1 /* SPDX-License-Identifier: GPL-2.0-only */ !! 1 /* SPDX-License-Identifier: GPL-2.0 */
2 /* 2 /*
3 * Common Low Level Interrupts/Traps/Exception !! 3 * arch/alpha/kernel/entry.S
4 * (included from entry-<isa>.S <<
5 * 4 *
6 * Copyright (C) 2014-15 Synopsys, Inc. (www.s !! 5 * Kernel entry-points.
7 * Copyright (C) 2004, 2007-2010, 2011-2012 Sy <<
8 */ 6 */
9 7
10 /*-------------------------------------------- !! 8 #include <asm/asm-offsets.h>
11 * Function ABI !! 9 #include <asm/thread_info.h>
12 *-------------------------------------------- !! 10 #include <asm/pal.h>
13 * !! 11 #include <asm/errno.h>
14 * Arguments r0 - r !! 12 #include <asm/unistd.h>
15 * Caller Saved Registers r0 - r !! 13
16 * Callee Saved Registers r13- r !! 14 .text
17 * Global Pointer (gp) r26 !! 15 .set noat
18 * Frame Pointer (fp) r27 !! 16 .cfi_sections .debug_frame
19 * Stack Pointer (sp) r28 !! 17
20 * Branch link register (blink) r31 !! 18 /* Stack offsets. */
21 *-------------------------------------------- !! 19 #define SP_OFF 184
22 */ !! 20 #define SWITCH_STACK_SIZE 64
23 !! 21
24 ;################### Special Sys Call Wrappers !! 22 .macro CFI_START_OSF_FRAME func
25 !! 23 .align 4
26 ENTRY(sys_clone_wrapper) !! 24 .globl \func
27 SAVE_CALLEE_SAVED_USER !! 25 .type \func,@function
28 bl @sys_clone !! 26 \func:
29 DISCARD_CALLEE_SAVED_USER !! 27 .cfi_startproc simple
30 !! 28 .cfi_return_column 64
31 GET_CURR_THR_INFO_FLAGS r10 !! 29 .cfi_def_cfa $sp, 48
32 and.f 0, r10, _TIF_SYSCALL_WORK !! 30 .cfi_rel_offset 64, 8
33 bnz tracesys_exit !! 31 .cfi_rel_offset $gp, 16
34 !! 32 .cfi_rel_offset $16, 24
35 b .Lret_from_system_call !! 33 .cfi_rel_offset $17, 32
36 END(sys_clone_wrapper) !! 34 .cfi_rel_offset $18, 40
37 !! 35 .endm
38 ENTRY(sys_clone3_wrapper) !! 36
39 SAVE_CALLEE_SAVED_USER !! 37 .macro CFI_END_OSF_FRAME func
40 bl @sys_clone3 !! 38 .cfi_endproc
41 DISCARD_CALLEE_SAVED_USER !! 39 .size \func, . - \func
42 !! 40 .endm
43 GET_CURR_THR_INFO_FLAGS r10 <<
44 and.f 0, r10, _TIF_SYSCALL_WORK <<
45 bnz tracesys_exit <<
46 <<
47 b .Lret_from_system_call <<
48 END(sys_clone3_wrapper) <<
49 <<
50 ENTRY(ret_from_fork) <<
51 ; when the forked child comes here fro <<
52 ; r0 has the last task pointer. <<
53 ; put last task in scheduler queue <<
54 jl @schedule_tail <<
55 <<
56 ld r9, [sp, PT_status32] <<
57 brne r9, 0, 1f <<
58 <<
59 jl.d [r14] ; kernel threa <<
60 mov r0, r13 ; (see PF_KTHR <<
61 <<
62 1: <<
63 ; Return to user space <<
64 ; 1. Any forked task (Reach here via B <<
65 ; 2. First ever init task (Reach here <<
66 ; This is the historic "kernel_exec <<
67 ; user mode, in a round about way s <<
68 ; a kernel thread which is executed <<
69 ; out whenever kernel_execve (now i <<
70 b ret_from_exception <<
71 END(ret_from_fork) <<
72 <<
73 ;################### Non TLB Exception Handlin <<
74 41
75 ; -------------------------------------------- !! 42 /*
76 ; Instruction Error Exception Handler !! 43 * This defines the normal kernel pt-regs layout.
77 ; -------------------------------------------- !! 44 *
78 !! 45 * regs 9-15 preserved by C code
79 ENTRY(instr_service) !! 46 * regs 16-18 saved by PAL-code
80 !! 47 * regs 29-30 saved and set up by PAL-code
81 EXCEPTION_PROLOGUE !! 48 * JRP - Save regs 16-18 in a special area of the stack, so that
82 !! 49 * the palcode-provided values are available to the signal handler.
