efi: add efivars kobject to efi sysfs folder
Subsystems (2)
PATCH 1/1 efi: add efivars kobject to efi sysfs folder
UEFI variable filesystem need a new mount point, so this patch add efivars kobject to efi_kobj for create a /sys/firmware/efi/efivars folder.
--- drivers/firmware/efivars.c | 11 +++++++++++ include/linux/efi.h | 1 + 2 files changed, 12 insertions(+), 0 deletions(-)
drivers/firmware/efivars.c +11 -0
@@ -1487,6 +1487,7 @@ void unregister_efivars(struct efivars *efivars)sysfs_remove_bin_file (&efivars->kset->kobj, efivars->del_var);kfree (efivars->new_var);kfree (efivars->del_var); +kobject_put (efivars->kobject);kset_unregister (efivars->kset); }EXPORT_SYMBOL_GPL (unregister_efivars);
@@ -1518,6 +1519,13 @@ int register_efivars(struct efivars *efivars, goto out; } + efivars->kobject =kobject_create_and_add ("efivars" , parent_kobj); +if (!efivars->kobject) { +pr_err ("efivars: Subsystem registration failed.\n" ); + error = -ENOMEM ; + goto err_unreg_vars; + } +/* * Per EFI spec, the maximum storage allocated for both * the variable name and variable data is 1024 bytes.
@@ -1562,6 +1570,9 @@ int register_efivars(struct efivars *efivars,register_filesystem (&efivars_fs_type); +err_unreg_vars: +kset_unregister (efivars->kset); + out:kfree (variable_name);
include/linux/efi.h +1 -0
@@ -654,6 +654,7 @@ struct efivars {spinlock_t lock;struct list_head list;struct kset *kset; +struct kobject *kobject;struct bin_attribute *new_var, *del_var;const struct efivar_operations *ops;struct efivar_entry *walk_entry;
Signature · 1 line
1.7.7
Quoted 9 lines · Chun-Yi
UEFI variable filesystem need a new mount point, so this patch add efivars kobject to
efi_kobjfor create a/sys/firmware/efi/efivarsfolder.Cc Matt Fleming <[email protected]>Cc Jeremy Kerr <[email protected]>Cc Matthew Garrett <[email protected]>Cc H. Peter Anvin <[email protected]>Signed-off-by Lee, Chun-Yi <[email protected]>
Quoted 4 lines
--- drivers/firmware/efivars.c | 11 +++++++++++ include/linux/efi.h | 1 + 2 files changed, 12 insertions(+), 0 deletions(-)
Jeremy, did you want to pick this up as part of your series?
Actually, shouldn't the new filesystem be called "efivarfs", or "efifs" to make it more explicit that it is a filesystem?
We also need something in Documentation/filesystems/ describing the old EFI variable method, why it's no longer any good, and why the new filesystem is favoured. Does anybody have anything to add to the following?
Documentation/filesystems/00-INDEX +2 -0
@@ -38,6 +38,8 @@ dnotify_test.c - example program for dnotify ecryptfs.txt - docs on eCryptfs: stacked cryptographic filesystem for Linux. +efivars.txt + - info for the efivars filesystem. exofs.txt - info, usage, mount options, design about EXOFS. ext2.txt
Documentation/filesystems/efivars.txt new file +16 -0
@@ -0,0 +1,16 @@ + +efivars - a (U)EFI variable filesystem + +The efivars 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 efivars +filesystem. + +The efivars filesystem is typically mounted like this, + + mount -t efivars none /sys/firmware/efi/efivars
Hi Matt,
Quoted 1 line
Jeremy, did you want to pick this up as part of your series?
I have this in my series, yes. I'm just working on the authenticated delete code, then will send out the next revision.
Speaking of which - Peter: I've realised that doing a GetVariable() after the SetVariable is a much cleaner way of checking whether we need to drop the inode after an authenticated delete.
