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* [Intel-gfx] [PATCH] drm/i915: Align engine->uabi_class/instance with i915_drm.h
@ 2020-01-15 15:24 Tvrtko Ursulin
  2020-01-15 15:28 ` Tvrtko Ursulin
                   ` (7 more replies)
  0 siblings, 8 replies; 11+ messages in thread
From: Tvrtko Ursulin @ 2020-01-15 15:24 UTC (permalink / raw)
  To: Intel-gfx

From: Tvrtko Ursulin <tvrtko.ursulin@intel.com>

In our ABI we have defined I915_ENGINE_CLASS_INVALID_NONE and
I915_ENGINE_CLASS_INVALID_VIRTUAL as negative values which creates
implicit coupling with type widths used in, also ABI, struct
i915_engine_class_instance.

When for instance we export engine->uabi_class
I915_ENGINE_CLASS_INVALID_VIRTUAL from our our tracepoints, because the
type of the former is u8 in contrast to u16 defined in the ABI, 254 will
be returned instead of 65534 which userspace would legitimately expect.

Therefore we need to align the type used to store engine ABI class and
instance.

I did not find any other user visible inconsistency apart from the
tracepoints so I think importance of the fix is low.

Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
---
 drivers/gpu/drm/i915/gem/i915_gem_busy.c     | 12 ++++++------
 drivers/gpu/drm/i915/gt/intel_engine_types.h |  4 ++--
 2 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_busy.c b/drivers/gpu/drm/i915/gem/i915_gem_busy.c
index 3d4f5775a4ba..25235ef630c1 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_busy.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_busy.c
@@ -9,16 +9,16 @@
 #include "i915_gem_ioctls.h"
 #include "i915_gem_object.h"
 
-static __always_inline u32 __busy_read_flag(u8 id)
+static __always_inline u32 __busy_read_flag(u16 id)
 {
-	if (id == (u8)I915_ENGINE_CLASS_INVALID)
+	if (id == (u16)I915_ENGINE_CLASS_INVALID)
 		return 0xffff0000u;
 
 	GEM_BUG_ON(id >= 16);
 	return 0x10000u << id;
 }
 
-static __always_inline u32 __busy_write_id(u8 id)
+static __always_inline u32 __busy_write_id(u16 id)
 {
 	/*
 	 * The uABI guarantees an active writer is also amongst the read
@@ -29,14 +29,14 @@ static __always_inline u32 __busy_write_id(u8 id)
 	 * last_read - hence we always set both read and write busy for
 	 * last_write.
 	 */
-	if (id == (u8)I915_ENGINE_CLASS_INVALID)
+	if (id == (u16)I915_ENGINE_CLASS_INVALID)
 		return 0xffffffffu;
 
 	return (id + 1) | __busy_read_flag(id);
 }
 
 static __always_inline unsigned int
-__busy_set_if_active(const struct dma_fence *fence, u32 (*flag)(u8 id))
+__busy_set_if_active(const struct dma_fence *fence, u32 (*flag)(u16 id))
 {
 	const struct i915_request *rq;
 
@@ -57,7 +57,7 @@ __busy_set_if_active(const struct dma_fence *fence, u32 (*flag)(u8 id))
 		return 0;
 
 	/* Beware type-expansion follies! */
-	BUILD_BUG_ON(!typecheck(u8, rq->engine->uabi_class));
+	BUILD_BUG_ON(!typecheck(u16, rq->engine->uabi_class));
 	return flag(rq->engine->uabi_class);
 }
 
diff --git a/drivers/gpu/drm/i915/gt/intel_engine_types.h b/drivers/gpu/drm/i915/gt/intel_engine_types.h
index 00287515e7af..350da59e605b 100644
--- a/drivers/gpu/drm/i915/gt/intel_engine_types.h
+++ b/drivers/gpu/drm/i915/gt/intel_engine_types.h
@@ -278,8 +278,8 @@ struct intel_engine_cs {
 	u8 class;
 	u8 instance;
 
-	u8 uabi_class;
-	u8 uabi_instance;
+	u16 uabi_class;
+	u16 uabi_instance;
 
 	u32 uabi_capabilities;
 	u32 context_size;
-- 
2.20.1

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^ permalink raw reply related	[flat|nested] 11+ messages in thread

end of thread, other threads:[~2020-01-19 11:15 UTC | newest]

Thread overview: 11+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-01-15 15:24 [Intel-gfx] [PATCH] drm/i915: Align engine->uabi_class/instance with i915_drm.h Tvrtko Ursulin
2020-01-15 15:28 ` Tvrtko Ursulin
2020-01-15 15:35   ` Chris Wilson
2020-01-15 16:29     ` Tvrtko Ursulin
2020-01-15 18:06 ` [Intel-gfx] ✓ Fi.CI.BAT: success for " Patchwork
2020-01-15 18:07 ` [Intel-gfx] ✗ Fi.CI.BUILD: warning " Patchwork
2020-01-16 13:45 ` [Intel-gfx] [PATCH v2] " Tvrtko Ursulin
2020-01-16 15:50 ` [Intel-gfx] ✓ Fi.CI.BAT: success for drm/i915: Align engine->uabi_class/instance with i915_drm.h (rev2) Patchwork
2020-01-16 15:50 ` [Intel-gfx] ✗ Fi.CI.BUILD: warning " Patchwork
2020-01-18  5:12 ` [Intel-gfx] ✗ Fi.CI.IGT: failure for drm/i915: Align engine->uabi_class/instance with i915_drm.h Patchwork
2020-01-19 11:15 ` [Intel-gfx] ✓ Fi.CI.IGT: success for drm/i915: Align engine->uabi_class/instance with i915_drm.h (rev2) Patchwork

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