1 /* 2 * This file is subject to the terms and conditions of the GNU General Public 3 * License. See the file "COPYING" in the main directory of this archive 4 * for more details. 5 * 6 * Copyright (C) 2011 by Kevin Cernekee (cernekee@gmail.com) 7 * 8 * SMP support for BMIPS 9 */ 10 11 #include <linux/init.h> 12 #include <linux/sched.h> 13 #include <linux/sched/hotplug.h> 14 #include <linux/sched/task_stack.h> 15 #include <linux/mm.h> 16 #include <linux/delay.h> 17 #include <linux/smp.h> 18 #include <linux/interrupt.h> 19 #include <linux/spinlock.h> 20 #include <linux/cpu.h> 21 #include <linux/cpumask.h> 22 #include <linux/reboot.h> 23 #include <linux/io.h> 24 #include <linux/compiler.h> 25 #include <linux/linkage.h> 26 #include <linux/bug.h> 27 #include <linux/kernel.h> 28 #include <linux/kexec.h> 29 30 #include <asm/time.h> 31 #include <asm/pgtable.h> 32 #include <asm/processor.h> 33 #include <asm/bootinfo.h> 34 #include <asm/cacheflush.h> 35 #include <asm/tlbflush.h> 36 #include <asm/mipsregs.h> 37 #include <asm/bmips.h> 38 #include <asm/traps.h> 39 #include <asm/barrier.h> 40 #include <asm/cpu-features.h> 41 42 static int __maybe_unused max_cpus = 1; 43 44 /* these may be configured by the platform code */ 45 int bmips_smp_enabled = 1; 46 int bmips_cpu_offset; 47 cpumask_t bmips_booted_mask; 48 unsigned long bmips_tp1_irqs = IE_IRQ1; 49 50 #define RESET_FROM_KSEG0 0x80080800 51 #define RESET_FROM_KSEG1 0xa0080800 52 53 static void bmips_set_reset_vec(int cpu, u32 val); 54 55 #ifdef CONFIG_SMP 56 57 /* initial $sp, $gp - used by arch/mips/kernel/bmips_vec.S */ 58 unsigned long bmips_smp_boot_sp; 59 unsigned long bmips_smp_boot_gp; 60 61 static void bmips43xx_send_ipi_single(int cpu, unsigned int action); 62 static void bmips5000_send_ipi_single(int cpu, unsigned int action); 63 static irqreturn_t bmips43xx_ipi_interrupt(int irq, void *dev_id); 64 static irqreturn_t bmips5000_ipi_interrupt(int irq, void *dev_id); 65 66 /* SW interrupts 0,1 are used for interprocessor signaling */ 67 #define IPI0_IRQ (MIPS_CPU_IRQ_BASE + 0) 68 #define IPI1_IRQ (MIPS_CPU_IRQ_BASE + 1) 69 70 #define CPUNUM(cpu, shift) (((cpu) + bmips_cpu_offset) << (shift)) 71 #define ACTION_CLR_IPI(cpu, ipi) (0x2000 | CPUNUM(cpu, 9) | ((ipi) << 8)) 72 #define ACTION_SET_IPI(cpu, ipi) (0x3000 | CPUNUM(cpu, 9) | ((ipi) << 8)) 73 #define ACTION_BOOT_THREAD(cpu) (0x08 | CPUNUM(cpu, 0)) 74 75 static void __init bmips_smp_setup(void) 76 { 77 int i, cpu = 1, boot_cpu = 0; 78 int cpu_hw_intr; 79 80 switch (current_cpu_type()) { 81 case CPU_BMIPS4350: 82 case CPU_BMIPS4380: 83 /* arbitration priority */ 84 clear_c0_brcm_cmt_ctrl(0x30); 85 86 /* NBK and weak order flags */ 87 set_c0_brcm_config_0(0x30000); 88 89 /* Find out if we are running on TP0 or TP1 */ 90 boot_cpu = !!