efi/libstub: Add a basic printf implementation
authorArvind Sankar <nivedita@alum.mit.edu>
Mon, 18 May 2020 19:06:56 +0000 (15:06 -0400)
committerArd Biesheuvel <ardb@kernel.org>
Tue, 19 May 2020 08:30:31 +0000 (10:30 +0200)
Copy vsprintf from arch/x86/boot/printf.c to get a simple printf
implementation.

Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Link: https://lore.kernel.org/r/20200518190716.751506-5-nivedita@alum.mit.edu
[ardb: add some missing braces in if...else clauses]
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
drivers/firmware/efi/libstub/Makefile
drivers/firmware/efi/libstub/efi-stub-helper.c
drivers/firmware/efi/libstub/efistub.h
drivers/firmware/efi/libstub/vsprintf.c [new file with mode: 0644]

index e5a49dc..fb34c9d 100644 (file)
@@ -44,7 +44,7 @@ KCOV_INSTRUMENT                       := n
 lib-y                          := efi-stub-helper.o gop.o secureboot.o tpm.o \
                                   file.o mem.o random.o randomalloc.o pci.o \
                                   skip_spaces.o lib-cmdline.o lib-ctype.o \
-                                  alignedmem.o relocate.o
+                                  alignedmem.o relocate.o vsprintf.o
 
 # include the stub's generic dependencies from lib/ when building for ARM/arm64
 efi-deps-y := fdt_rw.c fdt_ro.c fdt_wip.c fdt.c fdt_empty_tree.c fdt_sw.c
index 3cf506a..56b3b84 100644 (file)
@@ -7,6 +7,8 @@
  * Copyright 2011 Intel Corporation; author Matt Fleming
  */
 
+#include <stdarg.h>
+
 #include <linux/efi.h>
 #include <linux/kernel.h>
 #include <asm/efi.h>
@@ -51,6 +53,21 @@ void efi_puts(const char *str)
        }
 }
 
+int efi_printk(const char *fmt, ...)
+{
+       char printf_buf[256];
+       va_list args;
+       int printed;
+
+       va_start(args, fmt);
+       printed = vsprintf(printf_buf, fmt, args);
+       va_end(args);
+
+       efi_puts(printf_buf);
+
+       return printed;
+}
+
 /*
  * Parse the ASCII string 'cmdline' for EFI options, denoted by the efi=
  * option, e.g. efi=nochunk.
index 4f57611..caa7dcc 100644 (file)
@@ -3,6 +3,7 @@
 #ifndef _DRIVERS_FIRMWARE_EFI_EFISTUB_H
 #define _DRIVERS_FIRMWARE_EFI_EFISTUB_H
 
+#include <linux/compiler.h>
 #include <linux/efi.h>
 #include <linux/kernel.h>
 #include <linux/types.h>
@@ -632,6 +633,8 @@ void *get_efi_config_table(efi_guid_t guid);
 void efi_char16_puts(efi_char16_t *);
 void efi_puts(const char *str);
 
+__printf(1, 2) int efi_printk(char const *fmt, ...);
+
 void efi_free(unsigned long size, unsigned long addr);
 
