/* SPDX-License-Identifier: GPL-2.0-or-later * -*- mode: asm -*- * *  linux/arch/m68k/kernel/entry.S * *  Copyright (C) 1991, 1992  Linus Torvalds * * Linux/m68k support by Hamish Macdonald * * 68060 fixes by Jesper Skov * */ /* * entry.S  contains the system-call and fault low-level handling routines. * This also contains the timer-interrupt handler, as well as all interrupts * and faults that can result in a task-switch. * * NOTE: This code handles signal-recognition, which happens every time * after a timer-interrupt and after each system call. * */ /* * 12/03/96 Jes: Currently we only support m68k single-cpu systems, so *               all pointers that used to be 'current' are now entry *               number 0 in the 'current_set' list. * *  6/05/00 RZ:	 addedd writeback completion after return from sighandler *		 for 68040 */ #include <linux/linkage.h>#include <asm/errno.h>#include <asm/setup.h>#include <asm/traps.h>#include <asm/unistd.h>#include <asm/asm-offsets.h>#include <asm/entry.h> .globl system_call, buserr, trap, resume.globl sys_call_table.globl __sys_fork, __sys_clone, __sys_vfork.globl bad_interrupt.globl auto_irqhandler_fixup.globl user_irqvec_fixup .textENTRY(__sys_fork)	SAVE_SWITCH_STACK	jbsr	sys_fork	lea     %sp@(24),%sp	rts ENTRY(__sys_clone)	SAVE_SWITCH_STACK	pea	%sp@(SWITCH_STACK_SIZE)	jbsr	m68k_clone	lea     %sp@(28),%sp	rts ENTRY(__sys_vfork)	SAVE_SWITCH_STACK	jbsr	sys_vfork	lea     %sp@(24),%sp	rts ENTRY(__sys_clone3)	SAVE_SWITCH_STACK	pea	%sp@(SWITCH_STACK_SIZE)	jbsr	m68k_clone3	lea	%sp@(28),%sp	rts ENTRY(sys_sigreturn)	SAVE_SWITCH_STACK	movel	%sp,%a1			  	| switch_stack pointer	lea	%sp@(SWITCH_STACK_SIZE),%a0	| pt_regs pointer	lea     %sp@(-84),%sp			| leave a gap	movel	%a1,%sp@-	movel	%a0,%sp@-	jbsr	do_sigreturn	jra	1f				| shared with rt_sigreturn() ENTRY(sys_rt_sigreturn)	SAVE_SWITCH_STACK	movel	%sp,%a1			  	| switch_stack pointer	lea	%sp@(SWITCH_STACK_SIZE),%a0	| pt_regs pointer	lea     %sp@(-84),%sp			| leave a gap	movel	%a1,%sp@-	movel	%a0,%sp@-	| stack contents:	|   [original pt_regs address] [original switch_stack address]	|   [gap] [switch_stack] [pt_regs] [exception frame]	jbsr	do_rt_sigreturn 1:	| stack contents now:	|   [original pt_regs address] [original switch_stack address]	|   [unused part of the gap] [moved switch_stack] [moved pt_regs]	|   [replacement exception frame]	| return value of do_{rt_,}sigreturn() points to moved switch_stack. 	movel	%d0,%sp				| discard the leftover junk	RESTORE_SWITCH_STACK	| stack contents now is just [syscall return address] [pt_regs] [frame]	| return pt_regs.d0	movel	%sp@(PT_OFF_D0+4),%d0	rts ENTRY(buserr)	SAVE_ALL_INT	GET_CURRENT(%d0)	movel	%sp,%sp@-		| stack frame pointer argument	jbsr	buserr_c	addql	#4,%sp	jra	ret_from_exception ENTRY(trap)	SAVE_ALL_INT	GET_CURRENT(%d0)	movel	%sp,%sp@-		| stack frame pointer argument	jbsr	trap_c	addql	#4,%sp	jra	ret_from_exception 	| After a fork we jump here directly from resume,	| so that %d1 contains the previous task	| schedule_tail now used regardless of CONFIG_SMPENTRY(ret_from_fork)	movel	%d1,%sp@-	jsr	schedule_tail	addql	#4,%sp	jra	ret_from_exception ENTRY(ret_from_kernel_thread)	| a3 contains the