(read_c0_brcm_cmt_local() & (1 << 31)); 91 92 /* 93 * MIPS interrupts 0,1 (SW INT 0,1) cross over to the other 94 * thread 95 * MIPS interrupt 2 (HW INT 0) is the CPU0 L1 controller output 96 * MIPS interrupt 3 (HW INT 1) is the CPU1 L1 controller output 97 */ 98 if (boot_cpu == 0) 99 cpu_hw_intr = 0x02; 100 else 101 cpu_hw_intr = 0x1d; 102 103 change_c0_brcm_cmt_intr(0xf8018000, 104 (cpu_hw_intr << 27) | (0x03 << 15)); 105 106 /* single core, 2 threads (2 pipelines) */ 107 max_cpus = 2; 108 109 break; 110 case CPU_BMIPS5000: 111 /* enable raceless SW interrupts */ 112 set_c0_brcm_config(0x03 << 22); 113 114 /* route HW interrupt 0 to CPU0, HW interrupt 1 to CPU1 */ 115 change_c0_brcm_mode(0x1f << 27, 0x02 << 27); 116 117 /* N cores, 2 threads per core */ 118 max_cpus = (((read_c0_brcm_config() >> 6) & 0x03) + 1) << 1; 119 120 /* clear any pending SW interrupts */ 121 for (i = 0; i < max_cpus; i++) { 122 write_c0_brcm_action(ACTION_CLR_IPI(i, 0)); 123 write_c0_brcm_action(ACTION_CLR_IPI(i, 1)); 124 } 125 126 break; 127 default: 128 max_cpus = 1; 129 } 130 131 if (!bmips_smp_enabled) 132 max_cpus = 1; 133 134 /* this can be overridden by the BSP */ 135 if (!board_ebase_setup) 136 board_ebase_setup = &bmips_ebase_setup; 137 138 __cpu_number_map[boot_cpu] = 0; 139 __cpu_logical_map[0] = boot_cpu; 140 141 for (i = 0; i < max_cpus; i++) { 142 if (i != boot_cpu) { 143 __cpu_number_map[i] = cpu; 144 __cpu_logical_map[cpu] = i; 145 cpu++; 146 } 147 set_cpu_possible(i, 1); 148 set_cpu_present(i, 1); 149 } 150 } 151 152 /* 153 * IPI IRQ setup - runs on CPU0 154 */ 155 static void bmips_prepare_cpus(unsigned int max_cpus) 156 { 157 irqreturn_t (*bmips_ipi_interrupt)(int irq, void *dev_id); 158 159 switch (current_cpu_type()) { 160 case CPU_BMIPS4350: 161 case CPU_BMIPS4380: 162 bmips_ipi_interrupt = bmips43xx_ipi_interrupt; 163 break; 164 case CPU_BMIPS5000: 165 bmips_ipi_interrupt = bmips5000_ipi_interrupt; 166 break; 167 default: 168 return; 169 } 170 171 if (request_irq(IPI0_IRQ, bmips_ipi_interrupt, 172 IRQF_PERCPU | IRQF_NO_SUSPEND, "smp_ipi0", NULL)) 173 panic("Can't request IPI0 interrupt"); 174 if (request_irq(IPI1_IRQ, bmips_ipi_interrupt, 175 IRQF_PERCPU | IRQF_NO_SUSPEND, "smp_ipi1", NULL)) 176 panic("Can't request IPI1 interrupt"); 177 } 178 179 /* 180 * Tell the hardware to boot CPUx - runs on CPU0 181 */ 182 static int bmips_boot_secondary(int cpu, struct task_struct *idle) 183 { 184 bmips_smp_boot_sp = __KSTK_TOS(idle); 185 bmips_smp_boot_gp = (unsigned long)task_thread_info(idle); 186 mb(); 187 188 /* 189 * Initial boot sequence for secondary CPU: 190 * bmips_reset_nmi_vec @ a000_0000 -> 191 * bmips_smp_entry -> 192 * plat_wired_tlb_setup (cached function call; optional) -> 193 * start_secondary (cached jump) 194 * 195 * Warm restart sequence: 196 * play_dead WAIT loop -> 197 * bmips_smp_int_vec @ BMIPS_WARM_RESTART_VEC -> 198 * eret to play_dead -> 199 * bmips_secondary_reentry -> 200 * start_secondary 201 */ 202 203 pr_info("SMP: Booting CPU%d...