 char *efi_convert_cmdline(efi_loaded_image_t *image, int *cmd_line_len,
diff --git a/drivers/firmware/efi/libstub/vsprintf.c b/drivers/firmware/efi/libstub/vsprintf.c
new file mode 100644 (file)
index 0000000..bb62d37
--- /dev/null
@@ -0,0 +1,299 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* -*- linux-c -*- ------------------------------------------------------- *
+ *
+ *   Copyright (C) 1991, 1992 Linus Torvalds
+ *   Copyright 2007 rPath, Inc. - All Rights Reserved
+ *
+ * ----------------------------------------------------------------------- */
+
+/*
+ * Oh, it's a waste of space, but oh-so-yummy for debugging.  This
+ * version of printf() does not include 64-bit support.  "Live with
+ * it."
+ *
+ */
+
+#include <stdarg.h>
+
+#include <linux/compiler.h>
+#include <linux/ctype.h>
+#include <linux/string.h>
+
+static int skip_atoi(const char **s)
+{
+       int i = 0;
+
+       while (isdigit(**s))
+               i = i * 10 + *((*s)++) - '0';
+       return i;
+}
+
+#define ZEROPAD        1               /* pad with zero */
+#define SIGN   2               /* unsigned/signed long */
+#define PLUS   4               /* show plus */
+#define SPACE  8               /* space if plus */
+#define LEFT   16              /* left justified */
+#define SMALL  32              /* Must be 32 == 0x20 */
+#define SPECIAL        64              /* 0x */
+
+#define __do_div(n, base) ({ \
+int __res; \
+__res = ((unsigned long) n) % (unsigned) base; \
+n = ((unsigned long) n) / (unsigned) base; \
+__res; })
+
+static char *number(char *str, long num, int base, int size, int precision,
+                   int type)
+{
+       /* we are called with base 8, 10 or 16, only, thus don't need "G..."  */
+       static const char digits[16] = "0123456789ABCDEF"; /* "GHIJKLMNOPQRSTUVWXYZ"; */
+
+       char tmp[66];
+       char c, sign, locase;
+       int i;
+
+       /* locase = 0 or 0x20. ORing digits or letters with 'locase'
+        * produces same digits or (maybe lowercased) letters */
+       locase = (type & SMALL);
+       if (type & LEFT)
+               type &= ~ZEROPAD;
+       if (base < 2 || base > 16)
+               return NULL;
+       c = (type & ZEROPAD) ? '0' : ' ';
+       sign = 0;
+       if (type & SIGN) {
+               if (num < 0) {
+                       sign = '-';
+                       num = -num;
+                       size--;
+               } else if (type & PLUS) {
+                       sign = '+';
+                       size--;
+               } else if (type & SPACE) {
+                       sign = ' ';
+                       size--;
+               }
+       }
+       if (type & SPECIAL) {
+               if (base == 16)
+                       size -= 2;
+               else if (base == 8)
+                       size--;
+       }
+       i = 0;
+       if (num == 0)
+               tmp[i++] = '0';
+       else
+               while (num != 0)
+                       tmp[i++] = (digits[__do_div(num, base)] | locase);
+       if (i > precision)
+               precision = i;
+       size -= precision;
+       if (!(type & (ZEROPAD + LEFT)))
+               while (size-- > 0)
+                       *str++ = ' ';
+       if (sign)
+               *str++ = sign;
+       if (type & SPECIAL) {
+               if (base == 8) {
+                       *str++ = '0';
+               } else if (base == 16) {
+                       *str++ = '0';
+                       *str++ = ('X' | locase);
+               }
+       }
+       if (!(type & LEFT))
+               while (size-- > 0)
+                       *str++ = c;
+       while (i < precision--)
+               *str++ = '0';
+       while (i-- > 0)
+               *str++ = tmp[i];
+       while (size-- > 0)
+               *str++ = ' ';
+       return str;
+}
+
+int vsprintf(char *buf, const char *fmt, va_list args)
+{
+       int len;
+       unsigned long num;
+       int i, base;
+       char *str;
+       const char *s;
+
+       int flags;              /* flags to number() */
+
+       int field_width;        /* width of output field */
+       int precision;          /* min. # of digits for integers; max
+                                  number of chars for from string */
+       int qualifier;          /* 'h', 'l', or 'L' for integer fields */
+
+       for (str = buf; *fmt; ++fmt) {
+               if (*fmt != '%') {
+                       *str++ = *fmt;
+                       continue;
+               }
+
+               /* process flags */
+               flags = 0;
+             repeat:
+               ++fmt;          /* this also skips first '%' */
+               switch (*fmt) {
+               case '-':
+                       flags |= LEFT;
+                       goto repeat;
+               case '+':
+                       flags |= PLUS;
+                       goto repeat;
+               case ' ':
+                       flags |= SPACE;
+                       goto repeat;
+               case '#':
+                       flags |= SPECIAL;
+                       goto repeat;
+               case '0':
