From: Joakim Tjernlund <Joakim.Tjernlund@transmode.se> To: "christophe.leroy@c-s.fr" <christophe.leroy@c-s.fr> Cc: "scottwood@freescale.com" <scottwood@freescale.com>, "paulus@samba.org" <paulus@samba.org>, "mpe@ellerman.id.au" <mpe@ellerman.id.au>, "benh@kernel.crashing.org" <benh@kernel.crashing.org>, "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>, "linuxppc-dev@lists.ozlabs.org" <linuxppc-dev@lists.ozlabs.org> Subject: Re: [PATCH v3 2/2] powerpc/8xx: use _PAGE_RO instead of _PAGE_RW Date: Mon, 5 Jan 2015 18:12:00 +0000 [thread overview] Message-ID: <1420481520.25047.15.camel@transmode.se> (raw) In-Reply-To: <20141222101450.D7DD11A5E15@localhost.localdomain> On Mon, 2014-12-22 at 11:14 +0100, Christophe Leroy wrote: > On powerpc 8xx, in TLB entries, 0x400 bit is set to 1 for read-only pages > and is set to 0 for RW pages. So we should use _PAGE_RO instead of _PAGE_RW > > Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> Hi Christophe, been meaning to look over all you recent 8xx MMU/TLB patches but got so little time :( This is very cool (not sure if there will be a performance gain) but .. > > > > diff --git a/arch/powerpc/include/asm/pgtable-ppc32.h b/arch/powerpc/include/asm/pgtable-ppc32.h > index caf094a..b4e0c3b 100644 > --- a/arch/powerpc/include/asm/pgtable-ppc32.h > +++ b/arch/powerpc/include/asm/pgtable-ppc32.h > @@ -178,9 +178,10 @@ static inline unsigned long pte_update(pte_t *p, > andc %1,%0,%5\n\ > or %1,%1,%6\n\ > /* 0x200 == Extended encoding, bit 22 */ \ > - /* Bit 22 has to be 1 if neither _PAGE_USER nor _PAGE_RW are set */ \ > + /* Bit 22 has to be 1 when _PAGE_USER is unset and _PAGE_RO is set */ \ > rlwimi %1,%1,32-2,0x200\n /* get _PAGE_USER */ \ > - rlwinm %3,%1,32-1,0x200\n /* get _PAGE_RW */ \ > + rlwinm %3,%1,32-1,0x200\n /* get _PAGE_RO */ \ > + xori %3,%3,0x200\n \ > or %1,%3,%1\n\ > xori %1,%1,0x200\n" > " stwcx. %1,0,%4\n\ ... here I expected to loose the existing xori insn instead of adding one? Jocke
WARNING: multiple messages have this Message-ID (diff)
From: Joakim Tjernlund <Joakim.Tjernlund@transmode.se> To: "christophe.leroy@c-s.fr" <christophe.leroy@c-s.fr> Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>, "paulus@samba.org" <paulus@samba.org>, "scottwood@freescale.com" <scottwood@freescale.com>, "linuxppc-dev@lists.ozlabs.org" <linuxppc-dev@lists.ozlabs.org> Subject: Re: [PATCH v3 2/2] powerpc/8xx: use _PAGE_RO instead of _PAGE_RW Date: Mon, 5 Jan 2015 18:12:00 +0000 [thread overview] Message-ID: <1420481520.25047.15.camel@transmode.se> (raw) In-Reply-To: <20141222101450.D7DD11A5E15@localhost.localdomain> On Mon, 2014-12-22 at 11:14 +0100, Christophe Leroy wrote: > On powerpc 8xx, in TLB entries, 0x400 bit is set to 1 for read-only pages > and is set to 0 for RW pages. So we should use _PAGE_RO instead of _PAGE_= RW >=20 > Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> Hi Christophe, been meaning to look over all you recent 8xx MMU/TLB patches but got so little time :( This is very cool (not sure if there will be a performance gain) but .. >=20 >=20 >=20 > diff --git a/arch/powerpc/include/asm/pgtable-ppc32.h b/arch/powerpc/incl= ude/asm/pgtable-ppc32.h > index caf094a..b4e0c3b 100644 > --- a/arch/powerpc/include/asm/pgtable-ppc32.h > +++ b/arch/powerpc/include/asm/pgtable-ppc32.h > @@ -178,9 +178,10 @@ static inline unsigned long pte_update(pte_t *p, > andc %1,%0,%5\n\ > or %1,%1,%6\n\ > /* 0x200 =3D=3D Extended encoding, bit 22 */ \ > - /* Bit 22 has to be 1 if neither _PAGE_USER nor _PAGE_RW are set = */ \ > + /* Bit 22 has to be 1 when _PAGE_USER is unset and _PAGE_RO is se= t */ \ > rlwimi %1,%1,32-2,0x200\n /* get _PAGE_USER */ \ > - rlwinm %3,%1,32-1,0x200\n /* get _PAGE_RW */ \ > + rlwinm %3,%1,32-1,0x200\n /* get _PAGE_RO */ \ > + xori %3,%3,0x200\n \ > or %1,%3,%1\n\ > xori %1,%1,0x200\n" > " stwcx. %1,0,%4\n\ ... here I expected to loose the existing xori insn instead of adding one? Jocke=
next prev parent reply other threads:[~2015-01-05 18:21 UTC|newest] Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top 2014-12-22 10:14 [PATCH v3 2/2] powerpc/8xx: use _PAGE_RO instead of _PAGE_RW Christophe Leroy 2014-12-22 10:14 ` Christophe Leroy 2015-01-05 18:12 ` Joakim Tjernlund [this message] 2015-01-05 18:12 ` Joakim Tjernlund 2015-01-06 7:03 ` leroy christophe 2015-01-06 7:03 ` leroy christophe 2015-01-06 13:05 ` Joakim Tjernlund 2015-01-06 13:05 ` Joakim Tjernlund 2015-01-07 1:21 ` Scott Wood 2015-01-07 1:21 ` Scott Wood
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