drm/i915: rewrite shmem_pread_slow to use copy_to_user
Like for shmem_pwrite_slow. The only difference is that because we read data, we can leave the fetched cachelines in the cpu: In the case that the object isn't in the cpu read domain anymore, the clflush for the next cpu read domain invalidation will simply drop these cachelines. slow_shmem_bit17_copy is now ununsed, so kill it. With this patch tests/gem_mmap_gtt now actually works. v2: add __ to copy_to_user_swizzled as suggested by Chris Wilson. v3: Fixup the swizzling logic, it swizzled the wrong pages. Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=38115 Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
This commit is contained in:
Daniel Vetter
Родитель
8c59967c44
Коммит
8461d22677
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@ -259,73 +259,6 @@ static int i915_gem_object_needs_bit17_swizzle(struct drm_i915_gem_object *obj)
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obj->tiling_mode != I915_TILING_NONE;
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}
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static inline void
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slow_shmem_copy(struct page *dst_page,
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int dst_offset,
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struct page *src_page,
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int src_offset,
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int length)
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{
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char *dst_vaddr, *src_vaddr;
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dst_vaddr = kmap(dst_page);
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src_vaddr = kmap(src_page);
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memcpy(dst_vaddr + dst_offset, src_vaddr + src_offset, length);
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kunmap(src_page);
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kunmap(dst_page);
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}
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static inline void
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slow_shmem_bit17_copy(struct page *gpu_page,
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int gpu_offset,
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struct page *cpu_page,
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int cpu_offset,
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int length,
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int is_read)
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{
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char *gpu_vaddr, *cpu_vaddr;
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/* Use the unswizzled path if this page isn't affected. */
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if ((page_to_phys(gpu_page) & (1 << 17)) == 0) {
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if (is_read)
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return slow_shmem_copy(cpu_page, cpu_offset,
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gpu_page, gpu_offset, length);
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else
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return slow_shmem_copy(gpu_page, gpu_offset,
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cpu_page, cpu_offset, length);
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}
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gpu_vaddr = kmap(gpu_page);
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cpu_vaddr = kmap(cpu_page);
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/* Copy the data, XORing A6 with A17 (1). The user already knows he's
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* XORing with the other bits (A9 for Y, A9 and A10 for X)
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*/
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while (length > 0) {
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int cacheline_end = ALIGN(gpu_offset + 1, 64);
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int this_length = min(cacheline_end - gpu_offset, length);
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int swizzled_gpu_offset = gpu_offset ^ 64;
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if (is_read) {
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memcpy(cpu_vaddr + cpu_offset,
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gpu_vaddr + swizzled_gpu_offset,
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this_length);
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} else {
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memcpy(gpu_vaddr + swizzled_gpu_offset,
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cpu_vaddr + cpu_offset,
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this_length);
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}
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cpu_offset += this_length;
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gpu_offset += this_length;
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length -= this_length;
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}
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kunmap(cpu_page);
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kunmap(gpu_page);
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}
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/**
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* This is the fast shmem pread path, which attempts to copy_from_user directly
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* from the backing pages of the object to the user's address space. On a
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@ -386,6 +319,32 @@ i915_gem_shmem_pread_fast(struct drm_device *dev,
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return 0;
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}
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static inline int
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__copy_to_user_swizzled(char __user *cpu_vaddr,
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const char *gpu_vaddr, int gpu_offset,
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int length)
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{
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int ret, cpu_offset = 0;
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while (length > 0) {
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int cacheline_end = ALIGN(gpu_offset + 1, 64);
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int this_length = min(cacheline_end - gpu_offset, length);
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int swizzled_gpu_offset = gpu_offset ^ 64;
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ret = __copy_to_user(cpu_vaddr + cpu_offset,
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gpu_vaddr + swizzled_gpu_offset,
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this_length);
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if (ret)
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return ret + length;
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cpu_offset += this_length;
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gpu_offset += this_length;
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length -= this_length;
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}
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return 0;
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}
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static inline int
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__copy_from_user_swizzled(char __user *gpu_vaddr, int gpu_offset,
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const char *cpu_vaddr,
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@ -425,72 +384,34 @@ i915_gem_shmem_pread_slow(struct drm_device *dev,
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struct drm_file *file)
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{
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struct address_space *mapping = obj->base.filp->f_path.dentry->d_inode->i_mapping;
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struct mm_struct *mm = current->mm;
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struct page **user_pages;
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char __user *user_data;
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ssize_t remain;
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loff_t offset, pinned_pages, i;
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loff_t first_data_page, last_data_page, num_pages;
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int shmem_page_offset;
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int data_page_index, data_page_offset;
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int page_length;
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int ret;
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uint64_t data_ptr = args->data_ptr;
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int do_bit17_swizzling;
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loff_t offset;
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int shmem_page_offset, page_length, ret;
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int obj_do_bit17_swizzling, page_do_bit17_swizzling;
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user_data = (char __user *) (uintptr_t) args->data_ptr;
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remain = args->size;
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/* Pin the user pages containing the data. We can't fault while
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* holding the struct mutex, yet we want to hold it while
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* dereferencing the user data.
