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      1 /*
      2  * CDDL HEADER START
      3  *
      4  * The contents of this file are subject to the terms of the
      5  * Common Development and Distribution License (the "License").
      6  * You may not use this file except in compliance with the License.
      7  *
      8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
      9  * or http://www.opensolaris.org/os/licensing.
     10  * See the License for the specific language governing permissions
     11  * and limitations under the License.
     12  *
     13  * When distributing Covered Code, include this CDDL HEADER in each
     14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
     15  * If applicable, add the following below this CDDL HEADER, with the
     16  * fields enclosed by brackets "[]" replaced with your own identifying
     17  * information: Portions Copyright [yyyy] [name of copyright owner]
     18  *
     19  * CDDL HEADER END
     20  */
     21 
     22 /*
     23  * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
     24  * Use is subject to license terms.
     25  */
     26 
     27 #include <sys/types.h>
     28 #include <sys/t_lock.h>
     29 #include <sys/param.h>
     30 #include <sys/segments.h>
     31 #include <sys/sysmacros.h>
     32 #include <sys/signal.h>
     33 #include <sys/systm.h>
     34 #include <sys/user.h>
     35 #include <sys/mman.h>
     36 #include <sys/vm.h>
     37 
     38 #include <sys/disp.h>
     39 #include <sys/class.h>
     40 
     41 #include <sys/proc.h>
     42 #include <sys/buf.h>
     43 #include <sys/kmem.h>
     44 
     45 #include <sys/reboot.h>
     46 #include <sys/uadmin.h>
     47 #include <sys/callb.h>
     48 
     49 #include <sys/cred.h>
     50 #include <sys/vnode.h>
     51 #include <sys/file.h>
     52 
     53 #include <sys/procfs.h>
     54 #include <sys/acct.h>
     55 
     56 #include <sys/vfs.h>
     57 #include <sys/dnlc.h>
     58 #include <sys/var.h>
     59 #include <sys/cmn_err.h>
     60 #include <sys/utsname.h>
     61 #include <sys/debug.h>
     62 
     63 #include <sys/dumphdr.h>
     64 #include <sys/bootconf.h>
     65 #include <sys/varargs.h>
     66 #include <sys/promif.h>
     67 #include <sys/modctl.h>
     68 
     69 #include <sys/consdev.h>
     70 #include <sys/frame.h>
     71 
     72 #include <sys/sunddi.h>
     73 #include <sys/ddidmareq.h>
     74 #include <sys/psw.h>
     75 #include <sys/regset.h>
     76 #include <sys/privregs.h>
     77 #include <sys/clock.h>
     78 #include <sys/tss.h>
     79 #include <sys/cpu.h>
     80 #include <sys/stack.h>
     81 #include <sys/trap.h>
     82 #include <sys/pic.h>
     83 #include <vm/hat.h>
     84 #include <vm/anon.h>
     85 #include <vm/as.h>
     86 #include <vm/page.h>
     87 #include <vm/seg.h>
     88 #include <vm/seg_kmem.h>
     89 #include <vm/seg_map.h>
     90 #include <vm/seg_vn.h>
     91 #include <vm/seg_kp.h>
     92 #include <vm/hat_i86.h>
     93 #include <sys/swap.h>
     94 #include <sys/thread.h>
     95 #include <sys/sysconf.h>
     96 #include <sys/vm_machparam.h>
     97 #include <sys/archsystm.h>
     98 #include <sys/machsystm.h>
     99 #include <sys/machlock.h>
    100 #include <sys/x_call.h>
    101 #include <sys/instance.h>
    102 
    103 #include <sys/time.h>
    104 #include <sys/smp_impldefs.h>
    105 #include <sys/psm_types.h>
    106 #include <sys/atomic.h>
    107 #include <sys/panic.h>
    108 #include <sys/cpuvar.h>
    109 #include <sys/dtrace.h>
    110 #include <sys/bl.h>
    111 #include <sys/nvpair.h>
    112 #include <sys/x86_archext.h>
    113 #include <sys/pool_pset.h>
    114 #include <sys/autoconf.h>
    115 #include <sys/mem.h>
    116 #include <sys/dumphdr.h>
    117 #include <sys/compress.h>
    118 #include <sys/cpu_module.h>
    119 #if defined(__xpv)
    120 #include <sys/hypervisor.h>
    121 #include <sys/xpv_panic.h>
    122 #endif
    123 
    124 #include <sys/fastboot.h>
    125 #include <sys/machelf.h>
    126 #include <sys/kobj.h>
    127 #include <sys/multiboot.h>
    128 
    129 #ifdef	TRAPTRACE
    130 #include <sys/traptrace.h>
    131 #endif	/* TRAPTRACE */
    132 
    133 extern void audit_enterprom(int);
    134 extern void audit_exitprom(int);
    135 
    136 /*
    137  * Occassionally the kernel knows better whether to power-off or reboot.
    138  */
    139 int force_shutdown_method = AD_UNKNOWN;
    140 
    141 /*
    142  * The panicbuf array is used to record messages and state:
    143  */
    144 char panicbuf[PANICBUFSIZE];
    145 
    146 /*
    147  * maxphys - used during physio
    148  * klustsize - used for klustering by swapfs and specfs
    149  */
    150 int maxphys = 56 * 1024;    /* XXX See vm_subr.c - max b_count in physio */
    151 int klustsize = 56 * 1024;
    152 
    153 caddr_t	p0_va;		/* Virtual address for accessing physical page 0 */
    154 
    155 /*
    156  * defined here, though unused on x86,
    157  * to make kstat_fr.c happy.
    158  */
    159 int vac;
    160 
    161 void debug_enter(char *);
    162 
    163 extern void pm_cfb_check_and_powerup(void);
    164 extern void pm_cfb_rele(void);
    165 
    166 extern fastboot_info_t newkernel;
    167 
    168 /*
    169  * Machine dependent code to reboot.
    170  * "mdep" is interpreted as a character pointer; if non-null, it is a pointer
    171  * to a string to be used as the argument string when rebooting.
    172  *
    173  * "invoke_cb" is a boolean. It is set to true when mdboot() can safely
    174  * invoke CB_CL_MDBOOT callbacks before shutting the system down, i.e. when
    175  * we are in a normal shutdown sequence (interrupts are not blocked, the
    176  * system is not panic'ing or being suspended).