kernel thread payload, d7 - its argument	movel	%d1,%sp@-	jsr	schedule_tail	movel	%d7,(%sp)	jsr	%a3@	addql	#4,%sp	jra	ret_from_exception #if defined(CONFIG_COLDFIRE) || !defined(CONFIG_MMU) #ifdef TRAP_DBG_INTERRUPT .globl dbginterruptENTRY(dbginterrupt)	SAVE_ALL_INT	GET_CURRENT(%d0)	movel	%sp,%sp@- 		/* stack frame pointer argument */	jsr	dbginterrupt_c	addql	#4,%sp	jra	ret_from_exception#endif ENTRY(reschedule)	/* save top of frame */	pea	%sp@	jbsr	set_esp0	addql	#4,%sp	pea	ret_from_exception	jmp	schedule ENTRY(ret_from_user_signal)	moveq #__NR_sigreturn,%d0	trap #0 ENTRY(ret_from_user_rt_signal)	movel #__NR_rt_sigreturn,%d0	trap #0 #else do_trace_entry:	movel	#-ENOSYS,%sp@(PT_OFF_D0)| needed for strace	subql	#4,%sp	SAVE_SWITCH_STACK	jbsr	syscall_trace_enter	RESTORE_SWITCH_STACK	addql	#4,%sp	addql	#1,%d0			| optimization for cmpil #-1,%d0	jeq	ret_from_syscall	movel	%sp@(PT_OFF_ORIG_D0),%d0	cmpl	#NR_syscalls,%d0	jcs	syscall	jra	ret_from_syscallbadsys:	movel	#-ENOSYS,%sp@(PT_OFF_D0)	jra	ret_from_syscall do_trace_exit:	subql	#4,%sp	SAVE_SWITCH_STACK	jbsr	syscall_trace_leave	RESTORE_SWITCH_STACK	addql	#4,%sp	jra	.Lret_from_exception ENTRY(system_call)	SAVE_ALL_SYS 	GET_CURRENT(%d1)	movel	%d1,%a1 	| save top of frame	movel	%sp,%curptr@(TASK_THREAD+THREAD_ESP0) 	| syscall trace?	tstb	%a1@(TINFO_FLAGS+2)	jmi	do_trace_entry	| seccomp filter active?	btst	#5,%a1@(TINFO_FLAGS+2)	bnes	do_trace_entry	cmpl	#NR_syscalls,%d0	jcc	badsyssyscall:	jbsr	@(sys_call_table,%d0:l:4)@(0)	movel	%d0,%sp@(PT_OFF_D0)	| save the return valueret_from_syscall:	|oriw	#0x0700,%sr	movel	%curptr@(TASK_STACK),%a1	movew	%a1@(TINFO_FLAGS+2),%d0	jne	syscall_exit_work1:	RESTORE_ALL syscall_exit_work:	btst	#5,%sp@(PT_OFF_SR)	| check if returning to kernel	bnes	1b			| if so, skip resched, signals	lslw	#1,%d0	jcs	do_trace_exit	jmi	do_delayed_trace	lslw	#8,%d0	jne	do_signal_return	pea	resume_userspace	jra	schedule  ENTRY(ret_from_exception).Lret_from_exception:	btst	#5,%sp@(PT_OFF_SR)	| check if returning to kernel	bnes	1f			| if so, skip resched, signals	| only allow interrupts when we are really the last one on the	| kernel stack, otherwise stack overflow can occur during	| heavy interrupt load	andw	#ALLOWINT,%sr resume_userspace:	movel	%curptr@(TASK_STACK),%a1	moveb	%a1@(TINFO_FLAGS+3),%d0	jne	exit_work1:	RESTORE_ALL exit_work:	| save top of frame	movel	%sp,%curptr@(TASK_THREAD+THREAD_ESP0)	lslb	#1,%d0	jne	do_signal_return	pea	resume_userspace	jra	schedule  do_signal_return:	|andw	#ALLOWINT,%sr	subql	#4,%sp			| dummy return address	SAVE_SWITCH_STACK	pea	%sp@(SWITCH_STACK_SIZE)	bsrl	do_notify_resume	addql	#4,%sp	RESTORE_SWITCH_STACK	addql	#4,%sp	jbra	resume_userspace do_delayed_trace:	bclr	#7,%sp@(PT_OFF_SR)	| clear trace bit in SR	pea	1			| send SIGTRAP	movel	%curptr,%sp@-	pea	LSIGTRAP	jbsr	send_sig	addql	#8,%sp	addql	#4,%sp	jbra	resume_userspace  /* This is the main interrupt handler for autovector interrupts */ ENTRY(auto_inthandler)	SAVE_ALL_INT	GET_CURRENT(%d0)					|  put exception # in d0	bfextu	%sp@(PT_OFF_FORMATVEC){#4,#10},%d0	subw	#VEC_SPUR,%d0 	movel	%sp,%sp@-	movel	%d0,%sp@-		|  put vector # on stackauto_irqhandler_fixup = . + 2	jsr	do_IRQ			|  process the