diff options
Diffstat (limited to 'drivers/char/mem.c')
| -rw-r--r-- | drivers/char/mem.c | 41 |
1 files changed, 11 insertions, 30 deletions
diff --git a/drivers/char/mem.c b/drivers/char/mem.c index 83495885ada0..56b2fb4fbc93 100644 --- a/drivers/char/mem.c +++ b/drivers/char/mem.c @@ -41,36 +41,7 @@ */ static inline int uncached_access(struct file *file, unsigned long addr) { -#if defined(__i386__) && !defined(__arch_um__) - /* - * On the PPro and successors, the MTRRs are used to set - * memory types for physical addresses outside main memory, - * so blindly setting PCD or PWT on those pages is wrong. - * For Pentiums and earlier, the surround logic should disable - * caching for the high addresses through the KEN pin, but - * we maintain the tradition of paranoia in this code. - */ - if (file->f_flags & O_SYNC) - return 1; - return !( test_bit(X86_FEATURE_MTRR, boot_cpu_data.x86_capability) || - test_bit(X86_FEATURE_K6_MTRR, boot_cpu_data.x86_capability) || - test_bit(X86_FEATURE_CYRIX_ARR, boot_cpu_data.x86_capability) || - test_bit(X86_FEATURE_CENTAUR_MCR, boot_cpu_data.x86_capability) ) - && addr >= __pa(high_memory); -#elif defined(__x86_64__) && !defined(__arch_um__) - /* - * This is broken because it can generate memory type aliases, - * which can cause cache corruptions - * But it is only available for root and we have to be bug-to-bug - * compatible with i386. - */ - if (file->f_flags & O_SYNC) - return 1; - /* same behaviour as i386. PAT always set to cached and MTRRs control the - caching behaviour. - Hopefully a full PAT implementation will fix that soon. */ - return 0; -#elif defined(CONFIG_IA64) +#if defined(CONFIG_IA64) /* * On ia64, we ignore O_SYNC because we cannot tolerate memory attribute aliases. */ @@ -283,6 +254,12 @@ static ssize_t write_mem(struct file * file, const char __user * buf, return written; } +int __attribute__((weak)) phys_mem_access_prot_allowed(struct file *file, + unsigned long pfn, unsigned long size, pgprot_t *vma_prot) +{ + return 1; +} + #ifndef __HAVE_PHYS_MEM_ACCESS_PROT static pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn, unsigned long size, pgprot_t vma_prot) @@ -336,6 +313,10 @@ static int mmap_mem(struct file * file, struct vm_area_struct * vma) if (!range_is_allowed(vma->vm_pgoff, size)) return -EPERM; + if (!phys_mem_access_prot_allowed(file, vma->vm_pgoff, size, + &vma->vm_page_prot)) + return -EINVAL; + vma->vm_page_prot = phys_mem_access_prot(file, vma->vm_pgoff, size, vma->vm_page_prot); |