FreeDOS direct loading support.

* docs/grub.texi (Supported OS): Add FreeDOS.
	* grub-core/Makefile.core.def (freedos): New module.
	* grub-core/lib/i386/relocator.c (grub_relocator16_ebx): New extern
	variable.
	(grub_relocator16_boot): Handle %ebx.
	* grub-core/lib/i386/relocator16.S: Likewise.
	* grub-core/loader/i386/pc/freedos.c: New file.

ChangeLog

@@ -1,3 +1,15 @@
+2011-05-18  Vladimir Serbinenko  <phcoder@gmail.com>
+
+	FreeDOS direct loading support.
+
+	* docs/grub.texi (Supported OS): Add FreeDOS.
+	* grub-core/Makefile.core.def (freedos): New module.
+	* grub-core/lib/i386/relocator.c (grub_relocator16_ebx): New extern
+	variable.
+	(grub_relocator16_boot): Handle %ebx.
+	* grub-core/lib/i386/relocator16.S: Likewise.
+	* grub-core/loader/i386/pc/freedos.c: New file.
+
 2011-05-18  Vladimir Serbinenko  <phcoder@gmail.com>
 
 	Long Linux command line support.

docs/grub.texi

@@ -3942,6 +3942,7 @@ X86 support is summarised in the following table. ``Yes'' means that the kernel
 @item                                @tab BIOS    @tab Coreboot
 @item BIOS chainloading              @tab yes     @tab no (1)
 @item NTLDR                          @tab yes     @tab no (1)
+@item Freedos                        @tab yes     @tab no (1)
 @item FreeBSD bootloader             @tab yes     @tab crashes (1)
 @item 32-bit kFreeBSD                @tab yes     @tab crashes (2,6)
 @item 64-bit kFreeBSD                @tab yes     @tab crashes (2,6)
@@ -3966,6 +3967,7 @@ X86 support is summarised in the following table. ``Yes'' means that the kernel
 @item                                @tab Multiboot    @tab Qemu 
 @item BIOS chainloading              @tab no (1)       @tab no (1)
 @item NTLDR                          @tab no (1)       @tab no (1)
+@item FreeDOS                        @tab no (1)       @tab no (1)
 @item FreeBSD bootloader             @tab crashes (1)  @tab crashes (1)
 @item 32-bit kFreeBSD                @tab crashes (6)  @tab crashes (6)
 @item 64-bit kFreeBSD                @tab crashes (6)  @tab crashes (6)
@@ -3990,6 +3992,7 @@ X86 support is summarised in the following table. ``Yes'' means that the kernel
 @item                                @tab 32-bit EFI    @tab 64-bit EFI
 @item BIOS chainloading              @tab no (1)        @tab no (1)
 @item NTLDR                          @tab no (1)        @tab no (1)
+@item FreeDOS                        @tab no (1)        @tab no (1)
 @item FreeBSD bootloader             @tab crashes (1)   @tab crashes (1)
 @item 32-bit kFreeBSD                @tab headless      @tab headless
 @item 64-bit kFreeBSD                @tab headless      @tab headless
@@ -4014,6 +4017,7 @@ X86 support is summarised in the following table. ``Yes'' means that the kernel
 @item                                @tab IEEE1275
 @item BIOS chainloading              @tab no (1)
 @item NTLDR                          @tab no (1)
+@item FreeDOS                        @tab no (1)
 @item FreeBSD bootloader             @tab crashes (1)
 @item 32-bit kFreeBSD                @tab crashes (6)
 @item 64-bit kFreeBSD                @tab crashes (6)

grub-core/Makefile.core.def

@@ -1230,6 +1230,12 @@ module = {
   enable = i386_pc;
 };
 
+module = {
+  name = freedos;
+  i386_pc = loader/i386/pc/freedos.c;
+  enable = i386_pc;
+};
+
 module = {
   name = multiboot2;
   cppflags = "-DGRUB_USE_MULTIBOOT2";

grub-core/lib/i386/relocator.c

@@ -50,6 +50,7 @@ extern grub_uint16_t grub_relocator16_gs;
 extern grub_uint16_t grub_relocator16_ss;
 extern grub_uint16_t grub_relocator16_sp;
 extern grub_uint32_t grub_relocator16_edx;
+extern grub_uint32_t grub_relocator16_ebx;
 
 extern grub_uint8_t grub_relocator32_start;
 extern grub_uint8_t grub_relocator32_end;
@@ -212,6 +213,7 @@ grub_relocator16_boot (struct grub_relocator *rel,
   grub_relocator16_ss = state.ss;
   grub_relocator16_sp = state.sp;
 
