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trap.c revision 1.11
      1 /*	$NetBSD: trap.c,v 1.11 2003/02/02 20:43:23 matt 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 "opt_altivec.h"
     70 #include "opt_ddb.h"
     71 #include "opt_ktrace.h"
     72 #include "opt_systrace.h"
     73 #include "opt_syscall_debug.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 #ifdef KTRACE
     82 #include <sys/ktrace.h>
     83 #endif
     84 #include <sys/pool.h>
     85 #include <sys/sa.h>
     86 #include <sys/savar.h>
     87 #ifdef SYSTRACE
     88 #include <sys/systrace.h>
     89 #endif
     90 
     91 #include <uvm/uvm_extern.h>
     92 
     93 #include <dev/cons.h>
     94 
     95 #include <machine/cpu.h>
     96 #include <machine/db_machdep.h>
     97 #include <machine/fpu.h>
     98 #include <machine/frame.h>
     99 #include <machine/pcb.h>
    100 #include <machine/psl.h>
    101 #include <machine/trap.h>
    102 
    103 #include <powerpc/spr.h>
    104 #include <powerpc/ibm4xx/pmap.h>
    105 #include <powerpc/ibm4xx/tlb.h>
    106 #include <powerpc/fpu/fpu_extern.h>
    107 
    108 /* These definitions should probably be somewhere else			XXX */
    109 #define	FIRSTARG	3		/* first argument is in reg 3 */
    110 #define	NARGREG		8		/* 8 args are in registers */
    111 #define	MOREARGS(sp)	((caddr_t)((int)(sp) + 8)) /* more args go here */
    112 
    113 static int fix_unaligned __P((struct lwp *l, struct trapframe *frame));
    114 
    115 void trap __P((struct trapframe *));	/* Called from locore / trap_subr */
    116 /* Why are these not defined in a header? */
    117 int badaddr __P((void *, size_t));
    118 int badaddr_read __P((void *, size_t, int *));
    119 int ctx_setup __P((int, int));
    120 
    121 #ifdef DEBUG
    122 #define TDB_ALL	0x1
    123 int trapdebug = /* TDB_ALL */ 0;
    124 #define	DBPRINTF(x, y)	if (trapdebug & (x)) printf y
    125 #else
    126 #define DBPRINTF(x, y)
    127 #endif
    128 
    129 void
    130 trap(struct trapframe *frame)
    131 {
    132 	struct lwp *l = curlwp;
    133 	struct proc *p = l ? l->l_proc : NULL;
    134 	int type = frame->exc;
    135 	int ftype, rv;
    136 
    137 	KASSERT(l == 0 || (l->l_stat == LSONPROC));
    138 
    139 	if (frame->srr1 & PSL_PR)
    140 		type |= EXC_USER;
    141 
    142 	ftype = VM_PROT_READ;
    143 
    144 DBPRINTF(TDB_ALL, ("trap(%x) at %x from frame %p &frame %p\n",
    145 	type, frame->srr0, frame, &frame));
    146 
    147 	switch (type) {
    148 	case EXC_DEBUG|EXC_USER:
    149 {
    150 	int srr2, srr3;
    151 __asm __volatile("mfspr %0,0x3f0" : "=r" (rv), "=r" (srr2), "=r" (srr3) :);
    152 printf("debug reg is %x srr2 %x srr3 %x\n", rv, srr2, srr3);
    153 }
    154 		/*
    155 		 * DEBUG intr -- probably single-step.