    177  */
    178 /*ARGSUSED*/
    179 void
    180 mdboot(int cmd, int fcn, char *mdep, boolean_t invoke_cb)
    181 {
    182 	processorid_t bootcpuid = 0;
    183 	static int is_first_quiesce = 1;
    184 	static int is_first_reset = 1;
    185 	int reset_status = 0;
    186 	static char fallback_str[] = "Falling back to regular reboot.\n";
    187 
    188 	if (fcn == AD_FASTREBOOT && !newkernel.fi_valid)
    189 		fcn = AD_BOOT;
    190 
    191 	if (!panicstr) {
    192 		kpreempt_disable();
    193 		if (fcn == AD_FASTREBOOT) {
    194 			mutex_enter(&cpu_lock);
    195 			if (CPU_ACTIVE(cpu_get(bootcpuid))) {
    196 				affinity_set(bootcpuid);
    197 			}
    198 			mutex_exit(&cpu_lock);
    199 		} else {
    200 			affinity_set(CPU_CURRENT);
    201 		}
    202 	}
    203 
    204 	if (force_shutdown_method != AD_UNKNOWN)
    205 		fcn = force_shutdown_method;
    206 
    207 	/*
    208 	 * XXX - rconsvp is set to NULL to ensure that output messages
    209 	 * are sent to the underlying "hardware" device using the
    210 	 * monitor's printf routine since we are in the process of
    211 	 * either rebooting or halting the machine.
    212 	 */
    213 	rconsvp = NULL;
    214 
    215 	/*
    216 	 * Print the reboot message now, before pausing other cpus.
    217 	 * There is a race condition in the printing support that
    218 	 * can deadlock multiprocessor machines.
    219 	 */
    220 	if (!(fcn == AD_HALT || fcn == AD_POWEROFF))
    221 		prom_printf("rebooting...\n");
    222 
    223 	if (IN_XPV_PANIC())
    224 		reset();
    225 
    226 	/*
    227 	 * We can't bring up the console from above lock level, so do it now
    228 	 */
    229 	pm_cfb_check_and_powerup();
    230 
    231 	/* make sure there are no more changes to the device tree */
    232 	devtree_freeze();
    233 
    234 	if (invoke_cb)
    235 		(void) callb_execute_class(CB_CL_MDBOOT, NULL);
    236 
    237 	/*
    238 	 * Clear any unresolved UEs from memory.
    239 	 */
    240 	page_retire_mdboot();
    241 
    242 #if defined(__xpv)
    243 	/*
    244 	 * XXPV	Should probably think some more about how we deal
    245 	 *	with panicing before it's really safe to panic.
    246 	 *	On hypervisors, we reboot very quickly..  Perhaps panic
    247 	 *	should only attempt to recover by rebooting if,
    248 	 *	say, we were able to mount the root filesystem,
    249 	 *	or if we successfully launched init(1m).
    250 	 */
    251 	if (panicstr && proc_init == NULL)
    252 		(void) HYPERVISOR_shutdown(SHUTDOWN_poweroff);
    253 #endif
    254 	/*
    255 	 * stop other cpus and raise our priority.  since there is only
    256 	 * one active cpu after this, and our priority will be too high
    257 	 * for us to be preempted, we're essentially single threaded
    258 	 * from here on out.
    259 	 */
    260 	(void) spl6();
    261 	if (!panicstr) {
    262 		mutex_enter(&cpu_lock);
    263 		pause_cpus(NULL);
    264 		mutex_exit(&cpu_lock);
    265 	}
    266 
    267 	/*
    268 	 * If the system is panicking, the preloaded kernel is valid, and
    269 	 * fastreboot_onpanic has been set, and the system has been up for
    270 	 * longer than fastreboot_onpanic_uptime (default to 10 minutes),
    271 	 * choose Fast Reboot.
    272 	 */
    273 	if (fcn == AD_BOOT && panicstr && newkernel.fi_valid &&
    274 	    fastreboot_onpanic &&
    275 	    (panic_lbolt - lbolt_at_boot) > fastreboot_onpanic_uptime) {
    276 		fcn = AD_FASTREBOOT;
    277 	}
    278 
    279 	/*
    280 	 * Try to quiesce devices.
    281 	 */
    282 	if (is_first_quiesce) {
    283 		/*
    284 		 * Clear is_first_quiesce before calling quiesce_devices()
    285 		 * so that if quiesce_devices() causes panics, it will not
    286 		 * be invoked again.
    287 		 */
    288 		is_first_quiesce = 0;
    289 
    290 		quiesce_active = 1;
    291 		quiesce_devices(ddi_root_node(), &reset_status);
    292 		if (reset_status == -1) {
    293 			if (fcn == AD_FASTREBOOT && !force_fastreboot) {
    294 				prom_printf("Driver(s) not capable of fast "
    295 				    "reboot.\n");
    296 				prom_printf(fallback_str);
    297 				fastreboot_capable = 0;
    298 				fcn = AD_BOOT;
    299 			} else if (fcn != AD_FASTREBOOT)
    300 				fastreboot_capable = 0;
    301 		}
    302 		quiesce_active = 0;
    303 	}
    304 
    305 	/*
    306 	 * Try to reset devices. reset_leaves() should only be called
    307 	 * a) when there are no other threads that could be accessing devices,
    308 	 *    and
    309 	 * b) on a system that's not capable of fast reboot (fastreboot_capable
    310 	 *    being 0), or on a system where quiesce_devices() failed to
    311 	 *    complete (quiesce_active being 1).
    312 	 */
    313 	if (is_first_reset && (!fastreboot_capable || quiesce_active)) {
    314 		/*
    315 		 * Clear is_first_reset before calling reset_devices()
    316 		 * so that if reset_devices() causes panics, it will not
    317 		 * be invoked again.