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*/
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first_data_page = data_ptr / PAGE_SIZE;
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last_data_page = (data_ptr + args->size - 1) / PAGE_SIZE;
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num_pages = last_data_page - first_data_page + 1;
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user_pages = drm_malloc_ab(num_pages, sizeof(struct page *));
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if (user_pages == NULL)
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return -ENOMEM;
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mutex_unlock(&dev->struct_mutex);
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down_read(&mm->mmap_sem);
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pinned_pages = get_user_pages(current, mm, (uintptr_t)args->data_ptr,
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num_pages, 1, 0, user_pages, NULL);
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up_read(&mm->mmap_sem);
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mutex_lock(&dev->struct_mutex);
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if (pinned_pages < num_pages) {
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ret = -EFAULT;
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goto out;
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}
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ret = i915_gem_object_set_cpu_read_domain_range(obj,
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args->offset,
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args->size);
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if (ret)
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goto out;
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do_bit17_swizzling = i915_gem_object_needs_bit17_swizzle(obj);
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obj_do_bit17_swizzling = i915_gem_object_needs_bit17_swizzle(obj);
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offset = args->offset;
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mutex_unlock(&dev->struct_mutex);
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while (remain > 0) {
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struct page *page;
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char *vaddr;
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/* Operation in this page
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*
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* shmem_page_offset = offset within page in shmem file
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* data_page_index = page number in get_user_pages return
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* data_page_offset = offset with data_page_index page.
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* page_length = bytes to copy for this page
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*/
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shmem_page_offset = offset_in_page(offset);
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data_page_index = data_ptr / PAGE_SIZE - first_data_page;
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data_page_offset = offset_in_page(data_ptr);
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page_length = remain;
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if ((shmem_page_offset + page_length) > PAGE_SIZE)
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page_length = PAGE_SIZE - shmem_page_offset;
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if ((data_page_offset + page_length) > PAGE_SIZE)
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page_length = PAGE_SIZE - data_page_offset;
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page = shmem_read_mapping_page(mapping, offset >> PAGE_SHIFT);
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if (IS_ERR(page)) {
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@ -498,36 +419,38 @@ i915_gem_shmem_pread_slow(struct drm_device *dev,
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goto out;
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}
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if (do_bit17_swizzling) {
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slow_shmem_bit17_copy(page,
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shmem_page_offset,
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user_pages[data_page_index],
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data_page_offset,
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page_length,
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1);
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} else {
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slow_shmem_copy(user_pages[data_page_index],
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data_page_offset,
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page,
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shmem_page_offset,
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page_length);
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}
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page_do_bit17_swizzling = obj_do_bit17_swizzling &&
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(page_to_phys(page) & (1 << 17)) != 0;
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vaddr = kmap(page);
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if (page_do_bit17_swizzling)
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ret = __copy_to_user_swizzled(user_data,
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vaddr, shmem_page_offset,
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page_length);
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else
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ret = __copy_to_user(user_data,
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vaddr + shmem_page_offset,
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page_length);
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kunmap(page);
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mark_page_accessed(page);
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page_cache_release(page);
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if (ret) {
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ret = -EFAULT;
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goto out;
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}
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remain -= page_length;
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data_ptr += page_length;
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user_data += page_length;
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offset += page_length;
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}
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out:
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for (i = 0; i < pinned_pages; i++) {
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SetPageDirty(user_pages[i]);
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mark_page_accessed(user_pages[i]);
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page_cache_release(user_pages[i]);
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}
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drm_free_large(user_pages);
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mutex_lock(&dev->struct_mutex);
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/* Fixup: Kill any reinstated backing storage pages */
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if (obj->madv == __I915_MADV_PURGED)
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i915_gem_object_truncate(obj);
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return ret;
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}
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