1 /* SPDX-License-Identifier: GPL-2.0 */ 1 /* SPDX-License-Identifier: GPL-2.0 */
2 /* 2 /*
3 * Copyright (C) 2020-2022 Loongson Technology !! 3 * arch/alpha/kernel/entry.S
4 * 4 *
5 * Derived from MIPS: !! 5 * Kernel entry-points.
6 * Copyright (C) 1994 - 2000, 2001, 2003 Ralf <<
7 * Copyright (C) 1999, 2000 Silicon Graphics, <<
8 * Copyright (C) 2001 MIPS Technologies, Inc. <<
9 */ 6 */
10 7
11 #include <asm/asm.h> !! 8 #include <asm/asm-offsets.h>
12 #include <asm/asmmacro.h> <<
13 #include <asm/loongarch.h> <<
14 #include <asm/regdef.h> <<
15 #include <asm/stackframe.h> <<
16 #include <asm/thread_info.h> 9 #include <asm/thread_info.h>
17 #include <asm/unwind_hints.h> !! 10 #include <asm/pal.h>
>> 11 #include <asm/errno.h>
>> 12 #include <asm/unistd.h>
18 13
19 .text 14 .text
>> 15 .set noat
20 .cfi_sections .debug_frame 16 .cfi_sections .debug_frame
21 .align 5 !! 17
22 SYM_CODE_START(handle_syscall) !! 18 /* Stack offsets. */
23 UNWIND_HINT_UNDEFINED !! 19 #define SP_OFF 184
24 csrrd t0, PERCPU_BASE_KS !! 20 #define SWITCH_STACK_SIZE 64
25 la.pcrel t1, kernelsp !! 21
26 add.d t1, t1, t0 !! 22 .macro CFI_START_OSF_FRAME func
27 move t2, sp !! 23 .align 4
28 ld.d sp, t1, 0 !! 24 .globl \func
29 !! 25 .type \func,@function
30 addi.d sp, sp, -PT_SIZE !! 26 \func:
31 cfi_st t2, PT_R3 !! 27 .cfi_startproc simple
32 cfi_rel_offset sp, PT_R3 !! 28 .cfi_return_column 64
33 st.d zero, sp, PT_R0 !! 29 .cfi_def_cfa $sp, 48
34 csrrd t2, LOONGARCH_CSR_PRMD !! 30 .cfi_rel_offset 64, 8
35 st.d t2, sp, PT_PRMD !! 31 .cfi_rel_offset $gp, 16
36 csrrd t2, LOONGARCH_CSR_CRMD !! 32 .cfi_rel_offset $16, 24
37 st.d t2, sp, PT_CRMD !! 33 .cfi_rel_offset $17, 32
38 csrrd t2, LOONGARCH_CSR_EUEN !! 34 .cfi_rel_offset $18, 40
39 st.d t2, sp, PT_EUEN !! 35 .endm
40 csrrd t2, LOONGARCH_CSR_ECFG !! 36
41 st.d t2, sp, PT_ECFG !! 37 .macro CFI_END_OSF_FRAME func
42 csrrd t2, LOONGARCH_CSR_ESTA !! 38 .cfi_endproc
43 st.d t2, sp, PT_ESTAT !! 39 .size \func, . - \func
44 cfi_st ra, PT_R1 !! 40 .endm
45 cfi_st a0, PT_R4 !! 41
46 cfi_st a1, PT_R5 !! 42 /*
47 cfi_st a2, PT_R6 !! 43 * This defines the normal kernel pt-regs layout.
48 cfi_st a3, PT_R7 !! 44 *
49 cfi_st a4, PT_R8 !! 45 * regs 9-15 preserved by C code
50 cfi_st a5, PT_R9 !! 46 * regs 16-18 saved by PAL-code
51 cfi_st a6, PT_R10 !! 47 * regs 29-30 saved and set up by PAL-code
52 cfi_st a7, PT_R11 !! 48 * JRP - Save regs 16-18 in a special area of the stack, so that
53 csrrd ra, LOONGARCH_CSR_ERA !! 49 * the palcode-provided values are available to the signal handler.
54 st.d ra, sp, PT_ERA !! 50 */
55 cfi_rel_offset ra, PT_ERA !! 51
56 !! 52 .macro SAVE_ALL
57 cfi_st tp, PT_R2 !! 53 subq $sp, SP_OFF, $sp
58 cfi_st u0, PT_R21 !! 54 .cfi_adjust_cfa_offset SP_OFF
59 cfi_st fp, PT_R22 !! 55 stq $0, 0($sp)
60 !! 56 stq $1, 8($sp)
61 SAVE_STATIC !! 57 stq $2, 16($sp)
62 UNWIND_HINT_REGS !! 58 stq $3, 24($sp)
63 !! 59 stq $4, 32($sp)
64 #ifdef CONFIG_KGDB !! 60 stq $28, 144($sp)
65 li.w t1, CSR_CRMD_WE !! 61 .cfi_rel_offset $0, 0
66 csrxchg t1, t1, LOONGARCH_CSR_ !! 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
>> 175
>> 176 /*
>> 177 * Non-syscall kernel entry points.
