s390: move thread_info into task_struct

This is the s390 variant of commit 15f4eae7 ("x86: Move
thread_info into task_struct").
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

arch/s390/Kconfig

@@ -169,6 +169,7 @@ config S390
 	select OLD_SIGSUSPEND3
 	select SPARSE_IRQ
 	select SYSCTL_EXCEPTION_TRACE
+	select THREAD_INFO_IN_TASK
 	select TTY
 	select VIRT_CPU_ACCOUNTING
 	select VIRT_TO_BUS

arch/s390/include/asm/lowcore.h

@@ -95,7 +95,7 @@ struct lowcore {
 
 	/* Current process. */
 	__u64	current_task;			/* 0x0310 */
-	__u64	thread_info;			/* 0x0318 */
+	__u8	pad_0x318[0x320-0x318];		/* 0x0318 */
 	__u64	kernel_stack;			/* 0x0320 */
 
 	/* Interrupt, panic and restart stack. */

arch/s390/include/asm/thread_info.h

@@ -30,10 +30,8 @@
  * - if the contents of this structure are changed, the assembly constants must also be changed
  */
 struct thread_info {
-	struct task_struct	*task;		/* main task structure */
 	unsigned long		flags;		/* low level flags */
 	unsigned long		sys_call_table;	/* System call table address */
-	unsigned int		cpu;		/* current CPU */
 	unsigned int		system_call;
 	__u64			user_timer;
 	__u64			system_timer;
@@ -45,20 +43,11 @@ struct thread_info {
  */
 #define INIT_THREAD_INFO(tsk)			\
 {						\
-	.task		= &tsk,			\
 	.flags		= 0,			\
-	.cpu		= 0,			\
 }
 
-#define init_thread_info	(init_thread_union.thread_info)
 #define init_stack		(init_thread_union.stack)
 
-/* how to get the thread information struct from C */
-static inline struct thread_info *current_thread_info(void)
-{
-	return (struct thread_info *) S390_lowcore.thread_info;
-}
-
 void arch_release_task_struct(struct task_struct *tsk);
 int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src);
 

arch/s390/kernel/asm-offsets.c

@@ -25,7 +25,7 @@
 int main(void)
 {
 	/* task struct offsets */
-	OFFSET(__TASK_thread_info, task_struct, stack);
+	OFFSET(__TASK_stack, task_struct, stack);
 	OFFSET(__TASK_thread, task_struct, thread);
 	OFFSET(__TASK_pid, task_struct, pid);
 	BLANK();
@@ -39,13 +39,11 @@ int main(void)
 	OFFSET(__THREAD_trap_tdb, thread_struct, trap_tdb);
 	BLANK();
 	/* thread info offsets */
-	OFFSET(__TI_task, thread_info, task);
-	OFFSET(__TI_flags, thread_info, flags);
-	OFFSET(__TI_sysc_table, thread_info, sys_call_table);
-	OFFSET(__TI_cpu, thread_info, cpu);
-	OFFSET(__TI_user_timer, thread_info, user_timer);
-	OFFSET(__TI_system_timer, thread_info, system_timer);
-	OFFSET(__TI_last_break, thread_info, last_break);
+	OFFSET(__TI_flags, task_struct, thread_info.flags);
+	OFFSET(__TI_sysc_table,  task_struct, thread_info.sys_call_table);
+	OFFSET(__TI_user_timer, task_struct, thread_info.user_timer);
+	OFFSET(__TI_system_timer, task_struct, thread_info.system_timer);
+	OFFSET(__TI_last_break, task_struct, thread_info.last_break);
 	BLANK();
 	/* pt_regs offsets */
 	OFFSET(__PT_ARGS, pt_regs, args);
@@ -160,7 +158,6 @@ int main(void)
 	OFFSET(__LC_INT_CLOCK, lowcore, int_clock);
 	OFFSET(__LC_MCCK_CLOCK, lowcore, mcck_clock);
 	OFFSET(__LC_CURRENT, lowcore, current_task);
-	OFFSET(__LC_THREAD_INFO, lowcore, thread_info);
 	OFFSET(__LC_KERNEL_STACK, lowcore, kernel_stack);
 	OFFSET(__LC_ASYNC_STACK, lowcore, async_stack);
 	OFFSET(__LC_PANIC_STACK, lowcore, panic_stack);