83 bl do_insterror_or_kprobe !! 50 */
84 b ret_from_exception <<
85 END(instr_service) <<
86 51
87 ; -------------------------------------------- !! 52 .macro SAVE_ALL
88 ; Machine Check Exception Handler !! 53 subq $sp, SP_OFF, $sp
89 ; -------------------------------------------- !! 54 .cfi_adjust_cfa_offset SP_OFF
>> 55 stq $0, 0($sp)
>> 56 stq $1, 8($sp)
>> 57 stq $2, 16($sp)
>> 58 stq $3, 24($sp)
>> 59 stq $4, 32($sp)
>> 60 stq $28, 144($sp)
>> 61 .cfi_rel_offset $0, 0
>> 62 .cfi_rel_offset $1, 8
>> 63 .cfi_rel_offset $2, 16
>> 64 .cfi_rel_offset $3, 24
>> 65 .cfi_rel_offset $4, 32
>> 66 .cfi_rel_offset $28, 144
>> 67 lda $2, alpha_mv
>> 68 stq $5, 40($sp)
>> 69 stq $6, 48($sp)
>> 70 stq $7, 56($sp)
>> 71 stq $8, 64($sp)
>> 72 stq $19, 72($sp)
>> 73 stq $20, 80($sp)
>> 74 stq $21, 88($sp)
>> 75 ldq $2, HAE_CACHE($2)
>> 76 stq $22, 96($sp)
>> 77 stq $23, 104($sp)
>> 78 stq $24, 112($sp)
>> 79 stq $25, 120($sp)
>> 80 stq $26, 128($sp)
>> 81 stq $27, 136($sp)
>> 82 stq $2, 152($sp)
>> 83 stq $16, 160($sp)
>> 84 stq $17, 168($sp)
>> 85 stq $18, 176($sp)
>> 86 .cfi_rel_offset $5, 40
>> 87 .cfi_rel_offset $6, 48
>> 88 .cfi_rel_offset $7, 56
>> 89 .cfi_rel_offset $8, 64
>> 90 .cfi_rel_offset $19, 72
>> 91 .cfi_rel_offset $20, 80
>> 92 .cfi_rel_offset $21, 88
>> 93 .cfi_rel_offset $22, 96
>> 94 .cfi_rel_offset $23, 104
>> 95 .cfi_rel_offset $24, 112
>> 96 .cfi_rel_offset $25, 120
>> 97 .cfi_rel_offset $26, 128
>> 98 .cfi_rel_offset $27, 136
>> 99 .endm
>> 100
>> 101 .macro RESTORE_ALL
>> 102 lda $19, alpha_mv
>> 103 ldq $0, 0($sp)
>> 104 ldq $1, 8($sp)
>> 105 ldq $2, 16($sp)
>> 106 ldq $3, 24($sp)
>> 107 ldq $21, 152($sp)
>> 108 ldq $20, HAE_CACHE($19)
>> 109 ldq $4, 32($sp)
>> 110 ldq $5, 40($sp)
>> 111 ldq $6, 48($sp)
>> 112 ldq $7, 56($sp)
>> 113 subq $20, $21, $20
>> 114 ldq $8, 64($sp)
>> 115 beq $20, 99f
>> 116 ldq $20, HAE_REG($19)
>> 117 stq $21, HAE_CACHE($19)
>> 118 stq $21, 0($20)
>> 119 99: ldq $19, 72($sp)
>> 120 ldq $20, 80($sp)
>> 121 ldq $21, 88($sp)
>> 122 ldq $22, 96($sp)
>> 123 ldq $23, 104($sp)
>> 124 ldq $24, 112($sp)
>> 125 ldq $25, 120($sp)
>> 126 ldq $26, 128($sp)
>> 127 ldq $27, 136($sp)
>> 128 ldq $28, 144($sp)
>> 129 addq $sp, SP_OFF, $sp
>> 130 .cfi_restore $0
>> 131 .cfi_restore $1
>> 132 .cfi_restore $2
>> 133 .cfi_restore $3
>> 134 .cfi_restore $4
>> 135 .cfi_restore $5
>> 136 .cfi_restore $6
>> 137 .cfi_restore $7
>> 138 .cfi_restore $8
>> 139 .cfi_restore $19
>> 140 .cfi_restore $20
>> 141 .cfi_restore $21
>> 142 .cfi_restore $22
>> 143 .cfi_restore $23
>> 144 .cfi_restore $24
>> 145 .cfi_restore $25
>> 146 .cfi_restore $26
>> 147 .cfi_restore $27
>> 148 .cfi_restore $28
>> 149 .cfi_adjust_cfa_offset -SP_OFF
>> 150 .endm
>> 151
>> 152 .macro DO_SWITCH_STACK
>> 153 bsr $1, do_switch_stack
>> 154 .cfi_adjust_cfa_offset SWITCH_STACK_SIZE
>> 155 .cfi_rel_offset $9, 0
>> 156 .cfi_rel_offset $10, 8
>> 157 .cfi_rel_offset $11, 16
>> 158 .cfi_rel_offset $12, 24
>> 159 .cfi_rel_offset $13, 32
>> 160 .cfi_rel_offset $14, 40
>> 161 .cfi_rel_offset $15, 48
>> 162 .endm
>> 163
>> 164 .macro UNDO_SWITCH_STACK
>> 165 bsr $1, undo_switch_stack
>> 166 .cfi_restore $9
>> 167 .cfi_restore $10
>> 168 .cfi_restore $11
>> 169 .cfi_restore $12
>> 170 .cfi_restore $13
>> 171 .cfi_restore $14
>> 172 .cfi_restore $15
>> 173 .cfi_adjust_cfa_offset -SWITCH_STACK_SIZE
>> 174 .endm
90 175
91 ENTRY(EV_MachineCheck) !! 176 /*
>> 177 * Non-syscall kernel entry points.
