linux-stable.git/arch/x86/platform, branch linux-3.9.y Linux kernel stable tree x86/efi: Fix dummy variable buffer allocation 2013-06-27T17:38:44+00:00 Ben Hutchings ben@decadent.org.uk 2013-06-16T20:27:12+00:00 5440f5d68b518339a9ee2fdc838c8caef19e36de commit b8cb62f82103083a6e8fa5470bfe634a2c06514d upstream. 1. Check for allocation failure 2. Clear the buffer contents, as they may actually be written to flash 3. Don't leak the buffer Compile-tested only. [ Tested successfully on my buggy ASUS machine - Matt ] Signed-off-by: Ben Hutchings <ben@decadent.org.uk> Signed-off-by: Matt Fleming <matt.fleming@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit b8cb62f82103083a6e8fa5470bfe634a2c06514d upstream.

1. Check for allocation failure
2. Clear the buffer contents, as they may actually be written to flash
3. Don't leak the buffer

Compile-tested only.

[ Tested successfully on my buggy ASUS machine - Matt ]

Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Modify UEFI anti-bricking code 2013-06-20T19:01:32+00:00 Matthew Garrett matthew.garrett@nebula.com 2013-06-01T20:06:20+00:00 d20f2aa7720253fee3cac2ac0dc179517a16efca commit f8b8404337de4e2466e2e1139ea68b1f8295974f upstream. This patch reworks the UEFI anti-bricking code, including an effective reversion of cc5a080c and 31ff2f20. It turns out that calling QueryVariableInfo() from boot services results in some firmware implementations jumping to physical addresses even after entering virtual mode, so until we have 1:1 mappings for UEFI runtime space this isn't going to work so well. Reverting these gets us back to the situation where we'd refuse to create variables on some systems because they classify deleted variables as "used" until the firmware triggers a garbage collection run, which they won't do until they reach a lower threshold. This results in it being impossible to install a bootloader, which is unhelpful. Feedback from Samsung indicates that the firmware doesn't need more than 5KB of storage space for its own purposes, so that seems like a reasonable threshold. However, there's still no guarantee that a platform will attempt garbage collection merely because it drops below this threshold. It seems that this is often only triggered if an attempt to write generates a genuine EFI_OUT_OF_RESOURCES error. We can force that by attempting to create a variable larger than the remaining space. This should fail, but if it somehow succeeds we can then immediately delete it. I've tested this on the UEFI machines I have available, but I don't have a Samsung and so can't verify that it avoids the bricking problem. Signed-off-by: Matthew Garrett <matthew.garrett@nebula.com> Signed-off-by: Lee, Chun-Y <jlee@suse.com> [ dummy variable cleanup ] Signed-off-by: Matt Fleming <matt.fleming@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit f8b8404337de4e2466e2e1139ea68b1f8295974f upstream.

This patch reworks the UEFI anti-bricking code, including an effective
reversion of cc5a080c and 31ff2f20. It turns out that calling
QueryVariableInfo() from boot services results in some firmware
implementations jumping to physical addresses even after entering virtual
mode, so until we have 1:1 mappings for UEFI runtime space this isn't
going to work so well.

Reverting these gets us back to the situation where we'd refuse to create
variables on some systems because they classify deleted variables as "used"
until the firmware triggers a garbage collection run, which they won't do
until they reach a lower threshold. This results in it being impossible to
install a bootloader, which is unhelpful.

Feedback from Samsung indicates that the firmware doesn't need more than
5KB of storage space for its own purposes, so that seems like a reasonable
threshold. However, there's still no guarantee that a platform will attempt
garbage collection merely because it drops below this threshold. It seems
that this is often only triggered if an attempt to write generates a
genuine EFI_OUT_OF_RESOURCES error. We can force that by attempting to
create a variable larger than the remaining space. This should fail, but if
it somehow succeeds we can then immediately delete it.

I've tested this on the UEFI machines I have available, but I don't have
a Samsung and so can't verify that it avoids the bricking problem.

Signed-off-by: Matthew Garrett <matthew.garrett@nebula.com>
Signed-off-by: Lee, Chun-Y <jlee@suse.com> [ dummy variable cleanup ]
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
x86,efi: Implement efi_no_storage_paranoia parameter 2013-04-17T14:13:38+00:00 Richard Weinberger richard@nod.at 2013-04-16T23:00:53+00:00 8c58bf3eec3b8fc8162fe557e9361891c20758f2 Using this parameter one can disable the storage_size/2 check if he is really sure that the UEFI does sane gc and fulfills the spec. This parameter is useful if a devices uses more than 50% of the storage by default. The Intel DQSW67 desktop board is such a sucker for exmaple. Signed-off-by: Richard Weinberger <richard@nod.at> Signed-off-by: Matt Fleming <matt.fleming@intel.com> 
Using this parameter one can disable the storage_size/2 check if
he is really sure that the UEFI does sane gc and fulfills the spec.

