From 6365a1935c5151455812e96d8de434c551dc0d98 Mon Sep 17 00:00:00 2001 From: Ma Wupeng Date: Tue, 14 Jun 2022 17:21:52 +0800 Subject: efi: Make code to find mirrored memory ranges generic Commit b05b9f5f9dcf ("x86, mirror: x86 enabling - find mirrored memory ranges") introduce the efi_find_mirror() function on x86. In order to reuse the API we make it public. Arm64 can support mirrored memory too, so function efi_find_mirror() is added to efi_init() to this support for arm64. Since efi_init() is shared by ARM, arm64 and riscv, this patch will bring mirror memory support for these architectures, but this support is only tested in arm64. Signed-off-by: Ma Wupeng Link: https://lore.kernel.org/r/20220614092156.1972846-2-mawupeng1@huawei.com [ardb: fix subject to better reflect the payload] Acked-by: Mike Rapoport Signed-off-by: Ard Biesheuvel --- include/linux/efi.h | 3 +++ 1 file changed, 3 insertions(+) (limited to 'include/linux') diff --git a/include/linux/efi.h b/include/linux/efi.h index 7d9b0bb47eb3..53f64c14a525 100644 --- a/include/linux/efi.h +++ b/include/linux/efi.h @@ -872,6 +872,7 @@ static inline bool efi_rt_services_supported(unsigned int mask) { return (efi.runtime_supported_mask & mask) == mask; } +extern void efi_find_mirror(void); #else static inline bool efi_enabled(int feature) { @@ -889,6 +890,8 @@ static inline bool efi_rt_services_supported(unsigned int mask) { return false; } + +static inline void efi_find_mirror(void) {} #endif extern int efi_status_to_err(efi_status_t status); -- cgit v1.2.3 From 8ca869b24538a7b5501af368e87e4a59b0c04117 Mon Sep 17 00:00:00 2001 From: Ard Biesheuvel Date: Wed, 22 Jun 2022 09:31:31 +0200 Subject: pstore: Add priv field to pstore_record for backend specific use The EFI pstore backend will need to store per-record variable name data when we switch away from the efivars layer. Add a priv field to struct pstore_record, and document it as holding a backend specific pointer that is assumed to be a kmalloc()d buffer, and will be kfree()d when the entire record is freed. Acked-by: Kees Cook Signed-off-by: Ard Biesheuvel --- include/linux/pstore.h | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'include/linux') diff --git a/include/linux/pstore.h b/include/linux/pstore.h index e97a8188f0fd..638507a3c8ff 100644 --- a/include/linux/pstore.h +++ b/include/linux/pstore.h @@ -57,6 +57,9 @@ struct pstore_info; * @size: size of @buf * @ecc_notice_size: * ECC information for @buf + * @priv: pointer for backend specific use, will be + * kfree()d by the pstore core if non-NULL + * when the record is freed. * * Valid for PSTORE_TYPE_DMESG @type: * @@ -74,6 +77,7 @@ struct pstore_record { char *buf; ssize_t size; ssize_t ecc_notice_size; + void *priv; int count; enum kmsg_dump_reason reason; -- cgit v1.2.3 From ec3507b2ca51286de6ecd85fdac8e722219cdef8 Mon Sep 17 00:00:00 2001 From: Ard Biesheuvel Date: Mon, 20 Jun 2022 17:04:32 +0200 Subject: efi: vars: Don't drop lock in the middle of efivar_init() Even though the efivars_lock lock is documented as protecting the efivars->ops pointer (among other things), efivar_init() happily releases and reacquires the lock for every EFI variable that it enumerates. This used to be needed because the lock was originally a spinlock, which prevented the callback that is invoked for every variable from being able to sleep. However, releasing the lock could potentially invalidate the ops pointer, but more importantly, it might allow a SetVariable() runtime service call to take place concurrently, and the UEFI spec does not define how this affects an enumeration that is running in parallel using the GetNextVariable() runtime service, which is what efivar_init() uses. In the meantime, the lock has been converted into a semaphore, and the only reason we need to drop the lock is because the efivarfs pseudo filesystem driver will otherwise deadlock when it invokes the efivars API from the callback to create the efivar_entry items and insert them into the linked list. (EFI pstore is affected in a similar way) So let's switch to helpers that can be used while the lock is already taken. This way, we can hold on to the lock throughout the enumeration. Signed-off-by: Ard Biesheuvel --- include/linux/efi.