Commit Graph

82 Commits

Author SHA1 Message Date
Linus Torvalds 04c2eee5b9 Merge branch 'x86-efi-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 EFI fixes from Peter Anvin:
 "This is a collection of fixes for the EFI support.  The controversial
  bit here is a set of patches which bumps the boot protocol version as
  part of fixing some serious problems with the EFI handover protocol,
  used when booting under EFI using a bootloader as opposed to directly
  from EFI.  These changes should also make it a lot saner to support
  cross-mode 32/64-bit EFI booting in the future.  Getting these changes
  into 3.8 means we avoid presenting an inconsistent ABI to bootloaders.

  Other changes are display detection and fixing efivarfs."

* 'x86-efi-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86, efi: remove attribute check from setup_efi_pci
  x86, build: Dynamically find entry points in compressed startup code
  x86, efi: Fix PCI ROM handing in EFI boot stub, in 32-bit mode
  x86, efi: Fix 32-bit EFI handover protocol entry point
  x86, efi: Fix display detection in EFI boot stub
  x86, boot: Define the 2.12 bzImage boot protocol
  x86/boot: Fix minor fd leakage in tools/relocs.c
  x86, efi: Set runtime_version to the EFI spec revision
  x86, efi: fix 32-bit warnings in setup_efi_pci()
  efivarfs: Delete dentry from dcache in efivarfs_file_write()
  efivarfs: Never return ENOENT from firmware
  efi, x86: Pass a proper identity mapping in efi_call_phys_prelog
  efivarfs: Drop link count of the right inode
2013-01-31 17:10:36 +11:00
Matt Fleming 83e6818974 efi: Make 'efi_enabled' a function to query EFI facilities
Originally 'efi_enabled' indicated whether a kernel was booted from
EFI firmware. Over time its semantics have changed, and it now
indicates whether or not we are booted on an EFI machine with
bit-native firmware, e.g. 64-bit kernel with 64-bit firmware.

The immediate motivation for this patch is the bug report at,

    https://bugs.launchpad.net/ubuntu-cdimage/+bug/1040557

which details how running a platform driver on an EFI machine that is
designed to run under BIOS can cause the machine to become
bricked. Also, the following report,

    https://bugzilla.kernel.org/show_bug.cgi?id=47121

details how running said driver can also cause Machine Check
Exceptions. Drivers need a new means of detecting whether they're
running on an EFI machine, as sadly the expression,

    if (!efi_enabled)

hasn't been a sufficient condition for quite some time.

Users actually want to query 'efi_enabled' for different reasons -
what they really want access to is the list of available EFI
facilities.

For instance, the x86 reboot code needs to know whether it can invoke
the ResetSystem() function provided by the EFI runtime services, while
the ACPI OSL code wants to know whether the EFI config tables were
mapped successfully. There are also checks in some of the platform
driver code to simply see if they're running on an EFI machine (which
would make it a bad idea to do BIOS-y things).

This patch is a prereq for the samsung-laptop fix patch.

Cc: David Airlie <airlied@linux.ie>
Cc: Corentin Chary <corentincj@iksaif.net>
Cc: Matthew Garrett <mjg59@srcf.ucam.org>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: Olof Johansson <olof@lixom.net>
Cc: Peter Jones <pjones@redhat.com>
Cc: Colin Ian King <colin.king@canonical.com>
Cc: Steve Langasek <steve.langasek@canonical.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Konrad Rzeszutek Wilk <konrad@kernel.org>
Cc: Rafael J. Wysocki <rjw@sisk.pl>
Cc: <stable@vger.kernel.org>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
2013-01-30 11:51:59 -08:00
Matt Fleming 791eb564d2 efivarfs: Delete dentry from dcache in efivarfs_file_write()
Unlike the unlink path that is called from the VFS layer, we need to
call d_delete() ourselves when a variable is deleted in
efivarfs_file_write().

Failure to do so means we can access a stale struct efivar_entry when
reading/writing the file, which can result in the following oops,

