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From: Michael Neuling <mikey@neuling.org>
To: "Gautham R. Shenoy" <ego@linux.vnet.ibm.com>,
	Michael Ellerman <mpe@ellerman.id.au>,
	Benjamin Herrenschmidt <benh@kernel.crashing.org>,
	Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>
Cc: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org,
	Florian Weimer <fweimer@redhat.com>,
	Oleg Nesterov <oleg@redhat.com>
Subject: Re: [RESEND][PATCH] powerpc/powernv : Save/Restore SPRG3 on entry/exit from stop.
Date: Wed, 18 Jul 2018 09:24:19 +1000	[thread overview]
Message-ID: <80bbdf47081e3e302ab5f28b5ddc9e2faabba842.camel@neuling.org> (raw)
In-Reply-To: <1531843216-22209-1-git-send-email-ego@linux.vnet.ibm.com>


>  	DEFINE(PPC_DBELL_SERVER, PPC_DBELL_SERVER);
> diff --git a/arch/powerpc/kernel/idle_book3s.S
> b/arch/powerpc/kernel/idle_book3s.S
> index d85d551..5069d42 100644
> --- a/arch/powerpc/kernel/idle_book3s.S
> +++ b/arch/powerpc/kernel/idle_book3s.S
> @@ -120,6 +120,9 @@ power9_save_additional_sprs:
>  	mfspr	r4, SPRN_MMCR2
>  	std	r3, STOP_MMCR1(r13)
>  	std	r4, STOP_MMCR2(r13)
> +
> +	mfspr	r3, SPRN_SPRG3
> +	std	r3, STOP_SPRG3(r13)

We don't need to save it.  Just restore it from paca->sprg_vdso which should
never change.

How can we do better at catching these missing SPRGs? 

We missed this one and looking at c1b25a17d249 we missed the AMOR a couple of
months back. I'd rather we had some systematic way of finding the ones we are
missing, rather than playing wake-a-mole.

Mikey 

>  	blr
>  
>  power9_restore_additional_sprs:
> @@ -144,7 +147,9 @@ power9_restore_additional_sprs:
>  	mtspr	SPRN_MMCR1, r4
>  
>  	ld	r3, STOP_MMCR2(r13)
> +	ld	r4, STOP_SPRG3(r13)
>  	mtspr	SPRN_MMCR2, r3
> +	mtspr	SPRN_SPRG3, r4
>  	blr
>  
>  /*

WARNING: multiple messages have this Message-ID (diff)
From: Michael Neuling <mikey@neuling.org>
To: "Gautham R. Shenoy" <ego@linux.vnet.ibm.com>,
	Michael Ellerman <mpe@ellerman.id.au>,
	Benjamin Herrenschmidt <benh@kernel.crashing.org>,
	Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>
Cc: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org,
	Florian Weimer <fweimer@redhat.com>,
	Oleg Nesterov <oleg@redhat.com>
Subject: Re: [RESEND][PATCH] powerpc/powernv : Save/Restore SPRG3 on entry/exit from stop.
Date: Wed, 18 Jul 2018 09:24:19 +1000	[thread overview]
Message-ID: <80bbdf47081e3e302ab5f28b5ddc9e2faabba842.camel@neuling.org> (raw)
In-Reply-To: <1531843216-22209-1-git-send-email-ego@linux.vnet.ibm.com>


>  	DEFINE(PPC_DBELL_SERVER, PPC_DBELL_SERVER);
> diff --git a/arch/powerpc/kernel/idle_book3s.S
> b/arch/powerpc/kernel/idle_book3s.S
> index d85d551..5069d42 100644
> --- a/arch/powerpc/kernel/idle_book3s.S
> +++ b/arch/powerpc/kernel/idle_book3s.S
> @@ -120,6 +120,9 @@ power9_save_additional_sprs:
>  	mfspr	r4, SPRN_MMCR2
>  	std	r3, STOP_MMCR1(r13)
>  	std	r4, STOP_MMCR2(r13)
> +
> +	mfspr	r3, SPRN_SPRG3
> +	std	r3, STOP_SPRG3(r13)

We don't need to save it.  Just restore it from paca->sprg_vdso which shoul=
d
never change.

How can we do better at catching these missing SPRGs?=20

We missed this one and looking at c1b25a17d249 we missed the AMOR a couple =
of
months back. I'd rather we had some systematic way of finding the ones we a=
re
missing, rather than playing wake-a-mole.

Mikey=20

>  	blr
> =20
>  power9_restore_additional_sprs:
> @@ -144,7 +147,9 @@ power9_restore_additional_sprs:
>  	mtspr	SPRN_MMCR1, r4
> =20
>  	ld	r3, STOP_MMCR2(r13)
> +	ld	r4, STOP_SPRG3(r13)
>  	mtspr	SPRN_MMCR2, r3
> +	mtspr	SPRN_SPRG3, r4
>  	blr
> =20
>  /*

  reply	other threads:[~2018-07-17 23:24 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-07-17 11:27 [PATCH] powerpc/powernv : Save/Restore SPRG3 on entry/exit from stop Gautham R. Shenoy
2018-07-17 11:47 ` Gautham R Shenoy
2018-07-17 16:00 ` [RESEND][PATCH] " Gautham R. Shenoy
2018-07-17 23:24   ` Michael Neuling [this message]
2018-07-17 23:24     ` Michael Neuling
2018-07-18  8:12     ` Gautham R Shenoy
2018-07-20  0:27       ` Michael Neuling
2018-07-20  0:27         ` Michael Neuling
2018-07-20  2:32         ` Michael Ellerman
2018-07-20  2:41           ` Michael Neuling
2018-07-20  2:41             ` Michael Neuling
2018-07-20  6:29             ` Michael Ellerman
2018-07-20  6:29               ` Michael Ellerman
2018-07-20  7:05               ` Michael Neuling
2018-07-20  7:05                 ` Michael Neuling

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