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[PATCH] x86: Improve handling of kernel mappings in change_page_attr

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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 <jbeulich@novell.com>
Signed-off-by: Andi Kleen <ak@suse.de>
This commit is contained in:
Jan Beulich 2007-05-02 19:27:10 +02:00 committed by Andi Kleen
parent 90a0a06aa8
commit d01ad8dd56
3 changed files with 16 additions and 6 deletions
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4
arch/i386/mm/pageattr.c
View File

@ -142,7 +142,7 @@ __change_page_attr(struct page *page, pgprot_t prot)
return -EINVAL;
kpte_page = virt_to_page(kpte);
if (pgprot_val(prot) != pgprot_val(PAGE_KERNEL)) {
if ((pte_val(*kpte) & _PAGE_PSE) == 0) {
if (!pte_huge(*kpte)) {
set_pte_atomic(kpte, mk_pte(page, prot));
} else {
pgprot_t ref_prot;
@ -158,7 +158,7 @@ __change_page_attr(struct page *page, pgprot_t prot)
kpte_page = split;
}
page_private(kpte_page)++;
} else if ((pte_val(*kpte) & _PAGE_PSE) == 0) {
} else if (!pte_huge(*kpte)) {
set_pte_atomic(kpte, mk_pte(page, PAGE_KERNEL));
BUG_ON(page_private(kpte_page) == 0);
page_private(kpte_page)--;

16
arch/x86_64/mm/pageattr.c
View File

@ -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) &&

2
include/asm-i386/pgtable.h
View File

@ -159,6 +159,7 @@ void paging_init(void);
extern unsigned long long __PAGE_KERNEL, __PAGE_KERNEL_EXEC;
#define __PAGE_KERNEL_RO (__PAGE_KERNEL & ~_PAGE_RW)
#define __PAGE_KERNEL_RX (__PAGE_KERNEL_EXEC & ~_PAGE_RW)
#define __PAGE_KERNEL_NOCACHE (__PAGE_KERNEL | _PAGE_PCD)
#define __PAGE_KERNEL_LARGE (__PAGE_KERNEL | _PAGE_PSE)
#define __PAGE_KERNEL_LARGE_EXEC (__PAGE_KERNEL_EXEC | _PAGE_PSE)
@ -166,6 +167,7 @@ extern unsigned long long __PAGE_KERNEL, __PAGE_KERNEL_EXEC;
#define PAGE_KERNEL __pgprot(__PAGE_KERNEL)
#define PAGE_KERNEL_RO __pgprot(__PAGE_KERNEL_RO)
#define PAGE_KERNEL_EXEC __pgprot(__PAGE_KERNEL_EXEC)
#define PAGE_KERNEL_RX __pgprot(__PAGE_KERNEL_RX)
#define PAGE_KERNEL_NOCACHE __pgprot(__PAGE_KERNEL_NOCACHE)
#define PAGE_KERNEL_LARGE __pgprot(__PAGE_KERNEL_LARGE)
#define PAGE_KERNEL_LARGE_EXEC __pgprot(__PAGE_KERNEL_LARGE_EXEC)