+                       flags |= ZEROPAD;
+                       goto repeat;
+               }
+
+               /* get field width */
+               field_width = -1;
+               if (isdigit(*fmt)) {
+                       field_width = skip_atoi(&fmt);
+               } else if (*fmt == '*') {
+                       ++fmt;
+                       /* it's the next argument */
+                       field_width = va_arg(args, int);
+                       if (field_width < 0) {
+                               field_width = -field_width;
+                               flags |= LEFT;
+                       }
+               }
+
+               /* get the precision */
+               precision = -1;
+               if (*fmt == '.') {
+                       ++fmt;
+                       if (isdigit(*fmt)) {
+                               precision = skip_atoi(&fmt);
+                       } else if (*fmt == '*') {
+                               ++fmt;
+                               /* it's the next argument */
+                               precision = va_arg(args, int);
+                       }
+                       if (precision < 0)
+                               precision = 0;
+               }
+
+               /* get the conversion qualifier */
+               qualifier = -1;
+               if (*fmt == 'h' || *fmt == 'l' || *fmt == 'L') {
+                       qualifier = *fmt;
+                       ++fmt;
+               }
+
+               /* default base */
+               base = 10;
+
+               switch (*fmt) {
+               case 'c':
+                       if (!(flags & LEFT))
+                               while (--field_width > 0)
+                                       *str++ = ' ';
+                       *str++ = (unsigned char)va_arg(args, int);
+                       while (--field_width > 0)
+                               *str++ = ' ';
+                       continue;
+
+               case 's':
+                       s = va_arg(args, char *);
+                       len = strnlen(s, precision);
+
+                       if (!(flags & LEFT))
+                               while (len < field_width--)
+                                       *str++ = ' ';
+                       for (i = 0; i < len; ++i)
+                               *str++ = *s++;
+                       while (len < field_width--)
+                               *str++ = ' ';
+                       continue;
+
+               case 'p':
+                       if (field_width == -1) {
+                               field_width = 2 * sizeof(void *);
+                               flags |= ZEROPAD;
+                       }
+                       str = number(str,
+                                    (unsigned long)va_arg(args, void *), 16,
+                                    field_width, precision, flags);
+                       continue;
+
+               case 'n':
+                       if (qualifier == 'l') {
+                               long *ip = va_arg(args, long *);
+                               *ip = (str - buf);
+                       } else {
+                               int *ip = va_arg(args, int *);
+                               *ip = (str - buf);
+                       }
+                       continue;
+
+               case '%':
+                       *str++ = '%';
+                       continue;
+
+                       /* integer number formats - set up the flags and "break" */
+               case 'o':
+                       base = 8;
+                       break;
+
+               case 'x':
+                       flags |= SMALL;
+                       fallthrough;
+               case 'X':
+                       base = 16;
+                       break;
+
+               case 'd':
+               case 'i':
+                       flags |= SIGN;
+                       fallthrough;
+               case 'u':
+                       break;
+
+               default:
+                       *str++ = '%';
+                       if (*fmt)
+                               *str++ = *fmt;
+                       else
+                               --fmt;
+                       continue;
+               }
+               if (qualifier == 'l') {
+                       num = va_arg(args, unsigned long);
+               } else if (qualifier == 'h') {
+                       num = (unsigned short)va_arg(args, int);
+                       if (flags & SIGN)
+                               num = (short)num;
+               } else if (flags & SIGN) {
+                       num = va_arg(args, int);
+               } else {
+                       num = va_arg(args, unsigned int);
+               }
+               str = number(str, num, base, field_width, precision, flags);
+       }
+       *str = '\0';
+       return str - buf;
+}
+
+int sprintf(char *buf, const char *fmt, ...)
+{
+       va_list args;
+       int i;
+
+       va_start(args, fmt);
+       i = vsprintf(buf, fmt, args);
+       va_end(args);
+       return i;
+}