target/linux/mvebu/patches-4.14/006-mvebu-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 This patch has been modified to be mvebu specific. The original patch
  19 did not pass the bootloader cmdline on if no append-rootblock stanza
  20 was found, resulting in blank cmdline and failure to boot.
  21
  22 Signed-off-by: Michael Gray <michael.gray@lantisproject.com>
  23 ---
  24  arch/arm/Kconfig                        | 11 +++++
  25  arch/arm/boot/compressed/atags_to_fdt.c | 72 ++++++++++++++++++++++++++++++++-
  26  init/main.c                             | 16 ++++++++
  27  3 files changed, 98 insertions(+), 1 deletion(-)
  28
  29 --- a/arch/arm/Kconfig
  30 +++ b/arch/arm/Kconfig
  31 @@ -1939,6 +1939,17 @@ config ARM_ATAG_DTB_COMPAT_CMDLINE_EXTEN
  32           The command-line arguments provided by the boot loader will be
  33           appended to the the device tree bootargs property.
  34
  35 +config ARM_ATAG_DTB_COMPAT_CMDLINE_MANGLE
  36 +       bool "Append rootblock parsing bootloader's kernel arguments"
  37 +       help
  38 +         The command-line arguments provided by the boot loader will be
  39 +         appended to a new device tree property: bootloader-args.
  40 +         If there is a property "append-rootblock" in DT under /chosen
  41 +         and a root= option in bootloaders command line it will be parsed
  42 +         and added to DT bootargs with the form: <append-rootblock>XX.
  43 +         Only command line ATAG will be processed, the rest of the ATAGs
  44 +         sent by bootloader will be ignored.
  45 +
  46  endchoice
  47
  48  config CMDLINE
  49 --- a/arch/arm/boot/compressed/atags_to_fdt.c
  50 +++ b/arch/arm/boot/compressed/atags_to_fdt.c
  51 @@ -4,6 +4,8 @@
  52
  53  #if defined(CONFIG_ARM_ATAG_DTB_COMPAT_CMDLINE_EXTEND)
  54  #define do_extend_cmdline 1
  55 +#elif defined(CONFIG_ARM_ATAG_DTB_COMPAT_CMDLINE_MANGLE)
  56 +#define do_extend_cmdline 1
  57  #else
  58  #define do_extend_cmdline 0
  59  #endif
  60 @@ -67,6 +69,65 @@ static uint32_t get_cell_size(const void
  61         return cell_size;
  62  }
  63
  64 +#if defined(CONFIG_ARM_ATAG_DTB_COMPAT_CMDLINE_MANGLE)
  65 +
  66 +static char *append_rootblock(char *dest, const char *str, int len, void *fdt)
  67 +{
  68 +       char *ptr, *end;
  69 +       char *root="root=";
  70 +       int i, l;
  71 +       const char *rootblock;
  72 +
  73 +       //ARM doesn't have __HAVE_ARCH_STRSTR, so search manually
  74 +       ptr = str - 1;
  75 +
  76 +       do {
  77 +               //first find an 'r' at the begining or after a space
  78 +               do {
  79 +                       ptr++;
  80 +                       ptr = strchr(ptr, 'r');
  81 +                       if(!ptr) return dest;
  82 +
  83 +               } while (ptr != str && *(ptr-1) != ' ');
  84 +
  85 +               //then check for the rest
  86 +               for(i = 1; i <= 4; i++)
  87 +                       if(*(ptr+i) != *(root+i)) break;
  88 +
  89 +       } while (i != 5);
  90 +
  91 +       end = strchr(ptr, ' ');
  92 +       end = end ? (end - 1) : (strchr(ptr, 0) - 1);
  93 +
  94 +       //find partition number (assumes format root=/dev/mtdXX | /dev/mtdblockXX | yy:XX )
  95 +       for( i = 0; end >= ptr && *end >= '0' && *end <= '9'; end--, i++);
  96 +       ptr = end + 1;
  97 +
  98 +       /* if append-rootblock property is set use it to append to command line */
  99 +       rootblock = getprop(fdt, "/chosen", "append-rootblock", &l);
 100 +       if(rootblock != NULL) {
 101 +               if(*dest != ' ') {
 102 +                       *dest = ' ';
 103 +                       dest++;
 104 +                       len++;
 105 +               }
