From 1b9fc94a7751259398e006c2c2f3c7fb28e5ff7a Mon Sep 17 00:00:00 2001 From: Michal Wajdeczko Date: Fri, 17 Jan 2020 08:20:35 +0000 Subject: [PATCH] drm/i915/guc: Don't GEM_BUG_ON on corrupted G2H CTB We should never BUG_ON on any corruption in CTB descriptor as data there can be also modified by the GuC. Instead we can use flag "is_in_error" to indicate that we will not process any further messages over this CTB (until reset). While here move descriptor error reporting to the function that actually touches that descriptor. Note that unexpected content of the specific CT messages, that still complies with generic CT message format, shall not trigger disabling whole CTB, as that might just indicate new unsupported message types. v2: drop redundant message (Daniele) Signed-off-by: Michal Wajdeczko Cc: Chris Wilson Cc: Daniele Ceraolo Spurio Reviewed-by: Daniele Ceraolo Spurio Signed-off-by: Chris Wilson Link: https://patchwork.freedesktop.org/patch/msgid/20200117082039.65644-2-michal.wajdeczko@intel.com --- drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c | 38 ++++++++++++++++++------------- 1 file changed, 22 insertions(+), 16 deletions(-) diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c b/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c index a55c336..46e4faf 100644 --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c @@ -578,19 +578,25 @@ static inline bool ct_header_is_response(u32 header) static int ctb_read(struct intel_guc_ct_buffer *ctb, u32 *data) { struct guc_ct_buffer_desc *desc = ctb->desc; - u32 head = desc->head / 4; /* in dwords */ - u32 tail = desc->tail / 4; /* in dwords */ - u32 size = desc->size / 4; /* in dwords */ + u32 head = desc->head; + u32 tail = desc->tail; + u32 size = desc->size; u32 *cmds = ctb->cmds; - s32 available; /* in dwords */ + s32 available; unsigned int len; unsigned int i; - GEM_BUG_ON(desc->size % 4); - GEM_BUG_ON(desc->head % 4); - GEM_BUG_ON(desc->tail % 4); - GEM_BUG_ON(tail >= size); - GEM_BUG_ON(head >= size); + if (unlikely(desc->is_in_error)) + return -EPIPE; + + if (unlikely(!IS_ALIGNED(head | tail | size, 4) || + (tail | head) >= size)) + goto corrupted; + + /* later calculations will be done in dwords */ + head /= 4; + tail /= 4; + size /= 4; /* tail == head condition indicates empty */ available = tail - head; @@ -615,7 +621,7 @@ static int ctb_read(struct intel_guc_ct_buffer *ctb, u32 *data) size - head : available - 1), &cmds[head], 4 * (head + available - 1 > size ? available - 1 - size + head : 0), &cmds[0]); - return -EPROTO; + goto corrupted; } for (i = 1; i < len; i++) { @@ -626,6 +632,12 @@ static int ctb_read(struct intel_guc_ct_buffer *ctb, u32 *data) desc->head = head * 4; return 0; + +corrupted: + DRM_ERROR("CT: Corrupted descriptor addr=%#x head=%u tail=%u size=%u\n", + desc->addr, desc->head, desc->tail, desc->size); + desc->is_in_error = 1; + return -EPIPE; } /** @@ -836,10 +848,4 @@ void intel_guc_ct_event_handler(struct intel_guc_ct *ct) else err = ct_handle_request(ct, msg); } while (!err); - - if (GEM_WARN_ON(err == -EPROTO)) { - CT_ERROR(ct, "Corrupted message: %#x\n", msg[0]); - ctb->desc->is_in_error = 1; - } } - -- 2.7.4