    318 		 */
    319 		is_first_reset = 0;
    320 		reset_leaves();
    321 	}
    322 
    323 	/* Verify newkernel checksum */
    324 	if (fastreboot_capable && fcn == AD_FASTREBOOT &&
    325 	    fastboot_cksum_verify(&newkernel) != 0) {
    326 		fastreboot_capable = 0;
    327 		prom_printf("Fast reboot: checksum failed for the new "
    328 		    "kernel.\n");
    329 		prom_printf(fallback_str);
    330 	}
    331 
    332 	(void) spl8();
    333 
    334 	if (fastreboot_capable && fcn == AD_FASTREBOOT) {
    335 		/*
    336 		 * psm_shutdown is called within fast_reboot()
    337 		 */
    338 		fast_reboot();
    339 	} else {
    340 		(*psm_shutdownf)(cmd, fcn);
    341 
    342 		if (fcn == AD_HALT || fcn == AD_POWEROFF)
    343 			halt((char *)NULL);
    344 		else
    345 			prom_reboot("");
    346 	}
    347 	/*NOTREACHED*/
    348 }
    349 
    350 /* mdpreboot - may be called prior to mdboot while root fs still mounted */
    351 /*ARGSUSED*/
    352 void
    353 mdpreboot(int cmd, int fcn, char *mdep)
    354 {
    355 	if (fcn == AD_FASTREBOOT && !fastreboot_capable) {
    356 		fcn = AD_BOOT;
    357 #ifdef	__xpv
    358 		cmn_err(CE_WARN, "Fast reboot is not supported on xVM");
    359 #else
    360 		cmn_err(CE_WARN,
    361 		    "Fast reboot is not supported on this platform");
    362 #endif
    363 	}
    364 
    365 	if (fcn == AD_FASTREBOOT) {
    366 		fastboot_load_kernel(mdep);
    367 		if (!newkernel.fi_valid)
    368 			fcn = AD_BOOT;
    369 	}
    370 
    371 	(*psm_preshutdownf)(cmd, fcn);
    372 }
    373 
    374 static void
    375 stop_other_cpus(void)
    376 {
    377 	ulong_t s = clear_int_flag(); /* fast way to keep CPU from changing */
    378 	cpuset_t xcset;
    379 
    380 	CPUSET_ALL_BUT(xcset, CPU->cpu_id);
    381 	xc_priority(0, 0, 0, CPUSET2BV(xcset), (xc_func_t)mach_cpu_halt);
    382 	restore_int_flag(s);
    383 }
    384 
    385 /*
    386  *	Machine dependent abort sequence handling
    387  */
    388 void
    389 abort_sequence_enter(char *msg)
    390 {
    391 	if (abort_enable == 0) {
    392 		if (audit_active)
    393 			audit_enterprom(0);
    394 		return;
    395 	}
    396 	if (audit_active)
    397 		audit_enterprom(1);
    398 	debug_enter(msg);
    399 	if (audit_active)
    400 		audit_exitprom(1);
    401 }
    402 
    403 /*
    404  * Enter debugger.  Called when the user types ctrl-alt-d or whenever
    405  * code wants to enter the debugger and possibly resume later.
    406  */
    407 void
    408 debug_enter(
    409 	char	*msg)		/* message to print, possibly NULL */
    410 {
    411 	if (dtrace_debugger_init != NULL)
    412 		(*dtrace_debugger_init)();
    413 
    414 	if (msg)
    415 		prom_printf("%s\n", msg);
    416 
    417 	if (boothowto & RB_DEBUG)
    418 		kmdb_enter();
    419 
    420 	if (dtrace_debugger_fini != NULL)
    421 		(*dtrace_debugger_fini)();
    422 }
    423 
    424 void
    425 reset(void)
    426 {
    427 	extern	void acpi_reset_system();
    428 #if !defined(__xpv)
    429 	ushort_t *bios_memchk;
    430 
    431 	/*
    432 	 * Can't use psm_map_phys or acpi_reset_system before the hat is
    433 	 * initialized.
    434 	 */
    435 	if (khat_running) {
    436 		bios_memchk = (ushort_t *)psm_map_phys(0x472,
    437 		    sizeof (ushort_t), PROT_READ | PROT_WRITE);
    438 		if (bios_memchk)
    439 			*bios_memchk = 0x1234;	/* bios memory check disable */
    440 
    441 		if (options_dip != NULL &&
    442 		    ddi_prop_exists(DDI_DEV_T_ANY, ddi_root_node(), 0,
    443 		    "efi-systab")) {
    444 			efi_reset();
    445 		}
    446 
    447 		/*
    448 		 * The problem with using stubs is that we can call
    449 		 * acpi_reset_system only after the kernel is up and running.
    450 		 *
    451 		 * We should create a global state to keep track of how far
    452 		 * up the kernel is but for the time being we will depend on
    453 		 * bootops. bootops cleared in startup_end().
    454 		 */
    455 		if (bootops == NULL)
    456 			acpi_reset_system();
    457 	}
    458 
    459 	pc_reset();
    460 #else
    461 	if (IN_XPV_PANIC()) {
    462 		if (khat_running && bootops == NULL) {
    463 			acpi_reset_system();
    464 		}
    465 
    466 		pc_reset();
    467 	}
    468 
    469 	(void) HYPERVISOR_shutdown(SHUTDOWN_reboot);
    470 	panic("HYPERVISOR_shutdown() failed");
    471 #endif
    472 	/*NOTREACHED*/
    473 }
    474 
    475 /*
    476  * Halt the machine and return to the monitor
    477  */
    478 void
    479 halt(char *s)
    480 {
    481 	stop_other_cpus();	/* send stop signal to other CPUs */
    482 	if (s)
    483 		prom_printf("(%s) \n", s);
    484 	prom_exit_to_mon();
    485 	/*NOTREACHED*/
    486 }
    487 
    488 /*
    489  * Initiate interrupt redistribution.
    490  */
    491 void
    492 i_ddi_intr_redist_all_cpus()
    493 {
    494 }
    495 
    496 /*
    497  * XXX These probably ought to live somewhere else
    498  * XXX They are called from mem.c
    499  */
    500 
    501 /*
    502  * Convert page frame number to an OBMEM page frame number
    503  * (i.e. put in the type bits -- zero for this implementation)
    504  */
    505 pfn_t
    506 impl_obmem_pfnum(pfn_t pf)
    507 {
    508 	return (pf);
    509 }
    510 
    511 #ifdef	NM_DEBUG
    512 int nmi_test = 0;	/* checked in intentry.s during clock int */
    513 int nmtest = -1;
    514 nmfunc1(arg, rp)
    515 int	arg;
    516 struct regs *rp;
    517 {
    518 	printf("nmi called with arg = %x, regs = %x\n", arg, rp);
    519 	nmtest += 50;
    520 	if (arg == nmtest) {
    521 		printf("ip = %x\n", rp->r_pc);
    522 		return (1);
    523 	}
    524 	return (0);
    525 }
    526 
    527 #endif
    528 
    529 #include <sys/bootsvcs.h>
    530 
    531 /* Hacked up initialization for initial kernel check out is HERE. */
    532 /* The basic steps are: */
    533 /*	kernel bootfuncs definition/initialization for KADB */
    534 /*	kadb bootfuncs pointer initialization */
    535 /*	putchar/getchar (interrupts disabled) */
    536 
    537 /* kadb bootfuncs pointer initialization */
    538 
    539 int
    540 sysp_getchar()
    541 {
    542 	int i;
    543 	ulong_t s;
    544 
    545 	if (cons_polledio == NULL) {
    546 		/* Uh oh */
    547 		prom_printf("getchar called with no console\n");
    548 		for (;;)
    549 			/* LOOP FOREVER */;
    550 	}
    551 
    552 	s = clear_int_flag();
    553 	i = cons_polledio->cons_polledio_getchar(
    554 	    cons_polledio->cons_polledio_argument);
    555 	restore_int_flag(s);
    556 	return (i);
    557 }
    558 
    559 void
    560 sysp_putchar(int c)
    561 {
    562 	ulong_t s;
    563 
    564 	/*
    565 	 * We have no alternative but to drop the output on the floor.