This parameter is useful if a devices uses more than 50% of the
storage by default.
The Intel DQSW67 desktop board is such a sucker for exmaple.

Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
efi: Export efi_query_variable_store() for efivars.ko 2013-04-16T16:34:07+00:00 Sergey Vlasov vsu@altlinux.ru 2013-04-16T14:31:09+00:00 3668011d4ad556224f7c012c1e870a6eaa0e59da Fixes build with CONFIG_EFI_VARS=m which was broken after the commit "x86, efivars: firmware bug workarounds should be in platform code". Signed-off-by: Sergey Vlasov <vsu@altlinux.ru> Signed-off-by: Matt Fleming <matt.fleming@intel.com> 
Fixes build with CONFIG_EFI_VARS=m which was broken after the commit
"x86, efivars: firmware bug workarounds should be in platform code".

Signed-off-by: Sergey Vlasov <vsu@altlinux.ru>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
efi: Distinguish between "remaining space" and actually used space 2013-04-15T20:33:05+00:00 Matthew Garrett matthew.garrett@nebula.com 2013-04-15T20:09:47+00:00 31ff2f20d9003e74991d135f56e503fe776c127c EFI implementations distinguish between space that is actively used by a variable and space that merely hasn't been garbage collected yet. Space that hasn't yet been garbage collected isn't available for use and so isn't counted in the remaining_space field returned by QueryVariableInfo(). Combined with commit 68d9298 this can cause problems. Some implementations don't garbage collect until the remaining space is smaller than the maximum variable size, and as a result check_var_size() will always fail once more than 50% of the variable store has been used even if most of that space is marked as available for garbage collection. The user is unable to create new variables, and deleting variables doesn't increase the remaining space. The problem that 68d9298 was attempting to avoid was one where certain platforms fail if the actively used space is greater than 50% of the available storage space. We should be able to calculate that by simply summing the size of each available variable and subtracting that from the total storage space. With luck this will fix the problem described in https://bugzilla.kernel.org/show_bug.cgi?id=55471 without permitting damage to occur to the machines 68d9298 was attempting to fix. Signed-off-by: Matthew Garrett <matthew.garrett@nebula.com> Signed-off-by: Matt Fleming <matt.fleming@intel.com> 
EFI implementations distinguish between space that is actively used by a
variable and space that merely hasn't been garbage collected yet. Space
that hasn't yet been garbage collected isn't available for use and so isn't
counted in the remaining_space field returned by QueryVariableInfo().

Combined with commit 68d9298 this can cause problems. Some implementations
don't garbage collect until the remaining space is smaller than the maximum
variable size, and as a result check_var_size() will always fail once more
than 50% of the variable store has been used even if most of that space is
marked as available for garbage collection. The user is unable to create
new variables, and deleting variables doesn't increase the remaining space.

The problem that 68d9298 was attempting to avoid was one where certain
platforms fail if the actively used space is greater than 50% of the
available storage space. We should be able to calculate that by simply
summing the size of each available variable and subtracting that from
the total storage space. With luck this will fix the problem described in
https://bugzilla.kernel.org/show_bug.cgi?id=55471 without permitting
damage to occur to the machines 68d9298 was attempting to fix.

Signed-off-by: Matthew Garrett <matthew.garrett@nebula.com>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
efi: Pass boot services variable info to runtime code 2013-04-15T20:31:09+00:00 Matthew Garrett matthew.garrett@nebula.com 2013-04-15T20:09:46+00:00 cc5a080c5d40c36089bb08a8a16fa3fc7047fe0f EFI variables can be flagged as being accessible only within boot services. This makes it awkward for us to figure out how much space they use at runtime. In theory we could figure this out by simply comparing the results from QueryVariableInfo() to the space used by all of our variables, but that fails if the platform doesn't garbage collect on every boot. Thankfully, calling QueryVariableInfo() while still inside boot services gives a more reliable answer. This patch passes that information from the EFI boot stub up to the efi platform code. Signed-off-by: Matthew Garrett <matthew.garrett@nebula.com> Signed-off-by: Matt Fleming <matt.fleming@intel.com> 
EFI variables can be flagged as being accessible only within boot services.
This makes it awkward for us to figure out how much space they use at
runtime. In theory we could figure this out by simply comparing the results
from QueryVariableInfo() to the space used by all of our variables, but
that fails if the platform doesn't garbage collect on every boot. Thankfully,
calling QueryVariableInfo() while still inside boot services gives a more
reliable answer. This patch passes that information from the EFI boot stub
up to the efi platform code.

