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booke_machdep.c revision 1.14
      1 /*	$NetBSD: booke_machdep.c,v 1.14 2011/06/30 00:52:58 matt Exp $	*/
      2 /*-
      3  * Copyright (c) 2010, 2011 The NetBSD Foundation, Inc.
      4  * All rights reserved.
      5  *
      6  * This code is derived from software contributed to The NetBSD Foundation
      7  * by Raytheon BBN Technologies Corp and Defense Advanced Research Projects
      8  * Agency and which was developed by Matt Thomas of 3am Software Foundry.
      9  *
     10  * This material is based upon work supported by the Defense Advanced Research
     11  * Projects Agency and Space and Naval Warfare Systems Center, Pacific, under
     12  * Contract No. N66001-09-C-2073.
     13  * Approved for Public Release, Distribution Unlimited
     14  *
     15  * Redistribution and use in source and binary forms, with or without
     16  * modification, are permitted provided that the following conditions
     17  * are met:
     18  * 1. Redistributions of source code must retain the above copyright
     19  *    notice, this list of conditions and the following disclaimer.
     20  * 2. Redistributions in binary form must reproduce the above copyright
     21  *    notice, this list of conditions and the following disclaimer in the
     22  *    documentation and/or other materials provided with the distribution.
     23  *
     24  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     25  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     26  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     27  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     28  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     29  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     30  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     31  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     32  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     33  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     34  * POSSIBILITY OF SUCH DAMAGE.
     35  */
     36 
     37 #define	__INTR_PRIVATE
     38 #define	_POWERPC_BUS_DMA_PRIVATE
     39 
     40 #include <sys/cdefs.h>
     41 __KERNEL_RCSID(0, "$NetBSD: booke_machdep.c,v 1.14 2011/06/30 00:52:58 matt Exp $");
     42 
     43 #include "opt_modular.h"
     44 
     45 #include <sys/param.h>
     46 #include <sys/cpu.h>
     47 #include <sys/device.h>
     48 #include <sys/intr.h>
     49 #include <sys/mount.h>
     50 #include <sys/msgbuf.h>
     51 #include <sys/kernel.h>
     52 #include <sys/reboot.h>
     53 #include <sys/bus.h>
     54 
     55 #include <uvm/uvm_extern.h>
     56 
     57 #include <powerpc/cpuset.h>
     58 #include <powerpc/pcb.h>
     59 #include <powerpc/spr.h>
     60 #include <powerpc/booke/spr.h>
     61 #include <powerpc/booke/cpuvar.h>
     62 
     63 /*
     64  * Global variables used here and there
     65  */
     66 paddr_t msgbuf_paddr;
     67 psize_t pmemsize;
     68 struct vm_map *phys_map;
     69 
     70 #ifdef MODULAR
     71 register_t cpu_psluserset = PSL_USERSET;
     72 register_t cpu_pslusermod = PSL_USERMOD;
     73 register_t cpu_pslusermask = PSL_USERMASK;
     74 #endif
     75 
     76 static bus_addr_t booke_dma_phys_to_bus_mem(bus_dma_tag_t, bus_addr_t);
     77 static bus_addr_t booke_dma_bus_mem_to_phys(bus_dma_tag_t, bus_addr_t);
     78 
     79 
     80 struct powerpc_bus_dma_tag booke_bus_dma_tag = {
     81 	._dmamap_create = _bus_dmamap_create,
     82 	._dmamap_destroy = _bus_dmamap_destroy,
