drm/i915: Drop I915_CONTEXT_PARAM_NO_ZEROMAP

The idea behind this param is to support OpenCL drivers with relocations
because OpenCL reserves 0x0 for NULL and, if we placed memory there, it
would confuse CL kernels.  It was originally sent out as part of a patch
series including libdrm [1] and Beignet [2] support.  However, the
libdrm and Beignet patches never landed in their respective upstream
projects so this API has never been used.  It's never been used in Mesa
or any other driver, either.

Dropping this API allows us to delete a small bit of code.

[1]: https://lists.freedesktop.org/archives/intel-gfx/2015-May/067030.html
[2]: https://lists.freedesktop.org/archives/intel-gfx/2015-May/067031.htmlSigned-off-by: Jason Ekstrand <jason@jlekstrand.net>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20210708154835.528166-4-jason@jlekstrand.net

drivers/gpu/drm/i915/gem/i915_gem_context.c

@@ -1920,15 +1920,6 @@ static int ctx_setparam(struct drm_i915_file_private *fpriv,
 	int ret = 0;
 
 	switch (args->param) {
-	case I915_CONTEXT_PARAM_NO_ZEROMAP:
-		if (args->size)
-			ret = -EINVAL;
-		else if (args->value)
-			set_bit(UCONTEXT_NO_ZEROMAP, &ctx->user_flags);
-		else
-			clear_bit(UCONTEXT_NO_ZEROMAP, &ctx->user_flags);
-		break;
-
 	case I915_CONTEXT_PARAM_NO_ERROR_CAPTURE:
 		if (args->size)
 			ret = -EINVAL;
@@ -1978,6 +1969,7 @@ static int ctx_setparam(struct drm_i915_file_private *fpriv,
 		ret = set_persistence(ctx, args);
 		break;
 
+	case I915_CONTEXT_PARAM_NO_ZEROMAP:
 	case I915_CONTEXT_PARAM_BAN_PERIOD:
 	case I915_CONTEXT_PARAM_RINGSIZE:
 	default:
@@ -2358,11 +2350,6 @@ int i915_gem_context_getparam_ioctl(struct drm_device *dev, void *data,
 		return -ENOENT;
 
 	switch (args->param) {
-	case I915_CONTEXT_PARAM_NO_ZEROMAP:
-		args->size = 0;
-		args->value = test_bit(UCONTEXT_NO_ZEROMAP, &ctx->user_flags);
-		break;
-
 	case I915_CONTEXT_PARAM_GTT_SIZE:
 		args->size = 0;
 		rcu_read_lock();
@@ -2410,6 +2397,7 @@ int i915_gem_context_getparam_ioctl(struct drm_device *dev, void *data,
 		args->value = i915_gem_context_is_persistent(ctx);
 		break;
 
+	case I915_CONTEXT_PARAM_NO_ZEROMAP:
 	case I915_CONTEXT_PARAM_BAN_PERIOD:
 	case I915_CONTEXT_PARAM_RINGSIZE:
 	default:

drivers/gpu/drm/i915/gem/i915_gem_context_types.h

@@ -129,7 +129,6 @@ struct i915_gem_context {
 	 * @user_flags: small set of booleans controlled by the user
 	 */
 	unsigned long user_flags;
-#define UCONTEXT_NO_ZEROMAP		0
 #define UCONTEXT_NO_ERROR_CAPTURE	1
 #define UCONTEXT_BANNABLE		2
 #define UCONTEXT_RECOVERABLE		3

drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c

@@ -290,7 +290,6 @@ struct i915_execbuffer {
 	struct intel_context *reloc_context;
 
 	u64 invalid_flags; /** Set of execobj.flags that are invalid */
-	u32 context_flags; /** Set of execobj.flags to insert from the ctx */
 
 	u64 batch_len; /** Length of batch within object */
 	u32 batch_start_offset; /** Location within object of batch */
@@ -541,9 +540,6 @@ eb_validate_vma(struct i915_execbuffer *eb,
 			entry->flags |= EXEC_OBJECT_NEEDS_GTT | __EXEC_OBJECT_NEEDS_MAP;
 	}
 
-	if (!(entry->flags & EXEC_OBJECT_PINNED))
-		entry->flags |= eb->context_flags;
-
 	return 0;
 }
 
@@ -750,10 +746,6 @@ static int eb_select_context(struct i915_execbuffer *eb)
 	if (rcu_access_pointer(ctx->vm))
 		eb->invalid_flags |= EXEC_OBJECT_NEEDS_GTT;
 
-	eb->context_flags = 0;
-	if (test_bit(UCONTEXT_NO_ZEROMAP, &ctx->user_flags))
-		eb->context_flags |= __EXEC_OBJECT_NEEDS_BIAS;
-
 	return 0;
 }
 

include/uapi/drm/i915_drm.h

@@ -1638,6 +1638,10 @@ struct drm_i915_gem_context_param {
 	__u32 size;
 	__u64 param;
 #define I915_CONTEXT_PARAM_BAN_PERIOD	0x1
+/* I915_CONTEXT_PARAM_NO_ZEROMAP has been removed.  On the off chance
+ * someone somewhere has attempted to use it, never re-use this context
+ * param number.
+ */
 #define I915_CONTEXT_PARAM_NO_ZEROMAP	0x2
 #define I915_CONTEXT_PARAM_GTT_SIZE	0x3
 #define I915_CONTEXT_PARAM_NO_ERROR_CAPTURE	0x4