1/* 2 * (C) Copyright 2003, Psyent Corporation <www.psyent.com> 3 * Scott McNutt <smcnutt@psyent.com> 4 * 5 * See file CREDITS for list of people who contributed to this 6 * project. 7 * 8 * This program is free software; you can redistribute it and/or 9 * modify it under the terms of the GNU General Public License as 10 * published by the Free Software Foundation; either version 2 of 11 * the License, or (at your option) any later version. 12 * 13 * This program is distributed in the hope that it will be useful, 14 * but WITHOUT ANY WARRANTY; without even the implied warranty of 15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 16 * GNU General Public License for more details. 17 * 18 * You should have received a copy of the GNU General Public License 19 * along with this program; if not, write to the Free Software 20 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, 21 * MA 02111-1307 USA 22 */ 23 24#include <config.h> 25 26/************************************************************************* 27 * Register window underflow 28 * 29 * The register window underflow exception occurs whenever the lowest 30 * valid register window is in use (CWP=LO_LIMIT) and a save instruction 31 * is issued. The save moves CWP below LO_LIMIT, %sp is set as normal, 32 * then the exception is generated prior to executing the instruction 33 * after the save. 34 ************************************************************************/ 35 .text 36 .global _cwp_lolimit 37 .align 4 38 39_cwp_lolimit: 40 41 /* Sixteen words are always allocated by the compiler in every 42 * procedure's stack frame, always starting at %sp, for saving 43 * 'in' and 'local' registers on a window overflow. 44 * 45 * Save the 'global' and 'in' regs on stack. They are restored 46 * at cwp = HI_LIMIT. The 'local' regs aren't in-use at this point. 47 */ 48 sts [%sp,0], %g0 /* Save 'global' regs*/ 49 sts [%sp,1], %g1 50 sts [%sp,2], %g2 51 sts [%sp,3], %g3 52 sts [%sp,4], %g4 53 sts [%sp,5], %g5 54 sts [%sp,6], %g6 55 sts [%sp,7], %g7 56 57 sts [%sp,8], %i0 /* Save 'in' regs */ 58 sts [%sp,9], %i1 59 sts [%sp,10], %i2 60 sts [%sp,11], %i3 61 sts [%sp,12], %i4 62 sts [%sp,13], %i5 63 sts [%sp,14], %i6 64 sts [%sp,15], %i7 65 66 /* Save current %sp and return address in a global so they are 67 * available at cwp = HI_LIMIT ... where the 'global'/'in' regs 68 * are restored. NOTE: %sp changes with cwp. 69 */ 70 mov %g7, %o7 71 mov %g6, %sp 72 73 /* Get LO_LIMIT/HI_LIMIT to know where to start & stop. Note: in 74 * the underflow exception, cwp is __NOT__ guaranteed to be zero. 75 * If the OCI debug module is enabled the reset value for LO_LIMIT 76 * is 2, not 1 -- so cwp can be 1 or 0. 77 */ 78 pfx 2 /* WVALID */ 79 rdctl %g1 80 mov %g2, %g1 81 pfx 0 82 and %g1, 0x1f /* g1 <- LO_LIMIT */ 83 lsri %g2, 5 84 pfx 0 85 and %g2,0x1f /* g2 <- HI_LIMIT */ 86 87 /* Set istatus so cwp = HI_LIMIT after tret 88 */ 89 movi %g5, 0x1f 90 lsli %g5, 4 91 not %g5 /* mask to clr cwp */ 92 pfx 1 /* istatus */ 93 rdctl %g0 94 and %g0, %g5 /* clear cwp field */ 95 96 mov %g4, %g2 97 lsli %g4, 4 98 or %g0, %g4 /* cwp = HI_LIMIT */ 99 pfx 1 100 wrctl %g0 /* update istatus */ 101 102 /* Now move up the register file, saving as we go. When loop 103 * is first entered, %g1 is at LO_LIMIT. 