    156 		 */
    157 	case EXC_TRC|EXC_USER:
    158 		KERNEL_PROC_LOCK(l);
    159 		frame->srr1 &= ~PSL_SE;
    160 		trapsignal(l, SIGTRAP, EXC_TRC);
    161 		KERNEL_PROC_UNLOCK(l);
    162 		break;
    163 
    164 	  /* If we could not find and install appropriate TLB entry, fall through */
    165 
    166 	case EXC_DSI:
    167 		/* FALLTHROUGH */
    168 	case EXC_DTMISS:
    169 		{
    170 			struct vm_map *map;
    171 			vaddr_t va;
    172 			struct faultbuf *fb = NULL;
    173 
    174 			KERNEL_LOCK(LK_CANRECURSE|LK_EXCLUSIVE);
    175 			va = frame->dar;
    176 			if (frame->tf_xtra[TF_PID] == KERNEL_PID) {
    177 				map = kernel_map;
    178 			} else {
    179 				map = &p->p_vmspace->vm_map;
    180 			}
    181 
    182 			if (frame->tf_xtra[TF_ESR] & (ESR_DST|ESR_DIZ))
    183 				ftype = VM_PROT_WRITE;
    184 
    185 DBPRINTF(TDB_ALL, ("trap(EXC_DSI) at %x %s fault on %p esr %x\n",
    186 frame->srr0, (ftype&VM_PROT_WRITE) ? "write" : "read", (void *)va, frame->tf_xtra[TF_ESR]));
    187 			rv = uvm_fault(map, trunc_page(va), 0, ftype);
    188 			KERNEL_UNLOCK();
    189 			if (rv == 0)
    190 				goto done;
    191 			if ((fb = l->l_addr->u_pcb.pcb_onfault) != NULL) {
    192 				frame->tf_xtra[TF_PID] = KERNEL_PID;
    193 				frame->srr0 = fb->fb_pc;
    194 				frame->srr1 |= PSL_IR; /* Re-enable IMMU */
    195 				frame->fixreg[1] = fb->fb_sp;
    196 				frame->fixreg[2] = fb->fb_r2;
    197 				frame->fixreg[3] = 1; /* Return TRUE */
    198 				frame->cr = fb->fb_cr;
    199 				memcpy(&frame->fixreg[13], fb->fb_fixreg,
    200 				    sizeof(fb->fb_fixreg));
    201 				goto done;
    202 			}
    203 		}
    204 		goto brain_damage;
    205 
    206 	case EXC_DSI|EXC_USER:
    207 		/* FALLTHROUGH */
    208 	case EXC_DTMISS|EXC_USER:
    209 		KERNEL_PROC_LOCK(l);
    210 
    211 		if (frame->tf_xtra[TF_ESR] & (ESR_DST|ESR_DIZ))
    212 			ftype = VM_PROT_WRITE;
    213 
    214 DBPRINTF(TDB_ALL, ("trap(EXC_DSI|EXC_USER) at %x %s fault on %x %x\n",
    215 frame->srr0, (ftype&VM_PROT_WRITE) ? "write" : "read", frame->dar, frame->tf_xtra[TF_ESR]));
    216 KASSERT(l == curlwp && (l->l_stat == LSONPROC));
    217 		rv = uvm_fault(&p->p_vmspace->vm_map,
    218 			       trunc_page(frame->dar), 0, ftype);
    219 		if (rv == 0) {
    220 		  KERNEL_PROC_UNLOCK(l);
    221 		  break;
    222 		}
    223 		if (rv == ENOMEM) {
    224 			printf("UVM: pid %d (%s) lid %d, uid %d killed: "
    225 			       "out of swap\n",
    226 			       p->p_pid, p->p_comm, l->l_lid,
    227 			       p->p_cred && p->p_ucred ?
