i965: Tell intel_get_memcpy() which direction the memcpy() is going.

The SSSE3 swizzling code was written for fast uploads to the GPU and
assumed the destination was always 16-byte aligned. When we began using
this code for fast downloads as well we didn't do anything to account
for the fact that the destination pointer given by glReadPixels() or
glGetTexImage() is not guaranteed to be suitably aligned.

With SSSE3 enabled (at compile-time), some applications would crash when
an SSE aligned-store instruction tried to store to an unaligned
destination (or an assertion that the destination is aligned would
trigger).

To remedy this, tell intel_get_memcpy() whether we're uploading or
downloading so that it can select whether to assume the destination or
source is aligned, respectively.

Cc: 10.5 <mesa-stable@lists.freedesktop.org>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=89416
Tested-by: Uriy Zhuravlev <stalkerg@gmail.com>
Reviewed-by: Jason Ekstrand <jason.ekstrand@intel.com>
(cherry picked from commit 2e4c95dfe2cb205c327ceaa12b44a9273bdb20dc)

5 files changed, 106 insertions, 42 deletions

diff --git a/src/mesa/drivers/dri/i965/intel_pixel_read.c b/src/mesa/drivers/dri/i965/intel_pixel_read.c
index df22a637dce..09721211fa4 100644
--- a/src/mesa/drivers/dri/i965/intel_pixel_read.c
+++ b/src/mesa/drivers/dri/i965/intel_pixel_read.c
@@ -139,7 +139,8 @@ intel_readpixels_tiled_memcpy(struct gl_context * ctx,
        rb->Format == MESA_FORMAT_R8G8B8X8_UNORM)
       return false;
 
-   if (!intel_get_memcpy(rb->Format, format, type, &mem_copy, &cpp))
+   if (!intel_get_memcpy(rb->Format, format, type, &mem_copy, &cpp,
+                         INTEL_DOWNLOAD))
       return false;
 
    if (!irb->mt ||
diff --git a/src/mesa/drivers/dri/i965/intel_tex_image.c b/src/mesa/drivers/dri/i965/intel_tex_image.c
index 6eebfc4bd4b..d18e0bf5bb9 100644
--- a/src/mesa/drivers/dri/i965/intel_tex_image.c
+++ b/src/mesa/drivers/dri/i965/intel_tex_image.c
@@ -399,7 +399,8 @@ intel_gettexsubimage_tiled_memcpy(struct gl_context *ctx,
        texImage->TexFormat == MESA_FORMAT_R8G8B8X8_UNORM)
       return false;
 
-   if (!intel_get_memcpy(texImage->TexFormat, format, type, &mem_copy, &cpp))
+   if (!intel_get_memcpy(texImage->TexFormat, format, type, &mem_copy, &cpp,
+                         INTEL_DOWNLOAD))
       return false;
 
    /* If this is a nontrivial texture view, let another path handle it instead. */
diff --git a/src/mesa/drivers/dri/i965/intel_tex_subimage.c b/src/mesa/drivers/dri/i965/intel_tex_subimage.c
index 4262f71ff4f..909ff25d825 100644
--- a/src/mesa/drivers/dri/i965/intel_tex_subimage.c
+++ b/src/mesa/drivers/dri/i965/intel_tex_subimage.c
@@ -118,7 +118,8 @@ intel_texsubimage_tiled_memcpy(struct gl_context * ctx,
        packing->Invert)
       return false;
 
-   if (!intel_get_memcpy(texImage->TexFormat, format, type, &mem_copy, &cpp))
+   if (!intel_get_memcpy(texImage->TexFormat, format, type, &mem_copy, &cpp,
+                         INTEL_UPLOAD))
       return false;
 
    /* If this is a nontrivial texture view, let another path handle it instead. */
diff --git a/src/mesa/drivers/dri/i965/intel_tiled_memcpy.c b/src/mesa/drivers/dri/i965/intel_tiled_memcpy.c
index f2b35cb01d3..2097aaa2d4d 100644
--- a/src/mesa/drivers/dri/i965/intel_tiled_memcpy.c
+++ b/src/mesa/drivers/dri/i965/intel_tiled_memcpy.c
@@ -60,42 +60,79 @@ static const uint32_t ytile_span = 16;
 static const uint8_t rgba8_permutation[16] =
    { 2,1,0,3, 6,5,4,7, 10,9,8,11, 14,13,12,15 };
 
