€•}„      Œsphinx.addnodes”Œdocument”“”)”}”(Œ	rawsource”Œ ”Œchildren”]”(Œtranslations”ŒLanguagesNode”“”)”}”(hhh]”(h Œpending_xref”“”)”}”(hhh]”Œdocutils.nodes”ŒText”“”ŒChinese (Simplified)”…””}”Œparent”hsbaŒ
attributes”}”(Œids”]”Œclasses”]”Œnames”]”Œdupnames”]”Œbackrefs”]”Œ	refdomain”Œstd”Œreftype”Œdoc”Œ	reftarget”Œ!/translations/zh_CN/arch/x86/mtrr”Œmodname”NŒ	classname”NŒrefexplicit”ˆuŒtagname”hhhubh)”}”(hhh]”hŒChinese (Traditional)”…””}”hh2sbah}”(h]”h ]”h"]”h$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ!/translations/zh_TW/arch/x86/mtrr”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubh)”}”(hhh]”hŒItalian”…””}”hhFsbah}”(h]”h ]”h"]”h$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ!/translations/it_IT/arch/x86/mtrr”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubh)”}”(hhh]”hŒJapanese”…””}”hhZsbah}”(h]”h ]”h"]”h$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ!/translations/ja_JP/arch/x86/mtrr”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubh)”}”(hhh]”hŒKorean”…””}”hhnsbah}”(h]”h ]”h"]”h$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ!/translations/ko_KR/arch/x86/mtrr”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubh)”}”(hhh]”hŒPortuguese (Brazilian)”…””}”hh‚sbah}”(h]”h ]”h"]”h$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ!/translations/pt_BR/arch/x86/mtrr”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubh)”}”(hhh]”hŒSpanish”…””}”hh–sbah}”(h]”h ]”h"]”h$]”h&]”Œ	refdomain”h)Œreftype”h+Œ	reftarget”Œ!/translations/sp_SP/arch/x86/mtrr”Œmodname”NŒ	classname”NŒrefexplicit”ˆuh1hhhubeh}”(h]”h ]”h"]”h$]”h&]”Œcurrent_language”ŒEnglish”uh1h
hhŒ	_document”hŒsource”NŒline”NubhŒcomment”“”)”}”(hŒ SPDX-License-Identifier: GPL-2.0”h]”hŒ SPDX-License-Identifier: GPL-2.0”…””}”hh·sbah}”(h]”h ]”h"]”h$]”h&]”Œ	xml:space”Œpreserve”uh1hµhhh²hh³Œ;/var/lib/git/docbuild/linux/Documentation/arch/x86/mtrr.rst”h´KubhŒsection”“”)”}”(hhh]”(hŒtitle”“”)”}”(hŒ)MTRR (Memory Type Range Register) control”h]”hŒ)MTRR (Memory Type Range Register) control”…””}”(hhÏh²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÍhhÊh²hh³hÇh´KubhŒ
field_list”“”)”}”(hhh]”hŒfield”“”)”}”(hhh]”(hŒ
field_name”“”)”}”(hŒAuthors”h]”hŒAuthors”…””}”(hhéh²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hçhhäh³hÇh´K ubhŒ
field_body”“”)”}”(hŒs- Richard Gooch <rgooch@atnf.csiro.au> - 3 Jun 1999
- Luis R. Rodriguez <mcgrof@do-not-panic.com> - April 9, 2015

”h]”hŒbullet_list”“”)”}”(hhh]”(hŒ	list_item”“”)”}”(hŒ1Richard Gooch <rgooch@atnf.csiro.au> - 3 Jun 1999”h]”hŒ	paragraph”“”)”}”(hj  h]”(hŒRichard Gooch <”…””}”(hj
  h²hh³Nh´NubhŒ	reference”“”)”}”(hŒrgooch@atnf.csiro.au”h]”hŒrgooch@atnf.csiro.au”…””}”(hj  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”Œrefuri”Œmailto:rgooch@atnf.csiro.au”uh1j  hj
  ubhŒ> - 3 Jun 1999”…””}”(hj
  h²hh³Nh´Nubeh}”(h]”h ]”h"]”h$]”h&]”uh1j  h³hÇh´Khj  ubah}”(h]”h ]”h"]”h$]”h&]”uh1j  hhÿubj  )”}”(hŒ=Luis R. Rodriguez <mcgrof@do-not-panic.com> - April 9, 2015

