target/linux/ipq806x/patches-4.14/0067-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 @@ -1939,6 +1939,17 @@ 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 +69,59 @@ 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 +static char *append_rootblock(char *dest, const char *str, int len, void *fdt)
  61 +{
  62 +       char *ptr, *end;
  63 +       char *root="root=";
  64 +       int i, l;
  65 +       const char *rootblock;
  66 +
  67 +       //ARM doesn't have __HAVE_ARCH_STRSTR, so search manually
  68 +       ptr = str - 1;
  69 +
  70 +       do {
  71 +               //first find an 'r' at the begining or after a space
  72 +               do {
  73 +                       ptr++;
  74 +                       ptr = strchr(ptr, 'r');
  75 +                       if(!ptr) return dest;
  76 +
  77 +               } while (ptr != str && *(ptr-1) != ' ');
  78 +
  79 +               //then check for the rest
  80 +               for(i = 1; i <= 4; i++)
  81 +                       if(*(ptr+i) != *(root+i)) break;
  82 +
  83 +       } while (i != 5);
  84 +
  85 +       end = strchr(ptr, ' ');
  86 +       end = end ? (end - 1) : (strchr(ptr, 0) - 1);
  87 +
  88 +       //find partition number (assumes format root=/dev/mtdXX | /dev/mtdblockXX | yy:XX )
  89 +       for( i = 0; end >= ptr && *end >= '0' && *end <= '9'; end--, i++);
  90 +       ptr = end + 1;
  91 +
  92 +       /* if append-rootblock property is set use it to append to command line */
  93 +       rootblock = getprop(fdt, "/chosen", "append-rootblock", &l);
  94 +       if(rootblock != NULL) {
  95 +               if(*dest != ' ') {
  96 +                       *dest = ' ';
  97 +                       dest++;
  98 +                       len++;
  99 +               }
 100 +               if (len + l + i <= COMMAND_LINE_SIZE) {
 101 +                       memcpy(dest, rootblock, l);
 102 +                       dest += l - 1;
 103 +                       memcpy(dest, ptr, i);
 104 +                       dest += i;
 105 +               }
 106 +       }
 107 +       return dest;
 108 +}
 109 +#endif
 110 +
 111  static void merge_fdt_bootargs(void *fdt, const char *fdt_cmdline)
 112  {
 113         char cmdline[COMMAND_LINE_SIZE];
 114 @@ -86,12 +141,21 @@ static void merge_fdt_bootargs(void *fdt
 115
 116         /* and append the ATAG_CMDLINE */
 117         if (fdt_cmdline) {
 118 +
 119 +#if defined(CONFIG_ARM_ATAG_DTB_COMPAT_CMDLINE_MANGLE)
 120 +               //save original bootloader args
 121 +               //and append ubi.mtd with root partition number to current cmdline
 122 +               setprop_string(fdt, "/chosen", "bootloader-args", fdt_cmdline);
 123 +               ptr = append_rootblock(ptr, fdt_cmdline, len, fdt);
 124 +
 125 +#else
 126                 len = strlen(fdt_cmdline);
 127                 if (ptr - cmdline + len + 2 < COMMAND_LINE_SIZE) {
 128                         *ptr++ = ' ';
 129                         memcpy(ptr, fdt_cmdline, len);
 130                         ptr += len;
 131                 }
 132 +#endif
 133         }
 134         *ptr = '\0';
 135
 136 @@ -148,7 +212,9 @@ int atags_to_fdt(void *atag_list, void *
 137                         else
 138                                 setprop_string(fdt, "/chosen", "bootargs",
 139                                                atag->u.cmdline.cmdline);
 140 -               } else if (atag->hdr.tag == ATAG_MEM) {
 141 +               }
 142 +#ifndef CONFIG_ARM_ATAG_DTB_COMPAT_CMDLINE_MANGLE
 143 +               else if (atag->hdr.tag == ATAG_MEM) {
 144                         if (memcount >= sizeof(mem_reg_property)/4)
 145                                 continue;
 146                         if (!atag->u.mem.size)
 147 @@ -187,6 +253,10 @@ int atags_to_fdt(void *atag_list, void *
 148                 setprop(fdt, "/memory", "reg", mem_reg_property,
 149                         4 * memcount * memsize);
 150         }
 151 +#else
 152 +
 153 +       }
 154 +#endif
 155
 156         return fdt_pack(fdt);
 157  }
 158 --- a/init/main.c
 159 +++ b/init/main.c
 160 @@ -95,6 +95,10 @@
 161  #include <asm/sections.h>
 162  #include <asm/cacheflush.h>
 163
 164 +#if defined(CONFIG_ARM_ATAG_DTB_COMPAT_CMDLINE_MANGLE)
 165 +#include <linux/of.h>
 166 +#endif
 167 +
 168  static int kernel_init(void *);
 169
 170  extern void init_IRQ(void);
 171 @@ -574,6 +578,18 @@ asmlinkage __visible void __init start_k
 172         page_alloc_init();
 173
 174         pr_notice("Kernel command line: %s\n", boot_command_line);
 175 +
 176 +#if defined(CONFIG_ARM_ATAG_DTB_COMPAT_CMDLINE_MANGLE)
 177 +       //Show bootloader's original command line for reference
 178 +       if(of_chosen) {
 179 +               const char *prop = of_get_property(of_chosen, "bootloader-args", NULL);
 180 +               if(prop)
 181 +                       pr_notice("Bootloader command line (ignored): %s\n", prop);
 182 +               else
 183 +                       pr_notice("Bootloader command line not present\n");
 184 +       }
 185 +#endif
 186 +
 187         parse_early_param();
 188         after_dashes = parse_args("Booting kernel",
 189                                   static_command_line, __start___param,