/* -*- 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 <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 .text ENTRY(__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_SMP ENTRY(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 dbginterrupt ENTRY(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 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_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 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 movel %curptr@(TASK_STACK),%a1 movew %a1@(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 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_work 1: 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 stack auto_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},%d0 user_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 #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_FC),%a0 movec %a0,%sfc movec %a0,%dfc /* restore status register */ movew %a1@(TASK_THREAD+THREAD_SR),%sr rts #endif /* CONFIG_MMU && !CONFIG_COLDFIRE */