1 /* SPDX-License-Identifier: GPL-2.0 */ !! 1 /* SPDX-License-Identifier: GPL-2.0-or-later
>> 2 * -*- mode: asm -*-
>> 3 *
>> 4 * linux/arch/m68k/kernel/entry.S
>> 5 *
>> 6 * Copyright (C) 1991, 1992 Linus Torvalds
>> 7 *
>> 8 * Linux/m68k support by Hamish Macdonald
>> 9 *
>> 10 * 68060 fixes by Jesper Skov
>> 11 *
>> 12 */
>> 13
2 /* 14 /*
3 * Copyright (C) 2020-2022 Loongson Technology !! 15 * entry.S contains the system-call and fault low-level handling routines.
>> 16 * This also contains the timer-interrupt handler, as well as all interrupts
>> 17 * and faults that can result in a task-switch.
4 * 18 *
5 * Derived from MIPS: !! 19 * NOTE: This code handles signal-recognition, which happens every time
6 * Copyright (C) 1994 - 2000, 2001, 2003 Ralf !! 20 * after a timer-interrupt and after each system call.
7 * Copyright (C) 1999, 2000 Silicon Graphics, !! 21 *
8 * Copyright (C) 2001 MIPS Technologies, Inc. !! 22 */
>> 23
>> 24 /*
>> 25 * 12/03/96 Jes: Currently we only support m68k single-cpu systems, so
>> 26 * all pointers that used to be 'current' are now entry
>> 27 * number 0 in the 'current_set' list.
>> 28 *
>> 29 * 6/05/00 RZ: addedd writeback completion after return from sighandler
>> 30 * for 68040
9 */ 31 */
10 32
11 #include <asm/asm.h> !! 33 #include <linux/linkage.h>
12 #include <asm/asmmacro.h> !! 34 #include <asm/errno.h>
13 #include <asm/loongarch.h> !! 35 #include <asm/setup.h>
14 #include <asm/regdef.h> !! 36 #include <asm/traps.h>
15 #include <asm/stackframe.h> !! 37 #include <asm/unistd.h>
16 #include <asm/thread_info.h> !! 38 #include <asm/asm-offsets.h>
17 #include <asm/unwind_hints.h> !! 39 #include <asm/entry.h>
18 !! 40
19 .text !! 41 .globl system_call, buserr, trap, resume
20 .cfi_sections .debug_frame !! 42 .globl sys_call_table
21 .align 5 !! 43 .globl __sys_fork, __sys_clone, __sys_vfork
22 SYM_CODE_START(handle_syscall) !! 44 .globl bad_interrupt
23 UNWIND_HINT_UNDEFINED !! 45 .globl auto_irqhandler_fixup
24 csrrd t0, PERCPU_BASE_KS !! 46 .globl user_irqvec_fixup
25 la.pcrel t1, kernelsp !! 47
26 add.d t1, t1, t0 !! 48 .text
27 move t2, sp !! 49 ENTRY(__sys_fork)
28 ld.d sp, t1, 0 !! 50 SAVE_SWITCH_STACK
29 !! 51 jbsr sys_fork
30 addi.d sp, sp, -PT_SIZE !! 52 lea %sp@(24),%sp
31 cfi_st t2, PT_R3 !! 53 rts
32 cfi_rel_offset sp, PT_R3 !! 54
33 st.d zero, sp, PT_R0 !! 55 ENTRY(__sys_clone)
34 csrrd t2, LOONGARCH_CSR_PRMD !! 56 SAVE_SWITCH_STACK
35 st.d t2, sp, PT_PRMD !! 57 pea %sp@(SWITCH_STACK_SIZE)
36 csrrd t2, LOONGARCH_CSR_CRMD !! 58 jbsr m68k_clone
37 st.d t2, sp, PT_CRMD !! 59 lea %sp@(28),%sp
38 csrrd t2, LOONGARCH_CSR_EUEN !! 60 rts
39 st.d t2, sp, PT_EUEN !! 61
