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// SPDX-License-Identifier: GPL-2.0
#include <linux/stdarg.h>
#include <linux/ctype.h>
#include <linux/efi.h>
#include <linux/kernel.h>
#include <linux/printk.h> /* For CONSOLE_LOGLEVEL_* */
#include <asm/efi.h>
#include <asm/setup.h>
#include "efistub.h"
int efi_loglevel = CONSOLE_LOGLEVEL_DEFAULT;
/**
* efi_char16_puts() - Write a UCS-2 encoded string to the console
* @str: UCS-2 encoded string
*/
void efi_char16_puts(efi_char16_t *str)
{
efi_call_proto(efi_table_attr(efi_system_table, con_out),
output_string, str);
}
static
u32 utf8_to_utf32(const u8 **s8)
{
u32 c32;
u8 c0, cx;
size_t clen, i;
c0 = cx = *(*s8)++;
/*
* The position of the most-significant 0 bit gives us the length of
* a multi-octet encoding.
*/
for (clen = 0; cx & 0x80; ++clen)
cx <<= 1;
/*
* If the 0 bit is in position 8, this is a valid single-octet
* encoding. If the 0 bit is in position 7 or positions 1-3, the
* encoding is invalid.
* In either case, we just return the first octet.
*/
if (clen < 2 || clen > 4)
return c0;
/* Get the bits from the first octet. */
c32 = cx >> clen--;
for (i = 0; i < clen; ++i) {
/* Trailing octets must have 10 in most significant bits. */
cx = (*s8)[i] ^ 0x80;
if (cx & 0xc0)
return c0;
c32 = (c32 << 6) | cx;
}
/*
* Check for validity:
* - The character must be in the Unicode range.
* - It must not be a surrogate.
* - It must be encoded using the correct number of octets.
*/
if (c32 > 0x10ffff ||
(c32 & 0xf800) == 0xd800 ||
clen != (c32 >= 0x80) + (c32 >= 0x800) + (c32 >= 0x10000))
return c0;
*s8 += clen;
return c32;
}
/**
* efi_puts() - Write a UTF-8 encoded string to the console
* @str: UTF-8 encoded string
*/
void efi_puts(const char *str)
{
efi_char16_t buf[128];
size_t pos = 0, lim = ARRAY_SIZE(buf);
const u8 *s8 = (const u8 *)str;
u32 c32;
while (*s8) {
if (*s8 == '\n')
buf[pos++] = L'\r';
c32 = utf8_to_utf32(&s8);
if (c32 < 0x10000) {
/* Characters in plane 0 use a single word. */
buf[pos++] = c32;
} else {
/*
* Characters in other planes encode into a surrogate
* pair.
*/
buf[pos++] = (0xd800 - (0x10000 >> 10)) + (c32 >> 10);
buf[pos++] = 0xdc00 + (c32 & 0x3ff);
}
if (*s8 == '\0' || pos >= lim - 2) {
buf[pos] = L'\0';
efi_char16_puts(buf);
pos = 0;
}
}
}
/**
* efi_printk() - Print a kernel message
* @fmt: format string
*
* The first letter of the format string is used to determine the logging level
* of the message. If the level is less then the current EFI logging level, the
* message is suppressed. The message will be truncated to 255 bytes.
*
* Return: number of printed characters
*/
int efi_printk(const char *fmt, ...)
{
char printf_buf[256];
va_list args;
int printed;
int loglevel = printk_get_level(fmt);
switch (loglevel) {
case '0' ... '9':
loglevel -= '0';
break;
default:
/*
* Use loglevel -1 for cases where we just want to print to
* the screen.
*/
loglevel = -1;
break;
}
if (loglevel >= efi_loglevel)
return 0;
if (loglevel >= 0)
efi_puts("EFI stub: ");
fmt = printk_skip_level(fmt);
va_start(args, fmt);
printed = vsnprintf(printf_buf, sizeof(printf_buf), fmt, args);
va_end(args);
efi_puts(printf_buf);
if (printed >= sizeof(printf_buf)) {
efi_puts("[Message truncated]\n");
return -1;
}
return printed;
}
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