ARM: add TEXT_OFFSET to decompressor kexec image structure

Add the TEXT_OFFSET to the decompressor's kexec image structure to
kexec knows what offset to use.
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>

arch/arm/Makefile

@@ -139,6 +139,9 @@ head-y		:= arch/arm/kernel/head$(MMUEXT).o
 
 # Text offset. This list is sorted numerically by address in order to
 # provide a means to avoid/resolve conflicts in multi-arch kernels.
+# Note: the 32kB below this value is reserved for use by the kernel
+# during boot, and this offset is critical to the functioning of
+# kexec-tools.
 textofs-y	:= 0x00008000
 # We don't want the htc bootloader to corrupt kernel during resume
 textofs-$(CONFIG_PM_H1940)      := 0x00108000

arch/arm/boot/compressed/Makefile

@@ -70,6 +70,7 @@ ZBSSADDR	:= ALIGN(8)
 endif
 
 CPPFLAGS_vmlinux.lds := -DTEXT_START="$(ZTEXTADDR)" -DBSS_START="$(ZBSSADDR)"
+CPPFLAGS_vmlinux.lds += -DTEXT_OFFSET="$(TEXT_OFFSET)"
 
 compress-$(CONFIG_KERNEL_GZIP) = gzip
 compress-$(CONFIG_KERNEL_LZO)  = lzo

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

@@ -42,10 +42,11 @@ SECTIONS
   }
   .table : ALIGN(4) {
     _table_start = .;
-    LONG(ZIMAGE_MAGIC(4))
+    LONG(ZIMAGE_MAGIC(5))
     LONG(ZIMAGE_MAGIC(0x5a534c4b))
     LONG(ZIMAGE_MAGIC(__piggy_size_addr - _start))
     LONG(ZIMAGE_MAGIC(_kernel_bss_size))
+    LONG(ZIMAGE_MAGIC(TEXT_OFFSET))
     LONG(0)
     _table_end = .;
   }