    566 	 */
    567 	if (cons_polledio == NULL ||
    568 	    cons_polledio->cons_polledio_putchar == NULL)
    569 		return;
    570 
    571 	s = clear_int_flag();
    572 	cons_polledio->cons_polledio_putchar(
    573 	    cons_polledio->cons_polledio_argument, c);
    574 	restore_int_flag(s);
    575 }
    576 
    577 int
    578 sysp_ischar()
    579 {
    580 	int i;
    581 	ulong_t s;
    582 
    583 	if (cons_polledio == NULL ||
    584 	    cons_polledio->cons_polledio_ischar == NULL)
    585 		return (0);
    586 
    587 	s = clear_int_flag();
    588 	i = cons_polledio->cons_polledio_ischar(
    589 	    cons_polledio->cons_polledio_argument);
    590 	restore_int_flag(s);
    591 	return (i);
    592 }
    593 
    594 int
    595 goany(void)
    596 {
    597 	prom_printf("Type any key to continue ");
    598 	(void) prom_getchar();
    599 	prom_printf("\n");
    600 	return (1);
    601 }
    602 
    603 static struct boot_syscalls kern_sysp = {
    604 	sysp_getchar,	/*	unchar	(*getchar)();	7  */
    605 	sysp_putchar,	/*	int	(*putchar)();	8  */
    606 	sysp_ischar,	/*	int	(*ischar)();	9  */
    607 };
    608 
    609 #if defined(__xpv)
    610 int using_kern_polledio;
    611 #endif
    612 
    613 void
    614 kadb_uses_kernel()
    615 {
    616 	/*
    617 	 * This routine is now totally misnamed, since it does not in fact
    618 	 * control kadb's I/O; it only controls the kernel's prom_* I/O.
    619 	 */
    620 	sysp = &kern_sysp;
    621 #if defined(__xpv)
    622 	using_kern_polledio = 1;
    623 #endif
    624 }
    625 
    626 /*
    627  *	the interface to the outside world
    628  */
    629 
    630 /*
    631  * poll_port -- wait for a register to achieve a
    632  *		specific state.  Arguments are a mask of bits we care about,
    633  *		and two sub-masks.  To return normally, all the bits in the
    634  *		first sub-mask must be ON, all the bits in the second sub-
    635  *		mask must be OFF.  If about seconds pass without the register
    636  *		achieving the desired bit configuration, we return 1, else
    637  *		0.
    638  */
    639 int
    640 poll_port(ushort_t port, ushort_t mask, ushort_t onbits, ushort_t offbits)
    641 {
    642 	int i;
    643 	ushort_t maskval;
    644 
    645 	for (i = 500000; i; i--) {
    646 		maskval = inb(port) & mask;
    647 		if (((maskval & onbits) == onbits) &&
    648 		    ((maskval & offbits) == 0))
    649 			return (0);
    650 		drv_usecwait(10);
    651 	}
    652 	return (1);
    653 }
    654 
    655 /*
    656  * set_idle_cpu is called from idle() when a CPU becomes idle.
    657  */
    658 /*LINTED: static unused */
    659 static uint_t last_idle_cpu;
    660 
    661 /*ARGSUSED*/
    662 void
    663 set_idle_cpu(int cpun)
    664 {
    665 	last_idle_cpu = cpun;
    666 	(*psm_set_idle_cpuf)(cpun);
    667 }
    668 
    669 /*
    670  * unset_idle_cpu is called from idle() when a CPU is no longer idle.
    671  */
    672 /*ARGSUSED*/
    673 void
    674 unset_idle_cpu(int cpun)
    675 {
    676 	(*psm_unset_idle_cpuf)(cpun);
    677 }
    678 
    679 /*
    680  * This routine is almost correct now, but not quite.  It still needs the
    681  * equivalent concept of "hres_last_tick", just like on the sparc side.
    682  * The idea is to take a snapshot of the hi-res timer while doing the
    683  * hrestime_adj updates under hres_lock in locore, so that the small
    684  * interval between interrupt assertion and interrupt processing is
    685  * accounted for correctly.  Once we have this, the code below should
    686  * be modified to subtract off hres_last_tick rather than hrtime_base.
    687  *
    688  * I'd have done this myself, but I don't have source to all of the
    689  * vendor-specific hi-res timer routines (grrr...).  The generic hook I
    690  * need is something like "gethrtime_unlocked()", which would be just like
    691  * gethrtime() but would assume that you're already holding CLOCK_LOCK().
    692  * This is what the GET_HRTIME() macro is for on sparc (although it also
    693  * serves the function of making time available without a function call
    694  * so you don't take a register window overflow while traps are disabled).
