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Diffstat (limited to 'arch/m68k/kernel/entry.S')
| -rw-r--r-- | arch/m68k/kernel/entry.S | 423 |
1 files changed, 423 insertions, 0 deletions
diff --git a/arch/m68k/kernel/entry.S b/arch/m68k/kernel/entry.S new file mode 100644 index 000000000..b54ac7aba --- /dev/null +++ b/arch/m68k/kernel/entry.S @@ -0,0 +1,423 @@ +/* -*- 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/segment.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_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 + +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 + 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) + movel %curptr@(TASK_STACK),%a1 + tstb %a1@(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) + 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_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 + +#endif /* CONFIG_MMU && !CONFIG_COLDFIRE */ |