40 csrrd t2, LOONGARCH_CSR_ECFG !! 62 ENTRY(__sys_vfork)
41 st.d t2, sp, PT_ECFG !! 63 SAVE_SWITCH_STACK
42 csrrd t2, LOONGARCH_CSR_ESTA !! 64 jbsr sys_vfork
43 st.d t2, sp, PT_ESTAT !! 65 lea %sp@(24),%sp
44 cfi_st ra, PT_R1 !! 66 rts
45 cfi_st a0, PT_R4 !! 67
46 cfi_st a1, PT_R5 !! 68 ENTRY(__sys_clone3)
47 cfi_st a2, PT_R6 !! 69 SAVE_SWITCH_STACK
48 cfi_st a3, PT_R7 !! 70 pea %sp@(SWITCH_STACK_SIZE)
49 cfi_st a4, PT_R8 !! 71 jbsr m68k_clone3
50 cfi_st a5, PT_R9 !! 72 lea %sp@(28),%sp
51 cfi_st a6, PT_R10 !! 73 rts
52 cfi_st a7, PT_R11 !! 74
53 csrrd ra, LOONGARCH_CSR_ERA !! 75 ENTRY(sys_sigreturn)
54 st.d ra, sp, PT_ERA !! 76 SAVE_SWITCH_STACK
55 cfi_rel_offset ra, PT_ERA !! 77 movel %sp,%a1 | switch_stack pointer
56 !! 78 lea %sp@(SWITCH_STACK_SIZE),%a0 | pt_regs pointer
57 cfi_st tp, PT_R2 !! 79 lea %sp@(-84),%sp | leave a gap
58 cfi_st u0, PT_R21 !! 80 movel %a1,%sp@-
59 cfi_st fp, PT_R22 !! 81 movel %a0,%sp@-
60 !! 82 jbsr do_sigreturn
61 SAVE_STATIC !! 83 jra 1f | shared with rt_sigreturn()
62 UNWIND_HINT_REGS !! 84
63 !! 85 ENTRY(sys_rt_sigreturn)
64 #ifdef CONFIG_KGDB !! 86 SAVE_SWITCH_STACK
65 li.w t1, CSR_CRMD_WE !! 87 movel %sp,%a1 | switch_stack pointer
66 csrxchg t1, t1, LOONGARCH_CSR_ !! 88 lea %sp@(SWITCH_STACK_SIZE),%a0 | pt_regs pointer
67 #endif !! 89 lea %sp@(-84),%sp | leave a gap
68 !! 90 movel %a1,%sp@-
69 move u0, t0 !! 91 movel %a0,%sp@-
70 li.d tp, ~_THREAD_MASK !! 92 | stack contents:
71 and tp, tp, sp !! 93 | [original pt_regs address] [original switch_stack address]
72 !! 94 | [gap] [switch_stack] [pt_regs] [exception frame]
73 move a0, sp !! 95 jbsr do_rt_sigreturn
74 bl do_syscall !! 96
75 !! 97 1:
76 RESTORE_ALL_AND_RET !! 98 | stack contents now:
77 SYM_CODE_END(handle_syscall) !! 99 | [original pt_regs address] [original switch_stack address]
78 _ASM_NOKPROBE(handle_syscall) !! 100 | [unused part of the gap] [moved switch_stack] [moved pt_regs]
79 !! 101 | [replacement exception frame]
80 SYM_CODE_START(ret_from_fork) !! 102 | return value of do_{rt_,}sigreturn() points to moved switch_stack.
81 UNWIND_HINT_REGS !! 103
82 bl schedule_tail !! 104 movel %d0,%sp | discard the leftover junk
83 move a0, sp !! 105 RESTORE_SWITCH_STACK
84 bl syscall_exit_to_user_m !! 106 | stack contents now is just [syscall return address] [pt_regs] [frame]
85 RESTORE_STATIC !! 107 | return pt_regs.d0
86 RESTORE_SOME !! 108 movel %sp@(PT_OFF_D0+4),%d0
87 RESTORE_SP_AND_RET !! 109 rts
88 SYM_CODE_END(ret_from_fork) !! 110
89 !! 111 ENTRY(buserr)
90 SYM_CODE_START(ret_from_kernel_thread) !! 112 SAVE_ALL_INT
91 UNWIND_HINT_REGS !! 113 GET_CURRENT(%d0)
92 bl schedule_tail !! 114 movel %sp,%sp@- | stack frame pointer argument
93 move a0, s1 !! 115 jbsr buserr_c