    695  */
    696 void
    697 pc_gethrestime(timestruc_t *tp)
    698 {
    699 	int lock_prev;
    700 	timestruc_t now;
    701 	int nslt;		/* nsec since last tick */
    702 	int adj;		/* amount of adjustment to apply */
    703 
    704 loop:
    705 	lock_prev = hres_lock;
    706 	now = hrestime;
    707 	nslt = (int)(gethrtime() - hres_last_tick);
    708 	if (nslt < 0) {
    709 		/*
    710 		 * nslt < 0 means a tick came between sampling
    711 		 * gethrtime() and hres_last_tick; restart the loop
    712 		 */
    713 
    714 		goto loop;
    715 	}
    716 	now.tv_nsec += nslt;
    717 	if (hrestime_adj != 0) {
    718 		if (hrestime_adj > 0) {
    719 			adj = (nslt >> ADJ_SHIFT);
    720 			if (adj > hrestime_adj)
    721 				adj = (int)hrestime_adj;
    722 		} else {
    723 			adj = -(nslt >> ADJ_SHIFT);
    724 			if (adj < hrestime_adj)
    725 				adj = (int)hrestime_adj;
    726 		}
    727 		now.tv_nsec += adj;
    728 	}
    729 	while ((unsigned long)now.tv_nsec >= NANOSEC) {
    730 
    731 		/*
    732 		 * We might have a large adjustment or have been in the
    733 		 * debugger for a long time; take care of (at most) four
    734 		 * of those missed seconds (tv_nsec is 32 bits, so
    735 		 * anything >4s will be wrapping around).  However,
    736 		 * anything more than 2 seconds out of sync will trigger
    737 		 * timedelta from clock() to go correct the time anyway,
    738 		 * so do what we can, and let the big crowbar do the
    739 		 * rest.  A similar correction while loop exists inside
    740 		 * hres_tick(); in all cases we'd like tv_nsec to
    741 		 * satisfy 0 <= tv_nsec < NANOSEC to avoid confusing
    742 		 * user processes, but if tv_sec's a little behind for a
    743 		 * little while, that's OK; time still monotonically
    744 		 * increases.
    745 		 */
    746 
    747 		now.tv_nsec -= NANOSEC;
    748 		now.tv_sec++;
    749 	}
    750 	if ((hres_lock & ~1) != lock_prev)
    751 		goto loop;
    752 
    753 	*tp = now;
    754 }
    755 
    756 void
    757 gethrestime_lasttick(timespec_t *tp)
    758 {
    759 	int s;
    760 
    761 	s = hr_clock_lock();
    762 	*tp = hrestime;
    763 	hr_clock_unlock(s);
    764 }
    765 
    766 time_t
    767 gethrestime_sec(void)
    768 {
    769 	timestruc_t now;
    770 
    771 	gethrestime(&now);
    772 	return (now.tv_sec);
    773 }
    774 
    775 /*
    776  * Initialize a kernel thread's stack
    777  */
    778 
    779 caddr_t
    780 thread_stk_init(caddr_t stk)
    781 {
    782 	ASSERT(((uintptr_t)stk & (STACK_ALIGN - 1)) == 0);
    783 	return (stk - SA(MINFRAME));
    784 }
    785 
    786 /*
    787  * Initialize lwp's kernel stack.
    788  */
    789 
    790 #ifdef TRAPTRACE
    791 /*
    792  * There's a tricky interdependency here between use of sysenter and
    793  * TRAPTRACE which needs recording to avoid future confusion (this is
    794  * about the third time I've re-figured this out ..)
    795  *
    796  * Here's how debugging lcall works with TRAPTRACE.
    797  *
    798  * 1 We're in userland with a breakpoint on the lcall instruction.
    799  * 2 We execute the instruction - the instruction pushes the userland
    800  *   %ss, %esp, %efl, %cs, %eip on the stack and zips into the kernel
    801  *   via the call gate.
    802  * 3 The hardware raises a debug trap in kernel mode, the hardware
    803  *   pushes %efl, %cs, %eip and gets to dbgtrap via the idt.
    804  * 4 dbgtrap pushes the error code and trapno and calls cmntrap
    805  * 5 cmntrap finishes building a trap frame
    806  * 6 The TRACE_REGS macros in cmntrap copy a REGSIZE worth chunk
    807  *   off the stack into the traptrace buffer.
    808  *
    809  * This means that the traptrace buffer contains the wrong values in
    810  * %esp and %ss, but everything else in there is correct.
    811  *
    812  * Here's how debugging sysenter works with TRAPTRACE.
    813  *
    814  * a We're in userland with a breakpoint on the sysenter instruction.
    815  * b We execute the instruction - the instruction pushes -nothing-
    816  *   on the stack, but sets %cs, %eip, %ss, %esp to prearranged
    817  *   values to take us to sys_sysenter, at the top of the lwp's
    818  *   stack.
    819  * c goto 3
    820  *
    821  * At this point, because we got into the kernel without the requisite
    822  * five pushes on the stack, if we didn't make extra room, we'd
    823  * end up with the TRACE_REGS macro fetching the saved %ss and %esp
    824  * values from negative (unmapped) stack addresses -- which really bites.
    825  * That's why we do the '-= 8' below.
    826  *
    827  * XXX	Note that reading "up" lwp0's stack works because t0 is declared
    828  *	right next to t0stack in locore.s
    829  */
    830 #endif
    831 
    832 caddr_t
    833 lwp_stk_init(klwp_t *lwp, caddr_t stk)
    834 {
    835 	caddr_t oldstk;
    836 	struct pcb *pcb = &lwp->lwp_pcb;
    837 
    838 	oldstk = stk;
    839 	stk -= SA(sizeof (struct regs) + SA(MINFRAME));
    840 #ifdef TRAPTRACE
    841 	stk -= 2 * sizeof (greg_t); /* space for phony %ss:%sp (see above) */
    842 #endif
    843 	stk = (caddr_t)((uintptr_t)stk & ~(STACK_ALIGN - 1ul));
    844 	bzero(stk, oldstk - stk);
    845 	lwp->lwp_regs = (void *)(stk + SA(MINFRAME));
    846 
    847 	/*
    848 	 * Arrange that the virtualized %fs and %gs GDT descriptors
    849 	 * have a well-defined initial state (present, ring 3
    850 	 * and of type data).
    851 	 */
    852 #if defined(__amd64)
    853 	if (lwp_getdatamodel(lwp) == DATAMODEL_NATIVE)
    854 		pcb->pcb_fsdesc = pcb->pcb_gsdesc = zero_udesc;
    855 	else
    856 		pcb->pcb_fsdesc = pcb->pcb_gsdesc = zero_u32desc;
    857 #elif defined(__i386)
    858 	pcb->pcb_fsdesc = pcb->pcb_gsdesc = zero_udesc;
    859 #endif	/* __i386 */
    860 	lwp_installctx(lwp);
    861 	return (stk);
    862 }
    863 
    864 /*ARGSUSED*/
    865 void
    866 lwp_stk_fini(klwp_t *lwp)
    867 {}
    868 
    869 /*
    870  * If we're not the panic CPU, we wait in panic_idle for reboot.
