[patch 2/2] x86: lds - Use THREAD_SIZE instead of numeric constant

[Cyrill Gorcunov <gorcunov@gmail.com>]

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Though we use PDA for regular task stack but that
is not acceptable for init_task wich is special
one. We still have to allocate init_task's stack
in that manner.

Signed-off-by: Cyrill Gorcunov <gorcunov@gmail.com>
---

Ingo, Peter, I can be wrong but take a look please
to x86/lgest/i386_head.S:41

	/* Set up the initial stack so we can run C code. */
	movl $(init_thread_union+THREAD_SIZE),%esp

if we just eliminate this string from lds scripts - I bet
we get bad situation here. Xen has a similar trick.
And even head_32.S and head_64.S both have

32bits
======
ENTRY(stack_start)
	.long init_thread_union+THREAD_SIZE

64bits
======
	ENTRY(init_rsp)
	.quad  init_thread_union+THREAD_SIZE-8

So if we just remove that string from lds file - we will
be screwed up I think ;)

Index: linux-2.6.git/arch/x86/kernel/vmlinux_64.lds.S
===================================================================
--- linux-2.6.git.orig/arch/x86/kernel/vmlinux_64.lds.S	2008-02-17 13:56:54.000000000 +0300
+++ linux-2.6.git/arch/x86/kernel/vmlinux_64.lds.S	2008-02-17 14:10:21.000000000 +0300
@@ -129,7 +129,7 @@ SECTIONS
 #undef VVIRT_OFFSET
 #undef VVIRT
 
-  . = ALIGN(8192);		/* init_task */
+  . = ALIGN(THREAD_SIZE);	/* init_task */
   .data.init_task : AT(ADDR(.data.init_task) - LOAD_OFFSET) {
 	*(.data.init_task)
   }:data.init

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