\n", cpu); 204 205 if (cpumask_test_cpu(cpu, &bmips_booted_mask)) { 206 /* kseg1 might not exist if this CPU enabled XKS01 */ 207 bmips_set_reset_vec(cpu, RESET_FROM_KSEG0); 208 209 switch (current_cpu_type()) { 210 case CPU_BMIPS4350: 211 case CPU_BMIPS4380: 212 bmips43xx_send_ipi_single(cpu, 0); 213 break; 214 case CPU_BMIPS5000: 215 bmips5000_send_ipi_single(cpu, 0); 216 break; 217 } 218 } else { 219 bmips_set_reset_vec(cpu, RESET_FROM_KSEG1); 220 221 switch (current_cpu_type()) { 222 case CPU_BMIPS4350: 223 case CPU_BMIPS4380: 224 /* Reset slave TP1 if booting from TP0 */ 225 if (cpu_logical_map(cpu) == 1) 226 set_c0_brcm_cmt_ctrl(0x01); 227 break; 228 case CPU_BMIPS5000: 229 write_c0_brcm_action(ACTION_BOOT_THREAD(cpu)); 230 break; 231 } 232 cpumask_set_cpu(cpu, &bmips_booted_mask); 233 } 234 235 return 0; 236 } 237 238 /* 239 * Early setup - runs on secondary CPU after cache probe 240 */ 241 static void bmips_init_secondary(void) 242 { 243 switch (current_cpu_type()) { 244 case CPU_BMIPS4350: 245 case CPU_BMIPS4380: 246 clear_c0_cause(smp_processor_id() ? C_SW1 : C_SW0); 247 break; 248 case CPU_BMIPS5000: 249 write_c0_brcm_action(ACTION_CLR_IPI(smp_processor_id(), 0)); 250 cpu_set_core(¤t_cpu_data, (read_c0_brcm_config() >> 25) & 3); 251 break; 252 } 253 } 254 255 /* 256 * Late setup - runs on secondary CPU before entering the idle loop 257 */ 258 static void bmips_smp_finish(void) 259 { 260 pr_info("SMP: CPU%d is running\n", smp_processor_id()); 261 262 /* make sure there won't be a timer interrupt for a little while */ 263 write_c0_compare(read_c0_count() + mips_hpt_frequency / HZ); 264 265 irq_enable_hazard(); 266 set_c0_status(IE_SW0 | IE_SW1 | bmips_tp1_irqs | IE_IRQ5 | ST0_IE); 267 irq_enable_hazard(); 268 } 269 270 /* 271 * BMIPS5000 raceless IPIs 272 * 273 * Each CPU has two inbound SW IRQs which are independent of all other CPUs. 274 * IPI0 is used for SMP_RESCHEDULE_YOURSELF 275 * IPI1 is used for SMP_CALL_FUNCTION 276 */ 277 278 static void bmips5000_send_ipi_single(int cpu, unsigned int action) 279 { 280 write_c0_brcm_action(ACTION_SET_IPI(cpu, action == SMP_CALL_FUNCTION)); 281 } 282 283 static irqreturn_t bmips5000_ipi_interrupt(int irq, void *dev_id) 284 { 285 int action = irq - IPI0_IRQ; 286 287 write_c0_brcm_action(ACTION_CLR_IPI(smp_processor_id(), action)); 288 289 if (action == 0) 290 scheduler_ipi(); 291 else 292 generic_smp_call_function_interrupt(); 293 294 return IRQ_HANDLED; 295 } 296 297 static void bmips5000_send_ipi_mask(const struct cpumask *mask, 298 unsigned int action) 299 { 300 unsigned int i; 301 302 for_each_cpu(i, mask) 303 bmips5000_send_ipi_single(i, action); 304 } 305 306 /* 307 * BMIPS43xx racey IPIs 308 * 309 * We use one inbound SW IRQ for each CPU. 310 * 311 * A spinlock must be held in order to keep CPUx from accidentally clearing 312 * an incoming IPI when it writes CP0 CAUSE to raise an IPI on CPUy. The 313 * same spinlock is used to protect the action masks. 