    228 			       p->p_ucred->cr_uid : -1);
    229 			trapsignal(l, SIGKILL, EXC_DSI);
    230 		} else {
    231 			trapsignal(l, SIGSEGV, EXC_DSI);
    232 		}
    233 		KERNEL_PROC_UNLOCK(l);
    234 		break;
    235 	case EXC_ITMISS|EXC_USER:
    236 	case EXC_ISI|EXC_USER:
    237 		KERNEL_PROC_LOCK(l);
    238 		ftype = VM_PROT_READ | VM_PROT_EXECUTE;
    239 DBPRINTF(TDB_ALL, ("trap(EXC_ISI|EXC_USER) at %x %s fault on %x tf %p\n",
    240 frame->srr0, (ftype&VM_PROT_WRITE) ? "write" : "read", frame->srr0, frame));
    241 		rv = uvm_fault(&p->p_vmspace->vm_map, trunc_page(frame->srr0), 0, ftype);
    242 		if (rv == 0) {
    243 		  KERNEL_PROC_UNLOCK(l);
    244 		  break;
    245 		}
    246 		trapsignal(l, SIGSEGV, EXC_ISI);
    247 		KERNEL_PROC_UNLOCK(l);
    248 		break;
    249 
    250 	case EXC_AST|EXC_USER:
    251 		curcpu()->ci_astpending = 0;	/* we are about to do it */
    252 		KERNEL_PROC_LOCK(l);
    253 		uvmexp.softs++;
    254 		if (p->p_flag & P_OWEUPC) {
    255 			p->p_flag &= ~P_OWEUPC;
    256 			ADDUPROF(p);
    257 		}
    258 		/* Check whether we are being preempted. */
    259 		if (curcpu()->ci_want_resched)
    260 			preempt(0);
    261 		KERNEL_PROC_UNLOCK(l);
    262 		break;
    263 
    264 
    265 	case EXC_ALI|EXC_USER:
    266 		KERNEL_PROC_LOCK(l);
    267 		if (fix_unaligned(l, frame) != 0)
    268 			trapsignal(l, SIGBUS, EXC_ALI);
    269 		else
    270 			frame->srr0 += 4;
    271 		KERNEL_PROC_UNLOCK(l);
    272 		break;
    273 
    274 	case EXC_PGM|EXC_USER:
    275 		/*
    276 		 * Illegal insn:
    277 		 *
    278 		 * let's try to see if it's FPU and can be emulated.
    279 		 */
    280 		uvmexp.traps ++;
    281 		if (!(l->l_addr->u_pcb.pcb_flags & PCB_FPU)) {
    282 			memset(&l->l_addr->u_pcb.pcb_fpu, 0,
    283 				sizeof l->l_addr->u_pcb.pcb_fpu);
    284 			l->l_addr->u_pcb.pcb_flags |= PCB_FPU;
    285 		}
    286 
    287 		if ((rv = fpu_emulate(frame,
    288 			(struct fpreg *)&l->l_addr->u_pcb.pcb_fpu))) {
    289 			KERNEL_PROC_LOCK(l);
    290 			trapsignal(l, rv, EXC_PGM);
    291 			KERNEL_PROC_UNLOCK(l);
    292 		}
    293 		break;
    294 
    295 	case EXC_MCHK:
    296 		{
    297 			struct faultbuf *fb;
    298 
    299 			if ((fb = l->l_addr->u_pcb.pcb_onfault) != NULL) {
    300 				frame->tf_xtra[TF_PID] = KERNEL_PID;
    301 				frame->srr0 = fb->fb_pc;
    302 				frame->srr1 |= PSL_IR; /* Re-enable IMMU */
    303 				frame->fixreg[1] = fb->fb_sp;
    304 				frame->fixreg[2] = fb->fb_r2;
    305 				frame->fixreg[3] = 1; /* Return TRUE */
    306 				frame->cr = fb->fb_cr;
    307 				memcpy(&frame->fixreg[13], fb->fb_fixreg,
    308 				    sizeof(fb->fb_fixreg));
    309 				goto done;
    310 			}
    311 		}
    312 		goto brain_damage;
    313 	default:
    314 brain_damage:
    315 		printf("trap type 0x%x at 0x%lx\n", type, frame->srr0);
    316 #ifdef DDB
    317 		if (kdb_trap(type, frame))
    318 			goto done;
    319 #endif
    320 #ifdef TRAP_PANICWAIT
    321 		printf("Press a key to panic.\n");
    322 		cngetc();
    323 #endif
    324 		panic("trap");
    325 	}
    326 
    327 	/* Take pending signals. */
    328 	{
    329 		int sig;
    330 
    331 		while ((sig = CURSIG(l)) != 0)
    332 			postsig(sig);
    333 	}
    334 
    335 	/* Invoke per-process kernel-exit handling, if any */
    336 	if (p->p_userret)
    337 		(p->p_userret)(l, p->p_userret_arg);
    338 
    339 	/* Invoke any pending upcalls */
    340 	while (l->l_flag & L_SA_UPCALL)
    341 		sa_upcall_userret(l);
    342 
    343 	curcpu()->ci_schedstate.spc_curpriority = l->l_priority = l->l_usrpri;
    344   done:
    345 	return;
    346 }
    347 
    348 int
    349 ctx_setup(int ctx, int srr1)
    350 {
    351 	volatile struct pmap *pm;
    352 
    353 	/* Update PID if we're returning to user mode. */
    354 	if (srr1 & PSL_PR) {
    355 		pm = curproc->p_vmspace->vm_map.pmap;
    356 		if (!pm->pm_ctx) {
    357 			ctx_alloc((struct pmap *)pm);
    358 		}
    359 		ctx = pm->pm_ctx;
    360 		if (srr1 & PSL_SE) {
    361 			int dbreg, mask = 0x48000000;
    362 				/*
    363 				 * Set the Internal Debug and
    364 				 * Instruction Completion bits of
    365 				 * the DBCR0 register.
