On Tue, Nov 19, 2024 at 04:34:53PM +0100, Valentin Schneider wrote: > Later commits will cause objtool to warn about non __ro_after_init static > keys being used in .noinstr sections in order to safely defer instruction > patching IPIs targeted at NOHZ_FULL CPUs. Don't we need similar checking for static calls? > Two such keys currently exist: mds_idle_clear and __sched_clock_stable, > which can both be modified at runtime. Not sure if feasible, but it sure would be a lot simpler to just make "no noinstr patching" a hard rule and then convert the above keys (or at least their noinstr-specific usage) to regular branches. Then "no noinstr patching" could be unilaterally enforced in text_poke_bp(). > diff --git a/include/linux/jump_label.h b/include/linux/jump_label.h > index f5a2727ca4a9a..93e729545b941 100644 > --- a/include/linux/jump_label.h > +++ b/include/linux/jump_label.h > @@ -200,7 +200,8 @@ struct module; > #define JUMP_TYPE_FALSE 0UL > #define JUMP_TYPE_TRUE 1UL > #define JUMP_TYPE_LINKED 2UL > -#define JUMP_TYPE_MASK 3UL > +#define JUMP_TYPE_FORCEFUL 4UL JUMP_TYPE_NOINSTR_ALLOWED ? -- Josh