     83 	._dmamap_load = _bus_dmamap_load,
     84 	._dmamap_load_mbuf = _bus_dmamap_load_mbuf,
     85 	._dmamap_load_uio = _bus_dmamap_load_uio,
     86 	._dmamap_load_raw = _bus_dmamap_load_raw,
     87 	._dmamap_unload = _bus_dmamap_unload,
     88 	._dmamap_sync = _bus_dmamap_sync,
     89 	._dmamem_alloc = _bus_dmamem_alloc,
     90 	._dmamem_free = _bus_dmamem_free,
     91 	._dmamem_map = _bus_dmamem_map,
     92 	._dmamem_unmap = _bus_dmamem_unmap,
     93 	._dmamem_mmap = _bus_dmamem_mmap,
     94 	._dma_phys_to_bus_mem = booke_dma_phys_to_bus_mem,
     95 	._dma_bus_mem_to_phys = booke_dma_bus_mem_to_phys,
     96 };
     97 
     98 static bus_addr_t
     99 booke_dma_phys_to_bus_mem(bus_dma_tag_t t, bus_addr_t a)
    100 {
    101 	return a;
    102 }
    103 
    104 static bus_addr_t
    105 booke_dma_bus_mem_to_phys(bus_dma_tag_t t, bus_addr_t a)
    106 {
    107 	return a;
    108 }
    109 
    110 struct cpu_md_ops cpu_md_ops;
    111 
    112 struct cpu_softc cpu_softc[] = {
    113 	[0] = {
    114 		.cpu_ci = &cpu_info[0],
    115 	},
    116 #ifdef MULTIPROCESSOR
    117 	[CPU_MAXNUM-1] = {
    118 		.cpu_ci = &cpu_info[CPU_MAXNUM-1],
    119 	},
    120 #endif
    121 };
    122 struct cpu_info cpu_info[] = {
    123 	[0] = {
    124 		.ci_curlwp = &lwp0,
    125 		.ci_tlb_info = &pmap_tlb0_info,
    126 		.ci_softc = &cpu_softc[0],
    127 		.ci_cpl = IPL_HIGH,
    128 		.ci_idepth = -1,
    129 	},
    130 #ifdef MULTIPROCESSOR
    131 	[CPU_MAXNUM-1] = {
    132 		.ci_curlwp = NULL,
    133 		.ci_tlb_info = &pmap_tlb0_info,
    134 		.ci_softc = &cpu_softc[CPU_MAXNUM-1],
    135 		.ci_cpl = IPL_HIGH,
    136 		.ci_idepth = -1,
    137 	},
    138 #endif
    139 };
    140 __CTASSERT(__arraycount(cpu_info) == __arraycount(cpu_softc));
    141 
    142 /*
    143  * This should probably be in autoconf!				XXX
    144  */
    145 char cpu_model[80];
    146 char machine[] = MACHINE;		/* from <machine/param.h> */
    147 char machine_arch[] = MACHINE_ARCH;	/* from <machine/param.h> */
    148 
    149 char bootpath[256];
    150 
    151 #if NKSYMS || defined(DDB) || defined(MODULAR)
    152 void *startsym, *endsym;
    153 #endif
    154 
    155 #if defined(MULTIPROCESSOR)
    156 volatile struct cpu_hatch_data cpu_hatch_data __cacheline_aligned;
    157 #endif
    158 
    159 int fake_mapiodev = 1;
    160 
    161 void
    162 booke_cpu_startup(const char *model)
    163 {
    164 	vaddr_t 	minaddr, maxaddr;
    165 	char 		pbuf[9];
    166 
    167 	strlcpy(cpu_model, model, sizeof(cpu_model));
    168 
    169 	printf("%s%s", copyright, version);
    170 
    171 	format_bytes(pbuf, sizeof(pbuf), ctob((uint64_t)physmem));
    172 	printf("total memory = %s\n", pbuf);
    173 
    174 	minaddr = 0;
    175 	/*
    176 	 * Allocate a submap for physio
    177 	 */
    178 	phys_map = uvm_km_suballoc(kernel_map, &minaddr, &maxaddr,
    179 				 VM_PHYS_SIZE, 0, false, NULL);
    180 
    181 	/*
    182 	 * No need to allocate an mbuf cluster submap.  Mbuf clusters
    183 	 * are allocated via the pool allocator, and we use direct-mapped
    184 	 * pool pages.
    185 	 */
    186 
    187 	format_bytes(pbuf, sizeof(pbuf), ptoa(uvmexp.free));
    188 	printf("avail memory = %s\n", pbuf);
    189 
    190 	/*
    191 	 * Register the tlb's evcnts
    192 	 */
    193 	pmap_tlb_info_evcnt_attach(curcpu()->ci_tlb_info);
    194 
    195 	/*
    196 	 * Set up the board properties database.
    197 	 */
    198 	board_info_init();
    199 
    200 	/*
    201 	 * Now that we have VM, malloc()s are OK in bus_space.