-/* NOTE: dst must be 16 byte aligned */
-#define rgba8_copy_16(dst, src)                     \
-   *(__m128i *)(dst) = _mm_shuffle_epi8(            \
-      (__m128i) _mm_loadu_ps((float *)(src)),       \
-      *(__m128i *) rgba8_permutation                \
-   )
+/* NOTE: dst must be 16-byte aligned. src may be unaligned. */
+#define rgba8_copy_16_aligned_dst(dst, src)                            \
+   _mm_store_si128((__m128i *)(dst),                                   \
+                   _mm_shuffle_epi8(_mm_loadu_si128((__m128i *)(src)), \
+                                    *(__m128i *) rgba8_permutation))
+
+/* NOTE: src must be 16-byte aligned. dst may be unaligned. */
+#define rgba8_copy_16_aligned_src(dst, src)                            \
+   _mm_storeu_si128((__m128i *)(dst),                                  \
+                    _mm_shuffle_epi8(_mm_load_si128((__m128i *)(src)), \
+                                     *(__m128i *) rgba8_permutation))
 #endif
 
 /**
- * Copy RGBA to BGRA - swap R and B.
+ * Copy RGBA to BGRA - swap R and B, with the destination 16-byte aligned.
  */
 static inline void *
-rgba8_copy(void *dst, const void *src, size_t bytes)
+rgba8_copy_aligned_dst(void *dst, const void *src, size_t bytes)
 {
    uint8_t *d = dst;
    uint8_t const *s = src;
 
 #ifdef __SSSE3__
-   /* Fast copying for tile spans.
-    *
-    * As long as the destination texture is 16 aligned,
-    * any 16 or 64 spans we get here should also be 16 aligned.
-    */
-
    if (bytes == 16) {
       assert(!(((uintptr_t)dst) & 0xf));
-      rgba8_copy_16(d+ 0, s+ 0);
+      rgba8_copy_16_aligned_dst(d+ 0, s+ 0);
       return dst;
    }
 
