Commit f1f990a8 authored by Heinrich Schuchardt's avatar Heinrich Schuchardt 💬

efi_loader: memory buffer for variables

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's avatarHeinrich Schuchardt <xypron.glpk@gmx.de>
parent b0dd8cb4
......@@ -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
......@@ -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
......
// 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);
if (match)
efi_current_var = var;
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;
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;
memmove(var, next, (uintptr_t)last - (uintptr_t)next);
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;
}
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