”h]”j	  )”}”(hŒ;Luis R. Rodriguez <mcgrof@do-not-panic.com> - April 9, 2015”h]”(hŒLuis R. Rodriguez <”…””}”(hj7  h²hh³Nh´Nubj  )”}”(hŒmcgrof@do-not-panic.com”h]”hŒmcgrof@do-not-panic.com”…””}”(hj?  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”Œrefuri”Œmailto:mcgrof@do-not-panic.com”uh1j  hj7  ubhŒ> - April 9, 2015”…””}”(hj7  h²hh³Nh´Nubeh}”(h]”h ]”h"]”h$]”h&]”uh1j  h³hÇh´Khj3  ubah}”(h]”h ]”h"]”h$]”h&]”uh1j  hhÿubeh}”(h]”h ]”h"]”h$]”h&]”Œbullet”Œ-”uh1hýh³hÇh´Khhùubah}”(h]”h ]”h"]”h$]”h&]”uh1h÷hhäubeh}”(h]”h ]”h"]”h$]”h&]”uh1hâh³hÇh´Khhßh²hubah}”(h]”h ]”h"]”h$]”h&]”uh1hÝhhÊh²hh³hÇh´KubhÉ)”}”(hhh]”(hÎ)”}”(hŒPhasing out MTRR use”h]”hŒPhasing out MTRR use”…””}”(hj|  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÍhjy  h²hh³hÇh´Kubj	  )”}”(hX+  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.”h]”hX+  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.”…””}”(hjŠ  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j  h³hÇh´Khjy  h²hubj	  )”}”(hXC  Even if Linux does not use MTRRs directly, some x86 platform firmware may still
set up MTRRs early before booting the OS. They do this as some platform
firmware may still have implemented access to MTRRs which would be controlled
and handled by the platform firmware directly. An example of platform use of
MTRRs is through the use of SMI handlers, one case could be for fan control,
the platform code would need uncachable access to some of its fan control
registers. Such platform access does not need any Operating System MTRR code in
place other than mtrr_type_lookup() to ensure any OS specific mapping requests
are aligned with platform MTRR setup. If MTRRs are only set up by the platform
firmware code though and the OS does not make any specific MTRR mapping
requests mtrr_type_lookup() should always return MTRR_TYPE_INVALID.”h]”hXC  Even if Linux does not use MTRRs directly, some x86 platform firmware may still
set up MTRRs early before booting the OS. They do this as some platform
firmware may still have implemented access to MTRRs which would be controlled
and handled by the platform firmware directly. An example of platform use of
MTRRs is through the use of SMI handlers, one case could be for fan control,
the platform code would need uncachable access to some of its fan control
registers. Such platform access does not need any Operating System MTRR code in
place other than mtrr_type_lookup() to ensure any OS specific mapping requests
are aligned with platform MTRR setup. If MTRRs are only set up by the platform
firmware code though and the OS does not make any specific MTRR mapping
requests mtrr_type_lookup() should always return MTRR_TYPE_INVALID.”…””}”(hj˜  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j  h³hÇh´Khjy  h²hubj	  )”}”(hŒ4For details refer to Documentation/arch/x86/pat.rst.”h]”hŒ4For details refer to Documentation/arch/x86/pat.rst.”…””}”(hj¦  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j  h³hÇh´Khjy  h²hubhŒtip”“”)”}”(hX•  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.”h]”(j	  )”}”(hX¸  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.”h]”hX¸  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.”…””}”(hjº  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j  h³hÇh´K"hj¶  ubj	  )”}”(hŒ±The Cyrix 6x86, 6x86MX and M II processors have Address Range
