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trap.c revision 1.33
      1 /*	$NetBSD: trap.c,v 1.33 2006/05/14 21:56:32 elad Exp $	*/
      2 
      3 /*
      4  * Copyright 2001 Wasabi Systems, Inc.
      5  * All rights reserved.
      6  *
      7  * Written by Eduardo Horvath and Simon Burge for Wasabi Systems, Inc.
      8  *
      9  * Redistribution and use in source and binary forms, with or without
     10  * modification, are permitted provided that the following conditions
     11  * are met:
     12  * 1. Redistributions of source code must retain the above copyright
     13  *    notice, this list of conditions and the following disclaimer.
     14  * 2. Redistributions in binary form must reproduce the above copyright
     15  *    notice, this list of conditions and the following disclaimer in the
     16  *    documentation and/or other materials provided with the distribution.
     17  * 3. All advertising materials mentioning features or use of this software
     18  *    must display the following acknowledgement:
     19  *      This product includes software developed for the NetBSD Project by
     20  *      Wasabi Systems, Inc.
     21  * 4. The name of Wasabi Systems, Inc. may not be used to endorse
     22  *    or promote products derived from this software without specific prior
     23  *    written permission.
     24  *
     25  * THIS SOFTWARE IS PROVIDED BY WASABI SYSTEMS, INC. ``AS IS'' AND
     26  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     27  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     28  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL WASABI SYSTEMS, INC
     29  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     30  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     31  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     32  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     33  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     34  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     35  * POSSIBILITY OF SUCH DAMAGE.
     36  */
     37 
     38 /*
     39  * Copyright (C) 1995, 1996 Wolfgang Solfrank.
     40  * Copyright (C) 1995, 1996 TooLs GmbH.
     41  * All rights reserved.
     42  *
     43  * Redistribution and use in source and binary forms, with or without
     44  * modification, are permitted provided that the following conditions
     45  * are met:
     46  * 1. Redistributions of source code must retain the above copyright
     47  *    notice, this list of conditions and the following disclaimer.
     48  * 2. Redistributions in binary form must reproduce the above copyright
     49  *    notice, this list of conditions and the following disclaimer in the
     50  *    documentation and/or other materials provided with the distribution.
     51  * 3. All advertising materials mentioning features or use of this software
     52  *    must display the following acknowledgement:
     53  *	This product includes software developed by TooLs GmbH.
     54  * 4. The name of TooLs GmbH may not be used to endorse or promote products
     55  *    derived from this software without specific prior written permission.
     56  *
     57  * THIS SOFTWARE IS PROVIDED BY TOOLS GMBH ``AS IS'' AND ANY EXPRESS OR
     58  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
     59  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
     60  * IN NO EVENT SHALL TOOLS GMBH BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     61  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
