On Fri, Aug 12, 2016 at 09:28:17AM +1000, Cyril Bur wrote:
> @@ -846,7 +834,9 @@ static void tm_reclaim_thread(struct thread_struct *thr,
> if (!MSR_TM_SUSPENDED(mfmsr()))
> return;
>
> - tm_reclaim(thr, thr->regs->msr, cause);
> + giveup_all(container_of(thr, struct task_struct, thread));
> +
> + tm_reclaim(thr, msr_diff, cause);
>
> /* Having done the reclaim, we now have the checkpointed
> * FP/VSX values in the registers. These might be valid
> @@ -1189,11 +1171,11 @@ struct task_struct *__switch_to(struct task_struct
> *prev,
> */
> save_sprs(&prev->thread);
>
> - __switch_to_tm(prev);
> -
> /* Save FPU, Altivec, VSX and SPE state */
> giveup_all(prev);
>
> + __switch_to_tm(prev, new);
> +
> /*
> * We can't take a PMU exception inside _switch() since there is a
> * window where the kernel stack SLB and the kernel stack are out
There are 2 "giveall_all()" in above path:
__switch_to()
giveup_all() // first time
__switch_to_tm()
tm_reclaim_task()
tm_reclaim_thread()
giveup_all() // again????
We should remove the one in __switch_to().
And another question, for following code in tm_reclaim_thread():
/* Having done the reclaim, we now have the checkpointed
* FP/VSX values in the registers. These might be valid
* even if we have previously called enable_kernel_fp() or
* flush_fp_to_thread(), so update thr->regs->msr to
* indicate their current validity.
*/
thr->regs->msr |= msr_diff;
Does it imply the task being switched out of CPU, with TIF_RESTORE_TM
bit set, might end with MSR_FP enabled? (I thought MSR_FP should not
be enabled for a switched out task, as specified in
flush_fp_to_thread())
Thanks,
- Simon