94 jirl ra, s0, 0 !! 116 addql #4,%sp
95 move a0, sp !! 117 jra ret_from_exception
96 bl syscall_exit_to_user_m !! 118
97 RESTORE_STATIC !! 119 ENTRY(trap)
98 RESTORE_SOME !! 120 SAVE_ALL_INT
99 RESTORE_SP_AND_RET !! 121 GET_CURRENT(%d0)
100 SYM_CODE_END(ret_from_kernel_thread) !! 122 movel %sp,%sp@- | stack frame pointer argument
>> 123 jbsr trap_c
>> 124 addql #4,%sp
>> 125 jra ret_from_exception
>> 126
>> 127 | After a fork we jump here directly from resume,
>> 128 | so that %d1 contains the previous task
>> 129 | schedule_tail now used regardless of CONFIG_SMP
>> 130 ENTRY(ret_from_fork)
>> 131 movel %d1,%sp@-
>> 132 jsr schedule_tail
>> 133 addql #4,%sp
>> 134 jra ret_from_exception
>> 135
>> 136 ENTRY(ret_from_kernel_thread)
>> 137 | a3 contains the kernel thread payload, d7 - its argument
>> 138 movel %d1,%sp@-
>> 139 jsr schedule_tail
>> 140 movel %d7,(%sp)
>> 141 jsr %a3@
>> 142 addql #4,%sp
>> 143 jra ret_from_exception
>> 144
>> 145 #if defined(CONFIG_COLDFIRE) || !defined(CONFIG_MMU)
>> 146
>> 147 #ifdef TRAP_DBG_INTERRUPT
>> 148
>> 149 .globl dbginterrupt
>> 150 ENTRY(dbginterrupt)
>> 151 SAVE_ALL_INT
>> 152 GET_CURRENT(%d0)
>> 153 movel %sp,%sp@- /* stack frame pointer argument */
>> 154 jsr dbginterrupt_c
>> 155 addql #4,%sp
>> 156 jra ret_from_exception
>> 157 #endif
>> 158
>> 159 ENTRY(reschedule)
>> 160 /* save top of frame */
>> 161 pea %sp@
>> 162 jbsr set_esp0
>> 163 addql #4,%sp
>> 164 pea ret_from_exception
>> 165 jmp schedule
>> 166
>> 167 ENTRY(ret_from_user_signal)
>> 168 moveq #__NR_sigreturn,%d0
>> 169 trap #0
>> 170
>> 171 ENTRY(ret_from_user_rt_signal)
>> 172 movel #__NR_rt_sigreturn,%d0
>> 173 trap #0
>> 174
>> 175 #else
>> 176
>> 177 do_trace_entry:
>> 178 movel #-ENOSYS,%sp@(PT_OFF_D0)| needed for strace
>> 179 subql #4,%sp
>> 180 SAVE_SWITCH_STACK
>> 181 jbsr syscall_trace_enter
>> 182 RESTORE_SWITCH_STACK
>> 183 addql #4,%sp
>> 184 addql #1,%d0 | optimization for cmpil #-1,%d0
>> 185 jeq ret_from_syscall
>> 186 movel %sp@(PT_OFF_ORIG_D0),%d0
>> 187 cmpl #NR_syscalls,%d0
>> 188 jcs syscall
>> 189 jra ret_from_syscall
>> 190 badsys:
>> 191 movel #-ENOSYS,%sp@(PT_OFF_D0)
>> 192 jra ret_from_syscall
>> 193
>> 194 do_trace_exit:
>> 195 subql #4,%sp
>> 196 SAVE_SWITCH_STACK
>> 197 jbsr syscall_trace_leave
>> 198 RESTORE_SWITCH_STACK
>> 199 addql #4,%sp
>> 200 jra .Lret_from_exception
>> 201
>> 202 ENTRY(system_call)
>> 203 SAVE_ALL_SYS
>> 204
>> 205 GET_CURRENT(%d1)
>> 206 movel %d1,%a1
>> 207
>> 208 | save top of frame
>> 209 movel %sp,%curptr@(TASK_THREAD+THREAD_ESP0)
>> 210
>> 211 | syscall trace?
>> 212 tstb %a1@(TINFO_FLAGS+2)
>> 213 jmi do_trace_entry
>> 214 | seccomp filter active?
