sphinx.addnodesdocument)}( rawsource children]( translations
LanguagesNode)}(hhh](h pending_xref)}(hhh]docutils.nodesTextChinese (Simplified)}parenthsba
attributes}(ids]classes]names]dupnames]backrefs] refdomainstdreftypedoc reftarget'/translations/zh_CN/filesystems/debugfsmodnameN classnameN refexplicitutagnamehhh ubh)}(hhh]hChinese (Traditional)}hh2sbah }(h ]h ]h"]h$]h&] refdomainh)reftypeh+ reftarget'/translations/zh_TW/filesystems/debugfsmodnameN classnameN refexplicituh1hhh ubh)}(hhh]hItalian}hhFsbah }(h ]h ]h"]h$]h&] refdomainh)reftypeh+ reftarget'/translations/it_IT/filesystems/debugfsmodnameN classnameN refexplicituh1hhh ubh)}(hhh]hJapanese}hhZsbah }(h ]h ]h"]h$]h&] refdomainh)reftypeh+ reftarget'/translations/ja_JP/filesystems/debugfsmodnameN classnameN refexplicituh1hhh ubh)}(hhh]hKorean}hhnsbah }(h ]h ]h"]h$]h&] refdomainh)reftypeh+ reftarget'/translations/ko_KR/filesystems/debugfsmodnameN classnameN refexplicituh1hhh ubh)}(hhh]hPortuguese (Brazilian)}hhsbah }(h ]h ]h"]h$]h&] refdomainh)reftypeh+ reftarget'/translations/pt_BR/filesystems/debugfsmodnameN classnameN refexplicituh1hhh ubh)}(hhh]hSpanish}hhsbah }(h ]h ]h"]h$]h&] refdomainh)reftypeh+ reftarget'/translations/sp_SP/filesystems/debugfsmodnameN classnameN refexplicituh1hhh ubeh }(h ]h ]h"]h$]h&]current_languageEnglishuh1h
hh _documenthsourceNlineNubhcomment)}(h SPDX-License-Identifier: GPL-2.0h]h SPDX-License-Identifier: GPL-2.0}hhsbah }(h ]h ]h"]h$]h&] xml:spacepreserveuh1hhhhhhA/var/lib/git/docbuild/linux/Documentation/filesystems/debugfs.rsthKubh)}(h4This data file has been placed in the public domain.h]h4This data file has been placed in the public domain.}hhsbah }(h ]h ]h"]h$]h&]hhuh1hhhhhho/srv/docbuild/lib/venvs/build-kernel-docs/lib64/python3.9/site-packages/docutils/parsers/rst/include/isonum.txthKubh)}(hDerived from the Unicode character mappings available from
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Processed by unicode2rstsubs.py, part of Docutils:
.h]hDerived from the Unicode character mappings available from
.
Processed by unicode2rstsubs.py, part of Docutils:
.}hhsbah }(h ]h ]h"]h$]h&]hhuh1hhhhhhhhKubhsubstitution_definition)}(h*.. |amp| unicode:: U+00026 .. AMPERSANDh]h&}hhsbah }(h ]h ]h"]ampah$]h&]uh1hhhhKhhhhubh)}(h+.. |apos| unicode:: U+00027 .. APOSTROPHEh]h'}hhsbah }(h ]h ]h"]aposah$]h&]uh1hhhhKhhhhubh)}(h).. |ast| unicode:: U+0002A .. ASTERISKh]h*}hj sbah }(h ]h ]h"]astah$]h&]uh1hhhhK hhhhubh)}(h+.. |brvbar| unicode:: U+000A6 .. BROKEN BARh]h¦}hj sbah }(h ]h ]h"]brvbarah$]h&]uh1hhhhK
hhhhubh)}(h0.. |bsol| unicode:: U+0005C .. REVERSE SOLIDUSh]h\}hj# sbah }(h ]h ]h"]bsolah$]h&]uh1hhhhK hhhhubh)}(h*.. |cent| unicode:: U+000A2 .. CENT SIGNh]h¢}hj2 sbah }(h ]h ]h"]centah$]h&]uh1hhhhK hhhhubh)}(h&.. |colon| unicode:: U+0003A .. COLONh]h:}hjA sbah }(h ]h ]h"]colonah$]h&]uh1hhhhK
