target/linux/mvebu/patches-5.15/300-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 | 85 ++++++++++++++++++++++++-
  26  init/main.c                             | 16 +++++
  27  3 files changed, 111 insertions(+), 1 deletion(-)
  28
  29 --- a/arch/arm/Kconfig
  30 +++ b/arch/arm/Kconfig
  31 @@ -1727,6 +1727,17 @@ 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 @@ -5,6 +5,8 @@
  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 @@ -69,6 +71,72 @@ 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)
  82 +                               goto no_append;
  83 +
  84 +               } while (ptr != str && *(ptr-1) != ' ');
  85 +
  86 +               //then check for the rest
  87 +               for(i = 1; i <= 4; i++)
  88 +                       if(*(ptr+i) != *(root+i)) break;
  89 +
  90 +       } while (i != 5);
  91 +
  92 +       end = strchr(ptr, ' ');
  93 +       end = end ? (end - 1) : (strchr(ptr, 0) - 1);
  94 +
  95 +       //find partition number (assumes format root=/dev/mtdXX | /dev/mtdblockXX | yy:XX )
  96 +       for( i = 0; end >= ptr && *end >= '0' && *end <= '9'; end--, i++);
  97 +       ptr = end + 1;
  98 +
  99 +       /* if append-rootblock property is set use it to append to command line */
 100 +       rootblock = getprop(fdt, "/chosen", "append-rootblock", &l);
 101 +       if (rootblock == NULL)
 102 +               goto no_append;
 103 +
 104 +       if (*dest != ' ') {
 105 +               *dest = ' ';
 106 +               dest++;
 107 +               len++;
 108 +       }
 109 +
 110 +       if (len + l + i <= COMMAND_LINE_SIZE) {
 111 +               memcpy(dest, rootblock, l);
 112 +               dest += l - 1;
 113 +               memcpy(dest, ptr, i);
 114 +               dest += i;
 115 +       }
 116 +
 117 +       return dest;
 118 +
 119 +no_append:
 120 +       len = strlen(str);
 121 +       if (len + 1 < COMMAND_LINE_SIZE) {
 122 +               memcpy(dest, str, len);
 123 +               dest += len;
 124 +       }
 125 +
 126 +       return dest;
 127 +}
 128 +#endif
 129 +
 130  static void merge_fdt_bootargs(void *fdt, const char *fdt_cmdline)
 131  {
 132         char cmdline[COMMAND_LINE_SIZE];
 133 @@ -88,12 +156,21 @@ static void merge_fdt_bootargs(void *fdt
 134
 135         /* and append the ATAG_CMDLINE */
 136         if (fdt_cmdline) {
 137 +
 138 +#if defined(CONFIG_ARM_ATAG_DTB_COMPAT_CMDLINE_MANGLE)
 139 +               //save original bootloader args
 140 +               //and append ubi.mtd with root partition number to current cmdline
 141 +               setprop_string(fdt, "/chosen", "bootloader-args", fdt_cmdline);
 142 +               ptr = append_rootblock(ptr, fdt_cmdline, len, fdt);
 143 +
 144 +#else
 145                 len = strlen(fdt_cmdline);
 146                 if (ptr - cmdline + len + 2 < COMMAND_LINE_SIZE) {
 147                         *ptr++ = ' ';
 148                         memcpy(ptr, fdt_cmdline, len);
 149                         ptr += len;
 150                 }
 151 +#endif
 152         }
 153         *ptr = '\0';
 154
 155 @@ -168,7 +245,9 @@ int atags_to_fdt(void *atag_list, void *
 156                         else
 157                                 setprop_string(fdt, "/chosen", "bootargs",
 158                                                atag->u.cmdline.cmdline);
 159 -               } else if (atag->hdr.tag == ATAG_MEM) {
 160 +               }
 161 +#ifndef CONFIG_ARM_ATAG_DTB_COMPAT_CMDLINE_MANGLE
 162 +               else if (atag->hdr.tag == ATAG_MEM) {
 163                         if (memcount >= sizeof(mem_reg_property)/4)
 164                                 continue;
 165                         if (!atag->u.mem.size)
 166 @@ -212,6 +291,10 @@ int atags_to_fdt(void *atag_list, void *
 167                 setprop(fdt, "/memory", "reg", mem_reg_property,
 168                         4 * memcount * memsize);
 169         }
 170 +#else
 171 +
 172 +       }
 173 +#endif
 174
 175         return fdt_pack(fdt);
 176  }
 177 --- a/init/main.c
 178 +++ b/init/main.c
 179 @@ -114,6 +114,10 @@
 180
 181  #include <kunit/test.h>
 182
 183 +#if defined(CONFIG_ARM_ATAG_DTB_COMPAT_CMDLINE_MANGLE)
 184 +#include <linux/of.h>
 185 +#endif
 186 +
 187  static int kernel_init(void *);
 188
 189  extern void init_IRQ(void);
 190 @@ -991,6 +995,18 @@ asmlinkage __visible void __init __no_sa
 191         page_alloc_init();
 192
 193         pr_notice("Kernel command line: %s\n", saved_command_line);
 194 +
 195 +#if defined(CONFIG_ARM_ATAG_DTB_COMPAT_CMDLINE_MANGLE)
 196 +       //Show bootloader's original command line for reference
 197 +       if(of_chosen) {
 198 +               const char *prop = of_get_property(of_chosen, "bootloader-args", NULL);
 199 +               if(prop)
 200 +                       pr_notice("Bootloader command line (ignored): %s\n", prop);
 201 +               else
 202 +                       pr_notice("Bootloader command line not present\n");
 203 +       }
 204 +#endif
 205 +
 206         /* parameters may set static keys */
 207         jump_label_init();
 208         parse_early_param();