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path: root/drivers/firmware/efi/vars.c
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2014-09-18Merge tag 'v3.10.55' into linux-linaro-lsklsk-v3.10-14.09Mark Brown
This is the 3.10.55 stable release
2014-09-17firmware: Do not use WARN_ON(!spin_is_locked())Guenter Roeck
commit aee530cfecf4f3ec83b78406bac618cec35853f8 upstream. spin_is_locked() always returns false for uniprocessor configurations in several architectures, so do not use WARN_ON with it. Use lockdep_assert_held() instead to also reduce overhead in non-debug kernels. Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Matt Fleming <matt.fleming@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-07-23efivars: Stop passing a struct argument to efivar_validate()Matt Fleming
In preparation for compat support, we can't assume that user variable object is represented by a 'struct efi_variable'. Convert the validation functions to take the variable name as an argument, which is the only piece of the struct that was ever used anyway. Cc: Mike Waychison <mikew@google.com> Signed-off-by: Matt Fleming <matt.fleming@intel.com> (cherry picked from commit a5d92ad32dad94fd8f3f61778561d532bb3a2f77) Signed-off-by: Mark Brown <broonie@linaro.org>
2014-07-23efivars, efi-pstore: Hold off deletion of sysfs entry until the scan is ↵Seiji Aguchi
completed Currently, when mounting pstore file system, a read callback of efi_pstore driver runs mutiple times as below. - In the first read callback, scan efivar_sysfs_list from head and pass a kmsg buffer of a entry to an upper pstore layer. - In the second read callback, rescan efivar_sysfs_list from the entry and pass another kmsg buffer to it. - Repeat the scan and pass until the end of efivar_sysfs_list. In this process, an entry is read across the multiple read function calls. To avoid race between the read and erasion, the whole process above is protected by a spinlock, holding in open() and releasing in close(). At the same time, kmemdup() is called to pass the buffer to pstore filesystem during it. And then, it causes a following lockdep warning. To make the dynamic memory allocation runnable without taking spinlock, holding off a deletion of sysfs entry if it happens while scanning it via efi_pstore, and deleting it after the scan is completed. To implement it, this patch introduces two flags, scanning and deleting, to efivar_entry. On the code basis, it seems that all the scanning and deleting logic is not needed because __efivars->lock are not dropped when reading from the EFI variable store. But, the scanning and deleting logic is still needed because an efi-pstore and a pstore filesystem works as follows. In case an entry(A) is found, the pointer is saved to psi->data. And efi_pstore_read() passes the entry(A) to a pstore filesystem by releasing __efivars->lock. And then, the pstore filesystem calls efi_pstore_read() again and the same entry(A), which is saved to psi->data, is used for resuming to scan a sysfs-list. So, to protect the entry(A), the logic is needed. [ 1.143710] ------------[ cut here ]------------ [ 1.144058] WARNING: CPU: 1 PID: 1 at kernel/lockdep.c:2740 lockdep_trace_alloc+0x104/0x110() [ 1.144058] DEBUG_LOCKS_WARN_ON(irqs_disabled_flags(flags)) [ 1.144058] Modules linked in: [ 1.144058] CPU: 1 PID: 1 Comm: systemd Not tainted 3.11.0-rc5 #2 [ 1.144058] 0000000000000009 ffff8800797e9ae0 ffffffff816614a5 ffff8800797e9b28 [ 1.144058] ffff8800797e9b18 ffffffff8105510d 0000000000000080 0000000000000046 [ 1.144058] 00000000000000d0 00000000000003af ffffffff81ccd0c0 ffff8800797e9b78 [ 1.144058] Call Trace: [ 1.144058] [<ffffffff816614a5>] dump_stack+0x54/0x74 [ 1.144058] [<ffffffff8105510d>] warn_slowpath_common+0x7d/0xa0 [ 1.144058] [<ffffffff8105517c>] warn_slowpath_fmt+0x4c/0x50 [ 1.144058] [<ffffffff8131290f>] ? vsscanf+0x57f/0x7b0 [ 1.144058] [<ffffffff810bbd74>] lockdep_trace_alloc+0x104/0x110 [ 1.144058] [<ffffffff81192da0>] __kmalloc_track_caller+0x50/0x280 [ 