     62  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
     63  * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
     64  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
     65  * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
     66  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     67  */
     68 
     69 #include <sys/cdefs.h>
     70 __KERNEL_RCSID(0, "$NetBSD: trap.c,v 1.33 2006/05/14 21:56:32 elad Exp $");
     71 
     72 #include "opt_altivec.h"
     73 #include "opt_ddb.h"
     74 
     75 #include <sys/param.h>
     76 #include <sys/proc.h>
     77 #include <sys/reboot.h>
     78 #include <sys/syscall.h>
     79 #include <sys/systm.h>
     80 #include <sys/user.h>
     81 #include <sys/pool.h>
     82 #include <sys/sa.h>
     83 #include <sys/savar.h>
     84 #include <sys/userret.h>
     85 
     86 #include <uvm/uvm_extern.h>
     87 
     88 #include <dev/cons.h>
     89 
     90 #include <machine/cpu.h>
     91 #include <machine/db_machdep.h>
     92 #include <machine/fpu.h>
     93 #include <machine/frame.h>
     94 #include <machine/pcb.h>
     95 #include <machine/psl.h>
     96 #include <machine/trap.h>
     97 
     98 #include <powerpc/spr.h>
     99 #include <powerpc/ibm4xx/pmap.h>
    100 #include <powerpc/ibm4xx/tlb.h>
    101 #include <powerpc/fpu/fpu_extern.h>
    102 
    103 /* These definitions should probably be somewhere else			XXX */
    104 #define	FIRSTARG	3		/* first argument is in reg 3 */
    105 #define	NARGREG		8		/* 8 args are in registers */
    106 #define	MOREARGS(sp)	((caddr_t)((int)(sp) + 8)) /* more args go here */
    107 
    108 static int fix_unaligned __P((struct lwp *l, struct trapframe *frame));
    109 
    110 void trap __P((struct trapframe *));	/* Called from locore / trap_subr */
    111 /* Why are these not defined in a header? */
    112 int badaddr __P((void *, size_t));
    113 int badaddr_read __P((void *, size_t, int *));
    114 int ctx_setup __P((int, int));
    115 
    116 #ifdef DEBUG
    117 #define TDB_ALL	0x1
    118 int trapdebug = /* TDB_ALL */ 0;
    119 #define	DBPRINTF(x, y)	if (trapdebug & (x)) printf y
    120 #else
    121 #define DBPRINTF(x, y)
    122 #endif
    123 
    124 void
    125 trap(struct trapframe *frame)
    126 {
    127 	struct lwp *l = curlwp;
    128 	struct proc *p = l ? l->l_proc : NULL;
    129 	int type = frame->exc;
    130 	int ftype, rv;
    131 	ksiginfo_t ksi;
    132 
    133 	KASSERT(l == 0 || (l->l_stat == LSONPROC));
    134 
    135 	if (frame->srr1 & PSL_PR)
    136 		type |= EXC_USER;
    137 
    138 	ftype = VM_PROT_READ;
    139 
    140 	DBPRINTF(TDB_ALL, ("trap(%x) at %lx from frame %p &frame %p\n",
    141 	    type, frame->srr0, frame, &frame));
    142 
    143 	switch (type) {
    144 	case EXC_DEBUG|EXC_USER:
    145 		{
    146 			int srr2, srr3;
    147 
    148 			__asm volatile("mfspr %0,0x3f0" :
    149 			    "=r" (rv), "=r" (srr2), "=r" (srr3) :);
    150 			printf("debug reg is %x srr2 %x srr3 %x\n", rv, srr2,
    151 			    srr3);
    152 			/* XXX fall through or break here?! */
    153 		}
    154 		/*
    155 		 * DEBUG intr -- probably single-step.
    156 		 */
    157 	case EXC_TRC|EXC_USER:
    158 		frame->srr1 &= ~PSL_SE;
    159 		KSI_INIT_TRAP(&ksi);
    160 		ksi.ksi_signo = SIGTRAP;
    161 		ksi.ksi_trap = EXC_TRC;
    162 		ksi.ksi_addr = (void *)frame->srr0;
    163 		KERNEL_PROC_LOCK(l);
    164 		trapsignal(l, &ksi);
    165 		KERNEL_PROC_UNLOCK(l);
    166 		break;
    167 
    168 	/*
    169 	 * If we could not find and install appropriate TLB entry, fall through.
