€•r$Œsphinx.addnodes”Œdocument”“”)”}”(Œ rawsource”Œ”Œchildren”]”(Œ translations”Œ LanguagesNode”“”)”}”(hhh]”(hŒ pending_xref”“”)”}”(hhh]”Œdocutils.nodes”ŒText”“”ŒChinese (Simplified)”…””}”Œparent”hsbaŒ attributes”}”(Œids”]”Œclasses”]”Œnames”]”Œdupnames”]”Œbackrefs”]”Œ refdomain”Œstd”Œreftype”Œdoc”Œ reftarget”Œ(/translations/zh_CN/filesystems/efivarfs”Œmodname”NŒ classname”NŒ refexplicit”ˆuŒtagname”hhh ubh)”}”(hhh]”hŒChinese (Traditional)”…””}”hh2sbah}”(h]”h ]”h"]”h$]”h&]”Œ refdomain”h)Œreftype”h+Œ reftarget”Œ(/translations/zh_TW/filesystems/efivarfs”Œmodname”NŒ classname”NŒ refexplicit”ˆuh1hhh ubh)”}”(hhh]”hŒItalian”…””}”hhFsbah}”(h]”h ]”h"]”h$]”h&]”Œ refdomain”h)Œreftype”h+Œ reftarget”Œ(/translations/it_IT/filesystems/efivarfs”Œmodname”NŒ classname”NŒ refexplicit”ˆuh1hhh ubh)”}”(hhh]”hŒJapanese”…””}”hhZsbah}”(h]”h ]”h"]”h$]”h&]”Œ refdomain”h)Œreftype”h+Œ reftarget”Œ(/translations/ja_JP/filesystems/efivarfs”Œmodname”NŒ classname”NŒ refexplicit”ˆuh1hhh ubh)”}”(hhh]”hŒKorean”…””}”hhnsbah}”(h]”h ]”h"]”h$]”h&]”Œ refdomain”h)Œreftype”h+Œ reftarget”Œ(/translations/ko_KR/filesystems/efivarfs”Œmodname”NŒ classname”NŒ refexplicit”ˆuh1hhh ubh)”}”(hhh]”hŒSpanish”…””}”hh‚sbah}”(h]”h ]”h"]”h$]”h&]”Œ refdomain”h)Œreftype”h+Œ reftarget”Œ(/translations/sp_SP/filesystems/efivarfs”Œmodname”NŒ classname”NŒ refexplicit”ˆuh1hhh ubeh}”(h]”h ]”h"]”h$]”h&]”Œcurrent_language”ŒEnglish”uh1h hhŒ _document”hŒsource”NŒline”NubhŒcomment”“”)”}”(hŒ SPDX-License-Identifier: GPL-2.0”h]”hŒ SPDX-License-Identifier: GPL-2.0”…””}”hh£sbah}”(h]”h ]”h"]”h$]”h&]”Œ xml:space”Œpreserve”uh1h¡hhhžhhŸŒB/var/lib/git/docbuild/linux/Documentation/filesystems/efivarfs.rst”h KubhŒsection”“”)”}”(hhh]”(hŒtitle”“”)”}”(hŒ'efivarfs - a (U)EFI variable filesystem”h]”hŒ'efivarfs - a (U)EFI variable filesystem”…””}”(hh»hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h¹hh¶hžhhŸh³h KubhŒ paragraph”“”)”}”(hXŽThe efivarfs filesystem was created to address the shortcomings of using entries in sysfs to maintain EFI variables. The old sysfs EFI variables code only supported variables of up to 1024 bytes. This limitation existed in version 0.99 of the EFI specification, but was removed before any full releases. Since variables can now be larger than a single page, sysfs isn't the best interface for this.”h]”hXThe efivarfs filesystem was created to address the shortcomings of using entries in sysfs to maintain EFI variables. The old sysfs EFI variables code only supported variables of up to 1024 bytes. This limitation existed in version 0.99 of the EFI specification, but was removed before any full releases. Since variables can now be larger than a single page, sysfs isn’t the best interface for this.”…””}”(hhËhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÉhŸh³h Khh¶hžhubhÊ)”}”(hŒLVariables can be created, deleted and modified with the efivarfs filesystem.”h]”hŒLVariables can be created, deleted and modified with the efivarfs filesystem.”