From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6193DC43218 for ; Sat, 27 Apr 2019 17:32:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 06732206BB for ; Sat, 27 Apr 2019 17:32:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1556386351; bh=C9evFIF46v28MeG+yTwv1NnblJtSkmalMl4CMz+ttmA=; h=Date:From:To:Cc:Subject:In-Reply-To:References:List-ID:From; b=tiM7QLqZSeAY72o14ukNI/dBJL/m0wK5As3ah+CCTR1JMs2wW4G9aSP3Jl2CC5jMi 9/c9wHu2S+g4VKuZRzrMmUmRAvAk1frrrqZyQE/WaAE3MH570WnkQIVGqKqbLHMOAl 0pDwwSVVBoNbZCSw2LeE5rQgknQipHcsD0CgjjRo= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726333AbfD0Rc3 (ORCPT ); Sat, 27 Apr 2019 13:32:29 -0400 Received: from casper.infradead.org ([85.118.1.10]:49702 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725942AbfD0Rc2 (ORCPT ); Sat, 27 Apr 2019 13:32:28 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=Content-Transfer-Encoding:Content-Type: MIME-Version:References:In-Reply-To:Message-ID:Subject:Cc:To:From:Date:Sender :Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help: List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=bzh/vu50HGlbzqU0m2WTZFDuFlSNLrpk3hMuAlpUess=; b=Fc1ENnwHrGy/9lNQr5RNQo6zFv LXIK3WfGkHvcGzwHeAQZTeAOsUv15htQVCX9ftHj4sfZv6z7CGHmz9djB5gMhG2uxu7Y4NSDQ3ABW GAVoOJrXng1lc2KgAday+j1yGceZLAKQs2GjAVHLTeJLBke2tZBfM13GyuAiLICVMAm/9hFRwEqFA AbmUuwQjL8SiPMrfBfwhqzlDygZ5j7rnNclPb1BFLk5Br+JD3bovThzwuc64NfLmaTJC6BU+WVV8W JAxj6Wsws5O7KBdfdnUKI0DuNcfHGhkatGcI6rwxEZxba5dzm3ZFVH5Sdh/kken37tGP7tza7exwR jl6+0Q/Q==; Received: from 177.17.250.151.dynamic.adsl.gvt.net.br ([177.17.250.151] helo=coco.lan) by casper.infradead.org with esmtpsa (Exim 4.90_1 #2 (Red Hat Linux)) id 1hKRBT-0002BI-NH; Sat, 27 Apr 2019 17:32:20 +0000 Date: Sat, 27 Apr 2019 14:32:13 -0300 From: Mauro Carvalho Chehab To: Changbin Du Cc: Jonathan Corbet , tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, x86@kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 10/27] Documentation: x86: convert mtrr.txt to reST Message-ID: <20190427143213.3c0d2286@coco.lan> In-Reply-To: <20190426153150.21228-11-changbin.du@gmail.com> References: <20190426153150.21228-1-changbin.du@gmail.com> <20190426153150.21228-11-changbin.du@gmail.com> X-Mailer: Claws Mail 3.17.3 (GTK+ 2.24.32; x86_64-redhat-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Em Fri, 26 Apr 2019 23:31:33 +0800 Changbin Du escreveu: > This converts the plain text documentation to reStructuredText format and > add it to Sphinx TOC tree. No essential content change. > > Signed-off-by: Changbin Du > --- > Documentation/x86/index.rst | 1 + > Documentation/x86/mtrr.rst | 350 ++++++++++++++++++++++++++++++++++++ > Documentation/x86/mtrr.txt | 329 --------------------------------- > 3 files changed, 351 insertions(+), 329 deletions(-) > create mode 100644 Documentation/x86/mtrr.rst > delete mode 100644 Documentation/x86/mtrr.txt > > diff --git a/Documentation/x86/index.rst b/Documentation/x86/index.rst > index fd54b859db9b..d805962a7238 100644 > --- a/Documentation/x86/index.rst > +++ b/Documentation/x86/index.rst > @@ -16,3 +16,4 @@ Linux x86 Support > earlyprintk > zero-page > tlb > + mtrr > diff --git a/Documentation/x86/mtrr.rst b/Documentation/x86/mtrr.rst > new file mode 100644 > index 000000000000..72da61022861 > --- /dev/null > +++ b/Documentation/x86/mtrr.rst > @@ -0,0 +1,350 @@ > +.. SPDX-License-Identifier: GPL-2.0 > + > +========================================= > +MTRR (Memory Type Range Register) control > +========================================= > + > +:Ahthors: - Richard Gooch - 3 Jun 1999 > + - Luis R. Rodriguez - April 9, 2015 Typo: Authors > + > + > +Phasing out MTRR use > +==================== > + > +MTRR use is replaced on modern x86 hardware with PAT. Direct MTRR use by > +drivers on Linux is now completely phased out, device drivers should use > +arch_phys_wc_add() in combination with ioremap_wc() to make MTRR effective on > +non-PAT systems while a no-op but equally effective on PAT enabled systems. > + > +Even if Linux does not use MTRRs directly, some