    366 				 *
    367 				 * XXX this is also used by jtag debuggers...
    368 				 */
    369 			__asm __volatile("mfspr %0,0x3f2;"
    370 				"or %0,%0,%1;"
    371 				"mtspr 0x3f2,%0;" :
    372 				"=&r" (dbreg) : "r" (mask));
    373 		}
    374 	}
    375 	else if (!ctx) {
    376 		ctx = KERNEL_PID;
    377 	}
    378 	return (ctx);
    379 }
    380 
    381 /*
    382  * Used by copyin()/copyout()
    383  */
    384 extern vaddr_t vmaprange __P((struct proc *, vaddr_t, vsize_t, int));
    385 extern void vunmaprange __P((vaddr_t, vsize_t));
    386 static int bigcopyin __P((const void *,	void *,	size_t ));
    387 static int bigcopyout __P((const void *, void *, size_t ));
    388 
    389 int
    390 copyin(const void *udaddr, void *kaddr, size_t len)
    391 {
    392 	struct pmap *pm = curproc->p_vmspace->vm_map.pmap;
    393 	int msr, pid, tmp, ctx;
    394 	struct faultbuf env;
    395 
    396 	/* For bigger buffers use the faster copy */
    397 	if (len > 256) return (bigcopyin(udaddr, kaddr, len));
    398 
    399 	if (setfault(&env)) {
    400 		curpcb->pcb_onfault = 0;
    401 		return EFAULT;
    402 	}
    403 
    404 	if (!(ctx = pm->pm_ctx)) {
    405 		/* No context -- assign it one */
    406 		ctx_alloc(pm);
    407 		ctx = pm->pm_ctx;
    408 	}
    409 
    410 	asm volatile("addi %6,%6,1; mtctr %6;"	/* Set up counter */
    411 		"mfmsr %0;"			/* Save MSR */
    412 		"li %1,0x20; "
    413 		"andc %1,%0,%1; mtmsr %1;"	/* Disable IMMU */
    414 		"mfpid %1;"			/* Save old PID */
    415 		"sync; isync;"
    416 
    417 		"1: bdz 2f;"			/* while len */
    418 		"mtpid %3; sync;"		/* Load user ctx */
    419 		"lbz %2,0(%4); addi %4,%4,1;"	/* Load byte */
    420 		"sync; isync;"
    421 		"mtpid %1;sync;"
    422 		"stb %2,0(%5); dcbf 0,%5; addi %5,%5,1;"	/* Store kernel byte */
    423 		"sync; isync;"
    424 		"b 1b;"				/* repeat */
    425 
    426 		"2: mtpid %1; mtmsr %0;"	/* Restore PID and MSR */
    427 		"sync; isync;"
    428 		: "=&r" (msr), "=&r" (pid), "=&r" (tmp)
    429 		: "r" (ctx), "r" (udaddr), "r" (kaddr), "r" (len));
    430 
    431 	curpcb->pcb_onfault = 0;
    432 	return 0;
    433 }
    434 
    435 static int
    436 bigcopyin(const void *udaddr, void *kaddr, size_t len)
    437 {
    438 	const char *up;
    439 	char *kp = kaddr;
    440 	struct lwp *l = curlwp;
    441 	struct proc *p;
    442 	int error;
    443 
    444 	if (!l) {
    445 		return EFAULT;
    446 	}
    447 
    448 	p = l->l_proc;
    449 
    450 	/*
    451 	 * Stolen from physio():
    452 	 */
    453 	PHOLD(l);
    454 	error = uvm_vslock(p, (caddr_t)udaddr, len, VM_PROT_READ);
    455 	if (error) {
    456 		PRELE(l);
    457 		return EFAULT;
    458 	}