>> 178 */
>> 179
>> 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 */
>> 443
>> 444 .align 4
>> 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 */
67 #endif 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
>> 533
>> 534 /*
>> 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 */
>> 544
>> 545 .align 4
>> 546 .type work_pending, @function
>> 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
>> 567
>> 568 /*
>> 569 * PTRACE syscall handler
>> 570 */
>> 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
>> 583 1:
>> 584 DO_SWITCH_STACK
>> 585 jsr $26, syscall_trace_enter /* returns the syscall number */
>> 586 UNDO_SWITCH_STACK
>> 587
>> 588 /* get the arguments back.. */
>> 589 ldq $16, SP_OFF+24($sp)
>> 590 ldq $17, SP_OFF+32($sp)
>> 591 ldq $18, SP_OFF+40($sp)
>> 592 ldq $19, 72($sp)
>> 593 ldq $20, 80($sp)
>> 594 ldq $21, 88($sp)
>> 595
>> 596 /* get the system call pointer.. */
>> 597 lda $1, NR_syscalls($31)
>> 598 lda $2, sys_call_table
>> 599 lda $27, sys_ni_syscall
>> 600 cmpult $0, $1, $1
>> 601 s8addq $0, $2, $2
>> 602 beq $1, 1f
>> 603 ldq $27, 0($2)
>> 604 1: jsr $26, ($27), sys_gettimeofday
>> 605 ret_from_straced:
>> 606 ldgp $gp, 0($26)
>> 607
>> 608 /* check return.. */
>> 609 blt $0, $strace_error /* the call failed */
>> 610 $strace_success:
>> 611 stq $31, 72($sp) /* a3=0 => no error */
>> 612 stq $0, 0($sp) /* save return value */
>> 613
>> 614 DO_SWITCH_STACK
>> 615 jsr $26, syscall_trace_leave
>> 616 UNDO_SWITCH_STACK
>> 617 br $31, ret_from_sys_call
>> 618
>> 619 .align 3
>> 620 $strace_error:
>> 621 ldq $18, 0($sp) /* old syscall nr (zero if success) */
>> 622 beq $18, $strace_success
>> 623 ldq $19, 72($sp) /* .. and this a3 */
>> 624
>> 625 subq $31, $0, $0 /* with error in v0 */
>> 626 addq $31, 1, $1 /* set a3 for errno return */
>> 627 stq $0, 0($sp)
>> 628 stq $1, 72($sp) /* a3 for return */
>> 629
>> 630 DO_SWITCH_STACK
>> 631 mov $18, $9 /* save old syscall number */
>> 632 mov $19, $10 /* save old a3 */
>> 633 jsr $26, syscall_trace_leave
>> 634 mov $9, $18
>> 635 mov $10, $19
>> 636 UNDO_SWITCH_STACK
>> 637
>> 638 mov $31, $26 /* tell "ret_from_sys_call" we can restart */
>> 639 br ret_from_sys_call
>> 640 CFI_END_OSF_FRAME entSys
>> 641
>> 642 /*
>> 643 * Save and restore the switch stack -- aka the balance of the user context.
>> 644 */
>> 645
>> 646 .align 4
>> 647 .type do_switch_stack, @function
>> 648 .cfi_startproc simple
>> 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
>> 726
>> 727
>> 728 /*
>> 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
>> 754
>> 755 /*
>> 756 * New processes begin life here.
>> 757 */
>> 758
>> 759 .globl ret_from_fork
>> 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
>> 767
>> 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
>> 782
>> 783
>> 784 /*
>> 785 * Special system calls. Most of these are special in that they either
>> 786 * have to play switch_stack games.
>> 787 */
68 788
69 move u0, t0 !! 789 .macro fork_like name
70 li.d tp, ~_THREAD_MASK !! 790 .align 4
71 and tp, tp, sp !! 791 .globl alpha_\name
72 !! 792 .ent alpha_\name
73 move a0, sp !! 793 alpha_\name:
74 bl do_syscall !! 794 .prologue 0
75 !! 795 bsr $1, do_switch_stack
76 RESTORE_ALL_AND_RET !! 796 // NB: if anyone adds preemption, this block will need to be protected
77 SYM_CODE_END(handle_syscall) !! 797 ldl $1, TI_STATUS($8)
78 _ASM_NOKPROBE(handle_syscall) !! 798 and $1, TS_SAVED_FP, $3
79 !! 799 or $1, TS_SAVED_FP, $2
80 SYM_CODE_START(ret_from_fork) !! 800 bne $3, 1f
81 UNWIND_HINT_REGS !! 801 stl $2, TI_STATUS($8)
82 bl schedule_tail !! 802 bsr $26, __save_fpu
83 move a0, sp !! 803 1:
84 bl syscall_exit_to_user_m !! 804 jsr $26, sys_\name
85 RESTORE_STATIC !! 805 ldq $26, 56($sp)
86 RESTORE_SOME !! 806 lda $sp, SWITCH_STACK_SIZE($sp)
87 RESTORE_SP_AND_RET !! 807 ret
88 SYM_CODE_END(ret_from_fork) !! 808 .end alpha_\name
89 !! 809 .endm
90 SYM_CODE_START(ret_from_kernel_thread) !! 810
91 UNWIND_HINT_REGS !! 811 fork_like fork
92 bl schedule_tail !! 812 fork_like vfork
93 move a0, s1 !! 813 fork_like clone
94 jirl ra, s0, 0 !! 814 fork_like clone3
95 move a0, sp !! 815
96 bl syscall_exit_to_user_m !! 816 .macro sigreturn_like name
97 RESTORE_STATIC !! 817 .align 4
98 RESTORE_SOME !! 818 .globl sys_\name
99 RESTORE_SP_AND_RET !! 819 .ent sys_\name
100 SYM_CODE_END(ret_from_kernel_thread) !! 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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