x86 platform firmware may still > +set up MTRRs early before booting the OS. They do this as some platform > +firmware may still have implemented access to MTRRs which would be controlled > +and handled by the platform firmware directly. An example of platform use of > +MTRRs is through the use of SMI handlers, one case could be for fan control, > +the platform code would need uncachable access to some of its fan control > +registers. Such platform access does not need any Operating System MTRR code in > +place other than mtrr_type_lookup() to ensure any OS specific mapping requests > +are aligned with platform MTRR setup. If MTRRs are only set up by the platform > +firmware code though and the OS does not make any specific MTRR mapping > +requests mtrr_type_lookup() should always return MTRR_TYPE_INVALID. > + > +For details refer to :doc:`x86/pat`. I'm in doubt about the block below: > + > +On Intel P6 family processors (Pentium Pro, Pentium II and later) > +the Memory Type Range Registers (MTRRs) may be used to control > +processor access to memory ranges. This is most useful when you have > +a video (VGA) card on a PCI or AGP bus. Enabling write-combining > +allows bus write transfers to be combined into a larger transfer > +before bursting over the PCI/AGP bus. This can increase performance > +of image write operations 2.5 times or more. > + > +The Cyrix 6x86, 6x86MX and M II processors have Address Range > +Registers (ARRs) which provide a similar functionality to MTRRs. For > +these, the ARRs are used to emulate the MTRRs. > + > +The AMD K6-2 (stepping 8 and above) and K6-3 processors have two > +MTRRs. These are supported. The AMD Athlon family provide 8 Intel > +style MTRRs. > + > +The Centaur C6 (WinChip) has 8 MCRs, allowing write-combining. These > +are supported. > + > +The VIA Cyrix III and VIA C3 CPUs offer 8 Intel style MTRRs. > + > +The CONFIG_MTRR option creates a /proc/mtrr file which may be used > +to manipulate your MTRRs. Typically the X server should use > +this. This should have a reasonably generic interface so that > +similar control registers on other processors can be easily > +supported. All the above were originally indented, and marked by an horizontal bar (together with the next paragraph). Perhaps the intention there were to mark them as some sort of per-CPU type notes. Anyway, I would preserve the original indentation - possibly replacing the horizontal bar using non-ReST standard: =============================================================================== By the ReST equivalent: ------------------------------------------------------------------------------- Later, if x86 maintainers thing it is worth, they could add a note markup before the block. > + > +There are two interfaces to /proc/mtrr: one is an ASCII interface > +which allows you to read and write. The other is an ioctl() > +interface. The ASCII interface is meant for administration. The > +ioctl() interface is meant for C programs (i.e. the X server). The > +interfaces are described below, with sample commands and C code. > + > +Reading MTRRs from the shell:: > + > + % cat /proc/mtrr > + reg00: base=0x00000000 ( 0MB), size= 128MB: write-back, count=1 > + reg01: base=0x08000000 ( 128MB), size= 64MB: write-back, count=1 > + > +Creating MTRRs from the C-shell:: > + > + # echo "base=0xf8000000 size=0x400000 type=write-combining" >! /proc/mtrr > + > +or if you use bash:: > + > + # echo "base=0xf8000000 size=0x400000 type=write-combining" >| /proc/mtrr > + > +And the result thereof:: > + > + % cat /proc/mtrr > + reg00: base=0x00000000 ( 0MB), size= 128MB: write-back, count=1 > + reg01: base=0x08000000 ( 128MB), size= 64MB: write-back, count=1 > + reg02: base=0xf8000000 (3968MB), size= 4MB: write-combining, count=1 > + > +This is for video RAM at base address 0xf8000000 and size 4 megabytes. To > +find out your base address, you need to look at the output of your X > +server, which tells you where the linear framebuffer address is. A > +typical line that you may