104 */ 1050: 106 restore /* cwp++ */ 107 sts [%sp,0], %l0 /* Save "local" regs*/ 108 sts [%sp,1], %l1 109 sts [%sp,2], %l2 110 sts [%sp,3], %l3 111 sts [%sp,4], %l4 112 sts [%sp,5], %l5 113 sts [%sp,6], %l6 114 sts [%sp,7], %l7 115 116 sts [%sp,8], %i0 /* Save 'in' regs */ 117 sts [%sp,9], %i1 118 sts [%sp,10], %i2 119 sts [%sp,11], %i3 120 sts [%sp,12], %i4 121 sts [%sp,13], %i5 122 sts [%sp,14], %i6 123 sts [%sp,15], %i7 124 125 cmp %g1, %g2 /* cwp == HI_LIMIT ? */ 126 skps cc_ne /* if so, we're done */ 127 br 1f 128 nop /* delay slot */ 129 130 inc %g1 /* g1 <- cwp++ */ 131 br 0b 132 nop /* delay slot */ 133 134 /* At this point cwp = HI_LIMIT, so the global/in regs that were 135 * in place when the underflow occurred must be restored using 136 * the original stack pointer (saved in g6). 137 */ 1381: 139 mov %o7, %g7 /* restore return addr */ 140 mov %sp, %g6 /* Restore original sp */ 141 142 lds %g0, [%sp,0] /* Restore 'global' regs*/ 143 lds %g1, [%sp,1] 144 lds %g2, [%sp,2] 145 lds %g3, [%sp,3] 146 lds %g4, [%sp,4] 147 lds %g5, [%sp,5] 148 lds %g6, [%sp,6] 149 lds %g7, [%sp,7] 150 151 lds %i0, [%sp,8] /* Restore 'in' regs*/ 152 lds %i1, [%sp,9] 153 lds %i2, [%sp,10] 154 lds %i3, [%sp,11] 155 lds %i4, [%sp,12] 156 lds %i5, [%sp,13] 157 lds %i6, [%sp,14] 158 lds %i7, [%sp,15] 159 160 tret %o7 /* All done */ 161 162/************************************************************************* 163 * Register window overflow 164 * 165 * The register window overflow exception occurs whenever the highest 166 * valid register window is in use (cwp = HI_LIMIT) and a restore 167 * instruction is issued. Control is transferred to the overflow handler 168 * before the instruction following restore is executed. 169 * 170 * When a register window overflow exception is taken, the exception 171 * handler sees cwp at HI_LIMIT. 172 ************************************************************************/ 173 .text 174 .global _cwp_hilimit 175 .align 4 176 177_cwp_hilimit: 178 179 /* Save 'global'/'in' regs on the stack -- will restore when cwp 180 * is at LO_LIMIT. Locals don't need saving as they are going away. 181 */ 182 sts [%sp,0], %g0 /* Save "global" regs*/ 183 sts [%sp,1], %g1 184 sts [%sp,2], %g2 185 sts [%sp,3], %g3 186 sts [%sp,4], %g4 187 sts [%sp,5], %g5 188 sts [%sp,6], %g6 189 sts [%sp,7], %g7 190 191 sts [%sp,8], %i0 /* Save 'in' regs */ 192 sts [%sp,9], %i1 193 sts [%sp,10], %i2 194 sts [%sp,11], %i3 195 sts [%sp,12], %i4 196 sts [%sp,13], %i5 197 sts [%sp,14], %i6 198 sts [%sp,15], %i7 199 200 /* The current %sp must be available in global to restore regs 201 * saved on stack. Need return addr as well ;-) 202 */ 203 mov %g7, %o7 204 mov %g6, %sp 205 206 /* Get HI_LIMIT & LO_LIMIT 207 */ 208 pfx 2 /* WVALID */ 209 rdctl %g1 210 mov %g2, %g1 211 pfx 0 212 and %g1, 0x1f /* g1 <- LO_LIMIT */ 213 lsri %g2, 5 214 pfx 0 215 and %g2,0x1f /* g2 <- HI_LIMIT */ 216 217 /* Set istatus so cwp = LO_LIMIT after tret 218 */ 219 movi %g5, 