unify kernel command line handling

We now use MIPS_CMDLINE_DTB_EXTEND for all boot varieties (tftpboot, flash boot, kexec) with the addition of MIPS_BOOTLOADER_CMDLINE_REQUIRE_COOKIE - local patch - so that the bootloader args are ignored unless they contain the string "liminix"
2023-03-23 21:50:44 +00:00 · 2023-03-23 21:50:44 +00:00 · a5cfa37ed3
commit a5cfa37ed3
parent 1c36f1b373
6 changed files with 74 additions and 10 deletions
--- a/modules/base.nix
+++ b/modules/base.nix
@ -79,6 +79,10 @@ in {
        MODULE_SIG = "y";
        DEBUG_FS = "y";

+        MIPS_BOOTLOADER_CMDLINE_REQUIRE_COOKIE = "y";
+        MIPS_BOOTLOADER_CMDLINE_COOKIE = "\"liminix\"";
+        MIPS_CMDLINE_DTB_EXTEND = "y";
+
        # basic networking protocols
        NET = "y";
        UNIX = "y";
--- a/modules/flashable.nix
+++ b/modules/flashable.nix
@ -14,10 +14,6 @@ in {
    kernel = {
      config = {
        MTD_SPLIT_UIMAGE_FW = "y";
-        # ignore the commandline provided by U-Boot because it's most
-        # likely wrong
-        MIPS_CMDLINE_FROM_BOOTLOADER = lib.mkForce "n";
-        MIPS_CMDLINE_FROM_DTB = "y";
      };
    };

--- a/modules/kexecboot.nix
+++ b/modules/kexecboot.nix
@ -11,9 +11,6 @@ in {
  config = {
    boot.ramdisk.enable = true;

-    kernel.config.MIPS_CMDLINE_FROM_DTB = "y";
-    kernel.config.MIPS_CMDLINE_FROM_BOOTLOADER = mkForce "n";
-
    outputs.kexecboot =
      let o = config.outputs; in
      pkgs.runCommand "kexecboot" {} ''
--- a/modules/tftpboot.nix
+++ b/modules/tftpboot.nix
@ -11,7 +11,6 @@ in {
  imports = [ ./ramdisk.nix ];
  config = {
    boot.ramdisk.enable = true;
-    kernel.config.MIPS_CMDLINE_FROM_BOOTLOADER = "y";

    outputs.tftpboot =
      let o = config.outputs; in
@ -35,12 +34,12 @@ in {
          squashfsStart=0x$(printf %x $((${cfg.loadAddress} + 0x100000 + $uimageSize)))
          squashfsBytes=$(($(stat -L -c %s ${config.outputs.squashfs}) + 0x100000 &(~0xfffff)))
          squashfsMb=$(($squashfsBytes >> 20))
-          cmd="mtdparts=phram0:''${squashfsMb}M(nix) phram.phram=phram0,''${squashfsStart},''${squashfsMb}Mi memmap=''${squashfsMb}M\$''${squashfsStart} root=1f00";
+          cmd="mtdparts=phram0:''${squashfsMb}M(rootfs) phram.phram=phram0,''${squashfsStart},''${squashfsMb}Mi memmap=''${squashfsMb}M\$''${squashfsStart} root=1f00";

          cat > $out << EOF
          setenv serverip ${cfg.serverip}
          setenv ipaddr ${cfg.ipaddr}
-          setenv bootargs '${concatStringsSep " " config.boot.commandLine} $cmd'
+          setenv bootargs 'liminix $cmd'
          tftp 0x$(printf %x ${cfg.loadAddress}) result/uimage ; tftp 0x$(printf %x $squashfsStart) result/squashfs
          bootm 0x$(printf %x ${cfg.loadAddress})
          EOF
--- a/pkgs/kernel/cmdline-cookie.patch
+++ b/pkgs/kernel/cmdline-cookie.patch
@ -0,0 +1,63 @@
+diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
+index 393eb2133243..f61bfbaa4001 100644
+--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
+@@ -3157,6 +3157,24 @@ choice
+ 		  if you don't intend to always append a DTB.
+ endchoice
+ 
+config MIPS_BOOTLOADER_CMDLINE_REQUIRE_COOKIE
+	bool "Ignore bootloader command-line unless cookie present"
+	default n
+
+config MIPS_BOOTLOADER_CMDLINE_COOKIE
+	string "Bootloader kernel argument cookie string"
+	depends on MIPS_BOOTLOADER_CMDLINE_REQUIRE_COOKIE
+	help
+	  Use bootloader command line if and only if it contains
+	  this string. Some bootloaders allow setting the command line
+	  for interactive boots but provide an incorrect (and
+	  unchangeable) default when booting unattended.
+
+	  This option can be combined with e.g. MIPS_CMDLINE_DTB_EXTEND
+	  or MIPS_CMDLINE_BUILTIN_EXTEND: it doesn't affect
+	  where else your command line comes from, just whether
+	  the bootloader-provided command line is used as part of it.
+
+ choice
+ 	prompt "Kernel command line type" if !CMDLINE_OVERRIDE
+ 	default MIPS_CMDLINE_FROM_DTB if USE_OF && !ATH79 && !MACH_INGENIC && \
+diff --git a/arch/mips/kernel/setup.c b/arch/mips/kernel/setup.c
+index ef73ba1e0ec1..52a836c43630 100644
+--- a/arch/mips/kernel/setup.c
+++ b/arch/mips/kernel/setup.c
+@@ -72,6 +72,12 @@ static const char builtin_cmdline[] __initconst = CONFIG_CMDLINE;
+ static const char builtin_cmdline[] __initconst = "";
+ #endif
+ 
+#ifdef CONFIG_MIPS_BOOTLOADER_CMDLINE_REQUIRE_COOKIE
+static const char cmdline_cookie[] __initconst = CONFIG_MIPS_BOOTLOADER_CMDLINE_COOKIE;
+#else
+static const char cmdline_cookie[] __initconst = NULL;
+#endif
+
+ /*
+  * mips_io_port_base is the begin of the address space to which x86 style
+  * I/O ports are mapped.
+@@ -558,6 +564,16 @@ static void __init bootcmdline_init(void)
+ 		return;
+ 	}
+ 
+	/* If CMDLINE_REQUIRE_COOKIE is set to a string, we require that
+	 * string to be present in the bootloader command line, otherwise
+	 * we ignore it. This is to accommodate bootloaders that allow
+	 * the command line to be specified for interactive boots but
+	 * hardcode an incorrect command line for unattended boots */
+#ifdef CONFIG_MIPS_BOOTLOADER_CMDLINE_REQUIRE_COOKIE
+	if(strstr(arcs_cmdline, cmdline_cookie) == NULL) {
+	    arcs_cmdline[0] = '\0';
+	}
+#endif
+ 	/*
+ 	 * If the user specified a built-in command line &
+ 	 * MIPS_CMDLINE_BUILTIN_EXTEND, then the built-in command line is
--- a/pkgs/kernel/default.nix
+++ b/pkgs/kernel/default.nix
@ -41,6 +41,7 @@ stdenv.mkDerivation rec {
    "unpackPhase"
    "butcherPkgconfig"
    "extraPatchPhase"
+    "patchPhase"
    "patchScripts"
    "configurePhase"
    "checkConfigurationPhase"
@ -48,6 +49,10 @@ stdenv.mkDerivation rec {
    "installPhase"
  ];

+  patches = [
+    ./cmdline-cookie.patch
+  ];
+
  # this is here to work around what I think is a bug in nixpkgs
  # packaging of ncurses: it installs pkg-config data files which
  # don't produce any -L options when queried with "pkg-config --lib