On 03/22/17 13:44, Andy Lutomirski wrote:
>
> While it's possible that silently papering over the bug is slightly
> faster than BUGging, it will allow bugs to continue to exist
> undetected.
>
It would also allow the test to be inlined (at least on architectures
which have a one-site implementation) and have only the failure case out
of line, with a __noreturn annotation (which allows it to be jumped to
rather than called, which is usually available as a conditional
operation whereas call often isn't.)
That is...
extern void __noreturn __pre_usermode_state_invalid(void);
static void verify_pre_usermode_state(void)
{
if (unlikely(!segment_eq(get_fs(), USER_DS))
__pre_usermode_state_invalid();
}
-hpa