    202 	 */
    203 	bus_space_mallocok();
    204 	fake_mapiodev = 0;
    205 
    206 #ifdef MULTIPROCESSOR
    207 	for (size_t i = 1; i < __arraycount(cpu_info); i++) {
    208 		struct cpu_info * const ci = &cpu_info[i];
    209 		struct cpu_softc * const cpu = &cpu_softc[i];
    210 		cpu->cpu_ci = ci;
    211 		cpu->cpu_bst = cpu_softc[0].cpu_bst;
    212 		cpu->cpu_le_bst = cpu_softc[0].cpu_le_bst;
    213 		cpu->cpu_bsh = cpu_softc[0].cpu_bsh;
    214 		cpu->cpu_highmem = cpu_softc[0].cpu_highmem;
    215 		ci->ci_softc = cpu;
    216 		ci->ci_tlb_info = &pmap_tlb0_info;
    217 		ci->ci_cpl = IPL_HIGH;
    218 		ci->ci_idepth = -1;
    219 		ci->ci_pmap_kern_segtab = curcpu()->ci_pmap_kern_segtab;
    220 	}
    221 #endif /* MULTIPROCESSOR */
    222 }
    223 
    224 static void
    225 dumpsys(void)
    226 {
    227 
    228 	printf("dumpsys: TBD\n");
    229 }
    230 
    231 /*
    232  * Halt or reboot the machine after syncing/dumping according to howto.
    233  */
    234 void
    235 cpu_reboot(int howto, char *what)
    236 {
    237 	static int syncing;
    238 	static char str[256];
    239 	char *ap = str, *ap1 = ap;
    240 
    241 	boothowto = howto;
    242 	if (!cold && !(howto & RB_NOSYNC) && !syncing) {
    243 		syncing = 1;
    244 		vfs_shutdown();		/* sync */
    245 		resettodr();		/* set wall clock */
    246 	}
    247 
    248 	splhigh();
    249 
    250 	if (!cold && (howto & RB_DUMP))
    251 		dumpsys();
    252 
    253 	doshutdownhooks();
    254 
    255 	pmf_system_shutdown(boothowto);
    256 
    257 	if ((howto & RB_POWERDOWN) == RB_POWERDOWN) {
    258 	  /* Power off here if we know how...*/
    259 	}
    260 
    261 	if (howto & RB_HALT) {
    262 		printf("halted\n\n");
    263 
    264 		goto reboot;	/* XXX for now... */
    265 
    266 #ifdef DDB
    267 		printf("dropping to debugger\n");
    268 		while(1)
    269 			Debugger();
    270 #endif
    271 	}
    272 
    273 	printf("rebooting\n\n");
    274 	if (what && *what) {
    275 		if (strlen(what) > sizeof str - 5)
    276 			printf("boot string too large, ignored\n");
    277 		else {
    278 			strcpy(str, what);
    279 			ap1 = ap = str + strlen(str);
    280 			*ap++ = ' ';
    281 		}
    282 	}
    283 	*ap++ = '-';
    284 	if (howto & RB_SINGLE)
    285 		*ap++ = 's';
    286 	if (howto & RB_KDB)
    287 		*ap++ = 'd';
    288 	*ap++ = 0;
    289 	if (ap[-2] == '-')
    290 		*ap1 = 0;
    291 
    292 	/* flush cache for msgbuf */
    293 	dcache_wb(msgbuf_paddr, round_page(MSGBUFSIZE));
    294 
    295  reboot:
    296 	__asm volatile("msync; isync");
    297 	(*cpu_md_ops.md_cpu_reset)();
    298 
    299 	printf("%s: md_cpu_reset() failed!\n", __func__);
    300 #ifdef DDB
    301 	for (;;)
    302 		Debugger();
    303 #else
    304 	for (;;)
    305 		/* nothing */;
    306 #endif
    307 }
    308 
    309 /*
    310  * mapiodev:
    311  *
    312  * 	Allocate vm space and mapin the I/O address. Use reserved TLB
    313  * 	mapping if one is found.
    314  */
    315 void *
    316 mapiodev(paddr_t pa, psize_t len, bool prefetchable)
    317 {
    318 	const vsize_t off = pa & PAGE_MASK;
    319 
    320 	/*
    321 	 * See if we have reserved TLB entry for the pa. This needs to be
    322 	 * true for console as we can't use uvm during early bootstrap.
