Skip to content

K
Kernel

openeuler / Kernel
1 年多 前同步成功

通知 8
Star 0
Fork 0
K
Kernel
切换分支/标签
  1. 04 10月, 2014 10 次提交
    • M
      rtc: Disable EFI rtc for x86 · 7efe6659
      由 Matt Fleming 提交于 
      commit da167ad7 ("rtc: ia64: allow other architectures to use EFI
RTC") inadvertently introduced a regression for x86 because we've been
careful not to enable the EFI rtc driver due to the generally buggy
implementations of the time-related EFI runtime services.

In fact, since the above commit was merged we've seen reports of crashes
on 32-bit tablets,

  https://bugzilla.kernel.org/show_bug.cgi?id=84241#c21

Disable it explicitly for x86 so that we don't give users false hope
that this driver will work - it won't, and your machine is likely to
crash.
Acked-by: NMark Salter <msalter@redhat.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: <stable@vger.kernel.org> # v3.17
Signed-off-by: NMatt Fleming <matt.fleming@intel.com>
      7efe6659
    • A
      efi: rtc-efi: Export platform:rtc-efi as module alias · 3f71f6da
      由 Ard Biesheuvel 提交于 
      When the rtc-efi driver is built as a module, we already register the
EFI rtc as a platform device if UEFI Runtime Services are enabled.
To wire it up to udev, and let the module be loaded automatically, we
need to export the 'platform:rtc-efi' alias from the module.
Signed-off-by: NArd Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Mark Salter <msalter@redhat.com>
Cc: Dave Young <dyoung@redhat.com>
Signed-off-by: NMatt Fleming <matt.fleming@intel.com>
      3f71f6da
    • M
      efi: Delete the in_nmi() conditional runtime locking · 60b4dc77
      由 Matt Fleming 提交于 
      commit 5dc3826d9f08 ("efi: Implement mandatory locking for UEFI Runtime
Services") implemented some conditional locking when accessing variable
runtime services that Ingo described as "pretty disgusting".

The intention with the !efi_in_nmi() checks was to avoid live-locks when
trying to write pstore crash data into an EFI variable. Such lockless
accesses are allowed according to the UEFI specification when we're in a
"non-recoverable" state, but whether or not things are implemented
correctly in actual firmware implementations remains an unanswered
question, and so it would seem sensible to avoid doing any kind of
unsynchronized variable accesses.

Furthermore, the efi_in_nmi() tests are inadequate because they don't
account for the case where we call EFI variable services from panic or
oops callbacks and aren't executing in NMI context. In other words,
live-locking is still possible.

Let's just remove the conditional locking altogether. Now we've got the
->set_variable_nonblocking() EFI variable operation we can abort if the
runtime lock is already held. Aborting is by far the safest option.

Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Matthew Garrett <mjg59@srcf.ucam.org>
Signed-off-by: NMatt Fleming <matt.fleming@intel.com>
      60b4dc77
    • M
      efi: Provide a non-blocking SetVariable() operation · 6d80dba1
      由 Matt Fleming 提交于 
      There are some circumstances that call for trying to write an EFI
variable in a non-blocking way. One such scenario is when writing pstore
data in efi_pstore_write() via the pstore_dump() kdump callback.

Now that we have an EFI runtime spinlock we need a way of aborting if
there is contention instead of spinning, since when writing pstore data
from the kdump callback, the runtime lock may already be held by the CPU
that's running the callback if we crashed in the middle of an EFI
variable operation.

The situation is sufficiently special that a new EFI variable operation
is warranted.

Introduce ->set_variable_nonblocking() for this use case. It is an
optional EFI backend operation, and need only be implemented by those
backends that usually acquire locks to serialize access to EFI
variables, as is the case for virt_efi_set_variable() where we now grab
the EFI runtime spinlock.

Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Matthew Garrett <mjg59@srcf.ucam.org>
Signed-off-by: NMatt Fleming <matt.fleming@intel.com>
      6d80dba1
    • M
      efi: Resolve some shadow warnings · b2fce819
      由 Mark Rustad 提交于 
      It is a really bad idea to declare variables or parameters that
have the same name as common types. It is valid C, but it gets
surprising if a macro expansion attempts to declare an inner
local with that type. Change the local names to eliminate the
hazard.

Change s16 => str16, s8 => str8.