  [   59.978216] general protection fault: 0000 [#1] SMP
  [   60.038660] CPU 9
  [   60.040501] Pid: 1001, comm: cat Not tainted 3.7.0-2.fc19.x86_64 #1 IBM System x3550 M3 -[7944I21]-/69Y4438
  [   60.050840] RIP: 0010:[<ffffffff810d5d1e>]  [<ffffffff810d5d1e>] __lock_acquire+0x5e/0x1bb0
  [   60.059198] RSP: 0018:ffff880270595ce8  EFLAGS: 00010046
  [   60.064500] RAX: 0000000000000046 RBX: 0000000000000002 RCX: 0000000000000000
  [   60.071617] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 6b6b6b6b6b6b6b83
  [   60.078735] RBP: ffff880270595dd8 R08: 0000000000000002 R09: 0000000000000000
  [   60.085852] R10: 6b6b6b6b6b6b6b83 R11: 0000000000000000 R12: 0000000000000000
  [   60.092971] R13: ffff88027170cd20 R14: 0000000000000000 R15: 0000000000000000
  [   60.100091] FS:  00007fc0c8ff3740(0000) GS:ffff880277000000(0000) knlGS:0000000000000000
  [   60.108164] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  [   60.113899] CR2: 0000000001520000 CR3: 000000026d594000 CR4: 00000000000007e0
  [   60.121016] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
  [   60.128135] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
  [   60.135254] Process cat (pid: 1001, threadinfo ffff880270594000, task ffff88027170cd20)
  [   60.143239] Stack:
  [   60.145251]  ffff880270595cf8 ffffffff81021da3 ffff880270595d08 ffffffff81021e19
  [   60.152714]  ffff880270595d38 ffffffff810acdb5 ffff880200000168 0000000000000086
  [   60.160175]  ffff88027170d5e8 ffffffff810d25ed ffff880270595d58 ffffffff810ace7f
  [   60.167638] Call Trace:
  [   60.170088]  [<ffffffff81021da3>] ? native_sched_clock+0x13/0x80
  [   60.176085]  [<ffffffff81021e19>] ? sched_clock+0x9/0x10
  [   60.181389]  [<ffffffff810acdb5>] ? sched_clock_cpu+0xc5/0x120
  [   60.187211]  [<ffffffff810d25ed>] ? trace_hardirqs_off+0xd/0x10
  [   60.193121]  [<ffffffff810ace7f>] ? local_clock+0x6f/0x80
  [   60.198513]  [<ffffffff810d2f6f>] ? lock_release_holdtime.part.26+0xf/0x180
  [   60.205465]  [<ffffffff810d7b57>] ? lock_release_non_nested+0x2e7/0x320
  [   60.212073]  [<ffffffff815638bb>] ? efivarfs_file_write+0x5b/0x280
  [   60.218242]  [<ffffffff810d7f41>] lock_acquire+0xa1/0x1f0
  [   60.223633]  [<ffffffff81563971>] ? efivarfs_file_write+0x111/0x280
  [   60.229892]  [<ffffffff8118b47c>] ? might_fault+0x5c/0xb0
  [   60.235287]  [<ffffffff816f1bf6>] _raw_spin_lock+0x46/0x80
  [   60.240762]  [<ffffffff81563971>] ? efivarfs_file_write+0x111/0x280
  [   60.247018]  [<ffffffff81563971>] efivarfs_file_write+0x111/0x280
  [   60.253103]  [<ffffffff811d307f>] vfs_write+0xaf/0x190
  [   60.258233]  [<ffffffff811d33d5>] sys_write+0x55/0xa0
  [   60.263278]  [<ffffffff816fbd19>] system_call_fastpath+0x16/0x1b
  [   60.269271] Code: 41 0f 45 d8 4c 89 75 f0 4c 89 7d f8 85 c0 0f 84 09 01 00 00 8b 05 a3 f9 ff 00 49 89 fa 41 89 f6 41 89 d3 85 c0 0f 84 12 01 00 00 <49> 8b 02 ba 01 00 00 00 48 3d a0 07 14 82 0f 44 da 41 83 fe 01
  [   60.289431] RIP  [<ffffffff810d5d1e>] __lock_acquire+0x5e/0x1bb0
  [   60.295444]  RSP <ffff880270595ce8>
  [   60.298928] ---[ end trace 1bbfd41a2cf6a0d8 ]---

Cc: Josh Boyer <jwboyer@redhat.com>
Acked-by: Jeremy Kerr <jeremy.kerr@canonical.com>
Cc: Lee, Chun-Yi <jlee@suse.com>
Cc: Andy Whitcroft <apw@canonical.com>
Reported-by: Lingzhu Xiang <lxiang@redhat.com>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
2013-01-18 09:43:44 +00:00
Matt Fleming 1fa7e6958c efivarfs: Never return ENOENT from firmware
Files are created in efivarfs_create() before a corresponding variable
is created in the firmware. This leads to users being able to
read/write to the file without the variable existing in the
firmware. Reading a non-existent variable currently returns -ENOENT,
which is confusing because the file obviously *does* exist.

Convert EFI_NOT_FOUND into -EIO which is the closest thing to "error
while interacting with firmware", and should hopefully indicate to the
caller that the variable is in some uninitialised state.

Cc: Josh Boyer <jwboyer@redhat.com>
Acked-by: Jeremy Kerr <jeremy.kerr@canonical.com>
Cc: Lee, Chun-Yi <jlee@suse.com>
Cc: Andy Whitcroft <apw@canonical.com>
Reported-by: Lingzhu Xiang <lxiang@redhat.com>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
2013-01-18 09:43:44 +00:00
Lingzhu Xiang de5fe95587 efivarfs: Drop link count of the right inode
efivarfs_unlink() should drop the file's link count, not the directory's.

Signed-off-by: Lingzhu Xiang <lxiang@redhat.com>
Cc: Jeremy Kerr <jeremy.kerr@canonical.com>
Tested-by: Lee, Chun-Yi <jlee@suse.com>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
2013-01-18 09:43:43 +00:00
Eric W. Biederman 992956189d efi: Fix the build with user namespaces enabled.
When compiling efivars.c the build fails with:

   CC      drivers/firmware/efivars.o
  drivers/firmware/efivars.c: In function ‘efivarfs_get_inode’:
  drivers/firmware/efivars.c:886:31: error: incompatible types when assigning to type ‘kgid_t’ from type ‘int’
  make[2]: *** [drivers/firmware/efivars.o] Error 1
  make[1]: *** [drivers/firmware/efivars.o] Error 2

Fix the build error by removing the duplicate initialization of i_uid and
i_gid inode_init_always has already initialized them to 0.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-17 20:14:15 -08:00
Linus Torvalds d42b3a2906 Merge branch 'core-efi-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 EFI update from Peter Anvin:
 "EFI tree, from Matt Fleming.  Most of the patches are the new efivarfs
  filesystem by Matt Garrett & co.  The balance are support for EFI
  wallclock in the absence of a hardware-specific driver, and various
  fixes and cleanups."

