Messages in this thread | | | Date | Sat, 9 Jul 2022 15:41:19 -0700 | Subject | Re: [PATCH tip v8] x86/setup: Use rng seeds from setup_data | From | "H. Peter Anvin" <> |
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On 7/9/22 14:57, Borislav Petkov wrote: > On Sat, Jul 09, 2022 at 02:45:24PM -0700, H. Peter Anvin wrote: >> On 7/9/22 02:49, Borislav Petkov wrote: >>> On Fri, Jul 08, 2022 at 06:51:16PM -0700, H. Peter Anvin wrote: >>>> #define SETUP_ENUM_MAX SETUP_RNG_SEED >>>> #define SETUP_INDIRECT (1<<31) >>>> #define SETUP_TYPE_MAX (SETUP_ENUM_MAX | SETUP_INDIRECT) >>> >>> Wait, if we get to add a new number, SETUP_ENUM_MAX and thus >>> SETUP_TYPE_MAX will change. And they're uapi too... >> >> Talking API here rather than ABI, i.e. the semantics of those symbols. > > Sure but do we worry about some userspace including those headers and > relying on the SETUP_ENUM_MAX number? > > Or is userspace required to be recompiled against newer uapi headers? >
In ABI/API terms, that symbol has the semantic of connecting the API version to the underlying ABI version; a piece of code that sees an enumeration type > SETUP_ENUM_MAX must by definition treat it as an opaque blob. In the future, should it become warranted, we may add flags that indicate how unaware code should handle them, but I don't think we can engineer that right now.
-hpa
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