1/* -*- mode: asm -*- 2 * 3 * linux/arch/m68k/kernel/entry.S 4 * 5 * Copyright (C) 1991, 1992 Linus Torvalds 6 * 7 * This file is subject to the terms and conditions of the GNU General Public 8 * License. See the file README.legal in the main directory of this archive 9 * for more details. 10 * 11 * Linux/m68k support by Hamish Macdonald 12 * 13 * 68060 fixes by Jesper Skov 14 * 15 */ 16 17/* 18 * entry.S contains the system-call and fault low-level handling routines. 19 * This also contains the timer-interrupt handler, as well as all interrupts 20 * and faults that can result in a task-switch. 21 * 22 * NOTE: This code handles signal-recognition, which happens every time 23 * after a timer-interrupt and after each system call. 24 * 25 */ 26 27/* 28 * 12/03/96 Jes: Currently we only support m68k single-cpu systems, so 29 * all pointers that used to be 'current' are now entry 30 * number 0 in the 'current_set' list. 31 * 32 * 6/05/00 RZ: addedd writeback completion after return from sighandler 33 * for 68040 34 */ 35 36#include <linux/linkage.h> 37#include <asm/errno.h> 38#include <asm/setup.h> 39#include <asm/segment.h> 40#include <asm/traps.h> 41#include <asm/unistd.h> 42#include <asm/asm-offsets.h> 43#include <asm/entry.h> 44 45.globl system_call, buserr, trap, resume 46.globl sys_call_table 47.globl __sys_fork, __sys_clone, __sys_vfork 48.globl bad_interrupt 49.globl auto_irqhandler_fixup 50.globl user_irqvec_fixup 51 52.text 53ENTRY(__sys_fork) 54 SAVE_SWITCH_STACK 55 jbsr sys_fork 56 lea %sp@(24),%sp 57 rts 58 59ENTRY(__sys_clone) 60 SAVE_SWITCH_STACK 61 pea %sp@(SWITCH_STACK_SIZE) 62 jbsr m68k_clone 63 lea %sp@(28),%sp 64 rts 65 66ENTRY(__sys_vfork) 67 SAVE_SWITCH_STACK 68 jbsr sys_vfork 69 lea %sp@(24),%sp 70 rts 71 72ENTRY(sys_sigreturn) 73 SAVE_SWITCH_STACK 74 jbsr do_sigreturn 75 RESTORE_SWITCH_STACK 76 rts 77 78ENTRY(sys_rt_sigreturn) 79 SAVE_SWITCH_STACK 80 jbsr do_rt_sigreturn 81 RESTORE_SWITCH_STACK 82 rts 83 84ENTRY(buserr) 85 SAVE_ALL_INT 86 GET_CURRENT(%d0) 87 movel %sp,%sp@- | stack frame pointer argument 88 jbsr buserr_c 89 addql #4,%sp 90 jra ret_from_exception 91 92ENTRY(trap) 93 SAVE_ALL_INT 94 GET_CURRENT(%d0) 95 movel %sp,%sp@- | stack frame pointer argument 96 jbsr trap_c 97 addql #4,%sp 98 jra ret_from_exception 99 100 | After a fork we jump here directly from resume, 101 | so that %d1 contains the previous task 102 | schedule_tail now used regardless of CONFIG_SMP 103ENTRY(ret_from_fork) 104 movel %d1,%sp@- 105 jsr schedule_tail 106 addql #4,%sp 107 jra ret_from_exception 108 109ENTRY(ret_from_kernel_thread) 110 | a3 contains the kernel thread payload, d7 - its argument 111 movel %d1,%sp@- 112 jsr schedule_tail 113 movel %d7,(%sp) 114 jsr %a3@ 115 addql #4,%sp 116 jra ret_from_exception 117 118#if defined(CONFIG_COLDFIRE) || !defined(CONFIG_MMU) 119 120#ifdef TRAP_DBG_INTERRUPT 121 122.globl dbginterrupt 123ENTRY(dbginterrupt) 124 SAVE_ALL_INT 125 GET_CURRENT(%d0) 126 movel %sp,%sp@- /* stack frame pointer argument */ 127 jsr dbginterrupt_c 128 addql #4,%sp 129 jra ret_from_exception 130#endif 131 132ENTRY(reschedule) 133 /* save top of frame */ 134 pea %sp@ 135 jbsr set_esp0 136 addql #4,%sp 137 pea ret_from_exception 138 jmp schedule 139 140ENTRY(ret_from_user_signal) 141 moveq #__NR_sigreturn,%d0 142 trap #0 143 144ENTRY(ret_from_user_rt_signal) 145 movel #__NR_rt_sigreturn,%d0 146 trap #0 147 148#else 149 150do_trace_entry: 151 movel #-ENOSYS,%sp@(PT_OFF_D0)| needed for strace 152 subql #4,%sp 153 SAVE_SWITCH_STACK 154 jbsr syscall_trace 155 RESTORE_SWITCH_STACK 156 addql #4,%sp 157 movel %sp@(PT_OFF_ORIG_D0),%d0 158 cmpl #NR_syscalls,%d0 159 jcs syscall 160badsys: 161 movel #-ENOSYS,%sp@(PT_OFF_D0) 162 jra ret_from_syscall 163 164do_trace_exit: 165 subql #4,%sp 166 SAVE_SWITCH_STACK 167 jbsr syscall_trace 168 RESTORE_SWITCH_STACK 169 addql #4,%sp 170 jra .Lret_from_exception 171 172ENTRY(ret_from_signal) 173 movel %curptr@(TASK_STACK),%a1 174 tstb %a1@(TINFO_FLAGS+2) 175 jge 1f 176 jbsr syscall_trace 1771: RESTORE_SWITCH_STACK 178 addql #4,%sp 179/* on 68040 complete pending writebacks if any */ 180#ifdef CONFIG_M68040 181 bfextu %sp@(PT_OFF_FORMATVEC){#0,#4},%d0 182 subql #7,%d0 | bus error frame ? 183 jbne 1f 184 movel %sp,%sp@- 185 jbsr berr_040cleanup 186 addql #4,%sp 1871: 188#endif 189 jra .Lret_from_exception 190 191ENTRY(system_call) 192 SAVE_ALL_SYS 193 194 GET_CURRENT(%d1) 195 movel %d1,%a1 196 197 | save top of frame 198 movel %sp,%curptr@(TASK_THREAD+THREAD_ESP0) 199 200 | syscall trace? 201 tstb %a1@(TINFO_FLAGS+2) 202 jmi do_trace_entry 203 cmpl #NR_syscalls,%d0 204 jcc badsys 205syscall: 206 jbsr @(sys_call_table,%d0:l:4)@(0) 207 movel %d0,%sp@(PT_OFF_D0) | save the return value 208ret_from_syscall: 209 |oriw #0x0700,%sr 210 movel %curptr@(TASK_STACK),%a1 211 movew %a1@(TINFO_FLAGS+2),%d0 212 jne syscall_exit_work 2131: RESTORE_ALL 214 215syscall_exit_work: 216 btst #5,%sp@(PT_OFF_SR) | check if returning to kernel 217 bnes 1b | if so, skip resched, signals 218 lslw #1,%d0 219 jcs do_trace_exit 220 jmi do_delayed_trace 221 lslw #8,%d0 222 jne do_signal_return 223 pea resume_userspace 224 jra schedule 225 226 227ENTRY(ret_from_exception) 228.Lret_from_exception: 229 btst #5,%sp@(PT_OFF_SR) | check if returning to kernel 230 bnes 1f | if so, skip resched, signals 231 | only allow interrupts when we are really the last one on the 232 | kernel stack, otherwise stack overflow can occur during 233 | heavy interrupt load 234 andw #ALLOWINT,%sr 235 236resume_userspace: 237 movel %curptr@(TASK_STACK),%a1 238 moveb %a1@(TINFO_FLAGS+3),%d0 239 jne exit_work 2401: RESTORE_ALL 241 242exit_work: 243 | save top of frame 244 movel %sp,%curptr@(TASK_THREAD+THREAD_ESP0) 245 lslb #1,%d0 246 jne do_signal_return 247 pea resume_userspace 248 jra schedule 249 250 251do_signal_return: 252 |andw #ALLOWINT,%sr 253 subql #4,%sp | dummy return address 254 SAVE_SWITCH_STACK 255 pea %sp@(SWITCH_STACK_SIZE) 256 bsrl do_notify_resume 257 addql #4,%sp 258 RESTORE_SWITCH_STACK 259 addql #4,%sp 260 jbra resume_userspace 261 262do_delayed_trace: 263 bclr #7,%sp@(PT_OFF_SR) | clear trace bit in SR 264 pea 1 | send SIGTRAP 265 movel %curptr,%sp@- 266 pea LSIGTRAP 267 jbsr send_sig 268 addql #8,%sp 269 addql #4,%sp 270 jbra resume_userspace 271 272 273/* This is the main interrupt handler for autovector interrupts */ 274 275ENTRY(auto_inthandler) 276 SAVE_ALL_INT 277 GET_CURRENT(%d0) 278 | put exception # in d0 279 bfextu %sp@(PT_OFF_FORMATVEC){#4,#10},%d0 280 subw #VEC_SPUR,%d0 281 282 movel %sp,%sp@- 283 movel %d0,%sp@- | put vector # on stack 284auto_irqhandler_fixup = . + 2 285 jsr do_IRQ | process the IRQ 286 addql #8,%sp | pop parameters off stack 287 jra ret_from_exception 288 289/* Handler for user defined interrupt vectors */ 290 291ENTRY(user_inthandler) 292 SAVE_ALL_INT 293 GET_CURRENT(%d0) 294 | put exception # in d0 