diff options
Diffstat (limited to 'Documentation/x86')
| -rw-r--r-- | Documentation/x86/00-INDEX | 4 | ||||
| -rw-r--r-- | Documentation/x86/boot.txt (renamed from Documentation/x86/i386/boot.txt) | 2 | ||||
| -rw-r--r-- | Documentation/x86/mtrr.txt | 305 | ||||
| -rw-r--r-- | Documentation/x86/pat.txt | 54 | ||||
| -rw-r--r-- | Documentation/x86/usb-legacy-support.txt (renamed from Documentation/x86/i386/usb-legacy-support.txt) | 0 | ||||
| -rw-r--r-- | Documentation/x86/x86_64/boot-options.txt | 4 | ||||
| -rw-r--r-- | Documentation/x86/zero-page.txt (renamed from Documentation/x86/i386/zero-page.txt) | 0 |
7 files changed, 355 insertions, 14 deletions
diff --git a/Documentation/x86/00-INDEX b/Documentation/x86/00-INDEX new file mode 100644 index 0000000..dbe3377 --- /dev/null +++ b/Documentation/x86/00-INDEX @@ -0,0 +1,4 @@ +00-INDEX + - this file +mtrr.txt + - how to use x86 Memory Type Range Registers to increase performance diff --git a/Documentation/x86/i386/boot.txt b/Documentation/x86/boot.txt index 147bfe5..83c0033 100644 --- a/Documentation/x86/i386/boot.txt +++ b/Documentation/x86/boot.txt @@ -308,7 +308,7 @@ Protocol: 2.00+ Field name: start_sys Type: read -Offset/size: 0x20c/4 +Offset/size: 0x20c/2 Protocol: 2.00+ The load low segment (0x1000). Obsolete. diff --git a/Documentation/x86/mtrr.txt b/Documentation/x86/mtrr.txt new file mode 100644 index 0000000..cc071dc --- /dev/null +++ b/Documentation/x86/mtrr.txt @@ -0,0 +1,305 @@ +MTRR (Memory Type Range Register) control +3 Jun 1999 +Richard Gooch +<rgooch@atnf.csiro.au> + + 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 <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <sys/types.h> +#include <sys/stat.h> +#include <fcntl.h> +#include <sys/ioctl.h> +#include <errno.h> +#include <asm/mtrr.h> + +#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 <stdio.h> +#include <string.h> +#include <stdlib.h> +#include <unistd.h> +#include <sys/types.h> +#include <sys/stat.h> +#include <fcntl.h> +#include <sys/ioctl.h> +#include <errno.h> +#include <asm/mtrr.h> + +#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/pat.txt b/Documentation/x86/pat.txt index 17965f9..c93ff5f 100644 --- a/Documentation/x86/pat.txt +++ b/Documentation/x86/pat.txt @@ -14,6 +14,10 @@ PAT allows for different types of memory attributes. The most commonly used ones that will be supported at this time are Write-back, Uncached, Write-combined and Uncached Minus. + +PAT APIs +-------- + There are many different APIs in the kernel that allows setting of memory attributes at the page level. In order to avoid aliasing, these interfaces should be used thoughtfully. Below is a table of interfaces available, @@ -26,38 +30,38 @@ address range to avoid any aliasing. API | RAM | ACPI,... | Reserved/Holes | -----------------------|----------|------------|------------------| | | | | -ioremap | -- | UC | UC | +ioremap | -- | UC- | UC- | | | | | ioremap_cache | -- | WB | WB | | | | | -ioremap_nocache | -- | UC | UC | +ioremap_nocache | -- | UC- | UC- | | | | | ioremap_wc | -- | -- | WC | | | | | -set_memory_uc | UC | -- | -- | +set_memory_uc | UC- | -- | -- | set_memory_wb | | | | | | | | set_memory_wc | WC | -- | -- | set_memory_wb | | | | | | | | -pci sysfs resource | -- | -- | UC | +pci sysfs resource | -- | -- | UC- | | | | | pci sysfs resource_wc | -- | -- | WC | is IORESOURCE_PREFETCH| | | | | | | | -pci proc | -- | -- | UC | +pci proc | -- | -- | UC- | !PCIIOC_WRITE_COMBINE | | | | | | | | pci proc | -- | -- | WC | PCIIOC_WRITE_COMBINE | | | | | | | | -/dev/mem | -- | UC | UC | +/dev/mem | -- | WB/WC/UC- | WB/WC/UC- | read-write | | | | | | | | -/dev/mem | -- | UC | UC | +/dev/mem | -- | UC- | UC- | mmap SYNC flag | | | | | | | | -/dev/mem | -- | WB/WC/UC | WB/WC/UC | +/dev/mem | -- | WB/WC/UC- | WB/WC/UC- | mmap !SYNC flag | |(from exist-| (from exist- | and | | ing alias)| ing alias) | any alias to this area| | | | @@ -68,7 +72,7 @@ pci proc | -- | -- | WC | and | | | | MTRR says WB | | | | | | | | -/dev/mem | -- | -- | UC_MINUS | +/dev/mem | -- | -- | UC- | mmap !SYNC flag | | | | no alias to this area | | | | and | | | | @@ -98,3 +102,35 @@ types. Drivers should use set_memory_[uc|wc] to set access type for RAM ranges. + +PAT debugging +------------- + +With CONFIG_DEBUG_FS enabled, PAT memtype list can be examined by + +# mount -t debugfs debugfs /sys/kernel/debug +# cat /sys/kernel/debug/x86/pat_memtype_list +PAT memtype list: +uncached-minus @ 0x7fadf000-0x7fae0000 +uncached-minus @ 0x7fb19000-0x7fb1a000 +uncached-minus @ 0x7fb1a000-0x7fb1b000 +uncached-minus @ 0x7fb1b000-0x7fb1c000 +uncached-minus @ 0x7fb1c000-0x7fb1d000 +uncached-minus @ 0x7fb1d000-0x7fb1e000 +uncached-minus @ 0x7fb1e000-0x7fb25000 +uncached-minus @ 0x7fb25000-0x7fb26000 +uncached-minus @ 0x7fb26000-0x7fb27000 +uncached-minus @ 0x7fb27000-0x7fb28000 +uncached-minus @ 0x7fb28000-0x7fb2e000 +uncached-minus @ 0x7fb2e000-0x7fb2f000 +uncached-minus @ 0x7fb2f000-0x7fb30000 +uncached-minus @ 0x7fb31000-0x7fb32000 +uncached-minus @ 0x80000000-0x90000000 + +This list shows physical address ranges and various PAT settings used to +access those physical address ranges. + +Another, more verbose way of getting PAT related debug messages is with +"debugpat" boot parameter. With this parameter, various debug messages are +printed to dmesg log. + diff --git a/Documentation/x86/i386/usb-legacy-support.txt b/Documentation/x86/usb-legacy-support.txt index 1894cdf..1894cdf 100644 --- a/Documentation/x86/i386/usb-legacy-support.txt +++ b/Documentation/x86/usb-legacy-support.txt diff --git a/Documentation/x86/x86_64/boot-options.txt b/Documentation/x86/x86_64/boot-options.txt index b0c7b6c..72ffb53 100644 --- a/Documentation/x86/x86_64/boot-options.txt +++ b/Documentation/x86/x86_64/boot-options.txt @@ -54,10 +54,6 @@ APICs apicmaintimer. Useful when your PIT timer is totally broken. - disable_8254_timer / enable_8254_timer - Enable interrupt 0 timer routing over the 8254 in addition to over - the IO-APIC. The kernel tries to set a sensible default. - Early Console syntax: earlyprintk=vga diff --git a/Documentation/x86/i386/zero-page.txt b/Documentation/x86/zero-page.txt index 169ad42..169ad42 100644 --- a/Documentation/x86/i386/zero-page.txt +++ b/Documentation/x86/zero-page.txt |
