target/linux/ipq806x/patches-5.4/0067-generic-Mangle-bootloader-s-kernel-arguments.patch

   1 From 71270226b14733a4b1f2cde58ea9265caa50b38d Mon Sep 17 00:00:00 2001
   2 From: Adrian Panella <ianchi74@outlook.com>
   3 Date: Thu, 9 Mar 2017 09:37:17 +0100
   4 Subject: [PATCH 67/69] generic: Mangle bootloader's kernel arguments
   5
   6 The command-line arguments provided by the boot loader will be
   7 appended to a new device tree property: bootloader-args.
   8 If there is a property "append-rootblock" in DT under /chosen
   9 and a root= option in bootloaders command line it will be parsed
  10 and added to DT bootargs with the form: <append-rootblock>XX.
  11 Only command line ATAG will be processed, the rest of the ATAGs
  12 sent by bootloader will be ignored.
  13 This is usefull in dual boot systems, to get the current root partition
  14 without afecting the rest of the system.
  15
  16 Signed-off-by: Adrian Panella <ianchi74@outlook.com>
  17 ---
  18  arch/arm/Kconfig                        | 11 +++++
  19  arch/arm/boot/compressed/atags_to_fdt.c | 72 ++++++++++++++++++++++++++++++++-
  20  init/main.c                             | 16 ++++++++
  21  3 files changed, 98 insertions(+), 1 deletion(-)
  22
  23 --- a/arch/arm/Kconfig
  24 +++ b/arch/arm/Kconfig
  25 @@ -1825,6 +1825,17 @@ config ARM_ATAG_DTB_COMPAT_CMDLINE_EXTEN
  26           The command-line arguments provided by the boot loader will be
  27           appended to the the device tree bootargs property.
  28
  29 +config ARM_ATAG_DTB_COMPAT_CMDLINE_MANGLE
  30 +       bool "Append rootblock parsing bootloader's kernel arguments"
  31 +       help
  32 +         The command-line arguments provided by the boot loader will be
  33 +         appended to a new device tree property: bootloader-args.
  34 +         If there is a property "append-rootblock" in DT under /chosen
  35 +         and a root= option in bootloaders command line it will be parsed
  36 +         and added to DT bootargs with the form: <append-rootblock>XX.
  37 +         Only command line ATAG will be processed, the rest of the ATAGs
  38 +         sent by bootloader will be ignored.
  39 +
  40  endchoice
  41
  42  config CMDLINE
  43 --- a/arch/arm/boot/compressed/atags_to_fdt.c
  44 +++ b/arch/arm/boot/compressed/atags_to_fdt.c
  45 @@ -4,6 +4,8 @@
  46
  47  #if defined(CONFIG_ARM_ATAG_DTB_COMPAT_CMDLINE_EXTEND)
  48  #define do_extend_cmdline 1
  49 +#elif defined(CONFIG_ARM_ATAG_DTB_COMPAT_CMDLINE_MANGLE)
  50 +#define do_extend_cmdline 1
  51  #else
  52  #define do_extend_cmdline 0
  53  #endif
  54 @@ -67,6 +69,80 @@ static uint32_t get_cell_size(const void
  55         return cell_size;
  56  }
  57
  58 +#if defined(CONFIG_ARM_ATAG_DTB_COMPAT_CMDLINE_MANGLE)
  59 +/**
  60 + * taken from arch/x86/boot/string.c
  61 + * local_strstr - Find the first substring in a %NUL terminated string
  62 + * @s1: The string to be searched
  63 + * @s2: The string to search for
  64 + */
  65 +static char *local_strstr(const char *s1, const char *s2)
  66 +{
  67 +       size_t l1, l2;
  68 +
  69 +       l2 = strlen(s2);
  70 +       if (!l2)
  71 +               return (char *)s1;
  72 +       l1 = strlen(s1);
  73 +       while (l1 >= l2) {
  74 +               l1--;
  75 +               if (!memcmp(s1, s2, l2))
  76 +                       return (char *)s1;
  77 +               s1++;
  78 +       }
  79 +       return NULL;
  80 +}
  81 +
  82 +static char *append_rootblock(char *dest, const char *str, int len, void *fdt)
  83 +{
  84 +       char *ptr, *end, *tmp;
  85 +       char *root="root=";
  86 +       char *find_rootblock;
  87 +       int i, l;
  88 +       const char *rootblock;
  89 +
  90 +       find_rootblock = getprop(fdt, "/chosen", "find-rootblock", &l);
  91 +       if(!find_rootblock)
  92 +               find_rootblock = root;
  93 +
  94 +       //ARM doesn't have __HAVE_ARCH_STRSTR, so it was copied from x86
  95 +       ptr = local_strstr(str, find_rootblock);
  96 +
  97 +       if(!ptr)
  98 +               return dest;
  99 +
 100 +       end = strchr(ptr, ' ');
 101 +       end = end ? (end - 1) : (strchr(ptr, 0) - 1);
 102 +
 103 +       // Some boards ubi.mtd=XX,ZZZZ, so let's check for '," too.
