[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-changelog] Fix x86/64 pagetable initialisation so that only things that
# HG changeset patch # User kaf24@xxxxxxxxxxxxxxxxxxxx # Node ID c42a9e2f6c5b270cbcbfc9b918de9b66750448b3 # Parent bca2fd76995ea8c811cc52a7edaabaeae03a677a Fix x86/64 pagetable initialisation so that only things that need to be are mapped read-only. Signed-off-by: Keir Fraser <keir@xxxxxxxxxxxxx> diff -r bca2fd76995e -r c42a9e2f6c5b linux-2.6-xen-sparse/arch/xen/x86_64/mm/init.c --- a/linux-2.6-xen-sparse/arch/xen/x86_64/mm/init.c Wed Aug 24 15:21:48 2005 +++ b/linux-2.6-xen-sparse/arch/xen/x86_64/mm/init.c Wed Aug 24 15:22:44 2005 @@ -441,6 +441,31 @@ *dst = val; } +static inline int make_readonly(unsigned long paddr) +{ + int readonly = 0; + + /* Make new page tables read-only. */ + if ((paddr < ((table_start << PAGE_SHIFT) + tables_space)) && + (paddr >= (table_start << PAGE_SHIFT))) + readonly = 1; + + /* Make old page tables read-only. */ + if ((paddr < ((xen_start_info.pt_base - __START_KERNEL_map) + + (xen_start_info.nr_pt_frames << PAGE_SHIFT))) && + (paddr >= (xen_start_info.pt_base - __START_KERNEL_map))) + readonly = 1; + + /* + * No need for writable mapping of kernel image. This also ensures that + * page and descriptor tables embedded inside don't have writable mappings. + */ + if ((paddr >= __pa_symbol(&_text)) && (paddr < __pa_symbol(&_end))) + readonly = 1; + + return readonly; +} + void __init phys_pud_init(pud_t *pud, unsigned long address, unsigned long end) { long i, j, k; @@ -477,9 +502,7 @@ pte = alloc_low_page(&pte_phys); pte_save = pte; for (k = 0; k < PTRS_PER_PTE; pte++, k++, paddr += PTE_SIZE) { - if (paddr < (table_start << PAGE_SHIFT) - + tables_space) - { + if (make_readonly(paddr)) { __set_pte(pte, __pte(paddr | (_KERNPG_TABLE & ~_PAGE_RW))); continue; diff -r bca2fd76995e -r c42a9e2f6c5b xen/arch/x86/mm.c --- a/xen/arch/x86/mm.c Wed Aug 24 15:21:48 2005 +++ b/xen/arch/x86/mm.c Wed Aug 24 15:22:44 2005 @@ -1449,8 +1449,10 @@ if ( ((x & PGT_type_mask) != PGT_l2_page_table) || ((type & PGT_type_mask) != PGT_l1_page_table) ) MEM_LOG("Bad type (saw %" PRtype_info - "!= exp %" PRtype_info ") for pfn %lx", - x, type, page_to_pfn(page)); + "!= exp %" PRtype_info ") " + "for mfn %lx (pfn %x)", + x, type, page_to_pfn(page), + machine_to_phys_mapping[page_to_pfn(page)]); return 0; } else if ( (x & PGT_va_mask) == PGT_va_mutable ) _______________________________________________ Xen-changelog mailing list Xen-changelog@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-changelog
|
![]() |
Lists.xenproject.org is hosted with RackSpace, monitoring our |