Mapping from EFI variables to grub variables. Still almost as many
TODOs as lines of code, but just figured I'd send out an early version
for comments.
I was thinking of it as a useful way for u-boot to pass values to grub
(although grub is still missing a way for grub scripts to retrieve
UEFI variables).
The rough idea is to encode GUID + variable name plus "efi_" prefix
(to avoid unintended u-boot variables leaking into the UEFI world).
And then encode the type (and attributes?) in the string value of the
variable. Ie. something like:
setenv efi_8be4df6193ca11d2aa0d00e098032b8c_OsIndicationsSupported (u64)0
---
cmd/bootefi.c | 3 +
include/efi.h | 19 ++++
include/efi_loader.h | 10 ++
lib/efi_loader/Makefile | 1 +
lib/efi_loader/efi_runtime.c | 17 ++-
lib/efi_loader/efi_util.h | 79 ++++++++++++++
lib/efi_loader/efi_variable.c | 235 ++++++++++++++++++++++++++++++++++++++++++
7 files changed, 360 insertions(+), 4 deletions(-)
create mode 100644 lib/efi_loader/efi_util.h
create mode 100644 lib/efi_loader/efi_variable.c
diff --git a/cmd/bootefi.c b/cmd/bootefi.c
index 4f11682..56f6bc4 100644
--- a/cmd/bootefi.c
+++ b/cmd/bootefi.c
@@ -300,6 +300,9 @@ static unsigned long do_bootefi_exec(void *efi, void *fdt)
efi_reset_system_init();
efi_get_time_init();
+ /* we don't support much: */
+ setenv("efi_61dfe48bca93d211aa0d00e098032b8c_OsIndicationsSupported",
"(u64)0");
+
/* Call our payload! */
debug("%s:%d Jumping to 0x%lx\n", __func__, __LINE__, (long)entry);
diff --git a/include/efi.h b/include/efi.h
index 3d58780..f819c5b 100644
--- a/include/efi.h
+++ b/include/efi.h
@@ -294,6 +294,25 @@ extern char image_base[];
/* Start and end of U-Boot image (for payload) */
extern char _binary_u_boot_bin_start[], _binary_u_boot_bin_end[];
+/*
+ * Variable Attributes
+ */
+#define EFI_VARIABLE_NON_VOLATILE 0x0000000000000001
+#define EFI_VARIABLE_BOOTSERVICE_ACCESS 0x0000000000000002
+#define EFI_VARIABLE_RUNTIME_ACCESS 0x0000000000000004
+#define EFI_VARIABLE_HARDWARE_ERROR_RECORD 0x0000000000000008
+#define EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS 0x0000000000000010
+#define EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS 0x0000000000000020
+#define EFI_VARIABLE_APPEND_WRITE 0x0000000000000040
+
+#define EFI_VARIABLE_MASK (EFI_VARIABLE_NON_VOLATILE | \
+ EFI_VARIABLE_BOOTSERVICE_ACCESS | \
+ EFI_VARIABLE_RUNTIME_ACCESS | \
+ EFI_VARIABLE_HARDWARE_ERROR_RECORD | \
+ EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS | \
+
EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS | \
+ EFI_VARIABLE_APPEND_WRITE)
+
/**
* efi_get_sys_table() - Get access to the main EFI system table
*
diff --git a/include/efi_loader.h b/include/efi_loader.h
index 99619f5..812ec10 100644
--- a/include/efi_loader.h
+++ b/include/efi_loader.h
@@ -176,6 +176,16 @@ efi_status_t __efi_runtime EFIAPI efi_get_time(
struct efi_time_cap *capabilities);
void efi_get_time_init(void);
+efi_status_t EFIAPI efi_get_variable(s16 *variable_name,
+ efi_guid_t *vendor, u32 *attributes,
+ unsigned long *data_size, void *data);
+efi_status_t EFIAPI efi_get_next_variable(
+ unsigned long *variable_name_size,
+ s16 *variable_name, efi_guid_t *vendor);
