From: Changbin Du <changbin.du@xxxxxxxxx> With '-Og' optimization level, GCC would not optimize a count for a loop as a constant value. But BUILD_BUG_ON() only accept compile-time constant values. arch/arm/mm/mmu.o: In function `fix_to_virt': /home/changbin/work/linux/./include/asm-generic/fixmap.h:31: undefined reference to `__compiletime_assert_31' Makefile:1051: recipe for target 'vmlinux' failed make: *** [vmlinux] Error 1 Signed-off-by: Changbin Du <changbin.du@xxxxxxxxx> --- include/asm-generic/fixmap.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/include/asm-generic/fixmap.h b/include/asm-generic/fixmap.h index 827e4d3..a6576d4 100644 --- a/include/asm-generic/fixmap.h +++ b/include/asm-generic/fixmap.h @@ -28,7 +28,8 @@ */ static __always_inline unsigned long fix_to_virt(const unsigned int idx) { - BUILD_BUG_ON(idx >= __end_of_fixed_addresses); + BUILD_BUG_ON(__builtin_constant_p(idx) && + idx >= __end_of_fixed_addresses); return __fix_to_virt(idx); } -- 2.7.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kbuild" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html