drm/i915: Implement command buffer parsing logic

The command parser scans batch buffers submitted via execbuffer ioctls before
the driver submits them to hardware. At a high level, it looks for several
things:

1) Commands which are explicitly defined as privileged or which should only be
   used by the kernel driver. The parser generally rejects such commands, with
   the provision that it may allow some from the drm master process.
2) Commands which access registers. To support correct/enhanced userspace
   functionality, particularly certain OpenGL extensions, the parser provides a
   whitelist of registers which userspace may safely access (for both normal and
   drm master processes).
3) Commands which access privileged memory (i.e. GGTT, HWS page, etc). The
   parser always rejects such commands.

See the overview comment in the source for more details.

This patch only implements the logic. Subsequent patches will build the tables
that drive the parser.

v2: Don't set the secure bit if the parser succeeds
Fail harder during init
Makefile cleanup
Kerneldoc cleanup
Clarify module param description
Convert ints to bools in a few places
Move client/subclient defs to i915_reg.h
Remove the bits_count field

OTC-Tracker: AXIA-4631
Change-Id: I50b98c71c6655893291c78a2d1b8954577b37a30
Signed-off-by: Brad Volkin <bradley.d.volkin@intel.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
[danvet: Appease checkpatch.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

1 files changed, 32 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.h b/drivers/gpu/drm/i915/intel_ringbuffer.h
index 38c757e136dc..9d4c3b1182e9 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.h
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.h
@@ -164,6 +164,38 @@ struct  intel_ring_buffer {
 		u32 gtt_offset;
 		volatile u32 *cpu_page;
 	} scratch;
+
+	/*
+	 * Tables of commands the command parser needs to know about
+	 * for this ring.
+	 */
+	const struct drm_i915_cmd_table *cmd_tables;
+	int cmd_table_count;
+
+	/*
+	 * Table of registers allowed in commands that read/write registers.
+	 */
+	const u32 *reg_table;
+	int reg_count;
+
+	/*
+	 * Table of registers allowed in commands that read/write registers, but
+	 * only from the DRM master.
+	 */
+	const u32 *master_reg_table;
+	int master_reg_count;
+
+	/*
+	 * Returns the bitmask for the length field of the specified command.
+	 * Return 0 for an unrecognized/invalid command.
+	 *
+	 * If the command parser finds an entry for a command in the ring's
+	 * cmd_tables, it gets the command's length based on the table entry.
+	 * If not, it calls this function to determine the per-ring length field
+	 * encoding for the command (i.e. certain opcode ranges use certain bits
+	 * to encode the command length in the header).
+	 */
+	u32 (*get_cmd_length_mask)(u32 cmd_header);
 };
 
 static inline bool