>> 178 */
92 179
93 EXCEPTION_PROLOGUE_KEEP_AE ; ECR !! 180 CFI_START_OSF_FRAME entInt
>> 181 SAVE_ALL
>> 182 lda $8, 0x3fff
>> 183 lda $26, ret_from_sys_call
>> 184 bic $sp, $8, $8
>> 185 mov $sp, $19
>> 186 jsr $31, do_entInt
>> 187 CFI_END_OSF_FRAME entInt
>> 188
>> 189 CFI_START_OSF_FRAME entArith
>> 190 SAVE_ALL
>> 191 lda $8, 0x3fff
>> 192 lda $26, ret_from_sys_call
>> 193 bic $sp, $8, $8
>> 194 mov $sp, $18
>> 195 jsr $31, do_entArith
>> 196 CFI_END_OSF_FRAME entArith
>> 197
>> 198 CFI_START_OSF_FRAME entMM
>> 199 SAVE_ALL
>> 200 /* save $9 - $15 so the inline exception code can manipulate them. */
>> 201 subq $sp, 56, $sp
>> 202 .cfi_adjust_cfa_offset 56
>> 203 stq $9, 0($sp)
>> 204 stq $10, 8($sp)
>> 205 stq $11, 16($sp)
>> 206 stq $12, 24($sp)
>> 207 stq $13, 32($sp)
>> 208 stq $14, 40($sp)
>> 209 stq $15, 48($sp)
>> 210 .cfi_rel_offset $9, 0
>> 211 .cfi_rel_offset $10, 8
>> 212 .cfi_rel_offset $11, 16
>> 213 .cfi_rel_offset $12, 24
>> 214 .cfi_rel_offset $13, 32
>> 215 .cfi_rel_offset $14, 40
>> 216 .cfi_rel_offset $15, 48
>> 217 addq $sp, 56, $19
>> 218 /* handle the fault */
>> 219 lda $8, 0x3fff
>> 220 bic $sp, $8, $8
>> 221 jsr $26, do_page_fault
>> 222 /* reload the registers after the exception code played. */
>> 223 ldq $9, 0($sp)
>> 224 ldq $10, 8($sp)
>> 225 ldq $11, 16($sp)
>> 226 ldq $12, 24($sp)
>> 227 ldq $13, 32($sp)
>> 228 ldq $14, 40($sp)
>> 229 ldq $15, 48($sp)
>> 230 addq $sp, 56, $sp
>> 231 .cfi_restore $9
>> 232 .cfi_restore $10
>> 233 .cfi_restore $11
>> 234 .cfi_restore $12
>> 235 .cfi_restore $13
>> 236 .cfi_restore $14
>> 237 .cfi_restore $15
>> 238 .cfi_adjust_cfa_offset -56
>> 239 /* finish up the syscall as normal. */
>> 240 br ret_from_sys_call
>> 241 CFI_END_OSF_FRAME entMM
>> 242
>> 243 CFI_START_OSF_FRAME entIF
>> 244 SAVE_ALL
>> 245 lda $8, 0x3fff
>> 246 lda $26, ret_from_sys_call
>> 247 bic $sp, $8, $8
>> 248 mov $sp, $17
>> 249 jsr $31, do_entIF
>> 250 CFI_END_OSF_FRAME entIF
>> 251
>> 252 CFI_START_OSF_FRAME entUna
>> 253 lda $sp, -256($sp)
>> 254 .cfi_adjust_cfa_offset 256
>> 255 stq $0, 0($sp)
>> 256 .cfi_rel_offset $0, 0
>> 257 .cfi_remember_state
>> 258 ldq $0, 256($sp) /* get PS */
>> 259 stq $1, 8($sp)
>> 260 stq $2, 16($sp)
>> 261 stq $3, 24($sp)
>> 262 and $0, 8, $0 /* user mode? */
>> 263 stq $4, 32($sp)
>> 264 bne $0, entUnaUser /* yup -> do user-level unaligned fault */
>> 265 stq $5, 40($sp)
>> 266 stq $6, 48($sp)
>> 267 stq $7, 56($sp)
>> 268 stq $8, 64($sp)
>> 269 stq $9, 72($sp)
>> 270 stq $10, 80($sp)
>> 271 stq $11, 88($sp)
>> 272 stq $12, 96($sp)
>> 273 stq $13, 104($sp)
>> 274 stq $14, 112($sp)
>> 275 stq $15, 120($sp)
>> 276 /* 16-18 PAL-saved */
>> 277 stq $19, 152($sp)
>> 278 stq $20, 160($sp)
>> 279 stq $21, 168($sp)
>> 280 stq $22, 176($sp)
>> 281 stq $23, 184($sp)
>> 282 stq $24, 192($sp)
>> 283 stq $25, 200($sp)
>> 284 stq $26, 208($sp)
>> 285 stq $27, 216($sp)
>> 286 stq $28, 224($sp)
>> 287 mov $sp, $19
>> 288 stq $gp, 232($sp)
>> 289 .cfi_rel_offset $1, 1*8
>> 290 .cfi_rel_offset $2, 2*8
>> 291 .cfi_rel_offset $3, 3*8
>> 292 .cfi_rel_offset $4, 4*8
>> 293 .cfi_rel_offset $5, 5*8
>> 294 .cfi_rel_offset $6, 6*8
>> 295 .cfi_rel_offset $7, 7*8
>> 296 .cfi_rel_offset $8, 8*8
>> 297 .cfi_rel_offset $9, 9*8
>> 298 .cfi_rel_offset $10, 10*8
>> 299 .cfi_rel_offset $11, 11*8
>> 300 .cfi_rel_offset $12, 12*8
>> 301 .cfi_rel_offset $13, 13*8
>> 302 .cfi_rel_offset $14, 14*8
>> 303 .cfi_rel_offset $15, 15*8
>> 304 .cfi_rel_offset $19, 19*8
>> 305 .cfi_rel_offset $20, 20*8
>> 306 .cfi_rel_offset $21, 21*8
>> 307 .cfi_rel_offset $22, 22*8
>> 308 .cfi_rel_offset $23, 23*8
>> 309 .cfi_rel_offset $24, 24*8
>> 310 .cfi_rel_offset $25, 25*8
>> 311 .cfi_rel_offset $26, 26*8
>> 312 .cfi_rel_offset $27, 27*8
>> 313 .cfi_rel_offset $28, 28*8
>> 314 .cfi_rel_offset $29, 29*8
>> 315 lda $8, 0x3fff
>> 316 stq $31, 248($sp)
>> 317 bic $sp, $8, $8
>> 318 jsr $26, do_entUna
>> 319 ldq $0, 0($sp)
>> 320 ldq $1, 8($sp)
>> 321 ldq $2, 16($sp)
>> 322 ldq $3, 24($sp)
>> 323 ldq $4, 32($sp)
>> 324 ldq $5, 40($sp)
>> 325 ldq $6, 48($sp)
>> 326 ldq $7, 56($sp)
>> 327 ldq $8, 64($sp)
>> 328 ldq $9, 72($sp)
>> 329 ldq $10, 80($sp)
>> 330 ldq $11, 88($sp)
>> 331 ldq $12, 96($sp)
>> 332 ldq $13, 104($sp)
>> 333 ldq $14, 112($sp)
>> 334 ldq $15, 120($sp)
>> 335 /* 16-18 PAL-saved */
>> 336 ldq $19, 152($sp)
>> 337 ldq $20, 160($sp)
>> 338 ldq $21, 168($sp)
>> 339 ldq $22, 176($sp)
>> 340 ldq $23, 184($sp)
>> 341 ldq $24, 192($sp)
>> 342 ldq $25, 200($sp)
>> 343 ldq $26, 208($sp)
>> 344 ldq $27, 216($sp)
>> 345 ldq $28, 224($sp)
>> 346 ldq $gp, 232($sp)
>> 347 lda $sp, 256($sp)
>> 348 .cfi_restore $1
>> 349 .cfi_restore $2
>> 350 .cfi_restore $3
>> 351 .cfi_restore $4
>> 352 .cfi_restore $5
