This change adds support for reading enviroment variables. To do so it
introduces a new GUID: 97ef3e03-7329-4a6a-b9ba-6c1fdcc5f823 that the
user needs to provide when setting enviroment variables. For example,
to set the path to the fdt a user can execute:
In addition, this change add support for reading the fdt into memory
and providing a pointer to the test through efi_bootinfo_t.
Signed-off-by: Nikos Nikoleris <nikos.nikoleris@xxxxxxx>
---
lib/linux/efi.h | 101 ++++++++++++++++++++++++++++++++++++++++
lib/efi.h | 12 +++++
lib/efi.c | 120 ++++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 233 insertions(+)
diff --git a/lib/linux/efi.h b/lib/linux/efi.h
index 9a1cf87b..bb6d5a85 100644
--- a/lib/linux/efi.h
+++ b/lib/linux/efi.h
@@ -12,6 +12,7 @@
#define BITS_PER_LONG 64
+#define EFI_ERROR(a) (((int64_t) a) < 0)
#define EFI_SUCCESS 0
#define EFI_LOAD_ERROR ( 1 | (1UL << (BITS_PER_LONG-1)))
#define EFI_INVALID_PARAMETER ( 2 | (1UL << (BITS_PER_LONG-1)))
@@ -436,6 +437,106 @@ struct efi_loaded_image_64 {
efi_status_t (__efiapi * unload)(efi_handle_t image_handle);
};
+
+typedef struct _efi_simple_file_system_protocol efi_simple_file_system_protocol_t;
+typedef struct _efi_file_protocol efi_file_protocol_t;
+typedef efi_simple_file_system_protocol_t efi_file_io_interface_t;
+typedef efi_file_protocol_t efi_file_t;
+
+typedef efi_status_t efi_simple_file_system_protocol_open_volume(
+ efi_simple_file_system_protocol_t *this,
+ efi_file_protocol_t **root);
+
+#define EFI_SIMPLE_FILE_SYSTEM_PROTOCOL_GUID EFI_GUID(0x964e5b22, 0x6459, 0x11d2, 0x8e, 0x39, 0x0, 0xa0, 0xc9, 0x69, 0x72, 0x3b)
+
+struct _efi_simple_file_system_protocol {
+ uint64_t revision;
+ efi_simple_file_system_protocol_open_volume __efiapi *open_volume;
+};
+
+/* Open modes */
+#define EFI_FILE_MODE_READ 0x0000000000000001ULL
+#define EFI_FILE_MODE_WRITE 0x0000000000000002ULL
+#define EFI_FILE_MODE_CREATE 0x8000000000000000ULL
+
+typedef efi_status_t efi_file_open(efi_file_protocol_t *this,
+ efi_file_protocol_t **new_handle,
+ efi_char16_t *file_name,
+ uint64_t open_mode,
+ uint64_t attributes);
+typedef efi_status_t efi_file_close(efi_file_protocol_t *this);
+typedef efi_status_t efi_file_delete(efi_file_protocol_t *this);
+typedef efi_status_t efi_file_read(efi_file_protocol_t *this,
+ uint64_t *buffer_size,
+ void *buffer);
+typedef efi_status_t efi_file_write(efi_file_protocol_t *this,
+ uint64_t *buffer_size,
+ void *buffer);
+typedef efi_status_t efi_file_set_position(efi_file_protocol_t *this,
+ uint64_t position);
+typedef efi_status_t efi_file_get_position(efi_file_protocol_t *this,
+ uint64_t *position);
+typedef efi_status_t efi_file_get_info(efi_file_protocol_t *this,
+ efi_guid_t *information_type,
+ uint64_t *buffer_size,
+ void *buffer);
+typedef efi_status_t efi_file_set_info(efi_file_protocol_t *this,
+ efi_guid_t *information_type,
+ uint64_t *buffer_size,
+ void *buffer);
+typedef efi_status_t efi_file_flush(efi_file_protocol_t *this);
