xref: /illumos-gate/usr/src/uts/i86pc/os/mp_startup.c (revision b52a336e0ccd9ef29cd11bb3c7e530788483ee04)
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 (c) 1992, 2010, Oracle and/or its affiliates. All rights reserved.
24  */
25 /*
26  * Copyright (c) 2010, Intel Corporation.
27  * All rights reserved.
28  */
29 
30 #include <sys/types.h>
31 #include <sys/thread.h>
32 #include <sys/cpuvar.h>
33 #include <sys/cpu.h>
34 #include <sys/t_lock.h>
35 #include <sys/param.h>
36 #include <sys/proc.h>
37 #include <sys/disp.h>
38 #include <sys/class.h>
39 #include <sys/cmn_err.h>
40 #include <sys/debug.h>
41 #include <sys/note.h>
42 #include <sys/asm_linkage.h>
43 #include <sys/x_call.h>
44 #include <sys/systm.h>
45 #include <sys/var.h>
46 #include <sys/vtrace.h>
47 #include <vm/hat.h>
48 #include <vm/as.h>
49 #include <vm/seg_kmem.h>
50 #include <vm/seg_kp.h>
51 #include <sys/segments.h>
52 #include <sys/kmem.h>
53 #include <sys/stack.h>
54 #include <sys/smp_impldefs.h>
55 #include <sys/x86_archext.h>
56 #include <sys/machsystm.h>
57 #include <sys/traptrace.h>
58 #include <sys/clock.h>
59 #include <sys/cpc_impl.h>
60 #include <sys/pg.h>
61 #include <sys/cmt.h>
62 #include <sys/dtrace.h>
63 #include <sys/archsystm.h>
64 #include <sys/fp.h>
65 #include <sys/reboot.h>
66 #include <sys/kdi_machimpl.h>
67 #include <vm/hat_i86.h>
68 #include <vm/vm_dep.h>
69 #include <sys/memnode.h>
70 #include <sys/pci_cfgspace.h>
71 #include <sys/mach_mmu.h>
72 #include <sys/sysmacros.h>
73 #if defined(__xpv)
74 #include <sys/hypervisor.h>
75 #endif
76 #include <sys/cpu_module.h>
77 
78 struct cpu	cpus[1];			/* CPU data */
79 struct cpu	*cpu[NCPU] = {&cpus[0]};	/* pointers to all CPUs */
80 struct cpu	*cpu_free_list;			/* list for released CPUs */
81 cpu_core_t	cpu_core[NCPU];			/* cpu_core structures */
82 
83 #define	cpu_next_free	cpu_prev
84 
85 /*
86  * Useful for disabling MP bring-up on a MP capable system.
87  */
88 int use_mp = 1;
89 
90 /*
91  * to be set by a PSM to indicate what cpus
92  * are sitting around on the system.
93  */
94 cpuset_t mp_cpus;
95 
96 /*
97  * This variable is used by the hat layer to decide whether or not
98  * critical sections are needed to prevent race conditions.  For sun4m,
99  * this variable is set once enough MP initialization has been done in
100  * order to allow cross calls.
101  */
102 int flushes_require_xcalls;
103 
104 cpuset_t cpu_ready_set;		/* initialized in startup() */
105 
106 static void mp_startup_boot(void);
107 static void mp_startup_hotplug(void);
108 
109 static void cpu_sep_enable(void);
110 static void cpu_sep_disable(void);
111 static void cpu_asysc_enable(void);
112 static void cpu_asysc_disable(void);
113 
114 /*
115  * Init CPU info - get CPU type info for processor_info system call.
116  */
117 void
118 init_cpu_info(struct cpu *cp)
119 {
120 	processor_info_t *pi = &cp->cpu_type_info;
121 
122 	/*
123 	 * Get clock-frequency property for the CPU.
124 	 */
125 	pi->pi_clock = cpu_freq;
126 
127 	/*
128 	 * Current frequency in Hz.
129 	 */
130 	cp->cpu_curr_clock = cpu_freq_hz;
131 
132 	/*
133 	 * Supported frequencies.
