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1// SPDX-License-Identifier: GPL-2.02 3#include <linux/stdarg.h>4 5#include <linux/ctype.h>6#include <linux/efi.h>7#include <linux/kernel.h>8#include <linux/printk.h> /* For CONSOLE_LOGLEVEL_* */9#include <asm/efi.h>10#include <asm/setup.h>11 12#include "efistub.h"13 14int efi_loglevel = CONSOLE_LOGLEVEL_DEFAULT;15 16/**17 * efi_char16_puts() - Write a UCS-2 encoded string to the console18 * @str: UCS-2 encoded string19 */20void efi_char16_puts(efi_char16_t *str)21{22 efi_call_proto(efi_table_attr(efi_system_table, con_out),23 output_string, str);24}25 26static27u32 utf8_to_utf32(const u8 **s8)28{29 u32 c32;30 u8 c0, cx;31 size_t clen, i;32 33 c0 = cx = *(*s8)++;34 /*35 * The position of the most-significant 0 bit gives us the length of36 * a multi-octet encoding.37 */38 for (clen = 0; cx & 0x80; ++clen)39 cx <<= 1;40 /*41 * If the 0 bit is in position 8, this is a valid single-octet42 * encoding. If the 0 bit is in position 7 or positions 1-3, the43 * encoding is invalid.44 * In either case, we just return the first octet.45 */46 if (clen < 2 || clen > 4)47 return c0;48 /* Get the bits from the first octet. */49 c32 = cx >> clen--;50 for (i = 0; i < clen; ++i) {51 /* Trailing octets must have 10 in most significant bits. */52 cx = (*s8)[i] ^ 0x80;53 if (cx & 0xc0)54 return c0;55 c32 = (c32 << 6) | cx;56 }57 /*58 * Check for validity:59 * - The character must be in the Unicode range.60 * - It must not be a surrogate.61 * - It must be encoded using the correct number of octets.62 */63 if (c32 > 0x10ffff ||64 (c32 & 0xf800) == 0xd800 ||65 clen != (c32 >= 0x80) + (c32 >= 0x800) + (c32 >= 0x10000))66 return c0;67 *s8 += clen;68 return c32;69}70 71/**72 * efi_puts() - Write a UTF-8 encoded string to the console73 * @str: UTF-8 encoded string74 */75void efi_puts(const char *str)76{77 efi_char16_t buf[128];78 size_t pos = 0, lim = ARRAY_SIZE(buf);79 const u8 *s8 = (const u8 *)str;80 u32 c32;81 82 while (*s8) {83 if (*s8 == '\n')84 buf[pos++] = L'\r';85 c32 = utf8_to_utf32(&s8);86 if (c32 < 0x10000) {87 /* Characters in plane 0 use a single word. */88 buf[pos++] = c32;89 } else {90 /*91 * Characters in other planes encode into a surrogate92 * pair.93 */94 buf[pos++] = (0xd800 - (0x10000 >> 10)) + (c32 >> 10);95 buf[pos++] = 0xdc00 + (c32 & 0x3ff);96 }97 if (*s8 == '\0' || pos >= lim - 2) {98 buf[pos] = L'\0';99 efi_char16_puts(buf);100 pos = 0;101 }102 }103}104 105/**106 * efi_printk() - Print a kernel message107 * @fmt: format string108 *109 * The first letter of the format string is used to determine the logging level110 * of the message. If the level is less then the current EFI logging level, the111 * message is suppressed. The message will be truncated to 255 bytes.112 *113 * Return: number of printed characters114 */115int efi_printk(const char *fmt, ...)116{117 char printf_buf[256];118 va_list args;119 int printed;120 int loglevel = printk_get_level(fmt);121 122 switch (loglevel) {123 case '0' ... '9':124 loglevel -= '0';125 break;126 default:127 /*128 * Use loglevel -1 for cases where we just want to print to129 * the screen.130 */131 loglevel = -1;132 break;133 }134 135 if (loglevel >= efi_loglevel)136 return 0;137 138 if (loglevel >= 0)139 efi_puts("EFI stub: ");140 141 fmt = printk_skip_level(fmt);142 143 va_start(args, fmt);144 printed = vsnprintf(printf_buf, sizeof(printf_buf), fmt, args);145 va_end(args);146 147 efi_puts(printf_buf);148 if (printed >= sizeof(printf_buf)) {149 efi_puts("[Message truncated]\n");150 return -1;151 }152 153 return printed;154}155