hhhhubh)}(h&.. |comma| unicode:: U+0002C .. COMMAh]h,}hjP sbah }(h ]h ]h"]commaah$]h&]uh1hhhhKhhhhubh)}(h... |commat| unicode:: U+00040 .. COMMERCIAL ATh]h@}hj_ sbah }(h ]h ]h"]commatah$]h&]uh1hhhhKhhhhubh)}(h/.. |copy| unicode:: U+000A9 .. COPYRIGHT SIGNh]h©}hjn sbah }(h ]h ]h"]copyah$]h&]uh1hhhhKhhhhubh)}(h... |curren| unicode:: U+000A4 .. CURRENCY SIGNh]h¤}hj} sbah }(h ]h ]h"]currenah$]h&]uh1hhhhKhhhhubh)}(h0.. |darr| unicode:: U+02193 .. DOWNWARDS ARROWh]h↓}hj sbah }(h ]h ]h"]darrah$]h&]uh1hhhhKhhhhubh)}(h,.. |deg| unicode:: U+000B0 .. DEGREE SIGNh]h°}hj sbah }(h ]h ]h"]degah$]h&]uh1hhhhKhhhhubh)}(h... |divide| unicode:: U+000F7 .. DIVISION SIGNh]h÷}hj sbah }(h ]h ]h"]divideah$]h&]uh1hhhhKhhhhubh)}(h,.. |dollar| unicode:: U+00024 .. DOLLAR SIGNh]h$}hj sbah }(h ]h ]h"]dollarah$]h&]uh1hhhhKhhhhubh)}(h,.. |equals| unicode:: U+0003D .. EQUALS SIGNh]h=}hj sbah }(h ]h ]h"]equalsah$]h&]uh1hhhhKhhhhubh)}(h1.. |excl| unicode:: U+00021 .. EXCLAMATION MARKh]h!}hj sbah }(h ]h ]h"]exclah$]h&]uh1hhhhKhhhhubh)}(h9.. |frac12| unicode:: U+000BD .. VULGAR FRACTION ONE HALFh]h½}hj sbah }(h ]h ]h"]frac12ah$]h&]uh1hhhhKhhhhubh)}(h<.. |frac14| unicode:: U+000BC .. VULGAR FRACTION ONE QUARTERh]h¼}hj sbah }(h ]h ]h"]frac14ah$]h&]uh1hhhhKhhhhubh)}(h;.. |frac18| unicode:: U+0215B .. VULGAR FRACTION ONE EIGHTHh]h⅛}hj sbah }(h ]h ]h"]frac18ah$]h&]uh1hhhhKhhhhubh)}(h?.. |frac34| unicode:: U+000BE .. VULGAR FRACTION THREE QUARTERSh]h¾}hj sbah }(h ]h ]h"]frac34ah$]h&]uh1hhhhKhhhhubh)}(h>.. |frac38| unicode:: U+0215C .. VULGAR FRACTION THREE EIGHTHSh]h⅜}hj" sbah }(h ]h ]h"]frac38ah$]h&]uh1hhhhK hhhhubh)}(h=.. |frac58| unicode:: U+0215D .. VULGAR FRACTION FIVE EIGHTHSh]h⅝}hj1 sbah }(h ]h ]h"]frac58ah$]h&]uh1hhhhK hhhhubh)}(h>.. |frac78| unicode:: U+0215E .. VULGAR FRACTION SEVEN EIGHTHSh]h⅞}hj@ sbah }(h ]h ]h"]frac78ah$]h&]uh1hhhhK hhhhubh)}(h2.. |gt| unicode:: U+0003E .. GREATER-THAN SIGNh]h>}hjO sbah }(h ]h ]h"]gtah$]h&]uh1hhhhK hhhhubh)}(h9.. |half| unicode:: U+000BD .. VULGAR FRACTION ONE HALFh]h½}hj^ sbah }(h ]h ]h"]halfah$]h&]uh1hhhhK hhhhubh)}(h/.. |horbar| unicode:: U+02015 .. HORIZONTAL BARh]h―}hjm sbah }(h ]h ]h"]horbarah$]h&]uh1hhhhK!hhhhubh)}(h'.. |hyphen| unicode:: U+02010 .. HYPHENh]h‐}hj| sbah }(h ]h ]h"]hyphenah$]h&]uh1hhhhK"hhhhubh)}(h:.. |iexcl| unicode:: U+000A1 .. INVERTED EXCLAMATION MARKh]h¡}hj sbah }(h ]h ]h"]iexclah$]h&]uh1hhhhK#hhhhubh)}(h7.. |iquest| unicode:: U+000BF .. INVERTED QUESTION MARKh]h¿}hj sbah }(h ]h ]h"]iquestah$]h&]uh1hhhhK$hhhhubh)}(hJ.. |laquo| unicode:: U+000AB .. LEFT-POINTING DOUBLE ANGLE QUOTATION MARKh]h«}hj sbah }(h ]h ]h"]laquoah$]h&]uh1hhhhK%hhhhubh)}(h0.. |larr| unicode:: U+02190 .. LEFTWARDS ARROWh]h←}hj sbah }(h ]h ]h"]larrah$]h&]uh1hhhhK&hhhhubh)}(h3.. |lcub| unicode:: U+0007B .. LEFT CURLY BRACKETh]h{}hj sbah }(h ]h ]h"]lcubah$]h&]uh1hhhhK'hhhhubh)}(h;.. |ldquo| unicode:: U+0201C .. LEFT DOUBLE QUOTATION MARKh]h“}hj sbah }(h ]h ]h"]ldquoah$]h&]uh1hhhhK(hhhhubh)}(h).. |lowbar| unicode:: U+0005F .. LOW LINEh]h_}hj sbah }(h ]h ]h"]lowbarah$]h&]uh1hhhhK)hhhhubh)}(h1.. |lpar| unicode:: U+00028 .. LEFT PARENTHESISh]h(}hj sbah }(h ]h ]h"]lparah$]h&]uh1hhhhK*hhhhubh)}(h4.. |lsqb| unicode:: U+0005B .. LEFT SQUARE BRACKETh]h[}hj sbah }(h ]h ]h"]lsqbah$]h&]uh1hhhhK+hhhhubh)}(h;.. |lsquo| unicode:: U+02018 .. LEFT SINGLE