    871  */
    872 void
    873 panic_idle(void)
    874 {
    875 	splx(ipltospl(CLOCK_LEVEL));
    876 	(void) setjmp(&curthread->t_pcb);
    877 
    878 	dumpsys_helper();
    879 
    880 #ifndef __xpv
    881 	for (;;)
    882 		i86_halt();
    883 #else
    884 	for (;;)
    885 		;
    886 #endif
    887 }
    888 
    889 /*
    890  * Stop the other CPUs by cross-calling them and forcing them to enter
    891  * the panic_idle() loop above.
    892  */
    893 /*ARGSUSED*/
    894 void
    895 panic_stopcpus(cpu_t *cp, kthread_t *t, int spl)
    896 {
    897 	processorid_t i;
    898 	cpuset_t xcset;
    899 
    900 	/*
    901 	 * In the case of a Xen panic, the hypervisor has already stopped
    902 	 * all of the CPUs.
    903 	 */
    904 	if (!IN_XPV_PANIC()) {
    905 		(void) splzs();
    906 
    907 		CPUSET_ALL_BUT(xcset, cp->cpu_id);
    908 		xc_priority(0, 0, 0, CPUSET2BV(xcset), (xc_func_t)panic_idle);
    909 	}
    910 
    911 	for (i = 0; i < NCPU; i++) {
    912 		if (i != cp->cpu_id && cpu[i] != NULL &&
    913 		    (cpu[i]->cpu_flags & CPU_EXISTS))
    914 			cpu[i]->cpu_flags |= CPU_QUIESCED;
    915 	}
    916 }
    917 
    918 /*
    919  * Platform callback following each entry to panicsys().
    920  */
    921 /*ARGSUSED*/
    922 void
    923 panic_enter_hw(int spl)
    924 {
    925 	/* Nothing to do here */
    926 }
    927 
    928 /*
    929  * Platform-specific code to execute after panicstr is set: we invoke
    930  * the PSM entry point to indicate that a panic has occurred.
    931  */
    932 /*ARGSUSED*/
    933 void
    934 panic_quiesce_hw(panic_data_t *pdp)
    935 {
    936 	psm_notifyf(PSM_PANIC_ENTER);
    937 
    938 	cmi_panic_callback();
    939 
    940 #ifdef	TRAPTRACE
    941 	/*
    942 	 * Turn off TRAPTRACE
    943 	 */
    944 	TRAPTRACE_FREEZE;
    945 #endif	/* TRAPTRACE */
    946 }
    947 
    948 /*
    949  * Platform callback prior to writing crash dump.
    950  */
    951 /*ARGSUSED*/
    952 void
    953 panic_dump_hw(int spl)
    954 {
    955 	/* Nothing to do here */
    956 }
    957 
    958 void *
    959 plat_traceback(void *fpreg)
    960 {
    961 #ifdef __xpv
    962 	if (IN_XPV_PANIC())
    963 		return (xpv_traceback(fpreg));
    964 #endif
    965 	return (fpreg);
    966 }
    967 
    968 /*ARGSUSED*/
    969 void
    970 plat_tod_fault(enum tod_fault_type tod_bad)
    971 {}
    972 
    973 /*ARGSUSED*/
    974 int
    975 blacklist(int cmd, const char *scheme, nvlist_t *fmri, const char *class)
    976 {
    977 	return (ENOTSUP);
    978 }
    979 
    980 /*
    981  * The underlying console output routines are protected by raising IPL in case
    982  * we are still calling into the early boot services.  Once we start calling
    983  * the kernel console emulator, it will disable interrupts completely during
    984  * character rendering (see sysp_putchar, for example).  Refer to the comments
    985  * and code in common/os/console.c for more information on these callbacks.
    986  */
    987 /*ARGSUSED*/
    988 int
    989 console_enter(int busy)
    990 {
    991 	return (splzs());
    992 }
    993 
    994 /*ARGSUSED*/
    995 void
    996 console_exit(int busy, int spl)
    997 {
    998 	splx(spl);
    999 }
   1000 
   1001 /*
   1002  * Allocate a region of virtual address space, unmapped.
   1003  * Stubbed out except on sparc, at least for now.
   1004  */
   1005 /*ARGSUSED*/
   1006 void *
   1007 boot_virt_alloc(void *addr, size_t size)
   1008 {
   1009 	return (addr);
   1010 }
   1011 
   1012 volatile unsigned long	tenmicrodata;
   1013 
   1014 void
   1015 tenmicrosec(void)
   1016 {
   1017 	extern int gethrtime_hires;
   1018 
   1019 	if (gethrtime_hires) {
   1020 		hrtime_t start, end;
   1021 		start = end =  gethrtime();
   1022 		while ((end - start) < (10 * (NANOSEC / MICROSEC))) {
   1023 			SMT_PAUSE();
   1024 			end = gethrtime();
   1025 		}
   1026 	} else {
   1027 #if defined(__xpv)
   1028 		hrtime_t newtime;
   1029 
   1030 		newtime = xpv_gethrtime() + 10000; /* now + 10 us */
   1031 		while (xpv_gethrtime() < newtime)
   1032 			SMT_PAUSE();
   1033 #else	/* __xpv */
   1034 		int i;
   1035 
   1036 		/*
   1037 		 * Artificial loop to induce delay.
   1038 		 */
   1039 		for (i = 0; i < microdata; i++)
   1040 			tenmicrodata = microdata;
   1041 #endif	/* __xpv */
   1042 	}
   1043 }
   1044 
   1045 /*
   1046  * get_cpu_mstate() is passed an array of timestamps, NCMSTATES
   1047  * long, and it fills in the array with the time spent on cpu in
   1048  * each of the mstates, where time is returned in nsec.
   1049  *
   1050  * No guarantee is made that the returned values in times[] will
   1051  * monotonically increase on sequential calls, although this will
   1052  * be true in the long run. Any such guarantee must be handled by
   1053  * the caller, if needed. This can happen if we fail to account
   1054  * for elapsed time due to a generation counter conflict, yet we
   1055  * did account for it on a prior call (see below).
   1056  *
   1057  * The complication is that the cpu in question may be updating
   1058  * its microstate at the same time that we are reading it.
   1059  * Because the microstate is only updated when the CPU's state
   1060  * changes, the values in cpu_intracct[] can be indefinitely out
   1061  * of date. To determine true current values, it is necessary to
   1062  * compare the current time with cpu_mstate_start, and add the
   1063  * difference to times[cpu_mstate].
   1064  *
   1065  * This can be a problem if those values are changing out from
   1066  * under us. Because the code path in new_cpu_mstate() is
   1067  * performance critical, we have not added a lock to it. Instead,
   1068  * we have added a generation counter. Before beginning
   1069  * modifications, the counter is set to 0. After modifications,
   1070  * it is set to the old value plus one.