>> 215 btst #5,%a1@(TINFO_FLAGS+2)
>> 216 bnes do_trace_entry
>> 217 cmpl #NR_syscalls,%d0
>> 218 jcc badsys
>> 219 syscall:
>> 220 jbsr @(sys_call_table,%d0:l:4)@(0)
>> 221 movel %d0,%sp@(PT_OFF_D0) | save the return value
>> 222 ret_from_syscall:
>> 223 |oriw #0x0700,%sr
>> 224 movel %curptr@(TASK_STACK),%a1
>> 225 movew %a1@(TINFO_FLAGS+2),%d0
>> 226 jne syscall_exit_work
>> 227 1: RESTORE_ALL
>> 228
>> 229 syscall_exit_work:
>> 230 btst #5,%sp@(PT_OFF_SR) | check if returning to kernel
>> 231 bnes 1b | if so, skip resched, signals
>> 232 lslw #1,%d0
>> 233 jcs do_trace_exit
>> 234 jmi do_delayed_trace
>> 235 lslw #8,%d0
>> 236 jne do_signal_return
>> 237 pea resume_userspace
>> 238 jra schedule
>> 239
>> 240
>> 241 ENTRY(ret_from_exception)
>> 242 .Lret_from_exception:
>> 243 btst #5,%sp@(PT_OFF_SR) | check if returning to kernel
>> 244 bnes 1f | if so, skip resched, signals
>> 245 | only allow interrupts when we are really the last one on the
>> 246 | kernel stack, otherwise stack overflow can occur during
>> 247 | heavy interrupt load
>> 248 andw #ALLOWINT,%sr
>> 249
>> 250 resume_userspace:
>> 251 movel %curptr@(TASK_STACK),%a1
>> 252 moveb %a1@(TINFO_FLAGS+3),%d0
>> 253 jne exit_work
>> 254 1: RESTORE_ALL
>> 255
>> 256 exit_work:
>> 257 | save top of frame
>> 258 movel %sp,%curptr@(TASK_THREAD+THREAD_ESP0)
>> 259 lslb #1,%d0
>> 260 jne do_signal_return
>> 261 pea resume_userspace
>> 262 jra schedule
>> 263
>> 264
>> 265 do_signal_return:
>> 266 |andw #ALLOWINT,%sr
>> 267 subql #4,%sp | dummy return address
>> 268 SAVE_SWITCH_STACK
>> 269 pea %sp@(SWITCH_STACK_SIZE)
>> 270 bsrl do_notify_resume
>> 271 addql #4,%sp
>> 272 RESTORE_SWITCH_STACK
>> 273 addql #4,%sp
>> 274 jbra resume_userspace
>> 275
>> 276 do_delayed_trace:
>> 277 bclr #7,%sp@(PT_OFF_SR) | clear trace bit in SR
>> 278 pea 1 | send SIGTRAP
>> 279 movel %curptr,%sp@-
>> 280 pea LSIGTRAP
>> 281 jbsr send_sig
>> 282 addql #8,%sp
>> 283 addql #4,%sp
>> 284 jbra resume_userspace
>> 285
>> 286
>> 287 /* This is the main interrupt handler for autovector interrupts */
>> 288
>> 289 ENTRY(auto_inthandler)
>> 290 SAVE_ALL_INT
>> 291 GET_CURRENT(%d0)
>> 292 | put exception # in d0
>> 293 bfextu %sp@(PT_OFF_FORMATVEC){#4,#10},%d0
>> 294 subw #VEC_SPUR,%d0
>> 295
>> 296 movel %sp,%sp@-
>> 297 movel %d0,%sp@- | put vector # on stack
>> 298 auto_irqhandler_fixup = . + 2
>> 299 jsr do_IRQ | process the IRQ
>> 300 addql #8,%sp | pop parameters off stack
>> 301 jra ret_from_exception
>> 302
>> 303 /* Handler for user defined interrupt vectors */
>> 304
>> 305 ENTRY(user_inthandler)
>> 306 SAVE_ALL_INT
>> 307 GET_CURRENT(%d0)
>> 308 | put exception # in d0
>> 309 bfextu %sp@(PT_OFF_FORMATVEC){#4,#10},%d0
>> 310 user_irqvec_fixup = . + 2
>> 311 subw #VEC_USER,%d0
>> 312
>> 313 movel %sp,%sp@-
>> 314 movel %d0,%sp@- | put vector # on stack
>> 315 jsr do_IRQ | process the IRQ
>> 316 addql #8,%sp | pop parameters off stack
>> 317 jra ret_from_exception
>> 318
>> 319 /* Handler for uninitialized and spurious interrupts */
>> 320
>> 321 ENTRY(bad_inthandler)
>> 322 SAVE_ALL_INT
>> 323 GET_CURRENT(%d0)
>> 324
>> 325 movel %sp,%sp@-
>> 326 jsr handle_badint
>> 327 addql #4,%sp
>> 328 jra ret_from_exception
>> 329
>> 330 resume:
>> 331 /*
>> 332 * Beware - when entering resume, prev (the current task) is
>> 333 * in a0, next (the new task) is in a1,so don't change these
>> 334 * registers until their contents are no longer needed.
