[PATCH v2 14/17] efi_loader: memory buffer for variables
Heinrich Schuchardt
xypron.glpk at gmx.de
Tue Jul 7 05:11:57 CEST 2020
Saving UEFI variable as encoded U-Boot environment variables does not allow
support at runtime.
Provide functions to manage a memory buffer with UEFI variables.
Signed-off-by: Heinrich Schuchardt <xypron.glpk at gmx.de>
---
include/efi_variable.h | 54 +++++++
lib/efi_loader/Makefile | 1 +
lib/efi_loader/efi_var_mem.c | 266 +++++++++++++++++++++++++++++++++++
3 files changed, 321 insertions(+)
create mode 100644 lib/efi_loader/efi_var_mem.c
diff --git a/include/efi_variable.h b/include/efi_variable.h
index 01054209c4..bc5985cfdb 100644
--- a/include/efi_variable.h
+++ b/include/efi_variable.h
@@ -141,4 +141,58 @@ efi_status_t efi_var_to_file(void);
*/
efi_status_t efi_var_from_file(void);
+/**
+ * efi_var_mem_init() - set-up variable list
+ *
+ * Return: status code
+ */
+efi_status_t efi_var_mem_init(void);
+
+/**
+ * efi_var_mem_find() - find a variable in the list
+ *
+ * @guid: GUID of the variable
+ * @name: name of the variable
+ * @next: on exit pointer to the next variable after the found one
+ * Return: found variable
+ */
+struct efi_var_entry *efi_var_mem_find(const efi_guid_t *guid, const u16 *name,
+ struct efi_var_entry **next);
+
+/**
+ * efi_var_mem_del() - delete a variable from the list of variables
+ *
+ * @var: variable to delete
+ */
+void efi_var_mem_del(struct efi_var_entry *var);
+
+/**
+ * efi_var_mem_ins() - append a variable to the list of variables
+ *
+ * The variable is appended without checking if a variable of the same name
+ * already exists. The two data buffers are concatenated.
+ *
+ * @variable_name: variable name
+ * @vendor: GUID
+ * @attributes: variable attributes
+ * @size1: size of the first data buffer
+ * @data1: first data buffer
+ * @size2: size of the second data field
+ * @data2: second data buffer
+ * @time: time of authentication (as seconds since start of epoch)
+ * Result: status code
+ */
+efi_status_t efi_var_mem_ins(u16 *variable_name,
+ const efi_guid_t *vendor, u32 attributes,
+ const efi_uintn_t size1, const void *data1,
+ const efi_uintn_t size2, const void *data2,
+ const u64 time);
+
+/**
+ * efi_var_mem_free() - determine free memory for variables
+ *
+ * Return: maximum data size plus variable name size
+ */
+u64 efi_var_mem_free(void);
+
#endif
diff --git a/lib/efi_loader/Makefile b/lib/efi_loader/Makefile
index c87b82db32..f81ec8d277 100644
--- a/lib/efi_loader/Makefile
+++ b/lib/efi_loader/Makefile
@@ -36,6 +36,7 @@ obj-y += efi_runtime.o
obj-y += efi_setup.o
obj-$(CONFIG_EFI_UNICODE_COLLATION_PROTOCOL2) += efi_unicode_collation.o
obj-y += efi_var_common.o
+obj-y += efi_var_mem.o
ifeq ($(CONFIG_EFI_MM_COMM_TEE),y)
obj-y += efi_variable_tee.o
else
diff --git a/lib/efi_loader/efi_var_mem.c b/lib/efi_loader/efi_var_mem.c
new file mode 100644
index 0000000000..ac55d8f8dc
--- /dev/null
+++ b/lib/efi_loader/efi_var_mem.c
@@ -0,0 +1,266 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * File interface for UEFI variables
+ *
+ * Copyright (c) 2020, Heinrich Schuchardt
+ */
+
+#include <common.h>