0x1f 220 lsli %g5, 4 221 not %g5 /* mask to clr cwp */ 222 pfx 1 /* istatus */ 223 rdctl %g0 224 and %g0, %g5 /* clear cwp field */ 225 226 mov %g4, %g1 /* g4 <- LO_LIMIT */ 227 lsli %g4, 4 228 or %g0, %g4 /* cwp = LO_LIMIT */ 229 pfx 1 230 wrctl %g0 /* update istatus */ 231 232 /* Move to cwp = LO_LIMIT-1 and restore 'in' regs. 233 */ 234 subi %g4,(1 << 4) /* g4 <- LO_LIMIT - 1 */ 235 rdctl %g0 236 and %g0, %g5 /* clear cwp field */ 237 or %g0, %g4 /* cwp = LO_LIMIT - 1 */ 238 wrctl %g0 /* update status */ 239 nop 240 241 mov %sp, %g6 /* Restore sp */ 242 lds %i0, [%sp,8] /* Restore 'in' regs */ 243 lds %i1, [%sp,9] 244 lds %i2, [%sp,10] 245 lds %i3, [%sp,11] 246 lds %i4, [%sp,12] 247 lds %i5, [%sp,13] 248 lds %i6, [%sp,14] /* sp in next window */ 249 lds %i7, [%sp,15] 250 251 /* Starting at LO_LIMIT-1, move up the register file, restoring 252 * along the way. 253 */ 2540: 255 restore /* cwp++ */ 256 lds %l0, [%sp,0] /* Restore 'local' regs*/ 257 lds %l1, [%sp,1] 258 lds %l2, [%sp,2] 259 lds %l3, [%sp,3] 260 lds %l4, [%sp,4] 261 lds %l5, [%sp,5] 262 lds %l6, [%sp,6] 263 lds %l7, [%sp,7] 264 265 lds %i0, [%sp,8] /* Restore 'in' regs */ 266 lds %i1, [%sp,9] 267 lds %i2, [%sp,10] 268 lds %i3, [%sp,11] 269 lds %i4, [%sp,12] 270 lds %i5, [%sp,13] 271 lds %i6, [%sp,14] /* sp in next window */ 272 lds %i7, [%sp,15] 273 274 cmp %g1, %g2 /* cwp == HI_LIMIT ? */ 275 skps cc_ne /* if so, we're done */ 276 br 1f 277 nop /* delay slot */ 278 279 inc %g1 /* cwp++ */ 280 br 0b 281 nop /* delay slot */ 282 283 /* All windows have been updated at this point, but the globals 284 * still need to be restored. Go to cwp = LO_LIMIT-1 to get 285 * some registers to use. 286 */ 2871: 288 rdctl %g0 289 and %g0, %g5 /* clear cwp field */ 290 or %g0, %g4 /* cwp = LO_LIMIT - 1 */ 291 wrctl %g0 /* update status */ 292 nop 293 294 /* Now there are some registers available to use in restoring 295 * the globals. 296 */ 297 mov %sp, %g6 298 mov %o7, %g7 299 300 lds %g0, [%sp,0] /* Restore "global" regs*/ 301 lds %g1, [%sp,1] 302 lds %g2, [%sp,2] 303 lds %g3, [%sp,3] 304 lds %g4, [%sp,4] 305 lds %g5, [%sp,5] 306 lds %g6, [%sp,6] 307 lds %g7, [%sp,7] 308 309 /* The tret moves istatus -> status. istatus was already set for 310 * cwp = LO_LIMIT. 311 */ 312 313 tret %o7 /* done */ 314 315/************************************************************************* 316 * Default exception handler 317 * 318 * The default handler passes control to external_interrupt(). So trap 319 * or hardware interrupt hanlders can be installed using the familiar 320 * irq_install_handler(). 321 * 322 * Here, the stack is fixed-up and cwp is incremented prior to calling 323 * external_interrupt(). This lets the underflow and overflow handlers 324 * operate normally during the exception. 325 ************************************************************************/ 326 .text 327 .global _def_xhandler 328 .align 4 329 330_def_xhandler: 331 332 /* Allocate some stack space: 16 words at %sp to accomodate 333 * a reg window underflow, 8 words to save interrupted task's 334 * 'out' regs (which are now the 'in' regs), 8 words to preserve 335 * the 'global' regs and 3 words to save the return address, 336 * status and istatus. istatus must be saved in the event an 337 * underflow occurs in a dispatched handler. status is saved so 338 * a handler can access it on stack. 