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. Let's use __fix_to_virt() to avoid the error. 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> Acked-by: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx> --- arch/arm/mm/mmu.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c index e46a6a446cdd..c08d74e76714 100644 --- a/arch/arm/mm/mmu.c +++ b/arch/arm/mm/mmu.c @@ -1599,7 +1599,7 @@ static void __init early_fixmap_shutdown(void) pte_t *pte; struct map_desc map; - map.virtual = fix_to_virt(i); + map.virtual = __fix_to_virt(i); pte = pte_offset_early_fixmap(pmd_off_k(map.virtual), map.virtual); /* Only i/o device mappings are supported ATM */ -- 2.17.1