    323 	 */
    324 	void * const p = tlb_mapiodev(pa, len, prefetchable);
    325 	if (p != NULL)
    326 		return p;
    327 
    328 	if (fake_mapiodev)
    329 		panic("mapiodev: no TLB entry reserved for %llx+%llx",
    330 		    (long long)pa, (long long)len);
    331 
    332 	pa = trunc_page(pa);
    333 	len = round_page(off + len);
    334 	vaddr_t va = uvm_km_alloc(kernel_map, len, 0, UVM_KMF_VAONLY);
    335 
    336 	if (va == 0)
    337 		return NULL;
    338 
    339 	for (va += len, pa += len; len > 0; len -= PAGE_SIZE) {
    340 		va -= PAGE_SIZE;
    341 		pa -= PAGE_SIZE;
    342 		pmap_kenter_pa(va, pa, VM_PROT_READ|VM_PROT_WRITE,
    343 		    prefetchable ? 0 : PMAP_NOCACHE);
    344 	}
    345 	pmap_update(pmap_kernel());
    346 	return (void *)(va + off);
    347 }
    348 
    349 void
    350 unmapiodev(vaddr_t va, vsize_t len)
    351 {
    352 	/* Nothing to do for reserved (ie. not uvm_km_alloc'd) mappings. */
    353 	if (va < VM_MIN_KERNEL_ADDRESS || va > VM_MAX_KERNEL_ADDRESS) {
    354 		tlb_unmapiodev(va, len);
    355 		return;
    356 	}
    357 
    358 	len = round_page((va & PAGE_MASK) + len);
    359 	va = trunc_page(va);
    360 
    361 	pmap_kremove(va, len);
    362 	uvm_km_free(kernel_map, va, len, UVM_KMF_VAONLY);
    363 }
    364 
    365 void
    366 cpu_evcnt_attach(struct cpu_info *ci)
    367 {
    368 	struct cpu_softc * const cpu = ci->ci_softc;
    369 	const char * const xname = ci->ci_data.cpu_name;
    370 
    371 	evcnt_attach_dynamic_nozero(&ci->ci_ev_clock, EVCNT_TYPE_INTR,
    372 		NULL, xname, "clock");
    373 	evcnt_attach_dynamic_nozero(&cpu->cpu_ev_late_clock, EVCNT_TYPE_INTR,
    374 		NULL, xname, "late clock");
    375 	evcnt_attach_dynamic_nozero(&cpu->cpu_ev_exec_trap_sync, EVCNT_TYPE_TRAP,
    376 		NULL, xname, "exec pages synced (trap)");
    377 	evcnt_attach_dynamic_nozero(&ci->ci_ev_traps, EVCNT_TYPE_TRAP,
    378 		NULL, xname, "traps");
    379 	evcnt_attach_dynamic_nozero(&ci->ci_ev_kdsi, EVCNT_TYPE_TRAP,
    380 		&ci->ci_ev_traps, xname, "kernel DSI traps");
    381 	evcnt_attach_dynamic_nozero(&ci->ci_ev_udsi, EVCNT_TYPE_TRAP,
    382 		&ci->ci_ev_traps, xname, "user DSI traps");
    383 	evcnt_attach_dynamic_nozero(&ci->ci_ev_udsi_fatal, EVCNT_TYPE_TRAP,
    384 		&ci->ci_ev_udsi, xname, "user DSI failures");
    385 	evcnt_attach_dynamic_nozero(&ci->ci_ev_kisi, EVCNT_TYPE_TRAP,
    386 		&ci->ci_ev_traps, xname, "kernel ISI traps");
    387 	evcnt_attach_dynamic_nozero(&ci->ci_ev_isi, EVCNT_TYPE_TRAP,
    388 		&ci->ci_ev_traps, xname, "user ISI traps");
    389 	evcnt_attach_dynamic_nozero(&ci->ci_ev_isi_fatal, EVCNT_TYPE_TRAP,
    390 		&ci->ci_ev_isi, xname, "user ISI failures");
    391 	evcnt_attach_dynamic_nozero(&ci->ci_ev_scalls, EVCNT_TYPE_TRAP,
    392 		&ci->ci_ev_traps, xname, "system call traps");
