s390: clean up stacks setup

Replace hard coded stack frame overhead values with STACK_FRAME_OVERHEAD
definition. Avoid unnecessary arithmetic instructions.

Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

arch/s390/boot/compressed/head.S

@@ -12,6 +12,7 @@
 #include <asm/asm-offsets.h>
 #include <asm/thread_info.h>
 #include <asm/page.h>
+#include <asm/ptrace.h>
 #include "sizes.h"
 
 __HEAD
@@ -20,7 +21,6 @@ ENTRY(startup_decompressor)
 .LPG1:
 	# setup stack
 	lg	%r15,.Lstack-.LPG1(%r13)
-	aghi	%r15,-160
 	brasl	%r14,decompress_kernel
 	# Set up registers for memory mover. We move the decompressed image to
 	# 0x100000, where startup_continue of the decompressed image is supposed
@@ -45,7 +45,7 @@ mover_end:
 
 	.align	8
 .Lstack:
-	.quad	0x8000 + (1<<(PAGE_SHIFT+THREAD_SIZE_ORDER))
+	.quad	0x8000 + THREAD_SIZE - STACK_FRAME_OVERHEAD
 .Loffset:
 	.quad	0x100000
 .Lmvsize:

arch/s390/boot/head.S

@@ -311,7 +311,6 @@ ENTRY(startup_kdump)
 	spt	6f-.LPG0(%r13)
 	mvc	__LC_LAST_UPDATE_TIMER(8),6f-.LPG0(%r13)
 	l	%r15,.Lstack-.LPG0(%r13)
-	ahi	%r15,-STACK_FRAME_OVERHEAD
 	brasl	%r14,verify_facilities
 #ifdef CONFIG_KERNEL_UNCOMPRESSED
 	jg	startup_continue
@@ -320,7 +319,7 @@ ENTRY(startup_kdump)
 #endif
 
 .Lstack:
-	.long	0x8000 + (1<<(PAGE_SHIFT+THREAD_SIZE_ORDER))
+	.long	0x8000 + THREAD_SIZE - STACK_FRAME_OVERHEAD
 	.align	8
 6:	.long	0x7fffffff,0xffffffff
 

arch/s390/kernel/head64.S

@@ -14,6 +14,7 @@
 #include <asm/asm-offsets.h>
 #include <asm/thread_info.h>
 #include <asm/page.h>
+#include <asm/ptrace.h>
 
 __HEAD
 ENTRY(startup_continue)
@@ -35,10 +36,9 @@ ENTRY(startup_continue)
 #
 	larl	%r14,init_task
 	stg	%r14,__LC_CURRENT
-	larl	%r15,init_thread_union
-	aghi	%r15,1<<(PAGE_SHIFT+THREAD_SIZE_ORDER) # init_task_union + THREAD_SIZE
+	larl	%r15,init_thread_union+THREAD_SIZE
 	stg	%r15,__LC_KERNEL_STACK	# set end of kernel stack
-	aghi	%r15,-160
+	aghi	%r15,-STACK_FRAME_OVERHEAD
 #
 # Early setup functions that may not rely on an initialized bss section,
 # like moving the initrd. Returns with an initialized bss section.

arch/s390/kernel/swsusp.S

@@ -197,9 +197,7 @@ pgm_check_entry:
 	brc	2,3b				/* busy, try again */
 
 	/* Suspend CPU not available -> panic */
-	larl	%r15,init_thread_union
-	aghi	%r15,1<<(PAGE_SHIFT+THREAD_SIZE_ORDER)
-	aghi	%r15,-STACK_FRAME_OVERHEAD
+	larl	%r15,init_thread_union+THREAD_SIZE-STACK_FRAME_OVERHEAD
 	larl	%r2,.Lpanic_string
 	brasl	%r14,sclp_early_printk_force
 	larl	%r3,.Ldisabled_wait_31

arch/s390/purgatory/head.S

@@ -11,6 +11,7 @@
 #include <asm/asm-offsets.h>
 #include <asm/page.h>
 #include <asm/sigp.h>
+#include <asm/ptrace.h>
 
 /* The purgatory is the code running between two kernels. It's main purpose
  * is to verify that the next kernel was not corrupted after load and to
@@ -88,8 +89,7 @@ ENTRY(purgatory_start)
 .base_crash:
 
 	/* Setup stack */
-	larl	%r15,purgatory_end
-	aghi	%r15,-160
+	larl	%r15,purgatory_end-STACK_FRAME_OVERHEAD
 
 	/* If the next kernel is KEXEC_TYPE_CRASH the purgatory is called
 	 * directly with a flag passed in %r2 whether the purgatory shall do