ARM: add additional table to compressed kernel

Add an additional extendable table to the compressed kernel so that we
can provide further information to boot loaders regarding the properties
of the image contained within.

This is necessary for correct behaviour of kexec.
Tested-by: NTony Lindgren <tony@atomide.com>
Tested-by: NKeerthy <j-keerthy@ti.com>
Signed-off-by: NRussell King <rmk+kernel@armlinux.org.uk>

arch/arm/boot/compressed/head.S

@@ -143,6 +143,8 @@ start:
 		.word	_magic_start	@ absolute load/run zImage address
 		.word	_magic_end	@ zImage end address
 		.word	0x04030201	@ endianness flag
+		.word	0x45454545	@ another magic number to indicate
+		.word	_magic_table	@ additional data table
 
 		__EFI_HEADER
 1:

arch/arm/boot/compressed/vmlinux.lds.S

@@ -44,12 +44,22 @@ SECTIONS
     *(.glue_7t)
     *(.glue_7)
   }
+  .table : ALIGN(4) {
+    _table_start = .;
+    LONG(ZIMAGE_MAGIC(2))
+    LONG(ZIMAGE_MAGIC(0x5a534c4b))
+    LONG(ZIMAGE_MAGIC(__piggy_size_addr - _start))
+    LONG(ZIMAGE_MAGIC(_kernel_bss_size))
+    LONG(0)
+    _table_end = .;
+  }
   .rodata : {
     *(.rodata)
     *(.rodata.*)
   }
   .piggydata : {
     *(.piggydata)
+    __piggy_size_addr = . - 4;
   }
 
   . = ALIGN(4);
@@ -88,6 +98,7 @@ SECTIONS
   _magic_sig = ZIMAGE_MAGIC(0x016f2818);
   _magic_start = ZIMAGE_MAGIC(_start);
   _magic_end = ZIMAGE_MAGIC(_edata);
+  _magic_table = ZIMAGE_MAGIC(_table_start - _start);
 
   . = BSS_START;
   __bss_start = .;