    170 	 */
    171 
    172 	case EXC_DSI:
    173 		/* FALLTHROUGH */
    174 	case EXC_DTMISS:
    175 		{
    176 			struct vm_map *map;
    177 			vaddr_t va;
    178 			struct faultbuf *fb = NULL;
    179 
    180 			KERNEL_LOCK(LK_CANRECURSE|LK_EXCLUSIVE);
    181 			va = frame->dar;
    182 			if (frame->tf_xtra[TF_PID] == KERNEL_PID) {
    183 				map = kernel_map;
    184 			} else {
    185 				map = &p->p_vmspace->vm_map;
    186 				if (l->l_flag & L_SA) {
    187 					l->l_savp->savp_faultaddr = va;
    188 					l->l_flag |= L_SA_PAGEFAULT;
    189 				}
    190 			}
    191 
    192 			if (frame->tf_xtra[TF_ESR] & (ESR_DST|ESR_DIZ))
    193 				ftype = VM_PROT_WRITE;
    194 
    195 			DBPRINTF(TDB_ALL,
    196 			    ("trap(EXC_DSI) at %lx %s fault on %p esr %x\n",
    197 			    frame->srr0,
    198 			    (ftype & VM_PROT_WRITE) ? "write" : "read",
    199 			    (void *)va, frame->tf_xtra[TF_ESR]));
    200 			rv = uvm_fault(map, trunc_page(va), ftype);
    201 			KERNEL_UNLOCK();
    202 			if (map != kernel_map)
    203 				l->l_flag &= ~L_SA_PAGEFAULT;
    204 			if (rv == 0)
    205 				goto done;
    206 			if ((fb = l->l_addr->u_pcb.pcb_onfault) != NULL) {
    207 				frame->tf_xtra[TF_PID] = KERNEL_PID;
    208 				frame->srr0 = fb->fb_pc;
    209 				frame->srr1 |= PSL_IR; /* Re-enable IMMU */
    210 				frame->fixreg[1] = fb->fb_sp;
    211 				frame->fixreg[2] = fb->fb_r2;
    212 				frame->fixreg[3] = 1; /* Return TRUE */
    213 				frame->cr = fb->fb_cr;
    214 				memcpy(&frame->fixreg[13], fb->fb_fixreg,
    215 				    sizeof(fb->fb_fixreg));
    216 				goto done;
    217 			}
    218 		}
    219 		goto brain_damage;
    220 
    221 	case EXC_DSI|EXC_USER:
    222 		/* FALLTHROUGH */
    223 	case EXC_DTMISS|EXC_USER:
    224 		KERNEL_PROC_LOCK(l);
    225 
    226 		if (frame->tf_xtra[TF_ESR] & (ESR_DST|ESR_DIZ))
    227 			ftype = VM_PROT_WRITE;
    228 
    229 		DBPRINTF(TDB_ALL,
    230 		    ("trap(EXC_DSI|EXC_USER) at %lx %s fault on %lx %x\n",
    231 		    frame->srr0, (ftype & VM_PROT_WRITE) ? "write" : "read",
    232 		    frame->dar, frame->tf_xtra[TF_ESR]));
    233 		KASSERT(l == curlwp && (l->l_stat == LSONPROC));
    234 		if (l->l_flag & L_SA) {
    235 			l->l_savp->savp_faultaddr = (vaddr_t)frame->dar;
    236 			l->l_flag |= L_SA_PAGEFAULT;
    237 		}
    238 		rv = uvm_fault(&p->p_vmspace->vm_map, trunc_page(frame->dar),
    239 		    ftype);
    240 		if (rv == 0) {
    241 			l->l_flag &= ~L_SA_PAGEFAULT;
    242 			KERNEL_PROC_UNLOCK(l);
    243 			break;
    244 		}
    245 		KSI_INIT_TRAP(&ksi);
    246 		ksi.ksi_signo = SIGSEGV;
    247 		ksi.ksi_trap = EXC_DSI;
    248 		ksi.ksi_addr = (void *)frame->dar;
    249 		if (rv == ENOMEM) {
    250 			printf("UVM: pid %d (%s) lid %d, uid %d killed: "
    251 			    "out of swap\n",
    252 			    p->p_pid, p->p_comm, l->l_lid,
    253 			    p->p_cred ?