QUOTATION MARKh]h‘}hj sbah }(h ]h ]h"]lsquoah$]h&]uh1hhhhK,hhhhubh)}(h/.. |lt| unicode:: U+0003C .. LESS-THAN SIGNh]h<}hj! sbah }(h ]h ]h"]ltah$]h&]uh1hhhhK-hhhhubh)}(h+.. |micro| unicode:: U+000B5 .. MICRO SIGNh]hµ}hj0 sbah }(h ]h ]h"]microah$]h&]uh1hhhhK.hhhhubh)}(h+.. |middot| unicode:: U+000B7 .. MIDDLE DOTh]h·}hj? sbah }(h ]h ]h"]middotah$]h&]uh1hhhhK/hhhhubh)}(h/.. |nbsp| unicode:: U+000A0 .. NO-BREAK SPACEh]h }hjN sbah }(h ]h ]h"]nbspah$]h&]uh1hhhhK0hhhhubh)}(h).. |not| unicode:: U+000AC .. NOT SIGNh]h¬}hj] sbah }(h ]h ]h"]notah$]h&]uh1hhhhK1hhhhubh)}(h,.. |num| unicode:: U+00023 .. NUMBER SIGNh]h#}hjl sbah }(h ]h ]h"]numah$]h&]uh1hhhhK2hhhhubh)}(h).. |ohm| unicode:: U+02126 .. OHM SIGNh]hΩ}hj{ sbah }(h ]h ]h"]ohmah$]h&]uh1hhhhK3hhhhubh)}(h;.. |ordf| unicode:: U+000AA .. FEMININE ORDINAL INDICATORh]hª}hj sbah }(h ]h ]h"]ordfah$]h&]uh1hhhhK4hhhhubh)}(h<.. |ordm| unicode:: U+000BA .. MASCULINE ORDINAL INDICATORh]hº}hj sbah }(h ]h ]h"]ordmah$]h&]uh1hhhhK5hhhhubh)}(h-.. |para| unicode:: U+000B6 .. PILCROW SIGNh]h¶}hj sbah }(h ]h ]h"]paraah$]h&]uh1hhhhK6hhhhubh)}(h-.. |percnt| unicode:: U+00025 .. PERCENT SIGNh]h%}hj sbah }(h ]h ]h"]percntah$]h&]uh1hhhhK7hhhhubh)}(h*.. |period| unicode:: U+0002E .. FULL STOPh]h.}hj sbah }(h ]h ]h"]periodah$]h&]uh1hhhhK8hhhhubh)}(h*.. |plus| unicode:: U+0002B .. PLUS SIGNh]h+}hj sbah }(h ]h ]h"]plusah$]h&]uh1hhhhK9hhhhubh)}(h0.. |plusmn| unicode:: U+000B1 .. PLUS-MINUS SIGNh]h±}hj sbah }(h ]h ]h"]plusmnah$]h&]uh1hhhhK:hhhhubh)}(h+.. |pound| unicode:: U+000A3 .. POUND SIGNh]h£}hj sbah }(h ]h ]h"]poundah$]h&]uh1hhhhK;hhhhubh)}(h... |quest| unicode:: U+0003F .. QUESTION MARKh]h?}hj sbah }(h ]h ]h"]questah$]h&]uh1hhhhKhhhhubh)}(h1.. |rarr| unicode:: U+02192 .. RIGHTWARDS ARROWh]h→}hj/ sbah }(h ]h ]h"]rarrah$]h&]uh1hhhhK?hhhhubh)}(h4.. |rcub| unicode:: U+0007D .. RIGHT CURLY BRACKETh]h}}hj> sbah }(h ]h ]h"]rcubah$]h&]uh1hhhhK@hhhhubh)}(h<.. |rdquo| unicode:: U+0201D .. RIGHT DOUBLE QUOTATION MARKh]h”}hjM sbah }(h ]h ]h"]rdquoah$]h&]uh1hhhhKAhhhhubh)}(h0.. |reg| unicode:: U+000AE .. REGISTERED SIGNh]h®}hj\ sbah }(h ]h ]h"]regah$]h&]uh1hhhhKBhhhhubh)}(h2.. |rpar| unicode:: U+00029 .. RIGHT PARENTHESISh]h)}hjk sbah }(h ]h ]h"]rparah$]h&]uh1hhhhKChhhhubh)}(h5.. |rsqb| unicode:: U+0005D .. RIGHT SQUARE BRACKETh]h]}hjz sbah }(h ]h ]h"]rsqbah$]h&]uh1hhhhKDhhhhubh)}(h<.. |rsquo| unicode:: U+02019 .. RIGHT SINGLE QUOTATION MARKh]h’}hj sbah }(h ]h ]h"]rsquoah$]h&]uh1hhhhKEhhhhubh)}(h-.. |sect| unicode:: U+000A7 .. SECTION SIGNh]h§}hj sbah }(h ]h ]h"]sectah$]h&]uh1hhhhKFhhhhubh)}(h*.. |semi| unicode:: U+0003B .. SEMICOLONh]h;}hj sbah }(h ]h ]h"]semiah$]h&]uh1hhhhKGhhhhubh)}(h,.. |shy| unicode:: U+000AD .. SOFT HYPHENh]h}hj sbah }(h ]h ]h"]shyah$]h&]uh1hhhhKHhhhhubh)}(h(.. |sol| unicode:: U+0002F .. SOLIDUSh]h/}hj sbah }(h ]h ]h"]solah$]h&]uh1hhhhKIhhhhubh)}(h,.. |sung| unicode:: U+0266A .. EIGHTH NOTEh]h♪}hj sbah }(h ]h ]h"]sungah$]h&]uh1hhhhKJhhhhubh)}(h0.. |sup1| unicode:: U+000B9 .. SUPERSCRIPT ONEh]h¹}hj sbah }(h ]h ]h"]sup1ah$]h&]uh1hhhhKKhhhhubh)}(h0.. |sup2| unicode:: U+000B2 .. SUPERSCRIPT TWOh]h²}hj sbah }(h ]h ]h"]sup2ah$]h&]uh1hhhhKLhhhhubh)}(h2.. |sup3| unicode:: U+000B3 .. SUPERSCRIPT THREEh]h³}hj sbah }(h ]h ]h"]sup3ah$]h&]uh1hhhhKMhhhhubh)}(h4.. |times| unicode:: U+000D7 .. MULTIPLICATION SIGNh]h×}hj sbah }(h ]h ]h"]timesah$]h&]uh1hhhhKNhhhhubh)}(h0.. |trade| unicode:: U+02122 .. TRADE MARK SIGNh]h™}hj sbah }(h ]h ]h"]tradeah$]h&]uh1hhhhKOhhhhubh)}(h... |uarr| unicode:: U+02191 .. UPWARDS ARROWh]h↑}hj. sbah }(h ]h ]h"]uarrah$]h&]uh1hhhhKPhhhhubh)}(h... |verbar| unicode:: U+0007C .. VERTICAL LINEh]h|}hj= sbah }(h ]h ]h"]verbarah$]h&]uh1hhhhKQhhhhubh)}(h*.. |yen| unicode:: U+000A5 .. YEN SIGN
h]h¥}hjL sbah }(h ]h ]h"]yenah$]h&]uh1hhhhKRhhhhubhsection)}(hhh](htitle)}(hDebugFSh]hDebugFS}(hjb hhhNhNubah }(h ]h ]h"]h$]h&]uh1j` hj] hhhhhKubh paragraph)}(h6Copyright |copy| 2009 Jonathan Corbet h](h
Copyright }(hjr hhhNhNubh©}(hjr hhhNhNubh 2009 Jonathan Corbet <}(hjr hhhNhNubh reference)}(hcorbet@lwn.neth]hcorbet@lwn.net}(hj hhhNhNubah }(h ]h ]h"]h$]h&]refurimailto:corbet@lwn.netuh1j hjr ubh>}(hjr hhhNhNubeh }(h ]h ]h"]h$]h&]uh1jp hhhKhj] hhubjq )}(hXk Debugfs exists as a simple way for kernel developers to make information
available to user space. Unlike /proc, which is only meant for information
about a process, or sysfs, which has strict one-value-per-file rules,
debugfs has no rules at all. Developers can put any information they want
there. The debugfs filesystem is also intended to not serve as a stable
ABI to user space; in theory, there are no stability constraints placed on
files exported there. The real world is not always so simple, though [1]_;
even debugfs interfaces are best designed with the idea that they will need
to be maintained forever.h](hX Debugfs exists as a simple way for kernel developers to make information
available to user space. Unlike /proc, which is only meant for information
about a process, or sysfs, which has strict one-value-per-file rules,
debugfs has no rules at all. Developers can put any information they want
there. The debugfs filesystem is also intended to not serve as a stable
ABI to user space; in theory, there are no stability constraints placed on
files exported there. The real world is not always so simple, though }(hj hhhNhNubhfootnote_reference)}(h[1]_h]h1}(hj hhhNhNubah }(h ]id1ah ]h"]h$]h&]refidid2docnamefilesystems/debugfsuh1j hj resolvedKubhg;
even debugfs interfaces are best designed with the idea that they will need
to be maintained forever.}(hj hhhNhNubeh }(h ]h ]h"]h$]h&]uh1jp hhhK
hj] hhubjq )}(h2Debugfs is typically mounted with a command like::h]h1Debugfs is typically mounted with a command like:}(hj hhhNhNubah }(h ]h ]h"]h$]h&]uh1jp hhhKhj] hhubh
literal_block)}(h'mount -t debugfs none /sys/kernel/debugh]h'mount -t debugfs none /sys/kernel/debug}hj sbah }(h ]h ]h"]h$]h&]hhuh1j hhhKhj] hhubjq )}(h(Or an equivalent /etc/fstab line).
The debugfs root directory is accessible only to the root user by
default. To change access to the tree the "uid", "gid" and "mode" mount
options can be used.h]h(Or an equivalent /etc/fstab line).
