diff options
Diffstat (limited to 'drivers/firmware/efi/libstub/printk.c')
-rw-r--r-- | drivers/firmware/efi/libstub/printk.c | 154 |
1 files changed, 154 insertions, 0 deletions
diff --git a/drivers/firmware/efi/libstub/printk.c b/drivers/firmware/efi/libstub/printk.c new file mode 100644 index 0000000000..3a67a2cea7 --- /dev/null +++ b/drivers/firmware/efi/libstub/printk.c @@ -0,0 +1,154 @@ +// 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; +} |