Signed-off-by: Matthew Garrett <matthew.garrett@nebula.com>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
x86,efi: Check max_size only if it is non-zero. 2013-04-11T14:45:52+00:00 Richard Weinberger richard@nod.at 2013-04-10T08:59:34+00:00 7791c8423f1f7f4dad94e753bae67461d5b80be8 Some EFI implementations return always a MaximumVariableSize of 0, check against max_size only if it is non-zero. My Intel DQ67SW desktop board has such an implementation. Signed-off-by: Richard Weinberger <richard@nod.at> Signed-off-by: Matt Fleming <matt.fleming@intel.com> 
Some EFI implementations return always a MaximumVariableSize of 0,
check against max_size only if it is non-zero.
My Intel DQ67SW desktop board has such an implementation.

Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
x86, efivars: firmware bug workarounds should be in platform code 2013-04-09T10:34:05+00:00 Matt Fleming matt.fleming@intel.com 2013-03-25T09:14:30+00:00 a6e4d5a03e9e3587e88aba687d8f225f4f04c792 Let's not burden ia64 with checks in the common efivars code that we're not writing too much data to the variable store. That kind of thing is an x86 firmware bug, plain and simple. efi_query_variable_store() provides platforms with a wrapper in which they can perform checks and workarounds for EFI variable storage bugs. Cc: H. Peter Anvin <hpa@zytor.com> Cc: Matthew Garrett <mjg59@srcf.ucam.org> Signed-off-by: Matt Fleming <matt.fleming@intel.com> 
Let's not burden ia64 with checks in the common efivars code that we're not
writing too much data to the variable store. That kind of thing is an x86
firmware bug, plain and simple.

efi_query_variable_store() provides platforms with a wrapper in which they can
perform checks and workarounds for EFI variable storage bugs.

Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Matthew Garrett <mjg59@srcf.ucam.org>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
Merge branch 'x86-efi-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2013-02-28T00:17:42+00:00 Linus Torvalds torvalds@linux-foundation.org 2013-02-28T00:17:42+00:00 e3c4877de8b9d93bd47b6ee88eb594b1c1e10da5 Pull x86/EFI changes from Peter Anvin: - Improve the initrd handling in the EFI boot stub by allowing forward slashes in the pathname - from Chun-Yi Lee. - Cleanup code duplication in the EFI mixed kernel/firmware code - from Satoru Takeuchi. - efivarfs bug fixes for more strict filename validation, with lots of input from Al Viro. * 'x86-efi-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86, efi: remove duplicate code in setup_arch() by using, efi_is_native() efivarfs: guid part of filenames are case-insensitive efivarfs: Validate filenames much more aggressively efivarfs: Use sizeof() instead of magic number x86, efi: Allow slash in file path of initrd 
Pull x86/EFI changes from Peter Anvin:

 - Improve the initrd handling in the EFI boot stub by allowing forward
   slashes in the pathname - from Chun-Yi Lee.

 - Cleanup code duplication in the EFI mixed kernel/firmware code - from
   Satoru Takeuchi.

 - efivarfs bug fixes for more strict filename validation, with lots of
   input from Al Viro.

* 'x86-efi-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86, efi: remove duplicate code in setup_arch() by using, efi_is_native()
  efivarfs: guid part of filenames are case-insensitive
  efivarfs: Validate filenames much more aggressively
  efivarfs: Use sizeof() instead of magic number
  x86, efi: Allow slash in file path of initrd
Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2013-02-28T00:16:39+00:00 Linus Torvalds torvalds@linux-foundation.org 2013-02-28T00:16:39+00:00 18a44a7ff1075ce5157ac07cde573aca6b5e9973 Pull more x86 fixes from Peter Anvin: "Additional x86 fixes. Three of these patches are pure documentation, two are pretty trivial; the remaining one fixes boot problems on some non-BIOS machines." * 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86: Make sure we can boot in the case the BDA contains pure garbage x86, efi: Mark disable_runtime as __initdata x86, doc: Fix incorrect comment about 64-bit code segment descriptors doc, kernel-parameters: Document 'console=hvc<n>' doc, xen: Mention 'earlyprintk=xen' in the documentation. ACPI: Overriding ACPI tables via initrd only works with an initrd and on X86 
Pull more x86 fixes from Peter Anvin:
 "Additional x86 fixes.  Three of these patches are pure documentation,
  two are pretty trivial; the remaining one fixes boot problems on some
  non-BIOS machines."

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86: Make sure we can boot in the case the BDA contains pure garbage
  x86, efi: Mark disable_runtime as __initdata
  x86, doc: Fix incorrect comment about 64-bit code segment descriptors
  doc, kernel-parameters: Document 'console=hvc<n>'
  doc, xen: Mention 'earlyprintk=xen' in the documentation.
  ACPI: Overriding ACPI tables via initrd only works with an initrd and on X86