 106 +               if (len + l + i <= COMMAND_LINE_SIZE) {
 107 +                       memcpy(dest, rootblock, l);
 108 +                       dest += l - 1;
 109 +                       memcpy(dest, ptr, i);
 110 +                       dest += i;
 111 +               }
 112 +       } else {
 113 +               len = strlen(str);
 114 +               if (len + 1 < COMMAND_LINE_SIZE) {
 115 +                       memcpy(dest, str, len);
 116 +                       dest += len;
 117 +               }
 118 +       }
 119 +       return dest;
 120 +}
 121 +#endif
 122 +
 123  static void merge_fdt_bootargs(void *fdt, const char *fdt_cmdline)
 124  {
 125         char cmdline[COMMAND_LINE_SIZE];
 126 @@ -86,12 +147,21 @@ static void merge_fdt_bootargs(void *fdt
 127
 128         /* and append the ATAG_CMDLINE */
 129         if (fdt_cmdline) {
 130 +
 131 +#if defined(CONFIG_ARM_ATAG_DTB_COMPAT_CMDLINE_MANGLE)
 132 +               //save original bootloader args
 133 +               //and append ubi.mtd with root partition number to current cmdline
 134 +               setprop_string(fdt, "/chosen", "bootloader-args", fdt_cmdline);
 135 +               ptr = append_rootblock(ptr, fdt_cmdline, len, fdt);
 136 +
 137 +#else
 138                 len = strlen(fdt_cmdline);
 139                 if (ptr - cmdline + len + 2 < COMMAND_LINE_SIZE) {
 140                         *ptr++ = ' ';
 141                         memcpy(ptr, fdt_cmdline, len);
 142                         ptr += len;
 143                 }
 144 +#endif
 145         }
 146         *ptr = '\0';
 147
 148 @@ -148,7 +218,9 @@ int atags_to_fdt(void *atag_list, void *
 149                         else
 150                                 setprop_string(fdt, "/chosen", "bootargs",
 151                                                atag->u.cmdline.cmdline);
 152 -               } else if (atag->hdr.tag == ATAG_MEM) {
 153 +               }
 154 +#ifndef CONFIG_ARM_ATAG_DTB_COMPAT_CMDLINE_MANGLE
 155 +               else if (atag->hdr.tag == ATAG_MEM) {
 156                         if (memcount >= sizeof(mem_reg_property)/4)
 157                                 continue;
 158                         if (!atag->u.mem.size)
 159 @@ -187,6 +259,10 @@ int atags_to_fdt(void *atag_list, void *
 160                 setprop(fdt, "/memory", "reg", mem_reg_property,
 161                         4 * memcount * memsize);
 162         }
 163 +#else
 164 +
 165 +       }
 166 +#endif
 167
 168         return fdt_pack(fdt);
 169  }
 170 --- a/init/main.c
 171 +++ b/init/main.c
 172 @@ -95,6 +95,10 @@
 173  #include <asm/sections.h>
 174  #include <asm/cacheflush.h>
 175
 176 +#if defined(CONFIG_ARM_ATAG_DTB_COMPAT_CMDLINE_MANGLE)
 177 +#include <linux/of.h>
 178 +#endif
 179 +
 180  static int kernel_init(void *);
 181
 182  extern void init_IRQ(void);
 183 @@ -574,6 +578,18 @@ asmlinkage __visible void __init start_k
 184         page_alloc_init();
 185
 186         pr_notice("Kernel command line: %s\n", boot_command_line);
 187 +
 188 +#if defined(CONFIG_ARM_ATAG_DTB_COMPAT_CMDLINE_MANGLE)
 189 +       //Show bootloader's original command line for reference
 190 +       if(of_chosen) {
 191 +               const char *prop = of_get_property(of_chosen, "bootloader-args", NULL);
 192 +               if(prop)
 193 +                       pr_notice("Bootloader command line (ignored): %s\n", prop);
 194 +               else
 195 +                       pr_notice("Bootloader command line not present\n");
 196 +       }
 197 +#endif
 198 +
 199         parse_early_param();
 200         after_dashes = parse_args("Booting kernel",
 201                                   static_command_line, __start___param,