get is: > + > +(--) S3: PCI: 968 rev 0, Linear FB @ 0xf8000000 > + > +Note that you should only use the value from the X server, as it may > +move the framebuffer base address, so the only value you can trust is > +that reported by the X server. > + > +To find out the size of your framebuffer (what, you don't actually > +know?), the following line will tell you: > + > +(--) S3: videoram: 4096k > + > +That's 4 megabytes, which is 0x400000 bytes (in hexadecimal). > +A patch is being written for XFree86 which will make this automatic: > +in other words the X server will manipulate /proc/mtrr using the > +ioctl() interface, so users won't have to do anything. If you use a > +commercial X server, lobby your vendor to add support for MTRRs. > + > + > +Creating overlapping MTRRs > +========================== > +:: > + > + %echo "base=0xfb000000 size=0x1000000 type=write-combining" >/proc/mtrr > + %echo "base=0xfb000000 size=0x1000 type=uncachable" >/proc/mtrr > + > +And the results:: > + > + % cat /proc/mtrr > + reg00: base=0x00000000 ( 0MB), size= 64MB: write-back, count=1 > + reg01: base=0xfb000000 (4016MB), size= 16MB: write-combining, count=1 > + reg02: base=0xfb000000 (4016MB), size= 4kB: uncachable, count=1 > + > +Some cards (especially Voodoo Graphics boards) need this 4 kB area > +excluded from the beginning of the region because it is used for > +registers. > + > +NOTE: You can only create type=uncachable region, if the first > +region that you created is type=write-combining. If you don't want to use a note markup, I would, at least, do: Note: You can only create type=uncachable region, if the first region that you created is type=write-combining. > + > + > +Removing MTRRs from the C-shel > +============================== There's also a typo above: C-shel -> C-shell... > +:: > + > + % echo "disable=2" >! /proc/mtrr > + > +or using bash:: > + > + % echo "disable=2" >| /proc/mtrr Yet, I would, instead rewrite this block as: Removing MTRRs ============== Using C-shell:: % echo "disable=2" >! /proc/mtrr or using bash:: % echo "disable=2" >| /proc/mtrr As it contains both csh and bash instructions there. > + > + > +Reading MTRRs from a C program using ioctl()'s > +============================================== > +:: > + > + /* mtrr-show.c > + > + Source file for mtrr-show (example program to show MTRRs using ioctl()'s) > + > + Copyright (C) 1997-1998 Richard Gooch > + > + This program is free software; you can redistribute it and/or modify > + it under the terms of the GNU General Public License as published by > + the Free Software Foundation; either version 2 of the License, or > + (at your option) any later version. > + > + This program is distributed in the hope that it will be useful, > + but WITHOUT ANY WARRANTY; without even the implied warranty of > + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the > + GNU General Public License for more details. > + > + You should have received a copy of the GNU General Public License > + along with this program; if not, write to the Free Software > + Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. > + > + Richard Gooch may be reached by email at rgooch@atnf.csiro.au > + The postal address is: > + Richard Gooch, c/o ATNF, P. O. Box 76, Epping, N.S.W., 2121, Australia. > + */ > + > + /* > + This program will use an ioctl() on /proc/mtrr to show the current MTRR > + settings. This is an alternative to reading /proc/mtrr. > + > + > + Written by Richard Gooch 17-DEC-1997 > + > + Last updated by Richard Gooch 2-MAY-1998 > + > + > + */ > + #include > + #include > + #include > + #include > + #include > + #include > + #include > + #include > + #include > + > + #define TRUE 1 > + #define FALSE 0 > + #define ERRSTRING strerror (errno) > + > + static char *mtrr_strings[MTRR_NUM_TYPES] = > + { > + "uncachable", /* 0 */ > + "write-combining", /* 1 */ > + "?", /* 2 */ > + "?", /* 3 */ > + "write-through", /* 4 */ > + "write-protect", /* 5 */ > + "write-back", /* 6 */ > + }; > + > + int main () > + { > + int fd; > + struct mtrr_gentry gentry; > + > + if ( ( fd = open ("/proc/mtrr", O_RDONLY, 0) ) == -1 ) > + { > + if (errno == ENOENT) > + { > + fputs ("/proc/mtrr not found: not supported or you don't have a PPro?