+efi_status_t EFIAPI efi_set_variable(s16 *variable_name,
+ efi_guid_t *vendor, u32 attributes,
+ unsigned long data_size, void *data);
+
#else /* defined(EFI_LOADER) && !defined(CONFIG_SPL_BUILD) */
/* Without CONFIG_EFI_LOADER we don't have a runtime section, stub it out */
diff --git a/lib/efi_loader/Makefile b/lib/efi_loader/Makefile
index 3c230ac..9c67367 100644
--- a/lib/efi_loader/Makefile
+++ b/lib/efi_loader/Makefile
@@ -16,6 +16,7 @@ always := $(efiprogs-y)
obj-$(CONFIG_CMD_BOOTEFI_HELLO) += helloworld_efi.o
obj-y += efi_image_loader.o efi_boottime.o efi_runtime.o efi_console.o
obj-y += efi_memory.o
+obj-y += efi_variable.o
obj-$(CONFIG_LCD) += efi_gop.o
obj-$(CONFIG_DM_VIDEO) += efi_gop.o
obj-$(CONFIG_PARTITIONS) += efi_disk.o
diff --git a/lib/efi_loader/efi_runtime.c b/lib/efi_loader/efi_runtime.c
index dd52755..7615090 100644
--- a/lib/efi_loader/efi_runtime.c
+++ b/lib/efi_loader/efi_runtime.c
@@ -184,7 +184,16 @@ static const struct efi_runtime_detach_list_struct
efi_runtime_detach_list[] = {
/* Clean up system table */
.ptr = &systab.boottime,
.patchto = NULL,
- },
+ }, {
+ .ptr = &efi_runtime_services.get_variable,
+ .patchto = &efi_device_error,
+ }, {
+ .ptr = &efi_runtime_services.get_next_variable,
+ .patchto = &efi_device_error,
+ }, {
+ .ptr = &efi_runtime_services.set_variable,
+ .patchto = &efi_device_error,
+ }
};
static bool efi_runtime_tobedetached(void *p)
@@ -382,9 +391,9 @@ struct efi_runtime_services __efi_runtime_data
efi_runtime_services = {
.set_wakeup_time = (void *)&efi_unimplemented,
.set_virtual_address_map = &efi_set_virtual_address_map,
.convert_pointer = (void *)&efi_invalid_parameter,
- .get_variable = (void *)&efi_device_error,
- .get_next_variable = (void *)&efi_device_error,
- .set_variable = (void *)&efi_device_error,
+ .get_variable = efi_get_variable,
+ .get_next_variable = efi_get_next_variable,
+ .set_variable = efi_set_variable,
.get_next_high_mono_count = (void *)&efi_device_error,
.reset_system = &efi_reset_system_boottime,
};
diff --git a/lib/efi_loader/efi_util.h b/lib/efi_loader/efi_util.h
new file mode 100644
index 0000000..a566e81
--- /dev/null
+++ b/lib/efi_loader/efi_util.h
@@ -0,0 +1,79 @@
+/*
+ * EFI utils
+ *
+ * Copyright (c) 2017 Rob Clark
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ */
+
+#ifndef __EFI_UTIL_H_
+#define __EFI_UTIL_H_
+
+/*
+ * utf8/utf16 conversion lifted from grub
+ */
+
+static inline int
+utf16_strlen(uint16_t *in)
+{
+ int i;
+ for (i = 0; in[i]; i++);
+ return i;
+}
+
+/* Convert UTF-16 to UTF-8. */
+static inline uint8_t *
+utf16_to_utf8(uint8_t *dest, const uint16_t *src, size_t size)
+{
+ uint32_t code_high = 0;
+
+ while (size--) {
+ uint32_t code = *src++;
+
+ if (code_high) {
+ if (code >= 0xDC00 && code <= 0xDFFF) {
+ /* Surrogate pair. */
+ code = ((code_high - 0xD800) << 10) + (code -
0xDC00) + 0x10000;
+
+ *dest++ = (code >> 18) | 0xF0;
+ *dest++ = ((code >> 12) & 0x3F) | 0x80;
+ *dest++ = ((code >> 6) & 0x3F) | 0x80;
+ *dest++ = (code & 0x3F) | 0x80;
+ } else {
+ /* Error... */
+ *dest++ = '?';
+ /* *src may be valid. Don't eat it. */
+ src--;
+ }
+
+ code_high = 0;
+ } else {
+ if (code <= 0x007F) {
+ *dest++ = code;
+ } else if (code <= 0x07FF) {