   1071  *
   1072  * get_cpu_mstate() will not consider the values of cpu_mstate
   1073  * and cpu_mstate_start to be usable unless the value of
   1074  * cpu_mstate_gen is both non-zero and unchanged, both before and
   1075  * after reading the mstate information. Note that we must
   1076  * protect against out-of-order loads around accesses to the
   1077  * generation counter. Also, this is a best effort approach in
   1078  * that we do not retry should the counter be found to have
   1079  * changed.
   1080  *
   1081  * cpu_intracct[] is used to identify time spent in each CPU
   1082  * mstate while handling interrupts. Such time should be reported
   1083  * against system time, and so is subtracted out from its
   1084  * corresponding cpu_acct[] time and added to
   1085  * cpu_acct[CMS_SYSTEM].
   1086  */
   1087 
   1088 void
   1089 get_cpu_mstate(cpu_t *cpu, hrtime_t *times)
   1090 {
   1091 	int i;
   1092 	hrtime_t now, start;
   1093 	uint16_t gen;
   1094 	uint16_t state;
   1095 	hrtime_t intracct[NCMSTATES];
   1096 
   1097 	/*
   1098 	 * Load all volatile state under the protection of membar.
   1099 	 * cpu_acct[cpu_mstate] must be loaded to avoid double counting
   1100 	 * of (now - cpu_mstate_start) by a change in CPU mstate that
   1101 	 * arrives after we make our last check of cpu_mstate_gen.
   1102 	 */
   1103 
   1104 	now = gethrtime_unscaled();
   1105 	gen = cpu->cpu_mstate_gen;
   1106 
   1107 	membar_consumer();	/* guarantee load ordering */
   1108 	start = cpu->cpu_mstate_start;
   1109 	state = cpu->cpu_mstate;
   1110 	for (i = 0; i < NCMSTATES; i++) {
   1111 		intracct[i] = cpu->cpu_intracct[i];
   1112 		times[i] = cpu->cpu_acct[i];
   1113 	}
   1114 	membar_consumer();	/* guarantee load ordering */
   1115 
   1116 	if (gen != 0 && gen == cpu->cpu_mstate_gen && now > start)
   1117 		times[state] += now - start;
   1118 
   1119 	for (i = 0; i < NCMSTATES; i++) {
   1120 		if (i == CMS_SYSTEM)
   1121 			continue;
   1122 		times[i] -= intracct[i];
   1123 		if (times[i] < 0) {
   1124 			intracct[i] += times[i];
   1125 			times[i] = 0;
   1126 		}
   1127 		times[CMS_SYSTEM] += intracct[i];
   1128 		scalehrtime(&times[i]);
   1129 	}
   1130 	scalehrtime(&times[CMS_SYSTEM]);
   1131 }
   1132 
   1133 /*
   1134  * This is a version of the rdmsr instruction that allows
   1135  * an error code to be returned in the case of failure.
   1136  */
   1137 int
   1138 checked_rdmsr(uint_t msr, uint64_t *value)
   1139 {
   1140 	if ((x86_feature & X86_MSR) == 0)
   1141 		return (ENOTSUP);
   1142 	*value = rdmsr(msr);
   1143 	return (0);
   1144 }
   1145 
   1146 /*
   1147  * This is a version of the wrmsr instruction that allows
   1148  * an error code to be returned in the case of failure.
   1149  */
   1150 int
   1151 checked_wrmsr(uint_t msr, uint64_t value)
   1152 {
   1153 	if ((x86_feature & X86_MSR) == 0)
   1154 		return (ENOTSUP);
   1155 	wrmsr(msr, value);
   1156 	return (0);
   1157 }
   1158 
   1159 /*
   1160  * The mem driver's usual method of using hat_devload() to establish a
   1161  * temporary mapping will not work for foreign pages mapped into this
   1162  * domain or for the special hypervisor-provided pages.  For the foreign
   1163  * pages, we often don't know which domain owns them, so we can't ask the
   1164  * hypervisor to set up a new mapping.  For the other pages, we don't have
   1165  * a pfn, so we can't create a new PTE.  For these special cases, we do a
   1166  * direct uiomove() from the existing kernel virtual address.
   1167  */
   1168 /*ARGSUSED*/
   1169 int
   1170 plat_mem_do_mmio(struct uio *uio, enum uio_rw rw)
   1171 {
   1172 #if defined(__xpv)
   1173 	void *va = (void *)(uintptr_t)uio->uio_loffset;
   1174 	off_t pageoff = uio->uio_loffset & PAGEOFFSET;
   1175 	size_t nbytes = MIN((size_t)(PAGESIZE - pageoff),
   1176 	    (size_t)uio->uio_iov->iov_len);
   1177 
   1178 	if ((rw == UIO_READ &&
   1179 	    (va == HYPERVISOR_shared_info || va == xen_info)) ||
   1180 	    (pfn_is_foreign(hat_getpfnum(kas.a_hat, va))))
   1181 		return (uiomove(va, nbytes, rw, uio));
   1182 #endif
   1183 	return (ENOTSUP);
   1184 }
   1185 
   1186 pgcnt_t
   1187 num_phys_pages()
   1188 {
   1189 	pgcnt_t npages = 0;
   1190 	struct memlist *mp;
   1191 
   1192 #if defined(__xpv)
   1193 	if (DOMAIN_IS_INITDOMAIN(xen_info))
   1194 		return (xpv_nr_phys_pages());
   1195 #endif /* __xpv */
   1196 
   1197 	for (mp = phys_install; mp != NULL; mp = mp->next)
   1198 		npages += mp->size >> PAGESHIFT;
   1199 
   1200 	return (npages);
   1201 }
   1202 
   1203 /* cpu threshold for compressed dumps */
   1204 #ifdef _LP64
   1205 uint_t dump_plat_mincpu = DUMP_PLAT_X86_64_MINCPU;
   1206 #else
   1207 uint_t dump_plat_mincpu = DUMP_PLAT_X86_32_MINCPU;
   1208 #endif
   1209 
   1210 int
   1211 dump_plat_addr()
   1212 {
   1213 #ifdef __xpv
   1214 	pfn_t pfn = mmu_btop(xen_info->shared_info) | PFN_IS_FOREIGN_MFN;
   1215 	mem_vtop_t mem_vtop;
   1216 	int cnt;
   1217 
   1218 	/*
   1219 	 * On the hypervisor, we want to dump the page with shared_info on it.
