0004-Obey-2.06-boot-protocol-s-cmdline_size.patch

From cbb7e3d28164467b104814484965d30333d529ba Mon Sep 17 00:00:00 2001
From: Lubomir Rintel <lkundrak@v3.sk>
Date: Sun, 11 Jan 2009 12:04:10 +0100
Subject: [PATCH] Obey 2.06 boot protocol's cmdline_size

This increases the limit for the command line according to kernel's
setting, up to 0x7FF characters. This limit was chosen because it
matches current kernel's limitation and doesn't need substantial
change in memory layout, consuming only spare space (and leaving
once as much bytes spare for possible future expansion).

Bug Report: https://bugzilla.redhat.com/attachment.cgi?id=327541
---
 stage2/boot.c   |   13 +++++++++++--
 stage2/shared.h |    7 +++++--
 2 files changed, 16 insertions(+), 4 deletions(-)

diff --git a/stage2/boot.c b/stage2/boot.c
index eee8bb1..2267721 100644
--- a/stage2/boot.c
+++ b/stage2/boot.c
@@ -228,6 +228,7 @@ load_image (char *kernel, char *arg, kernel_t suggested_type,
     {
       int big_linux = 0;
       int setup_sects = lh->setup_sects;
+      int cmdline_size = 0xff;
 
       if (lh->header == LINUX_MAGIC_SIGNATURE && lh->version >= 0x0200)
 	{
@@ -255,6 +256,14 @@ load_image (char *kernel, char *arg, kernel_t suggested_type,
 	      lh->cl_offset = LINUX_CL_OFFSET;
 	      lh->setup_move_size = LINUX_SETUP_MOVE_SIZE;
 	    }
+
+	  if (lh->version >= 0x0206)
+	    {
+	      cmdline_size = lh->cmdline_size;
+	      if (cmdline_size > (LINUX_CL_END_OFFSET - LINUX_CL_OFFSET))
+		cmdline_size = LINUX_CL_END_OFFSET - LINUX_CL_OFFSET;
+	    }
+
 	}
       else
 	{
@@ -411,7 +420,7 @@ load_image (char *kernel, char *arg, kernel_t suggested_type,
 	    char *src = skip_to (0, arg);
 	    char *dest = linux_data_tmp_addr + LINUX_CL_OFFSET;
 	
-	    while (dest < linux_data_tmp_addr + LINUX_CL_END_OFFSET && *src)
+	    while (dest < linux_data_tmp_addr + LINUX_CL_OFFSET + cmdline_size && *src)
 	      *(dest++) = *(src++);
 	
 	    /* Old Linux kernels have problems determining the amount of
@@ -432,7 +441,7 @@ load_image (char *kernel, char *arg, kernel_t suggested_type,
 	    if (! grub_strstr (arg, "mem=")
 		&& ! (load_flags & KERNEL_LOAD_NO_MEM_OPTION)
 		&& lh->version < 0x0203		/* kernel version < 2.4.18 */
-		&& dest + 15 < linux_data_tmp_addr + LINUX_CL_END_OFFSET)
+		&& dest + 15 < linux_data_tmp_addr + LINUX_CL_OFFSET + cmdline_size)
 	      {
 		*dest++ = ' ';
 		*dest++ = 'm';
diff --git a/stage2/shared.h b/stage2/shared.h
index 93f586f..49711af 100644
--- a/stage2/shared.h
+++ b/stage2/shared.h
@@ -162,8 +162,8 @@ extern void *grub_scratch_mem;
 #define LINUX_VID_MODE_ASK		0xFFFD
 
 #define LINUX_CL_OFFSET			0x9000
-#define LINUX_CL_END_OFFSET		0x90FF
-#define LINUX_SETUP_MOVE_SIZE		0x9100
+#define LINUX_CL_END_OFFSET		0x97FF
+#define LINUX_SETUP_MOVE_SIZE		0x9800
 #define LINUX_CL_MAGIC			0xA33F
 
 /*
@@ -423,6 +423,9 @@ struct linux_kernel_header
   unsigned short pad1;			/* Unused */
   char *cmd_line_ptr;			/* Points to the kernel command line */
   unsigned int initrd_addr_max;		/* The highest address of initrd */
+  unsigned int kernel_alignment;	/* Physical addr alignment required for kernel */
+  unsigned int relocatable_kernel;	/* Whether kernel is relocatable or not */
+  unsigned int cmdline_size;		/* Maximum size of the kernel command line */
 } __attribute__ ((packed));
 
 /* Memory map address range descriptor used by GET_MMAP_ENTRY. */
-- 
1.5.5.6