When building the kernel with Clang with defconfig and CONFIG_64BIT disabled, vmlinux fails to link because of the BUILD_BUG in _print_param. ld: drivers/gpu/drm/i915/i915_params.o: in function `i915_params_dump': i915_params.c:(.text+0x56): undefined reference to `__compiletime_assert_191' This function is semantically invalid unless the code is first inlined then constant folded, which doesn't work for Clang because semantic analysis happens before optimization/inlining. [The above written by Nathan Chancellor <natechancellor@xxxxxxxxx>] Use WARN_ONCE() instead of BUILD_BUG() to avoid the problem. The WARN_ONCE() should get optimized away unless there's a type that's not handled by _print_param(). References: https://github.com/ClangBuiltLinux/linux/issues/191 References: http://mid.mail-archive.com/20181009171401.14980-1-natechancellor@xxxxxxxxx Cc: Nick Desaulniers <ndesaulniers@xxxxxxxxxx> Cc: Nathan Chancellor <natechancellor@xxxxxxxxx> Cc: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> Reported-by: Nick Desaulniers <ndesaulniers@xxxxxxxxxx> Reported-by: Nathan Chancellor <natechancellor@xxxxxxxxx> Signed-off-by: Jani Nikula <jani.nikula@xxxxxxxxx> --- drivers/gpu/drm/i915/i915_params.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/i915/i915_params.c b/drivers/gpu/drm/i915/i915_params.c index bd6bd8879cab..8d71886b5f03 100644 --- a/drivers/gpu/drm/i915/i915_params.c +++ b/drivers/gpu/drm/i915/i915_params.c @@ -184,7 +184,8 @@ static __always_inline void _print_param(struct drm_printer *p, else if (!__builtin_strcmp(type, "char *")) drm_printf(p, "i915.%s=%s\n", name, *(const char **)x); else - BUILD_BUG(); + WARN_ONCE(1, "no printer defined for param type %s (i915.%s)\n", + type, name); } /** -- 2.11.0 _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