134 	 */
135 	if (cp->cpu_supp_freqs == NULL) {
136 		cpu_set_supp_freqs(cp, NULL);
137 	}
138 
139 	(void) strcpy(pi->pi_processor_type, "i386");
140 	if (fpu_exists)
141 		(void) strcpy(pi->pi_fputypes, "i387 compatible");
142 
143 	cp->cpu_idstr = kmem_zalloc(CPU_IDSTRLEN, KM_SLEEP);
144 	cp->cpu_brandstr = kmem_zalloc(CPU_IDSTRLEN, KM_SLEEP);
145 
146 	/*
147 	 * If called for the BSP, cp is equal to current CPU.
148 	 * For non-BSPs, cpuid info of cp is not ready yet, so use cpuid info
149 	 * of current CPU as default values for cpu_idstr and cpu_brandstr.
150 	 * They will be corrected in mp_startup_common() after cpuid_pass1()
151 	 * has been invoked on target CPU.
152 	 */
153 	(void) cpuid_getidstr(CPU, cp->cpu_idstr, CPU_IDSTRLEN);
154 	(void) cpuid_getbrandstr(CPU, cp->cpu_brandstr, CPU_IDSTRLEN);
155 }
156 
157 /*
158  * Configure syscall support on this CPU.
159  */
160 /*ARGSUSED*/
161 void
162 init_cpu_syscall(struct cpu *cp)
163 {
164 	kpreempt_disable();
165 
166 #if defined(__amd64)
167 	if (is_x86_feature(x86_featureset, X86FSET_MSR) &&
168 	    is_x86_feature(x86_featureset, X86FSET_ASYSC)) {
169 
170 #if !defined(__lint)
171 		/*
172 		 * The syscall instruction imposes a certain ordering on
173 		 * segment selectors, so we double-check that ordering
174 		 * here.
175 		 */
176 		ASSERT(KDS_SEL == KCS_SEL + 8);
177 		ASSERT(UDS_SEL == U32CS_SEL + 8);
178 		ASSERT(UCS_SEL == U32CS_SEL + 16);
179 #endif
180 		/*
181 		 * Turn syscall/sysret extensions on.
182 		 */
183 		cpu_asysc_enable();
184 
185 		/*
186 		 * Program the magic registers ..
187 		 */
188 		wrmsr(MSR_AMD_STAR,
189 		    ((uint64_t)(U32CS_SEL << 16 | KCS_SEL)) << 32);
190 		wrmsr(MSR_AMD_LSTAR, (uint64_t)(uintptr_t)sys_syscall);
191 		wrmsr(MSR_AMD_CSTAR, (uint64_t)(uintptr_t)sys_syscall32);
192 
193 		/*
194 		 * This list of flags is masked off the incoming
195 		 * %rfl when we enter the kernel.
196 		 */
197 		wrmsr(MSR_AMD_SFMASK, (uint64_t)(uintptr_t)(PS_IE | PS_T));
198 	}
199 #endif
200 
201 	/*
202 	 * On 32-bit kernels, we use sysenter/sysexit because it's too
203 	 * hard to use syscall/sysret, and it is more portable anyway.
204 	 *
205 	 * On 64-bit kernels on Nocona machines, the 32-bit syscall
206 	 * variant isn't available to 32-bit applications, but sysenter is.
207 	 */
208 	if (is_x86_feature(x86_featureset, X86FSET_MSR) &&
209 	    is_x86_feature(x86_featureset, X86FSET_SEP)) {
210 
211 #if !defined(__lint)
212 		/*
213 		 * The sysenter instruction imposes a certain ordering on
214 		 * segment selectors, so we double-check that ordering
215 		 * here. See "sysenter" in Intel document 245471-012, "IA-32
216 		 * Intel Architecture Software Developer's Manual Volume 2:
217 		 * Instruction Set Reference"
218 		 */
219 		ASSERT(KDS_SEL == KCS_SEL + 8);
220 
221 		ASSERT32(UCS_SEL == ((KCS_SEL + 16) | 3));
222 		ASSERT32(UDS_SEL == UCS_SEL + 8);
223 
224 		ASSERT64(U32CS_SEL == ((KCS_SEL + 16) | 3));
225 		ASSERT64(UDS_SEL == U32CS_SEL + 8);
226 #endif
227 
228 		cpu_sep_enable();
229 
230 		/*
231 		 * resume() sets this value to the base of the threads stack
232 		 * via a context handler.
