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authorMatt Fleming <matt.fleming@intel.com>2012-10-04 12:57:31 +0400
committerMatt Fleming <matt.fleming@intel.com>2012-10-30 14:39:18 +0400
commite913ca7d16d70b75367ff56a3b201980501d542c (patch)
tree96f0cd6b1672ed329861945e4aa2291b2d399f08 /Documentation/filesystems/efivarfs.txt
parent605e70c7aa1b7b0d554baf945630c1d606bbfbc3 (diff)
downloadlinux-e913ca7d16d70b75367ff56a3b201980501d542c.tar.xz
efivarfs: Add documentation for the EFI variable filesystem
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
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+efivarfs - a (U)EFI variable filesystem
+
+The 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.
+
+Variables can be created, deleted and modified with the efivarfs
+filesystem.
+
+efivarfs is typically mounted like this,
+
+ mount -t efivarfs none /sys/firmware/efi/efivars