The debugfs root directory is accessible only to the root user by
default. To change access to the tree the “uid”, “gid” and “mode” mount
options can be used.}(hj hhhNhNubah }(h ]h ]h"]h$]h&]uh1jp hhhKhj] hhubjq )}(h:Note that the debugfs API is exported GPL-only to modules.h]h:Note that the debugfs API is exported GPL-only to modules.}(hj hhhNhNubah }(h ]h ]h"]h$]h&]uh1jp hhhK hj] hhubjq )}(hCode using debugfs should include . Then, the first order
of business will be to create at least one directory to hold a set of
debugfs files::h]hCode using debugfs should include . Then, the first order
of business will be to create at least one directory to hold a set of
debugfs files:}(hj hhhNhNubah }(h ]h ]h"]h$]h&]uh1jp hhhK hj] hhubj )}(hKstruct dentry *debugfs_create_dir(const char *name, struct dentry *parent);h]hKstruct dentry *debugfs_create_dir(const char *name, struct dentry *parent);}hj sbah }(h ]h ]h"]h$]h&]hhuh1j hhhK#hj] hhubjq )}(hX$ This call, if successful, will make a directory called name underneath the
indicated parent directory. If parent is NULL, the directory will be
created in the debugfs root. On success, the return value is a struct
dentry pointer which can be used to create files in the directory (and to
clean it up at the end). An ERR_PTR(-ERROR) return value indicates that
something went wrong. If ERR_PTR(-ENODEV) is returned, that is an
indication that the kernel has been built without debugfs support and none
of the functions described below will work.h]hX$ This call, if successful, will make a directory called name underneath the
indicated parent directory. If parent is NULL, the directory will be
created in the debugfs root. On success, the return value is a struct
dentry pointer which can be used to create files in the directory (and to
clean it up at the end). An ERR_PTR(-ERROR) return value indicates that
something went wrong. If ERR_PTR(-ENODEV) is returned, that is an
indication that the kernel has been built without debugfs support and none
of the functions described below will work.}(hj hhhNhNubah }(h ]h ]h"]h$]h&]uh1jp hhhK%hj] hhubjq )}(hJThe most general way to create a file within a debugfs directory is with::h]hIThe most general way to create a file within a debugfs directory is with:}(hj* hhhNhNubah }(h ]h ]h"]h$]h&]uh1jp hhhK.hj] hhubj )}(hstruct dentry *debugfs_create_file(const char *name, umode_t mode,
struct dentry *parent, void *data,
const struct file_operations *fops);h]hstruct dentry *debugfs_create_file(const char *name, umode_t mode,
struct dentry *parent, void *data,
const struct file_operations *fops);}hj8 sbah }(h ]h ]h"]h$]h&]hhuh1j hhhK0hj] hhubjq )}(hX9 Here, name is the name of the file to create, mode describes the access
permissions the file should have, parent indicates the directory which
should hold the file, data will be stored in the i_private field of the
resulting inode structure, and fops is a set of file operations which
implement the file's behavior. At a minimum, the read() and/or write()
operations should be provided; others can be included as needed. Again,
the return value will be a dentry pointer to the created file,
ERR_PTR(-ERROR) on error, or ERR_PTR(-ENODEV) if debugfs support is
missing.h]hX; Here, name is the name of the file to create, mode describes the access
permissions the file should have, parent indicates the directory which
should hold the file, data will be stored in the i_private field of the
resulting inode structure, and fops is a set of file operations which
implement the file’s behavior. At a minimum, the read() and/or write()
operations should be provided; others can be included as needed. Again,
the return value will be a dentry pointer to the created file,
ERR_PTR(-ERROR) on error, or ERR_PTR(-ENODEV) if debugfs support is
missing.}(hjF hhhNhNubah }(h ]h ]h"]h$]h&]uh1jp hhhK4hj] hhubjq )}(hPCreate a file with an initial size, the following function can be used
instead::h]hOCreate a file with an initial size, the following function can be used
instead:}(hjT hhhNhNubah }(h ]h ]h"]h$]h&]uh1jp hhhK>hj] hhubj )}(hvoid debugfs_create_file_size(const char *name, umode_t mode,
struct dentry *parent, void *data,
const struct file_operations *fops,
loff_t file_size);h]hvoid debugfs_create_file_size(const char *name, umode_t mode,
struct dentry *parent, void *data,
const struct file_operations *fops,
loff_t file_size);}hjb sbah }(h ]h ]h"]h$]h&]hhuh1j hhhKAhj] hhubjq )}(hjfile_size is the initial file size. The other parameters are the same
as the function debugfs_create_file.h]hjfile_size is the initial file size. The other parameters are the same
as the function debugfs_create_file.}(hjp hhhNhNubah }(h ]h ]h"]h$]h&]uh1jp hhhKFhj] hhubjq )}(hIn a number of cases, the creation of a set of file operations is not
actually necessary; the debugfs code provides a number of helper functions
for simple situations. Files containing a single integer value can be
created with any of::h]hIn a number of cases, the creation of a set of file operations is not