Registers (ARRs) which provide a similar functionality to MTRRs. For
these, the ARRs are used to emulate the MTRRs.”h]”hŒ±The Cyrix 6x86, 6x86MX and M II processors have Address Range
Registers (ARRs) which provide a similar functionality to MTRRs. For
these, the ARRs are used to emulate the MTRRs.”…””}”(hjÈ  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j  h³hÇh´K*hj¶  ubj	  )”}”(hŒ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.”h]”hŒ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.”…””}”(hjÖ  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j  h³hÇh´K.hj¶  ubj	  )”}”(hŒSThe Centaur C6 (WinChip) has 8 MCRs, allowing write-combining. These
are supported.”h]”hŒSThe Centaur C6 (WinChip) has 8 MCRs, allowing write-combining. These
are supported.”…””}”(hjä  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j  h³hÇh´K2hj¶  ubj	  )”}”(hŒ<The VIA Cyrix III and VIA C3 CPUs offer 8 Intel style MTRRs.”h]”hŒ<The VIA Cyrix III and VIA C3 CPUs offer 8 Intel style MTRRs.”…””}”(hjò  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j  h³hÇh´K5hj¶  ubj	  )”}”(hX  The CONFIG_MTRR option creates a /proc/mtrr file which may be used
to manipulate your MTRRs. Typically the X server should use
this. This should have a reasonably generic interface so that
similar control registers on other processors can be easily
supported.”h]”hX  The CONFIG_MTRR option creates a /proc/mtrr file which may be used
to manipulate your MTRRs. Typically the X server should use
this. This should have a reasonably generic interface so that
similar control registers on other processors can be easily
supported.”…””}”(hj   h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j  h³hÇh´K7hj¶  ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j´  hjy  h²hh³hÇh´Nubj	  )”}”(hXA  There are two interfaces to /proc/mtrr: one is an ASCII interface
which allows you to read and write. The other is an ioctl()
interface. The ASCII interface is meant for administration. The
ioctl() interface is meant for C programs (i.e. the X server). The
interfaces are described below, with sample commands and C code.”h]”hXA  There are two interfaces to /proc/mtrr: one is an ASCII interface
which allows you to read and write. The other is an ioctl()
interface. The ASCII interface is meant for administration. The
ioctl() interface is meant for C programs (i.e. the X server). The
interfaces are described below, with sample commands and C code.”…””}”(hj  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j  h³hÇh´K=hjy  h²hubeh}”(h]”Œphasing-out-mtrr-use”ah ]”h"]”Œphasing out mtrr use”ah$]”h&]”uh1hÈhhÊh²hh³hÇh´KubhÉ)”}”(hhh]”(hÎ)”}”(hŒReading MTRRs from the shell”h]”hŒReading MTRRs from the shell”…””}”(hj-  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÍhj*  h²hh³hÇh´KEubhŒliteral_block”“”)”}”(hŒ”% cat /proc/mtrr
reg00: base=0x00000000 (   0MB), size= 128MB: write-back, count=1
reg01: base=0x08000000 ( 128MB), size=  64MB: write-back, count=1”h]”hŒ”% cat /proc/mtrr
reg00: base=0x00000000 (   0MB), size= 128MB: write-back, count=1
