/* -*- mode: asm -*- * * linux/arch/m68k/kernel/entry.S * * Copyright (C) 1991, 1992 Linus Torvalds * * This file is subject to the terms and conditions of the GNU General Public * License. See the file README.legal in the main directory of this archive * for more details. * * 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 #include #include #include #include #include #include #include .globl system_call, buserr, trap, resume .globl sys_call_table .globl sys_fork, sys_clone, sys_vfork .globl ret_from_interrupt, bad_interrupt .globl auto_irqhandler_fixup .globl user_irqvec_fixup, user_irqhandler_fixup .text ENTRY(buserr) SAVE_ALL_INT GET_CURRENT(%d0) movel %sp,%sp@- | stack frame pointer argument bsrl buserr_c addql #4,%sp jra .Lret_from_exception ENTRY(trap) SAVE_ALL_INT GET_CURRENT(%d0) movel %sp,%sp@- | stack frame pointer argument bsrl trap_c addql #4,%sp jra .Lret_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_SMP ENTRY(ret_from_fork) movel %d1,%sp@- jsr schedule_tail addql #4,%sp jra .Lret_from_exception do_trace_entry: movel #-ENOSYS,%sp@(PT_OFF_D0)| needed for strace subql #4,%sp SAVE_SWITCH_STACK jbsr syscall_trace RESTORE_SWITCH_STACK addql #4,%sp movel %sp@(PT_OFF_ORIG_D0),%d0 cmpl #NR_syscalls,%d0 jcs syscall badsys: movel #-ENOSYS,%sp@(PT_OFF_D0) jra ret_from_syscall do_trace_exit: subql #4,%sp SAVE_SWITCH_STACK jbsr syscall_trace RESTORE_SWITCH_STACK addql #4,%sp jra .Lret_from_exception ENTRY(ret_from_signal) tstb %curptr@(TASK_INFO+TINFO_FLAGS+2) jge 1f jbsr syscall_trace 1: RESTORE_SWITCH_STACK addql #4,%sp /* on 68040 complete pending writebacks if any */ #ifdef CONFIG_M68040 bfextu %sp@(PT_OFF_FORMATVEC){#0,#4},%d0 subql #7,%d0 | bus error frame ? jbne 1f movel %sp,%sp@- jbsr berr_040cleanup addql #4,%sp 1: #endif jra .Lret_from_exception ENTRY(system_call) SAVE_ALL_SYS GET_CURRENT(%d1) | save top of frame movel %sp,%curptr@(TASK_THREAD+THREAD_ESP0) | syscall trace? tstb %curptr@(TASK_INFO+TINFO_FLAGS+2) jmi do_trace_entry cmpl #NR_syscalls,%d0 jcc badsys syscall: jbsr @(sys_call_table,%d0:l:4)@(0) movel %d0,%sp@(PT_OFF_D0) | save the return value ret_from_syscall: |oriw #0x0700,%sr movew %curptr@(TASK_INFO+TINFO_FLAGS+2),%d0 jne syscall_exit_work 1: 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 jmi 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: moveb %curptr@(TASK_INFO+TINFO_FLAGS+3),%d0 jne exit_work 1: RESTORE_ALL exit_work: | save top of frame movel %sp,%curptr@(TASK_THREAD+THREAD_ESP0) lslb #1,%d0 jmi 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_signal 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) addqb #1,%curptr@(TASK_INFO+TINFO_PREEMPT+1) | 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 stack auto_irqhandler_fixup = . + 2 jsr do_IRQ | process the IRQ addql #8,%sp | pop parameters off stack ret_from_interrupt: subqb #1,%curptr@(TASK_INFO+TINFO_PREEMPT+1) jeq ret_from_last_interrupt 2: RESTORE_ALL ALIGN ret_from_last_interrupt: moveq #(~ALLOWINT>>8)&0xff,%d0 andb %sp@(PT_OFF_SR),%d0 jne 2b /* check if we need to do software interrupts */ tstl irq_stat+CPUSTAT_SOFTIRQ_PENDING jeq .Lret_from_exception pea ret_from_exception jra do_softirq /* Handler for user defined interrupt vectors */ ENTRY(user_inthandler) SAVE_ALL_INT GET_CURRENT(%d0) addqb #1,%curptr@(TASK_INFO+TINFO_PREEMPT+1) | put exception # in d0 bfextu %sp@(PT_OFF_FORMATVEC){#4,#10},%d0 user_irqvec_fixup = . + 2 subw #VEC_USER,%d0 movel %sp,%sp@- movel %d0,%sp@- | put vector # on stack user_irqhandler_fixup = . + 2 jsr do_IRQ | process the IRQ addql #8,%sp | pop parameters off stack subqb #1,%curptr@(TASK_INFO+TINFO_PREEMPT+1) jeq ret_from_last_interrupt RESTORE_ALL /* Handler for uninitialized and spurious interrupts */ ENTRY(bad_inthandler) SAVE_ALL_INT GET_CURRENT(%d0) addqb #1,%curptr@(TASK_INFO+TINFO_PREEMPT+1) movel %sp,%sp@- jsr handle_badint addql #4,%sp subqb #1,%curptr@(TASK_INFO+TINFO_PREEMPT+1) jeq ret_from_last_interrupt RESTORE_ALL ENTRY(sys_fork) SAVE_SWITCH_STACK pea %sp@(SWITCH_STACK_SIZE) jbsr m68k_fork addql #4,%sp RESTORE_SWITCH_STACK rts ENTRY(sys_clone) SAVE_SWITCH_STACK pea %sp@(SWITCH_STACK_SIZE) jbsr m68k_clone addql #4,%sp RESTORE_SWITCH_STACK rts ENTRY(sys_vfork) SAVE_SWITCH_STACK pea %sp@(SWITCH_STACK_SIZE) jbsr m68k_vfork addql #4,%sp RESTORE_SWITCH_STACK rts ENTRY(sys_sigreturn) SAVE_SWITCH_STACK jbsr do_sigreturn RESTORE_SWITCH_STACK rts ENTRY(sys_rt_sigreturn) SAVE_SWITCH_STACK jbsr do_rt_sigreturn RESTORE_SWITCH_STACK rts 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_FS) /* 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 #endif 2: 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 #endif 2: fmovemx %a1@(TASK_THREAD+THREAD_FPREG),%fp0-%fp7 fmoveml %a1@(TASK_THREAD+THREAD_FPCNTL),%fpcr/%fpsr/%fpiar 3: 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_FS),%a0 movec %a0,%sfc movec %a0,%dfc /* restore status register */ movew %a1@(TASK_THREAD+THREAD_SR),%sr rts