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authorSeth Forshee <seth.forshee@canonical.com>2013-03-11 22:17:50 +0100
committerMatt Fleming <matt.fleming@intel.com>2013-03-21 13:43:46 +0100
commitec0971ba5372a4dfa753f232449d23a8fd98490e (patch)
tree1c364f3e1fbbd75a413edc80c1c237e210e997c0 /drivers/firmware/efivars.c
parentefivars: Allow disabling use as a pstore backend (diff)
downloadlinux-ec0971ba5372a4dfa753f232449d23a8fd98490e.tar.xz
linux-ec0971ba5372a4dfa753f232449d23a8fd98490e.zip
efivars: Add module parameter to disable use as a pstore backend
We know that with some firmware implementations writing too much data to UEFI variables can lead to bricking machines. Recent changes attempt to address this issue, but for some it may still be prudent to avoid writing large amounts of data until the solution has been proven on a wide variety of hardware. Crash dumps or other data from pstore can potentially be a large data source. Add a pstore_module parameter to efivars to allow disabling its use as a backend for pstore. Also add a config option, CONFIG_EFI_VARS_PSTORE_DEFAULT_DISABLE, to allow setting the default value of this paramter to true (i.e. disabled by default). Signed-off-by: Seth Forshee <seth.forshee@canonical.com> Cc: Josh Boyer <jwboyer@redhat.com> Cc: Matthew Garrett <mjg59@srcf.ucam.org> Cc: Seiji Aguchi <seiji.aguchi@hds.com> Cc: Tony Luck <tony.luck@intel.com> Cc: <stable@vger.kernel.org> Signed-off-by: Matt Fleming <matt.fleming@intel.com>
Diffstat (limited to 'drivers/firmware/efivars.c')
-rw-r--r--drivers/firmware/efivars.c8
1 files changed, 7 insertions, 1 deletions
diff --git a/drivers/firmware/efivars.c b/drivers/firmware/efivars.c
index 37b6f247399e..6607daf5a08d 100644
--- a/drivers/firmware/efivars.c
+++ b/drivers/firmware/efivars.c
@@ -103,6 +103,11 @@ MODULE_VERSION(EFIVARS_VERSION);
*/
#define GUID_LEN 36
+static bool efivars_pstore_disable =
+ IS_ENABLED(EFI_VARS_PSTORE_DEFAULT_DISABLE);
+
+module_param_named(pstore_disable, efivars_pstore_disable, bool, 0644);
+
/*
* The maximum size of VariableName + Data = 1024
* Therefore, it's reasonable to save that much
@@ -2009,7 +2014,8 @@ int register_efivars(struct efivars *efivars,
if (error)
unregister_efivars(efivars);
- efivar_pstore_register(efivars);
+ if (!efivars_pstore_disable)
+ efivar_pstore_register(efivars);
register_filesystem(&efivarfs_type);