* 'core-efi-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (24 commits)
  efivarfs: Make efivarfs_fill_super() static
  x86, efi: Check table header length in efi_bgrt_init()
  efivarfs: Use query_variable_info() to limit kmalloc()
  efivarfs: Fix return value of efivarfs_file_write()
  efivarfs: Return a consistent error when efivarfs_get_inode() fails
  efivarfs: Make 'datasize' unsigned long
  efivarfs: Add unique magic number
  efivarfs: Replace magic number with sizeof(attributes)
  efivarfs: Return an error if we fail to read a variable
  efi: Clarify GUID length calculations
  efivarfs: Implement exclusive access for {get,set}_variable
  efivarfs: efivarfs_fill_super() ensure we clean up correctly on error
  efivarfs: efivarfs_fill_super() ensure we free our temporary name
  efivarfs: efivarfs_fill_super() fix inode reference counts
  efivarfs: efivarfs_create() ensure we drop our reference on inode on error
  efivarfs: efivarfs_file_read ensure we free data in error paths
  x86-64/efi: Use EFI to deal with platform wall clock (again)
  x86/kernel: remove tboot 1:1 page table creation code
  x86, efi: 1:1 pagetable mapping for virtual EFI calls
  x86, mm: Include the entire kernel memory map in trampoline_pgd
  ...
2012-12-14 10:08:40 -08:00
Seiji Aguchi f94ec0c059 efi_pstore: Add a format check for an existing variable name at erasing time
[Issue]

a format of variable name has been updated to type, id, count and ctime
to support holding multiple logs.

Format of current variable name
  dump-type0-1-2-12345678

  type:0
  id:1
  count:2
  ctime:12345678

On the other hand, if an old variable name before being updated
remains, users can't erase it via /dev/pstore.

Format of old variable name
  dump-type0-1-12345678

  type:0
  id:1
  ctime:12345678

[Solution]

This patch add a format check for the old variable name in a erase callback to make it erasable.

Signed-off-by: Seiji Aguchi <seiji.aguchi@hds.com>
Acked-by: Mike Waychison <mikew@google.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
2012-11-26 16:08:37 -08:00
Seiji Aguchi 0f7de85a94 efi_pstore: Add a format check for an existing variable name at reading time
[Issue]

a format of variable name has been updated to type, id, count and ctime
to support holding multiple logs.

Format of current variable name
  dump-type0-1-2-12345678

  type:0
  id:1
  count:2
  ctime:12345678

On the other hand, if an old variable name before being updated
remains, users can't read it via /dev/pstore.

Format of old variable name
  dump-type0-1-12345678

  type:0
  id:1
  ctime:12345678

[Solution]

This patch add a format check for the old variable name in a read callback
to make it readable.

Signed-off-by: Seiji Aguchi <seiji.aguchi@hds.com>
Acked-by: Mike Waychison <mikew@google.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
2012-11-26 16:08:30 -08:00
Seiji Aguchi 755d4fe465 efi_pstore: Add a sequence counter to a variable name
[Issue]

Currently, a variable name, which identifies each entry, consists of type, id and ctime.
But if multiple events happens in a short time, a second/third event may fail to log because
efi_pstore can't distinguish each event with current variable name.

[Solution]

A reasonable way to identify all events precisely is introducing a sequence counter to
the variable name.

The sequence counter has already supported in a pstore layer with "oopscount".
So, this patch adds it to a variable name.
Also, it is passed to read/erase callbacks of platform drivers in accordance with
the modification of the variable name.

  <before applying this patch>
 a variable name of first event: dump-type0-1-12345678
 a variable name of second event: dump-type0-1-12345678

  type:0
  id:1
  ctime:12345678

 If multiple events happen in a short time, efi_pstore can't distinguish them because
 variable names are same among them.

  <after applying this patch>

 it can be distinguishable by adding a sequence counter as follows.

 a variable name of first event: dump-type0-1-1-12345678
 a variable name of Second event: dump-type0-1-2-12345678

  type:0
  id:1
  sequence counter: 1(first event), 2(second event)
  ctime:12345678

In case of a write callback executed in pstore_console_write(), "0" is added to
an argument of the write callback because it just logs all kernel messages and
doesn't need to care about multiple events.

Signed-off-by: Seiji Aguchi <seiji.aguchi@hds.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Mike Waychison <mikew@google.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
2012-11-26 16:07:44 -08:00
Seiji Aguchi a9efd39cd5 efi_pstore: Add ctime to argument of erase callback
[Issue]

Currently, a variable name, which is used to identify each log entry, consists of type,
id and ctime. But an erase callback does not use ctime.

If efi_pstore supported just one log, type and id were enough.
However, in case of supporting multiple logs, it doesn't work because
it can't distinguish each entry without ctime at erasing time.

 <Example>

 As you can see below, efi_pstore can't differentiate first event from second one without ctime.

 a variable name of first event: dump-type0-1-12345678
 a variable name of second event: dump-type0-1-23456789

  type:0
  id:1
  ctime:12345678, 23456789

[Solution]

This patch adds ctime to an argument of an erase callback.

It works across reboots because ctime of pstore means the date that the record was originally stored.
To do this, efi_pstore saves the ctime to variable name at writing time and passes it to pstore
at reading time.

