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  1. 30 Jun, 2022 3 commits
  3. 28 Jun, 2022 2 commits
  5. 24 Jun, 2022 8 commits
    • Ard Biesheuvel's avatar
      efi: vars: Drop __efivar_entry_iter() helper which is no longer used · 5ac94136
      Ard Biesheuvel authored 
      __efivar_entry_iter() uses a list iterator in a dubious way, i.e., it
assumes that the iteration variable always points to an object of the
appropriate type, even if the list traversal exhausts the list
completely, in which case it will point somewhere in the vicinity of the
list's anchor instead.

Fortunately, we no longer use this function so we can just get rid of it
entirely.
Signed-off-by: default avatarArd Biesheuvel <ardb@kernel.org>
      5ac94136
    • Ard Biesheuvel's avatar
      efi: vars: Use locking version to iterate over efivars linked lists · 3a75f9f2
      Ard Biesheuvel authored 
      Both efivars and efivarfs uses __efivar_entry_iter() to go over the
linked list that shadows the list of EFI variables held by the firmware,
but fail to call the begin/end helpers that are documented as a
prerequisite.

So switch to the proper version, which is efivar_entry_iter(). Given
that in both cases, efivar_entry_remove() is invoked with the lock held
already, don't take the lock there anymore.
Signed-off-by: default avatarArd Biesheuvel <ardb@kernel.org>
      3a75f9f2
    • Ard Biesheuvel's avatar
      efi: pstore: Omit efivars caching EFI varstore access layer · 85974825
      Ard Biesheuvel authored 
      Avoid the efivars layer and simply call the newly introduced EFI
varstore helpers instead. This simplifies the code substantially, and
also allows us to remove some hacks in the shared efivars layer that
were added for efi-pstore specifically.

In order to be able to delete the EFI variable associated with a record,
store the UTF-16 name of the variable in the pstore record's priv field.
That way, we don't have to make guesses regarding which variable the
record may have been loaded from.
Signed-off-by: default avatarArd Biesheuvel <ardb@kernel.org>
      85974825
    • Ard Biesheuvel's avatar
      efi: vars: Add thin wrapper around EFI get/set variable interface · 472831d4
      Ard Biesheuvel authored 
      The current efivars layer is a jumble of list iterators, shadow data
structures and safe variable manipulation helpers that really belong in
the efivarfs pseudo file system once the obsolete sysfs access method to
EFI variables is removed.

So split off a minimal efivar get/set variable API that reuses the
existing efivars_lock semaphore to mediate access to the various runtime
services, primarily to ensure that performing a SetVariable() on one CPU
while another is calling GetNextVariable() in a loop to enumerate the
contents of the EFI variable store does not result in surprises.
Signed-off-by: default avatarArd Biesheuvel <ardb@kernel.org>
      472831d4
    • Ard Biesheuvel's avatar
      efi: vars: Don't drop lock in the middle of efivar_init() · ec3507b2
      Ard Biesheuvel authored 
      Even though the efivars_lock lock is documented as protecting the
efivars->ops pointer (among other things), efivar_init() happily
releases and reacquires the lock for every EFI variable that it
enumerates. This used to be needed because the lock was originally a
spinlock, which prevented the callback that is invoked for every
variable from being able to sleep. However, releasing the lock could
potentially invalidate the ops pointer, but more importantly, it might
allow a SetVariable() runtime service call to take place concurrently,
and the UEFI spec does not define how this affects an enumeration that
is running in parallel using the GetNextVariable() runtime service,
which is what efivar_init() uses.

In the meantime, the lock has been converted into a semaphore, and the
only reason we need to drop the lock is because the efivarfs pseudo
filesystem driver will otherwise deadlock when it invokes the efivars
API from the callback to create the efivar_entry items and insert them
into the linked list. (EFI pstore is affected in a similar way)

So let's switch to helpers that can be used while the lock is already
taken. This way, we can hold on to the lock throughout the enumeration.
Signed-off-by: default avatarArd Biesheuvel <ardb@kernel.org>
      ec3507b2
    • Ard Biesheuvel's avatar
      pstore: Add priv field to pstore_record for backend specific use · 8ca869b2
      Ard Biesheuvel authored 
      The EFI pstore backend will need to store per-record variable name data
when we switch away from the efivars layer. Add a priv field to struct
pstore_record, and document it as holding a backend specific pointer
that is assumed to be a kmalloc()d buffer, and will be kfree()d when the
entire record is freed.
Acked-by: default avatarKees Cook <keescook@chromium.org>
Signed-off-by: default avatarArd Biesheuvel <ardb@kernel.org>
      8ca869b2
    • Ard Biesheuvel's avatar
      Input: applespi - avoid efivars API and invoke EFI services directly · f662092b
      Ard Biesheuvel authored 
      This driver abuses the efivar API, by using a few of its helpers on
entries that were not instantiated by the API itself. This is a problem
as future cleanup work on efivars is complicated by this.

So let's just switch to the get/set variable runtime wrappers directly.

Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: default avatarArd Biesheuvel <ardb@kernel.org>
      f662092b
    • Ard Biesheuvel's avatar
      selftests/kexec: remove broken EFI_VARS secure boot fallback check · c07d2475
      Ard Biesheuvel authored 
      Commit b433a52a ("selftests/kexec: update get_secureboot_mode")
refactored the code that discovers the EFI secure boot mode so it only
depends on either the efivars pseudo filesystem or the efivars sysfs
interface, but never both.

However, the latter version was not implemented correctly, given the
fact that the local 'efi_vars' variable never assumes a value. This
means the fallback has been dead code ever since it was introduced.

So let's drop the fallback altogether. The sysfs interface has been
deprecated for ~10 years now, and is only enabled on x86 to begin with,
so it is time to get rid of it entirely.
Reviewed-by: default avatarMimi Zohar <zohar@linux.ibm.com>
Signed-off-by: default avatarArd Biesheuvel <ardb@kernel.org>
      c07d2475
  7. 20 Jun, 2022 5 commits
  9. 15 Jun, 2022 6 commits
  11. 06 Jun, 2022 3 commits
  13. 05 Jun, 2022 13 commits
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