    if (bytes == 64) {
       assert(!(((uintptr_t)dst) & 0xf));
-      rgba8_copy_16(d+ 0, s+ 0);
-      rgba8_copy_16(d+16, s+16);
-      rgba8_copy_16(d+32, s+32);
-      rgba8_copy_16(d+48, s+48);
+      rgba8_copy_16_aligned_dst(d+ 0, s+ 0);
+      rgba8_copy_16_aligned_dst(d+16, s+16);
+      rgba8_copy_16_aligned_dst(d+32, s+32);
+      rgba8_copy_16_aligned_dst(d+48, s+48);
+      return dst;
+   }
+#endif
+
+   while (bytes >= 4) {
+      d[0] = s[2];
+      d[1] = s[1];
+      d[2] = s[0];
+      d[3] = s[3];
+      d += 4;
+      s += 4;
+      bytes -= 4;
+   }
+   return dst;
+}
+
+/**
+ * Copy RGBA to BGRA - swap R and B, with the source 16-byte aligned.
+ */
+static inline void *
+rgba8_copy_aligned_src(void *dst, const void *src, size_t bytes)
+{
+   uint8_t *d = dst;
+   uint8_t const *s = src;
+
+#ifdef __SSSE3__
+   if (bytes == 16) {
+      assert(!(((uintptr_t)src) & 0xf));
+      rgba8_copy_16_aligned_src(d+ 0, s+ 0);
+      return dst;
+   }
+
+   if (bytes == 64) {
+      assert(!(((uintptr_t)src) & 0xf));
+      rgba8_copy_16_aligned_src(d+ 0, s+ 0);
+      rgba8_copy_16_aligned_src(d+16, s+16);
+      rgba8_copy_16_aligned_src(d+32, s+32);
+      rgba8_copy_16_aligned_src(d+48, s+48);
       return dst;
    }
 #endif
@@ -357,16 +394,18 @@ linear_to_xtiled_faster(uint32_t x0, uint32_t x1, uint32_t x2, uint32_t x3,
       if (mem_copy == memcpy)
          return linear_to_xtiled(0, 0, xtile_width, xtile_width, 0, xtile_height,
                                  dst, src, src_pitch, swizzle_bit, memcpy);
-      else if (mem_copy == rgba8_copy)
+      else if (mem_copy == rgba8_copy_aligned_dst)
          return linear_to_xtiled(0, 0, xtile_width, xtile_width, 0, xtile_height,
-                                 dst, src, src_pitch, swizzle_bit, rgba8_copy);
+                                 dst, src, src_pitch, swizzle_bit,
+                                 rgba8_copy_aligned_dst);
    } else {
       if (mem_copy == memcpy)
          return linear_to_xtiled(x0, x1, x2, x3, y0, y1,
                                  dst, src, src_pitch, swizzle_bit, memcpy);
-      else if (mem_copy == rgba8_copy)
+      else if (mem_copy == rgba8_copy_aligned_dst)
          return linear_to_xtiled(x0, x1, x2, x3, y0, y1,
-                                 dst, src, src_pitch, swizzle_bit, rgba8_copy);
+                                 dst, src, src_pitch, swizzle_bit,
+                                 rgba8_copy_aligned_dst);
    }
    linear_to_xtiled(x0, x1, x2, x3, y0, y1,
                     dst, src, src_pitch, swizzle_bit, mem_copy);
@@ -393,16 +432,18 @@ linear_to_ytiled_faster(uint32_t x0, uint32_t x1, uint32_t x2, uint32_t x3,
       if (mem_copy == memcpy)
          return linear_to_ytiled(0, 0, ytile_width, ytile_width, 0, ytile_height,
                                  dst, src, src_pitch, swizzle_bit, memcpy);
-      else if (mem_copy == rgba8_copy)
+      else if (mem_copy == rgba8_copy_aligned_dst)
          return linear_to_ytiled(0, 0, ytile_width, ytile_width, 0, ytile_height,
-                                 dst, src, src_pitch, swizzle_bit, rgba8_copy);
+                                 dst, src, src_pitch, swizzle_bit,
+                                 rgba8_copy_aligned_dst);
    } else {
       if (mem_copy == memcpy)
          return linear_to_ytiled(x0, x1, x2, x3, y0, y1,
                                  dst, src, src_pitch, swizzle_bit, memcpy);
-      else if (mem_copy == rgba8_copy)
+      else if (mem_copy == rgba8_copy_aligned_dst)
          return linear_to_ytiled(x0, x1, x2, x3, y0, y1,
-                                 dst, src, src_pitch, swizzle_bit, rgba8_copy);
+                                 dst, src, src_pitch, swizzle_bit,
+                                 rgba8_copy_aligned_dst);
    }
    linear_to_ytiled(x0, x1, x2, x3, y0, y1,
                     dst, src, src_pitch, swizzle_bit, mem_copy);
@@ -429,16 +470,18 @@ xtiled_to_linear_faster(uint32_t x0, uint32_t x1, uint32_t x2, uint32_t x3,
       if (mem_copy == memcpy)
          return xtiled_to_linear(0, 0, xtile_width, xtile_width, 0, xtile_height,
                                  dst, src, dst_pitch, swizzle_bit, memcpy);
-      else if (mem_copy == rgba8_copy)
+      else if (mem_copy == rgba8_copy_aligned_src)
          return xtiled_to_linear(0, 0, xtile_width, xtile_width, 0, xtile_height,
-                                 dst, src, dst_pitch, swizzle_bit, rgba8_copy);
+                                 dst, src, dst_pitch, swizzle_bit,