IRQ	addql	#8,%sp			|  pop parameters off stack	jra	ret_from_exception /* Handler for user defined interrupt vectors */ ENTRY(user_inthandler)	SAVE_ALL_INT	GET_CURRENT(%d0)					|  put exception # in d0	bfextu	%sp@(PT_OFF_FORMATVEC){#4,#10},%d0user_irqvec_fixup = . + 2	subw	#VEC_USER,%d0 	movel	%sp,%sp@-	movel	%d0,%sp@-		|  put vector # on stack	jsr	do_IRQ			|  process the IRQ	addql	#8,%sp			|  pop parameters off stack	jra	ret_from_exception /* Handler for uninitialized and spurious interrupts */ ENTRY(bad_inthandler)	SAVE_ALL_INT	GET_CURRENT(%d0) 	movel	%sp,%sp@-	jsr	handle_badint	addql	#4,%sp	jra	ret_from_exception resume:	/*	 * Beware - when entering resume, prev (the current task) is	 * in a0, next (the new task) is in a1,so don't change these	 * registers until their contents are no longer needed.	 */ 	/* save sr */	movew	%sr,%a0@(TASK_THREAD+THREAD_SR) 	/* save fs (sfc,%dfc) (may be pointing to kernel memory) */	movec	%sfc,%d0	movew	%d0,%a0@(TASK_THREAD+THREAD_FC) 	/* save usp */	/* it is better to use a movel here instead of a movew 8*) */	movec	%usp,%d0	movel	%d0,%a0@(TASK_THREAD+THREAD_USP) 	/* save non-scratch registers on stack */	SAVE_SWITCH_STACK 	/* save current kernel stack pointer */	movel	%sp,%a0@(TASK_THREAD+THREAD_KSP) 	/* save floating point context */#ifndef CONFIG_M68KFPU_EMU_ONLY#ifdef CONFIG_M68KFPU_EMU	tstl	m68k_fputype	jeq	3f#endif	fsave	%a0@(TASK_THREAD+THREAD_FPSTATE) #if defined(CONFIG_M68060)#if !defined(CPU_M68060_ONLY)	btst	#3,m68k_cputype+3	beqs	1f#endif	/* The 060 FPU keeps status in bits 15-8 of the first longword */	tstb	%a0@(TASK_THREAD+THREAD_FPSTATE+2)	jeq	3f#if !defined(CPU_M68060_ONLY)	jra	2f#endif#endif /* CONFIG_M68060 */#if !defined(CPU_M68060_ONLY)1:	tstb	%a0@(TASK_THREAD+THREAD_FPSTATE)	jeq	3f#endif2:	fmovemx	%fp0-%fp7,%a0@(TASK_THREAD+THREAD_FPREG)	fmoveml	%fpcr/%fpsr/%fpiar,%a0@(TASK_THREAD+THREAD_FPCNTL)3:#endif	/* CONFIG_M68KFPU_EMU_ONLY */	/* Return previous task in %d1 */	movel	%curptr,%d1 	/* switch to new task (a1 contains new task) */	movel	%a1,%curptr 	/* restore floating point context */#ifndef CONFIG_M68KFPU_EMU_ONLY#ifdef CONFIG_M68KFPU_EMU	tstl	m68k_fputype	jeq	4f#endif#if defined(CONFIG_M68060)#if !defined(CPU_M68060_ONLY)	btst	#3,m68k_cputype+3	beqs	1f#endif	/* The 060 FPU keeps status in bits 15-8 of the first longword */	tstb	%a1@(TASK_THREAD+THREAD_FPSTATE+2)	jeq	3f#if !defined(CPU_M68060_ONLY)	jra	2f#endif#endif /* CONFIG_M68060 */#if !defined(CPU_M68060_ONLY)1:	tstb	%a1@(TASK_THREAD+THREAD_FPSTATE)	jeq	3f#endif2:	fmovemx	%a1@(TASK_THREAD+THREAD_FPREG),%fp0-%fp7	fmoveml	%a1@(TASK_THREAD+THREAD_FPCNTL),%fpcr/%fpsr/%fpiar3:	frestore %a1@(TASK_THREAD+THREAD_FPSTATE)4:#endif	/* CONFIG_M68KFPU_EMU_ONLY */ 	/* restore the kernel stack pointer */	movel	%a1@(TASK_THREAD+THREAD_KSP),%sp 	/* restore non-scratch registers */	RESTORE_SWITCH_STACK 	/* restore user stack pointer */	movel	%a1@(TASK_THREAD+THREAD_USP),%a0	movel	%a0,%usp 	/* restore fs (sfc,%dfc) */	movew	%a1@(TASK_THREAD+THREAD_FC),%a0	movec	%a0,%sfc	movec	%a0,%dfc 	/* restore status register */	movew	%a1@(TASK_THREAD+THREAD_SR),%d0	oriw	#0x0700,%d0	movew	%d0,%sr 	rts #endif /* CONFIG_MMU && !CONFIG_COLDFIRE */