    393 	evcnt_attach_dynamic_nozero(&ci->ci_ev_pgm, EVCNT_TYPE_TRAP,
    394 		&ci->ci_ev_traps, xname, "PGM traps");
    395 	evcnt_attach_dynamic_nozero(&ci->ci_ev_debug, EVCNT_TYPE_TRAP,
    396 		&ci->ci_ev_traps, xname, "debug traps");
    397 	evcnt_attach_dynamic_nozero(&ci->ci_ev_fpu, EVCNT_TYPE_TRAP,
    398 		&ci->ci_ev_traps, xname, "FPU unavailable traps");
    399 	evcnt_attach_dynamic_nozero(&ci->ci_ev_fpusw, EVCNT_TYPE_MISC,
    400 		&ci->ci_ev_fpu, xname, "FPU context switches");
    401 	evcnt_attach_dynamic_nozero(&ci->ci_ev_ali, EVCNT_TYPE_TRAP,
    402 		&ci->ci_ev_traps, xname, "user alignment traps");
    403 	evcnt_attach_dynamic_nozero(&ci->ci_ev_ali_fatal, EVCNT_TYPE_TRAP,
    404 		&ci->ci_ev_ali, xname, "user alignment traps");
    405 	evcnt_attach_dynamic_nozero(&ci->ci_ev_umchk, EVCNT_TYPE_TRAP,
    406 		&ci->ci_ev_umchk, xname, "user MCHK failures");
    407 	evcnt_attach_dynamic_nozero(&ci->ci_ev_vec, EVCNT_TYPE_TRAP,
    408 		&ci->ci_ev_traps, xname, "SPE unavailable");
    409 	evcnt_attach_dynamic_nozero(&ci->ci_ev_vecsw, EVCNT_TYPE_MISC,
    410 	    &ci->ci_ev_vec, xname, "SPE context switches");
    411 	evcnt_attach_dynamic_nozero(&ci->ci_ev_ipi, EVCNT_TYPE_INTR,
    412 		NULL, xname, "IPIs");
    413 	evcnt_attach_dynamic_nozero(&ci->ci_ev_tlbmiss_soft, EVCNT_TYPE_TRAP,
    414 		&ci->ci_ev_traps, xname, "soft tlb misses");
    415 	evcnt_attach_dynamic_nozero(&ci->ci_ev_dtlbmiss_hard, EVCNT_TYPE_TRAP,
    416 		&ci->ci_ev_traps, xname, "data tlb misses");
    417 	evcnt_attach_dynamic_nozero(&ci->ci_ev_itlbmiss_hard, EVCNT_TYPE_TRAP,
    418 		&ci->ci_ev_traps, xname, "inst tlb misses");
    419 }
    420 
    421 #ifdef MULTIPROCESSOR
    422 register_t
    423 cpu_hatch(void)
    424 {
    425 	volatile struct cpuset_info * const csi = &cpuset_info;
    426 	const size_t id = cpu_number();
    427 
    428 	/*
    429 	 * We've hatched so tell the spinup code.
    430 	 */
    431 	CPUSET_ADD(csi->cpus_hatched, id);
    432 
    433 	/*
    434 	 * Loop until running bit for this cpu is set.
    435 	 */
    436 	while (!CPUSET_HAS_P(csi->cpus_running, id)) {
    437 		continue;
    438 	}
    439 
    440 	/*
    441 	 * Now that we are active, start the clocks.
    442 	 */
    443 	cpu_initclocks();
    444 
    445 	/*
    446 	 * Return sp of the idlelwp.  Which we should be already using but ...
    447 	 */
    448 	return curcpu()->ci_curpcb->pcb_sp;
    449 }
    450 
    451 void
    452 cpu_boot_secondary_processors(void)
    453 {
    454 	volatile struct cpuset_info * const csi = &cpuset_info;
    455 	CPU_INFO_ITERATOR cii;
    456 	struct cpu_info *ci;
    457 	__cpuset_t running = CPUSET_NULLSET;
    458 
    459 	for (CPU_INFO_FOREACH(cii, ci)) {
    460 		/*
    461 		 * Skip this CPU if it didn't sucessfully hatch.