reg01: base=0x08000000 ( 128MB), size=  64MB: write-back, count=1”…””}”hj=  sbah}”(h]”h ]”h"]”h$]”h&]”hÅhÆuh1j;  h³hÇh´KHhj*  h²hubj	  )”}”(hŒ!Creating MTRRs from the C-shell::”h]”hŒ Creating MTRRs from the C-shell:”…””}”(hjK  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j  h³hÇh´KLhj*  h²hubj<  )”}”(hŒI# echo "base=0xf8000000 size=0x400000 type=write-combining" >! /proc/mtrr”h]”hŒI# echo "base=0xf8000000 size=0x400000 type=write-combining" >! /proc/mtrr”…””}”hjY  sbah}”(h]”h ]”h"]”h$]”h&]”hÅhÆuh1j;  h³hÇh´KNhj*  h²hubj	  )”}”(hŒor if you use bash::”h]”hŒor if you use bash:”…””}”(hjg  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j  h³hÇh´KPhj*  h²hubj<  )”}”(hŒI# echo "base=0xf8000000 size=0x400000 type=write-combining" >| /proc/mtrr”h]”hŒI# echo "base=0xf8000000 size=0x400000 type=write-combining" >| /proc/mtrr”…””}”hju  sbah}”(h]”h ]”h"]”h$]”h&]”hÅhÆuh1j;  h³hÇh´KRhj*  h²hubj	  )”}”(hŒAnd the result thereof::”h]”hŒAnd the result thereof:”…””}”(hjƒ  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j  h³hÇh´KThj*  h²hubj<  )”}”(hŒÛ% 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”h]”hŒÛ% 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”…””}”hj‘  sbah}”(h]”h ]”h"]”h$]”h&]”hÅhÆuh1j;  h³hÇh´KVhj*  h²hubj	  )”}”(hŒôThis is for video RAM at base address 0xf8000000 and size 4 megabytes. To
find out your base address, you need to look at the output of your X
server, which tells you where the linear framebuffer address is. A
typical line that you may get is::”h]”hŒóThis is for video RAM at base address 0xf8000000 and size 4 megabytes. To
find out your base address, you need to look at the output of your X
server, which tells you where the linear framebuffer address is. A
typical line that you may get is:”…””}”(hjŸ  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j  h³hÇh´K[hj*  h²hubj<  )”}”(hŒ/(--) S3: PCI: 968 rev 0, Linear FB @ 0xf8000000”h]”hŒ/(--) S3: PCI: 968 rev 0, Linear FB @ 0xf8000000”…””}”hj­  sbah}”(h]”h ]”h"]”h$]”h&]”hÅhÆuh1j;  h³hÇh´K`hj*  h²hubj	  )”}”(hŒ©Note that you should only use the value from the X server, as it may
move the framebuffer base address, so the only value you can trust is
that reported by the X server.”h]”hŒ©Note that you should only use the value from the X server, as it may
move the framebuffer base address, so the only value you can trust is
that reported by the X server.”…””}”(hj»  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j  h³hÇh´Kbhj*  h²hubj	  )”}”(hŒmTo find out the size of your framebuffer (what, you don't actually
know?), the following line will tell you::”h]”hŒnTo find out the size of your framebuffer (what, you donâ€™t actually
know?), the following line will tell you:”…””}”(hjÉ  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j  h³hÇh´Kfhj*  h²hubj<  )”}”(hŒ(--) S3: videoram:  4096k”h]”hŒ(--) S3: videoram:  4096k”…””}”hj×  sbah}”(h]”h ]”h"]”h$]”h&]”hÅhÆuh1j;  h³hÇh´Kihj*  h²hubj	  )”}”(hXH  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.”h]”hXL  Thatâ€™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 wonâ€™t have to do anything. If you use a