\n", > + stderr); > + exit (1); > + } > + fprintf (stderr, "Error opening /proc/mtrr\t%s\n", ERRSTRING); > + exit (2); > + } > + for (gentry.regnum = 0; ioctl (fd, MTRRIOC_GET_ENTRY, &gentry) == 0; > + ++gentry.regnum) > + { > + if (gentry.size < 1) > + { > + fprintf (stderr, "Register: %u disabled\n", gentry.regnum); > + continue; > + } > + fprintf (stderr, "Register: %u base: 0x%lx size: 0x%lx type: %s\n", > + gentry.regnum, gentry.base, gentry.size, > + mtrr_strings[gentry.type]); > + } > + if (errno == EINVAL) exit (0); > + fprintf (stderr, "Error doing ioctl(2) on /dev/mtrr\t%s\n", ERRSTRING); > + exit (3); > + } /* End Function main */ > + > + > +Creating MTRRs from a C programme using ioctl()'s > +================================================= > +:: > + > + /* mtrr-add.c > + > + Source file for mtrr-add (example programme to add an MTRRs using ioctl()) > + > + Copyright (C) 1997-1998 Richard Gooch > + > + This program is free software; you can redistribute it and/or modify > + it under the terms of the GNU General Public License as published by > + the Free Software Foundation; either version 2 of the License, or > + (at your option) any later version. > + > + This program is distributed in the hope that it will be useful, > + but WITHOUT ANY WARRANTY; without even the implied warranty of > + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the > + GNU General Public License for more details. > + > + You should have received a copy of the GNU General Public License > + along with this program; if not, write to the Free Software > + Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. > + > + Richard Gooch may be reached by email at rgooch@atnf.csiro.au > + The postal address is: > + Richard Gooch, c/o ATNF, P. O. Box 76, Epping, N.S.W., 2121, Australia. > + */ > + > + /* > + This programme will use an ioctl() on /proc/mtrr to add an entry. The first > + available mtrr is used. This is an alternative to writing /proc/mtrr. > + > + > + Written by Richard Gooch 17-DEC-1997 > + > + Last updated by Richard Gooch 2-MAY-1998 > + > + > + */ > + #include > + #include > + #include > + #include > + #include > + #include > + #include > + #include > + #include > + #include > + > + #define TRUE 1 > + #define FALSE 0 > + #define ERRSTRING strerror (errno) > + > + static char *mtrr_strings[MTRR_NUM_TYPES] = > + { > + "uncachable", /* 0 */ > + "write-combining", /* 1 */ > + "?", /* 2 */ > + "?", /* 3 */ > + "write-through", /* 4 */ > + "write-protect", /* 5 */ > + "write-back", /* 6 */ > + }; > + > + int main (int argc, char **argv) > + { > + int fd; > + struct mtrr_sentry sentry; > + > + if (argc != 4) > + { > + fprintf (stderr, "Usage:\tmtrr-add base size type\n"); > + exit (1); > + } > + sentry.base = strtoul (argv[1], NULL, 0); > + sentry.size = strtoul (argv[2], NULL, 0); > + for (sentry.type = 0; sentry.type < MTRR_NUM_TYPES; ++sentry.type) > + { > + if (strcmp (argv[3], mtrr_strings[sentry.type]) == 0) break; > + } > + if (sentry.type >= MTRR_NUM_TYPES) > + { > + fprintf (stderr, "Illegal type: \"%s\"\n", argv[3]); > + exit (2); > + } > + if ( ( fd = open ("/proc/mtrr", O_WRONLY, 0) ) == -1 ) > + { > + if (errno == ENOENT) > + { > + fputs ("/proc/mtrr not found: not supported or you don't have a PPro?