In order to prevent the following complaint from happening, always inline the u128 variant of mul_u64_u64_shr() -- which is what x86_64 will use. vmlinux.o: warning: objtool: read_hv_sched_clock_tsc+0x5a: call to mul_u64_u64_shr.constprop.0() leaves .noinstr.text section It should compile into something like: asm("mul %[mul];" "shrd %rdx, %rax, %cl" : "+&a" (a) : "c" shift, [mul] "r" (mul) : "d"); Which is silly not to inline, but it happens. Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx> --- include/linux/math64.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/include/linux/math64.h +++ b/include/linux/math64.h @@ -168,7 +168,7 @@ static __always_inline u64 mul_u64_u32_s #endif /* mul_u64_u32_shr */ #ifndef mul_u64_u64_shr -static inline u64 mul_u64_u64_shr(u64 a, u64 mul, unsigned int shift) +static __always_inline u64 mul_u64_u64_shr(u64 a, u64 mul, unsigned int shift) { return (u64)(((unsigned __int128)a * mul) >> shift); }