diff options
| -rw-r--r-- | drivers/gpu/drm/i915/i915_gem.c | 6 | ||||
| -rw-r--r-- | drivers/gpu/drm/i915/i915_gem_execbuffer.c | 2 | ||||
| -rw-r--r-- | include/linux/pagemap.h | 64 |
3 files changed, 66 insertions, 6 deletions
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c index e9cac478cced..6dc832902f53 100644 --- a/drivers/gpu/drm/i915/i915_gem.c +++ b/drivers/gpu/drm/i915/i915_gem.c @@ -416,7 +416,7 @@ i915_gem_shmem_pread(struct drm_device *dev, mutex_unlock(&dev->struct_mutex); if (!prefaulted) { - ret = fault_in_pages_writeable(user_data, remain); + ret = fault_in_multipages_writeable(user_data, remain); /* Userspace is tricking us, but we've already clobbered * its pages with the prefault and promised to write the * data up to the first fault. Hence ignore any errors @@ -809,8 +809,8 @@ i915_gem_pwrite_ioctl(struct drm_device *dev, void *data, args->size)) return -EFAULT; - ret = fault_in_pages_readable((char __user *)(uintptr_t)args->data_ptr, - args->size); + ret = fault_in_multipages_readable((char __user *)(uintptr_t)args->data_ptr, + args->size); if (ret) return -EFAULT; diff --git a/drivers/gpu/drm/i915/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/i915_gem_execbuffer.c index eb85860001ec..8e0b686d3afb 100644 --- a/drivers/gpu/drm/i915/i915_gem_execbuffer.c +++ b/drivers/gpu/drm/i915/i915_gem_execbuffer.c @@ -997,7 +997,7 @@ validate_exec_list(struct drm_i915_gem_exec_object2 *exec, if (!access_ok(VERIFY_WRITE, ptr, length)) return -EFAULT; - if (fault_in_pages_readable(ptr, length)) + if (fault_in_multipages_readable(ptr, length)) return -EFAULT; } diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h index cfaaa6949b8b..c93a9a9bcd35 100644 --- a/include/linux/pagemap.h +++ b/include/linux/pagemap.h @@ -426,7 +426,7 @@ static inline int fault_in_pages_writeable(char __user *uaddr, int size) */ if (((unsigned long)uaddr & PAGE_MASK) != ((unsigned long)end & PAGE_MASK)) - ret = __put_user(0, end); + ret = __put_user(0, end); } return ret; } @@ -445,13 +445,73 @@ static inline int fault_in_pages_readable(const char __user *uaddr, int size) if (((unsigned long)uaddr & PAGE_MASK) != ((unsigned long)end & PAGE_MASK)) { - ret = __get_user(c, end); + ret = __get_user(c, end); (void)c; } } return ret; } +/* + * Multipage variants of the above prefault helpers, useful if more than + * PAGE_SIZE of data needs to be prefaulted. These are separate from the above + * functions (which only handle up to PAGE_SIZE) to avoid clobbering the + * filemap.c hotpaths. + */ +static inline int fault_in_multipages_writeable(char __user *uaddr, int size) +{ + int ret; + const char __user *end = uaddr + size - 1; + + if (unlikely(size == 0)) + return 0; + + /* + * Writing zeroes into userspace here is OK, because we know that if + * the zero gets there, we'll be overwriting it. + */ + while (uaddr <= end) { + ret = __put_user(0, uaddr); + if (ret != 0) + return ret; + uaddr += PAGE_SIZE; + } + + /* Check whether the range spilled into the next page. */ + if (((unsigned long)uaddr & PAGE_MASK) == + ((unsigned long)end & PAGE_MASK)) + ret = __put_user(0, end); + + return ret; +} + +static inline int fault_in_multipages_readable(const char __user *uaddr, + int size) +{ + volatile char c; + int ret; + const char __user *end = uaddr + size - 1; + + if (unlikely(size == 0)) + return 0; + + while (uaddr <= end) { + ret = __get_user(c, uaddr); + if (ret != 0) + return ret; + uaddr += PAGE_SIZE; + } + + /* Check whether the range spilled into the next page. */ + if (((unsigned long)uaddr & PAGE_MASK) == + ((unsigned long)end & PAGE_MASK)) { + ret = __get_user(c, end); + (void)c; + } + + return ret; +} + int add_to_page_cache_locked(struct page *page, struct address_space *mapping, pgoff_t index, gfp_t gfp_mask); int add_to_page_cache_lru(struct page *page, struct address_space *mapping, |