While building ARCH=x86 with GCC 7.5.0 we get compilation errors:
CC drivers/gpu/drm/i915/gt/uc/intel_guc_submission.o
In file included from <command-line>:0:0:
In function ‘__guc_context_policy_add_priority.isra.47’,
inlined from ‘__guc_context_set_prio.isra.48’ at drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c:3332:3,
inlined from ‘guc_context_set_prio’ at drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c:3360:2:
././include/linux/compiler_types.h:397:38: error: call to ‘__compiletime_assert_1803’ declared with attribute error: FIELD_PREP: mask is not constant
_compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
^
././include/linux/compiler_types.h:378:4: note: in definition of macro ‘__compiletime_assert’
prefix ## suffix(); \
^~~~~~
././include/linux/compiler_types.h:397:2: note: in expansion of macro ‘_compiletime_assert’
_compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
^~~~~~~~~~~~~~~~~~~
./include/linux/build_bug.h:39:37: note: in expansion of macro ‘compiletime_assert’
#define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg)
^~~~~~~~~~~~~~~~~~
./include/linux/bitfield.h:65:3: note: in expansion of macro ‘BUILD_BUG_ON_MSG’
BUILD_BUG_ON_MSG(!__builtin_constant_p(_mask), \
^~~~~~~~~~~~~~~~
./include/linux/bitfield.h:114:3: note: in expansion of macro ‘__BF_FIELD_CHECK’
__BF_FIELD_CHECK(_mask, 0ULL, _val, "FIELD_PREP: "); \
^~~~~~~~~~~~~~~~
drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c:2461:3: note: in expansion of macro ‘FIELD_PREP’
FIELD_PREP(GUC_KLV_0_KEY, GUC_CONTEXT_POLICIES_KLV_ID_##id) | \
^~~~~~~~~~
This is due to our GUC_KLV_0_KEY definition that uses signed mask in
shift operator, which may lead to undefined behavior on 32-bit system.
Use unsigned mask to enforce expected integer promotion.
Reported-by: Linyu Yuan <quic_linyyuan@xxxxxxxxxxx>
Signed-off-by: Michal Wajdeczko <michal.wajdeczko@xxxxxxxxx>
Cc: Linyu Yuan <quic_linyyuan@xxxxxxxxxxx>
Cc: Jani Nikula <jani.nikula@xxxxxxxxx>
---
drivers/gpu/drm/i915/gt/uc/abi/guc_klvs_abi.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/i915/gt/uc/abi/guc_klvs_abi.h b/drivers/gpu/drm/i915/gt/uc/abi/guc_klvs_abi.h
index 58012edd4eb0..8e821aefb164 100644
--- a/drivers/gpu/drm/i915/gt/uc/abi/guc_klvs_abi.h
+++ b/drivers/gpu/drm/i915/gt/uc/abi/guc_klvs_abi.h
@@ -29,7 +29,7 @@
*/
#define GUC_KLV_LEN_MIN 1u
-#define GUC_KLV_0_KEY (0xffff << 16)
+#define GUC_KLV_0_KEY (0xffffu << 16)
#define GUC_KLV_0_LEN (0xffff << 0)
#define GUC_KLV_n_VALUE (0xffffffff << 0)
--
2.25.1