+#include <efi_loader.h>
+#include <efi_variable.h>
+#include <u-boot/crc.h>
+
+static struct efi_var_file __efi_runtime_data *efi_var_buf;
+static struct efi_var_entry __efi_runtime_data *efi_current_var;
+
+/**
+ * efi_var_mem_compare() - compare GUID and name with a variable
+ *
+ * @var: variable to compare
+ * @guid: GUID to compare
+ * @name: variable name to compare
+ * @next: pointer to next variable
+ * Return: true if match
+ */
+static bool __efi_runtime
+efi_var_mem_compare(struct efi_var_entry *var, const efi_guid_t *guid,
+ const u16 *name, struct efi_var_entry **next)
+{
+ int i;
+ u8 *guid1, *guid2;
+ const u16 *data, *var_name;
+ bool match = true;
+
+ for (guid1 = (u8 *)&var->guid, guid2 = (u8 *)guid, i = 0;
+ i < sizeof(efi_guid_t) && match; ++i)
+ match = (guid1[i] == guid2[i]);
+
+ for (data = var->name, var_name = name;; ++data, ++var_name) {
+ if (match)
+ match = (*data == *var_name);
+ if (!*data)
+ break;
+ }
+
+ ++data;
+
+ if (next)
+ *next = (struct efi_var_entry *)
+ ALIGN((uintptr_t)data + var->length, 8);
+
+ return match;
+}
+
+struct efi_var_entry __efi_runtime
+*efi_var_mem_find(const efi_guid_t *guid, const u16 *name,
+ struct efi_var_entry **next)
+{
+ struct efi_var_entry *var, *last;
+
+ last = (struct efi_var_entry *)
+ ((uintptr_t)efi_var_buf + efi_var_buf->length);
+
+ if (!*name) {
+ if (next) {
+ *next = efi_var_buf->var;
+ if (*next >= last)
+ *next = NULL;
+ }
+ return NULL;
+ }
+ if (efi_current_var &&
+ efi_var_mem_compare(efi_current_var, guid, name, next)) {
+ if (next && *next >= last)
+ *next = NULL;
+ return efi_current_var;
+ }
+
+ var = efi_var_buf->var;
+ if (var < last) {
+ for (; var;) {
+ struct efi_var_entry *pos;
+ bool match;
+
+ match = efi_var_mem_compare(var, guid, name, &pos);
+ if (pos >= last)
+ pos = NULL;
+ if (match) {
+ if (next)
+ *next = pos;
+ return var;
+ }
+ var = pos;
+ }
+ }
+ if (next)
+ *next = NULL;
+ return NULL;
+}
+
+void __efi_runtime efi_var_mem_del(struct efi_var_entry *var)
+{
+ u16 *data;
+ struct efi_var_entry *next, *last;
+ u64 *from, *to;
+
+ if (!var)
+ return;
+
+ last = (struct efi_var_entry *)
+ ((uintptr_t)efi_var_buf + efi_var_buf->length);
+ if (var < efi_current_var)
+ efi_current_var = NULL;
+
+ for (data = var->name; *data; ++data)
+ ;
+ ++data;
+ next = (struct efi_var_entry *)
+ ALIGN((uintptr_t)data + var->length, 8);
+ efi_var_buf->length -= (uintptr_t)next - (uintptr_t)var;
+
+ for (to = (u64 *)var, from = (u64 *)next; from < (u64 *)last;
+ ++to, ++from)
+ *to = *from;
+ efi_var_buf->crc32 = crc32(0, (u8 *)efi_var_buf->var,
+ efi_var_buf->length -
+ sizeof(struct efi_var_file));
+}
+
+efi_status_t __efi_runtime efi_var_mem_ins(
+ u16 *variable_name,
+ const efi_guid_t *vendor, u32 attributes,
+ const efi_uintn_t size1, const void *data1,
+ const efi_uintn_t size2, const void *data2,
+ const u64 time)
+{
+ u16 *data;
+ struct efi_var_entry *var;
+ u32 var_name_len;
+
+ var = (struct efi_var_entry *)
+ ((uintptr_t)efi_var_buf + efi_var_buf->length);
+ for (var_name_len = 0; variable_name[var_name_len]; ++var_name_len)
+ ;
+ ++var_name_len;
+ data = var->name + var_name_len;
+