    254 			    kauth_cred_geteuid(p->p_cred) : -1);
    255 			ksi.ksi_signo = SIGKILL;
    256 		}
    257 		trapsignal(l, &ksi);
    258 		l->l_flag &= ~L_SA_PAGEFAULT;
    259 		KERNEL_PROC_UNLOCK(l);
    260 		break;
    261 
    262 	case EXC_ITMISS|EXC_USER:
    263 	case EXC_ISI|EXC_USER:
    264 		KERNEL_PROC_LOCK(l);
    265 		if (l->l_flag & L_SA) {
    266 			l->l_savp->savp_faultaddr = (vaddr_t)frame->srr0;
    267 			l->l_flag |= L_SA_PAGEFAULT;
    268 		}
    269 		ftype = VM_PROT_EXECUTE;
    270 		DBPRINTF(TDB_ALL,
    271 		    ("trap(EXC_ISI|EXC_USER) at %lx execute fault tf %p\n",
    272 		    frame->srr0, frame));
    273 		rv = uvm_fault(&p->p_vmspace->vm_map, trunc_page(frame->srr0),
    274 		    ftype);
    275 		if (rv == 0) {
    276 			l->l_flag &= ~L_SA_PAGEFAULT;
    277 			KERNEL_PROC_UNLOCK(l);
    278 			break;
    279 		}
    280 		KSI_INIT_TRAP(&ksi);
    281 		ksi.ksi_signo = SIGSEGV;
    282 		ksi.ksi_trap = EXC_ISI;
    283 		ksi.ksi_addr = (void *)frame->srr0;
    284 		ksi.ksi_code = (rv == EACCES ? SEGV_ACCERR : SEGV_MAPERR);
    285 		trapsignal(l, &ksi);
    286 		l->l_flag &= ~L_SA_PAGEFAULT;
    287 		KERNEL_PROC_UNLOCK(l);
    288 		break;
    289 
    290 	case EXC_AST|EXC_USER:
    291 		curcpu()->ci_astpending = 0;	/* we are about to do it */
    292 		KERNEL_PROC_LOCK(l);
    293 		uvmexp.softs++;
    294 		if (p->p_flag & P_OWEUPC) {
    295 			p->p_flag &= ~P_OWEUPC;
    296 			ADDUPROF(p);
    297 		}
    298 		/* Check whether we are being preempted. */
    299 		if (curcpu()->ci_want_resched)
    300 			preempt(0);
    301 		KERNEL_PROC_UNLOCK(l);
    302 		break;
    303 
    304 
    305 	case EXC_ALI|EXC_USER:
    306 		KERNEL_PROC_LOCK(l);
    307 		if (fix_unaligned(l, frame) != 0) {
    308 			KSI_INIT_TRAP(&ksi);
    309 			ksi.ksi_signo = SIGBUS;
    310 			ksi.ksi_trap = EXC_ALI;
    311 			ksi.ksi_addr = (void *)frame->dar;
    312 			trapsignal(l, &ksi);
    313 		} else
    314 			frame->srr0 += 4;
    315 		KERNEL_PROC_UNLOCK(l);
    316 		break;
    317 
    318 	case EXC_PGM|EXC_USER:
    319 		/*
    320 		 * Illegal insn:
    321 		 *
    322 		 * let's try to see if it's FPU and can be emulated.
    323 		 */
    324 		uvmexp.traps++;
    325 		if (!(l->l_addr->u_pcb.pcb_flags & PCB_FPU)) {
    326 			memset(&l->l_addr->u_pcb.pcb_fpu, 0,
    327 				sizeof l->l_addr->u_pcb.pcb_fpu);
    328 			l->l_addr->u_pcb.pcb_flags |= PCB_FPU;
    329 		}
    330 
    331 		if ((rv = fpu_emulate(frame,
    332 			(struct fpreg *)&l->l_addr->u_pcb.pcb_fpu))) {
    333 			KSI_INIT_TRAP(&ksi);
    334 			ksi.ksi_signo = rv;
    335 			ksi.ksi_trap = EXC_PGM;
    336 			ksi.ksi_addr = (void *)frame->srr0;
    337 			KERNEL_PROC_LOCK(l);
    338 			trapsignal(l, &ksi);
    339 			KERNEL_PROC_UNLOCK(l);
    340 		}
    341 		break;
    342 
    343 	case EXC_MCHK:
    344 		{
    345 			struct faultbuf *fb;
    346 
    347 			if ((fb = l->l_addr->u_pcb.pcb_onfault) != NULL) {
    348 				frame->tf_xtra[TF_PID] = KERNEL_PID;
    349 				frame->srr0 = fb->fb_pc;
    350 				frame->srr1 |= PSL_IR; /* Re-enable IMMU */
    351 				frame->fixreg[1] = fb->fb_sp;
    352 				frame->fixreg[2] = fb->fb_r2;
    353 				frame->fixreg[3] = 1; /* Return TRUE */
    354 				frame->cr = fb->fb_cr;
    355 				memcpy(&frame->fixreg[13], fb->fb_fixreg,
    356 				    sizeof(fb->fb_fixreg));
