[Intel-gfx] [PATCH 5/8] drm/i915: Align start for memcpy_from_wc
Chris Wilson
chris at chris-wilson.co.uk
Sat Dec 7 17:01:07 UTC 2019
The movntqda requires 16-byte alignment for the source pointer. Avoid
falling back to clflush if the source pointer is misaligned by doing the
doing a small uncached memcpy to fixup the alignments.
Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
---
drivers/gpu/drm/i915/i915_cmd_parser.c | 30 +++++++++++++++++---------
1 file changed, 20 insertions(+), 10 deletions(-)
diff --git a/drivers/gpu/drm/i915/i915_cmd_parser.c b/drivers/gpu/drm/i915/i915_cmd_parser.c
index 6cf4e336461b..2977316d64ae 100644
--- a/drivers/gpu/drm/i915/i915_cmd_parser.c
+++ b/drivers/gpu/drm/i915/i915_cmd_parser.c
@@ -1132,8 +1132,8 @@ static u32 *copy_batch(struct drm_i915_gem_object *dst_obj,
{
unsigned int src_needs_clflush;
unsigned int dst_needs_clflush;
- void *dst, *src;
- int ret;
+ void *dst, *src, *ptr;
+ int ret, len;
ret = i915_gem_object_prepare_write(dst_obj, &dst_needs_clflush);
if (ret)
@@ -1150,19 +1150,30 @@ static u32 *copy_batch(struct drm_i915_gem_object *dst_obj,
return ERR_PTR(ret);
}
+ ptr = dst;
src = ERR_PTR(-ENODEV);
- if (src_needs_clflush &&
- i915_can_memcpy_from_wc(NULL, offset, 0)) {
+ if (src_needs_clflush && i915_has_memcpy_from_wc()) {
src = i915_gem_object_pin_map(src_obj, I915_MAP_WC);
if (!IS_ERR(src)) {
- i915_memcpy_from_wc(dst,
- src + offset,
- ALIGN(length, 16));
+ src += offset;
+
+ if (!IS_ALIGNED(offset, 16)) {
+ len = min(ALIGN(offset, 16) - offset, length);
+
+ memcpy(ptr, src, len);
+
+ offset += len;
+ length -= len;
+ ptr += len;
+ src += len;
+ }
+ GEM_BUG_ON(!IS_ALIGNED((unsigned long)src, 16));
+
+ i915_memcpy_from_wc(ptr, src, ALIGN(length, 16));
i915_gem_object_unpin_map(src_obj);
}
}
if (IS_ERR(src)) {
- void *ptr;
int x, n;
/*
@@ -1177,10 +1188,9 @@ static u32 *copy_batch(struct drm_i915_gem_object *dst_obj,
length = round_up(length,
boot_cpu_data.x86_clflush_size);
- ptr = dst;
x = offset_in_page(offset);
for (n = offset >> PAGE_SHIFT; length; n++) {
- int len = min_t(int, length, PAGE_SIZE - x);
+ len = min_t(int, length, PAGE_SIZE - x);
src = kmap_atomic(i915_gem_object_get_page(src_obj, n));
if (src_needs_clflush)
--
2.24.0
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