Re: [PATCH 3/5] powerpc: tm: Always use fp_state and vr_state to store live registers
From: Simon Guo <hidden>
Date: 2016-07-17 03:25:57
Hi Cyril, On Wed, Jun 08, 2016 at 02:00:34PM +1000, Cyril Bur wrote:
quoted hunk ↗ jump to hunk
@@ -917,24 +907,10 @@ static inline void tm_recheckpoint_new_task(struct task_struct *new) "(new->msr 0x%lx, new->origmsr 0x%lx)\n", new->pid, new->thread.regs->msr, msr); - /* This loads the checkpointed FP/VEC state, if used */ tm_recheckpoint(&new->thread, msr); - /* This loads the speculative FP/VEC state, if used */ - if (msr & MSR_FP) { - do_load_up_transact_fpu(&new->thread); - new->thread.regs->msr |= - (MSR_FP | new->thread.fpexc_mode); - } -#ifdef CONFIG_ALTIVEC - if (msr & MSR_VEC) { - do_load_up_transact_altivec(&new->thread); - new->thread.regs->msr |= MSR_VEC; - } -#endif - /* We may as well turn on VSX too since all the state is restored now */ - if (msr & MSR_VSX) - new->thread.regs->msr |= MSR_VSX; + /* Won't restore math get called later? */ + restore_math(new->thread.regs);
I have some question for the "restore_math" in tm_recheckpoint_new_task(). Per my understanding, now after tm_recheckpoint, the fp_state content is obsolete. However restore_math() will try to restore FP/Vec/VSX state from fp_state, (orginally it is right, since fp_state was the valid checkpointed state and consistent with FP register ). Should we remove the restore_math() here? And, should the thread's MSR now set FP bit in tm_recheckpoint(), to indicate that FP register content is "fresh" in contrast to thread.fp_state? Please correct me if I am wrong. Thanks, - Simon