+
+typedef struct {
+ efi_event_t event;
+ efi_status_t status;
+ uint64_t buffer_size;
+ void *buffer;
+} efi_file_io_open_t;
+
+typedef efi_status_t efi_file_open_ex(efi_file_protocol_t *this,
+ efi_file_protocol_t **new_handle,
+ efi_char16_t *file_name,
+ uint64_t open_mode,
+ uint64_t attributes,
+ efi_file_io_open_t *token);
+typedef efi_status_t efi_file_read_ex(efi_file_protocol_t *this,
+ efi_file_io_open_t *token);
+typedef efi_status_t efi_file_write_ex(efi_file_protocol_t *this,
+ efi_file_io_open_t *token);
+typedef efi_status_t efi_file_flush_ex(efi_file_protocol_t *this,
+ efi_file_io_open_t *token);
+
+struct _efi_file_protocol {
+ uint64_t revision;
+ efi_file_open __efiapi *open;
+ efi_file_close __efiapi *close;
+ efi_file_delete __efiapi *delete;
+ efi_file_read __efiapi *read;
+ efi_file_write __efiapi *write;
+ efi_file_get_position __efiapi *get_position;
+ efi_file_set_position __efiapi *set_position;
+ efi_file_get_info __efiapi *get_info;
+ efi_file_set_info __efiapi *set_info;
+ efi_file_flush __efiapi *flush;
+ efi_file_open_ex __efiapi *open_ex;
+ efi_file_read_ex __efiapi *read_ex;
+ efi_file_write_ex __efiapi *write_ex;
+ efi_file_flush_ex __efiapi *flush_ex;
+};
+
+#define EFI_FILE_INFO_ID EFI_GUID(0x9576e92, 0x6d3f, 0x11d2, 0x8e, 0x39, 0x0, 0xa0, 0xc9, 0x69, 0x72, 0x3b )
+
+typedef struct {
+ uint64_t size;
+ uint64_t file_size;
+ uint64_t physical_size;
+ efi_time_t create_time;
+ efi_time_t last_access_time;
+ efi_time_t modification_time;
+ uint64_t attributes;
+ efi_char16_t file_name[1];
+} efi_file_info_t;
+
#define efi_bs_call(func, ...) efi_system_table->boottime->func(__VA_ARGS__)
#define efi_rs_call(func, ...) efi_system_table->runtime->func(__VA_ARGS__)
diff --git a/lib/efi.h b/lib/efi.h
index ce8b74d7..db46d450 100644
--- a/lib/efi.h
+++ b/lib/efi.h
@@ -11,6 +11,17 @@
#include "linux/efi.h"
#include <elf.h>
+/*
+ * Define a GUID that we can use to to pass environment variables.
+ *
+ * For example, to set the variable var to the value val via the EFI shell:
+ * # setvar env -guid 97ef3e03-7329-4a6a-b9ba-6c1fdcc5f823 -rt =L"val"
+ */
+#define EFI_VAR_GUID EFI_GUID(0x97ef3e03, 0x7329, 0x4a6a, 0xb9, 0xba, 0x6c, 0x1f, 0xdc, 0xc5, 0xf8, 0x23);
+
+/* Names of environment variables we can handle */
+#define ENV_VARNAME_DTBFILE L"fdtfile"
+
/*
* efi_bootinfo_t: stores EFI-related machine info retrieved before exiting EFI
* boot services, and is then used by setup_efi(). setup_efi() cannot retrieve
@@ -19,6 +30,7 @@
*/
typedef struct {
struct efi_boot_memmap mem_map;
+ const void *fdt;
} efi_bootinfo_t;
efi_status_t _relocate(long ldbase, Elf64_Dyn *dyn, efi_handle_t handle,
diff --git a/lib/efi.c b/lib/efi.c
index f524ec9b..2e127a40 100644
--- a/lib/efi.c
+++ b/lib/efi.c
@@ -173,6 +173,125 @@ static char *efi_convert_cmdline(struct efi_loaded_image_64 *image, int *cmd_lin
return (char *)cmdline_addr;
}
+/*
+ * Open the file and read it into a buffer.
