 +0800 | From | Xishi Qiu <> | Subject | Re: [PATCH 1/2] arm64: Get existing page protections in split_pmd |
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On 2015/11/4 5:48, Laura Abbott wrote:
> > Rather than always putting the least restrictived permissions > (PAGE_KERNEL_EXEC) when spliting a pmd into pages, use > the existing permissions from the pmd for the page. > > Signed-off-by: Laura Abbott <labbott@fedoraproject.org> > --- > arch/arm64/mm/mmu.c | 9 ++++----- > 1 file changed, 4 insertions(+), 5 deletions(-) > > diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c > index 9211b85..ff41efa 100644 > --- a/arch/arm64/mm/mmu.c > +++ b/arch/arm64/mm/mmu.c > @@ -75,14 +75,13 @@ static void __init *early_alloc(unsigned long sz) > static void split_pmd(pmd_t *pmd, pte_t *pte) > { > unsigned long pfn = pmd_pfn(*pmd); > + unsigned long addr = pfn << PAGE_SHIFT; > + pgprot_t prot = __pgprot(pmd_val(*pmd) ^ addr) | PTE_TYPE_PAGE; > +
Hi Laura,
I'm not quite understand, I find split_pud() doesn't set the flag PMD_TYPE_TABLE. If we clear xx_TABLE_BIT, does that means the page is large page? And what is the different from the flag xx_TYPE_SECT?
Thanks, Xishi Qiu
> int i = 0; > > do { > - /* > - * Need to have the least restrictive permissions available > - * permissions will be fixed up later > - */ > - set_pte(pte, pfn_pte(pfn, PAGE_KERNEL_EXEC)); > + set_pte(pte, pfn_pte(pfn, prot));
> pfn++; > } while (pte++, i++, i < PTRS_PER_PTE); > }
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