From 7b3e51dd439bead71d9e4504d89a32a8496ac0aa Mon Sep 17 00:00:00 2001 From: Jani Nikula Date: Tue, 16 Oct 2018 15:29:37 +0300 Subject: [PATCH] drm/i915: Ensure _print_param() builds with Clang 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 ] 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@gmail.com Cc: Nick Desaulniers Cc: Nathan Chancellor Cc: Chris Wilson Reported-by: Nick Desaulniers Reported-by: Nathan Chancellor Tested-by: Nathan Chancellor Reviewed-by: Chris Wilson Reviewed-by: Nick Desaulniers Signed-off-by: Jani Nikula Link: https://patchwork.freedesktop.org/patch/msgid/20181016122938.18757-1-jani.nikula@intel.com --- 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); } /** -- 2.20.1