233 		 */
234 		wrmsr(MSR_INTC_SEP_ESP, 0);
235 		wrmsr(MSR_INTC_SEP_EIP, (uint64_t)(uintptr_t)sys_sysenter);
236 	}
237 
238 	kpreempt_enable();
239 }
240 
241 /*
242  * Multiprocessor initialization.
243  *
244  * Allocate and initialize the cpu structure, TRAPTRACE buffer, and the
245  * startup and idle threads for the specified CPU.
246  * Parameter boot is true for boot time operations and is false for CPU
247  * DR operations.
248  */
249 static struct cpu *
250 mp_cpu_configure_common(int cpun, boolean_t boot)
251 {
252 	struct cpu *cp;
253 	kthread_id_t tp;
254 	caddr_t	sp;
255 	proc_t *procp;
256 #if !defined(__xpv)
257 	extern int idle_cpu_prefer_mwait;
258 	extern void cpu_idle_mwait();
259 #endif
260 	extern void idle();
261 	extern void cpu_idle();
262 
263 #ifdef TRAPTRACE
264 	trap_trace_ctl_t *ttc = &trap_trace_ctl[cpun];
265 #endif
266 
267 	ASSERT(MUTEX_HELD(&cpu_lock));
268 	ASSERT(cpun < NCPU && cpu[cpun] == NULL);
269 
270 	if (cpu_free_list == NULL) {
271 		cp = kmem_zalloc(sizeof (*cp), KM_SLEEP);
272 	} else {
273 		cp = cpu_free_list;
274 		cpu_free_list = cp->cpu_next_free;
275 	}
276 
277 	cp->cpu_m.mcpu_istamp = cpun << 16;
278 
279 	/* Create per CPU specific threads in the process p0. */
280 	procp = &p0;
281 
282 	/*
283 	 * Initialize the dispatcher first.
284 	 */
285 	disp_cpu_init(cp);
286 
287 	cpu_vm_data_init(cp);
288 
289 	/*
290 	 * Allocate and initialize the startup thread for this CPU.
291 	 * Interrupt and process switch stacks get allocated later
292 	 * when the CPU starts running.
293 	 */
294 	tp = thread_create(NULL, 0, NULL, NULL, 0, procp,
295 	    TS_STOPPED, maxclsyspri);
296 
297 	/*
298 	 * Set state to TS_ONPROC since this thread will start running
299 	 * as soon as the CPU comes online.
300 	 *
301 	 * All the other fields of the thread structure are setup by
302 	 * thread_create().
303 	 */
304 	THREAD_ONPROC(tp, cp);
305 	tp->t_preempt = 1;
306 	tp->t_bound_cpu = cp;
307 	tp->t_affinitycnt = 1;
308 	tp->t_cpu = cp;
309 	tp->t_disp_queue = cp->cpu_disp;
310 
311 	/*
312 	 * Setup thread to start in mp_startup_common.
313 	 */
314 	sp = tp->t_stk;
315 	tp->t_sp = (uintptr_t)(sp - MINFRAME);
316 #if defined(__amd64)
317 	tp->t_sp -= STACK_ENTRY_ALIGN;		/* fake a call */
318 #endif
319 	/*
320 	 * Setup thread start entry point for boot or hotplug.
321 	 */
322 	if (boot) {
323 		tp->t_pc = (uintptr_t)mp_startup_boot;
324 	} else {
325 		tp->t_pc = (uintptr_t)mp_startup_hotplug;
326 	}
327 
328 	cp->cpu_id = cpun;
329 	cp->cpu_self = cp;
330 	cp->cpu_thread = tp;
331 	cp->cpu_lwp = NULL;
332 	cp->cpu_dispthread = tp;
333 	cp->cpu_dispatch_pri = DISP_PRIO(tp);
334 
335 	/*
336 	 * cpu_base_spl must be set explicitly here to prevent any blocking
337 	 * operations in mp_startup_common from causing the spl of the cpu
338 	 * to drop to 0 (allowing device interrupts before we're ready) in
339 	 * resume().