339 */ 340 pfx %hi((16+16+3) * 4) 341 subi %fp, %lo((16+16+3) * 4) 342 mov %sp, %fp 343 344 /* Save the 'global' regs and the interrupted task's 'out' regs 345 * (our 'in' regs) along with the return addr, status & istatus. 346 * First 16 words are for underflow exception. 347 */ 348 rdctl %l0 /* status */ 349 pfx 1 /* istatus */ 350 rdctl %l1 351 352 sts [%sp,16+0], %g0 /* Save 'global' regs*/ 353 sts [%sp,16+1], %g1 354 sts [%sp,16+2], %g2 355 sts [%sp,16+3], %g3 356 sts [%sp,16+4], %g4 357 sts [%sp,16+5], %g5 358 sts [%sp,16+6], %g6 359 sts [%sp,16+7], %g7 360 361 sts [%sp,16+8], %i0 /* Save 'in' regs */ 362 sts [%sp,16+9], %i1 363 sts [%sp,16+10], %i2 364 sts [%sp,16+11], %i3 365 sts [%sp,16+12], %i4 366 sts [%sp,16+13], %i5 367 sts [%sp,16+14], %i6 368 sts [%sp,16+15], %i7 369 370 sts [%sp,16+16], %l0 /* status */ 371 sts [%sp,16+17], %l1 /* istatus */ 372 sts [%sp,16+18], %o7 /* return addr */ 373 374 /* Move to cwp+1 ... this guarantees cwp is at or above LO_LIMIT. 375 * Need to set IPRI=3 and IE=1 to enable underflow exceptions. 376 * NOTE: only the 'out' regs have been saved ... can't touch 377 * the 'in' or 'local' here. 378 */ 379 restore /* cwp++ */ 380 rdctl %o0 /* o0 <- status */ 381 382 pfx %hi(0x7e00) 383 movi %o1, %lo(0x7e00) 384 not %o1 385 and %o0, %o1 /* clear IPRI */ 386 387 pfx %hi(0x8600) 388 movi %o1, %lo(0x8600) 389 or %o0, %o1 /* IPRI=3, IE=1 */ 390 391 wrctl %o0 /* o0 -> status */ 392 nop 393 394 /* It's ok to call a C routine now since cwp >= LO_LIMIT, 395 * interrupt task's registers are/will be preserved, and 396 * underflow exceptions can be handled. 397 */ 398 pfx %hi(external_interrupt@h) 399 movi %o1, %lo(external_interrupt@h) 400 pfx %xhi(external_interrupt@h) 401 movhi %o1, %xlo(external_interrupt@h) 402 bgen %o0, 4+2 /* 16 * 4 */ 403 add %o0, %sp /* Ptr to regs */ 404 call %o1 405 nop 406 407 /* Move back to the exception register window, restore the 'out' 408 * registers, then return from exception. 409 */ 410 rdctl %o0 /* o0 <- status */ 411 subi %o0, 16 412 wrctl %o0 /* cwp-- */ 413 nop 414 415 mov %sp, %fp 416 lds %g0, [%sp,16+0] /* Restore 'global' regs*/ 417 lds %g1, [%sp,16+1] 418 lds %g2, [%sp,16+2] 419 lds %g3, [%sp,16+3] 420 lds %g4, [%sp,16+4] 421 lds %g5, [%sp,16+5] 422 lds %g6, [%sp,16+6] 423 lds %g7, [%sp,16+7] 424 425 lds %i0, [%sp,16+8] /* Restore 'in' regs*/ 426 lds %i1, [%sp,16+9] 427 lds %i2, [%sp,16+10] 428 lds %i3, [%sp,16+11] 429 lds %i4, [%sp,16+12] 430 lds %i5, [%sp,16+13] 431 lds %i6, [%sp,16+14] 432 lds %i7, [%sp,16+15] 433 434 lds %l0, [%sp,16+16] /* status */ 435 lds %l1, [%sp,16+17] /* istatus */ 436 lds %o7, [%sp,16+18] /* return addr */ 437 438 pfx 1 439 wrctl %l1 /* restore istatus */ 440 441 pfx %hi((16+16+3) * 4) 442 addi %sp, %lo((16+16+3) * 4) 443 mov %fp, %sp 444 445 tret %o7 /* Done */ 446 447 448/************************************************************************* 449 * Timebase Timer Interrupt -- This has identical structure to above, 450 * but calls timer_interrupt(). Doing it this way keeps things similar 451 * to other architectures (e.g. ppc). 