diff --git a/arch/x86/platform/efi/quirks.c b/arch/x86/platform/efi/quirks.c index b0b848d6933af..f0cc00032751d 100644 --- a/arch/x86/platform/efi/quirks.c +++ b/arch/x86/platform/efi/quirks.c @@ -114,6 +114,14 @@ void efi_delete_dummy_variable(void) EFI_VARIABLE_RUNTIME_ACCESS, 0, NULL); } +u64 efivar_reserved_space(void) +{ + if (efi_no_storage_paranoia) + return 0; + return EFI_MIN_RESERVE; +} +EXPORT_SYMBOL_GPL(efivar_reserved_space); + /* * In the nonblocking case we do not attempt to perform garbage * collection if we do not have enough free space. Rather, we do the diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c index abeff7dc0b581..d0dfa007bffcc 100644 --- a/drivers/firmware/efi/efi.c +++ b/drivers/firmware/efi/efi.c @@ -211,6 +211,7 @@ static int generic_ops_register(void) generic_ops.get_variable = efi.get_variable; generic_ops.get_next_variable = efi.get_next_variable; generic_ops.query_variable_store = efi_query_variable_store; + generic_ops.query_variable_info = efi.query_variable_info; if (efi_rt_services_supported(EFI_RT_SUPPORTED_SET_VARIABLE)) { generic_ops.set_variable = efi.set_variable; diff --git a/drivers/firmware/efi/vars.c b/drivers/firmware/efi/vars.c index bfc5fa6aa47b6..e9dc7116daf13 100644 --- a/drivers/firmware/efi/vars.c +++ b/drivers/firmware/efi/vars.c @@ -245,3 +245,15 @@ efi_status_t efivar_set_variable(efi_char16_t *name, efi_guid_t *vendor, return status; } EXPORT_SYMBOL_NS_GPL(efivar_set_variable, EFIVAR); + +efi_status_t efivar_query_variable_info(u32 attr, + u64 *storage_space, + u64 *remaining_space, + u64 *max_variable_size) +{ + if (!__efivars->ops->query_variable_info) + return EFI_UNSUPPORTED; + return __efivars->ops->query_variable_info(attr, storage_space, + remaining_space, max_variable_size); +} +EXPORT_SYMBOL_NS_GPL(efivar_query_variable_info, EFIVAR); diff --git a/fs/efivarfs/super.c b/fs/efivarfs/super.c index 482d612b716bb..e028fafa04f38 100644 --- a/fs/efivarfs/super.c +++ b/fs/efivarfs/super.c @@ -13,6 +13,7 @@ #include #include #include +#include #include "internal.h" @@ -23,8 +24,44 @@ static void efivarfs_evict_inode(struct inode *inode) clear_inode(inode); } +static int efivarfs_statfs(struct dentry *dentry, struct kstatfs *buf) +{ + const u32 attr = EFI_VARIABLE_NON_VOLATILE | + EFI_VARIABLE_BOOTSERVICE_ACCESS | + EFI_VARIABLE_RUNTIME_ACCESS; + u64 storage_space, remaining_space, max_variable_size; + efi_status_t status; + + status = efivar_query_variable_info(attr, &storage_space, &remaining_space, + &max_variable_size); + if (status != EFI_SUCCESS) + return efi_status_to_err(status); + + /* + * This is not a normal filesystem, so no point in pretending it has a block + * size; we declare f_bsize to 1, so that we can then report the exact value + * sent by EFI QueryVariableInfo in f_blocks and f_bfree + */ + buf->f_bsize = 1; + buf->f_namelen = NAME_MAX; + buf->f_blocks = storage_space; + buf->f_bfree = remaining_space; + buf->f_type = dentry->d_sb->s_magic; + + /* + * In f_bavail we declare the free space that the kernel will allow writing + * when the storage_paranoia x86 quirk is active. To use more, users + * should boot the kernel with efi_no_storage_paranoia. + */ + if (remaining_space > efivar_reserved_space()) + buf->f_bavail = remaining_space - efivar_reserved_space(); + else + buf->f_bavail = 0; + + return 0; +} static const struct super_operations efivarfs_ops = { - .statfs = simple_statfs, + .statfs = efivarfs_statfs, .drop_inode = generic_delete_inode, .evict_inode = efivarfs_evict_inode, }; diff --git a/include/linux/efi.h b/include/linux/efi.h index 7aa62c92185f6..bed3c92cbc318 100644 --- a/include/linux/efi.h +++ b/include/linux/efi.h @@ -1042,6 +1042,7 @@ struct efivar_operations { efi_set_variable_t *set_variable; efi_set_variable_t *set_variable_nonblocking; efi_query_variable_store_t *query_variable_store; + efi_query_variable_info_t *query_variable_info; }; struct efivars { @@ -1049,6 +1050,12 @@ struct efivars { const struct efivar_operations *ops; }; +#ifdef CONFIG_X86 +u64 __attribute_const__ efivar_reserved_space(void); +#else +static inline u64 efivar_reserved_space(void) { return 0; } +#endif + /* * The maximum size of VariableName + Data = 1024 * Therefore, it's reasonable to save that much @@ -1087,6 +1094,10 @@ efi_status_t efivar_set_variable_locked(efi_char16_t *name, efi_guid_t *vendor, efi_status_t efivar_set_variable(efi_char16_t *name, efi_guid_t *vendor, u32 attr, unsigned long data_size, void *data); +efi_status_t efivar_query_variable_info(u32 attr, u64 *storage_space, + u64 *remaining_space, + u64 *max_variable_size); + #if IS_ENABLED(CONFIG_EFI_CAPSULE_LOADER) extern bool efi_capsule_pending(int *reset_type);