>> 353 .cfi_restore $6
>> 354 .cfi_restore $7
>> 355 .cfi_restore $8
>> 356 .cfi_restore $9
>> 357 .cfi_restore $10
>> 358 .cfi_restore $11
>> 359 .cfi_restore $12
>> 360 .cfi_restore $13
>> 361 .cfi_restore $14
>> 362 .cfi_restore $15
>> 363 .cfi_restore $19
>> 364 .cfi_restore $20
>> 365 .cfi_restore $21
>> 366 .cfi_restore $22
>> 367 .cfi_restore $23
>> 368 .cfi_restore $24
>> 369 .cfi_restore $25
>> 370 .cfi_restore $26
>> 371 .cfi_restore $27
>> 372 .cfi_restore $28
>> 373 .cfi_restore $29
>> 374 .cfi_adjust_cfa_offset -256
>> 375 call_pal PAL_rti
>> 376
>> 377 .align 4
>> 378 entUnaUser:
>> 379 .cfi_restore_state
>> 380 ldq $0, 0($sp) /* restore original $0 */
>> 381 lda $sp, 256($sp) /* pop entUna's stack frame */
>> 382 .cfi_restore $0
>> 383 .cfi_adjust_cfa_offset -256
>> 384 SAVE_ALL /* setup normal kernel stack */
>> 385 lda $sp, -56($sp)
>> 386 .cfi_adjust_cfa_offset 56
>> 387 stq $9, 0($sp)
>> 388 stq $10, 8($sp)
>> 389 stq $11, 16($sp)
>> 390 stq $12, 24($sp)
>> 391 stq $13, 32($sp)
>> 392 stq $14, 40($sp)
>> 393 stq $15, 48($sp)
>> 394 .cfi_rel_offset $9, 0
>> 395 .cfi_rel_offset $10, 8
>> 396 .cfi_rel_offset $11, 16
>> 397 .cfi_rel_offset $12, 24
>> 398 .cfi_rel_offset $13, 32
>> 399 .cfi_rel_offset $14, 40
>> 400 .cfi_rel_offset $15, 48
>> 401 lda $8, 0x3fff
>> 402 addq $sp, 56, $19
>> 403 bic $sp, $8, $8
>> 404 jsr $26, do_entUnaUser
>> 405 ldq $9, 0($sp)
>> 406 ldq $10, 8($sp)
>> 407 ldq $11, 16($sp)
>> 408 ldq $12, 24($sp)
>> 409 ldq $13, 32($sp)
>> 410 ldq $14, 40($sp)
>> 411 ldq $15, 48($sp)
>> 412 lda $sp, 56($sp)
>> 413 .cfi_restore $9
>> 414 .cfi_restore $10
>> 415 .cfi_restore $11
>> 416 .cfi_restore $12
>> 417 .cfi_restore $13
>> 418 .cfi_restore $14
>> 419 .cfi_restore $15
>> 420 .cfi_adjust_cfa_offset -56
>> 421 br ret_from_sys_call
>> 422 CFI_END_OSF_FRAME entUna
>> 423
>> 424 CFI_START_OSF_FRAME entDbg
>> 425 SAVE_ALL
>> 426 lda $8, 0x3fff
>> 427 lda $26, ret_from_sys_call
>> 428 bic $sp, $8, $8
>> 429 mov $sp, $16
>> 430 jsr $31, do_entDbg
>> 431 CFI_END_OSF_FRAME entDbg
>> 432
>> 433 /*
>> 434 * The system call entry point is special. Most importantly, it looks
>> 435 * like a function call to userspace as far as clobbered registers. We
>> 436 * do preserve the argument registers (for syscall restarts) and $26
>> 437 * (for leaf syscall functions).
>> 438 *
>> 439 * So much for theory. We don't take advantage of this yet.
>> 440 *
>> 441 * Note that a0-a2 are not saved by PALcode as with the other entry points.
>> 442 */
94 443
95 lr r0, [efa] !! 444 .align 4
96 mov r1, sp !! 445 .globl entSys
>> 446 .type entSys, @function
>> 447 .cfi_startproc simple
>> 448 .cfi_return_column 64
>> 449 .cfi_def_cfa $sp, 48
>> 450 .cfi_rel_offset 64, 8
>> 451 .cfi_rel_offset $gp, 16
>> 452 entSys:
>> 453 SAVE_ALL
>> 454 lda $8, 0x3fff
>> 455 bic $sp, $8, $8
>> 456 lda $4, NR_syscalls($31)
>> 457 stq $16, SP_OFF+24($sp)
>> 458 lda $5, sys_call_table
>> 459 lda $27, sys_ni_syscall
>> 460 cmpult $0, $4, $4
>> 461 ldl $3, TI_FLAGS($8)
>> 462 stq $17, SP_OFF+32($sp)
>> 463 s8addq $0, $5, $5
>> 464 stq $18, SP_OFF+40($sp)
>> 465 .cfi_rel_offset $16, SP_OFF+24
>> 466 .cfi_rel_offset $17, SP_OFF+32
>> 467 .cfi_rel_offset $18, SP_OFF+40
>> 468 #ifdef CONFIG_AUDITSYSCALL
>> 469 lda $6, _TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT
>> 470 and $3, $6, $3
>> 471 bne $3, strace
>> 472 #else
>> 473 blbs $3, strace /* check for SYSCALL_TRACE in disguise */
>> 474 #endif
>> 475 beq $4, 1f
>> 476 ldq $27, 0($5)
>> 477 1: jsr $26, ($27), sys_ni_syscall
>> 478 ldgp $gp, 0($26)
>> 479 blt $0, $syscall_error /* the call failed */
>> 480 $ret_success:
>> 481 stq $0, 0($sp)
>> 482 stq $31, 72($sp) /* a3=0 => no error */
>> 483
>> 484 .align 4
>> 485 .globl ret_from_sys_call
>> 486 ret_from_sys_call:
>> 487 cmovne $26, 0, $18 /* $18 = 0 => non-restartable */
>> 488 ldq $0, SP_OFF($sp)
>> 489 and $0, 8, $0
>> 490 beq $0, ret_to_kernel
>> 491 ret_to_user:
>> 492 /* Make sure need_resched and sigpending don't change between
>> 493 sampling and the rti. */
>> 494 lda $16, 7
>> 495 call_pal PAL_swpipl
>> 496 ldl $17, TI_FLAGS($8)
>> 497 and $17, _TIF_WORK_MASK, $2
>> 498 bne $2, work_pending
>> 499 restore_all:
>> 500 ldl $2, TI_STATUS($8)
>> 501 and $2, TS_SAVED_FP | TS_RESTORE_FP, $3
>> 502 bne $3, restore_fpu
>> 503 restore_other:
>> 504 .cfi_remember_state
>> 505 RESTORE_ALL
>> 506 call_pal PAL_rti
>> 507
>> 508 ret_to_kernel:
>> 509 .cfi_restore_state
>> 510 lda $16, 7
>> 511 call_pal PAL_swpipl
>> 512 br restore_other
>> 513
>> 514 .align 3
>> 515 $syscall_error:
>> 516 /*
>> 517 * Some system calls (e.g., ptrace) can return arbitrary
>> 518 * values which might normally be mistaken as error numbers.