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/linux') diff --git a/include/linux/efi.h b/include/linux/efi.h index 53f64c14a525..56f04b6daeb0 100644 --- a/include/linux/efi.h +++ b/include/linux/efi.h @@ -1064,6 +1064,7 @@ int efivar_init(int (*func)(efi_char16_t *, efi_guid_t, unsigned long, void *), void *data, bool duplicates, struct list_head *head); int efivar_entry_add(struct efivar_entry *entry, struct list_head *head); +void __efivar_entry_add(struct efivar_entry *entry, struct list_head *head); int efivar_entry_remove(struct efivar_entry *entry); int __efivar_entry_delete(struct efivar_entry *entry); -- cgit v1.2.3 From 472831d4c4b2d8eac783b256e5c829487d5310df Mon Sep 17 00:00:00 2001 From: Ard Biesheuvel Date: Mon, 20 Jun 2022 13:17:20 +0200 Subject: efi: vars: Add thin wrapper around EFI get/set variable interface The current efivars layer is a jumble of list iterators, shadow data structures and safe variable manipulation helpers that really belong in the efivarfs pseudo file system once the obsolete sysfs access method to EFI variables is removed. So split off a minimal efivar get/set variable API that reuses the existing efivars_lock semaphore to mediate access to the various runtime services, primarily to ensure that performing a SetVariable() on one CPU while another is calling GetNextVariable() in a loop to enumerate the contents of the EFI variable store does not result in surprises. Signed-off-by: Ard Biesheuvel --- include/linux/efi.h | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) (limited to 'include/linux') diff --git a/include/linux/efi.h b/include/linux/efi.h index 56f04b6daeb0..c828ab6f0e2a 100644 --- a/include/linux/efi.h +++ b/include/linux/efi.h @@ -1099,6 +1099,26 @@ bool efivar_validate(efi_guid_t vendor, efi_char16_t *var_name, u8 *data, bool efivar_variable_is_removable(efi_guid_t vendor, const char *name, size_t len); +int efivar_lock(void); +int efivar_trylock(void); +void efivar_unlock(void); + +efi_status_t efivar_get_variable(efi_char16_t *name, efi_guid_t *vendor, + u32 *attr, unsigned long *size, void *data); + +efi_status_t efivar_get_next_variable(unsigned long *name_size, + efi_char16_t *name, efi_guid_t *vendor); + +efi_status_t efivar_set_variable_locked(efi_char16_t *name, efi_guid_t *vendor, + u32 attr, unsigned long data_size, + void *data, bool nonblocking); + +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 check_var_size(u32 attributes, unsigned long size); +efi_status_t check_var_size_nonblocking(u32 attributes, unsigned long size); + #if IS_ENABLED(CONFIG_EFI_CAPSULE_LOADER) extern bool efi_capsule_pending(int *reset_type); -- cgit v1.2.3 From 859748255b43460685e93a1f8a40b8cdc3be02f2 Mon Sep 17 00:00:00 2001 From: Ard Biesheuvel Date: Mon, 20 Jun 2022 13:21:26 +0200 Subject: efi: pstore: Omit efivars caching EFI varstore access layer Avoid the efivars layer and simply call the newly introduced EFI varstore helpers instead. This simplifies the code substantially, and also allows us to remove some hacks in the shared efivars layer that were added for efi-pstore specifically. In order to be able to delete the EFI variable associated with a record, store the UTF-16 name of the variable in the pstore record's priv field. That way, we don't have to make guesses regarding which variable the record may have been loaded from. Signed-off-by: Ard Biesheuvel --- include/linux/efi.h | 2 -- 1 file changed, 2 deletions(-) (limited to 'include/linux') diff --git a/include/linux/efi.h b/include/linux/efi.h index c828ab6f0e2a..08bc6215e3b4 100644 --- a/include/linux/efi.h +++ b/include/linux/efi.h @@ -1043,8 +1043,6 @@ struct efivar_entry { struct efi_variable var; struct list_head list; struct kobject kobj; - bool scanning; - bool deleting; }; static inline void -- cgit v1.2.3 From 3a75f9f2f9ad19bb9a0f566373ae91d8f09db85e Mon Sep 17 00:00:00 2001 From: Ard Biesheuvel Date: Tue, 21 Jun 2022 15:48:29 +0200 Subject: efi: vars: Use locking version to iterate over efivars linked lists Both efivars and efivarfs uses __efivar_entry_iter() to go over the linked list that shadows the list of EFI variables held by the firmware, but fail to call the begin/end helpers that are documented as a prerequisite. So switch to the proper version, which is efivar_entry_iter(). Given that in both cases, efivar_entry_remove() is invoked with the lock held already, don't take the lock there anymore. Signed-off-by: Ard Biesheuvel --- include/linux/efi.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include/linux') diff --git a/include/linux/efi.h b/include/linux/efi.h index 08bc6215e3b4..54ca2d6b6c78 100644 --- a/include/linux/efi.h +++ b/include/linux/efi.h @@ -1063,7 +1063,7 @@ int efivar_init(int (*func)(efi_char16_t *, efi_guid_t, unsigned long, void *), int efivar_entry_add(struct efivar_entry *entry, struct list_head *head); void __efivar_entry_add(struct efivar_entry *entry, struct list_head *head); -int efivar_entry_remove(struct efivar_entry *entry); +void efivar_entry_remove(struct efivar_entry *entry); int __efivar_entry_delete(struct efivar_entry *entry); int efivar_entry_delete(struct efivar_entry *entry); -- cgit v1.2.3 From 5ac941367a6f85777ef34ec15d60e17ea8e446d4 Mon Sep 17 00:00:00 2001 From: Ard Biesheuvel Date: Tue, 21 Jun 2022 15:54:53 +0200 Subject: efi: vars: Drop __efivar_entry_iter() helper which is no longer used __efivar_entry_iter() uses a list iterator in a dubious way, i.e., it assumes that the iteration variable always points to an object of the appropriate type, even if the list traversal exhausts the list completely, in which case it will point somewhere in the vicinity of the list's anchor instead. Fortunately, we no longer use this function so we can just get rid of it entirely. Signed-off-by: Ard Biesheuvel --- include/linux/efi.h | 3 --- 1 file changed, 3 deletions(-) (limited to 'include/linux') diff --git a/include/linux/efi.h b/include/linux/efi.h index 54ca2d6b6c78..93ce85a14a46 100644 --- a/include/linux/efi.h +++ b/include/linux/efi.h @@ -1083,9 +1083,6 @@ int efivar_entry_set_safe(efi_char16_t *name, efi_guid_t vendor, u32 attributes, int efivar_entry_iter_begin(void); void efivar_entry_iter_end(void); -int __efivar_entry_iter(int (*func)(struct efivar_entry *, void *), - struct list_head *head, void *data, - struct efivar_entry **prev); int efivar_entry_iter(int (*func)(struct efivar_entry *, void *), struct list_head *head, void *data); -- cgit v1.2.3 From 8add9a3a2243166f8f60fc20e876caaf30a333f7 Mon Sep 17 00:00:00 2001 From: Sudeep Holla Date: Tue, 28 Jun 2022 15:18:21 +0100 Subject: efi: Simplify arch_efi_call_virt() macro Currently, the arch_efi_call_virt() assumes all users of it will have defined a type 'efi_##f##_t' to make use of it. Simplify the arch_efi_call_virt() macro by eliminating the explicit need for efi_##f##_t type for every user of this macro. Signed-off-by: Sudeep Holla Acked-by: Russell King (Oracle) [ardb: apply Sudeep's ARM fix to i686, Loongarch and RISC-V too] Signed-off-by: Ard Biesheuvel --- include/linux/efi.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'include/linux') diff --git a/include/linux/efi.h b/include/linux/efi.h index 93ce85a14a46..9ff63acef1ec 100644 --- a/include/linux/efi.h +++ b/include/linux/efi.h @@ -1200,6 +1200,8 @@ static inline void efi_check_for_embedded_firmwares(void) { } efi_status_t efi_random_get_seed(void); +#define arch_efi_call_virt(p, f, args...) ((p)->f(args)) + /* * Arch code can implement the following three template macros, avoiding * reptition for the void/non-void return cases of {__,}efi_call_virt(): -- cgit v1.2.3