Re: [PATCH v3 2/3] powerpc/powernv/idle: Rename pnv_first_spr_loss_level variable

[Pratik Sampat]

On 20/07/20 5:27 am, Nicholas Piggin wrote:
> Excerpts from Pratik Rajesh Sampat's message of July 18, 2020 4:53 am:
> > Replace the variable name from using "pnv_first_spr_loss_level" to
> > "pnv_first_fullstate_loss_level".
> >
> > As pnv_first_spr_loss_level is supposed to be the earliest state that
> > has OPAL_PM_LOSE_FULL_CONTEXT set, however as shallow states too loose
> > SPR values, render an incorrect terminology.
> It also doesn't lose "full" state at this loss level though. From the
> architecture it could be called "hv state loss level", but in POWER10
> even that is not strictly true.
Right. Just discovered that deep stop states won't loose full state
P10 onwards.
Would it better if we rename it as "pnv_all_spr_loss_state" instead
so that it stays generic enough while being semantically coherent?

Thanks
Pratik

> > Signed-off-by: Pratik Rajesh Sampat <psampat@xxxxxxxxxxxxx>
> > ---
> >   arch/powerpc/platforms/powernv/idle.c | 18 +++++++++---------
> >   1 file changed, 9 insertions(+), 9 deletions(-)
> >
> > diff --git a/arch/powerpc/platforms/powernv/idle.c b/arch/powerpc/platforms/powernv/idle.c
> > index f62904f70fc6..d439e11af101 100644
> > --- a/arch/powerpc/platforms/powernv/idle.c
> > +++ b/arch/powerpc/platforms/powernv/idle.c
> > @@ -48,7 +48,7 @@ static bool default_stop_found;
> >    * First stop state levels when SPR and TB loss can occur.
> >    */
> >   static u64 pnv_first_tb_loss_level = MAX_STOP_STATE + 1;
> > -static u64 pnv_first_spr_loss_level = MAX_STOP_STATE + 1;
> > +static u64 pnv_first_fullstate_loss_level = MAX_STOP_STATE + 1;
> >   
> >   /*
> >    * psscr value and mask of the deepest stop idle state.
> > @@ -657,7 +657,7 @@ static unsigned long power9_idle_stop(unsigned long psscr, bool mmu_on)
> >   		  */
> >   		mmcr0		= mfspr(SPRN_MMCR0);
> >   	}
> > -	if ((psscr & PSSCR_RL_MASK) >= pnv_first_spr_loss_level) {
> > +	if ((psscr & PSSCR_RL_MASK) >= pnv_first_fullstate_loss_level) {
> >   		sprs.lpcr	= mfspr(SPRN_LPCR);
> >   		sprs.hfscr	= mfspr(SPRN_HFSCR);
> >   		sprs.fscr	= mfspr(SPRN_FSCR);
> > @@ -741,7 +741,7 @@ static unsigned long power9_idle_stop(unsigned long psscr, bool mmu_on)
> >   	 * just always test PSSCR for SPR/TB state loss.
> >   	 */
> >   	pls = (psscr & PSSCR_PLS) >> PSSCR_PLS_SHIFT;
> > -	if (likely(pls < pnv_first_spr_loss_level)) {
> > +	if (likely(pls < pnv_first_fullstate_loss_level)) {
> >   		if (sprs_saved)
> >   			atomic_stop_thread_idle();
> >   		goto out;
> > @@ -1088,7 +1088,7 @@ static void __init pnv_power9_idle_init(void)
> >   	 * the deepest loss-less (OPAL_PM_STOP_INST_FAST) stop state.
> >   	 */
> >   	pnv_first_tb_loss_level = MAX_STOP_STATE + 1;
> > -	pnv_first_spr_loss_level = MAX_STOP_STATE + 1;
> > +	pnv_first_fullstate_loss_level = MAX_STOP_STATE + 1;
> >   	for (i = 0; i < nr_pnv_idle_states; i++) {
> >   		int err;
> >   		struct pnv_idle_states_t *state = &pnv_idle_states[i];
> > @@ -1099,8 +1099,8 @@ static void __init pnv_power9_idle_init(void)
> >   			pnv_first_tb_loss_level = psscr_rl;
> >   
> >   		if ((state->flags & OPAL_PM_LOSE_FULL_CONTEXT) &&
> > -		     (pnv_first_spr_loss_level > psscr_rl))
> > -			pnv_first_spr_loss_level = psscr_rl;
> > +		     (pnv_first_fullstate_loss_level > psscr_rl))
> > +			pnv_first_fullstate_loss_level = psscr_rl;
> >   
> >   		/*
> >   		 * The idle code does not deal with TB loss occurring
> > @@ -1111,8 +1111,8 @@ static void __init pnv_power9_idle_init(void)
> >   		 * compatibility.
> >   		 */
> >   		if ((state->flags & OPAL_PM_TIMEBASE_STOP) &&
> > -		     (pnv_first_spr_loss_level > psscr_rl))
> > -			pnv_first_spr_loss_level = psscr_rl;
> > +		     (pnv_first_fullstate_loss_level > psscr_rl))
> > +			pnv_first_fullstate_loss_level = psscr_rl;
> >   
> >   		err = validate_psscr_val_mask(&state->psscr_val,
> >   					      &state->psscr_mask,
> > @@ -1158,7 +1158,7 @@ static void __init pnv_power9_idle_init(void)
> >   	}
> >   
> >   	pr_info("cpuidle-powernv: First stop level that may lose SPRs = 0x%llx\n",
> > -		pnv_first_spr_loss_level);
> > +		pnv_first_fullstate_loss_level);
> >   
> >   	pr_info("cpuidle-powernv: First stop level that may lose timebase = 0x%llx\n",
> >   		pnv_first_tb_loss_level);
> > --
> > 2.25.4