>> 519 * Those functions must zero $0 (v0) directly in the stack
>> 520 * frame to indicate that a negative return value wasn't an
>> 521 * error number..
>> 522 */
>> 523 ldq $18, 0($sp) /* old syscall nr (zero if success) */
>> 524 beq $18, $ret_success
>> 525
>> 526 ldq $19, 72($sp) /* .. and this a3 */
>> 527 subq $31, $0, $0 /* with error in v0 */
>> 528 addq $31, 1, $1 /* set a3 for errno return */
>> 529 stq $0, 0($sp)
>> 530 mov $31, $26 /* tell "ret_from_sys_call" we can restart */
>> 531 stq $1, 72($sp) /* a3 for return */
>> 532 br ret_from_sys_call
97 533
98 ; MC exceptions disable MMU !! 534 /*
99 ARC_MMU_REENABLE r3 !! 535 * Do all cleanup when returning from all interrupts and system calls.
>> 536 *
>> 537 * Arguments:
>> 538 * $8: current.
>> 539 * $17: TI_FLAGS.
>> 540 * $18: The old syscall number, or zero if this is not a return
>> 541 * from a syscall that errored and is possibly restartable.
>> 542 * $19: The old a3 value
>> 543 */
100 544
101 lsr r3, r10, 8 !! 545 .align 4
102 bmsk r3, r3, 7 !! 546 .type work_pending, @function
103 brne r3, ECR_C_MCHK_DUP_TLB, 1f !! 547 work_pending:
>> 548 and $17, _TIF_NOTIFY_RESUME | _TIF_SIGPENDING | _TIF_NOTIFY_SIGNAL, $2
>> 549 bne $2, $work_notifysig
>> 550
>> 551 $work_resched:
>> 552 /*
>> 553 * We can get here only if we returned from syscall without SIGPENDING
>> 554 * or got through work_notifysig already. Either case means no syscall
>> 555 * restarts for us, so let $18 and $19 burn.
>> 556 */
>> 557 jsr $26, schedule
>> 558 mov 0, $18
>> 559 br ret_to_user
>> 560
>> 561 $work_notifysig:
>> 562 mov $sp, $16
>> 563 DO_SWITCH_STACK
>> 564 jsr $26, do_work_pending
>> 565 UNDO_SWITCH_STACK
>> 566 br restore_all
104 567
105 bl do_tlb_overlap_fault !! 568 /*
106 b ret_from_exception !! 569 * PTRACE syscall handler
>> 570 */
107 571
>> 572 .align 4
>> 573 .type strace, @function
>> 574 strace:
>> 575 /* set up signal stack, call syscall_trace */
>> 576 // NB: if anyone adds preemption, this block will need to be protected
>> 577 ldl $1, TI_STATUS($8)
>> 578 and $1, TS_SAVED_FP, $3
>> 579 or $1, TS_SAVED_FP, $2
>> 580 bne $3, 1f
>> 581 stl $2, TI_STATUS($8)
>> 582 bsr $26, __save_fpu
108 1: 583 1:
109 ; DEAD END: can't do much, display Reg !! 584 DO_SWITCH_STACK
110 SAVE_CALLEE_SAVED_USER !! 585 jsr $26, syscall_trace_enter /* returns the syscall number */
111 !! 586 UNDO_SWITCH_STACK
112 GET_CURR_TASK_FIELD_PTR TASK_THREAD, !! 587
113 st sp, [r10, THREAD_CALLEE_REG] !! 588 /* get the arguments back.. */
114 !! 589 ldq $16, SP_OFF+24($sp)
115 j do_machine_check_fault !! 590 ldq $17, SP_OFF+32($sp)
116 !! 591 ldq $18, SP_OFF+40($sp)
117 END(EV_MachineCheck) !! 592 ldq $19, 72($sp)
118 !! 593 ldq $20, 80($sp)
119 ; -------------------------------------------- !! 594 ldq $21, 88($sp)
120 ; Privilege Violation Exception Handler !! 595
121 ; -------------------------------------------- !! 596 /* get the system call pointer.. */
122 ENTRY(EV_PrivilegeV) !! 597 lda $1, NR_syscalls($31)
123 !! 598 lda $2, sys_call_table
124 EXCEPTION_PROLOGUE !! 599 lda $27, sys_ni_syscall
125 !! 600 cmpult $0, $1, $1
126 bl do_privilege_fault !! 601 s8addq $0, $2, $2
127 b ret_from_exception !! 602 beq $1, 1f
128 END(EV_PrivilegeV) !! 603 ldq $27, 0($2)
129 !! 604 1: jsr $26, ($27), sys_gettimeofday
130 ; -------------------------------------------- !! 605 ret_from_straced:
131 ; Extension Instruction Exception Handler !! 606 ldgp $gp, 0($26)
132 ; -------------------------------------------- !! 607
133 ENTRY(EV_Extension) !! 608 /* check return.. */
134 !! 609 blt $0, $strace_error /* the call failed */
135 EXCEPTION_PROLOGUE !! 610 $strace_success:
136 !! 611 stq $31, 72($sp) /* a3=0 => no error */
137 bl do_extension_fault !! 612 stq $0, 0($sp) /* save return value */
138 b ret_from_exception !! 613
139 END(EV_Extension) !! 614 DO_SWITCH_STACK
140 !! 615 jsr $26, syscall_trace_leave
141 ;################ Trap Handling (Syscall, Brea !! 616 UNDO_SWITCH_STACK