340 	 * cpu_base_spl MUST remain at LOCK_LEVEL until the cpu is CPU_READY.
341 	 * As an extra bit of security on DEBUG kernels, this is enforced with
342 	 * an assertion in mp_startup_common() -- before cpu_base_spl is set
343 	 * to its proper value.
344 	 */
345 	cp->cpu_base_spl = ipltospl(LOCK_LEVEL);
346 
347 	/*
348 	 * Now, initialize per-CPU idle thread for this CPU.
349 	 */
350 	tp = thread_create(NULL, PAGESIZE, idle, NULL, 0, procp, TS_ONPROC, -1);
351 
352 	cp->cpu_idle_thread = tp;
353 
354 	tp->t_preempt = 1;
355 	tp->t_bound_cpu = cp;
356 	tp->t_affinitycnt = 1;
357 	tp->t_cpu = cp;
358 	tp->t_disp_queue = cp->cpu_disp;
359 
360 	/*
361 	 * Bootstrap the CPU's PG data
362 	 */
363 	pg_cpu_bootstrap(cp);
364 
365 	/*
366 	 * Perform CPC initialization on the new CPU.
367 	 */
368 	kcpc_hw_init(cp);
369 
370 	/*
371 	 * Allocate virtual addresses for cpu_caddr1 and cpu_caddr2
372 	 * for each CPU.
373 	 */
374 	setup_vaddr_for_ppcopy(cp);
375 
376 	/*
377 	 * Allocate page for new GDT and initialize from current GDT.
378 	 */
379 #if !defined(__lint)
380 	ASSERT((sizeof (*cp->cpu_gdt) * NGDT) <= PAGESIZE);
381 #endif
382 	cp->cpu_gdt = kmem_zalloc(PAGESIZE, KM_SLEEP);
383 	bcopy(CPU->cpu_gdt, cp->cpu_gdt, (sizeof (*cp->cpu_gdt) * NGDT));
384 
385 #if defined(__i386)
386 	/*
387 	 * setup kernel %gs.
388 	 */
389 	set_usegd(&cp->cpu_gdt[GDT_GS], cp, sizeof (struct cpu) -1, SDT_MEMRWA,
390 	    SEL_KPL, 0, 1);
391 #endif
392 
393 	/*
394 	 * If we have more than one node, each cpu gets a copy of IDT
395 	 * local to its node. If this is a Pentium box, we use cpu 0's
396 	 * IDT. cpu 0's IDT has been made read-only to workaround the
397 	 * cmpxchgl register bug
398 	 */
399 	if (system_hardware.hd_nodes && x86_type != X86_TYPE_P5) {
400 #if !defined(__lint)
401 		ASSERT((sizeof (*CPU->cpu_idt) * NIDT) <= PAGESIZE);
402 #endif
403 		cp->cpu_idt = kmem_zalloc(PAGESIZE, KM_SLEEP);
404 		bcopy(CPU->cpu_idt, cp->cpu_idt, PAGESIZE);
405 	} else {
406 		cp->cpu_idt = CPU->cpu_idt;
407 	}
408 
409 	/*
410 	 * Get interrupt priority data from cpu 0.
411 	 */
412 	cp->cpu_pri_data = CPU->cpu_pri_data;
413 
414 	/*
415 	 * alloc space for cpuid info
416 	 */
417 	cpuid_alloc_space(cp);
418 #if !defined(__xpv)
419 	if (is_x86_feature(x86_featureset, X86FSET_MWAIT) &&
420 	    idle_cpu_prefer_mwait) {
421 		cp->cpu_m.mcpu_mwait = cpuid_mwait_alloc(cp);
422 		cp->cpu_m.mcpu_idle_cpu = cpu_idle_mwait;
423 	} else
424 #endif
425 		cp->cpu_m.mcpu_idle_cpu = cpu_idle;
426 
427 	init_cpu_info(cp);
428 
429 	/*
430 	 * alloc space for ucode_info
431 	 */
432 	ucode_alloc_space(cp);
433 	xc_init_cpu(cp);
434 	hat_cpu_online(cp);
435 
436 #ifdef TRAPTRACE
437 	/*
438 	 * If this is a TRAPTRACE kernel, allocate TRAPTRACE buffers
439 	 */
440 	ttc->ttc_first = (uintptr_t)kmem_zalloc(trap_trace_bufsize, KM_SLEEP);
441 	ttc->ttc_next = ttc->ttc_first;
442 	ttc->ttc_limit = ttc->ttc_first + trap_trace_bufsize;
443 #endif
444 
445 	/*
446 	 * Record that we have another CPU.
