question about adding a field into linux boot header

[GuoMinskey]

I want to use setup_data fields of linux boot header,  but grub doesn't

support it. So,  I cone latest grub repo (1.99) and modify grub code as

follows:

1.  in include/grub/i386/linux.h,  

 struct linux_kernel_header

 {

@@ -130,6 +144,8 @@

   grub_uint16_t pad1;         /* Unused */

   grub_uint32_t cmd_line_ptr; /* Points to the kernel command line */

   grub_uint32_t initrd_addr_max;        /* Highest address for initrd */

+  grub_uint32_t pad2[8];

+  grub_uint64_t new_field;    <--------------  aligned to the offset : 0x250 as linux

 } __attribute__ ((packed));

2.  grub-core/loader/i386/linux.c

     I add a command by following "initrd", but simply as follows:

       static grub_err_t

           grub_cmd_test(cmd, argc, argv[])

      {

                 grub_printf("entering my test command\n");

                 ...   //ensure kernel is loaded

 

                 struct linux_kernel_header *lh = (struct linux_kernel_header *) real_mode_mem;  

                 lh->new_field  = 0x34FFFFFF;

      }

 

    

 when I boot GRUB with my command,  GRUB panic in relocator. I print the kernel

header, seems the header is there ( I mean real_mode_mem).   If I removed the line

"lh->new_field = 0x34FFFFFF",  GRUB can work.  

Did I miss something if I want pass this field into linux kernel ?

thanks,

-minskey