142 !! 617 br $31, ret_from_sys_call
143 ; -------------------------------------------- !! 618
144 ; syscall Tracing !! 619 .align 3
145 ; -------------------------------------------- !! 620 $strace_error:
146 tracesys: !! 621 ldq $18, 0($sp) /* old syscall nr (zero if success) */
147 ; safekeep EFA (r12) if syscall tracer !! 622 beq $18, $strace_success
148 ; for traps, ERET is pre-commit so poi !! 623 ldq $19, 72($sp) /* .. and this a3 */
149 GET_CURR_TASK_FIELD_PTR TASK_THREAD, !! 624
150 st r12, [r11, THREAD_FAULT_ADDR] !! 625 subq $31, $0, $0 /* with error in v0 */
151 !! 626 addq $31, 1, $1 /* set a3 for errno return */
152 ; PRE syscall trace hook !! 627 stq $0, 0($sp)
153 mov r0, sp !! 628 stq $1, 72($sp) /* a3 for return */
154 bl @syscall_trace_enter !! 629
155 !! 630 DO_SWITCH_STACK
156 ; Tracing code now returns the syscall !! 631 mov $18, $9 /* save old syscall number */
157 mov r8, r0 !! 632 mov $19, $10 /* save old a3 */
158 !! 633 jsr $26, syscall_trace_leave
159 ; Do the Sys Call as we normally would !! 634 mov $9, $18
160 cmp r8, NR_syscalls - 1 !! 635 mov $10, $19
161 mov.hi r0, -ENOSYS !! 636 UNDO_SWITCH_STACK
162 bhi tracesys_exit !! 637
163 !! 638 mov $31, $26 /* tell "ret_from_sys_call" we can restart */
164 ; Restore the sys-call args. Mere invo !! 639 br ret_from_sys_call
165 ; clobbered them (since they are in sc !! 640 CFI_END_OSF_FRAME entSys
166 ; have deliberately changed the syscal !! 641
167 ld r0, [sp, PT_r0] !! 642 /*
168 ld r1, [sp, PT_r1] !! 643 * Save and restore the switch stack -- aka the balance of the user context.
169 ld r2, [sp, PT_r2] !! 644 */
170 ld r3, [sp, PT_r3] <<
171 ld r4, [sp, PT_r4] <<
172 ld r5, [sp, PT_r5] <<
173 ld r6, [sp, PT_r6] <<
174 ld r7, [sp, PT_r7] <<
175 ld.as r9, [sys_call_table, r8] <<
176 jl [r9] <<
177 <<
178 tracesys_exit: <<
179 st r0, [sp, PT_r0] <<
180 <<
181 ; POST syscall trace hook <<
182 mov r0, sp ; pt_regs need <<
183 bl @syscall_trace_exit <<
184 <<
185 ; don't call ret_from_system_call as i <<
186 b ret_from_exception <<
187 <<
188 ; -------------------------------------------- <<
189 ; Breakpoint TRAP <<
190 ; -------------------------------------------- <<
191 trap_with_param: <<
192 mov r0, r12 ; EFA in case ptracer/ <<
193 mov r1, sp ; pt_regs <<
194 <<
195 ; save callee regs in case tracer/gdb <<
196 SAVE_CALLEE_SAVED_USER <<
197 <<
198 ; safekeep ref to callee regs <<
199 GET_CURR_TASK_FIELD_PTR TASK_THREAD, <<
200 st sp, [r10, THREAD_CALLEE_REG] <<
201 <<
202 ; call the non syscall trap handler <<
203 bl do_non_swi_trap <<
204 <<
205 ; unwind stack to discard callee regs <<
206 DISCARD_CALLEE_SAVED_USER <<
207 <<
208 b ret_from_exception <<
209 <<
210 ; -------------------------------------------- <<
211 ; syscall TRAP <<
212 ; ABI: (r0-r7) up to 8 args, (r8) syscall numb <<
213 ; -------------------------------------------- <<
214 <<
215 ENTRY(EV_Trap) <<
216 <<
217 EXCEPTION_PROLOGUE_KEEP_AE <<
218 <<
219 lr r12, [efa] <<
220 <<
221 FAKE_RET_FROM_EXCPN <<
222 <<
223 ;============ TRAP N : breakpoints, kp <<
224 bmsk.f 0, r10, 7 <<
225 bnz trap_with_param <<
226 <<
227 ;============ TRAP 0 (no param): sysca <<
228 <<
229 ; syscall tracing ongoing, invoke pre- <<
230 GET_CURR_THR_INFO_FLAGS r10 <<
231 and.f 0, r10, _TIF_SYSCALL_WORK <<
232 bnz tracesys ; this never comes bac <<
233 <<
234 ;============ Normal syscall case <<
235 <<
236 cmp r8, NR_syscalls - 1 <<
237 mov.hi r0, -ENOSYS <<
238 bhi .Lret_from_system_call <<
239 <<
240 ld.as r9,[sys_call_table, r8] <<
241 jl [r9] <<
242 <<
243 .Lret_from_system_call: <<
244 st r0, [sp, PT_r0] ; sys call ret <<
245 <<
246 ; fall through to ret_from_exception <<
247 END(EV_Trap) <<
248 <<
249 ;############# Return from Intr/Excp/Trap (Lin <<
250 ; <<
251 ; If ret to user mode do we need to handle sig <<
252 <<
253 ENTRY(ret_from_exception) <<
254 <<
255 ; Pre-{IRQ,Trap,Exception} K/U mode fr <<