    459 	up = (char *)vmaprange(p, (vaddr_t)udaddr, len, VM_PROT_READ);
    460 
    461 	memcpy(kp, up, len);
    462 	vunmaprange((vaddr_t)up, len);
    463 	uvm_vsunlock(p, (caddr_t)udaddr, len);
    464 	PRELE(l);
    465 
    466 	return 0;
    467 }
    468 
    469 int
    470 copyout(const void *kaddr, void *udaddr, size_t len)
    471 {
    472 	struct pmap *pm = curproc->p_vmspace->vm_map.pmap;
    473 	int msr, pid, tmp, ctx;
    474 	struct faultbuf env;
    475 
    476 	/* For big copies use more efficient routine */
    477 	if (len > 256) return (bigcopyout(kaddr, udaddr, len));
    478 
    479 	if (setfault(&env)) {
    480 		curpcb->pcb_onfault = 0;
    481 		return EFAULT;
    482 	}
    483 
    484 	if (!(ctx = pm->pm_ctx)) {
    485 		/* No context -- assign it one */
    486 		ctx_alloc(pm);
    487 		ctx = pm->pm_ctx;
    488 	}
    489 
    490 	asm volatile("addi %6,%6,1; mtctr %6;"	/* Set up counter */
    491 		"mfmsr %0;"			/* Save MSR */
    492 		"li %1,0x20; "
    493 		"andc %1,%0,%1; mtmsr %1;"	/* Disable IMMU */
    494 		"mfpid %1;"			/* Save old PID */
    495 		"sync; isync;"
    496 
    497 		"1: bdz 2f;"			/* while len */
    498 		"mtpid %1;sync;"
    499 		"lbz %2,0(%5); addi %5,%5,1;"	/* Load kernel byte */
    500 		"sync; isync;"
    501 		"mtpid %3; sync;"		/* Load user ctx */
    502 		"stb %2,0(%4);  dcbf 0,%4; addi %4,%4,1;"	/* Store user byte */
    503 		"sync; isync;"
    504 		"b 1b;"				/* repeat */
    505 
    506 		"2: mtpid %1; mtmsr %0;"	/* Restore PID and MSR */
    507 		"sync; isync;"
    508 		: "=&r" (msr), "=&r" (pid), "=&r" (tmp)
    509 		: "r" (ctx), "r" (udaddr), "r" (kaddr), "r" (len));
    510 
    511 	curpcb->pcb_onfault = 0;
    512 	return 0;
    513 }
    514 
    515 static int
    516 bigcopyout(const void *kaddr, void *udaddr, size_t len)
    517 {
    518 	char *up;
    519 	const char *kp = (char *)kaddr;
    520 	struct lwp *l = curlwp;
    521 	struct proc *p;
    522 	int error;
    523 
    524 	if (!l) {
    525 		return EFAULT;
    526 	}
    527 
    528 	p = l->l_proc;
    529 
    530 	/*
    531 	 * Stolen from physio():
    532 	 */
    533 	PHOLD(l);
    534 	error = uvm_vslock(p, udaddr, len, VM_PROT_WRITE);
    535 	if (error) {
    536 		PRELE(l);
    537 		return EFAULT;
    538 	}
    539 	up = (char *)vmaprange(p, (vaddr_t)udaddr, len,
    540 		VM_PROT_READ|VM_PROT_WRITE);
    541 
    542 	memcpy(up, kp, len);
    543 	vunmaprange((vaddr_t)up, len);
    544 	uvm_vsunlock(p, udaddr, len);
    545 	PRELE(l);
    546 
    547 	return 0;
    548 }
    549 
    550 /*
    551  * kcopy(const void *src, void *dst, size_t len);
    552  *
    553  * Copy len bytes from src to dst, aborting if we encounter a fatal
    554  * page fault.