Signed-off-by: Seiji Aguchi <seiji.aguchi@hds.com>
Acked-by: Mike Waychison <mikew@google.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
2012-11-26 16:02:12 -08:00
Seiji Aguchi 96480d9c8f efi_pstore: Remove a logic erasing entries from a write callback to hold multiple logs
[Issue]

Currently, efi_pstore driver simply overwrites existing panic messages in NVRAM.
So, in the following scenario, we will lose 1st panic messages.

1. kernel panics.
2. efi_pstore is kicked and writes panic messages to NVRAM.
3. system reboots.
4. kernel panics again before a user checks the 1st panic messages in NVRAM.

[Solution]

A reasonable solution to fix the issue is just holding multiple logs without erasing
existing entries.
This patch removes a logic erasing existing entries in a write callback
because the logic is not needed in the write callback to support holding multiple logs.

Signed-off-by: Seiji Aguchi <seiji.aguchi@hds.com>
Acked-by: Mike Waychison <mikew@google.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
2012-11-26 16:02:04 -08:00
Seiji Aguchi dd230fecab efi_pstore: Add a logic erasing entries to an erase callback
[Issue]

Currently, efi_pstore driver simply overwrites existing panic messages in NVRAM.
So, in the following scenario, we will lose 1st panic messages.

 1. kernel panics.
 2. efi_pstore is kicked and writes panic messages to NVRAM.
 3. system reboots.
 4. kernel panics again before a user checks the 1st panic messages in NVRAM.

[Solution]

A reasonable solution to fix the issue is just holding multiple logs without erasing
existing entries.

This patch freshly adds a logic erasing existing entries, which shared with a write callback,
to an erase callback.
To support holding multiple logs, the write callback doesn't need to erase any entries and
it will be removed in a subsequent patch.

Signed-off-by: Seiji Aguchi <seiji.aguchi@hds.com>
Acked-by: Mike Waychison <mikew@google.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
2012-11-26 16:01:56 -08:00
Seiji Aguchi d80a361d77 efi_pstore: Check remaining space with QueryVariableInfo() before writing data
[Issue]

As discussed in a thread below, Running out of space in EFI isn't a well-tested scenario.
And we wouldn't expect all firmware to handle it gracefully.
http://marc.info/?l=linux-kernel&m=134305325801789&w=2

On the other hand, current efi_pstore doesn't check a remaining space of storage at writing time.
Therefore, efi_pstore may not work if it tries to write a large amount of data.

[Patch Description]

To avoid handling the situation above, this patch checks if there is a space enough to log with
QueryVariableInfo() before writing data.

Signed-off-by: Seiji Aguchi <seiji.aguchi@hds.com>
Acked-by: Mike Waychison <mikew@google.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
2012-11-26 16:01:46 -08:00
Matt Fleming e83af1f18c efivarfs: Make efivarfs_fill_super() static
sparse is complaining that efivarfs_fill_super() doesn't have a
prototype. Make it static to avoid the warning.

Cc: Xie ChanglongX <changlongx.xie@intel.com>
Cc: Matthew Garrett <mjg@redhat.com>
Cc: Jeremy Kerr <jeremy.kerr@canonical.com>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
2012-11-15 20:08:13 +00:00
Matt Fleming 89d16665d3 efivarfs: Use query_variable_info() to limit kmalloc()
We don't want someone who can write EFI variables to be able to
allocate arbitrarily large amounts of memory, so cap it to something
sensible like the amount of free space for EFI variables.

Acked-by: Jeremy Kerr <jeremy.kerr@canonical.com>
Cc: Matthew Garrett <mjg@redhat.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
2012-11-13 12:33:21 +00:00
Matt Fleming cfcf2f1170 efivarfs: Fix return value of efivarfs_file_write()
We're stuffing a variable of type size_t (unsigned) into a ssize_t
(signed) which, even though both types should be the same number of
bits, it's just asking for sign issues to be introduced.

Cc: Jeremy Kerr <jeremy.kerr@canonical.com>
Reported-by: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
2012-10-30 10:39:28 +00:00
Matt Fleming aeeaa8d46a efivarfs: Return a consistent error when efivarfs_get_inode() fails
Instead of returning -ENOSPC if efivarfs_get_inode() fails we should
be returning -ENOMEM, since running out of memory is the only reason
it can fail.  Furthermore, that's the error value used everywhere else
in this file. It's also less likely to confuse users that hit this
error case.

Acked-by: Jeremy Kerr <jeremy.kerr@canonical.com>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
2012-10-30 10:39:28 +00:00
Matt Fleming 07b1c5bc64 efivarfs: Make 'datasize' unsigned long
There's no reason to declare 'datasize' as an int, since the majority
of the functions it's passed to expect an unsigned long anyway. Plus,
this way we avoid any sign problems during arithmetic.

Acked-by: Jeremy Kerr <jeremy.kerr@canonical.com>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
2012-10-30 10:39:27 +00:00
Matt Fleming 91716322d8 efivarfs: Add unique magic number
Using pstore's superblock magic number is no doubt going to cause
problems in the future. Give efivarfs its own magic number.

Acked-by: Jeremy Kerr <jeremy.kerr@canonical.com>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
2012-10-30 10:39:27 +00:00
Matt Fleming d292384152 efivarfs: Replace magic number with sizeof(attributes)
Seeing "+ 4" littered throughout the functions gets a bit
confusing. Use "sizeof(attributes)" which clearly explains what
quantity we're adding.