314 */ 315 316 static DEFINE_SPINLOCK(ipi_lock); 317 static DEFINE_PER_CPU(int, ipi_action_mask); 318 319 static void bmips43xx_send_ipi_single(int cpu, unsigned int action) 320 { 321 unsigned long flags; 322 323 spin_lock_irqsave(&ipi_lock, flags); 324 set_c0_cause(cpu ? C_SW1 : C_SW0); 325 per_cpu(ipi_action_mask, cpu) |= action; 326 irq_enable_hazard(); 327 spin_unlock_irqrestore(&ipi_lock, flags); 328 } 329 330 static irqreturn_t bmips43xx_ipi_interrupt(int irq, void *dev_id) 331 { 332 unsigned long flags; 333 int action, cpu = irq - IPI0_IRQ; 334 335 spin_lock_irqsave(&ipi_lock, flags); 336 action = __this_cpu_read(ipi_action_mask); 337 per_cpu(ipi_action_mask, cpu) = 0; 338 clear_c0_cause(cpu ? C_SW1 : C_SW0); 339 spin_unlock_irqrestore(&ipi_lock, flags); 340 341 if (action & SMP_RESCHEDULE_YOURSELF) 342 scheduler_ipi(); 343 if (action & SMP_CALL_FUNCTION) 344 generic_smp_call_function_interrupt(); 345 346 return IRQ_HANDLED; 347 } 348 349 static void bmips43xx_send_ipi_mask(const struct cpumask *mask, 350 unsigned int action) 351 { 352 unsigned int i; 353 354 for_each_cpu(i, mask) 355 bmips43xx_send_ipi_single(i, action); 356 } 357 358 #ifdef CONFIG_HOTPLUG_CPU 359 360 static int bmips_cpu_disable(void) 361 { 362 unsigned int cpu = smp_processor_id(); 363 364 if (cpu == 0) 365 return -EBUSY; 366 367 pr_info("SMP: CPU%d is offline\n", cpu); 368 369 set_cpu_online(cpu, false); 370 calculate_cpu_foreign_map(); 371 irq_cpu_offline(); 372 clear_c0_status(IE_IRQ5); 373 374 local_flush_tlb_all(); 375 local_flush_icache_range(0, ~0); 376 377 return 0; 378 } 379 380 static void bmips_cpu_die(unsigned int cpu) 381 { 382 } 383 384 void __ref play_dead(void) 385 { 386 idle_task_exit(); 387 388 /* flush data cache */ 389 _dma_cache_wback_inv(0, ~0); 390 391 /* 392 * Wakeup is on SW0 or SW1; disable everything else 393 * Use BEV !IV (BMIPS_WARM_RESTART_VEC) to avoid the regular Linux 394 * IRQ handlers; this clears ST0_IE and returns immediately. 395 */ 396 clear_c0_cause(CAUSEF_IV | C_SW0 | C_SW1); 397 change_c0_status( 398 IE_IRQ5 | bmips_tp1_irqs | IE_SW0 | IE_SW1 | ST0_IE | ST0_BEV, 399 IE_SW0 | IE_SW1 | ST0_IE | ST0_BEV); 400 irq_disable_hazard(); 401 402 /* 403 * wait for SW interrupt from bmips_boot_secondary(), then jump 404 * back to start_secondary() 405 */ 406 __asm__ __volatile__( 407 " wait\n" 408 " j bmips_secondary_reentry\n" 409 : : : "memory"); 410 } 411 412 #endif /* CONFIG_HOTPLUG_CPU */ 413 414 const struct plat_smp_ops bmips43xx_smp_ops = { 415 .smp_setup = bmips_smp_setup, 416 .prepare_cpus = bmips_prepare_cpus, 417 .boot_secondary = bmips_boot_secondary, 418 .smp_finish = bmips_smp_finish, 419 .init_secondary = bmips_init_secondary, 420 .send_ipi_single = bmips43xx_send_ipi_single, 421 .send_ipi_mask = bmips43xx_send_ipi_mask, 422 #ifdef CONFIG_HOTPLUG_CPU 423 .cpu_disable = bmips_cpu_disable, 424 .cpu_die = bmips_cpu_die, 425 #endif 426 #ifdef CONFIG_KEXEC 427 .kexec_nonboot_cpu = kexec_nonboot_cpu_jump, 428 #endif 429 }; 430 431 const struct plat_smp_ops bmips5000_smp_ops = { 432 .smp_setup = bmips_smp_setup, 433 .prepare_cpus = bmips_prepare_cpus, 434 .boot_secondary = bmips_boot_secondary, 435 .smp_finish = bmips_smp_finish, 436 .init_secondary = bmips_init_secondary, 437 .send_ipi_single = bmips5000_send_ipi_single, 438 .send_ipi_mask = bmips5000_send_ipi_mask, 439 #ifdef CONFIG_HOTPLUG_CPU 440 .cpu_disable = bmips_cpu_disable, 441 .cpu_die = bmips_cpu_die, 442 #endif 443 #ifdef CONFIG_KEXEC 444 .kexec_nonboot_cpu = kexec_nonboot_cpu_jump, 