Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754408Ab3IKWhN (ORCPT ); Wed, 11 Sep 2013 18:37:13 -0400 Received: from am1ehsobe003.messaging.microsoft.com ([213.199.154.206]:39210 "EHLO am1outboundpool.messaging.microsoft.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751313Ab3IKWhG (ORCPT ); Wed, 11 Sep 2013 18:37:06 -0400 X-Forefront-Antispam-Report: CIP:70.37.183.190;KIP:(null);UIP:(null);IPV:NLI;H:mail.freescale.net;RD:none;EFVD:NLI X-SpamScore: -3 X-BigFish: VS-3(zz98dI936eI1432Izz1f42h208ch1ee6h1de0h1fdah2073h1202h1e76h1d1ah1d2ah1fc6hzz1de098h1de097h8275dhz2dh2a8h839h93fhd24hf0ah1288h12a5h12a9h12bdh137ah139eh13b6h1441h1504h1537h162dh1631h1758h1898h18e1h1946h19b5h1ad9h1b0ah1b2fh1fb3h1d0ch1d2eh1d3fh1dfeh1dffh1e23h1fe8h1ff5h1155h) Message-ID: <1378939017.12204.409.camel@snotra.buserror.net> Subject: Re: [PATCH] powerpc 8xx: Fixing issue with CONFIG_PIN_TLB From: Scott Wood To: Christophe Leroy CC: Benjamin Herrenschmidt , Paul Mackerras , , Date: Wed, 11 Sep 2013 17:36:57 -0500 In-Reply-To: <201309111644.r8BGiuDZ016325@localhost.localdomain> References: <201309111644.r8BGiuDZ016325@localhost.localdomain> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.6.4-0ubuntu1 MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-OriginatorOrg: freescale.com X-FOPE-CONNECTOR: Id%0$Dn%*$RO%0$TLS%0$FQDN%$TlsDn% Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1651 Lines: 41 On Wed, 2013-09-11 at 18:44 +0200, Christophe Leroy wrote: > Activating CONFIG_PIN_TLB is supposed to pin the IMMR and the first three > 8Mbytes pages. But the setting of the MD_CTR was missing so as the index is > decremented every DTLB update, the pinning of the third 8Mbytes page was > overwriting the DTLB entry for IMMR. > > Signed-off-by: Christophe Leroy > > diff -ur linux-3.11.org/arch/powerpc/kernel/head_8xx.S linux-3.11/arch/powerpc/kernel/head_8xx.S > --- linux-3.11.org/arch/powerpc/kernel/head_8xx.S 2013-09-02 22:46:10.000000000 +0200 > +++ linux-3.11/arch/powerpc/kernel/head_8xx.S 2013-09-09 11:28:54.000000000 +0200 > @@ -862,6 +862,9 @@ > addis r11, r11, 0x0080 /* Add 8M */ > mtspr SPRN_MD_RPN, r11 > > + addi r10, r10, 0x0100 > + mtspr SPRN_MD_CTR, r10 > + > addis r8, r8, 0x0080 /* Add 8M */ > mtspr SPRN_MD_EPN, r8 > mtspr SPRN_MD_TWC, r9 I wonder why we don't start from entry 31 so we can actually make use of that autodecrement. What will happen when we load the first normal TLB entry later on? I don't see any setting of SPRN_MD_CTR after this code, so won't it overwrite entry 30 (the middle 8M) in the CONFIG_PIN_TLB case? Ben, would patches like this be considered bugfixes as far as merging goes, or would they be for next given that it's something that's never really worked right and hasn't been touched in years? -Scott -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/