Acked-by: Jeremy Kerr <jeremy.kerr@canonical.com>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
2012-10-30 10:39:26 +00:00
Matt Fleming 7253eaba7b efivarfs: Return an error if we fail to read a variable
Instead of always returning 0 in efivarfs_file_read(), even when we
fail to successfully read the variable, convert the EFI status to
something meaningful and return that to the caller. This way the user
will have some hint as to why the read failed.

Acked-by: Jeremy Kerr <jeremy.kerr@canonical.com>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
2012-10-30 10:39:25 +00:00
Jeremy Kerr 310ad75448 efi: Clarify GUID length calculations
At present, the handling of GUIDs in efivar file names isn't consistent.
We use GUID_LEN in some places, and 38 in others (GUID_LEN plus
separator), and implicitly use the presence of the trailing NUL.

This change removes the trailing NUL from GUID_LEN, so that we're
explicitly adding it when required. We also replace magic numbers
with GUID_LEN, and clarify the comments where appropriate.

We also fix the allocation size in efivar_create_sysfs_entry, where
we're allocating one byte too much, due to counting the trailing NUL
twice - once when calculating short_name_size, and once in the kzalloc.

Signed-off-by: Jeremy Kerr <jeremy.kerr@canonical.com>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
2012-10-30 10:39:25 +00:00
Jeremy Kerr f5f6a60ad5 efivarfs: Implement exclusive access for {get,set}_variable
Currently, efivarfs does not enforce exclusion over the get_variable and
set_variable operations. Section 7.1 of UEFI requires us to only allow a
single processor to enter {get,set}_variable services at once.

This change acquires the efivars->lock over calls to these operations
from the efivarfs paths.

Signed-off-by: Jeremy Kerr <jeremy.kerr@canonical.com>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
2012-10-30 10:39:24 +00:00
Andy Whitcroft 5ba6e2919b efivarfs: efivarfs_fill_super() ensure we clean up correctly on error
Ensure we free both the name and inode on error when building the
individual variables.

Signed-off-by: Andy Whitcroft <apw@canonical.com>
Acked-by: Matthew Garrett <mjg@redhat.com>
Acked-by: Jeremy Kerr <jeremy.kerr@canonical.com>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
2012-10-30 10:39:23 +00:00
Andy Whitcroft c0359db1a1 efivarfs: efivarfs_fill_super() ensure we free our temporary name
d_alloc_name() copies the passed name to new storage, once complete we
no longer need our name.

Signed-off-by: Andy Whitcroft <apw@canonical.com>
Acked-by: Matthew Garrett <mjg@redhat.com>
Acked-by: Jeremy Kerr <jeremy.kerr@canonical.com>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
2012-10-30 10:39:23 +00:00
Andy Whitcroft 5c9b50ab8c efivarfs: efivarfs_fill_super() fix inode reference counts
When d_make_root() fails it will automatically drop the reference
on the root inode.  We should not be doing so as well.

Signed-off-by: Andy Whitcroft <apw@canonical.com>
Acked-by: Matthew Garrett <mjg@redhat.com>
Acked-by: Jeremy Kerr <jeremy.kerr@canonical.com>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
2012-10-30 10:39:22 +00:00
Andy Whitcroft 45a937a883 efivarfs: efivarfs_create() ensure we drop our reference on inode on error
Signed-off-by: Andy Whitcroft <apw@canonical.com>
Acked-by: Matthew Garrett <mjg@redhat.com>
Acked-by: Jeremy Kerr <jeremy.kerr@canonical.com>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
2012-10-30 10:39:22 +00:00
Andy Whitcroft d142df03a7 efivarfs: efivarfs_file_read ensure we free data in error paths
Signed-off-by: Andy Whitcroft <apw@canonical.com>
Acked-by: Matthew Garrett <mjg@redhat.com>
Acked-by: Jeremy Kerr <jeremy.kerr@canonical.com>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
2012-10-30 10:39:21 +00:00
Lee, Chun-Yi 605e70c7aa 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.

Cc: Matthew Garrett <mjg@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Lee, Chun-Yi <jlee@suse.com>
Signed-off-by: Jeremy Kerr <jeremy.kerr@canonical.com>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
2012-10-30 10:39:18 +00:00
Jeremy Kerr 0c542edde3 efi: Handle deletions and size changes in efivarfs_write_file
A write to an efivarfs file will not always result in a variable of
'count' size after the EFI SetVariable() call. We may have appended to
the existing data (ie, with the EFI_VARIABLE_APPEND_WRITE attribute), or
even have deleted the variable (with an authenticated variable update,
with a zero datasize).

This change re-reads the updated variable from firmware, to check for
size changes and deletions. In the latter case, we need to drop the
dentry.

Signed-off-by: Jeremy Kerr <jeremy.kerr@canonical.com>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
2012-10-30 10:39:17 +00:00
Matthew Garrett 5d9db88376 efi: Add support for a UEFI variable filesystem
The existing EFI variables code only supports 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. So,
instead, let's add a filesystem. Variables can be read, written and
created, with the first 4 bytes of each variable representing its UEFI
attributes. The create() method doesn't actually commit to flash since
zero-length variables can't exist per-spec.

Updates from Jeremy Kerr <jeremy.kerr@canonical.com>.

