path: root/arch/s390/kernel/entry.S

/*
 *  arch/s390/kernel/entry.S
 *    S390 low-level entry points.
 *
 *    Copyright (C) IBM Corp. 1999,2012
 *    Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com),
 *		 Hartmut Penner (hp@de.ibm.com),
 *		 Denis Joseph Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com),
 *		 Heiko Carstens <heiko.carstens@de.ibm.com>
 */

#include <linux/init.h>
#include <linux/linkage.h>
#include <asm/cache.h>
#include <asm/errno.h>
#include <asm/ptrace.h>
#include <asm/thread_info.h>
#include <asm/asm-offsets.h>
#include <asm/unistd.h>
#include <asm/page.h>

__PT_R0      =	__PT_GPRS
__PT_R1      =	__PT_GPRS + 4
__PT_R2      =	__PT_GPRS + 8
__PT_R3      =	__PT_GPRS + 12
__PT_R4      =	__PT_GPRS + 16
__PT_R5      =	__PT_GPRS + 20
__PT_R6      =	__PT_GPRS + 24
__PT_R7      =	__PT_GPRS + 28
__PT_R8      =	__PT_GPRS + 32
__PT_R9      =	__PT_GPRS + 36
__PT_R10     =	__PT_GPRS + 40
__PT_R11     =	__PT_GPRS + 44
__PT_R12     =	__PT_GPRS + 48
__PT_R13     =	__PT_GPRS + 524
__PT_R14     =	__PT_GPRS + 56
__PT_R15     =	__PT_GPRS + 60

_TIF_WORK_SVC = (_TIF_SIGPENDING | _TIF_NOTIFY_RESUME | _TIF_NEED_RESCHED | \
		 _TIF_MCCK_PENDING | _TIF_PER_TRAP )
_TIF_WORK_INT = (_TIF_SIGPENDING | _TIF_NOTIFY_RESUME | _TIF_NEED_RESCHED | \
		 _TIF_MCCK_PENDING)
_TIF_TRACE    = (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | _TIF_SECCOMP | \
		 _TIF_SYSCALL_TRACEPOINT)

STACK_SHIFT = PAGE_SHIFT + THREAD_ORDER
STACK_SIZE  = 1 << STACK_SHIFT

#define BASED(name) name-system_call(%r13)

	.macro	TRACE_IRQS_ON
#ifdef CONFIG_TRACE_IRQFLAGS
	basr	%r2,%r0
	l	%r1,BASED(.Lhardirqs_on)
	basr	%r14,%r1		# call trace_hardirqs_on_caller
#endif
	.endm

	.macro	TRACE_IRQS_OFF
#ifdef CONFIG_TRACE_IRQFLAGS
	basr	%r2,%r0
	l	%r1,BASED(.Lhardirqs_off)
	basr	%r14,%r1		# call trace_hardirqs_off_caller
#endif
	.endm

	.macro	LOCKDEP_SYS_EXIT
#ifdef CONFIG_LOCKDEP
	tm	__PT_PSW+1(%r11),0x01	# returning to user ?
	jz	.+10
	l	%r1,BASED(.Llockdep_sys_exit)
	basr	%r14,%r1		# call lockdep_sys_exit
#endif
	.endm

	.macro	CHECK_STACK stacksize,savearea
#ifdef CONFIG_CHECK_STACK
	tml	%r15,\stacksize - CONFIG_STACK_GUARD
	la	%r14,\savearea
	jz	stack_overflow
#endif
	.endm

	.macro	SWITCH_ASYNC savearea,stack,shift
	tmh	%r8,0x0001		# interrupting from user ?
	jnz	1f
	lr	%r14,%r9
	sl	%r14,BASED(.Lcritical_start)
	cl	%r14,BASED(.Lcritical_length)
	jhe	0f
	la	%r11,\savearea		# inside critical section, do cleanup
	bras	%r14,cleanup_critical
	tmh	%r8,0x0001		# retest problem state after cleanup
	jnz	1f
0:	l	%r14,\stack		# are we already on the target stack?
	slr	%r14,%r15
	sra	%r14,\shift
	jnz	1f
	CHECK_STACK 1<<\shift,\savearea
	j	2f
1:	l	%r15,\stack		# load target stack
2:	ahi	%r15,-(STACK_FRAME_OVERHEAD + __PT_SIZE)
	la	%r11,STACK_FRAME_OVERHEAD(%r15)
	.endm

	.macro	ADD64 high,low,timer
	al	\high,\timer
	al	\low,4+\timer
	brc	12,.+8
	ahi	\high,1
	.endm

	.macro	SUB64 high,low,timer
	sl	\high,\timer
	sl	\low,4+\timer
	brc	3,.+8
	ahi	\high,-1
	.endm

	.macro	UPDATE_VTIME high,low,enter_timer
	lm	\high,\low,__LC_EXIT_TIMER
	SUB64	\high,\low,\enter_timer
	ADD64	\high,\low,__LC_USER_TIMER
	stm	\high,\low,__LC_USER_TIMER
	lm	\high,\low,__LC_LAST_UPDATE_TIMER
	SUB64	\high,\low,__LC_EXIT_TIMER
	ADD64	\high,\low,__LC_SYSTEM_TIMER
	stm	\high,\low,__LC_SYSTEM_TIMER
	mvc	__LC_LAST_UPDATE_TIMER(8),\enter_timer
	.endm

	.macro REENABLE_IRQS
	st	%r8,__LC_RETURN_PSW
	ni	__LC_RETURN_PSW,0xbf
	ssm	__LC_RETURN_PSW
	.endm

	.section .kprobes.text, "ax"

/*
 * Scheduler resume function, called by switch_to
 *  gpr2 = (task_struct *) prev
 *  gpr3 = (task_struct *) next
 * Returns:
 *  gpr2 = prev
 */
ENTRY(__switch_to)
	l	%r4,__THREAD_info(%r2)		# get thread_info of prev
	l	%r5,__THREAD_info(%r3)		# get thread_info of next
	tm	__TI_flags+3(%r4),_TIF_MCCK_PENDING # machine check pending?
	jz	0f
	ni	__TI_flags+3(%r4),255-_TIF_MCCK_PENDING	# clear flag in prev
	oi	__TI_flags+3(%r5),_TIF_MCCK_PENDING	# set it in next
0:	stm	%r6,%r15,__SF_GPRS(%r15)	# store gprs of prev task
	st	%r15,__THREAD_ksp(