   1220 	 */
   1221 	if (!IN_XPV_PANIC()) {
   1222 		mem_vtop.m_as = &kas;
   1223 		mem_vtop.m_va = HYPERVISOR_shared_info;
   1224 		mem_vtop.m_pfn = pfn;
   1225 		dumpvp_write(&mem_vtop, sizeof (mem_vtop_t));
   1226 		cnt = 1;
   1227 	} else {
   1228 		cnt = dump_xpv_addr();
   1229 	}
   1230 	return (cnt);
   1231 #else
   1232 	return (0);
   1233 #endif
   1234 }
   1235 
   1236 void
   1237 dump_plat_pfn()
   1238 {
   1239 #ifdef __xpv
   1240 	pfn_t pfn = mmu_btop(xen_info->shared_info) | PFN_IS_FOREIGN_MFN;
   1241 
   1242 	if (!IN_XPV_PANIC())
   1243 		dumpvp_write(&pfn, sizeof (pfn));
   1244 	else
   1245 		dump_xpv_pfn();
   1246 #endif
   1247 }
   1248 
   1249 /*ARGSUSED*/
   1250 int
   1251 dump_plat_data(void *dump_cbuf)
   1252 {
   1253 #ifdef __xpv
   1254 	uint32_t csize;
   1255 	int cnt;
   1256 
   1257 	if (!IN_XPV_PANIC()) {
   1258 		csize = (uint32_t)compress(HYPERVISOR_shared_info, dump_cbuf,
   1259 		    PAGESIZE);
   1260 		dumpvp_write(&csize, sizeof (uint32_t));
   1261 		dumpvp_write(dump_cbuf, csize);
   1262 		cnt = 1;
   1263 	} else {
   1264 		cnt = dump_xpv_data(dump_cbuf);
   1265 	}
   1266 	return (cnt);
   1267 #else
   1268 	return (0);
   1269 #endif
   1270 }
   1271 
   1272 /*
   1273  * Calculates a linear address, given the CS selector and PC values
   1274  * by looking up the %cs selector process's LDT or the CPU's GDT.
   1275  * proc->p_ldtlock must be held across this call.
   1276  */
   1277 int
   1278 linear_pc(struct regs *rp, proc_t *p, caddr_t *linearp)
   1279 {
   1280 	user_desc_t	*descrp;
   1281 	caddr_t		baseaddr;
   1282 	uint16_t	idx = SELTOIDX(rp->r_cs);
   1283 
   1284 	ASSERT(rp->r_cs <= 0xFFFF);
   1285 	ASSERT(MUTEX_HELD(&p->p_ldtlock));
   1286 
   1287 	if (SELISLDT(rp->r_cs)) {
   1288 		/*
   1289 		 * Currently 64 bit processes cannot have private LDTs.
   1290 		 */
   1291 		ASSERT(p->p_model != DATAMODEL_LP64);
   1292 
   1293 		if (p->p_ldt == NULL)
   1294 			return (-1);
   1295 
   1296 		descrp = &p->p_ldt[idx];
   1297 		baseaddr = (caddr_t)(uintptr_t)USEGD_GETBASE(descrp);
   1298 
   1299 		/*
   1300 		 * Calculate the linear address (wraparound is not only ok,
   1301 		 * it's expected behavior).  The cast to uint32_t is because
   1302 		 * LDT selectors are only allowed in 32-bit processes.
   1303 		 */
   1304 		*linearp = (caddr_t)(uintptr_t)(uint32_t)((uintptr_t)baseaddr +
   1305 		    rp->r_pc);
   1306 	} else {
   1307 #ifdef DEBUG
   1308 		descrp = &CPU->cpu_gdt[idx];
   1309 		baseaddr = (caddr_t)(uintptr_t)USEGD_GETBASE(descrp);
   1310 		/* GDT-based descriptors' base addresses should always be 0 */
   1311 		ASSERT(baseaddr == 0);
   1312 #endif
   1313 		*linearp = (caddr_t)(uintptr_t)rp->r_pc;
   1314 	}
   1315 
   1316 	return (0);
   1317 }
   1318 
   1319 /*
   1320  * The implementation of dtrace_linear_pc is similar to the that of
   1321  * linear_pc, above, but here we acquire p_ldtlock before accessing
   1322  * p_ldt.  This implementation is used by the pid provider; we prefix
   1323  * it with "dtrace_" to avoid inducing spurious tracing events.
   1324  */
   1325 int
   1326 dtrace_linear_pc(struct regs *rp, proc_t *p, caddr_t *linearp)
   1327 {
   1328 	user_desc_t	*descrp;
   1329 	caddr_t		baseaddr;
   1330 	uint16_t	idx = SELTOIDX(rp->r_cs);
   1331 
   1332 	ASSERT(rp->r_cs <= 0xFFFF);
   1333 
   1334 	if (SELISLDT(rp->r_cs)) {
   1335 		/*
   1336 		 * Currently 64 bit processes cannot have private LDTs.
   1337 		 */
   1338 		ASSERT(p->p_model != DATAMODEL_LP64);
   1339 
   1340 		mutex_enter(&p->p_ldtlock);
   1341 		if (p->p_ldt == NULL) {
   1342 			mutex_exit(&p->p_ldtlock);
   1343 			return (-1);
   1344 		}
   1345 		descrp = &p->p_ldt[idx];
   1346 		baseaddr = (caddr_t)(uintptr_t)USEGD_GETBASE(descrp);
   1347 		mutex_exit(&p->p_ldtlock);
   1348 
   1349 		/*
   1350 		 * Calculate the linear address (wraparound is not only ok,
   1351 		 * it's expected behavior).  The cast to uint32_t is because
   1352 		 * LDT selectors are only allowed in 32-bit processes.
   1353 		 */
   1354 		*linearp = (caddr_t)(uintptr_t)(uint32_t)((uintptr_t)baseaddr +
   1355 		    rp->r_pc);
   1356 	} else {
   1357 #ifdef DEBUG
   1358 		descrp = &CPU->cpu_gdt[idx];
   1359 		baseaddr = (caddr_t)(uintptr_t)USEGD_GETBASE(descrp);
   1360 		/* GDT-based descriptors' base addresses should always be 0 */
   1361 		ASSERT(baseaddr == 0);
   1362 #endif
   1363 		*linearp = (caddr_t)(uintptr_t)rp->r_pc;
   1364 	}
   1365 
   1366 	return (0);
   1367 }
   1368