Signed-off-by: Matthew Garrett <mjg@redhat.com>
Signed-off-by: Jeremy Kerr <jeremy.kerr@canonical.com>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
2012-10-30 10:39:16 +00:00
Khalid Aziz 7083909023 firmware: Add missing attributes to EFI variable attribute print out from sysfs
Some of the EFI variable attributes are missing from print out from
/sys/firmware/efi/vars/*/attributes. This patch adds those in. It also
updates code to use pre-defined constants for masking current value
of attributes.

Signed-off-by: Khalid Aziz <khalid.aziz@hp.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Matthew Garrett <mjg@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-09-10 16:40:30 -07:00
Matthew Garrett 54b3a4d311 efivars: Improve variable validation
Ben Hutchings pointed out that the validation in efivars was inadequate -
most obviously, an entry with size 0 would server as a DoS against the
kernel. Improve this based on his suggestions.

Signed-off-by: Matthew Garrett <mjg@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-05-03 17:19:19 -07:00
Matthew Garrett fec6c20b57 efi: Validate UEFI boot variables
A common flaw in UEFI systems is a refusal to POST triggered by a malformed
boot variable. Once in this state, machines may only be restored by
reflashing their firmware with an external hardware device. While this is
obviously a firmware bug, the serious nature of the outcome suggests that
operating systems should filter their variable writes in order to prevent
a malicious user from rendering the machine unusable.

Signed-off-by: Matthew Garrett <mjg@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-04-30 15:30:18 -07:00
Linus Torvalds 6ed23fd6c0 Merge branch 'pstore' of git://git.kernel.org/pub/scm/linux/kernel/git/aegl/linux
* 'pstore' of git://git.kernel.org/pub/scm/linux/kernel/git/aegl/linux:
  pstore: gracefully handle NULL pstore_info functions
  pstore: pass reason to backend write callback
2012-01-06 18:03:02 -08:00
Christoph Fritz eee628da2e efivars: add missing parameter to efi_pstore_read()
In the case where CONFIG_PSTORE=n, the function efi_pstore_read() doesn't
have the correct list of parameters. This patch provides a definition
of efi_pstore_read() with 'char **buf' added to fix this warning:
"drivers/firmware/efivars.c:609: warning: initialization from".

problem introduced in commit f6f8285132

Signed-off-by: Christoph Fritz <chf.fritz@googlemail.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
2011-11-28 15:33:32 -08:00
Kees Cook 3d6d8d20ec pstore: pass reason to backend write callback
This allows a backend to filter on the dmesg reason as well as the pstore
reason. When ramoops is switched to pstore, this is needed since it has
no interest in storing non-crash dmesg details.

Drop pstore_write() as it has no users, and handling the "reason" here
has no obviously correct value.

Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Tony Luck <tony.luck@intel.com>
2011-11-17 13:13:29 -08:00
Kees Cook f6f8285132 pstore: pass allocated memory region back to caller
The buf_lock cannot be held while populating the inodes, so make the backend
pass forward an allocated and filled buffer instead. This solves the following
backtrace. The effect is that "buf" is only ever used to notify the backends
that something was written to it, and shouldn't be used in the read path.

To replace the buf_lock during the read path, isolate the open/read/close
loop with a separate mutex to maintain serialized access to the backend.

Note that is is up to the pstore backend to cope if the (*write)() path is
called in the middle of the read path.

[   59.691019] BUG: sleeping function called from invalid context at .../mm/slub.c:847
[   59.691019] in_atomic(): 0, irqs_disabled(): 1, pid: 1819, name: mount
[   59.691019] Pid: 1819, comm: mount Not tainted 3.0.8 #1
[   59.691019] Call Trace:
[   59.691019]  [<810252d5>] __might_sleep+0xc3/0xca
[   59.691019]  [<810a26e6>] kmem_cache_alloc+0x32/0xf3
[   59.691019]  [<810b53ac>] ? __d_lookup_rcu+0x6f/0xf4
[   59.691019]  [<810b68b1>] alloc_inode+0x2a/0x64
[   59.691019]  [<810b6903>] new_inode+0x18/0x43
[   59.691019]  [<81142447>] pstore_get_inode.isra.1+0x11/0x98
[   59.691019]  [<81142623>] pstore_mkfile+0xae/0x26f
[   59.691019]  [<810a2a66>] ? kmem_cache_free+0x19/0xb1
[   59.691019]  [<8116c821>] ? ida_get_new_above+0x140/0x158
[   59.691019]  [<811708ea>] ? __init_rwsem+0x1e/0x2c
[   59.691019]  [<810b67e8>] ? inode_init_always+0x111/0x1b0
[   59.691019]  [<8102127e>] ? should_resched+0xd/0x27
[   59.691019]  [<8137977f>] ? _cond_resched+0xd/0x21
[   59.691019]  [<81142abf>] pstore_get_records+0x52/0xa7
[   59.691019]  [<8114254b>] pstore_fill_super+0x7d/0x91
[   59.691019]  [<810a7ff5>] mount_single+0x46/0x82
[   59.691019]  [<8114231a>] pstore_mount+0x15/0x17
[   59.691019]  [<811424ce>] ? pstore_get_inode.isra.1+0x98/0x98
[   59.691019]  [<810a8199>] mount_fs+0x5a/0x12d
[   59.691019]  [<810b9174>] ? alloc_vfsmnt+0xa4/0x14a
[   59.691019]  [<810b9474>] vfs_kern_mount+0x4f/0x7d
[   59.691019]  [<810b9d7e>] do_kern_mount+0x34/0xb2
[   59.691019]  [<810bb15f>] do_mount+0x5fc/0x64a
[   59.691019]  [<810912fb>] ? strndup_user+0x2e/0x3f
[   59.691019]  [<810bb3cb>] sys_mount+0x66/0x99
[   59.691019]  [<8137b537>] sysenter_do_call+0x12/0x26

Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Tony Luck <tony.luck@intel.com>
2011-11-17 12:58:07 -08:00
Chen Gong b238b8fa93 pstore: make pstore write function return normal success/fail value
Currently pstore write interface employs record id as return
value, but it is not enough because it can't tell caller if
the write operation is successful. Pass the record id back via
an argument pointer and return zero for success, non-zero for
failure.