commercial X server, lobby your vendor to add support for MTRRs.”…””}”(hjå  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j  h³hÇh´Kkhj*  h²hubeh}”(h]”Œreading-mtrrs-from-the-shell”ah ]”h"]”Œreading mtrrs from the shell”ah$]”h&]”uh1hÈhhÊh²hh³hÇh´KEubhÉ)”}”(hhh]”(hÎ)”}”(hŒCreating overlapping MTRRs”h]”hŒCreating overlapping MTRRs”…””}”(hjþ  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÍhjû  h²hh³hÇh´Ksubj<  )”}”(hŒ‡%echo "base=0xfb000000 size=0x1000000 type=write-combining" >/proc/mtrr
%echo "base=0xfb000000 size=0x1000 type=uncachable" >/proc/mtrr”h]”hŒ‡%echo "base=0xfb000000 size=0x1000000 type=write-combining" >/proc/mtrr
%echo "base=0xfb000000 size=0x1000 type=uncachable" >/proc/mtrr”…””}”hj  sbah}”(h]”h ]”h"]”h$]”h&]”hÅhÆuh1j;  h³hÇh´Kvhjû  h²hubj	  )”}”(hŒAnd the results::”h]”hŒAnd the results:”…””}”(hj  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j  h³hÇh´Kyhjû  h²hubj<  )”}”(hŒÛ% cat /proc/mtrr
reg00: base=0x00000000 (   0MB), size=  64MB: write-back, count=1
reg01: base=0xfb000000 (4016MB), size=  16MB: write-combining, count=1
reg02: base=0xfb000000 (4016MB), size=   4kB: uncachable, count=1”h]”hŒÛ% cat /proc/mtrr
reg00: base=0x00000000 (   0MB), size=  64MB: write-back, count=1
reg01: base=0xfb000000 (4016MB), size=  16MB: write-combining, count=1
reg02: base=0xfb000000 (4016MB), size=   4kB: uncachable, count=1”…””}”hj(  sbah}”(h]”h ]”h"]”h$]”h&]”hÅhÆuh1j;  h³hÇh´K{hjû  h²hubj	  )”}”(hŒŽSome cards (especially Voodoo Graphics boards) need this 4 kB area
excluded from the beginning of the region because it is used for
registers.”h]”hŒŽSome cards (especially Voodoo Graphics boards) need this 4 kB area
excluded from the beginning of the region because it is used for
registers.”…””}”(hj6  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j  h³hÇh´K€hjû  h²hubj	  )”}”(hŒoNOTE: You can only create type=uncachable region, if the first
region that you created is type=write-combining.”h]”hŒoNOTE: You can only create type=uncachable region, if the first
region that you created is type=write-combining.”…””}”(hjD  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j  h³hÇh´K„hjû  h²hubeh}”(h]”Œcreating-overlapping-mtrrs”ah ]”h"]”Œcreating overlapping mtrrs”ah$]”h&]”uh1hÈhhÊh²hh³hÇh´KsubhÉ)”}”(hhh]”(hÎ)”}”(hŒRemoving MTRRs from the C-shel”h]”hŒRemoving MTRRs from the C-shel”…””}”(hj]  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÍhjZ  h²hh³hÇh´K‰ubj<  )”}”(hŒ % echo "disable=2" >! /proc/mtrr”h]”hŒ % echo "disable=2" >! /proc/mtrr”…””}”hjk  sbah}”(h]”h ]”h"]”h$]”h&]”hÅhÆuh1j;  h³hÇh´KŒhjZ  h²hubj	  )”}”(hŒor using bash::”h]”hŒor using bash:”…””}”(hjy  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j  h³hÇh´KŽhjZ  h²hubj<  )”}”(hŒ % echo "disable=2" >| /proc/mtrr”h]”hŒ % echo "disable=2" >| /proc/mtrr”…””}”hj‡  sbah}”(h]”h ]”h"]”h$]”h&]”hÅhÆuh1j;  h³hÇh´KhjZ  h²hubeh}”(h]”Œremoving-mtrrs-from-the-c-shel”ah ]”h"]”Œremoving mtrrs from the c-shel”ah$]”h&]”uh1hÈhhÊh²hh³hÇh´K‰ubhÉ)”}”(hhh]”(hÎ)”}”(hŒ.Reading MTRRs from a C program using ioctl()'s”h]”hŒ0Reading MTRRs from a C program using ioctl()â€™s”…””}”(hj   h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÍhj  h²hh³hÇh´K”ubj<  )”}”(hXš
