Re: [PATCH v6 07/12] x86/cpu/keylocker: Load an internal wrapping key at boot-time

Dave Hansen
2023-05-08T21:56:53Z

On 5/8/23 11:18, Chang S. Bae wrote:
> On 5/5/2023 4:05 PM, Eric Biggers wrote:
>> On Mon, Apr 10, 2023 at 03:59:31PM -0700, Chang S. Bae wrote:
>>>   +#ifdef CONFIG_X86_KEYLOCKER
>>> +void setup_keylocker(struct cpuinfo_x86 *c);
>>> +void destroy_keylocker_data(void);
>>> +#else
>>> +#define setup_keylocker(c) do { } while (0)
>>> +#define destroy_keylocker_data() do { } while (0)
>>> +#endif
>>
>> Shouldn't the !CONFIG_X86_KEYLOCKER stubs be static inline functions
>> instead of
>> macros, so that type checking works?
>
> I think either way works here. This macro is just for nothing.

Chang, I do prefer the 'static inline' as a general rule. Think of this:

static inline void setup_keylocker(struct cpuinfo_x86 *c) {}

versus:

#define setup_keylocker(c) do { } while (0)

Imagine some dope does:

char c;
...
setup_keylocker(c);

With the macro, they'll get no type warning. The inline actually makes
it easier to find bugs because folks will get _some_ type checking no
matter how they compile the code.