Signed-off-by: Chen Gong <gong.chen@linux.intel.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
2011-10-12 09:17:24 -07:00
Don Zickus abd4d5587b pstore: change mutex locking to spin_locks
pstore was using mutex locking to protect read/write access to the
backend plug-ins.  This causes problems when pstore is executed in
an NMI context through panic() -> kmsg_dump().

This patch changes the mutex to a spin_lock_irqsave then also checks to
see if we are in an NMI context.  If we are in an NMI and can't get the
lock, just print a message stating that and blow by the locking.

All this is probably a hack around the bigger locking problem but it
solves my current situation of trying to sleep in an NMI context.

Tested by loading the lkdtm module and executing a HARDLOCKUP which
will cause the machine to panic inside the nmi handler.

Signed-off-by: Don Zickus <dzickus@redhat.com>
Acked-by: Matthew Garrett <mjg@redhat.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
2011-08-16 11:55:58 -07:00
Tony Luck b728a5c806 efivars: fix warnings when CONFIG_PSTORE=n
drivers/firmware/efivars.c:161: warning: ‘utf16_strlen’ defined but not used
utf16_strlen() is only used inside CONFIG_PSTORE - make this "static inline"
to shut the compiler up [thanks to hpa for the suggestion].

drivers/firmware/efivars.c:602: warning: initialization from incompatible pointer type
Between v1 and v2 of this patch series we decided to make the "part" number
unsigned - but missed fixing the stub version of efi_pstore_write()

Acked-by: Matthew Garrett <mjg@redhat.com>
Acked-by: Mike Waychison <mikew@google.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
2011-08-02 15:08:30 -07:00
Mike Waychison 7644c16c7e efivars: Introduce PSTORE_EFI_ATTRIBUTES
Consolidate the attributes listed for pstore operations in one place,
PSTORE_EFI_ATTRIBUTES.

Signed-off-by: Mike Waychison <mikew@google.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
2011-07-22 16:15:49 -07:00
Mike Waychison c475594d83 efivars: Use string functions in pstore_write
Instead of open-coding the string operations for comparing the prefix of
the variable names, use the provided utf16_* string functions.

This patch also changes the calls to efi.set_variable to
efivars->ops->set_variable so that the right function gets called in the
case of gsmi (which doesn't have a valid efi structure).

As well, make sure that we only consider variables with the right vendor
string.

Signed-off-by: Mike Waychison <mikew@google.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
2011-07-22 16:15:40 -07:00
Mike Waychison 828aa1f00e efivars: introduce utf16_strncmp
Introduce utf16_strncmp which is used in the next patch.  Semantics
should be the same as the strncmp C function.

Signed-off-by: Mike Waychison <mikew@google.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
2011-07-22 16:15:31 -07:00
Mike Waychison a294090839 efivars: String functions
Fix the string functions in the efivars driver to be called utf16_*
instead of utf8_* as the encoding is utf16, not utf8.

As well, rename utf16_strlen to utf16_strnlen as it takes a maxlength
argument and the name should be consistent with the standard C function
names.  utf16_strlen is still provided for convenience in a subsequent
patch.

Signed-off-by: Mike Waychison <mikew@google.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
2011-07-22 16:15:21 -07:00
Matthew Garrett 5ee9c198a4 efi: Add support for using efivars as a pstore backend
EFI provides an area of nonvolatile storage managed by the firmware. We
can use this as a pstore backend to maintain copies of oopses, aiding
diagnosis.

Signed-off-by: Matthew Garrett <mjg@redhat.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
2011-07-22 16:15:04 -07:00
Linus Torvalds 57d19e80f4 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: (39 commits)
  b43: fix comment typo reqest -> request
  Haavard Skinnemoen has left Atmel
  cris: typo in mach-fs Makefile
  Kconfig: fix copy/paste-ism for dell-wmi-aio driver
  doc: timers-howto: fix a typo ("unsgined")
  perf: Only include annotate.h once in tools/perf/util/ui/browsers/annotate.c
  md, raid5: Fix spelling error in comment ('Ofcourse' --> 'Of course').
  treewide: fix a few typos in comments
  regulator: change debug statement be consistent with the style of the rest
  Revert "arm: mach-u300/gpio: Fix mem_region resource size miscalculations"
  audit: acquire creds selectively to reduce atomic op overhead
  rtlwifi: don't touch with treewide double semicolon removal
  treewide: cleanup continuations and remove logging message whitespace
  ath9k_hw: don't touch with treewide double semicolon removal
  include/linux/leds-regulator.h: fix syntax in example code
  tty: fix typo in descripton of tty_termios_encode_baud_rate
  xtensa: remove obsolete BKL kernel option from defconfig
  m68k: fix comment typo 'occcured'
  arch:Kconfig.locks Remove unused config option.
  treewide: remove extra semicolons
  ...
2011-05-23 09:12:26 -07:00
Justin P. Mattock 70f23fd66b treewide: fix a few typos in comments
- kenrel -> kernel
- whetehr -> whether
- ttt -> tt
- sss -> ss

