Commit ed9dc8ce authored by Seth Forshee's avatar Seth Forshee Committed by Matt Fleming
Browse files

efivars: Allow disabling use as a pstore backend 



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: default avatarSeth 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: default avatarMatt Fleming <matt.fleming@intel.com>
parent f6161aa1

drivers/firmware/Kconfig

+9 −0
Original line number Diff line number Diff line
@@ -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

drivers/firmware/efivars.c

+20 −44
Original line number Diff line number Diff line
@@ -1309,9 +1309,7 @@ static const struct inode_operations efivarfs_dir_inode_operations = { 
	.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)

{
@@ -1514,38 +1512,6 @@ static int efi_pstore_erase(enum pstore_type_id type, u64 id, int count, 


	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,
@@ -1557,6 +1523,24 @@ static struct pstore_info efi_pstore_info = { 
	.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)
@@ -2025,15 +2009,7 @@ int register_efivars(struct efivars *efivars, 
	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);

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