Because the inode's size may not be simply updated by the write(), we should probably be doing a GetVariable() after an APPEND_WRITE, to read the new size. Rather than having a separate (and quite complex) code path to check for the delete case, we may as well use the same logic to determine if the variable has been deleted.
Quoted 2 lines
Actually, shouldn't the new filesystem be called "efivarfs", or "efifs" to make it more explicit that it is a filesystem?
I'm not too fussed about the name, but +1 for efivarfs.
Quoted 4 lines
We also need something in
Documentation/filesystems/describing the old EFI variable method, why it's no longer any good, and why the new filesystem is favoured. Does anybody have anything to add to the following?
Looks good to me. We can always elaborate later, if necessary.
Cheers,
Jeremy
Quoted 11 lines · Jeremy Kerr
Hi Matt,
Quoted 1 line
Jeremy, did you want to pick this up as part of your series?
I have this in my series, yes. I'm just working on the authenticated delete code, then will send out the next revision.
Speaking of which - Peter: I've realised that doing a
GetVariable()after the SetVariable is a much cleaner way of checking whether we need to drop the inode after an authenticated delete.
Quoted 5 lines
Because the inode's size may not be simply updated by the
write(), we should probably be doing aGetVariable()after anAPPEND_WRITE, to read the new size. Rather than having a separate (and quite complex) code path to check for the delete case, we may as well use the same logic to determine if the variable has been deleted.
Yeah, this is fine.
Quoted 4 lines
Quoted 2 lines
Actually, shouldn't the new filesystem be called "efivarfs", or "efifs" to make it more explicit that it is a filesystem?
I'm not too fussed about the name, but +1 for efivarfs.
I like efivarfs for the name, as well.
Quoted 6 lines
Quoted 4 lines
We also need something in
Documentation/filesystems/describing the old EFI variable method, why it's no longer any good, and why the new filesystem is favoured. Does anybody have anything to add to the following?Looks good to me. We can always elaborate later, if necessary.
Yep.
Signature · 1 line
Peter
於 四，2012-10-04 於 09:54 +0100，Matt Fleming 提到：
Quoted 15 lines · Chun-Yi
Quoted 9 lines
UEFI variable filesystem need a new mount point, so this patch add efivars kobject to
efi_kobjfor create a/sys/firmware/efi/efivarsfolder.Cc Matt Fleming <[email protected]>Cc Jeremy Kerr <[email protected]>Cc Matthew Garrett <[email protected]>Cc H. Peter Anvin <[email protected]>Signed-off-by Lee, Chun-Yi <[email protected]>Quoted 4 lines
--- drivers/firmware/efivars.c | 11 +++++++++++ include/linux/efi.h | 1 + 2 files changed, 12 insertions(+), 0 deletions(-)
Quoted 2 lines
Actually, shouldn't the new filesystem be called "efivarfs", or "efifs" to make it more explicit that it is a filesystem?
I used "efivars" because this folder generated by efivars. But, I like your suggestion for use "efivarfs", it's better then "efivars".
Quoted 32 lines
We also need something in
Documentation/filesystems/describing the old EFI variable method, why it's no longer any good, and why the new filesystem is favoured. Does anybody have anything to add to the following?Documentation/filesystems/00-INDEX +2
-0@@ -38,6 +38,8 @@ dnotify_test.c - example program for dnotify ecryptfs.txt - docs on eCryptfs: stacked cryptographic filesystem for Linux. +efivars.txt + - info for the efivars filesystem. exofs.txt - info, usage, mount options, design about EXOFS. ext2.txtDocumentation/filesystems/efivars.txt new file +6
-0@@ -0,0 +1,16 @@ + +efivars - a (U)EFI variable filesystem + +The efivars 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
Documentation/filesystems/efivars.txt line 16
Quoted 10 lines
Documentation/filesystems/efivars.txt new file +10
-0+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 efivars +filesystem. + +The efivars filesystem is typically mounted like this, + + mount -t efivars none /sys/firmware/efi/efivars
The above documentation is really good!
Thanks a lot!
Joey Lee