452 ************************************************************************/ 453 .text 454 .global _timebase_int 455 .align 4 456 457_timebase_int: 458 459 /* Allocate stack space. 460 */ 461 pfx %hi((16+16+3) * 4) 462 subi %fp, %lo((16+16+3) * 4) 463 mov %sp, %fp 464 465 /* Save the 'global' regs & 'out' regs (our 'in' regs) 466 */ 467 rdctl %l0 /* status */ 468 pfx 1 /* istatus */ 469 rdctl %l1 470 471 sts [%sp,16+0], %g0 /* Save 'global' regs*/ 472 sts [%sp,16+1], %g1 473 sts [%sp,16+2], %g2 474 sts [%sp,16+3], %g3 475 sts [%sp,16+4], %g4 476 sts [%sp,16+5], %g5 477 sts [%sp,16+6], %g6 478 sts [%sp,16+7], %g7 479 480 sts [%sp,16+8], %i0 /* Save 'in' regs */ 481 sts [%sp,16+9], %i1 482 sts [%sp,16+10], %i2 483 sts [%sp,16+11], %i3 484 sts [%sp,16+12], %i4 485 sts [%sp,16+13], %i5 486 sts [%sp,16+14], %i6 487 sts [%sp,16+15], %i7 488 489 sts [%sp,16+16], %l0 /* status */ 490 sts [%sp,16+17], %l1 /* istatus */ 491 sts [%sp,16+18], %o7 /* return addr */ 492 493 /* Move to cwp+1. 494 */ 495 restore /* cwp++ */ 496 rdctl %o0 /* o0 <- status */ 497 498 pfx %hi(0x7e00) 499 movi %o1, %lo(0x7e00) 500 not %o1 501 and %o0, %o1 /* clear IPRI */ 502 503 pfx %hi(0x8600) 504 movi %o1, %lo(0x8600) 505 or %o0, %o1 /* IPRI=3, IE=1 */ 506 507 wrctl %o0 /* o0 -> status */ 508 nop 509 510 /* Call timer_interrupt() 511 */ 512 pfx %hi(timer_interrupt@h) 513 movi %o1, %lo(timer_interrupt@h) 514 pfx %xhi(timer_interrupt@h) 515 movhi %o1, %xlo(timer_interrupt@h) 516 bgen %o0, 4+2 /* 16 * 4 */ 517 add %o0, %sp /* Ptr to regs */ 518 call %o1 519 nop 520 521 /* Move back to the exception register window, restore the 'out' 522 * registers, then return from exception. 523 */ 524 rdctl %o0 /* o0 <- status */ 525 subi %o0, 16 526 wrctl %o0 /* cwp-- */ 527 nop 528 529 mov %sp, %fp 530 lds %g0, [%sp,16+0] /* Restore 'global' regs*/ 531 lds %g1, [%sp,16+1] 532 lds %g2, [%sp,16+2] 533 lds %g3, [%sp,16+3] 534 lds %g4, [%sp,16+4] 535 lds %g5, [%sp,16+5] 536 lds %g6, [%sp,16+6] 537 lds %g7, [%sp,16+7] 538 539 lds %i0, [%sp,16+8] /* Restore 'in' regs*/ 540 lds %i1, [%sp,16+9] 541 lds %i2, [%sp,16+10] 542 lds %i3, [%sp,16+11] 543 lds %i4, [%sp,16+12] 544 lds %i5, [%sp,16+13] 545 lds %i6, [%sp,16+14] 546 lds %i7, [%sp,16+15] 547 548 lds %l0, [%sp,16+16] /* status */ 549 lds %l1, [%sp,16+17] /* istatus */ 550 lds %o7, [%sp,16+18] /* return addr */ 551 552 pfx 1 553 wrctl %l1 /* restore istatus */ 554 555 pfx %hi((16+16+3) * 4) 556 addi %sp, %lo((16+16+3) * 4) 557 mov %fp, %sp 558 559 tret %o7 /* Done */ 560 561/************************************************************************* 562 * GDB stubs 563 ************************************************************************/ 564 .text 565 .global _brkpt_hw_int, _brkpt_sw_int 566 .align 4 567 568_brkpt_hw_int: 569 movi %l1, 9 570 pfx 3 571 wrctl %l1 572 pfx 4 573 wrctl %l1 574 575_brkpt_sw_int: 576 movi %l1, 9 577 pfx 3 578 wrctl %l1 579 pfx 4 580 wrctl %l1 581 582 tret %o7 583