295 bfextu %sp@(PT_OFF_FORMATVEC){#4,#10},%d0 296user_irqvec_fixup = . + 2 297 subw #VEC_USER,%d0 298 299 movel %sp,%sp@- 300 movel %d0,%sp@- | put vector # on stack 301 jsr do_IRQ | process the IRQ 302 addql #8,%sp | pop parameters off stack 303 jra ret_from_exception 304 305/* Handler for uninitialized and spurious interrupts */ 306 307ENTRY(bad_inthandler) 308 SAVE_ALL_INT 309 GET_CURRENT(%d0) 310 311 movel %sp,%sp@- 312 jsr handle_badint 313 addql #4,%sp 314 jra ret_from_exception 315 316resume: 317 /* 318 * Beware - when entering resume, prev (the current task) is 319 * in a0, next (the new task) is in a1,so don't change these 320 * registers until their contents are no longer needed. 321 */ 322 323 /* save sr */ 324 movew %sr,%a0@(TASK_THREAD+THREAD_SR) 325 326 /* save fs (sfc,%dfc) (may be pointing to kernel memory) */ 327 movec %sfc,%d0 328 movew %d0,%a0@(TASK_THREAD+THREAD_FS) 329 330 /* save usp */ 331 /* it is better to use a movel here instead of a movew 8*) */ 332 movec %usp,%d0 333 movel %d0,%a0@(TASK_THREAD+THREAD_USP) 334 335 /* save non-scratch registers on stack */ 336 SAVE_SWITCH_STACK 337 338 /* save current kernel stack pointer */ 339 movel %sp,%a0@(TASK_THREAD+THREAD_KSP) 340 341 /* save floating point context */ 342#ifndef CONFIG_M68KFPU_EMU_ONLY 343#ifdef CONFIG_M68KFPU_EMU 344 tstl m68k_fputype 345 jeq 3f 346#endif 347 fsave %a0@(TASK_THREAD+THREAD_FPSTATE) 348 349#if defined(CONFIG_M68060) 350#if !defined(CPU_M68060_ONLY) 351 btst #3,m68k_cputype+3 352 beqs 1f 353#endif 354 /* The 060 FPU keeps status in bits 15-8 of the first longword */ 355 tstb %a0@(TASK_THREAD+THREAD_FPSTATE+2) 356 jeq 3f 357#if !defined(CPU_M68060_ONLY) 358 jra 2f 359#endif 360#endif /* CONFIG_M68060 */ 361#if !defined(CPU_M68060_ONLY) 3621: tstb %a0@(TASK_THREAD+THREAD_FPSTATE) 363 jeq 3f 364#endif 3652: fmovemx %fp0-%fp7,%a0@(TASK_THREAD+THREAD_FPREG) 366 fmoveml %fpcr/%fpsr/%fpiar,%a0@(TASK_THREAD+THREAD_FPCNTL) 3673: 368#endif /* CONFIG_M68KFPU_EMU_ONLY */ 369 /* Return previous task in %d1 */ 370 movel %curptr,%d1 371 372 /* switch to new task (a1 contains new task) */ 373 movel %a1,%curptr 374 375 /* restore floating point context */ 376#ifndef CONFIG_M68KFPU_EMU_ONLY 377#ifdef CONFIG_M68KFPU_EMU 378 tstl m68k_fputype 379 jeq 4f 380#endif 381#if defined(CONFIG_M68060) 382#if !defined(CPU_M68060_ONLY) 383 btst #3,m68k_cputype+3 384 beqs 1f 385#endif 386 /* The 060 FPU keeps status in bits 15-8 of the first longword */ 387 tstb %a1@(TASK_THREAD+THREAD_FPSTATE+2) 388 jeq 3f 389#if !defined(CPU_M68060_ONLY) 390 jra 2f 391#endif 392#endif /* CONFIG_M68060 */ 393#if !defined(CPU_M68060_ONLY) 3941: tstb %a1@(TASK_THREAD+THREAD_FPSTATE) 395 jeq 3f 396#endif 3972: fmovemx %a1@(TASK_THREAD+THREAD_FPREG),%fp0-%fp7 398 fmoveml %a1@(TASK_THREAD+THREAD_FPCNTL),%fpcr/%fpsr/%fpiar 3993: frestore %a1@(TASK_THREAD+THREAD_FPSTATE) 4004: 401#endif /* CONFIG_M68KFPU_EMU_ONLY */ 402 403 /* restore the kernel stack pointer */ 404 movel %a1@(TASK_THREAD+THREAD_KSP),%sp 405 406 /* restore non-scratch registers */ 407 RESTORE_SWITCH_STACK 408 409 /* restore user stack pointer */ 410 movel %a1@(TASK_THREAD+THREAD_USP),%a0 411 movel %a0,%usp 412 413 /* restore fs (sfc,%dfc) */ 414 movew %a1@(TASK_THREAD+THREAD_FS),%a0 415 movec %a0,%sfc 416 movec %a0,%dfc 417 418 /* restore status register */ 419 movew %a1@(TASK_THREAD+THREAD_SR),%sr 420 421 rts 422 423#endif /* CONFIG_MMU && !CONFIG_COLDFIRE */ 424