From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ozlabs.org (ozlabs.org [103.22.144.67]) (using TLSv1.2 with cipher ADH-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 3wYL7C56w9zDqBJ for ; Thu, 25 May 2017 17:12:23 +1000 (AEST) Message-ID: <1495696343.7239.4.camel@neuling.org> Subject: Re: [PATCH] powerpc: Fix booting P9 hash with CONFIG_PPC_RADIX_MMU=N From: Michael Neuling To: "Aneesh Kumar K.V" , mpe@ellerman.id.au, linuxppc-dev@lists.ozlabs.org, anton@samba.org, Greg Johnson Date: Thu, 25 May 2017 17:12:23 +1000 In-Reply-To: <8737btr6jb.fsf@skywalker.in.ibm.com> References: <20170524070326.13531-1-mikey@neuling.org> <87bmqir5tl.fsf@skywalker.in.ibm.com> <1495671229.18002.1.camel@neuling.org> <8737btr6jb.fsf@skywalker.in.ibm.com> Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Thu, 2017-05-25 at 08:23 +0530, Aneesh Kumar K.V wrote: > Michael Neuling writes: >=20 > > On Wed, 2017-05-24 at 14:26 +0530, Aneesh Kumar K.V wrote: > > > Michael Neuling writes: > > >=20 > > > > Currently if you disable CONFIG_PPC_RADIX_MMU you'll crash on boot = on > > > > a P9. This is because we still set MMU_FTR_TYPE_RADIX via > > > > ibm,pa-features and MMU_FTR_TYPE_RADIX is what's used for code patc= hing > > > > in much of the asm code (ie. slb_miss_realmode) > > > >=20 > > > > This patch fixes the problem by stopping MMU_FTR_TYPE_RADIX from be= ing > > > > set from ibm.pa-features. > > > >=20 > > > > We may eventually end up removing the CONFIG_PPC_RADIX_MMU option > > > > completely but until then this fixes the issue. > > > >=20 > > > > Signed-off-by: Michael Neuling > > > > --- > > > > =C2=A0arch/powerpc/kernel/prom.c | 2 ++ > > > > =C2=A01 file changed, 2 insertions(+) > > > >=20 > > > > diff --git a/arch/powerpc/kernel/prom.c b/arch/powerpc/kernel/prom.= c > > > > index 40c4887c27..f830562974 100644 > > > > --- a/arch/powerpc/kernel/prom.c > > > > +++ b/arch/powerpc/kernel/prom.c > > > > @@ -161,7 +161,9 @@ static struct ibm_pa_feature { > > > > =C2=A0 { .pabyte =3D 0,=C2=A0=C2=A0.pabit =3D 3, .cpu_features=C2= =A0=C2=A0=3D CPU_FTR_CTRL }, > > > > =C2=A0 { .pabyte =3D 0,=C2=A0=C2=A0.pabit =3D 6, .cpu_features=C2= =A0=C2=A0=3D CPU_FTR_NOEXECUTE > > > > }, > > > > =C2=A0 { .pabyte =3D 1,=C2=A0=C2=A0.pabit =3D 2, .mmu_features=C2= =A0=C2=A0=3D > > > > MMU_FTR_CI_LARGE_PAGE > > > > }, > > > > +#ifdef CONFIG_PPC_RADIX_MMU > > > > =C2=A0 { .pabyte =3D 40, .pabit =3D 0, .mmu_features=C2=A0=C2=A0=3D= MMU_FTR_TYPE_RADIX > > > > }, > > > > +#endif > > > > =C2=A0 { .pabyte =3D 1,=C2=A0=C2=A0.pabit =3D 1, .invert =3D 1, .cp= u_features =3D > > > > CPU_FTR_NODSISRALIGN }, > > > > =C2=A0 { .pabyte =3D 5,=C2=A0=C2=A0.pabit =3D 0, .cpu_features=C2= =A0=C2=A0=3D CPU_FTR_REAL_LE, > > > > =C2=A0 =C2=A0=C2=A0=C2=A0=C2=A0.cpu_user_ftrs =3D > > > > PPC_FEATURE_TRUE_LE }, > > > > --=C2=A0 > > > > 2.11.0 > > >=20 > > > Instead can we do that feature removal in mmu_early_init_devtree. ie, > > > something like > >=20 > > It looks like mmu_early_init_devtree() gets called after parsing > > ibm,pa_features > > so that should work. > >=20 > > > diff --git a/arch/powerpc/mm/init_64.c b/arch/powerpc/mm/init_64.c > > > index 8f6f2a173e47..8f43f3827bac 100644 > > > --- a/arch/powerpc/mm/init_64.c > > > +++ b/arch/powerpc/mm/init_64.c > > > @@ -394,7 +394,7 @@ void __init mmu_early_init_devtree(v > > > oid) > > > =C2=A0{ > > > =C2=A0 /* Disable radix mode based on kernel command line. */ > > > =C2=A0 /* We don't yet have the machinery to do radix as a guest. */ > > > - if (disable_radix || !(mfmsr() & MSR_HV)) > > > > + if (!IS_ENABLED(CONFIG_PPC_RADIX_MMU) || disable_radix || > > > > !(mfmsr() & MSR_HV)) > >=20 > > What tree is this patch against?=C2=A0=C2=A0Linus' tree doesn't look li= ke that. > >=20 >=20 > mpe/next at the time of this merge window. Do you want me to send a > complete patch against latest mpe/next ? If you can test the broken case to make sure it fixes it... Sure! Thanks, Mikey