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    Annotation of /trunk/kernel26-xen/patches-2.6.25-r1/1069-2.6.25-xen-Try-to-make-pagetables-read-only.patch

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    Revision 606 - (hide annotations) (download)
    Thu May 22 23:13:13 2008 UTC (16 years ago) by niro
    File size: 3534 byte(s) 
    -ver bump to 2.6.25-magellan-r1:
- linux-2.6.25.4
- fbcondecor-0.9.4
- squashfs-3.3
- unionfs-2.3.3
- tuxonice-3.0-rc7
- linux-phc-0.3.0
- acpi-dstd-0.9a
- reiser4
- xen-3.2.0
. ipw3945-1.2.2
    1 niro 606 From 856b9dd6237a7f7dacd949c8f0f50ec21fbf7368 Mon Sep 17 00:00:00 2001
    2     From: Eduardo Habkost <ehabkost@redhat.com>
    3     Date: Tue, 18 Dec 2007 10:21:45 -0200
    4     Subject: [PATCH] Try to make pagetables read-only
    5    
    6     Not working yet. :(
    7    
    8     Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
    9     ---
    10     arch/x86/mm/init_64.c | 81 +++++++++++++++++++++++++++++++++++++++++++++++++
    11     1 files changed, 81 insertions(+), 0 deletions(-)
    12    
    13     diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c
    14     index a6f2051..cf1453b 100644
    15     --- a/arch/x86/mm/init_64.c
    16     +++ b/arch/x86/mm/init_64.c
    17     @@ -70,6 +70,85 @@ static unsigned long dma_reserve __initdata;
    18    
    19     DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);
    20    
    21     +#ifdef CONFIG_XEN
    22     +
    23     +static void __make_page_readonly(void *va)
    24     +{
    25     + pgd_t *pgd; pud_t *pud; pmd_t *pmd; pte_t pte, *ptep;
    26     + unsigned long addr = (unsigned long) va;
    27     +
    28     + xprintk("%s(%p)\n", __func__, va);
    29     +
    30     + pgd = pgd_offset_k(addr);
    31     + pud = pud_offset(pgd, addr);
    32     + pmd = pmd_offset(pud, addr);
    33     + ptep = pte_offset_kernel(pmd, addr);
    34     +
    35     + pte.pte = ptep->pte & ~_PAGE_RW;
    36     + xprintk("update_va_mapping: %lx, %lx\n", addr, pte);
    37     +
    38     + if (HYPERVISOR_update_va_mapping(addr, pte, 0))
    39     + BUG(); //xen_l1_entry_update(ptep, pte); /* fallback */
    40     +
    41     + if ((addr >= VMALLOC_START) && (addr < VMALLOC_END))
    42     + __make_page_readonly(__va(pte_pfn(pte) << PAGE_SHIFT));
    43     +}
    44     +
    45     +static void __make_page_writable(void *va)
    46     +{
    47     + pgd_t *pgd; pud_t *pud; pmd_t *pmd; pte_t pte, *ptep;
    48     + unsigned long addr = (unsigned long) va;
    49     +
    50     + pgd = pgd_offset_k(addr);
    51     + pud = pud_offset(pgd, addr);
    52     + pmd = pmd_offset(pud, addr);
    53     + ptep = pte_offset_kernel(pmd, addr);
    54     +
    55     + pte.pte = ptep->pte | _PAGE_RW;
    56     + if (HYPERVISOR_update_va_mapping(addr, pte, 0))
    57     + BUG();//xen_l1_entry_update(ptep, pte); /* fallback */
    58     +
    59     + if ((addr >= VMALLOC_START) && (addr < VMALLOC_END))
    60     + __make_page_writable(__va(pte_pfn(pte) << PAGE_SHIFT));
    61     +}
    62     +
    63     +void make_page_readonly(void *va, unsigned int feature)
    64     +{
    65     + if (!xen_feature(feature))
    66     + __make_page_readonly(va);
    67     +}
    68     +
    69     +void make_page_writable(void *va, unsigned int feature)
    70     +{
    71     + if (!xen_feature(feature))
    72     + __make_page_writable(va);
    73     +}
    74     +
    75     +void make_pages_readonly(void *va, unsigned nr, unsigned int feature)
    76     +{
    77     + if (xen_feature(feature))
    78     + return;
    79     +
    80     + while (nr-- != 0) {
    81     + __make_page_readonly(va);
    82     + va = (void*)((unsigned long)va + PAGE_SIZE);
    83     + }
    84     +}
    85     +
    86     +void make_pages_writable(void *va, unsigned nr, unsigned int feature)
    87     +{
    88     + if (xen_feature(feature))
    89     + return;
    90     +
    91     + while (nr-- != 0) {
    92     + __make_page_writable(va);
    93     + va = (void*)((unsigned long)va + PAGE_SIZE);
    94     + }
    95     +}
    96     +
    97     +
    98     +#endif
    99     +
    100     /*
    101     * NOTE: pagetable_init alloc all the fixmap pagetables contiguous on the
    102     * physical space so we can cache the place of the first one and move
    103     @@ -150,6 +229,7 @@ set_pte_vaddr_pud(pud_t *pud_page, unsigned long vaddr, pte_t pteval)
    104     pud = pud_page + pud_index(vaddr);
    105     if (pud_none(*pud)) {
    106     pmd = (pmd_t *) spp_getpage();
    107     + make_page_readonly(pmd, XENFEAT_writable_page_tables);
    108     set_pud(pud, __pud(__pa(pmd) | _KERNPG_TABLE | _PAGE_USER));
    109     if (pmd != pmd_offset(pud, 0)) {
    110     printk(KERN_ERR "PAGETABLE BUG #01! %p <-> %p\n",
    111     @@ -160,6 +240,7 @@ set_pte_vaddr_pud(pud_t *pud_page, unsigned long vaddr, pte_t pteval)
    112     pmd = pmd_offset(pud, vaddr);
    113     if (pmd_none(*pmd)) {
    114     pte = (pte_t *) spp_getpage();
    115     + make_page_readonly(pte, XENFEAT_writable_page_tables);
    116     set_pmd(pmd, __pmd(__pa(pte) | _KERNPG_TABLE | _PAGE_USER));
    117     if (pte != pte_offset_kernel(pmd, 0)) {
    118     printk(KERN_ERR "PAGETABLE BUG #02!\n");
    119     --
    120     1.5.4.1
    121