This resolves warnings seen when using W=2 during make, for instance:

drivers/firmware/efi/vars.c: In function ‘dup_variable_bug’:
drivers/firmware/efi/vars.c:324:44: warning: declaration of ‘s16’ shadows a global declaration [-Wshadow]
 static void dup_variable_bug(efi_char16_t *s16, efi_guid_t *vendor_guid,

drivers/firmware/efi/vars.c:328:8: warning: declaration of ‘s8’ shadows a global declaration [-Wshadow]
  char *s8;
Signed-off-by: NMark Rustad <mark.d.rustad@intel.com>
Signed-off-by: NJeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: NMatt Fleming <matt.fleming@intel.com>
      b2fce819
    • L
      efi: Introduce efi_md_typeattr_format() · 98d2a6ca
      由 Laszlo Ersek 提交于 
      At the moment, there are three architectures debug-printing the EFI memory
map at initialization: x86, ia64, and arm64. They all use different format
strings, plus the EFI memory type and the EFI memory attributes are
similarly hard to decode for a human reader.

Introduce a helper __init function that formats the memory type and the
memory attributes in a unified way, to a user-provided character buffer.

The array "memory_type_name" is copied from the arm64 code, temporarily
duplicating it. The (otherwise optional) braces around each string literal
in the initializer list are dropped in order to match the kernel coding
style more closely. The element size is tightened from 32 to 20 bytes
(maximum actual string length + 1) so that we can derive the field width
from the element size.
Signed-off-by: NLaszlo Ersek <lersek@redhat.com>
Tested-by: NArd Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: NArd Biesheuvel <ard.biesheuvel@linaro.org>
[ Dropped useless 'register' keyword, which compiler will ignore ]
Signed-off-by: NMatt Fleming <matt.fleming@intel.com>
      98d2a6ca
    • D
      efi: Add kernel param efi=noruntime · 5ae3683c
      由 Dave Young 提交于 
      noefi kernel param means actually disabling efi runtime, Per suggestion
from Leif Lindholm efi=noruntime should be better. But since noefi is
already used in X86 thus just adding another param efi=noruntime for
same purpose.
Signed-off-by: NDave Young <dyoung@redhat.com>
Signed-off-by: NMatt Fleming <matt.fleming@intel.com>
      5ae3683c
    • D
      efi: Move noefi early param code out of x86 arch code · b2e0a54a
      由 Dave Young 提交于 
      noefi param can be used for arches other than X86 later, thus move it
out of x86 platform code.
Signed-off-by: NDave Young <dyoung@redhat.com>
Signed-off-by: NMatt Fleming <matt.fleming@intel.com>
      b2e0a54a
    • M
      efi: Add efi= parameter parsing to the EFI boot stub · 5a17dae4
      由 Matt Fleming 提交于 
      We need a way to customize the behaviour of the EFI boot stub, in
particular, we need a way to disable the "chunking" workaround, used
when reading files from the EFI System Partition.

One of my machines doesn't cope well when reading files in 1MB chunks to
a buffer above the 4GB mark - it appears that the "chunking" bug
workaround triggers another firmware bug. This was only discovered with
commit 4bf7111f ("x86/efi: Support initrd loaded above 4G"), and
that commit is perfectly valid. The symptom I observed was a corrupt
initrd rather than any kind of crash.

efi= is now used to specify EFI parameters in two very different
execution environments, the EFI boot stub and during kernel boot.

There is also a slight performance optimization by enabling efi=nochunk,
but that's offset by the fact that you're more likely to run into
firmware issues, at least on x86. This is the rationale behind leaving
the workaround enabled by default.

Also provide some documentation for EFI_READ_CHUNK_SIZE and why we're
using the current value of 1MB.
Tested-by: NArd Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Roy Franz <roy.franz@linaro.org>
Cc: Maarten Lankhorst <m.b.lankhorst@gmail.com>
Cc: Leif Lindholm <leif.lindholm@linaro.org>
Cc: Borislav Petkov <bp@suse.de>
Signed-off-by: NMatt Fleming <matt.fleming@intel.com>
      5a17dae4
    • A
      efi: Implement mandatory locking for UEFI Runtime Services · 161485e8
      由 Ard Biesheuvel 提交于 
      According to section 7.1 of the UEFI spec, Runtime Services are not fully
reentrant, and there are particular combinations of calls that need to be
serialized. Use a spinlock to serialize all Runtime Services with respect
to all others, even if this is more than strictly needed.

We've managed to get away without requiring a runtime services lock
until now because most of the interactions with EFI involve EFI
variables, and those operations are already serialised with
__efivars->lock.

Some of the assumptions underlying the decision whether locks are
needed or not (e.g., SetVariable() against ResetSystem()) may not
apply universally to all [new] architectures that implement UEFI.
Rather than try to reason our way out of this, let's just implement at
least what the spec requires in terms of locking.
Signed-off-by: NArd Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: NMatt Fleming <matt.fleming@intel.com>
      161485e8
  3. 16 8月, 2014 30 次提交