    357 				goto done;
    358 			}
    359 		}
    360 		goto brain_damage;
    361 	default:
    362  brain_damage:
    363 		printf("trap type 0x%x at 0x%lx\n", type, frame->srr0);
    364 #ifdef DDB
    365 		if (kdb_trap(type, frame))
    366 			goto done;
    367 #endif
    368 #ifdef TRAP_PANICWAIT
    369 		printf("Press a key to panic.\n");
    370 		cngetc();
    371 #endif
    372 		panic("trap");
    373 	}
    374 
    375 	/* Invoke MI userret code */
    376 	mi_userret(l);
    377 
    378 	curcpu()->ci_schedstate.spc_curpriority = l->l_priority = l->l_usrpri;
    379  done:
    380 	return;
    381 }
    382 
    383 int
    384 ctx_setup(int ctx, int srr1)
    385 {
    386 	volatile struct pmap *pm;
    387 
    388 	/* Update PID if we're returning to user mode. */
    389 	if (srr1 & PSL_PR) {
    390 		pm = curproc->p_vmspace->vm_map.pmap;
    391 		if (!pm->pm_ctx) {
    392 			ctx_alloc(__UNVOLATILE(pm));
    393 		}
    394 		ctx = pm->pm_ctx;
    395 		if (srr1 & PSL_SE) {
    396 			int dbreg, mask = 0x48000000;
    397 				/*
    398 				 * Set the Internal Debug and
    399 				 * Instruction Completion bits of
    400 				 * the DBCR0 register.
    401 				 *
    402 				 * XXX this is also used by jtag debuggers...
    403 				 */
    404 			__asm volatile("mfspr %0,0x3f2;"
    405 			    "or %0,%0,%1;"
    406 			    "mtspr 0x3f2,%0;" :
    407 			    "=&r" (dbreg) : "r" (mask));
    408 		}
    409 	}
    410 	else if (!ctx) {
    411 		ctx = KERNEL_PID;
    412 	}
    413 	return (ctx);
    414 }
    415 
    416 /*
    417  * Used by copyin()/copyout()
    418  */
    419 extern vaddr_t vmaprange __P((struct proc *, vaddr_t, vsize_t, int));
    420 extern void vunmaprange __P((vaddr_t, vsize_t));
    421 static int bigcopyin __P((const void *, void *, size_t ));
    422 static int bigcopyout __P((const void *, void *, size_t ));
    423 
    424 int
    425 copyin(const void *udaddr, void *kaddr, size_t len)
    426 {
    427 	struct pmap *pm = curproc->p_vmspace->vm_map.pmap;
    428 	int msr, pid, tmp, ctx;
    429 	struct faultbuf env;
    430 
    431 	/* For bigger buffers use the faster copy */
    432 	if (len > 256)
    433 		return (bigcopyin(udaddr, kaddr, len));
    434 
    435 	if (setfault(&env)) {
    436 		curpcb->pcb_onfault = 0;
    437 		return EFAULT;
    438 	}
    439 
    440 	if (!(ctx = pm->pm_ctx)) {
    441 		/* No context -- assign it one */
    442 		ctx_alloc(pm);
    443 		ctx = pm->pm_ctx;
    444 	}
    445 
    446 	__asm volatile("addi %6,%6,1; mtctr %6;"	/* Set up counter */
    447 		"mfmsr %0;"			/* Save MSR */
    448 		"li %1,0x20; "
    449 		"andc %1,%0,%1; mtmsr %1;"	/* Disable IMMU */
    450 		"mfpid %1;"			/* Save old PID */
    451 		"sync; isync;"
    452 
    453 		"1: bdz 2f;"			/* while len */
    454 		"mtpid %3; sync;"		/* Load user ctx */
    455 		"lbz %2,0(%4); addi %4,%4,1;"	/* Load byte */
    456 		"sync; isync;"
    457 		"mtpid %1;sync;"
    458 		"stb %2,0(%5); dcbf 0,%5; addi %5,%5,1;" /* Store kernel byte */
    459 		"sync; isync;"
    460 		"b 1b;"				/* repeat */
    461 
    462 		"2: mtpid %1; mtmsr %0;"	/* Restore PID and MSR */
    463 		"sync; isync;"
    464 		: "=&r" (msr), "=&r" (pid), "=&r" (tmp)
    465 		: "r" (ctx), "b" (udaddr), "b" (kaddr), "b" (len));
    466 
    467 	curpcb->pcb_onfault = 0;
    468 	return 0;