+ if ((uintptr_t)data - (uintptr_t)efi_var_buf + size1 + size2 >
+ EFI_VAR_BUF_SIZE)
+ return EFI_OUT_OF_RESOURCES;
+
+ var->attr = attributes;
+ var->length = size1 + size2;
+ var->time = time;
+
+ efi_memcpy_runtime(&var->guid, vendor, sizeof(efi_guid_t));
+ efi_memcpy_runtime(var->name, variable_name,
+ sizeof(u16) * var_name_len);
+ efi_memcpy_runtime(data, data1, size1);
+ efi_memcpy_runtime((u8 *)data + size1, data2, size2);
+
+ var = (struct efi_var_entry *)
+ ALIGN((uintptr_t)data + var->length, 8);
+ efi_var_buf->length = (uintptr_t)var - (uintptr_t)efi_var_buf;
+ efi_var_buf->crc32 = crc32(0, (u8 *)efi_var_buf->var,
+ efi_var_buf->length -
+ sizeof(struct efi_var_file));
+
+ return EFI_SUCCESS;
+}
+
+u64 __efi_runtime efi_var_mem_free(void)
+{
+ return EFI_VAR_BUF_SIZE - efi_var_buf->length -
+ sizeof(struct efi_var_entry);
+}
+
+/**
+ * efi_var_mem_bs_del() - delete boot service only variables
+ */
+static void efi_var_mem_bs_del(void)
+{
+ struct efi_var_entry *var = efi_var_buf->var;
+
+ for (;;) {
+ struct efi_var_entry *last;
+
+ last = (struct efi_var_entry *)
+ ((uintptr_t)efi_var_buf + efi_var_buf->length);
+ if (var >= last)
+ break;
+ if (var->attr & EFI_VARIABLE_RUNTIME_ACCESS) {
+ u16 *data;
+
+ /* skip variable */
+ for (data = var->name; *data; ++data)
+ ;
+ ++data;
+ var = (struct efi_var_entry *)
+ ALIGN((uintptr_t)data + var->length, 8);
+ } else {
+ /* delete variable */
+ efi_var_mem_del(var);
+ }
+ }
+}
+
+/**
+ * efi_var_mem_notify_exit_boot_services() - ExitBootService callback
+ *
+ * @event: callback event
+ * @context: callback context
+ */
+static void EFIAPI __efi_runtime
+efi_var_mem_notify_exit_boot_services(struct efi_event *event, void *context)
+{
+ EFI_ENTRY("%p, %p", event, context);
+
+ /* Delete boot service only variables */
+ efi_var_mem_bs_del();
+
+ EFI_EXIT(EFI_SUCCESS);
+}
+
+/**
+ * efi_var_mem_notify_exit_boot_services() - SetVirtualMemoryMap callback
+ *
+ * @event: callback event
+ * @context: callback context
+ */
+static void EFIAPI __efi_runtime
+efi_var_mem_notify_virtual_address_map(struct efi_event *event, void *context)
+{
+ efi_convert_pointer(0, (void **)&efi_var_buf);
+}
+
+efi_status_t efi_var_mem_init(void)
+{
+ u64 memory;
+ efi_status_t ret;
+ struct efi_event *event;
+
+ ret = efi_allocate_pages(EFI_ALLOCATE_ANY_PAGES,
+ EFI_RUNTIME_SERVICES_DATA,
+ efi_size_in_pages(EFI_VAR_BUF_SIZE),
+ &memory);
+ if (ret != EFI_SUCCESS)
+ return ret;
+ efi_var_buf = (struct efi_var_file *)(uintptr_t)memory;
+ memset(efi_var_buf, 0, EFI_VAR_BUF_SIZE);
+ efi_var_buf->magic = EFI_VAR_FILE_MAGIC;
+ efi_var_buf->length = (uintptr_t)efi_var_buf->var -
+ (uintptr_t)efi_var_buf;
+ /* crc32 for 0 bytes = 0 */
+
+ ret = efi_create_event(EVT_SIGNAL_EXIT_BOOT_SERVICES, TPL_CALLBACK,
+ efi_var_mem_notify_exit_boot_services, NULL,
+ NULL, &event);
+ if (ret != EFI_SUCCESS)
+ return ret;
+ ret = efi_create_event(EVT_SIGNAL_VIRTUAL_ADDRESS_CHANGE, TPL_CALLBACK,
+ efi_var_mem_notify_virtual_address_map, NULL,
+ NULL, &event);
+ if (ret != EFI_SUCCESS)
+ return ret;
+ return ret;
+}
--
2.27.0
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