>> 335 */
>> 336
>> 337 /* save sr */
>> 338 movew %sr,%a0@(TASK_THREAD+THREAD_SR)
>> 339
>> 340 /* save fs (sfc,%dfc) (may be pointing to kernel memory) */
>> 341 movec %sfc,%d0
>> 342 movew %d0,%a0@(TASK_THREAD+THREAD_FC)
>> 343
>> 344 /* save usp */
>> 345 /* it is better to use a movel here instead of a movew 8*) */
>> 346 movec %usp,%d0
>> 347 movel %d0,%a0@(TASK_THREAD+THREAD_USP)
>> 348
>> 349 /* save non-scratch registers on stack */
>> 350 SAVE_SWITCH_STACK
>> 351
>> 352 /* save current kernel stack pointer */
>> 353 movel %sp,%a0@(TASK_THREAD+THREAD_KSP)
>> 354
>> 355 /* save floating point context */
>> 356 #ifndef CONFIG_M68KFPU_EMU_ONLY
>> 357 #ifdef CONFIG_M68KFPU_EMU
>> 358 tstl m68k_fputype
>> 359 jeq 3f
>> 360 #endif
>> 361 fsave %a0@(TASK_THREAD+THREAD_FPSTATE)
>> 362
>> 363 #if defined(CONFIG_M68060)
>> 364 #if !defined(CPU_M68060_ONLY)
>> 365 btst #3,m68k_cputype+3
>> 366 beqs 1f
>> 367 #endif
>> 368 /* The 060 FPU keeps status in bits 15-8 of the first longword */
>> 369 tstb %a0@(TASK_THREAD+THREAD_FPSTATE+2)
>> 370 jeq 3f
>> 371 #if !defined(CPU_M68060_ONLY)
>> 372 jra 2f
>> 373 #endif
>> 374 #endif /* CONFIG_M68060 */
>> 375 #if !defined(CPU_M68060_ONLY)
>> 376 1: tstb %a0@(TASK_THREAD+THREAD_FPSTATE)
>> 377 jeq 3f
>> 378 #endif
>> 379 2: fmovemx %fp0-%fp7,%a0@(TASK_THREAD+THREAD_FPREG)
>> 380 fmoveml %fpcr/%fpsr/%fpiar,%a0@(TASK_THREAD+THREAD_FPCNTL)
>> 381 3:
>> 382 #endif /* CONFIG_M68KFPU_EMU_ONLY */
>> 383 /* Return previous task in %d1 */
>> 384 movel %curptr,%d1
>> 385
>> 386 /* switch to new task (a1 contains new task) */
>> 387 movel %a1,%curptr
>> 388
>> 389 /* restore floating point context */
>> 390 #ifndef CONFIG_M68KFPU_EMU_ONLY
>> 391 #ifdef CONFIG_M68KFPU_EMU
>> 392 tstl m68k_fputype
>> 393 jeq 4f
>> 394 #endif
>> 395 #if defined(CONFIG_M68060)
>> 396 #if !defined(CPU_M68060_ONLY)
>> 397 btst #3,m68k_cputype+3
>> 398 beqs 1f
>> 399 #endif
>> 400 /* The 060 FPU keeps status in bits 15-8 of the first longword */
>> 401 tstb %a1@(TASK_THREAD+THREAD_FPSTATE+2)
>> 402 jeq 3f
>> 403 #if !defined(CPU_M68060_ONLY)
>> 404 jra 2f
>> 405 #endif
>> 406 #endif /* CONFIG_M68060 */
>> 407 #if !defined(CPU_M68060_ONLY)
>> 408 1: tstb %a1@(TASK_THREAD+THREAD_FPSTATE)
>> 409 jeq 3f
>> 410 #endif
>> 411 2: fmovemx %a1@(TASK_THREAD+THREAD_FPREG),%fp0-%fp7
>> 412 fmoveml %a1@(TASK_THREAD+THREAD_FPCNTL),%fpcr/%fpsr/%fpiar
>> 413 3: frestore %a1@(TASK_THREAD+THREAD_FPSTATE)
>> 414 4:
>> 415 #endif /* CONFIG_M68KFPU_EMU_ONLY */
>> 416
>> 417 /* restore the kernel stack pointer */
>> 418 movel %a1@(TASK_THREAD+THREAD_KSP),%sp
>> 419
>> 420 /* restore non-scratch registers */
>> 421 RESTORE_SWITCH_STACK
>> 422
>> 423 /* restore user stack pointer */
>> 424 movel %a1@(TASK_THREAD+THREAD_USP),%a0
>> 425 movel %a0,%usp
>> 426
>> 427 /* restore fs (sfc,%dfc) */
>> 428 movew %a1@(TASK_THREAD+THREAD_FC),%a0
>> 429 movec %a0,%sfc
>> 430 movec %a0,%dfc
>> 431
>> 432 /* restore status register */
>> 433 movew %a1@(TASK_THREAD+THREAD_SR),%d0
>> 434 oriw #0x0700,%d0
>> 435 movew %d0,%sr
>> 436
>> 437 rts
>> 438
>> 439 #endif /* CONFIG_MMU && !CONFIG_COLDFIRE */
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