\n", > + stderr); > + exit (3); > + } > + fprintf (stderr, "Error opening /proc/mtrr\t%s\n", ERRSTRING); > + exit (4); > + } > + if (ioctl (fd, MTRRIOC_ADD_ENTRY, &sentry) == -1) > + { > + fprintf (stderr, "Error doing ioctl(2) on /dev/mtrr\t%s\n", ERRSTRING); > + exit (5); > + } > + fprintf (stderr, "Sleeping for 5 seconds so you can see the new entry\n"); > + sleep (5); > + close (fd); > + fputs ("I've just closed /proc/mtrr so now the new entry should be gone\n", > + stderr); > + } /* End Function main */ > diff --git a/Documentation/x86/mtrr.txt b/Documentation/x86/mtrr.txt > deleted file mode 100644 > index dc3e703913ac..000000000000 > --- a/Documentation/x86/mtrr.txt > +++ /dev/null > @@ -1,329 +0,0 @@ > -MTRR (Memory Type Range Register) control > - > -Richard Gooch - 3 Jun 1999 > -Luis R. Rodriguez - April 9, 2015 > - > -=============================================================================== > -Phasing out MTRR use > - > -MTRR use is replaced on modern x86 hardware with PAT. Direct MTRR use by > -drivers on Linux is now completely phased out, device drivers should use > -arch_phys_wc_add() in combination with ioremap_wc() to make MTRR effective on > -non-PAT systems while a no-op but equally effective on PAT enabled systems. > - > -Even if Linux does not use MTRRs directly, some x86 platform firmware may still > -set up MTRRs early before booting the OS. They do this as some platform > -firmware may still have implemented access to MTRRs which would be controlled > -and handled by the platform firmware directly. An example of platform use of > -MTRRs is through the use of SMI handlers, one case could be for fan control, > -the platform code would need uncachable access to some of its fan control > -registers. Such platform access does not need any Operating System MTRR code in > -place other than mtrr_type_lookup() to ensure any OS specific mapping requests > -are aligned with platform MTRR setup. If MTRRs are only set up by the platform > -firmware code though and the OS does not make any specific MTRR mapping > -requests mtrr_type_lookup() should always return MTRR_TYPE_INVALID. > - > -For details refer to Documentation/x86/pat.txt. > - > -=============================================================================== > - > - On Intel P6 family processors (Pentium Pro, Pentium II and later) > - the Memory Type Range Registers (MTRRs) may be used to control > - processor access to memory ranges. This is most useful when you have > - a video (VGA) card on a PCI or AGP bus. Enabling write-combining > - allows bus write transfers to be combined into a larger transfer > - before bursting over the PCI/AGP bus. This can increase performance > - of image write operations 2.5 times or more. > - > - The Cyrix 6x86, 6x86MX and M II processors have Address Range > - Registers (ARRs) which provide a similar functionality to MTRRs. For > - these, the ARRs are used to emulate the MTRRs. > - > - The AMD K6-2 (stepping 8 and above) and K6-3 processors have two > - MTRRs. These are supported. The AMD Athlon family provide 8 Intel > - style MTRRs. > - > - The Centaur C6 (WinChip) has 8 MCRs, allowing write-combining. These > - are supported. > - > - The VIA Cyrix III and VIA C3 CPUs offer 8 Intel style MTRRs. > - > - The CONFIG_MTRR option creates a /proc/mtrr file which may be used > - to manipulate your MTRRs. Typically the X server should use > - this. This should have a reasonably generic interface so that > - similar control registers on other processors can be easily > - supported. > - > - > -There are two interfaces to /proc/mtrr: one is an ASCII interface > -which allows you to read and write. The other is an ioctl() > -interface. The ASCII interface is meant for administration. The > -ioctl() interface is meant for C programs (i.e. the X server). The > -interfaces are described below, with sample commands and C code. > - > -=============================================================================== > -Reading MTRRs from the shell: > - > -% cat /proc/mtrr > -reg00: base=0x00000000 ( 0MB), size= 128MB: write-back, count=1 > -reg01: base=0x08000000 ( 128MB), size= 64MB: write-back, count=1 > -=============================================================================== > -Creating MTRRs from the C-shell: > -# echo "base=0xf8000000 size=0x400000 type=write-combining" >! /proc/mtrr > -or if you use bash: > -# echo "base=0xf8000000 size=0x400000 type=write-combining" >| /proc/mtrr > - > -And the result thereof: > -% cat /proc/mtrr > -reg00: base=0x00000000 ( 0MB), size= 128MB: write-back, count=1 > -reg01: base=0x08000000 ( 128MB), size= 64MB: write-back, count=1 > -reg02: base=0xf8000000 (3968MB), size= 4MB: write-combining, count=1 > - > -This is for video RAM at base address 0xf8000000 and size 4 megabytes. To > -find out your base address, you need to look at the output of your X > -server, which tells you where the linear framebuffer address is. A > -typical line that you may get is: > - > -(--) S3: PCI: 968 rev 0, Linear FB @ 0xf8000000 > - > -Note that you should only use the value from the X server, as it may > -move the framebuffer base address, so the only value you can trust is > -that reported by the X server. > - > -To find out the size of your framebuffer (what, you don't actually > -know?), the following line will tell you: > - > -(--) S3: videoram: 4096k > - > -That's 4 megabytes, which is 0x400000 bytes (in hexadecimal). > -A patch is being written for XFree86 which will make this automatic: > -in other words the X server will manipulate /proc/mtrr using the > -ioctl() interface, so users won't have to do anything. If you use a > -commercial X server, lobby your vendor to add support for MTRRs. > -=============================================================================== > -Creating overlapping MTRRs: > - > -%echo "base=0xfb000000 size=0x1000000 type=write-combining" >/proc/mtrr > -%echo "base=0xfb000000 size=0x1000 type=uncachable" >/proc/mtrr > - > -And the results: cat /proc/mtrr > -reg00: base=0x00000000 ( 0MB), size= 64MB: write-back, count=1 > -reg01: base=0xfb000000 (4016MB), size= 16MB: write-combining, count=1 > -reg02: base=0xfb000000 (4016MB), size= 4kB: uncachable, count=1 > - > -Some cards (especially Voodoo Graphics boards) need this 4 kB area > -excluded from the beginning of the region because it is used for > -registers. > - > -NOTE: You can only create type=uncachable region, if the first > -region that you created is type=write-combining. > -=============================================================================== > -Removing MTRRs from the C-shell: > -% echo "disable=2" >! /proc/mtrr > -or using bash: > -% echo "disable=2" >| /proc/mtrr > -=============================================================================== > -Reading MTRRs from a C program using ioctl()'s: > - > -/* mtrr-show.c > - > - Source file for mtrr-show (example program to show MTRRs using ioctl()'s) > - > - Copyright (C) 1997-1998 Richard Gooch > - > - This program is free software; you can redistribute it and/or modify > - it under the terms of the GNU General Public License as published by > - the Free Software Foundation; either version 2 of the License, or > - (at your option) any later version. > - > - This program is distributed in the hope that it will be useful, > - but WITHOUT ANY WARRANTY; without even the implied warranty of > - MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the > - GNU General Public License for more details. > - > - You should have received a copy of the GNU General Public License > - along with this program; if not, write to the Free Software > - Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. > - > - Richard Gooch may be reached by email at rgooch@atnf.csiro.au > - The postal address is: > - Richard Gooch, c/o ATNF, P. O. Box 76, Epping, N.S.W., 2121, Australia. > -*/ > - > -/* > - This program will use an ioctl() on /proc/mtrr to show the current MTRR > - settings. This is an alternative to reading /proc/mtrr. > - > - > - Written by Richard Gooch 17-DEC-1997 > - > - Last updated by Richard Gooch 2-MAY-1998 > - > - > -*/ > -#include > -#include > -#include > -#include > -#include > -#include > -#include > -#include > -#include > - > -#define TRUE 1 > -#define FALSE 0 > -#define ERRSTRING strerror (errno) > - > -static char *mtrr_strings[MTRR_NUM_TYPES] = > -{ > - "uncachable", /* 0 */ > - "write-combining", /* 1 */ > - "?", /* 2 */ > - "?", /* 3 */ > - "write-through", /* 4 */ > - "write-protect", /* 5 */ > - "write-back", /* 6 */ > -}; > - > -int main () > -{ > - int fd; > - struct mtrr_gentry gentry; > - > - if ( ( fd = open ("/proc/mtrr", O_RDONLY, 0) ) == -1 ) > - { > - if (errno == ENOENT) > - { > - fputs ("/proc/mtrr not found: not supported or you don't have a PPro?