+                                 rgba8_copy_aligned_src);
    } else {
       if (mem_copy == memcpy)
          return xtiled_to_linear(x0, x1, x2, x3, y0, y1,
                                  dst, src, dst_pitch, swizzle_bit, memcpy);
-      else if (mem_copy == rgba8_copy)
+      else if (mem_copy == rgba8_copy_aligned_src)
          return xtiled_to_linear(x0, x1, x2, x3, y0, y1,
-                                 dst, src, dst_pitch, swizzle_bit, rgba8_copy);
+                                 dst, src, dst_pitch, swizzle_bit,
+                                 rgba8_copy_aligned_src);
    }
    xtiled_to_linear(x0, x1, x2, x3, y0, y1,
                     dst, src, dst_pitch, swizzle_bit, mem_copy);
@@ -465,16 +508,18 @@ ytiled_to_linear_faster(uint32_t x0, uint32_t x1, uint32_t x2, uint32_t x3,
       if (mem_copy == memcpy)
          return ytiled_to_linear(0, 0, ytile_width, ytile_width, 0, ytile_height,
                                  dst, src, dst_pitch, swizzle_bit, memcpy);
-      else if (mem_copy == rgba8_copy)
+      else if (mem_copy == rgba8_copy_aligned_src)
          return ytiled_to_linear(0, 0, ytile_width, ytile_width, 0, ytile_height,
-                                 dst, src, dst_pitch, swizzle_bit, rgba8_copy);
+                                 dst, src, dst_pitch, swizzle_bit,
+                                 rgba8_copy_aligned_src);
    } else {
       if (mem_copy == memcpy)
          return ytiled_to_linear(x0, x1, x2, x3, y0, y1,
                                  dst, src, dst_pitch, swizzle_bit, memcpy);
-      else if (mem_copy == rgba8_copy)
+      else if (mem_copy == rgba8_copy_aligned_src)
          return ytiled_to_linear(x0, x1, x2, x3, y0, y1,
-                                 dst, src, dst_pitch, swizzle_bit, rgba8_copy);
+                                 dst, src, dst_pitch, swizzle_bit,
+                                 rgba8_copy_aligned_src);
    }
    ytiled_to_linear(x0, x1, x2, x3, y0, y1,
                     dst, src, dst_pitch, swizzle_bit, mem_copy);
@@ -684,7 +729,8 @@ tiled_to_linear(uint32_t xt1, uint32_t xt2,
  * \return true if the format and type combination are valid
  */
 bool intel_get_memcpy(mesa_format tiledFormat, GLenum format,
-                      GLenum type, mem_copy_fn* mem_copy, uint32_t* cpp)
+                      GLenum type, mem_copy_fn *mem_copy, uint32_t *cpp,
+                      enum intel_memcpy_direction direction)
 {
    if (type == GL_UNSIGNED_INT_8_8_8_8_REV &&
        !(format == GL_RGBA || format == GL_BGRA))
@@ -700,7 +746,8 @@ bool intel_get_memcpy(mesa_format tiledFormat, GLenum format,
       if (format == GL_BGRA) {
          *mem_copy = memcpy;
       } else if (format == GL_RGBA) {
-         *mem_copy = rgba8_copy;
+         *mem_copy = direction == INTEL_UPLOAD ? rgba8_copy_aligned_dst
+                                               : rgba8_copy_aligned_src;
       }
    } else if ((tiledFormat == MESA_FORMAT_R8G8B8A8_UNORM) ||
               (tiledFormat == MESA_FORMAT_R8G8B8X8_UNORM)) {
@@ -709,7 +756,8 @@ bool intel_get_memcpy(mesa_format tiledFormat, GLenum format,
          /* Copying from RGBA to BGRA is the same as BGRA to RGBA so we can
           * use the same function.
           */
-         *mem_copy = rgba8_copy;
+         *mem_copy = direction == INTEL_UPLOAD ? rgba8_copy_aligned_dst
+                                               : rgba8_copy_aligned_src;
       } else if (format == GL_RGBA) {
          *mem_copy = memcpy;
       }
diff --git a/src/mesa/drivers/dri/i965/intel_tiled_memcpy.h b/src/mesa/drivers/dri/i965/intel_tiled_memcpy.h
index 3ff0d712765..9dc1088d25c 100644
--- a/src/mesa/drivers/dri/i965/intel_tiled_memcpy.h
+++ b/src/mesa/drivers/dri/i965/intel_tiled_memcpy.h
@@ -55,7 +55,20 @@ tiled_to_linear(uint32_t xt1, uint32_t xt2,
                 uint32_t tiling,
                 mem_copy_fn mem_copy);
 
+/* Tells intel_get_memcpy() whether the memcpy() is
+ *
+ *  - an upload to the GPU with an aligned destination and a potentially
+ *    unaligned source; or
+ *  - a download from the GPU with an aligned source and a potentially
+ *    unaligned destination.
+ */
+enum intel_memcpy_direction {
+   INTEL_UPLOAD,
+   INTEL_DOWNLOAD
+};
+
 bool intel_get_memcpy(mesa_format tiledFormat, GLenum format,
-                      GLenum type, mem_copy_fn* mem_copy, uint32_t* cpp);
+                      GLenum type, mem_copy_fn *mem_copy, uint32_t *cpp,
+                      enum intel_memcpy_direction direction);
 
 #endif /* INTEL_TILED_MEMCPY */