+  grub_relocator16_ebx = state.ebx;
   grub_relocator16_edx = state.edx;
 
   grub_memmove (get_virtual_current_address (ch), &grub_relocator16_start,

grub-core/lib/i386/relocator16.S

@@ -137,6 +137,11 @@ VARIABLE(grub_relocator16_sp)
 VARIABLE(grub_relocator16_edx)
 	.long	0
 
+	/* movw imm32, %ebx.  */
+	.byte	0x66, 0xbb
+VARIABLE(grub_relocator16_ebx)
+	.long	0
+
 	/* Cleared direction flag is of no problem with any current
 	   payload and makes this implementation easier.  */
 	cld

grub-core/loader/i386/pc/freedos.c

@@ -0,0 +1,136 @@
+/* chainloader.c - boot another boot loader */
+/*
+ *  GRUB  --  GRand Unified Bootloader
+ *  Copyright (C) 2002,2004,2007,2009,2010  Free Software Foundation, Inc.
+ *
+ *  GRUB is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  GRUB is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with GRUB.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <grub/loader.h>
+#include <grub/file.h>
+#include <grub/err.h>
+#include <grub/device.h>
+#include <grub/disk.h>
+#include <grub/misc.h>
+#include <grub/types.h>
+#include <grub/partition.h>
+#include <grub/dl.h>
+#include <grub/command.h>
+#include <grub/machine/biosnum.h>
+#include <grub/i18n.h>
+#include <grub/video.h>
+#include <grub/mm.h>
+#include <grub/cpu/relocator.h>
+
+static grub_dl_t my_mod;
+static struct grub_relocator *rel;
+static grub_uint32_t ebx = 0xffffffff;
+
+#define GRUB_FREEDOS_SEGMENT         0x60
+#define GRUB_FREEDOS_STACK_SEGMENT         0x1fe0
+#define GRUB_FREEDOS_STACK_POINTER         0x8000
+
+static grub_err_t
+grub_freedos_boot (void)
+{
+  struct grub_relocator16_state state = { 
+    .cs = GRUB_FREEDOS_SEGMENT,
+    .ip = 0,
+    .ds = 0,
+    .es = 0,
+    .fs = 0,
+    .gs = 0,
+    .ss = GRUB_FREEDOS_STACK_SEGMENT,
+    .sp = GRUB_FREEDOS_STACK_POINTER,
+    .ebx = ebx,
+    .edx = 0
+  };
+  grub_video_set_mode ("text", 0, 0);
+
+  return grub_relocator16_boot (rel, state);
+}
+
+static grub_err_t
+grub_freedos_unload (void)
+{
+  grub_relocator_unload (rel);
+  rel = NULL;
+  grub_dl_unref (my_mod);
+  return GRUB_ERR_NONE;
+}
+
+static grub_err_t
+grub_cmd_freedos (grub_command_t cmd __attribute__ ((unused)),
+		int argc, char *argv[])
+{
+  grub_file_t file = 0;
+  grub_err_t err;
+  void *kernelsys;
+  grub_size_t kernelsyssize;
+
+  if (argc == 0)
+    return grub_error (GRUB_ERR_BAD_ARGUMENT, "no file specified");
+
+  grub_dl_ref (my_mod);
+
+  rel = grub_relocator_new ();
+  if (!rel)
+    goto fail;
+
+  file = grub_file_open (argv[0]);
+  if (! file)
+    goto fail;
+
+  ebx = grub_get_root_biosnumber ();
+
+  kernelsyssize = grub_file_size (file);
+  {
+    grub_relocator_chunk_t ch;
+    err = grub_relocator_alloc_chunk_addr (rel, &ch, GRUB_FREEDOS_SEGMENT << 4,
+					   kernelsyssize);
+    if (err)
+      goto fail;
+    kernelsys = get_virtual_current_address (ch);
+  }
+
+  if (grub_file_read (file, kernelsys, kernelsyssize)
+      != (grub_ssize_t) kernelsyssize)
+    goto fail;
+ 
+  grub_loader_set (grub_freedos_boot, grub_freedos_unload, 1);
+  return GRUB_ERR_NONE;
+
+ fail:
+
+  if (file)
+    grub_file_close (file);
+
+  grub_freedos_unload ();
+
+  return grub_errno;
+}
+
+static grub_command_t cmd;
+
+GRUB_MOD_INIT(freedos)
+{
+  cmd = grub_register_command ("freedos", grub_cmd_freedos,
+			       0, N_("Load FreeDOS kernel.sys."));
+  my_mod = mod;
+}
+
+GRUB_MOD_FINI(freedos)
+{
+  grub_unregister_command (cmd);
+}

include/grub/i386/relocator.h

@@ -46,6 +46,7 @@ struct grub_relocator16_state
   grub_uint16_t ss;
   grub_uint16_t sp;
   grub_uint16_t ip;
+  grub_uint32_t ebx;
   grub_uint32_t edx;
 };