\n", > - stderr); > - exit (1); > - } > - fprintf (stderr, "Error opening /proc/mtrr\t%s\n", ERRSTRING); > - exit (2); > - } > - for (gentry.regnum = 0; ioctl (fd, MTRRIOC_GET_ENTRY, &gentry) == 0; > - ++gentry.regnum) > - { > - if (gentry.size < 1) > - { > - fprintf (stderr, "Register: %u disabled\n", gentry.regnum); > - continue; > - } > - fprintf (stderr, "Register: %u base: 0x%lx size: 0x%lx type: %s\n", > - gentry.regnum, gentry.base, gentry.size, > - mtrr_strings[gentry.type]); > - } > - if (errno == EINVAL) exit (0); > - fprintf (stderr, "Error doing ioctl(2) on /dev/mtrr\t%s\n", ERRSTRING); > - exit (3); > -} /* End Function main */ > -=============================================================================== > -Creating MTRRs from a C programme using ioctl()'s: > - > -/* mtrr-add.c > - > - Source file for mtrr-add (example programme to add an MTRRs using ioctl()) > - > - Copyright (C) 1997-1998 Richard Gooch > - > - This program is free software; you can redistribute it and/or modify > - it under the terms of the GNU General Public License as published by > - the Free Software Foundation; either version 2 of the License, or > - (at your option) any later version. > - > - This program is distributed in the hope that it will be useful, > - but WITHOUT ANY WARRANTY; without even the implied warranty of > - MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the > - GNU General Public License for more details. > - > - You should have received a copy of the GNU General Public License > - along with this program; if not, write to the Free Software > - Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. > - > - Richard Gooch may be reached by email at rgooch@atnf.csiro.au > - The postal address is: > - Richard Gooch, c/o ATNF, P. O. Box 76, Epping, N.S.W., 2121, Australia. > -*/ > - > -/* > - This programme will use an ioctl() on /proc/mtrr to add an entry. The first > - available mtrr is used. This is an alternative to writing /proc/mtrr. > - > - > - Written by Richard Gooch 17-DEC-1997 > - > - Last updated by Richard Gooch 2-MAY-1998 > - > - > -*/ > -#include > -#include > -#include > -#include > -#include > -#include > -#include > -#include > -#include > -#include > - > -#define TRUE 1 > -#define FALSE 0 > -#define ERRSTRING strerror (errno) > - > -static char *mtrr_strings[MTRR_NUM_TYPES] = > -{ > - "uncachable", /* 0 */ > - "write-combining", /* 1 */ > - "?", /* 2 */ > - "?", /* 3 */ > - "write-through", /* 4 */ > - "write-protect", /* 5 */ > - "write-back", /* 6 */ > -}; > - > -int main (int argc, char **argv) > -{ > - int fd; > - struct mtrr_sentry sentry; > - > - if (argc != 4) > - { > - fprintf (stderr, "Usage:\tmtrr-add base size type\n"); > - exit (1); > - } > - sentry.base = strtoul (argv[1], NULL, 0); > - sentry.size = strtoul (argv[2], NULL, 0); > - for (sentry.type = 0; sentry.type < MTRR_NUM_TYPES; ++sentry.type) > - { > - if (strcmp (argv[3], mtrr_strings[sentry.type]) == 0) break; > - } > - if (sentry.type >= MTRR_NUM_TYPES) > - { > - fprintf (stderr, "Illegal type: \"%s\"\n", argv[3]); > - exit (2); > - } > - if ( ( fd = open ("/proc/mtrr", O_WRONLY, 0) ) == -1 ) > - { > - if (errno == ENOENT) > - { > - fputs ("/proc/mtrr not found: not supported or you don't have a PPro?\n", > - stderr); > - exit (3); > - } > - fprintf (stderr, "Error opening /proc/mtrr\t%s\n", ERRSTRING); > - exit (4); > - } > - if (ioctl (fd, MTRRIOC_ADD_ENTRY, &sentry) == -1) > - { > - fprintf (stderr, "Error doing ioctl(2) on /dev/mtrr\t%s\n", ERRSTRING); > - exit (5); > - } > - fprintf (stderr, "Sleeping for 5 seconds so you can see the new entry\n"); > - sleep (5); > - close (fd); > - fputs ("I've just closed /proc/mtrr so now the new entry should be gone\n", > - stderr); > -} /* End Function main */ > -=============================================================================== Thanks, Mauro