diff options
Diffstat (limited to 'mm/nommu.c')
| -rw-r--r-- | mm/nommu.c | 31 |
1 files changed, 26 insertions, 5 deletions
diff --git a/mm/nommu.c b/mm/nommu.c index bf0cc762a7d2..66e81e7e9fe9 100644 --- a/mm/nommu.c +++ b/mm/nommu.c @@ -69,9 +69,6 @@ int sysctl_max_map_count = DEFAULT_MAX_MAP_COUNT; int sysctl_nr_trim_pages = CONFIG_NOMMU_INITIAL_TRIM_EXCESS; int heap_stack_gap = 0; -/* amount of vm to protect from userspace access */ -unsigned long mmap_min_addr = CONFIG_DEFAULT_MMAP_MIN_ADDR; - atomic_long_t mmap_pages_allocated; EXPORT_SYMBOL(mem_map); @@ -238,6 +235,27 @@ int get_user_pages(struct task_struct *tsk, struct mm_struct *mm, } EXPORT_SYMBOL(get_user_pages); +/** + * follow_pfn - look up PFN at a user virtual address + * @vma: memory mapping + * @address: user virtual address + * @pfn: location to store found PFN + * + * Only IO mappings and raw PFN mappings are allowed. + * + * Returns zero and the pfn at @pfn on success, -ve otherwise. + */ +int follow_pfn(struct vm_area_struct *vma, unsigned long address, + unsigned long *pfn) +{ + if (!(vma->vm_flags & (VM_IO | VM_PFNMAP))) + return -EINVAL; + + *pfn = address >> PAGE_SHIFT; + return 0; +} +EXPORT_SYMBOL(follow_pfn); + DEFINE_RWLOCK(vmlist_lock); struct vm_struct *vmlist; @@ -901,6 +919,10 @@ static int validate_mmap_request(struct file *file, if (!file->f_op->read) capabilities &= ~BDI_CAP_MAP_COPY; + /* The file shall have been opened with read permission. */ + if (!(file->f_mode & FMODE_READ)) + return -EACCES; + if (flags & MAP_SHARED) { /* do checks for writing, appending and locking */ if ((prot & PROT_WRITE) && @@ -1330,6 +1352,7 @@ unsigned long do_mmap_pgoff(struct file *file, } vma->vm_region = region; + add_nommu_region(region); /* set up the mapping */ if (file && vma->vm_flags & VM_SHARED) @@ -1339,8 +1362,6 @@ unsigned long do_mmap_pgoff(struct file *file, if (ret < 0) goto error_put_region; - add_nommu_region(region); - /* okay... we have a mapping; now we have to register it */ result = vma->vm_start; |