    469 }
    470 
    471 static int
    472 bigcopyin(const void *udaddr, void *kaddr, size_t len)
    473 {
    474 	const char *up;
    475 	char *kp = kaddr;
    476 	struct lwp *l = curlwp;
    477 	struct proc *p;
    478 	int error;
    479 
    480 	if (!l) {
    481 		return EFAULT;
    482 	}
    483 
    484 	p = l->l_proc;
    485 
    486 	/*
    487 	 * Stolen from physio():
    488 	 */
    489 	PHOLD(l);
    490 	error = uvm_vslock(p, __UNCONST(udaddr), len, VM_PROT_READ);
    491 	if (error) {
    492 		PRELE(l);
    493 		return EFAULT;
    494 	}
    495 	up = (char *)vmaprange(p, (vaddr_t)udaddr, len, VM_PROT_READ);
    496 
    497 	memcpy(kp, up, len);
    498 	vunmaprange((vaddr_t)up, len);
    499 	uvm_vsunlock(p, __UNCONST(udaddr), len);
    500 	PRELE(l);
    501 
    502 	return 0;
    503 }
    504 
    505 int
    506 copyout(const void *kaddr, void *udaddr, size_t len)
    507 {
    508 	struct pmap *pm = curproc->p_vmspace->vm_map.pmap;
    509 	int msr, pid, tmp, ctx;
    510 	struct faultbuf env;
    511 
    512 	/* For big copies use more efficient routine */
    513 	if (len > 256)
    514 		return (bigcopyout(kaddr, udaddr, len));
    515 
    516 	if (setfault(&env)) {
    517 		curpcb->pcb_onfault = 0;
    518 		return EFAULT;
    519 	}
    520 
    521 	if (!(ctx = pm->pm_ctx)) {
    522 		/* No context -- assign it one */
    523 		ctx_alloc(pm);
    524 		ctx = pm->pm_ctx;
    525 	}
    526 
    527 	__asm volatile("addi %6,%6,1; mtctr %6;"	/* Set up counter */
    528 		"mfmsr %0;"			/* Save MSR */
    529 		"li %1,0x20; "
    530 		"andc %1,%0,%1; mtmsr %1;"	/* Disable IMMU */
    531 		"mfpid %1;"			/* Save old PID */
    532 		"sync; isync;"
    533 
    534 		"1: bdz 2f;"			/* while len */
    535 		"mtpid %1;sync;"
    536 		"lbz %2,0(%5); addi %5,%5,1;"	/* Load kernel byte */
    537 		"sync; isync;"
    538 		"mtpid %3; sync;"		/* Load user ctx */
    539 		"stb %2,0(%4);  dcbf 0,%4; addi %4,%4,1;" /* Store user byte */
    540 		"sync; isync;"
    541 		"b 1b;"				/* repeat */
    542 
    543 		"2: mtpid %1; mtmsr %0;"	/* Restore PID and MSR */
    544 		"sync; isync;"
    545 		: "=&r" (msr), "=&r" (pid), "=&r" (tmp)
    546 		: "r" (ctx), "b" (udaddr), "b" (kaddr), "b" (len));
    547 
    548 	curpcb->pcb_onfault = 0;
    549 	return 0;
    550 }
    551 
    552 static int
    553 bigcopyout(const void *kaddr, void *udaddr, size_t len)
    554 {
    555 	char *up;
    556 	const char *kp = (const char *)kaddr;
    557 	struct lwp *l = curlwp;
    558 	struct proc *p;
    559 	int error;
    560 
    561 	if (!l) {
    562 		return EFAULT;
    563 	}
    564 
    565 	p = l->l_proc;
    566 
    567 	/*
    568 	 * Stolen from physio():
    569 	 */
    570 	PHOLD(l);
    571 	error = uvm_vslock(p, udaddr, len, VM_PROT_WRITE);
    572 	if (error) {
    573 		PRELE(l);
    574 		return EFAULT;
    575 	}
    576 	up = (char *)vmaprange(p, (vaddr_t)udaddr, len,
    577 	    VM_PROT_READ | VM_PROT_WRITE);
    578 
    579 	memcpy(up, kp, len);
    580 	vunmaprange((vaddr_t)up, len);
    581 	uvm_vsunlock(p, udaddr, len);
    582 	PRELE(l);
    583 
    584 	return 0;
    585 }
    586 
    587 /*
    588  * kcopy(const void *src, void *dst, size_t len);
    589  *
    590  * Copy len bytes from src to dst, aborting if we encounter a fatal
    591  * page fault.