256 ld r8, [sp, PT_status32] ; returnin <<
257 <<
258 bbit0 r8, STATUS_U_BIT, resume_kernel <<
259 <<
260 ; Before returning to User mode check- <<
261 ; such as rescheduling/signal-delivery <<
262 resume_user_mode_begin: <<
263 <<
264 ; Disable IRQs to ensures that chk for <<
265 ; (and we don't end up missing a NEED_ <<
266 ; interim IRQ). <<
267 IRQ_DISABLE r10 <<
268 <<
269 ; Fast Path return to user mode if no <<
270 GET_CURR_THR_INFO_FLAGS r9 <<
271 and.f 0, r9, _TIF_WORK_MASK <<
272 bz .Lrestore_regs <<
273 <<
274 ; --- (Slow Path #1) task preemption - <<
275 bbit0 r9, TIF_NEED_RESCHED, .Lchk_pen <<
276 mov blink, resume_user_mode_begin <<
277 j @schedule ; BTST+Bnz cau <<
278 <<
279 .Lchk_pend_signals: <<
280 IRQ_ENABLE r10 <<
281 <<
282 ; --- (Slow Path #2) pending signal - <<
283 mov r0, sp ; pt_regs for arg to d <<
284 <<
285 GET_CURR_THR_INFO_FLAGS r9 <<
286 and.f 0, r9, _TIF_SIGPENDING|_TIF_NO <<
287 bz .Lchk_notify_resume <<
288 <<
289 ; Normal Trap/IRQ entry only saves Scr <<
290 ; in pt_reg since the "C" ABI (kernel <<
291 ; save/restore callee-saved regs. <<
292 ; <<
293 ; However, here we need to explicitly <<
294 ; (i) If this signal causes coredump <<
295 ; (ii) If signal is SIGTRAP/SIGSTOP, t <<
296 ; tracer might call PEEKUSR(CALLE <<
297 ; <<
298 ; NOTE: SP will grow up by size of CAL <<
299 SAVE_CALLEE_SAVED_USER <<
300 <<
301 ; save location of saved Callee Regs @ <<
302 GET_CURR_TASK_FIELD_PTR TASK_THREAD, <<
303 st sp, [r10, THREAD_CALLEE_REG] <<
304 <<
305 bl @do_signal <<
306 <<
307 ; Ideally we want to discard the Calle <<
308 ; a tracing signal, tracer could have <<
309 RESTORE_CALLEE_SAVED_USER <<
310 <<
311 b resume_user_mode_begin ; loop <<
312 <<
313 ; --- (Slow Path #3) notify_resume --- <<
314 .Lchk_notify_resume: <<
315 btst r9, TIF_NOTIFY_RESUME <<
316 blnz @do_notify_resume <<
317 b resume_user_mode_begin ; unco <<
318 ; for <<
319 <<
320 resume_kernel_mode: <<
321 <<
322 ; Disable Interrupts from this point o <<
323 ; CONFIG_PREEMPTION: This is a must fo <<
324 ; !CONFIG_PREEMPTION: To ensure restor <<
325 IRQ_DISABLE r9 <<
326 <<
327 #ifdef CONFIG_PREEMPTION <<
328 645
329 ; Can't preempt if preemption disabled !! 646 .align 4
330 GET_CURR_THR_INFO_FROM_SP r10 !! 647 .type do_switch_stack, @function
331 ld r8, [r10, THREAD_INFO_PREEMPT_COUN !! 648 .cfi_startproc simple
332 brne r8, 0, .Lrestore_regs !! 649 .cfi_return_column 64
>> 650 .cfi_def_cfa $sp, 0
>> 651 .cfi_register 64, $1
>> 652 do_switch_stack:
>> 653 lda $sp, -SWITCH_STACK_SIZE($sp)
>> 654 .cfi_adjust_cfa_offset SWITCH_STACK_SIZE
>> 655 stq $9, 0($sp)
>> 656 stq $10, 8($sp)
>> 657 stq $11, 16($sp)
>> 658 stq $12, 24($sp)
>> 659 stq $13, 32($sp)
>> 660 stq $14, 40($sp)
>> 661 stq $15, 48($sp)
>> 662 stq $26, 56($sp)
>> 663 ret $31, ($1), 1
>> 664 .cfi_endproc
>> 665 .size do_switch_stack, .-do_switch_stack
>> 666
>> 667 .align 4
>> 668 .type undo_switch_stack, @function
>> 669 .cfi_startproc simple
>> 670 .cfi_def_cfa $sp, 0
>> 671 .cfi_register 64, $1
>> 672 undo_switch_stack:
>> 673 ldq $9, 0($sp)
>> 674 ldq $10, 8($sp)
>> 675 ldq $11, 16($sp)
>> 676 ldq $12, 24($sp)
>> 677 ldq $13, 32($sp)
>> 678 ldq $14, 40($sp)
>> 679 ldq $15, 48($sp)
>> 680 ldq $26, 56($sp)
>> 681 lda $sp, SWITCH_STACK_SIZE($sp)
>> 682 ret $31, ($1), 1
>> 683 .cfi_endproc
>> 684 .size undo_switch_stack, .-undo_switch_stack
>> 685
>> 686 #define FR(n) n * 8 + TI_FP($8)
>> 687 .align 4
>> 688 .globl __save_fpu
>> 689 .type __save_fpu, @function
>> 690 __save_fpu:
>> 691 #define V(n) stt $f##n, FR(n)
>> 692 V( 0); V( 1); V( 2); V( 3)
>> 693 V( 4); V( 5); V( 6); V( 7)
>> 694 V( 8); V( 9); V(10); V(11)
>> 695 V(12); V(13); V(14); V(15)
>> 696 V(16); V(17); V(18); V(19)
>> 697 V(20); V(21); V(22); V(23)
>> 698 V(24); V(25); V(26); V(27)
>> 699 mf_fpcr $f0 # get fpcr
>> 700 V(28); V(29); V(30)
>> 701 stt $f0, FR(31) # save fpcr in slot of $f31
>> 702 ldt $f0, FR(0) # don't let "__save_fpu" change fp state.