    462 		 */
    463 		if (! CPUSET_HAS_P(csi->cpus_hatched, cpu_index(ci)))
    464 			continue;
    465 
    466 		KASSERT(!CPU_IS_PRIMARY(ci));
    467 		KASSERT(ci->ci_data.cpu_idlelwp);
    468 
    469 		CPUSET_ADD(running, cpu_index(ci));
    470 	}
    471 	KASSERT(CPUSET_EQUAL_P(csi->cpus_hatched, running));
    472 	if (!CPUSET_EMPTY_P(running)) {
    473 		CPUSET_ADDSET(csi->cpus_running, running);
    474 	}
    475 }
    476 #endif
    477 
    478 uint32_t
    479 cpu_read_4(bus_addr_t a)
    480 {
    481 	struct cpu_softc * const cpu = curcpu()->ci_softc;
    482 //	printf(" %s(%p, %x, %x)", __func__, cpu->cpu_bst, cpu->cpu_bsh, a);
    483 	return bus_space_read_4(cpu->cpu_bst, cpu->cpu_bsh, a);
    484 }
    485 
    486 uint8_t
    487 cpu_read_1(bus_addr_t a)
    488 {
    489 	struct cpu_softc * const cpu = curcpu()->ci_softc;
    490 //	printf(" %s(%p, %x, %x)", __func__, cpu->cpu_bst, cpu->cpu_bsh, a);
    491 	return bus_space_read_1(cpu->cpu_bst, cpu->cpu_bsh, a);
    492 }
    493 
    494 void
    495 cpu_write_4(bus_addr_t a, uint32_t v)
    496 {
    497 	struct cpu_softc * const cpu = curcpu()->ci_softc;
    498 	bus_space_write_4(cpu->cpu_bst, cpu->cpu_bsh, a, v);
    499 }
    500 
    501 void
    502 cpu_write_1(bus_addr_t a, uint8_t v)
    503 {
    504 	struct cpu_softc * const cpu = curcpu()->ci_softc;
    505 	bus_space_write_1(cpu->cpu_bst, cpu->cpu_bsh, a, v);
    506 }
    507 
    508 void
    509 booke_sstep(struct trapframe *tf)
    510 {
    511 	KASSERT(tf->tf_srr1 & PSL_DE);
    512 	const uint32_t insn = ufetch_32((const void *)tf->tf_srr0);
    513 	register_t dbcr0 = DBCR0_IAC1 | DBCR0_IDM;
    514 	register_t dbcr1 = DBCR1_IAC1US_USER | DBCR1_IAC1ER_DS1;
    515 	if ((insn >> 28) == 4) {
    516 		uint32_t iac2 = 0;
    517 		if ((insn >> 26) == 0x12) {
    518 			const int32_t off = (((int32_t)insn << 6) >> 6) & ~3;
    519 			iac2 = ((insn & 2) ? 0 : tf->tf_srr0) + off;
    520 			dbcr0 |= DBCR0_IAC2;
    521 		} else if ((insn >> 26) == 0x10) {
    522 			const int16_t off = insn & ~3;
    523 			iac2 = ((insn & 2) ? 0 : tf->tf_srr0) + off;
    524 			dbcr0 |= DBCR0_IAC2;
    525 		} else if ((insn & 0xfc00ffde) == 0x4c000420) {
    526 			iac2 = tf->tf_ctr;
    527 			dbcr0 |= DBCR0_IAC2;
    528 		} else if ((insn & 0xfc00ffde) == 0x4c000020) {
    529 			iac2 = tf->tf_lr;
    530 			dbcr0 |= DBCR0_IAC2;
    531 		}
    532 		if (dbcr0 & DBCR0_IAC2) {
    533 			dbcr1 |= DBCR1_IAC2US_USER | DBCR1_IAC2ER_DS1;
    534 			mtspr(SPR_IAC2, iac2);
    535 		}
    536 	}
    537 	mtspr(SPR_IAC1, tf->tf_srr0 + 4);
    538 	mtspr(SPR_DBCR1, dbcr1);
    539 	mtspr(SPR_DBCR0, dbcr0);
    540 }
    541