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// SPDX-License-Identifier: GPL-2.0+
/*
* Hello world EFI application
*
* Copyright 2020, Heinrich Schuchardt <xypron.glpk@gmx.de>
*
* This test program is used to test the invocation of an EFI application.
* It writes
*
* * a greeting
* * the firmware's UEFI version
* * the installed configuration tables
* * the boot device's device path and the file path
*
* to the console.
*/
#include <efi_api.h>
static const efi_guid_t loaded_image_guid = EFI_LOADED_IMAGE_PROTOCOL_GUID;
static const efi_guid_t device_path_to_text_protocol_guid =
EFI_DEVICE_PATH_TO_TEXT_PROTOCOL_GUID;
static const efi_guid_t device_path_guid = EFI_DEVICE_PATH_PROTOCOL_GUID;
static const efi_guid_t fdt_guid = EFI_FDT_GUID;
static const efi_guid_t acpi_guid = EFI_ACPI_TABLE_GUID;
static const efi_guid_t smbios_guid = SMBIOS_TABLE_GUID;
static struct efi_system_table *systable;
static struct efi_boot_services *boottime;
static struct efi_simple_text_output_protocol *con_out;
/*
* Print an unsigned 32bit value as decimal number to an u16 string
*
* @value: value to be printed
* @buf: pointer to buffer address
* on return position of terminating zero word
*/
static void uint2dec(u32 value, u16 **buf)
{
u16 *pos = *buf;
int i;
u16 c;
u64 f;
/*
* Increment by .5 and multiply with
* (2 << 60) / 1,000,000,000 = 0x44B82FA0.9B5A52CC
* to move the first digit to bit 60-63.
*/
f = 0x225C17D0;
f += (0x9B5A52DULL * value) >> 28;
f += 0x44B82FA0ULL * value;
for (i = 0; i < 10; ++i) {
/* Write current digit */
c = f >> 60;
if (c || pos != *buf)
*pos++ = c + '0';
/* Eliminate current digit */
f &= 0xfffffffffffffff;
/* Get next digit */
f *= 0xaULL;
}
if (pos == *buf)
*pos++ = '0';
*pos = 0;
*buf = pos;
}
/**
* print_uefi_revision() - print UEFI revision number
*/
static void print_uefi_revision(void)
{
u16 rev[13] = {0};
u16 *buf = rev;
u16 digit;
uint2dec(systable->hdr.revision >> 16, &buf);
*buf++ = '.';
uint2dec(systable->hdr.revision & 0xffff, &buf);
/* Minor revision is only to be shown if non-zero */
digit = *--buf;
if (digit == '0') {
*buf = 0;
} else {
*buf++ = '.';
*buf = digit;
}
con_out->output_string(con_out, u"Running on UEFI ");
con_out->output_string(con_out, rev);
con_out->output_string(con_out, u"\r\n");
}
/**
* print_config_tables() - print configuration tables
*/
static void print_config_tables(void)
{
efi_uintn_t i;
/* Find configuration tables */
for (i = 0; i < systable->nr_tables; ++i) {
if (!memcmp(&systable->tables[i].guid, &fdt_guid,
sizeof(efi_guid_t)))
con_out->output_string
(con_out, u"Have device tree\r\n");
if (!memcmp(&systable->tables[i].guid, &acpi_guid,
sizeof(efi_guid_t)))
con_out->output_string
(con_out, u"Have ACPI 2.0 table\r\n");
if (!memcmp(&systable->tables[i].guid, &smbios_guid,
sizeof(efi_guid_t)))
con_out->output_string
(con_out, u"Have SMBIOS table\r\n");
}
}
/**
* print_load_options() - print load options
*
* @systable: system table
* @con_out: simple text output protocol
*/
static void print_load_options(struct efi_loaded_image *loaded_image)
{
/* Output the load options */
con_out->output_string(con_out, u"Load options: ");
if (loaded_image->load_options_size && loaded_image->load_options)
con_out->output_string(con_out,
(u16 *)loaded_image->load_options);
else
con_out->output_string(con_out, u"<none>");
con_out->output_string(con_out, u"\r\n");
}
/**
* print_device_path() - print device path
*
* @device_path: device path to print
* @dp2txt: device path to text protocol
*/
static
efi_status_t print_device_path(struct efi_device_path *device_path,
struct efi_device_path_to_text_protocol *dp2txt)
{
u16 *string;
efi_status_t ret;
if (!device_path) {
con_out->output_string(con_out, u"<none>\r\n");
return EFI_SUCCESS;
}
string = dp2txt->convert_device_path_to_text(device_path, true, false);
if (!string) {
con_out->output_string
(con_out, u"Cannot convert device path to text\r\n");
return EFI_OUT_OF_RESOURCES;
}
con_out->output_string(con_out, string);
con_out->output_string(con_out, u"\r\n");
ret = boottime->free_pool(string);
if (ret != EFI_SUCCESS) {
con_out->output_string(con_out, u"Cannot free pool memory\r\n");
return ret;
}
return EFI_SUCCESS;
}
/**
* efi_main() - entry point of the EFI application.
*
* @handle: handle of the loaded image
* @systab: system table
* Return: status code
*/
efi_status_t EFIAPI efi_main(efi_handle_t handle,
struct efi_system_table *systab)
{
struct efi_loaded_image *loaded_image;
struct efi_device_path_to_text_protocol *device_path_to_text;
struct efi_device_path *device_path;
efi_status_t ret;
systable = systab;
boottime = systable->boottime;
con_out = systable->con_out;
/* UEFI requires CR LF */
con_out->output_string(con_out, u"Hello, world!\r\n");
print_uefi_revision();
print_config_tables();
/* Get the loaded image protocol */
ret = boottime->open_protocol(handle, &loaded_image_guid,
(void **)&loaded_image, NULL, NULL,
EFI_OPEN_PROTOCOL_GET_PROTOCOL);
if (ret != EFI_SUCCESS) {
con_out->output_string
(con_out, u"Cannot open loaded image protocol\r\n");
goto out;
}
print_load_options(loaded_image);
/* Get the device path to text protocol */
ret = boottime->locate_protocol(&device_path_to_text_protocol_guid,
NULL, (void **)&device_path_to_text);
if (ret != EFI_SUCCESS) {
con_out->output_string
(con_out, u"Cannot open device path to text protocol\r\n");
goto out;
}
con_out->output_string(con_out, u"File path: ");
ret = print_device_path(loaded_image->file_path, device_path_to_text);
if (ret != EFI_SUCCESS)
goto out;
if (!loaded_image->device_handle) {
con_out->output_string
(con_out, u"Missing device handle\r\n");
goto out;
}
ret = boottime->open_protocol(loaded_image->device_handle,
&device_path_guid,
(void **)&device_path, NULL, NULL,
EFI_OPEN_PROTOCOL_GET_PROTOCOL);
if (ret != EFI_SUCCESS) {
con_out->output_string
(con_out, u"Missing device path for device handle\r\n");
goto out;
}
con_out->output_string(con_out, u"Boot device: ");
ret = print_device_path(device_path, device_path_to_text);
if (ret != EFI_SUCCESS)
goto out;
out:
boottime->exit(handle, ret, 0, NULL);
/* We should never arrive here */
return ret;
}
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