diff --git a/drivers/firmware/efi/efi-pstore.c b/drivers/firmware/efi/efi-pstore.c index c2f1d4e6630b..feb7fe6f2da7 100644 --- a/drivers/firmware/efi/efi-pstore.c +++ b/drivers/firmware/efi/efi-pstore.c @@ -356,10 +356,7 @@ static struct pstore_info efi_pstore_info = { static __init int efivars_pstore_init(void) { - if (!efi_rt_services_supported(EFI_RT_SUPPORTED_VARIABLE_SERVICES)) - return 0; - - if (!efivars_kobject()) + if (!efivars_kobject() || !efivar_supports_writes()) return 0; if (efivars_pstore_disable) diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c index 5114cae4ec97..fdd1db025dbf 100644 --- a/drivers/firmware/efi/efi.c +++ b/drivers/firmware/efi/efi.c @@ -176,11 +176,13 @@ static struct efivar_operations generic_ops; static int generic_ops_register(void) { generic_ops.get_variable = efi.get_variable; - generic_ops.set_variable = efi.set_variable; - generic_ops.set_variable_nonblocking = efi.set_variable_nonblocking; generic_ops.get_next_variable = efi.get_next_variable; generic_ops.query_variable_store = efi_query_variable_store; + if (efi_rt_services_supported(EFI_RT_SUPPORTED_SET_VARIABLE)) { + generic_ops.set_variable = efi.set_variable; + generic_ops.set_variable_nonblocking = efi.set_variable_nonblocking; + } return efivars_register(&generic_efivars, &generic_ops, efi_kobj); } @@ -382,7 +384,8 @@ static int __init efisubsys_init(void) return -ENOMEM; } - if (efi_rt_services_supported(EFI_RT_SUPPORTED_VARIABLE_SERVICES)) { + if (efi_rt_services_supported(EFI_RT_SUPPORTED_GET_VARIABLE | + EFI_RT_SUPPORTED_GET_NEXT_VARIABLE_NAME)) { efivar_ssdt_load(); error = generic_ops_register(); if (error) @@ -416,7 +419,8 @@ static int __init efisubsys_init(void) err_remove_group: sysfs_remove_group(efi_kobj, &efi_subsys_attr_group); err_unregister: - if (efi_rt_services_supported(EFI_RT_SUPPORTED_VARIABLE_SERVICES)) + if (efi_rt_services_supported(EFI_RT_SUPPORTED_GET_VARIABLE | + EFI_RT_SUPPORTED_GET_NEXT_VARIABLE_NAME)) generic_ops_unregister(); err_put: kobject_put(efi_kobj); diff --git a/drivers/firmware/efi/efivars.c b/drivers/firmware/efi/efivars.c index 26528a46d99e..dcea137142b3 100644 --- a/drivers/firmware/efi/efivars.c +++ b/drivers/firmware/efi/efivars.c @@ -680,11 +680,8 @@ int efivars_sysfs_init(void) struct kobject *parent_kobj = efivars_kobject(); int error = 0; - if (!efi_rt_services_supported(EFI_RT_SUPPORTED_VARIABLE_SERVICES)) - return -ENODEV; - /* No efivars has been registered yet */ - if (!parent_kobj) + if (!parent_kobj || !efivar_supports_writes()) return 0; printk(KERN_INFO "EFI Variables Facility v%s %s\n", EFIVARS_VERSION, diff --git a/drivers/firmware/efi/vars.c b/drivers/firmware/efi/vars.c index 5f2a4d162795..973eef234b36 100644 --- a/drivers/firmware/efi/vars.c +++ b/drivers/firmware/efi/vars.c @@ -1229,3 +1229,9 @@ out: return rv; } EXPORT_SYMBOL_GPL(efivars_unregister); + +int efivar_supports_writes(void) +{ + return __efivars && __efivars->ops->set_variable; +} +EXPORT_SYMBOL_GPL(efivar_supports_writes); diff --git a/fs/efivarfs/super.c b/fs/efivarfs/super.c index 12c66f5d92dd..28bb5689333a 100644 --- a/fs/efivarfs/super.c +++ b/fs/efivarfs/super.c @@ -201,6 +201,9 @@ static int efivarfs_fill_super(struct super_block *sb, struct fs_context *fc) sb->s_d_op = &efivarfs_d_ops; sb->s_time_gran = 1; + if (!efivar_supports_writes()) + sb->s_flags |= SB_RDONLY; + inode = efivarfs_get_inode(sb, NULL, S_IFDIR | 0755, 0, true); if (!inode) return -ENOMEM; @@ -252,9 +255,6 @@ static struct file_system_type efivarfs_type = { static __init int efivarfs_init(void) { - if (!efi_rt_services_supported(EFI_RT_SUPPORTED_VARIABLE_SERVICES)) - return -ENODEV; - if (!efivars_kobject()) return -ENODEV; diff --git a/include/linux/efi.h b/include/linux/efi.h index bb35f3305e55..05c47f857383 100644 --- a/include/linux/efi.h +++ b/include/linux/efi.h @@ -994,6 +994,7 @@ int efivars_register(struct efivars *efivars, int efivars_unregister(struct efivars *efivars); struct kobject *efivars_kobject(void); +int efivar_supports_writes(void); int efivar_init(int (*func)(efi_char16_t *, efi_guid_t, unsigned long, void *), void *data, bool duplicates, struct list_head *head);