447 	 */
448 	/*
449 	 * Initialize the interrupt threads for this CPU
450 	 */
451 	cpu_intr_alloc(cp, NINTR_THREADS);
452 
453 	cp->cpu_flags = CPU_OFFLINE | CPU_QUIESCED | CPU_POWEROFF;
454 	cpu_set_state(cp);
455 
456 	/*
457 	 * Add CPU to list of available CPUs.  It'll be on the active list
458 	 * after mp_startup_common().
459 	 */
460 	cpu_add_unit(cp);
461 
462 	return (cp);
463 }
464 
465 /*
466  * Undo what was done in mp_cpu_configure_common
467  */
468 static void
469 mp_cpu_unconfigure_common(struct cpu *cp, int error)
470 {
471 	ASSERT(MUTEX_HELD(&cpu_lock));
472 
473 	/*
474 	 * Remove the CPU from the list of available CPUs.
475 	 */
476 	cpu_del_unit(cp->cpu_id);
477 
478 	if (error == ETIMEDOUT) {
479 		/*
480 		 * The cpu was started, but never *seemed* to run any
481 		 * code in the kernel; it's probably off spinning in its
482 		 * own private world, though with potential references to
483 		 * our kmem-allocated IDTs and GDTs (for example).
484 		 *
485 		 * Worse still, it may actually wake up some time later,
486 		 * so rather than guess what it might or might not do, we
487 		 * leave the fundamental data structures intact.
488 		 */
489 		cp->cpu_flags = 0;
490 		return;
491 	}
492 
493 	/*
494 	 * At this point, the only threads bound to this CPU should
495 	 * special per-cpu threads: it's idle thread, it's pause threads,
496 	 * and it's interrupt threads.  Clean these up.
497 	 */
498 	cpu_destroy_bound_threads(cp);
499 	cp->cpu_idle_thread = NULL;
500 
501 	/*
502 	 * Free the interrupt stack.
503 	 */
504 	segkp_release(segkp,
505 	    cp->cpu_intr_stack - (INTR_STACK_SIZE - SA(MINFRAME)));
506 	cp->cpu_intr_stack = NULL;
507 
508 #ifdef TRAPTRACE
509 	/*
510 	 * Discard the trap trace buffer
511 	 */
512 	{
513 		trap_trace_ctl_t *ttc = &trap_trace_ctl[cp->cpu_id];
514 
515 		kmem_free((void *)ttc->ttc_first, trap_trace_bufsize);
516 		ttc->ttc_first = NULL;
517 	}
518 #endif
519 
520 	hat_cpu_offline(cp);
521 
522 	ucode_free_space(cp);
523 
524 	/* Free CPU ID string and brand string. */
525 	if (cp->cpu_idstr) {
526 		kmem_free(cp->cpu_idstr, CPU_IDSTRLEN);
527 		cp->cpu_idstr = NULL;
528 	}
529 	if (cp->cpu_brandstr) {
530 		kmem_free(cp->cpu_brandstr, CPU_IDSTRLEN);
531 		cp->cpu_brandstr = NULL;
532 	}
533 
534 #if !defined(__xpv)
535 	if (cp->cpu_m.mcpu_mwait != NULL) {
536 		cpuid_mwait_free(cp);
537 		cp->cpu_m.mcpu_mwait = NULL;
538 	}
539 #endif
540 	cpuid_free_space(cp);
541 
542 	if (cp->cpu_idt != CPU->cpu_idt)
543 		kmem_free(cp->cpu_idt, PAGESIZE);
544 	cp->cpu_idt = NULL;
545 
546 	kmem_free(cp->cpu_gdt, PAGESIZE);
547 	cp->cpu_gdt = NULL;
548 
549 	if (cp->cpu_supp_freqs != NULL) {
550 		size_t len = strlen(cp->cpu_supp_freqs) + 1;
551 		kmem_free(cp->cpu_supp_freqs, len);
552 		cp->cpu_supp_freqs = NULL;
553 	}
554 
555 	teardown_vaddr_for_ppcopy(cp);
556 
557 	kcpc_hw_fini(cp);
558 
559 	cp->cpu_dispthread = NULL;
560 	cp->cpu_thread = NULL;	/* discarded by cpu_destroy_bound_threads() */
561 
562 	cpu_vm_data_destroy(cp);
563 
564 	xc_fini_cpu(cp);
565 	disp_cpu_fini(cp);
566 
567 	ASSERT(cp != CPU0);
568 	bzero(cp, sizeof (*cp));
569 	cp->cpu_next_free = cpu_free_list;
570 	cpu_free_list = cp;
571 }
572 
573 /*
574  * Apply workarounds for known errata, and warn about those that are absent.