+ */
+static void efi_load_image(efi_handle_t handle, struct efi_loaded_image_64 *image, void **data,
+ int *datasize, efi_char16_t *path_name)
+{
+ uint64_t buffer_size = sizeof(efi_file_info_t);
+ efi_file_info_t *file_info;
+ efi_file_io_interface_t *io_if;
+ efi_file_t *root, *file;
+ efi_status_t status;
+ efi_guid_t file_system_proto_guid = EFI_SIMPLE_FILE_SYSTEM_PROTOCOL_GUID;
+ efi_guid_t file_info_guid = EFI_FILE_INFO_ID;
+
+ /* Open the device */
+ status = efi_bs_call(handle_protocol, image->device_handle, &file_system_proto_guid,
+ (void **)&io_if);
+ if (status != EFI_SUCCESS)
+ return;
+
+ status = io_if->open_volume(io_if, &root);
+ if (status != EFI_SUCCESS)
+ return;
+
+ /* And then open the file */
+ status = root->open(root, &file, path_name, EFI_FILE_MODE_READ, 0);
+ if (status != EFI_SUCCESS) {
+ printf("Failed to open %ls - %lx\n", path_name, status);
+ assert(status == EFI_SUCCESS);
+ }
+
+ /* Find the file size in order to allocate the buffer */
+ status = efi_bs_call(allocate_pool, EFI_LOADER_DATA, buffer_size, (void **)&file_info);
+ if (status != EFI_SUCCESS)
+ return;
+
+ status = file->get_info(file, &file_info_guid, &buffer_size, file_info);
+ if (status == EFI_BUFFER_TOO_SMALL) {
+ efi_free_pool(file_info);
+ status = efi_bs_call(allocate_pool, EFI_LOADER_DATA, buffer_size, (void **)&file_info);
+ assert(file_info);
+ status = file->get_info(file, &file_info_guid, &buffer_size, file_info);
+ }
+ assert(status == EFI_SUCCESS);
+
+ buffer_size = file_info->file_size;
+
+ efi_free_pool(file_info);
+
+ status = efi_bs_call(allocate_pool, EFI_LOADER_DATA, buffer_size, (void **)data);
+ assert(*data);
+ /* Perform the actual read */
+ status = file->read(file, &buffer_size, *data);
+ if (status == EFI_BUFFER_TOO_SMALL) {
+ efi_free_pool(*data);
+ status = efi_bs_call(allocate_pool, EFI_LOADER_DATA, buffer_size, (void **)data);
+ status = file->read(file, &buffer_size, *data);
+ }
+ assert(status == EFI_SUCCESS);
+
+ *datasize = buffer_size;
+}
+
+static int efi_grow_buffer(efi_status_t *status, void **buffer, uint64_t buffer_size)
+{
+ int try_again;
+
+ if (!*buffer && buffer_size) {
+ *status = EFI_BUFFER_TOO_SMALL;
+ }
+
+ try_again = 0;
+ if (*status == EFI_BUFFER_TOO_SMALL) {
+ if (*buffer)
+ efi_free_pool(*buffer);
+
+ efi_bs_call(allocate_pool, EFI_LOADER_DATA, buffer_size, buffer);
+ if (*buffer) {
+ try_again = 1;
+ } else {
+ *status = EFI_OUT_OF_RESOURCES;
+ }
+ }
+
+ if (!try_again && EFI_ERROR(*status) && *buffer) {
+ efi_free_pool(*buffer);
+ *buffer = NULL;
+ }
+
+ return try_again;
+}
+
+static void* efi_get_var(efi_handle_t handle, struct efi_loaded_image_64 *image, efi_char16_t *var)
+{
+ efi_status_t status = EFI_SUCCESS;
+ void *val = NULL;
+ uint64_t val_size = 100;
+ efi_guid_t efi_var_guid = EFI_VAR_GUID;
+
+ while (efi_grow_buffer(&status, &val, val_size))
+ status = efi_rs_call(get_variable, var, &efi_var_guid, NULL, &val_size, val);
+
+ return val;
+}
+
+static void *efi_get_fdt(efi_handle_t handle, struct efi_loaded_image_64 *image)
+{
+ efi_char16_t var[] = ENV_VARNAME_DTBFILE;
+ efi_char16_t *val;
+ void *fdt = NULL;
+ int fdtsize;
+
+ val = efi_get_var(handle, image, var);
+ if (val)
+ efi_load_image(handle, image, &fdt, &fdtsize, val);
+
+ return fdt;
+}
+
efi_status_t efi_main(efi_handle_t handle, efi_system_table_t *sys_tab)
{
int ret;
@@ -211,6 +330,7 @@ efi_status_t efi_main(efi_handle_t handle, efi_system_table_t *sys_tab)
}
setup_args(cmdline_ptr);
+ efi_bootinfo.fdt = efi_get_fdt(handle, image);
/* Set up efi_bootinfo */
efi_bootinfo.mem_map.map = ↦
efi_bootinfo.mem_map.map_size = &map_size;
--
2.25.1
