On Fri, Jul 13, 2018 at 03:54:29PM +0200, Ard Biesheuvel wrote: > Did you have any thoughts about how we could at least detect > situations where we are invoking protocols that are not mixed-mode > safe (i.e., they pass 64-bit quantities by value, which our current > thunking routine does not take into account) efi_thunk_64.S only supports five arguments AFAICS, we'd have to check for each argument passed to efi_call_early() or efi_call_proto() if the corresponding argument in the *_32_t protocol struct has sizeof(u64), and BUILD_BUG_ON() if so. Is it possible to retrieve the n-th element of a struct without knowing its name? Basically offsetof() but with a number instead of a name? We have to check the size of the struct element, not the argument passed in to efi_call_early() / efi_call_proto() because we pass in 64-bit pointers (and possibly also integers) and fully expect that the upper 32-bit are disregarded. Difficult. :-( Lukas -- To unsubscribe from this list: send the line "unsubscribe linux-efi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