1.144058] [<ffffffff815147bb>] ? efi_pstore_read_func.part.1+0x12b/0x170 [ 1.144058] [<ffffffff8115b260>] kmemdup+0x20/0x50 [ 1.144058] [<ffffffff815147bb>] efi_pstore_read_func.part.1+0x12b/0x170 [ 1.144058] [<ffffffff81514800>] ? efi_pstore_read_func.part.1+0x170/0x170 [ 1.144058] [<ffffffff815148b4>] efi_pstore_read_func+0xb4/0xe0 [ 1.144058] [<ffffffff81512b7b>] __efivar_entry_iter+0xfb/0x120 [ 1.144058] [<ffffffff8151428f>] efi_pstore_read+0x3f/0x50 [ 1.144058] [<ffffffff8128d7ba>] pstore_get_records+0x9a/0x150 [ 1.158207] [<ffffffff812af25c>] ? selinux_d_instantiate+0x1c/0x20 [ 1.158207] [<ffffffff8128ce30>] ? parse_options+0x80/0x80 [ 1.158207] [<ffffffff8128ced5>] pstore_fill_super+0xa5/0xc0 [ 1.158207] [<ffffffff811ae7d2>] mount_single+0xa2/0xd0 [ 1.158207] [<ffffffff8128ccf8>] pstore_mount+0x18/0x20 [ 1.158207] [<ffffffff811ae8b9>] mount_fs+0x39/0x1b0 [ 1.158207] [<ffffffff81160550>] ? __alloc_percpu+0x10/0x20 [ 1.158207] [<ffffffff811c9493>] vfs_kern_mount+0x63/0xf0 [ 1.158207] [<ffffffff811cbb0e>] do_mount+0x23e/0xa20 [ 1.158207] [<ffffffff8115b51b>] ? strndup_user+0x4b/0xf0 [ 1.158207] [<ffffffff811cc373>] SyS_mount+0x83/0xc0 [ 1.158207] [<ffffffff81673cc2>] system_call_fastpath+0x16/0x1b [ 1.158207] ---[ end trace 61981bc62de9f6f4 ]--- Signed-off-by: Seiji Aguchi <seiji.aguchi@hds.com> Tested-by: Madper Xie <cxie@redhat.com> Cc: stable@kernel.org Signed-off-by: Matt Fleming <matt.fleming@intel.com> (cherry picked from commit e0d59733f6b1796b8d6692642c87d7dd862c3e3a) Signed-off-by: Mark Brown <broonie@linaro.org>
2013-04-30efi: locking fix in efivar_entry_set_safe()Dan Carpenter
The intent is that if we aren't allowed to block because we're in an NMI or an emergency then we only take the lock if it is uncontended. Part of the problem is the test is reversed so we return -EBUSY if we acquire the lock. Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Matt Fleming <matt.fleming@intel.com>
2013-04-30efi, pstore: Read data from variable store before memcpy()Matt Fleming
Seiji reported getting empty dmesg-* files, because the data was never actually read in efi_pstore_read_func(), and so the memcpy() was copying garbage data. This patch necessitated adding __efivar_entry_get() which is callable between efivar_entry_iter_{begin,end}(). We can also delete __efivar_entry_size() because efi_pstore_read_func() was the only caller. Reported-by: Seiji Aguchi <seiji.aguchi@hds.com> Tested-by: Seiji Aguchi <seiji.aguchi@hds.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Matthew Garrett <matthew.garrett@nebula.com> Signed-off-by: Matt Fleming <matt.fleming@intel.com>
2013-04-30Merge tag 'v3.9' into efi-for-tip2Matt Fleming
Resolve conflicts for Ingo. Conflicts: drivers/firmware/Kconfig drivers/firmware/efivars.c Signed-off-by: Matt Fleming <matt.fleming@intel.com>
2013-04-17efi: split efisubsystem from efivarsTom Gundersen
This registers /sys/firmware/efi/{,systab,efivars/} whenever EFI is enabled and the system is booted with EFI. This allows *) userspace to check for the existence of /sys/firmware/efi as a way to determine whether or it is running on an EFI system. *) 'mount -t efivarfs none /sys/firmware/efi/efivars' without manually loading any modules. [ Also, move the efivar API into vars.c and unconditionally compile it. This allows us to move efivars.c, which now only contains the sysfs variable code, into the firmware/efi directory. Note that the efivars.c filename is kept to maintain backwards compatability with the old efivars.ko module. With this patch it is now possible for efivarfs to be built without CONFIG_EFI_VARS - Matt ] Cc: Seiji Aguchi <seiji.aguchi@hds.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Mike Waychison <mikew@google.com> Cc: Kay Sievers <kay@vrfy.org> Cc: Jeremy Kerr <jk@ozlabs.org> Cc: Matthew Garrett <mjg59@srcf.ucam.org> Cc: Chun-Yi Lee <jlee@suse.com> Cc: Andy Whitcroft <apw@canonical.com> Cc: Tobias Powalowski <tpowa@archlinux.org> Signed-off-by: Tom Gundersen <teg@jklm.no> Signed-off-by: Matt Fleming <matt.fleming@intel.com>