drm/i915: fix up tiling/fence reg setup on i8xx class hw

This fixes all the tiling problems with the 2d ddx. glxgears still doesn't work.
Changes:

- fix a copy&paste error in i8xx fence reg setup. It resulted in an at most a
  512KB offset of the fence reg window, so was only visible sometimes.
- add tests for stride and object size constrains (also for i915 and 1965 class
  hw). Userspace seems to have an of-by-one bug there, which changes the fence
  size by at most 512KB due to an overflow.
- because i8xx hw is quite old (and therefore not as well-tested) I left 2 debug
  WARN_ONs in the i8xx fence reg setup code to hopefully catch any further
  overflows in the bit-fields. Lastly there's one small change to make the
  alignment checks more consistent.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=20289
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Eric Anholt <eric@anholt.net>

drivers/gpu/drm/i915/i915_gem.c

@@ -1990,20 +1990,23 @@ static void i830_write_fence_reg(struct drm_i915_fence_reg *reg)
 	int regnum = obj_priv->fence_reg;
 	uint32_t val;
 	uint32_t pitch_val;
+	uint32_t fence_size_bits;
 
-	if ((obj_priv->gtt_offset & ~I915_FENCE_START_MASK) ||
+	if ((obj_priv->gtt_offset & ~I830_FENCE_START_MASK) ||
 	    (obj_priv->gtt_offset & (obj->size - 1))) {
-		WARN(1, "%s: object 0x%08x not 1M or size aligned\n",
+		WARN(1, "%s: object 0x%08x not 512K or size aligned\n",
 		     __func__, obj_priv->gtt_offset);
 		return;
 	}
 
 	pitch_val = (obj_priv->stride / 128) - 1;
-
+	WARN_ON(pitch_val & ~0x0000000f);
 	val = obj_priv->gtt_offset;
 	if (obj_priv->tiling_mode == I915_TILING_Y)
 		val |= 1 << I830_FENCE_TILING_Y_SHIFT;
-	val |= I830_FENCE_SIZE_BITS(obj->size);
+	fence_size_bits = I830_FENCE_SIZE_BITS(obj->size);
+	WARN_ON(fence_size_bits & ~0x00000f00);
+	val |= fence_size_bits;
 	val |= pitch_val << I830_FENCE_PITCH_SHIFT;
 	val |= I830_FENCE_REG_VALID;
 
@@ -2194,7 +2197,7 @@ i915_gem_object_bind_to_gtt(struct drm_gem_object *obj, unsigned alignment)
 		return -EBUSY;
 	if (alignment == 0)
 		alignment = i915_gem_get_gtt_alignment(obj);
-	if (alignment & (PAGE_SIZE - 1)) {
+	if (alignment & (i915_gem_get_gtt_alignment(obj) - 1)) {
 		DRM_ERROR("Invalid object alignment requested %u\n", alignment);
 		return -EINVAL;
 	}

drivers/gpu/drm/i915/i915_gem_tiling.c

@@ -216,6 +216,22 @@ i915_tiling_ok(struct drm_device *dev, int stride, int size, int tiling_mode)
 	else
 		tile_width = 512;
 
+	/* check maximum stride & object size */
+	if (IS_I965G(dev)) {
+		/* i965 stores the end address of the gtt mapping in the fence
+		 * reg, so dont bother to check the size */
+		if (stride / 128 > I965_FENCE_MAX_PITCH_VAL)
+			return false;
+	} else if (IS_I9XX(dev)) {
+		if (stride / tile_width > I830_FENCE_MAX_PITCH_VAL ||
+		    size > (I830_FENCE_MAX_SIZE_VAL << 20))
+			return false;
+	} else {
+		if (stride / 128 > I830_FENCE_MAX_PITCH_VAL ||
+		    size > (I830_FENCE_MAX_SIZE_VAL << 19))
+			return false;
+	}
+
 	/* 965+ just needs multiples of tile width */
 	if (IS_I965G(dev)) {
 		if (stride & (tile_width - 1))

drivers/gpu/drm/i915/i915_reg.h

@@ -190,6 +190,8 @@
 #define   I830_FENCE_SIZE_BITS(size)	((ffs((size) >> 19) - 1) << 8)
 #define   I830_FENCE_PITCH_SHIFT	4
 #define   I830_FENCE_REG_VALID		(1<<0)
+#define   I830_FENCE_MAX_PITCH_VAL	0x10
+#define   I830_FENCE_MAX_SIZE_VAL	(1<<8)
 
 #define   I915_FENCE_START_MASK		0x0ff00000
 #define   I915_FENCE_SIZE_BITS(size)	((ffs((size) >> 20) - 1) << 8)
@@ -198,6 +200,7 @@
 #define   I965_FENCE_PITCH_SHIFT	2
 #define   I965_FENCE_TILING_Y_SHIFT	1
 #define   I965_FENCE_REG_VALID		(1<<0)
+#define   I965_FENCE_MAX_PITCH_VAL	0x0400
 
 /*
  * Instruction and interrupt control regs