ae531c26c5
This patch introduces a restriction on /dev/mem: Only non-memory can be read or written unless the newly introduced config option is set. The X server needs access to /dev/mem for the PCI space, but it doesn't need access to memory; both the file permissions and SELinux permissions of /dev/mem just make X effectively super-super powerful. With the exception of the BIOS area, there's just no valid app that uses /dev/mem on actual memory. Other popular users of /dev/mem are rootkits and the like. (note: mmap access of memory via /dev/mem was already not allowed since a really long time) People who want to use /dev/mem for kernel debugging can enable the config option. The restrictions of this patch have been in the Fedora and RHEL kernels for at least 4 years without any problems. Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
185 lines
4.3 KiB
C
185 lines
4.3 KiB
C
#ifndef _ASM_X86_PAGE_H
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#define _ASM_X86_PAGE_H
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#include <linux/const.h>
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/* PAGE_SHIFT determines the page size */
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#define PAGE_SHIFT 12
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#define PAGE_SIZE (_AC(1,UL) << PAGE_SHIFT)
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#define PAGE_MASK (~(PAGE_SIZE-1))
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#ifdef __KERNEL__
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#define PHYSICAL_PAGE_MASK (PAGE_MASK & __PHYSICAL_MASK)
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#define PTE_MASK (_AT(long, PHYSICAL_PAGE_MASK))
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#define PMD_PAGE_SIZE (_AC(1, UL) << PMD_SHIFT)
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#define PMD_PAGE_MASK (~(PMD_PAGE_SIZE-1))
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#define HPAGE_SHIFT PMD_SHIFT
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#define HPAGE_SIZE (_AC(1,UL) << HPAGE_SHIFT)
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#define HPAGE_MASK (~(HPAGE_SIZE - 1))
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#define HUGETLB_PAGE_ORDER (HPAGE_SHIFT - PAGE_SHIFT)
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/* to align the pointer to the (next) page boundary */
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#define PAGE_ALIGN(addr) (((addr)+PAGE_SIZE-1)&PAGE_MASK)
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#define __PHYSICAL_MASK _AT(phys_addr_t, (_AC(1,ULL) << __PHYSICAL_MASK_SHIFT) - 1)
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#define __VIRTUAL_MASK ((_AC(1,UL) << __VIRTUAL_MASK_SHIFT) - 1)
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#ifndef __ASSEMBLY__
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#include <linux/types.h>
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#endif
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#ifdef CONFIG_X86_64
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#include <asm/page_64.h>
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#else
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#include <asm/page_32.h>
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#endif /* CONFIG_X86_64 */
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#define PAGE_OFFSET ((unsigned long)__PAGE_OFFSET)
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#define VM_DATA_DEFAULT_FLAGS \
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(((current->personality & READ_IMPLIES_EXEC) ? VM_EXEC : 0 ) | \
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VM_READ | VM_WRITE | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC)
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#ifndef __ASSEMBLY__
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extern int page_is_ram(unsigned long pagenr);
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extern int devmem_is_allowed(unsigned long pagenr);
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extern unsigned long max_pfn_mapped;
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struct page;
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static inline void clear_user_page(void *page, unsigned long vaddr,
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struct page *pg)
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{
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clear_page(page);
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}
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static inline void copy_user_page(void *to, void *from, unsigned long vaddr,
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struct page *topage)
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{
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copy_page(to, from);
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}
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#define __alloc_zeroed_user_highpage(movableflags, vma, vaddr) \
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alloc_page_vma(GFP_HIGHUSER | __GFP_ZERO | movableflags, vma, vaddr)
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#define __HAVE_ARCH_ALLOC_ZEROED_USER_HIGHPAGE
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typedef struct { pgdval_t pgd; } pgd_t;
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typedef struct { pgprotval_t pgprot; } pgprot_t;
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static inline pgd_t native_make_pgd(pgdval_t val)
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{
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return (pgd_t) { val };
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}
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static inline pgdval_t native_pgd_val(pgd_t pgd)
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{
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return pgd.pgd;
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}
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#if PAGETABLE_LEVELS >= 3
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#if PAGETABLE_LEVELS == 4
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typedef struct { pudval_t pud; } pud_t;
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static inline pud_t native_make_pud(pmdval_t val)
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{
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return (pud_t) { val };
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}
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static inline pudval_t native_pud_val(pud_t pud)
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{
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return pud.pud;
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}
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#else /* PAGETABLE_LEVELS == 3 */
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#include <asm-generic/pgtable-nopud.h>
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static inline pudval_t native_pud_val(pud_t pud)
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{
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return native_pgd_val(pud.pgd);
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}
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#endif /* PAGETABLE_LEVELS == 4 */
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typedef struct { pmdval_t pmd; } pmd_t;
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static inline pmd_t native_make_pmd(pmdval_t val)
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{
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return (pmd_t) { val };
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}
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static inline pmdval_t native_pmd_val(pmd_t pmd)
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{
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return pmd.pmd;
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}
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#else /* PAGETABLE_LEVELS == 2 */
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#include <asm-generic/pgtable-nopmd.h>
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static inline pmdval_t native_pmd_val(pmd_t pmd)
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{
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return native_pgd_val(pmd.pud.pgd);
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}
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#endif /* PAGETABLE_LEVELS >= 3 */
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static inline pte_t native_make_pte(pteval_t val)
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{
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return (pte_t) { .pte = val };
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}
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static inline pteval_t native_pte_val(pte_t pte)
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{
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return pte.pte;
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}
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#define pgprot_val(x) ((x).pgprot)
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#define __pgprot(x) ((pgprot_t) { (x) } )
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#ifdef CONFIG_PARAVIRT
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#include <asm/paravirt.h>
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#else /* !CONFIG_PARAVIRT */
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#define pgd_val(x) native_pgd_val(x)
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#define __pgd(x) native_make_pgd(x)
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#ifndef __PAGETABLE_PUD_FOLDED
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#define pud_val(x) native_pud_val(x)
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#define __pud(x) native_make_pud(x)
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#endif
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#ifndef __PAGETABLE_PMD_FOLDED
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#define pmd_val(x) native_pmd_val(x)
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#define __pmd(x) native_make_pmd(x)
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#endif
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#define pte_val(x) native_pte_val(x)
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#define __pte(x) native_make_pte(x)
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#endif /* CONFIG_PARAVIRT */
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#define __pa(x) __phys_addr((unsigned long)(x))
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/* __pa_symbol should be used for C visible symbols.
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This seems to be the official gcc blessed way to do such arithmetic. */
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#define __pa_symbol(x) __pa(__phys_reloc_hide((unsigned long)(x)))
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#define __va(x) ((void *)((unsigned long)(x)+PAGE_OFFSET))
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#define __boot_va(x) __va(x)
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#define __boot_pa(x) __pa(x)
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#define virt_to_page(kaddr) pfn_to_page(__pa(kaddr) >> PAGE_SHIFT)
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#define pfn_to_kaddr(pfn) __va((pfn) << PAGE_SHIFT)
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#define virt_addr_valid(kaddr) pfn_valid(__pa(kaddr) >> PAGE_SHIFT)
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#endif /* __ASSEMBLY__ */
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#include <asm-generic/memory_model.h>
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#include <asm-generic/page.h>
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#define __HAVE_ARCH_GATE_AREA 1
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#endif /* __KERNEL__ */
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#endif /* _ASM_X86_PAGE_H */
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