445 #endif 446 }; 447 448 #endif /* CONFIG_SMP */ 449 450 /*********************************************************************** 451 * BMIPS vector relocation 452 * This is primarily used for SMP boot, but it is applicable to some 453 * UP BMIPS systems as well. 454 ***********************************************************************/ 455 456 static void bmips_wr_vec(unsigned long dst, char *start, char *end) 457 { 458 memcpy((void *)dst, start, end - start); 459 dma_cache_wback(dst, end - start); 460 local_flush_icache_range(dst, dst + (end - start)); 461 instruction_hazard(); 462 } 463 464 static inline void bmips_nmi_handler_setup(void) 465 { 466 bmips_wr_vec(BMIPS_NMI_RESET_VEC, bmips_reset_nmi_vec, 467 bmips_reset_nmi_vec_end); 468 bmips_wr_vec(BMIPS_WARM_RESTART_VEC, bmips_smp_int_vec, 469 bmips_smp_int_vec_end); 470 } 471 472 struct reset_vec_info { 473 int cpu; 474 u32 val; 475 }; 476 477 static void bmips_set_reset_vec_remote(void *vinfo) 478 { 479 struct reset_vec_info *info = vinfo; 480 int shift = info->cpu & 0x01 ? 16 : 0; 481 u32 mask = ~(0xffff << shift), val = info->val >> 16; 482 483 preempt_disable(); 484 if (smp_processor_id() > 0) { 485 smp_call_function_single(0, &bmips_set_reset_vec_remote, 486 info, 1); 487 } else { 488 if (info->cpu & 0x02) { 489 /* BMIPS5200 "should" use mask/shift, but it's buggy */ 490 bmips_write_zscm_reg(0xa0, (val << 16) | val); 491 bmips_read_zscm_reg(0xa0); 492 } else { 493 write_c0_brcm_bootvec((read_c0_brcm_bootvec() & mask) | 494 (val << shift)); 495 } 496 } 497 preempt_enable(); 498 } 499 500 static void bmips_set_reset_vec(int cpu, u32 val) 501 { 502 struct reset_vec_info info; 503 504 if (current_cpu_type() == CPU_BMIPS5000) { 505 /* this needs to run from CPU0 (which is always online) */ 506 info.cpu = cpu; 507 info.val = val; 508 bmips_set_reset_vec_remote(&info); 509 } else { 510 void __iomem *cbr = BMIPS_GET_CBR(); 511 512 if (cpu == 0) 513 __raw_writel(val, cbr + BMIPS_RELO_VECTOR_CONTROL_0); 514 else { 515 if (current_cpu_type() != CPU_BMIPS4380) 516 return; 517 __raw_writel(val, cbr + BMIPS_RELO_VECTOR_CONTROL_1); 518 } 519 } 520 __sync(); 521 back_to_back_c0_hazard(); 522 } 523 524 void bmips_ebase_setup(void) 525 { 526 unsigned long new_ebase = ebase; 527 528 BUG_ON(ebase != CKSEG0); 529 530 switch (current_cpu_type()) { 531 case CPU_BMIPS4350: 532 /* 533 * BMIPS4350 cannot relocate the normal vectors, but it 534 * can relocate the BEV=1 vectors. So CPU1 starts up at 535 * the relocated BEV=1, IV=0 general exception vector @ 536 * 0xa000_0380. 537 * 538 * set_uncached_handler() is used here because: 539 * - CPU1 will run this from uncached space 540 * - None of the cacheflush functions are set up yet 541 */ 542 set_uncached_handler(BMIPS_WARM_RESTART_VEC - CKSEG0, 543 &bmips_smp_int_vec, 0x80); 544 __sync(); 545 return; 546 case CPU_BMIPS3300: 547 case CPU_BMIPS4380: 548 /* 549 * 0x8000_0000: reset/NMI (initially in kseg1) 550 * 0x8000_0400: normal vectors 551 */ 552 new_ebase = 0x80000400; 553 bmips_set_reset_vec(0, RESET_FROM_KSEG0); 