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Fri, 24 Jul 2020 11:25:23 +1000 (AEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=neuling.org; s=201811; t=1595553924; bh=tm/GU39NPJjOhnUmHyDDcZvMhBdG0uDx7EnJQcKGEho=; h=Subject:From:To:Date:In-Reply-To:References:From; b=XOKW50YAnge0+7ZmdCpLdxd8P+Gx1IVElGxDtqg7n8o2DtROhV6Gd/km0jYnjiC5d /guTMY0h5sHwhoVmVXsZFdgGiGM9zm11xlDj4acp0AgSgtthMRCkNppZKXVVdG4iMg JERKTsxs0ZF3wBBn9wjRNUEyGlmhJhF0hZCj6qrOhp1HbGf0lwrJ5PKG9bEDe0sM53 J8o/9EnQDDNAxlM/rMc/M5KUEUi26pwhuMQgxnB2wu4egOTE0sBUQ9/Ml1Zt01Ve3w pUVyVFS4/UiiX4lK6r5AKsCnqErfhyLdIIW+MCNbRLYdgaQO1KyqcYNBh6aAUWkz1f 3o3gS8l4YgcjA== Received: by neuling.org (Postfix, from userid 1000) id 3D9482C0404; Fri, 24 Jul 2020 11:25:23 +1000 (AEST) Message-ID: Subject: Re: [PATCH v2 2/3] powerpc/powernv/idle: save-restore DAWR0,DAWRX0 for P10 From: Michael Neuling To: Pratik Rajesh Sampat , mpe@ellerman.id.au, benh@kernel.crashing.org, paulus@samba.org, ravi.bangoria@linux.ibm.com, ego@linux.vnet.ibm.com, svaidy@linux.ibm.com, pratik.r.sampat@gmail.com, linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org Date: Fri, 24 Jul 2020 11:25:23 +1000 In-Reply-To: <20200710052207.12003-3-psampat@linux.ibm.com> References: <20200710052207.12003-1-psampat@linux.ibm.com> <20200710052207.12003-3-psampat@linux.ibm.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.36.4 (3.36.4-1.fc32) MIME-Version: 1.0 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Fri, 2020-07-10 at 10:52 +0530, Pratik Rajesh Sampat wrote: > Additional registers DAWR0, DAWRX0 may be lost on Power 10 for > stop levels < 4. > Therefore save the values of these SPRs before entering a "stop" > state and restore their values on wakeup. >=20 > Signed-off-by: Pratik Rajesh Sampat > --- > arch/powerpc/platforms/powernv/idle.c | 10 ++++++++++ > 1 file changed, 10 insertions(+) >=20 > diff --git a/arch/powerpc/platforms/powernv/idle.c > b/arch/powerpc/platforms/powernv/idle.c > index 19d94d021357..f2e2a6a4c274 100644 > --- a/arch/powerpc/platforms/powernv/idle.c > +++ b/arch/powerpc/platforms/powernv/idle.c > @@ -600,6 +600,8 @@ struct p9_sprs { > u64 iamr; > u64 amor; > u64 uamor; > + u64 dawr0; > + u64 dawrx0; > }; > =20 > static unsigned long power9_idle_stop(unsigned long psscr, bool mmu_on) > @@ -687,6 +689,10 @@ static unsigned long power9_idle_stop(unsigned long > psscr, bool mmu_on) > sprs.iamr =3D mfspr(SPRN_IAMR); > sprs.amor =3D mfspr(SPRN_AMOR); > sprs.uamor =3D mfspr(SPRN_UAMOR); > + if (cpu_has_feature(CPU_FTR_ARCH_31)) { Can you add a comment here saying even though DAWR0 is ARCH_30, it's only required to be saved on 31. Otherwise this looks pretty odd. > + sprs.dawr0 =3D mfspr(SPRN_DAWR0); > + sprs.dawrx0 =3D mfspr(SPRN_DAWRX0); > + } > =20 > srr1 =3D isa300_idle_stop_mayloss(psscr); /* go idle */ > =20 > @@ -710,6 +716,10 @@ static unsigned long power9_idle_stop(unsigned long > psscr, bool mmu_on) > mtspr(SPRN_IAMR, sprs.iamr); > mtspr(SPRN_AMOR, sprs.amor); > mtspr(SPRN_UAMOR, sprs.uamor); > + if (cpu_has_feature(CPU_FTR_ARCH_31)) { > + mtspr(SPRN_DAWR0, sprs.dawr0); > + mtspr(SPRN_DAWRX0, sprs.dawrx0); > + } > =20 > /* > * Workaround for POWER9 DD2.0, if we lost resources, the ERAT