[ 89/98] efivars: Allow disabling use as a pstore backend

Greg Kroah-Hartman
2013-03-26T23:28:24Z

From: Seth Forshee <seth.forshee@canonical.com>

commit ed9dc8ce7a1c8115dba9483a9b51df8b63a2e0ef upstream.

Add a new option, CONFIG_EFI_VARS_PSTORE, which can be set to N to
avoid using efivars as a backend to pstore, as some users may want to
compile out the code completely.

Set the default to Y to maintain backwards compatability, since this
feature has always been enabled until now.

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>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/firmware/Kconfig | 9 ++++++
drivers/firmware/efivars.c | 64 ++++++++++++++-------------------------------
2 files changed, 29 insertions(+), 44 deletions(-)

--- a/drivers/firmware/Kconfig
+++ b/drivers/firmware/Kconfig
@@ -53,6 +53,15 @@ config EFI_VARS
Subsequent efibootmgr releases may be found at:
<http://linux.dell.com/efibootmgr>

+config EFI_VARS_PSTORE
+ bool "Register efivars backend for pstore"
+ depends on EFI_VARS && PSTORE
+ default y
+ help
+ Say Y here to enable use efivars as a backend to pstore. This
+ will allow writing console messages, crash dumps, or anything
+ else supported by pstore to EFI variables.
+
config EFI_PCDP
bool "Console device selection via EFI PCDP or HCDP table"
depends on ACPI && EFI && IA64
--- a/drivers/firmware/efivars.c
+++ b/drivers/firmware/efivars.c
@@ -1301,9 +1301,7 @@ static const struct inode_operations efi
.create = efivarfs_create,
};

-static struct pstore_info efi_pstore_info;
-
-#ifdef CONFIG_PSTORE
+#ifdef CONFIG_EFI_VARS_PSTORE

static int efi_pstore_open(struct pstore_info *psi)
{
@@ -1500,38 +1498,6 @@ static int efi_pstore_erase(enum pstore_

return 0;
}
-#else
-static int efi_pstore_open(struct pstore_info *psi)
-{
- return 0;
-}
-
-static int efi_pstore_close(struct pstore_info *psi)
-{
- return 0;
-}
-
-static ssize_t efi_pstore_read(u64 *id, enum pstore_type_id *type, int *count,
- struct timespec *timespec,
- char **buf, struct pstore_info *psi)
-{
- return -1;
-}
-
-static int efi_pstore_write(enum pstore_type_id type,
- enum kmsg_dump_reason reason, u64 *id,
- unsigned int part, int count, size_t size,
- struct pstore_info *psi)
-{
- return 0;
-}
-
-static int efi_pstore_erase(enum pstore_type_id type, u64 id, int count,
- struct timespec time, struct pstore_info *psi)
-{
- return 0;
-}
-#endif

static struct pstore_info efi_pstore_info = {
.owner = THIS_MODULE,
@@ -1543,6 +1509,24 @@ static struct pstore_info efi_pstore_inf
.erase = efi_pstore_erase,
};

+static void efivar_pstore_register(struct efivars *efivars)
+{
+ efivars->efi_pstore_info = efi_pstore_info;
+ efivars->efi_pstore_info.buf = kmalloc(4096, GFP_KERNEL);
+ if (efivars->efi_pstore_info.buf) {
+ efivars->efi_pstore_info.bufsize = 1024;
+ efivars->efi_pstore_info.data = efivars;
+ spin_lock_init(&efivars->efi_pstore_info.buf_lock);
+ pstore_register(&efivars->efi_pstore_info);
+ }
+}
+#else
+static void efivar_pstore_register(struct efivars *efivars)
+{
+ return;
+}
+#endif
+
static ssize_t efivar_create(struct file *filp, struct kobject *kobj,
struct bin_attribute *bin_attr,
char *buf, loff_t pos, size_t count)
@@ -1942,15 +1926,7 @@ int register_efivars(struct efivars *efi
if (error)
unregister_efivars(efivars);

- efivars->efi_pstore_info = efi_pstore_info;
-
- efivars->efi_pstore_info.buf = kmalloc(4096, GFP_KERNEL);
- if (efivars->efi_pstore_info.buf) {
- efivars->efi_pstore_info.bufsize = 1024;
- efivars->efi_pstore_info.data = efivars;
- spin_lock_init(&efivars->efi_pstore_info.buf_lock);
- pstore_register(&efivars->efi_pstore_info);
- }
+ efivar_pstore_register(efivars);

register_filesystem(&efivarfs_type);