…””}”(hhÙhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÉhŸh³h Khh¶hžhubhÊ)”}”(hŒ)efivarfs is typically mounted like this::”h]”hŒ(efivarfs is typically mounted like this:”…””}”(hhçhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÉhŸh³h Khh¶hžhubhŒ literal_block”“”)”}”(hŒ0mount -t efivarfs none /sys/firmware/efi/efivars”h]”hŒ0mount -t efivarfs none /sys/firmware/efi/efivars”…””}”hh÷sbah}”(h]”h ]”h"]”h$]”h&]”h±h²uh1hõhŸh³h Khh¶hžhubhÊ)”}”(hXiDue to the presence of numerous firmware bugs where removing non-standard UEFI variables causes the system firmware to fail to POST, efivarfs files that are not well-known standardized variables are created as immutable files. This doesn't prevent removal - "chattr -i" will work - but it does prevent this kind of failure from being accomplished accidentally.”h]”hXoDue to the presence of numerous firmware bugs where removing non-standard UEFI variables causes the system firmware to fail to POST, efivarfs files that are not well-known standardized variables are created as immutable files. This doesn’t prevent removal - “chattr -i†will work - but it does prevent this kind of failure from being accomplished accidentally.”…””}”(hjhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÉhŸh³h Khh¶hžhubhŒwarning”“”)”}”(hX”When a content of an UEFI variable in /sys/firmware/efi/efivars is displayed, for example using "hexdump", pay attention that the first 4 bytes of the output represent the UEFI variable attributes, in little-endian format. Practically the output of each efivar is composed of: +-----------------------------------+ |4_bytes_of_attributes + efivar_data| +-----------------------------------+”h]”(hÊ)”}”(hŒÞWhen a content of an UEFI variable in /sys/firmware/efi/efivars is displayed, for example using "hexdump", pay attention that the first 4 bytes of the output represent the UEFI variable attributes, in little-endian format.”h]”hŒâWhen a content of an UEFI variable in /sys/firmware/efi/efivars is displayed, for example using “hexdumpâ€, pay attention that the first 4 bytes of the output represent the UEFI variable attributes, in little-endian format.”…””}”(hjhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÉhŸh³h KhjubhÊ)”}”(hŒ5Practically the output of each efivar is composed of:”h]”hŒ5Practically the output of each efivar is composed of:”…””}”(hj'hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÉhŸh³h K"hjubhŒ block_quote”“”)”}”(hŒq+-----------------------------------+ |4_bytes_of_attributes + efivar_data| +-----------------------------------+”h]”hŒtable”“”)”}”(hhh]”hŒtgroup”“”)”}”(hhh]”(hŒcolspec”“”)”}”(hhh]”h}”(h]”h ]”h"]”h$]”h&]”Œcolwidth”K#uh1jEhjBubhŒtbody”“”)”}”(hhh]”hŒrow”“”)”}”(hhh]”hŒentry”“”)”}”(hhh]”hÊ)”}”(hŒ#4_bytes_of_attributes + efivar_data”h]”hŒ#4_bytes_of_attributes + efivar_data”…””}”(hj`hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÉhŸh³h K%hj]ubah}”(h]”h ]”h"]”h$]”h&]”uh1j[hjXubah}”(h]”h ]”h"]”h$]”h&]”uh1jVhjSubah}”(h]”h ]”h"]”h$]”h&]”uh1jQhjBubeh}”(h]”h ]”h"]”h$]”h&]”Œcols”Kuh1j@hj=ubah}”(h]”h ]”h"]”h$]”h&]”uh1j;hj7ubah}”(h]”h ]”h"]”h$]”h&]”uh1j5hŸh³h K$hjubeh}”(h]”h ]”h"]”h$]”h&]”uh1jhh¶hžhhŸh³h NubhÊ)”}”(hŒ *See also:*”h]”hŒemphasis”“”)”}”(hj›h]”hŒ See also:”…””}”(hjŸhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1jhj™ubah}”(h]”h ]”h"]”h$]”h&]”uh1hÉhŸh³h K(hh¶hžhubhŒ bullet_list”“”)”}”(hhh]”(hŒ list_item”“”)”}”(hŒ0Documentation/admin-guide/acpi/ssdt-overlays.rst”h]”hÊ)”}”(hj»h]”hŒ0Documentation/admin-guide/acpi/ssdt-overlays.rst”…””}”(hj½hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÉhŸh³h K*hj¹ubah}”(h]”h ]”h"]”h$]”h&]”uh1j·hj´hžhhŸh³h Nubj¸)”}”(hŒ1Documentation/ABI/removed/sysfs-firmware-efi-vars”h]”hÊ)”}”(hjÒh]”hŒ1Documentation/ABI/removed/sysfs-firmware-efi-vars”…””}”(hjÔhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1hÉhŸh³h K+hjÐubah}”(h]”h ]”h"]”h$]”h&]”uh1j·hj´hžhhŸh³h Nubeh}”(h]”h ]”h"]”h$]”h&]”Œbullet”Œ-”uh1j²hŸh³h K*hh¶hžhubeh}”(h]”Œ$efivarfs-a-u-efi-variable-filesystem”ah ]”h"]”Œ'efivarfs - a (u)efi variable filesystem”ah$]”h&]”uh1h´hhhžhhŸh³h Kubeh}”(h]”h ]”h"]”h$]”h&]”Œsource”h³uh1hŒcurrent_source”NŒ current_line”NŒsettings”Œdocutils.frontend”ŒValues”“”)”}”(h¹NŒ generator”NŒ datestamp”NŒ source_link”NŒ source_url”NŒ toc_backlinks”j[Œfootnote_backlinks”KŒ sectnum_xform”KŒstrip_comments”NŒstrip_elements_with_classes”NŒ strip_classes”NŒ report_level”KŒ halt_level”KŒexit_status_level”KŒdebug”NŒwarning_stream”NŒ traceback”ˆŒinput_encoding”Œ utf-8-sig”Œinput_encoding_error_handler”Œstrict”Œoutput_encoding”Œutf-8”Œoutput_encoding_error_handler”jŒerror_encoding”Œutf-8”Œerror_encoding_error_handler”Œbackslashreplace”Œ language_code”Œen”Œrecord_dependencies”NŒconfig”NŒ id_prefix”hŒauto_id_prefix”Œid”Œ dump_settings”NŒdump_internals”NŒdump_transforms”NŒdump_pseudo_xml”NŒexpose_internals”NŒstrict_visitor”NŒ_disable_config”NŒ_source”h³Œ _destination”NŒ _config_files”]”Œ7/var/lib/git/docbuild/linux/Documentation/docutils.conf”aŒfile_insertion_enabled”ˆŒ raw_enabled”KŒline_length_limit”M'Œpep_references”NŒ pep_base_url”Œhttps://peps.python.org/”Œpep_file_url_template”Œpep-%04d”Œrfc_references”NŒ rfc_base_url”Œ&https://datatracker.ietf.org/doc/html/”Œ tab_width”KŒtrim_footnote_reference_space”‰Œsyntax_highlight”Œlong”Œ smart_quotes”ˆŒsmartquotes_locales”]”Œcharacter_level_inline_markup”‰Œdoctitle_xform”‰Œ docinfo_xform”KŒsectsubtitle_xform”‰Œ image_loading”Œlink”Œembed_stylesheet”‰Œcloak_email_addresses”ˆŒsection_self_link”‰Œenv”NubŒreporter”NŒindirect_targets”]”Œsubstitution_defs”}”Œsubstitution_names”}”Œrefnames”}”Œrefids”}”Œnameids”}”jôjñsŒ nametypes”}”jô‰sh}”jñh¶sŒ footnote_refs”}”Œ citation_refs”}”Œ autofootnotes”]”Œautofootnote_refs”]”Œsymbol_footnotes”]”Œsymbol_footnote_refs”]”Œ footnotes”]”Œ citations”]”Œautofootnote_start”KŒsymbol_footnote_start”KŒ id_counter”Œ collections”ŒCounter”“”}”…”R”Œparse_messages”]”Œtransform_messages”]”Œ transformer”NŒ include_log”]”Œ decoration”Nhžhub.