 104 +       tmp = strchr(ptr, ',');
 105 +
 106 +       if(tmp)
 107 +               end = end < tmp ? end : tmp - 1;
 108 +
 109 +       //find partition number (assumes format root=/dev/mtdXX | /dev/mtdblockXX | yy:XX | ubi.mtd=XX,ZZZZ )
 110 +       for( i = 0; end >= ptr && *end >= '0' && *end <= '9'; end--, i++);
 111 +       ptr = end + 1;
 112 +
 113 +       /* if append-rootblock property is set use it to append to command line */
 114 +       rootblock = getprop(fdt, "/chosen", "append-rootblock", &l);
 115 +       if(rootblock != NULL) {
 116 +               if(*dest != ' ') {
 117 +                       *dest = ' ';
 118 +                       dest++;
 119 +                       len++;
 120 +               }
 121 +               if (len + l + i <= COMMAND_LINE_SIZE) {
 122 +                       memcpy(dest, rootblock, l);
 123 +                       dest += l - 1;
 124 +                       memcpy(dest, ptr, i);
 125 +                       dest += i;
 126 +               }
 127 +       }
 128 +       return dest;
 129 +}
 130 +#endif
 131 +
 132  static void merge_fdt_bootargs(void *fdt, const char *fdt_cmdline)
 133  {
 134         char cmdline[COMMAND_LINE_SIZE];
 135 @@ -86,12 +162,21 @@ static void merge_fdt_bootargs(void *fdt
 136
 137         /* and append the ATAG_CMDLINE */
 138         if (fdt_cmdline) {
 139 +
 140 +#if defined(CONFIG_ARM_ATAG_DTB_COMPAT_CMDLINE_MANGLE)
 141 +               //save original bootloader args
 142 +               //and append ubi.mtd with root partition number to current cmdline
 143 +               setprop_string(fdt, "/chosen", "bootloader-args", fdt_cmdline);
 144 +               ptr = append_rootblock(ptr, fdt_cmdline, len, fdt);
 145 +
 146 +#else
 147                 len = strlen(fdt_cmdline);
 148                 if (ptr - cmdline + len + 2 < COMMAND_LINE_SIZE) {
 149                         *ptr++ = ' ';
 150                         memcpy(ptr, fdt_cmdline, len);
 151                         ptr += len;
 152                 }
 153 +#endif
 154         }
 155         *ptr = '\0';
 156
 157 @@ -166,7 +251,9 @@ int atags_to_fdt(void *atag_list, void *
 158                         else
 159                                 setprop_string(fdt, "/chosen", "bootargs",
 160                                                atag->u.cmdline.cmdline);
 161 -               } else if (atag->hdr.tag == ATAG_MEM) {
 162 +               }
 163 +#ifndef CONFIG_ARM_ATAG_DTB_COMPAT_CMDLINE_MANGLE
 164 +               else if (atag->hdr.tag == ATAG_MEM) {
 165                         if (memcount >= sizeof(mem_reg_property)/4)
 166                                 continue;
 167                         if (!atag->u.mem.size)
 168 @@ -210,6 +297,10 @@ int atags_to_fdt(void *atag_list, void *
 169                 setprop(fdt, "/memory", "reg", mem_reg_property,
 170                         4 * memcount * memsize);
 171         }
 172 +#else
 173 +
 174 +       }
 175 +#endif
 176
 177         return fdt_pack(fdt);
 178  }
 179 --- a/init/main.c
 180 +++ b/init/main.c
 181 @@ -103,6 +103,10 @@
 182  #define CREATE_TRACE_POINTS
 183  #include <trace/events/initcall.h>
 184
 185 +#if defined(CONFIG_ARM_ATAG_DTB_COMPAT_CMDLINE_MANGLE)
 186 +#include <linux/of.h>
 187 +#endif
 188 +
 189  static int kernel_init(void *);
 190
 191  extern void init_IRQ(void);
 192 @@ -632,6 +636,18 @@ asmlinkage __visible void __init start_k
 193         pr_notice("Kernel command line: %s\n", boot_command_line);
 194         /* parameters may set static keys */
 195         jump_label_init();
 196 +
 197 +#if defined(CONFIG_ARM_ATAG_DTB_COMPAT_CMDLINE_MANGLE)
 198 +       //Show bootloader's original command line for reference
 199 +       if(of_chosen) {
 200 +               const char *prop = of_get_property(of_chosen, "bootloader-args", NULL);
 201 +               if(prop)
 202 +                       pr_notice("Bootloader command line (ignored): %s\n", prop);
 203 +               else
 204 +                       pr_notice("Bootloader command line not present\n");
 205 +       }
 206 +#endif
 207 +
 208         parse_early_param();
 209         after_dashes = parse_args("Booting kernel",
 210                                   static_command_line, __start___param,