  /*  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  */”h]”hXš
  /*  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  */”…””}”hj®  sbah}”(h]”h ]”h"]”h$]”h&]”hÅhÆuh1j;  h³hÇh´K—hj  h²hubeh}”(h]”Œ,reading-mtrrs-from-a-c-program-using-ioctl-s”ah ]”h"]”Œ.reading mtrrs from a c program using ioctl()'s”ah$]”h&]”uh1hÈhhÊh²hh³hÇh´K”ubhÉ)”}”(hhh]”(hÎ)”}”(hŒ1Creating MTRRs from a C programme using ioctl()'s”h]”hŒ3Creating MTRRs from a C programme using ioctl()â€™s”…””}”(hjÇ  h²hh³Nh´Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÍhjÄ  h²hh³hÇh´K÷ubj<  )”}”(hX  /*  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  */”h]”hX  /*  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  */”…””}”hjÕ  sbah}”(h]”h ]”h"]”h$]”h&]”hÅhÆuh1j;  h³hÇh´KúhjÄ  h²hubeh}”(h]”Œ/creating-mtrrs-from-a-c-programme-using-ioctl-s”ah ]”h"]”Œ1creating mtrrs from a c programme using ioctl()'s”ah$]”h&]”uh1hÈhhÊh²hh³hÇh´K÷ubeh}”(h]”Œ'mtrr-memory-type-range-register-control”ah ]”h"]”Œ)mtrr (memory type range register) control”ah$]”h&]”uh1hÈhhh²hh³hÇh´Kubeh}”(h]”h ]”h"]”h$]”h&]”Œsource”hÇuh1hŒcurrent_source”NŒcurrent_line”NŒsettings”Œdocutils.frontend”ŒValues”“”)”}”(hÍNŒ	generator”NŒ	datestamp”NŒsource_link”NŒ
source_url”NŒtoc_backlinks”Œentry”Œfootnote_backlinks”KŒsectnum_xform”KŒstrip_comments”NŒstrip_elements_with_classes”NŒstrip_classes”NŒreport_level”KŒ
halt_level”KŒexit_status_level”KŒdebug”NŒwarning_stream”NŒ	traceback”ˆŒinput_encoding”Œ	utf-8-sig”Œinput_encoding_error_handler”Œstrict”Œoutput_encoding”Œutf-8”Œoutput_encoding_error_handler”j  Œerror_encoding”Œutf-8”Œerror_encoding_error_handler”Œbackslashreplace”Œlanguage_code”Œen”Œrecord_dependencies”NŒconfig”NŒ	id_prefix”hŒauto_id_prefix”Œid”Œdump_settings”NŒdump_internals”NŒdump_transforms”NŒdump_pseudo_xml”NŒexpose_internals”NŒstrict_visitor”NŒ_disable_config”NŒ_source”hÇŒ_destination”NŒ_config_files”]”Œ7/var/lib/git/docbuild/linux/Documentation/docutils.conf”aŒfile_insertion_enabled”ˆŒraw_enabled”KŒline_length_limit”M'Œpep_references”NŒpep_base_url”Œhttps://peps.python.org/”Œpep_file_url_template”Œpep-%04d”Œrfc_references”NŒrfc_base_url”Œ&https://datatracker.ietf.org/doc/html/”Œ	tab_width”KŒtrim_footnote_reference_space”‰Œsyntax_highlight”Œlong”Œsmart_quotes”ˆŒsmartquotes_locales”]”Œcharacter_level_inline_markup”‰Œdoctitle_xform”‰Œdocinfo_xform”KŒsectsubtitle_xform”‰Œimage_loading”Œlink”Œembed_stylesheet”‰Œcloak_email_addresses”ˆŒsection_self_link”‰Œenv”NubŒreporter”NŒindirect_targets”]”Œsubstitution_defs”}”Œsubstitution_names”}”Œrefnames”}”Œrefids”}”Œnameids”}”(jð  jí  j'  j$  jø  jõ  jW  jT  jš  j—  jÁ  j¾  jè  jå  uŒ	nametypes”}”(jð  ‰j'  ‰jø  ‰jW  ‰jš  ‰jÁ  ‰jè  ‰uh}”(jí  hÊj$  jy  jõ  j*  jT  jû  j—  jZ  j¾  j  jå  jÄ  uŒfootnote_refs”}”Œcitation_refs”}”Œautofootnotes”]”Œautofootnote_refs”]”Œsymbol_footnotes”]”Œsymbol_footnote_refs”]”Œ	footnotes”]”Œ	citations”]”Œautofootnote_start”KŒsymbol_footnote_start”K Œ
id_counter”Œcollections”ŒCounter”“”}”…”R”Œparse_messages”]”Œtransform_messages”]”Œtransformer”NŒinclude_log”]”Œ
decoration”Nh²hub.