From d01ad8dd56527be72947b4b9997bb2c05783c3ed Mon Sep 17 00:00:00 2001 From: Jan Beulich Date: Wed, 2 May 2007 19:27:10 +0200 Subject: [PATCH] x86: Improve handling of kernel mappings in change_page_attr Fix various broken corner cases in i386 and x86-64 change_page_attr. AK: split off from tighten kernel image access rights Signed-off-by: Jan Beulich Signed-off-by: Andi Kleen --- arch/x86_64/mm/pageattr.c | 16 ++++++++++++---- 1 file changed, 12 insertions(+), 4 deletions(-) (limited to 'arch/x86_64') diff --git a/arch/x86_64/mm/pageattr.c b/arch/x86_64/mm/pageattr.c index 76ee90a5abe..bf4aa8dd425 100644 --- a/arch/x86_64/mm/pageattr.c +++ b/arch/x86_64/mm/pageattr.c @@ -179,16 +179,24 @@ __change_page_attr(unsigned long address, unsigned long pfn, pgprot_t prot, int change_page_attr_addr(unsigned long address, int numpages, pgprot_t prot) { unsigned long phys_base_pfn = __pa_symbol(__START_KERNEL_map) >> PAGE_SHIFT; - int err = 0; + int err = 0, kernel_map = 0; int i; + if (address >= __START_KERNEL_map + && address < __START_KERNEL_map + KERNEL_TEXT_SIZE) { + address = (unsigned long)__va(__pa(address)); + kernel_map = 1; + } + down_write(&init_mm.mmap_sem); for (i = 0; i < numpages; i++, address += PAGE_SIZE) { unsigned long pfn = __pa(address) >> PAGE_SHIFT; - err = __change_page_attr(address, pfn, prot, PAGE_KERNEL); - if (err) - break; + if (!kernel_map || pte_present(pfn_pte(0, prot))) { + err = __change_page_attr(address, pfn, prot, PAGE_KERNEL); + if (err) + break; + } /* Handle kernel mapping too which aliases part of the * lowmem */ if ((pfn >= phys_base_pfn) && -- cgit v1.2.3