* we would try to acquire the struct mutex again. Obviously
* this is bad and so lockdep complains vehemently.
*/
- pagefault_disable();
- copied = __copy_from_user_inatomic(r, urelocs, count * sizeof(r[0]));
- pagefault_enable();
+ copied = __copy_from_user(r, urelocs, count * sizeof(r[0]));
if (unlikely(copied)) {
remain = -EFAULT;
goto out;
return remain;
}
-static int
-eb_relocate_vma_slow(struct i915_execbuffer *eb, struct eb_vma *ev)
-{
- const struct drm_i915_gem_exec_object2 *entry = ev->exec;
- struct drm_i915_gem_relocation_entry *relocs =
- u64_to_ptr(typeof(*relocs), entry->relocs_ptr);
- unsigned int i;
- int err;
-
- for (i = 0; i < entry->relocation_count; i++) {
- u64 offset = eb_relocate_entry(eb, ev, &relocs[i]);
-
- if ((s64)offset < 0) {
- err = (int)offset;
- goto err;
- }
- }
- err = 0;
-err:
- reloc_cache_reset(&eb->reloc_cache);
- return err;
-}
-
-static int check_relocations(const struct drm_i915_gem_exec_object2 *entry)
-{
- const char __user *addr, *end;
- unsigned long size;
- char __maybe_unused c;
-
- size = entry->relocation_count;
- if (size == 0)
- return 0;
-
- if (size > N_RELOC(ULONG_MAX))
- return -EINVAL;
-
- addr = u64_to_user_ptr(entry->relocs_ptr);
- size *= sizeof(struct drm_i915_gem_relocation_entry);
- if (!access_ok(addr, size))
- return -EFAULT;
-
- end = addr + size;
- for (; addr < end; addr += PAGE_SIZE) {
- int err = __get_user(c, addr);
- if (err)
- return err;
- }
- return __get_user(c, end - 1);
-}
-
-static int eb_copy_relocations(const struct i915_execbuffer *eb)
-{
- struct drm_i915_gem_relocation_entry *relocs;
- const unsigned int count = eb->buffer_count;
- unsigned int i;
- int err;
-
- for (i = 0; i < count; i++) {
- const unsigned int nreloc = eb->exec[i].relocation_count;
- struct drm_i915_gem_relocation_entry __user *urelocs;
- unsigned long size;
- unsigned long copied;
-
- if (nreloc == 0)
- continue;
-
- err = check_relocations(&eb->exec[i]);
- if (err)
- goto err;
-
- urelocs = u64_to_user_ptr(eb->exec[i].relocs_ptr);
- size = nreloc * sizeof(*relocs);
-
- relocs = kvmalloc_array(size, 1, GFP_KERNEL);
- if (!relocs) {
- err = -ENOMEM;
- goto err;
- }
-
- /* copy_from_user is limited to < 4GiB */
- copied = 0;
- do {
- unsigned int len =
- min_t(u64, BIT_ULL(31), size - copied);
-
- if (__copy_from_user((char *)relocs + copied,
- (char __user *)urelocs + copied,
- len))
- goto end;
-
- copied += len;
- } while (copied < size);
-
- /*
- * As we do not update the known relocation offsets after
- * relocating (due to the complexities in lock handling),
- * we need to mark them as invalid now so that we force the
- * relocation processing next time. Just in case the target
- * object is evicted and then rebound into its old
- * presumed_offset before the next execbuffer - if that
- * happened we would make the mistake of assuming that the
- * relocations were valid.
- */
- if (!user_access_begin(urelocs, size))
- goto end;
-
- for (copied = 0; copied < nreloc; copied++)
- unsafe_put_user(-1,
- &urelocs[copied].presumed_offset,
- end_user);
- user_access_end();
-
- eb->exec[i].relocs_ptr = (uintptr_t)relocs;
- }
-
- return 0;
-
-end_user:
- user_access_end();
-end:
- kvfree(relocs);
- err = -EFAULT;
-err:
- while (i--) {
- relocs = u64_to_ptr(typeof(*relocs), eb->exec[i].relocs_ptr);
- if (eb->exec[i].relocation_count)
- kvfree(relocs);
- }
- return err;
-}
-
-static int eb_prefault_relocations(const struct i915_execbuffer *eb)
-{
- const unsigned int count = eb->buffer_count;
- unsigned int i;
-
- for (i = 0; i < count; i++) {
- int err;
-
- err = check_relocations(&eb->exec[i]);
- if (err)
- return err;
- }
-
- return 0;
-}
-
-static noinline int eb_relocate_slow(struct i915_execbuffer *eb)
-{
- bool have_copy = false;
- struct eb_vma *ev;
- int err = 0;
-
-repeat:
- if (signal_pending(current)) {
- err = -ERESTARTSYS;
- goto out;
- }
-
- /*
- * We take 3 passes through the slowpatch.
- *
- * 1 - we try to just prefault all the user relocation entries and
- * then attempt to reuse the atomic pagefault disabled fast path again.
- *
- * 2 - we copy the user entries to a local buffer here outside of the
- * local and allow ourselves to wait upon any rendering before
- * relocations
- *
- * 3 - we already have a local copy of the relocation entries, but
- * were interrupted (EAGAIN) whilst waiting for the objects, try again.
- */
- if (!err) {
- err = eb_prefault_relocations(eb);
- } else if (!have_copy) {
- err = eb_copy_relocations(eb);
- have_copy = err == 0;
- } else {
- cond_resched();
- err = 0;
- }
- if (err)
- goto out;
-
- list_for_each_entry(ev, &eb->relocs, reloc_link) {
- if (!have_copy) {
- pagefault_disable();
- err = eb_relocate_vma(eb, ev);
- pagefault_enable();
- if (err)
- goto repeat;
- } else {
- err = eb_relocate_vma_slow(eb, ev);
- if (err)
- goto err;
- }
- }
-
- /*
- * Leave the user relocations as are, this is the painfully slow path,
- * and we want to avoid the complication of dropping the lock whilst
- * having buffers reserved in the aperture and so causing spurious
- * ENOSPC for random operations.
- */
-
-err:
- if (err == -EAGAIN)
- goto repeat;
-
-out:
- if (have_copy) {
- const unsigned int count = eb->buffer_count;
- unsigned int i;
-
- for (i = 0; i < count; i++) {
- const struct drm_i915_gem_exec_object2 *entry =
- &eb->exec[i];
- struct drm_i915_gem_relocation_entry *relocs;
-
- if (!entry->relocation_count)
- continue;
-
- relocs = u64_to_ptr(typeof(*relocs), entry->relocs_ptr);
- kvfree(relocs);
- }
- }
-
- return err;
-}
-
static int eb_relocate(struct i915_execbuffer *eb)
{
int err;
struct eb_vma *ev;
list_for_each_entry(ev, &eb->relocs, reloc_link) {
- if (eb_relocate_vma(eb, ev))
- return eb_relocate_slow(eb);
+ err = eb_relocate_vma(eb, ev);
+ if (err)
+ return err;
}
}
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