Signed-off-by: Justin P. Mattock <justinmattock@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2011-05-10 10:16:21 +02:00
Randy Dunlap aabb6e1531 efivars: prevent oops on unload when efi is not enabled
efivars_exit() should check for efi_enabled and not undo
allocations when efi is not enabled.  Otherwise there is an Oops
during module unload:

calling  efivars_init+0x0/0x1000 [efivars] @ 2810
EFI Variables Facility v0.08 2004-May-17
initcall efivars_init+0x0/0x1000 [efivars] returned 0 after 5120 usecs
Oops: 0000 [#1] SMP DEBUG_PAGEALLOC
last sysfs file: /sys/module/firmware_class/initstate
CPU 1
Modules linked in: efivars(-) af_packet tun nfsd lockd nfs_acl auth_rpcgss sunrpc ipt_REJECT nf_conntrack_ipv4 nf_defrag_ipv4 iptable_filter ip_tables ip6t_REJECT xt_tcpudp nf_conntrack_ipv6 nf_defrag_ipv6 xt_state nf_conntrack ip6table_filter ip6_tables x_tables ipv6 cpufreq_ondemand acpi_cpufreq freq_table mperf binfmt_misc dm_mirror dm_region_hash dm_log dm_multipath scsi_dh dm_mod snd_hda_codec_analog snd_hda_intel snd_hda_codec snd_hwdep mousedev snd_seq joydev snd_seq_device mac_hid evdev snd_pcm usbkbd usbmouse usbhid snd_timer hid tg3 snd sr_mod pcspkr rtc_cmos soundcore cdrom iTCO_wdt processor sg dcdbas i2c_i801 rtc_core iTCO_vendor_support intel_agp snd_page_alloc thermal_sys rtc_lib intel_gtt 8250_pnp button hwmon unix ide_pci_generic ide_core ata_generic pata_acpi ata_piix sd_mod crc_t10dif ext3 jbd mbcache uhci_hcd ohci_hcd ssb mmc_core pcmcia pcmcia_core firmware_class ehci_hcd usbcore [last unloaded: dell_rbu]

Pid: 2812, comm: rmmod Not tainted 2.6.39-rc6 #1 Dell Inc.                 OptiPlex 745                 /0TY565
RIP: 0010:[<ffffffffa06a17f6>]  [<ffffffffa06a17f6>] unregister_efivars+0x28/0x12c [efivars]
RSP: 0018:ffff88005eedde98  EFLAGS: 00010283
RAX: ffffffffa06a23fc RBX: ffffffffa06a44c0 RCX: ffff88007c227a50
RDX: 0000000000000000 RSI: 00000055ac13db78 RDI: ffffffffa06a44c0
RBP: ffff88005eeddec8 R08: 0000000000000000 R09: ffff88005eeddd78
R10: ffffffffa06a4220 R11: ffff88005eeddd78 R12: fffffffffffff7d0
R13: 00007fff5a3aaec0 R14: 0000000000000000 R15: ffffffffa06a4508
FS:  00007fa8dcc4a6f0(0000) GS:ffff88007c200000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
CR2: 0000000000000000 CR3: 000000005d148000 CR4: 00000000000006e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Process rmmod (pid: 2812, threadinfo ffff88005eedc000, task ffff88006754b000)
Stack:
 ffff88005eeddec8 ffffffffa06a4220 0000000000000000 00007fff5a3aaec0
 0000000000000000 0000000000000001 ffff88005eedded8 ffffffffa06a2418
 ffff88005eeddf78 ffffffff810d3598 ffffffffa06a4220 0000000000000880
Call Trace:
 [<ffffffffa06a2418>] efivars_exit+0x1c/0xc04 [efivars]
 [<ffffffff810d3598>] sys_delete_module+0x2d6/0x368
 [<ffffffff812d1db9>] ? lockdep_sys_exit_thunk+0x35/0x67
 [<ffffffff810fcba1>] ? audit_syscall_entry+0x172/0x1a5
 [<ffffffff81575082>] system_call_fastpath+0x16/0x1b
Code: 5c c9 c3 55 48 89 e5 41 57 41 56 41 55 41 54 53 48 83 ec 08 0f 1f 44 00 00 4c 8b 67 48 48 89 fb 4c 8d 7f 48 49 81 ec 30 08 00 00 <4d> 8b ac 24 30 08 00 00 49 81 ed 30 08 00 00 eb 59 48 89 df 48
RIP  [<ffffffffa06a17f6>] unregister_efivars+0x28/0x12c [efivars]
 RSP <ffff88005eedde98>
CR2: 0000000000000000
 ---[ end trace aa99b99090f70baa ]---

Matt apparently removed such a check in 2004 (with no reason given):
 *  17 May 2004 - Matt Domsch <Matt_Domsch@dell.com>
 *   remove check for efi_enabled in exit
but there have been several changes since then.

Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Mike Waychison <mikew@google.com>
Tested-by: Randy Dunlap <randy.dunlap@oracle.com>
Cc: Matt Domsch <Matt_Domsch@dell.com>
Cc: <matthew.e.tolentino@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-05-06 17:52:32 -07:00