Compiling nolibc-test.c with gcc on x86_64 got such warning: tools/testing/selftests/nolibc/nolibc-test.c: In function ‘expect_eq’: tools/testing/selftests/nolibc/nolibc-test.c:177:24: warning: format ‘%lld’ expects argument of type ‘long long int’, but argument 2 has type ‘uint64_t’ {aka ‘long unsigned int’} [-Wformat=] 177 | llen += printf(" = %lld ", expr); | ~~~^ ~~~~ | | | | | uint64_t {aka long unsigned int} | long long int | %ld It because that glibc defines uint64_t as "unsigned long int" when word size (means sizeof(long)) is 64bit (see include/bits/types.h), but nolibc directly use the 64bit "unsigned long long" (see tools/include/nolibc/stdint.h), which is simpler, seems kernel uses it too (include/uapi/asm-generic/int-ll64.h). use a simple conversion to solve it. Suggested-by: Willy Tarreau <w@xxxxxx> Link: https://lore.kernel.org/linux-riscv/20230529130449.GA2813@xxxxxx/ Signed-off-by: Zhangjin Wu <falcon@xxxxxxxxxxx> --- tools/testing/selftests/nolibc/nolibc-test.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tools/testing/selftests/nolibc/nolibc-test.c b/tools/testing/selftests/nolibc/nolibc-test.c index d417ca5d976f..403f6255c177 100644 --- a/tools/testing/selftests/nolibc/nolibc-test.c +++ b/tools/testing/selftests/nolibc/nolibc-test.c @@ -174,7 +174,7 @@ static int expect_eq(uint64_t expr, int llen, uint64_t val) { int ret = !(expr == val); - llen += printf(" = %lld ", expr); + llen += printf(" = %lld ", (long long)expr); pad_spc(llen, 64, ret ? "[FAIL]\n" : " [OK]\n"); return ret; } -- 2.25.1