actually necessary; the debugfs code provides a number of helper functions
for simple situations. Files containing a single integer value can be
created with any of:}(hj~ hhhNhNubah }(h ]h ]h"]h$]h&]uh1jp hhhKIhj] hhubj )}(hX void debugfs_create_u8(const char *name, umode_t mode,
struct dentry *parent, u8 *value);
void debugfs_create_u16(const char *name, umode_t mode,
struct dentry *parent, u16 *value);
void debugfs_create_u32(const char *name, umode_t mode,
struct dentry *parent, u32 *value);
void debugfs_create_u64(const char *name, umode_t mode,
struct dentry *parent, u64 *value);h]hX void debugfs_create_u8(const char *name, umode_t mode,
struct dentry *parent, u8 *value);
void debugfs_create_u16(const char *name, umode_t mode,
struct dentry *parent, u16 *value);
void debugfs_create_u32(const char *name, umode_t mode,
struct dentry *parent, u32 *value);
void debugfs_create_u64(const char *name, umode_t mode,
struct dentry *parent, u64 *value);}hj sbah }(h ]h ]h"]h$]h&]hhuh1j hhhKNhj] hhubjq )}(hX
These files support both reading and writing the given value; if a specific
file should not be written to, simply set the mode bits accordingly. The
values in these files are in decimal; if hexadecimal is more appropriate,
the following functions can be used instead::h]hX These files support both reading and writing the given value; if a specific
file should not be written to, simply set the mode bits accordingly. The
values in these files are in decimal; if hexadecimal is more appropriate,
the following functions can be used instead:}(hj hhhNhNubah }(h ]h ]h"]h$]h&]uh1jp hhhKWhj] hhubj )}(hX void debugfs_create_x8(const char *name, umode_t mode,
struct dentry *parent, u8 *value);
void debugfs_create_x16(const char *name, umode_t mode,
struct dentry *parent, u16 *value);
void debugfs_create_x32(const char *name, umode_t mode,
struct dentry *parent, u32 *value);
void debugfs_create_x64(const char *name, umode_t mode,
struct dentry *parent, u64 *value);h]hX void debugfs_create_x8(const char *name, umode_t mode,
struct dentry *parent, u8 *value);
void debugfs_create_x16(const char *name, umode_t mode,
struct dentry *parent, u16 *value);
void debugfs_create_x32(const char *name, umode_t mode,
struct dentry *parent, u32 *value);
void debugfs_create_x64(const char *name, umode_t mode,
struct dentry *parent, u64 *value);}hj sbah }(h ]h ]h"]h$]h&]hhuh1j hhhK\hj] hhubjq )}(hX
These functions are useful as long as the developer knows the size of the
value to be exported. Some types can have different widths on different
architectures, though, complicating the situation somewhat. There are
functions meant to help out in such special cases::h]hX These functions are useful as long as the developer knows the size of the
value to be exported. Some types can have different widths on different
architectures, though, complicating the situation somewhat. There are
functions meant to help out in such special cases:}(hj hhhNhNubah }(h ]h ]h"]h$]h&]uh1jp hhhKehj] hhubj )}(h|void debugfs_create_size_t(const char *name, umode_t mode,
struct dentry *parent, size_t *value);h]h|void debugfs_create_size_t(const char *name, umode_t mode,
struct dentry *parent, size_t *value);}hj sbah }(h ]h ]h"]h$]h&]hhuh1j hhhKjhj] hhubjq )}(hfAs might be expected, this function will create a debugfs file to represent
a variable of type size_t.h]hfAs might be expected, this function will create a debugfs file to represent
a variable of type size_t.}(hj hhhNhNubah }(h ]h ]h"]h$]h&]uh1jp hhhKmhj] hhubjq )}(h^Similarly, there are helpers for variables of type unsigned long, in decimal
and hexadecimal::h]h]Similarly, there are helpers for variables of type unsigned long, in decimal
and hexadecimal:}(hj hhhNhNubah }(h ]h ]h"]h$]h&]uh1jp hhhKphj] hhubj )}(hX7 struct dentry *debugfs_create_ulong(const char *name, umode_t mode,
struct dentry *parent,
unsigned long *value);
void debugfs_create_xul(const char *name, umode_t mode,
struct dentry *parent, unsigned long *value);h]hX7 struct dentry *debugfs_create_ulong(const char *name, umode_t mode,
struct dentry *parent,
unsigned long *value);
void debugfs_create_xul(const char *name, umode_t mode,
struct dentry *parent, unsigned long *value);}hj sbah }(h ]h ]h"]h$]h&]hhuh1j hhhKshj] hhubjq )}(h.Boolean values can be placed in debugfs with::h]h-Boolean values can be placed in debugfs with:}(hj hhhNhNubah }(h ]h ]h"]h$]h&]uh1jp hhhKyhj] hhubj )}(hvvoid debugfs_create_bool(const char *name, umode_t mode,
struct dentry *parent, bool *value);h]hvvoid debugfs_create_bool(const char *name, umode_t mode,
struct dentry *parent, bool *value);}hj
sbah }(h ]h ]h"]h$]h&]hhuh1j hhhK{hj] hhubjq )}(hA read on the resulting file will yield either Y (for non-zero values) or
N, followed by a newline. If written to, it will accept either upper- or
lower-case values, or 1 or 0. Any other input will be silently ignored.h]hA read on the resulting file will yield either Y (for non-zero values) or
N, followed by a newline. If written to, it will accept either upper- or
