2022-07-17 02:47:06

by Yonghong Song

[permalink] [raw]
Subject: Re: [PATCH bpf-next 5/5] selftests/bpf: Remove the casting about jited_ksyms and jited_linfo



On 7/16/22 5:51 AM, Pu Lehui wrote:
> We have unified data extension operation of jited_ksyms and jited_linfo
> into zero extension, so there's no need to cast u64 memory address to
> long data type.

For subject, we are not 'Remove the casting ...'. What the code did is
to change the casting.

Also, I don't understand the above commit message. What does this mean
about 'data extension operation of jited_ksyms and jited_linfo into zero
extension'?

In prog_tests/btf.c, we have a few other places to cast
jited_linfo[...]/jited_ksyms[...] to 'long' type. Maybe casting
to 'unsigned long' is a better choice. Casting to 'unsigned long long'
of course will work, but is it necessary? Or you are talking about
64bit kernel and 32bit user space?

>
> Signed-off-by: Pu Lehui <[email protected]>
> ---
> tools/testing/selftests/bpf/prog_tests/btf.c | 16 +++++++++-------
> 1 file changed, 9 insertions(+), 7 deletions(-)
>
> diff --git a/tools/testing/selftests/bpf/prog_tests/btf.c b/tools/testing/selftests/bpf/prog_tests/btf.c
> index e852a9df779d..db10fa1745d1 100644
> --- a/tools/testing/selftests/bpf/prog_tests/btf.c
> +++ b/tools/testing/selftests/bpf/prog_tests/btf.c
> @@ -6613,8 +6613,9 @@ static int test_get_linfo(const struct prog_info_raw_test *test,
> }
>
> if (CHECK(jited_linfo[0] != jited_ksyms[0],
> - "jited_linfo[0]:%lx != jited_ksyms[0]:%lx",
> - (long)(jited_linfo[0]), (long)(jited_ksyms[0]))) {
> + "jited_linfo[0]:%llx != jited_ksyms[0]:%llx",
> + (unsigned long long)(jited_linfo[0]),
> + (unsigned long long)(jited_ksyms[0]))) {
> err = -1;
> goto done;
> }
> @@ -6632,16 +6633,17 @@ static int test_get_linfo(const struct prog_info_raw_test *test,
> }
>
> if (CHECK(jited_linfo[i] <= jited_linfo[i - 1],
> - "jited_linfo[%u]:%lx <= jited_linfo[%u]:%lx",
> - i, (long)jited_linfo[i],
> - i - 1, (long)(jited_linfo[i - 1]))) {
> + "jited_linfo[%u]:%llx <= jited_linfo[%u]:%llx",
> + i, (unsigned long long)jited_linfo[i],
> + i - 1, (unsigned long long)(jited_linfo[i - 1]))) {
> err = -1;
> goto done;
> }
>
> if (CHECK(jited_linfo[i] - cur_func_ksyms > cur_func_len,
> - "jited_linfo[%u]:%lx - %lx > %u",
> - i, (long)jited_linfo[i], (long)cur_func_ksyms,
> + "jited_linfo[%u]:%llx - %llx > %u",
> + i, (unsigned long long)jited_linfo[i],
> + (unsigned long long)cur_func_ksyms,
> cur_func_len)) {
> err = -1;
> goto done;