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.28.2... */ +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#GetNextVariableN... */ +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.28.2... */ +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); +}