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charset="utf-8" Go a step further than bed9ae54df44 ("x86/time: switch platform timer hooks to altcall") did and eliminate the "real" read_tsc() altogether: It's not used except in pointer comparisons, and hence it looks overall more safe to simply poison plt_tsc's read_counter hook. Signed-off-by: Jan Beulich --- I wasn't really sure whether it would be better to use simply void * for the type of the expression, resulting in an undesirable data -> function pointer conversion, but making it impossible to mistakenly try and call the (fake) function directly. --- a/xen/arch/x86/time.c +++ b/xen/arch/x86/time.c @@ -585,10 +585,12 @@ static s64 __init cf_check init_tsc(stru return ret; } =20 -static uint64_t __init cf_check read_tsc(void) -{ - return rdtsc_ordered(); -} +/* + * plt_tsc's read_counter hook is (and should not be) invoked via the stru= ct + * field. To avoid carrying an unused, indirectly reachable function, pois= on + * the field with an easily identifiable non-canonical pointer. + */ +#define read_tsc ((uint64_t(*)(void))0x75C75C75C75C75C0ul) =20 static struct platform_timesource __initdata plt_tsc =3D {