    555  *
    556  * kcopy() _must_ save and restore the old fault handler since it is
    557  * called by uiomove(), which may be in the path of servicing a non-fatal
    558  * page fault.
    559  */
    560 int
    561 kcopy(const void *src, void *dst, size_t len)
    562 {
    563 	struct faultbuf env, *oldfault;
    564 
    565 	oldfault = curpcb->pcb_onfault;
    566 	if (setfault(&env)) {
    567 		curpcb->pcb_onfault = oldfault;
    568 		return EFAULT;
    569 	}
    570 
    571 	memcpy(dst, src, len);
    572 
    573 	curpcb->pcb_onfault = oldfault;
    574 	return 0;
    575 }
    576 
    577 int
    578 badaddr(void *addr, size_t size)
    579 {
    580 
    581 	return badaddr_read(addr, size, NULL);
    582 }
    583 
    584 int
    585 badaddr_read(void *addr, size_t size, int *rptr)
    586 {
    587 	struct faultbuf env;
    588 	int x;
    589 
    590 	/* Get rid of any stale machine checks that have been waiting.  */
    591 	__asm __volatile ("sync; isync");
    592 
    593 	if (setfault(&env)) {
    594 		curpcb->pcb_onfault = 0;
    595 		__asm __volatile ("sync");
    596 		return 1;
    597 	}
    598 
    599 	__asm __volatile ("sync");
    600 
    601 	switch (size) {
    602 	case 1:
    603 		x = *(volatile int8_t *)addr;
    604 		break;
    605 	case 2:
    606 		x = *(volatile int16_t *)addr;
    607 		break;
    608 	case 4:
    609 		x = *(volatile int32_t *)addr;
    610 		break;
    611 	default:
    612 		panic("badaddr: invalid size (%d)", size);
    613 	}
    614 
    615 	/* Make sure we took the machine check, if we caused one. */
    616 	__asm __volatile ("sync; isync");
    617 
    618 	curpcb->pcb_onfault = 0;
    619 	__asm __volatile ("sync");	/* To be sure. */
    620 
    621 	/* Use the value to avoid reorder. */
    622 	if (rptr)
    623 		*rptr = x;
    624 
    625 	return 0;
    626 }
    627 
    628 /*
    629  * For now, this only deals with the particular unaligned access case
    630  * that gcc tends to generate.  Eventually it should handle all of the
    631  * possibilities that can happen on a 32-bit PowerPC in big-endian mode.
    632  */
    633 
    634 static int
    635 fix_unaligned(struct lwp *l, struct trapframe *frame)
    636 {
    637 
    638 	return -1;
    639 }
    640 
    641 /*
    642  * Start a new LWP
    643  */
    644 void
    645 startlwp(arg)
    646 	void *arg;
    647 {
    648 	int err;
    649 	ucontext_t *uc = arg;
    650 	struct lwp *l = curlwp;
    651 
    652 	err = cpu_setmcontext(l, &uc->uc_mcontext, uc->uc_flags);
    653 #if DIAGNOSTIC
    654 	if (err) {
    655 		printf("Error %d from cpu_setmcontext.", err);
    656 	}
    657 #endif
    658 	pool_put(&lwp_uc_pool, uc);
    659 
    660 	upcallret(l);
    661 }
    662 
    663 /*
    664  * XXX This is a terrible name.
    665  */
    666 void
    667 upcallret(l)
    668 	struct lwp *l;
    669 {
    670 	int sig;
    671 
    672 	/* Take pending signals. */
    673 	while ((sig = CURSIG(l)) != 0)
    674 		postsig(sig);
    675 
    676 	/* Invoke per-process kernel-exit handling, if any */
    677 	if (l->l_proc->p_userret)
    678 		(l->l_proc->p_userret)(l, l->l_proc->p_userret_arg);
    679 
    680 	/* Invoke any pending upcalls */
    681 	while (l->l_flag & L_SA_UPCALL)
    682 		sa_upcall_userret(l);
    683 
    684 	curcpu()->ci_schedstate.spc_curpriority = l->l_priority = l->l_usrpri;
    685 }
    686