554 break; 555 case CPU_BMIPS5000: 556 /* 557 * 0x8000_0000: reset/NMI (initially in kseg1) 558 * 0x8000_1000: normal vectors 559 */ 560 new_ebase = 0x80001000; 561 bmips_set_reset_vec(0, RESET_FROM_KSEG0); 562 write_c0_ebase(new_ebase); 563 break; 564 default: 565 return; 566 } 567 568 board_nmi_handler_setup = &bmips_nmi_handler_setup; 569 ebase = new_ebase; 570 } 571 572 asmlinkage void __weak plat_wired_tlb_setup(void) 573 { 574 /* 575 * Called when starting/restarting a secondary CPU. 576 * Kernel stacks and other important data might only be accessible 577 * once the wired entries are present. 578 */ 579 } 580 581 void bmips_cpu_setup(void) 582 { 583 void __iomem __maybe_unused *cbr = BMIPS_GET_CBR(); 584 u32 __maybe_unused cfg; 585 586 switch (current_cpu_type()) { 587 case CPU_BMIPS3300: 588 /* Set BIU to async mode */ 589 set_c0_brcm_bus_pll(BIT(22)); 590 __sync(); 591 592 /* put the BIU back in sync mode */ 593 clear_c0_brcm_bus_pll(BIT(22)); 594 595 /* clear BHTD to enable branch history table */ 596 clear_c0_brcm_reset(BIT(16)); 597 598 /* Flush and enable RAC */ 599 cfg = __raw_readl(cbr + BMIPS_RAC_CONFIG); 600 __raw_writel(cfg | 0x100, cbr + BMIPS_RAC_CONFIG); 601 __raw_readl(cbr + BMIPS_RAC_CONFIG); 602 603 cfg = __raw_readl(cbr + BMIPS_RAC_CONFIG); 604 __raw_writel(cfg | 0xf, cbr + BMIPS_RAC_CONFIG); 605 __raw_readl(cbr + BMIPS_RAC_CONFIG); 606 607 cfg = __raw_readl(cbr + BMIPS_RAC_ADDRESS_RANGE); 608 __raw_writel(cfg | 0x0fff0000, cbr + BMIPS_RAC_ADDRESS_RANGE); 609 __raw_readl(cbr + BMIPS_RAC_ADDRESS_RANGE); 610 break; 611 612 case CPU_BMIPS4380: 613 /* CBG workaround for early BMIPS4380 CPUs */ 614 switch (read_c0_prid()) { 615 case 0x2a040: 616 case 0x2a042: 617 case 0x2a044: 618 case 0x2a060: 619 cfg = __raw_readl(cbr + BMIPS_L2_CONFIG); 620 __raw_writel(cfg & ~0x07000000, cbr + BMIPS_L2_CONFIG); 621 __raw_readl(cbr + BMIPS_L2_CONFIG); 622 } 623 624 /* clear BHTD to enable branch history table */ 625 clear_c0_brcm_config_0(BIT(21)); 626 627 /* XI/ROTR enable */ 628 set_c0_brcm_config_0(BIT(23)); 629 set_c0_brcm_cmt_ctrl(BIT(15)); 630 break; 631 632 case CPU_BMIPS5000: 633 /* enable RDHWR, BRDHWR */ 634 set_c0_brcm_config(BIT(17) | BIT(21)); 635 636 /* Disable JTB */ 637 __asm__ __volatile__( 638 " .set noreorder\n" 639 " li $8, 0x5a455048\n" 640 " .word 0x4088b00f\n" /* mtc0 t0, $22, 15 */ 641 " .word 0x4008b008\n" /* mfc0 t0, $22, 8 */ 642 " li $9, 0x00008000\n" 643 " or $8, $8, $9\n" 644 " .word 0x4088b008\n" /* mtc0 t0, $22, 8 */ 645 " sync\n" 646 " li $8, 0x0\n" 647 " .word 0x4088b00f\n" /* mtc0 t0, $22, 15 */ 648 " .set reorder\n" 649 : : : "$8", "$9"); 650 651 /* XI enable */ 652 set_c0_brcm_config(BIT(27)); 653 654 /* enable MIPS32R2 ROR instruction for XI TLB handlers */ 655 __asm__ __volatile__( 656 " li $8, 0x5a455048\n" 657 " .word 0x4088b00f\n" /* mtc0 $8, $22, 15 */ 658 " nop; nop; nop\n" 659 " .word 0x4008b008\n" /* mfc0 $8, $22, 8 */ 660 " lui $9, 0x0100\n" 661 " or $8, $9\n" 662 " .word 0x4088b008\n" /* mtc0 $8, $22, 8 */ 663 : : : "$8", "$9"); 664 break; 665 } 666 } 667