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

/*
 *  arch/s390/kernel/entry.S
 *    S390 low-level entry points.
 *
 *  S390 version
 *    Copyright (C) 1999,2000 IBM Deutschland Entwicklung GmbH, IBM Corporation
 *    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/sys.h>
#include <linux/linkage.h>
#include <linux/config.h>
#include <asm/cache.h>
#include <asm/lowcore.h>
#include <asm/errno.h>
#include <asm/ptrace.h>
#include <asm/thread_info.h>
#include <asm/offsets.h>
#include <asm/unistd.h>
#include <asm/page.h>

/*
 * Stack layout for the system_call stack entry.
 * The first few entries are identical to the user_regs_struct.
 */
SP_PTREGS    =  STACK_FRAME_OVERHEAD
SP_ARGS      =  STACK_FRAME_OVERHEAD + __PT_ARGS
SP_PSW       =  STACK_FRAME_OVERHEAD + __PT_PSW
SP_R0        =  STACK_FRAME_OVERHEAD + __PT_GPRS
SP_R1        =  STACK_FRAME_OVERHEAD + __PT_GPRS + 4
SP_R2        =  STACK_FRAME_OVERHEAD + __PT_GPRS + 8
SP_R3        =  STACK_FRAME_OVERHEAD + __PT_GPRS + 12
SP_R4        =  STACK_FRAME_OVERHEAD + __PT_GPRS + 16
SP_R5        =  STACK_FRAME_OVERHEAD + __PT_GPRS + 20
SP_R6        =  STACK_FRAME_OVERHEAD + __PT_GPRS + 24
SP_R7        =  STACK_FRAME_OVERHEAD + __PT_GPRS + 28
SP_R8        =  STACK_FRAME_OVERHEAD + __PT_GPRS + 32
SP_R9        =  STACK_FRAME_OVERHEAD + __PT_GPRS + 36
SP_R10       =  STACK_FRAME_OVERHEAD + __PT_GPRS + 40
SP_R11       =  STACK_FRAME_OVERHEAD + __PT_GPRS + 44
SP_R12       =  STACK_FRAME_OVERHEAD + __PT_GPRS + 48
SP_R13       =  STACK_FRAME_OVERHEAD + __PT_GPRS + 52
SP_R14       =  STACK_FRAME_OVERHEAD + __PT_GPRS + 56
SP_R15       =  STACK_FRAME_OVERHEAD + __PT_GPRS + 60
SP_ORIG_R2   =  STACK_FRAME_OVERHEAD + __PT_ORIG_GPR2
SP_ILC       =  STACK_FRAME_OVERHEAD + __PT_ILC
SP_TRAP      =  STACK_FRAME_OVERHEAD + __PT_TRAP
SP_SIZE      =  STACK_FRAME_OVERHEAD + __PT_SIZE

_TIF_WORK_SVC = (_TIF_SIGPENDING | _TIF_NEED_RESCHED | _TIF_MCCK_PENDING | \
		 _TIF_RESTART_SVC | _TIF_SINGLE_STEP )
_TIF_WORK_INT = (_TIF_SIGPENDING | _TIF_NEED_RESCHED | _TIF_MCCK_PENDING)

STACK_SHIFT = PAGE_SHIFT + THREAD_ORDER
STACK_SIZE  = 1 << STACK_SHIFT

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

/*
 * Register usage in interrupt handlers:
 *    R9  - pointer to current task structure
 *    R13 - pointer to literal pool
 *    R14 - return register for function calls
 *    R15 - kernel stack pointer
 */

	.macro  STORE_TIMER lc_offset
#ifdef CONFIG_VIRT_CPU_ACCOUNTING
	stpt	\lc_offset
#endif
	.endm

#ifdef CONFIG_VIRT_CPU_ACCOUNTING
	.macro  UPDATE_VTIME lc_from,lc_to,lc_sum
	lm	%r10,%r11,\lc_from
	sl	%r10,\lc_to
	sl	%r11,\lc_to+4
	bc	3,BASED(0f)
	sl	%r10,BASED(.Lc_1)
0:	al	%r10,\lc_sum
	al	%r11,\lc_sum+4
	bc	12,BASED(1f)
	al	%r10,BASED(.Lc_1)
1:	stm	%r10,%r11,\lc_sum
	.endm
#endif

	.macro	SAVE_ALL_BASE savearea
	stm	%r12,%r15,\savearea
	l	%r13,__LC_SVC_NEW_PSW+4	# load &system_call to %r13
	.endm

	.macro	SAVE_ALL psworg,savearea,sync
	la	%r12,\psworg
	.if	\sync
	tm	\psworg+1,0x01		# test problem state bit
	bz	BASED(2f)		# skip stack setup save
	l	%r15,__LC_KERNEL_STACK	# problem state -> load ksp
	.else
	tm	\psworg+1,0x01		# test problem state bit
	bnz	BASED(1f)		# from user -> load async stack
	clc	\psworg+4(4),BASED(.Lcritical_end)
	bhe	BASED(0f)
	clc	\psworg+4(4),BASED(.Lcritical_start)
	bl	BASED(0f)
	l	%r14,BASED(.Lcleanup_critical)
	basr	%r14,%r14
	tm	0(%r12),0x01		# retest problem state after cleanup
	bnz	BASED(1f)
0:	l	%r14,__LC_ASYNC_STACK	# are we already on the async stack ?
	slr	%r14,%r15
	sra	%r14,STACK_SHIFT
	be	BASED(2f)
1:	l	%r15,__LC_ASYNC_STACK
	.endif
#ifdef CONFIG_CHECK_STACK
	b	BASED(3f)
2:	tml	%r15,STACK_SIZE - CONFIG_STACK_GUARD
	bz	BASED(stack_overflow)
3:
#endif
2:
	.endm

	.macro  CREATE_STACK_FRAME psworg,savearea
	s	%r15,BASED(.Lc_spsize)	# make room for registers & psw
	mvc	SP_PSW(8,%r15),0(%r12)	# move user PSW to stack
	la	%r12,\psworg
	st	%r2,SP_ORIG_R2(%r15)	# store original content of gpr 2
	icm	%r12,12,__LC_SVC_ILC
	stm	%r0,%r11,SP_R0(%r15)	# store gprs %r0-%r11 to kernel stack
	st	%r12,SP_ILC(%r15)
	mvc	SP_R12(16,%r15),\savearea # move %r12-%r15 to stack
	la	%r12,0
	st	%r12,__SF_BACKCHAIN(%r15)	# clear back chain
	.endm

	.macro  RESTORE_ALL sync
	mvc	__LC_RETURN_PSW(8),SP_PSW(%r15) # move user PSW to lowcore