lower-case values, or 1 or 0. Any other input will be silently ignored.}(hj hhhNhNubah }(h ]h ]h"]h$]h&]uh1jp hhhK~hj] hhubjq )}(h5Also, atomic_t values can be placed in debugfs with::h]h4Also, atomic_t values can be placed in debugfs with:}(hj& hhhNhNubah }(h ]h ]h"]h$]h&]uh1jp hhhKhj] hhubj )}(hvoid debugfs_create_atomic_t(const char *name, umode_t mode,
struct dentry *parent, atomic_t *value)h]hvoid debugfs_create_atomic_t(const char *name, umode_t mode,
struct dentry *parent, atomic_t *value)}hj4 sbah }(h ]h ]h"]h$]h&]hhuh1j hhhKhj] hhubjq )}(h`A read of this file will get atomic_t values, and a write of this file
will set atomic_t values.h]h`A read of this file will get atomic_t values, and a write of this file
will set atomic_t values.}(hjB hhhNhNubah }(h ]h ]h"]h$]h&]uh1jp hhhKhj] hhubjq )}(h`Another option is exporting a block of arbitrary binary data, with
this structure and function::h]h_Another option is exporting a block of arbitrary binary data, with
this structure and function:}(hjP hhhNhNubah }(h ]h ]h"]h$]h&]uh1jp hhhKhj] hhubj )}(hX
struct debugfs_blob_wrapper {
void *data;
unsigned long size;
};
struct dentry *debugfs_create_blob(const char *name, umode_t mode,
struct dentry *parent,
struct debugfs_blob_wrapper *blob);h]hX
struct debugfs_blob_wrapper {
void *data;
unsigned long size;
};
struct dentry *debugfs_create_blob(const char *name, umode_t mode,
struct dentry *parent,
struct debugfs_blob_wrapper *blob);}hj^ sbah }(h ]h ]h"]h$]h&]hhuh1j hhhKhj] hhubjq )}(hX A read of this file will return the data pointed to by the
debugfs_blob_wrapper structure. Some drivers use "blobs" as a simple way
to return several lines of (static) formatted text output. This function
can be used to export binary information, but there does not appear to be
any code which does so in the mainline. Note that all files created with
debugfs_create_blob() are read-only.h]hX A read of this file will return the data pointed to by the
debugfs_blob_wrapper structure. Some drivers use “blobs” as a simple way
to return several lines of (static) formatted text output. This function
can be used to export binary information, but there does not appear to be
any code which does so in the mainline. Note that all files created with
debugfs_create_blob() are read-only.}(hjl hhhNhNubah }(h ]h ]h"]h$]h&]uh1jp hhhKhj] hhubjq )}(hX If you want to dump a block of registers (something that happens quite
often during development, even if little such code reaches mainline),
debugfs offers two functions: one to make a registers-only file, and
another to insert a register block in the middle of another sequential
file::h]hX If you want to dump a block of registers (something that happens quite
often during development, even if little such code reaches mainline),
debugfs offers two functions: one to make a registers-only file, and
another to insert a register block in the middle of another sequential
file:}(hjz hhhNhNubah }(h ]h ]h"]h$]h&]uh1jp hhhKhj] hhubj )}(hX% struct debugfs_reg32 {
char *name;
unsigned long offset;
};
struct debugfs_regset32 {
const struct debugfs_reg32 *regs;
int nregs;
void __iomem *base;
struct device *dev; /* Optional device for Runtime PM */
};
debugfs_create_regset32(const char *name, umode_t mode,
struct dentry *parent,
struct debugfs_regset32 *regset);
void debugfs_print_regs32(struct seq_file *s, const struct debugfs_reg32 *regs,
int nregs, void __iomem *base, char *prefix);h]hX% struct debugfs_reg32 {
char *name;
unsigned long offset;
};
struct debugfs_regset32 {
const struct debugfs_reg32 *regs;
int nregs;
void __iomem *base;
struct device *dev; /* Optional device for Runtime PM */
};
debugfs_create_regset32(const char *name, umode_t mode,
struct dentry *parent,
struct debugfs_regset32 *regset);
void debugfs_print_regs32(struct seq_file *s, const struct debugfs_reg32 *regs,
int nregs, void __iomem *base, char *prefix);}hj sbah }(h ]h ]h"]h$]h&]hhuh1j hhhKhj] hhubjq )}(hThe "base" argument may be 0, but you may want to build the reg32 array
using __stringify, and a number of register names (macros) are actually
byte offsets over a base for the register block.h]hThe “base” argument may be 0, but you may want to build the reg32 array
using __stringify, and a number of register names (macros) are actually
byte offsets over a base for the register block.}(hj hhhNhNubah }(h ]h ]h"]h$]h&]uh1jp hhhKhj] hhubjq )}(hHIf you want to dump a u32 array in debugfs, you can create a file with::h]hGIf you want to dump a u32 array in debugfs, you can create a file with:}(hj hhhNhNubah }(h ]h ]h"]h$]h&]uh1jp hhhKhj] hhubj )}(hstruct debugfs_u32_array {
u32 *array;
u32 n_elements;
};
void debugfs_create_u32_array(const char *name, umode_t mode,
struct dentry *parent,
struct debugfs_u32_array *array);h]hstruct debugfs_u32_array {
u32 *array;
u32 n_elements;
};
void debugfs_create_u32_array(const char *name, umode_t mode,
struct dentry *parent,