arch/s390/kernel/entry.S

@@ -186,14 +186,13 @@ ENTRY(__switch_to)
 	stmg	%r6,%r15,__SF_GPRS(%r15)	# store gprs of prev task
 	lgr	%r1,%r2
 	aghi	%r1,__TASK_thread		# thread_struct of prev task
-	lg	%r5,__TASK_thread_info(%r3)	# get thread_info of next
+	lg	%r5,__TASK_stack(%r3)		# start of kernel stack of next
 	stg	%r15,__THREAD_ksp(%r1)		# store kernel stack of prev
 	lgr	%r1,%r3
 	aghi	%r1,__TASK_thread		# thread_struct of next task
 	lgr	%r15,%r5
 	aghi	%r15,STACK_INIT			# end of kernel stack of next
 	stg	%r3,__LC_CURRENT		# store task struct of next
-	stg	%r5,__LC_THREAD_INFO		# store thread info of next
 	stg	%r15,__LC_KERNEL_STACK		# store end of kernel stack
 	lg	%r15,__THREAD_ksp(%r1)		# load kernel stack of next
 	/* c4 is used in guest detection: arch/s390/kernel/perf_cpum_sf.c */
@@ -274,7 +273,7 @@ ENTRY(system_call)
 .Lsysc_stmg:
 	stmg	%r8,%r15,__LC_SAVE_AREA_SYNC
 	lg	%r10,__LC_LAST_BREAK
-	lg	%r12,__LC_THREAD_INFO
+	lg	%r12,__LC_CURRENT
 	lghi	%r14,_PIF_SYSCALL
 .Lsysc_per:
 	lg	%r15,__LC_KERNEL_STACK
@@ -457,7 +456,7 @@ ENTRY(system_call)
 #
 ENTRY(ret_from_fork)
 	la	%r11,STACK_FRAME_OVERHEAD(%r15)
-	lg	%r12,__LC_THREAD_INFO
+	lg	%r12,__LC_CURRENT
 	brasl	%r14,schedule_tail
 	TRACE_IRQS_ON
 	ssm	__LC_SVC_NEW_PSW	# reenable interrupts
@@ -478,7 +477,7 @@ ENTRY(pgm_check_handler)
 	stpt	__LC_SYNC_ENTER_TIMER
 	stmg	%r8,%r15,__LC_SAVE_AREA_SYNC
 	lg	%r10,__LC_LAST_BREAK
-	lg	%r12,__LC_THREAD_INFO
+	lg	%r12,__LC_CURRENT
 	larl	%r13,cleanup_critical
 	lmg	%r8,%r9,__LC_PGM_OLD_PSW
 	tmhh	%r8,0x0001		# test problem state bit
@@ -501,7 +500,7 @@ ENTRY(pgm_check_handler)
 2:	LAST_BREAK %r14
 	UPDATE_VTIME %r14,%r15,__LC_SYNC_ENTER_TIMER
 	lg	%r15,__LC_KERNEL_STACK
-	lg	%r14,__TI_task(%r12)
+	lgr	%r14,%r12
 	aghi	%r14,__TASK_thread	# pointer to thread_struct
 	lghi	%r13,__LC_PGM_TDB
 	tm	__LC_PGM_ILC+2,0x02	# check for transaction abort
@@ -567,7 +566,7 @@ ENTRY(io_int_handler)
 	stpt	__LC_ASYNC_ENTER_TIMER
 	stmg	%r8,%r15,__LC_SAVE_AREA_ASYNC
 	lg	%r10,__LC_LAST_BREAK
-	lg	%r12,__LC_THREAD_INFO
+	lg	%r12,__LC_CURRENT
 	larl	%r13,cleanup_critical
 	lmg	%r8,%r9,__LC_IO_OLD_PSW
 	SWITCH_ASYNC __LC_SAVE_AREA_ASYNC,__LC_ASYNC_ENTER_TIMER
@@ -741,7 +740,7 @@ ENTRY(ext_int_handler)
 	stpt	__LC_ASYNC_ENTER_TIMER
 	stmg	%r8,%r15,__LC_SAVE_AREA_ASYNC
 	lg	%r10,__LC_LAST_BREAK
-	lg	%r12,__LC_THREAD_INFO
+	lg	%r12,__LC_CURRENT
 	larl	%r13,cleanup_critical
 	lmg	%r8,%r9,__LC_EXT_OLD_PSW
 	SWITCH_ASYNC __LC_SAVE_AREA_ASYNC,__LC_ASYNC_ENTER_TIMER
@@ -889,7 +888,7 @@ ENTRY(mcck_int_handler)
 	spt	__LC_CPU_TIMER_SAVE_AREA-4095(%r1)	# revalidate cpu timer
 	lmg	%r0,%r15,__LC_GPREGS_SAVE_AREA-4095(%r1)# revalidate gprs
 	lg	%r10,__LC_LAST_BREAK
-	lg	%r12,__LC_THREAD_INFO
+	lg	%r12,__LC_CURRENT
 	larl	%r13,cleanup_critical
 	lmg	%r8,%r9,__LC_MCK_OLD_PSW
 	TSTMSK	__LC_MCCK_CODE,MCCK_CODE_SYSTEM_DAMAGE

arch/s390/kernel/head64.S

@@ -32,10 +32,9 @@ ENTRY(startup_continue)
 #
 # Setup stack
 #
-	larl	%r15,init_thread_union
-	stg	%r15,__LC_THREAD_INFO	# cache thread info in lowcore
-	lg	%r14,__TI_task(%r15)	# cache current in lowcore
+	larl	%r14,init_task
 	stg	%r14,__LC_CURRENT
+	larl	%r15,init_thread_union
 	aghi	%r15,1<<(PAGE_SHIFT+THREAD_ORDER) # init_task_union + THREAD_SIZE
 	stg	%r15,__LC_KERNEL_STACK	# set end of kernel stack
 	aghi	%r15,-160

arch/s390/kernel/setup.c

@@ -329,8 +329,7 @@ static void __init setup_lowcore(void)
 	lc->panic_stack = (unsigned long)
 		__alloc_bootmem(PAGE_SIZE, PAGE_SIZE, 0)
 		+ PAGE_SIZE - STACK_FRAME_OVERHEAD - sizeof(struct pt_regs);
-	lc->current_task = (unsigned long) init_thread_union.thread_info.task;
-	lc->thread_info = (unsigned long) &init_thread_union;
+	lc->current_task = (unsigned long)&init_task;
 	lc->lpp = LPP_MAGIC;
 	lc->machine_flags = S390_lowcore.machine_flags;
 	lc->preempt_count = S390_lowcore.preempt_count;

arch/s390/kernel/smp.c

@@ -263,7 +263,6 @@ static void pcpu_attach_task(struct pcpu *pcpu, struct task_struct *tsk)
 
 	lc->kernel_stack = (unsigned long) task_stack_page(tsk)
 		+ THREAD_SIZE - STACK_FRAME_OVERHEAD - sizeof(struct pt_regs);
-	lc->thread_info = (unsigned long) task_thread_info(tsk);
 	lc->current_task = (unsigned long) tsk;
 	lc->lpp = LPP_MAGIC;
 	lc->current_pid = tsk->pid;