    592  *
    593  * kcopy() _must_ save and restore the old fault handler since it is
    594  * called by uiomove(), which may be in the path of servicing a non-fatal
    595  * page fault.
    596  */
    597 int
    598 kcopy(const void *src, void *dst, size_t len)
    599 {
    600 	struct faultbuf env, *oldfault;
    601 
    602 	oldfault = curpcb->pcb_onfault;
    603 	if (setfault(&env)) {
    604 		curpcb->pcb_onfault = oldfault;
    605 		return EFAULT;
    606 	}
    607 
    608 	memcpy(dst, src, len);
    609 
    610 	curpcb->pcb_onfault = oldfault;
    611 	return 0;
    612 }
    613 
    614 int
    615 badaddr(void *addr, size_t size)
    616 {
    617 
    618 	return badaddr_read(addr, size, NULL);
    619 }
    620 
    621 int
    622 badaddr_read(void *addr, size_t size, int *rptr)
    623 {
    624 	struct faultbuf env;
    625 	int x;
    626 
    627 	/* Get rid of any stale machine checks that have been waiting.  */
    628 	__asm volatile ("sync; isync");
    629 
    630 	if (setfault(&env)) {
    631 		curpcb->pcb_onfault = 0;
    632 		__asm volatile ("sync");
    633 		return 1;
    634 	}
    635 
    636 	__asm volatile ("sync");
    637 
    638 	switch (size) {
    639 	case 1:
    640 		x = *(volatile int8_t *)addr;
    641 		break;
    642 	case 2:
    643 		x = *(volatile int16_t *)addr;
    644 		break;
    645 	case 4:
    646 		x = *(volatile int32_t *)addr;
    647 		break;
    648 	default:
    649 		panic("badaddr: invalid size (%d)", size);
    650 	}
    651 
    652 	/* Make sure we took the machine check, if we caused one. */
    653 	__asm volatile ("sync; isync");
    654 
    655 	curpcb->pcb_onfault = 0;
    656 	__asm volatile ("sync");	/* To be sure. */
    657 
    658 	/* Use the value to avoid reorder. */
    659 	if (rptr)
    660 		*rptr = x;
    661 
    662 	return 0;
    663 }
    664 
    665 /*
    666  * For now, this only deals with the particular unaligned access case
    667  * that gcc tends to generate.  Eventually it should handle all of the
    668  * possibilities that can happen on a 32-bit PowerPC in big-endian mode.
    669  */
    670 
    671 static int
    672 fix_unaligned(struct lwp *l, struct trapframe *frame)
    673 {
    674 
    675 	return -1;
    676 }
    677 
    678 /*
    679  * Start a new LWP
    680  */
    681 void
    682 startlwp(arg)
    683 	void *arg;
    684 {
    685 	int err;
    686 	ucontext_t *uc = arg;
    687 	struct lwp *l = curlwp;
    688 
    689 	err = cpu_setmcontext(l, &uc->uc_mcontext, uc->uc_flags);
    690 #if DIAGNOSTIC
    691 	if (err) {
    692 		printf("Error %d from cpu_setmcontext.", err);
    693 	}
    694 #endif
    695 	pool_put(&lwp_uc_pool, uc);
    696 
    697 	upcallret(l);
    698 }
    699 
    700 /*
    701  * XXX This is a terrible name.
    702  */
    703 void
    704 upcallret(l)
    705 	struct lwp *l;
    706 {
    707 
    708 	/* Invoke MI userret code */
    709 	mi_userret(l);
    710 
    711 	curcpu()->ci_schedstate.spc_curpriority = l->l_priority = l->l_usrpri;
    712 }
    713