+ *dest++ = (code >> 6) | 0xC0;
+ *dest++ = (code & 0x3F) | 0x80;
+ } else if (code >= 0xD800 && code <= 0xDBFF) {
+ code_high = code;
+ continue;
+ } else if (code >= 0xDC00 && code <= 0xDFFF) {
+ /* Error... */
+ *dest++ = '?';
+ } else if (code < 0x10000) {
+ *dest++ = (code >> 12) | 0xE0;
+ *dest++ = ((code >> 6) & 0x3F) | 0x80;
+ *dest++ = (code & 0x3F) | 0x80;
+ } else {
+ *dest++ = (code >> 18) | 0xF0;
+ *dest++ = ((code >> 12) & 0x3F) | 0x80;
+ *dest++ = ((code >> 6) & 0x3F) | 0x80;
+ *dest++ = (code & 0x3F) | 0x80;
+ }
+ }
+ }
+
+ return dest;
+}
+
+
+#endif /* __EFI_UTIL_H_ */
diff --git a/lib/efi_loader/efi_variable.c b/lib/efi_loader/efi_variable.c
new file mode 100644
index 0000000..5343f49
--- /dev/null
+++ b/lib/efi_loader/efi_variable.c
@@ -0,0 +1,235 @@
+/*
+ * EFI utils
+ *
+ * Copyright (c) 2017 Rob Clark
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ */
+
+#include <efi_loader.h>
+#include "efi_util.h"
+
+
+/* Mapping between EFI variables and u-boot variables:
+ *
+ * efi_$guid_$varname = (type)value
+ *
+ * For example:
+ *
+ * efi_8be4df6193ca11d2aa0d00e098032b8c_OsIndicationsSupported=
+ * "(u64)0"
+ * efi_f3cc021b90a3486683fbe8b6461fc2f2_fdtpath=
+ * "(string)qcom/apq8016-sbc.dtb"
+ *
+ * Possible types:
+ *
+ * + string - raw string (TODO automatically converted to utf16?)
+ * + u64 - hex string encoding 64b value
+ *
+ * TODO add other types as needed.
+ *
+ * TODO we could include attributes in the value string, ie. something
+ * like "(ro,boot)(string)qcom/apq8016-sbc.dtb"
+ *
+ * TODO we could at least provide read-only access to ->get_variable()
+ * and friends by snapshot'ing the variables at detach time and having
+ * alternate versions of ->get_variable() and ->get_next_variable()
+ * in efi_runtime section.
+ */
+
+#define MAX_VAR_NAME 31
+#define MAX_NATIVE_VAR_NAME (strlen("efi_xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx_") +
MAX_VAR_NAME)
+
+static int hex(unsigned char ch)
+{
+ if (ch >= 'a' && ch <= 'f')
+ return ch-'a'+10;
+ if (ch >= '0' && ch <= '9')
+ return ch-'0';
+ if (ch >= 'A' && ch <= 'F')
+ return ch-'A'+10;
+ return -1;
+}
+
+static const char * hex2mem(u8 *mem, const char *hexstr, int count)
+{
+ memset(mem, 0, count/2);
+
+ do {
+ int nibble;
+
+ *mem = 0;
+
+ if (!count || !*hexstr)
+ break;
+
+ nibble = hex(*hexstr);
+ if (nibble < 0)
+ break;
+
+ *mem = nibble;
+ count--;
+ hexstr++;
+
+ if (!count || !*hexstr)
+ break;
+
+ nibble = hex(*hexstr);
+ if (nibble < 0)
+ break;
+
+ *mem = (*mem << 4) | nibble;
+ count--;
+ hexstr++;
+ mem++;
+
+ } while (1);
+
+ if (*hexstr)
+ return hexstr;
+
+ return NULL;
+}
+
+static char * mem2hex(char *hexstr, const u8 *mem, int count)
+{
+ static const char hexchars[] = "0123456789abcdef";
+
+ while (count-- > 0) {
+ u8 ch = *mem++;
+ *hexstr++ = hexchars[ch >> 4];
+ *hexstr++ = hexchars[ch & 0xf];
+ }
+
+ return hexstr;
+}
+
+/* TODO this ends up byte-swapping the GUID compared to what one might
+ * expect, so:
+ *
+ * efi_61dfe48bca93d211aa0d00e098032b8c_OsIndicationsSupported
+ *
+ * instead of
+ *
+ * efi_8be4df6193ca11d2aa0d00e098032b8c_OsIndicationsSupported
+ *
+ * possibly make logic smarter in converting efi<->native
