On March 17, 2025 6:51:50 PM PDT, Tzung-Bi Shih <tzungbi@xxxxxxxxxx> wrote:
>On Mon, Mar 17, 2025 at 12:04:47PM +0000, Jonathan Cameron wrote:
>> On Mon, 17 Mar 2025 15:10:38 +1030
>> "Gustavo A. R. Silva" <gustavo@xxxxxxxxxxxxxx> wrote:
>>
>> > On 17/03/25 12:02, Tzung-Bi Shih wrote:
>> > > On Mon, Mar 17, 2025 at 11:24:59AM +1030, Gustavo A. R. Silva wrote:
>> > >> static int cros_ec_get_host_cmd_version_mask(struct cros_ec_device *ec_dev,
>> > >> u16 cmd_offset, u16 cmd, u32 *mask)
>> > >> {
>> > >> + DEFINE_RAW_FLEX(struct cros_ec_command, buf, data,
>> > >> + sizeof(struct ec_response_get_cmd_versions));
>> > >
>> > > max(sizeof(struct ec_params_get_cmd_versions),
>> > > sizeof(struct ec_response_get_cmd_versions))?
>> >
>> > I considered that, but DEFINE_RAW_FLEX() complains about it due to the
>> >
>> > _Static_assert(__builtin_constant_p(count), \
>> > "onstack flex array members require compile-time const count");
>> >
>> Maybe add an assert that you indeed have the larger of the two + a comment
>> on why it matters?
>
>Or, is there a way for using compiler-time MAX()? I failed to find so.
Did MAX() not work? I would expect it to do compile time comparison of two sizeof()s. It can do other arithmetic no problem, e.g.:
https://elixir.bootlin.com/linux/v6.13.7/source/lib/vsprintf.c#L1097
--
Kees Cook