>> 703 ret
>> 704 #undef V
>> 705 .size __save_fpu, .-__save_fpu
>> 706
>> 707 .align 4
>> 708 restore_fpu:
>> 709 and $3, TS_RESTORE_FP, $3
>> 710 bic $2, TS_SAVED_FP | TS_RESTORE_FP, $2
>> 711 beq $3, 1f
>> 712 #define V(n) ldt $f##n, FR(n)
>> 713 ldt $f30, FR(31) # get saved fpcr
>> 714 V( 0); V( 1); V( 2); V( 3)
>> 715 mt_fpcr $f30 # install saved fpcr
>> 716 V( 4); V( 5); V( 6); V( 7)
>> 717 V( 8); V( 9); V(10); V(11)
>> 718 V(12); V(13); V(14); V(15)
>> 719 V(16); V(17); V(18); V(19)
>> 720 V(20); V(21); V(22); V(23)
>> 721 V(24); V(25); V(26); V(27)
>> 722 V(28); V(29); V(30)
>> 723 1: stl $2, TI_STATUS($8)
>> 724 br restore_other
>> 725 #undef V
333 726
334 ; check if this task's NEED_RESCHED fl !! 727
335 ld r9, [r10, THREAD_INFO_FLAGS] !! 728 /*
336 bbit0 r9, TIF_NEED_RESCHED, .Lrestore !! 729 * The meat of the context switch code.
>> 730 */
>> 731 .align 4
>> 732 .globl alpha_switch_to
>> 733 .type alpha_switch_to, @function
>> 734 .cfi_startproc
>> 735 alpha_switch_to:
>> 736 DO_SWITCH_STACK
>> 737 ldl $1, TI_STATUS($8)
>> 738 and $1, TS_RESTORE_FP, $3
>> 739 bne $3, 1f
>> 740 or $1, TS_RESTORE_FP | TS_SAVED_FP, $2
>> 741 and $1, TS_SAVED_FP, $3
>> 742 stl $2, TI_STATUS($8)
>> 743 bne $3, 1f
>> 744 bsr $26, __save_fpu
>> 745 1:
>> 746 call_pal PAL_swpctx
>> 747 lda $8, 0x3fff
>> 748 UNDO_SWITCH_STACK
>> 749 bic $sp, $8, $8
>> 750 mov $17, $0
>> 751 ret
>> 752 .cfi_endproc
>> 753 .size alpha_switch_to, .-alpha_switch_to
337 754
338 ; Invoke PREEMPTION !! 755 /*
339 jl preempt_schedule_irq !! 756 * New processes begin life here.
>> 757 */
340 758
341 ; preempt_schedule_irq() always return !! 759 .globl ret_from_fork
342 #endif !! 760 .align 4
>> 761 .ent ret_from_fork
>> 762 ret_from_fork:
>> 763 lda $26, ret_to_user
>> 764 mov $17, $16
>> 765 jmp $31, schedule_tail
>> 766 .end ret_from_fork
343 767
344 b .Lrestore_regs !! 768 /*
>> 769 * ... and new kernel threads - here
>> 770 */
>> 771 .align 4
>> 772 .globl ret_from_kernel_thread
>> 773 .ent ret_from_kernel_thread
>> 774 ret_from_kernel_thread:
>> 775 mov $17, $16
>> 776 jsr $26, schedule_tail
>> 777 mov $9, $27
>> 778 mov $10, $16
>> 779 jsr $26, ($9)
>> 780 br $31, ret_to_user
>> 781 .end ret_from_kernel_thread
345 782
346 ##### DONT ADD CODE HERE - .Lrestore_regs actu !! 783
>> 784 /*
>> 785 * Special system calls. Most of these are special in that they either
>> 786 * have to play switch_stack games.
>> 787 */
347 788
>> 789 .macro fork_like name
>> 790 .align 4
>> 791 .globl alpha_\name
>> 792 .ent alpha_\name
>> 793 alpha_\name:
>> 794 .prologue 0
>> 795 bsr $1, do_switch_stack
>> 796 // NB: if anyone adds preemption, this block will need to be protected
>> 797 ldl $1, TI_STATUS($8)
>> 798 and $1, TS_SAVED_FP, $3
>> 799 or $1, TS_SAVED_FP, $2
>> 800 bne $3, 1f
>> 801 stl $2, TI_STATUS($8)
>> 802 bsr $26, __save_fpu
>> 803 1:
>> 804 jsr $26, sys_\name
>> 805 ldq $26, 56($sp)
>> 806 lda $sp, SWITCH_STACK_SIZE($sp)
>> 807 ret
>> 808 .end alpha_\name
>> 809 .endm
>> 810
>> 811 fork_like fork
>> 812 fork_like vfork
>> 813 fork_like clone
>> 814 fork_like clone3
>> 815
>> 816 .macro sigreturn_like name
>> 817 .align 4
>> 818 .globl sys_\name
>> 819 .ent sys_\name
>> 820 sys_\name:
>> 821 .prologue 0
>> 822 lda $9, ret_from_straced
>> 823 cmpult $26, $9, $9
>> 824 lda $sp, -SWITCH_STACK_SIZE($sp)
>> 825 jsr $26, do_\name
>> 826 bne $9, 1f
>> 827 jsr $26, syscall_trace_leave
>> 828 1: br $1, undo_switch_stack
>> 829 br ret_from_sys_call
>> 830 .end sys_\name
>> 831 .endm
>> 832
>> 833 sigreturn_like sigreturn
>> 834 sigreturn_like rt_sigreturn
>> 835
>> 836 .align 4
>> 837 .globl alpha_syscall_zero
>> 838 .ent alpha_syscall_zero
>> 839 alpha_syscall_zero:
>> 840 .prologue 0
>> 841 /* Special because it needs to do something opposite to
>> 842 force_successful_syscall_return(). We use the saved
>> 843 syscall number for that, zero meaning "not an error".
>> 844 That works nicely, but for real syscall 0 we need to
>> 845 make sure that this logics doesn't get confused.
>> 846 Store a non-zero there - -ENOSYS we need in register
>> 847 for our return value will do just fine.
>> 848 */
>> 849 lda $0, -ENOSYS
>> 850 unop
>> 851 stq $0, 0($sp)
>> 852 ret
>> 853 .end alpha_syscall_zero
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