struct debugfs_u32_array *array);}hj sbah }(h ]h ]h"]h$]h&]hhuh1j hhhKhj] hhubjq )}(hThe "array" argument wraps a pointer to the array's data and the number
of its elements. Note: Once array is created its size can not be changed.h]hThe “array” argument wraps a pointer to the array’s data and the number
of its elements. Note: Once array is created its size can not be changed.}(hj hhhNhNubah }(h ]h ]h"]h$]h&]uh1jp hhhKhj] hhubjq )}(h@There is a helper function to create a device-related seq_file::h]h?There is a helper function to create a device-related seq_file:}(hj hhhNhNubah }(h ]h ]h"]h$]h&]uh1jp hhhKhj] hhubj )}(hX
void debugfs_create_devm_seqfile(struct device *dev,
const char *name,
struct dentry *parent,
int (*read_fn)(struct seq_file *s,
void *data));h]hX
void debugfs_create_devm_seqfile(struct device *dev,
const char *name,
struct dentry *parent,
int (*read_fn)(struct seq_file *s,
void *data));}hj sbah }(h ]h ]h"]h$]h&]hhuh1j hhhKhj] hhubjq )}(hThe "dev" argument is the device related to this debugfs file, and
the "read_fn" is a function pointer which to be called to print the
seq_file content.h]hThe “dev” argument is the device related to this debugfs file, and
the “read_fn” is a function pointer which to be called to print the
seq_file content.}(hj hhhNhNubah }(h ]h ]h"]h$]h&]uh1jp hhhKhj] hhubjq )}(hAThere are a couple of other directory-oriented helper functions::h]h@There are a couple of other directory-oriented helper functions:}(hj hhhNhNubah }(h ]h ]h"]h$]h&]uh1jp hhhKhj] hhubj )}(hX' struct dentry *debugfs_change_name(struct dentry *dentry,
const char *fmt, ...);
struct dentry *debugfs_create_symlink(const char *name,
struct dentry *parent,
const char *target);h]hX' struct dentry *debugfs_change_name(struct dentry *dentry,
const char *fmt, ...);
struct dentry *debugfs_create_symlink(const char *name,
struct dentry *parent,
const char *target);}hj sbah }(h ]h ]h"]h$]h&]hhuh1j hhhKhj] hhubjq )}(hX A call to debugfs_change_name() will give a new name to an existing debugfs
file, always in the same directory. The new_name must not exist prior
to the call; the return value is 0 on success and -E... on failure.
Symbolic links can be created with debugfs_create_symlink().h]hX A call to debugfs_change_name() will give a new name to an existing debugfs
file, always in the same directory. The new_name must not exist prior
to the call; the return value is 0 on success and -E... on failure.
Symbolic links can be created with debugfs_create_symlink().}(hj hhhNhNubah }(h ]h ]h"]h$]h&]uh1jp hhhKhj] hhubjq )}(hX There is one important thing that all debugfs users must take into account:
there is no automatic cleanup of any directories created in debugfs. If a
module is unloaded without explicitly removing debugfs entries, the result
will be a lot of stale pointers and no end of highly antisocial behavior.
So all debugfs users - at least those which can be built as modules - must
be prepared to remove all files and directories they create there. A file
or directory can be removed with::h]hX There is one important thing that all debugfs users must take into account:
there is no automatic cleanup of any directories created in debugfs. If a
module is unloaded without explicitly removing debugfs entries, the result
will be a lot of stale pointers and no end of highly antisocial behavior.
So all debugfs users - at least those which can be built as modules - must
be prepared to remove all files and directories they create there. A file
or directory can be removed with:}(hj" hhhNhNubah }(h ]h ]h"]h$]h&]uh1jp hhhKhj] hhubj )}(h+void debugfs_remove(struct dentry *dentry);h]h+void debugfs_remove(struct dentry *dentry);}hj0 sbah }(h ]h ]h"]h$]h&]hhuh1j hhhKhj] hhubjq )}(hXp The dentry value can be NULL or an error value, in which case nothing will
be removed. Note that this function will recursively remove all files and
directories underneath it. Previously, debugfs_remove_recursive() was used
to perform that task, but this function is now just an alias to
debugfs_remove(). debugfs_remove_recursive() should be considered
deprecated.h]hXp The dentry value can be NULL or an error value, in which case nothing will
be removed. Note that this function will recursively remove all files and
directories underneath it. Previously, debugfs_remove_recursive() was used
to perform that task, but this function is now just an alias to
debugfs_remove(). debugfs_remove_recursive() should be considered
deprecated.}(hj> hhhNhNubah }(h ]h ]h"]h$]h&]uh1jp hhhKhj] hhubhfootnote)}(h http://lwn.net/Articles/309298/h](hlabel)}(h1h]h1}(hjT hhhNhNubah }(h ]h ]h"]h$]h&]uh1jR hjN ubjq )}(hjP h]j )}(hjP h]h http://lwn.net/Articles/309298/}(hje hhhNhNubah }(h ]h ]h"]h$]h&]refurijP uh1j hjb ubah }(h ]h ]h"]h$]h&]uh1jp hhhKhjN ubeh }(h ]j ah ]h"]1ah$]h&]j aj j uh1jL hhhKhj] hhj Kubeh }(h ]debugfsah ]h"]debugfsah$]h&]uh1j[ hhhhhhhKubeh }(h ]h ]h"]h$]h&]sourcehuh1hcurrent_sourceN current_lineNsettingsdocutils.frontendValues)}(j` N generatorN datestampN source_linkN
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