+ */
+
+static efi_status_t efi_to_native(char *native, s16 *variable_name,
+ efi_guid_t *vendor)
+{
+ size_t len;
+
+ len = utf16_strlen((u16 *)variable_name);
+ if (len >= MAX_VAR_NAME)
+ return EFI_DEVICE_ERROR;
+
+ native += sprintf(native, "efi_");
+ native = mem2hex(native, vendor->b, sizeof(vendor->b));
+ native += sprintf(native, "_");
+ native = (char *)utf16_to_utf8((u8 *)native, (u16 *)variable_name,
len);
+ *native = '\0';
+
+ return EFI_SUCCESS;
+}
+
+
+static const char * prefix(const char *str, const char *prefix)
+{
+ while (*str && *prefix) {
+ if (*str != *prefix)
+ break;
+ str++;
+ prefix++;
+ }
+
+ if (*prefix)
+ return NULL;
+
+ return str;
+}
+
+
+/*
http://wiki.phoenix.com/wiki/index.php/EFI_RUNTIME_SERVICES#GetVariable.28.29 */
+efi_status_t EFIAPI efi_get_variable(s16 *variable_name,
+ efi_guid_t *vendor, u32 *attributes,
+ unsigned long *data_size, void *data)
+{
+ char native_name[MAX_NATIVE_VAR_NAME + 1];
+ efi_status_t ret;
+ unsigned long in_size;
+ const char *val, *s;
+
+ EFI_ENTRY("%p %p %p %p %p", variable_name, vendor, attributes,
+ data_size, data);
+
+ if (!variable_name || !vendor || !data_size)
+ return EFI_EXIT(EFI_INVALID_PARAMETER);
+
+ ret = efi_to_native(native_name, variable_name, vendor);
+ if (ret)
+ return EFI_EXIT(ret);
+
+ debug("%s: get '%s'\n", __func__, native_name);
+
+ val = getenv(native_name);
+ if (!val)
+ return EFI_EXIT(EFI_NOT_FOUND);
+
+ in_size = *data_size;
+
+ if ((s = prefix(val, "(u64)"))) {
+ *data_size = sizeof(u64);
+
+ if (in_size < sizeof(u64))
+ return EFI_EXIT(EFI_BUFFER_TOO_SMALL);
+
+ if (!data)
+ return EFI_EXIT(EFI_INVALID_PARAMETER);
+
+ if (hex2mem(data, s, 16))
+ return EFI_EXIT(EFI_DEVICE_ERROR);
+
+ debug("%s: got value: %llu\n", __func__, *(u64 *)data);
+ } else if ((s = prefix(val, "(string)"))) {
+ /* TODO should string's be converted to utf16? Or maybe if
+ * string isn't really a thing in efi, this should be (utf8)
+ * (and (utf16)?) and (raw%d), with the former being (in the
+ * land of u-boot) ascii strings converted to utf8/utf16 and
+ * the latter just being an arbitrary hex encoded value??
+ */
+ return EFI_EXIT(EFI_DEVICE_ERROR);
+ } else {
+ debug("%s: invalid value: '%s'\n", __func__, val);
+ return EFI_EXIT(EFI_DEVICE_ERROR);
+ }
+ // TODO other types?
+
+ // TODO support attributes
+ if (attributes)
+ *attributes = EFI_VARIABLE_BOOTSERVICE_ACCESS;
+
+ return EFI_EXIT(EFI_SUCCESS);
+}
+
+/*
http://wiki.phoenix.com/wiki/index.php/EFI_RUNTIME_SERVICES#GetNextVariableName.28.29
*/
+efi_status_t EFIAPI efi_get_next_variable(
+ unsigned long *variable_name_size,
+ s16 *variable_name, efi_guid_t *vendor)
+{
+ EFI_ENTRY("%p %p %p", variable_name_size, variable_name, vendor);
+
+ return EFI_EXIT(EFI_DEVICE_ERROR);
+}
+
+/*
http://wiki.phoenix.com/wiki/index.php/EFI_RUNTIME_SERVICES#SetVariable.28.29 */
+efi_status_t EFIAPI efi_set_variable(s16 *variable_name,
+ efi_guid_t *vendor, u32 attributes,
+ unsigned long data_size, void *data)
+{
+ EFI_ENTRY("%p %p %x %lu %p", variable_name, vendor, attributes,
+ data_size, data);
+
+ return EFI_EXIT(EFI_DEVICE_ERROR);
+}
--
2.9.4
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