575  *
576  * System vendors occasionally create configurations which contain different
577  * revisions of the CPUs that are almost but not exactly the same.  At the
578  * time of writing, this meant that their clock rates were the same, their
579  * feature sets were the same, but the required workaround were -not-
580  * necessarily the same.  So, this routine is invoked on -every- CPU soon
581  * after starting to make sure that the resulting system contains the most
582  * pessimal set of workarounds needed to cope with *any* of the CPUs in the
583  * system.
584  *
585  * workaround_errata is invoked early in mlsetup() for CPU 0, and in
586  * mp_startup_common() for all slave CPUs. Slaves process workaround_errata
587  * prior to acknowledging their readiness to the master, so this routine will
588  * never be executed by multiple CPUs in parallel, thus making updates to
589  * global data safe.
590  *
591  * These workarounds are based on Rev 3.57 of the Revision Guide for
592  * AMD Athlon(tm) 64 and AMD Opteron(tm) Processors, August 2005.
593  */
594 
595 #if defined(OPTERON_ERRATUM_88)
596 int opteron_erratum_88;		/* if non-zero -> at least one cpu has it */
597 #endif
598 
599 #if defined(OPTERON_ERRATUM_91)
600 int opteron_erratum_91;		/* if non-zero -> at least one cpu has it */
601 #endif
602 
603 #if defined(OPTERON_ERRATUM_93)
604 int opteron_erratum_93;		/* if non-zero -> at least one cpu has it */
605 #endif
606 
607 #if defined(OPTERON_ERRATUM_95)
608 int opteron_erratum_95;		/* if non-zero -> at least one cpu has it */
609 #endif
610 
611 #if defined(OPTERON_ERRATUM_100)
612 int opteron_erratum_100;	/* if non-zero -> at least one cpu has it */
613 #endif
614 
615 #if defined(OPTERON_ERRATUM_108)
616 int opteron_erratum_108;	/* if non-zero -> at least one cpu has it */
617 #endif
618 
619 #if defined(OPTERON_ERRATUM_109)
620 int opteron_erratum_109;	/* if non-zero -> at least one cpu has it */
621 #endif
622 
623 #if defined(OPTERON_ERRATUM_121)
624 int opteron_erratum_121;	/* if non-zero -> at least one cpu has it */
625 #endif
626 
627 #if defined(OPTERON_ERRATUM_122)
628 int opteron_erratum_122;	/* if non-zero -> at least one cpu has it */
629 #endif
630 
631 #if defined(OPTERON_ERRATUM_123)
632 int opteron_erratum_123;	/* if non-zero -> at least one cpu has it */
633 #endif
634 
635 #if defined(OPTERON_ERRATUM_131)
636 int opteron_erratum_131;	/* if non-zero -> at least one cpu has it */
637 #endif
638 
639 #if defined(OPTERON_WORKAROUND_6336786)
640 int opteron_workaround_6336786;	/* non-zero -> WA relevant and applied */
641 int opteron_workaround_6336786_UP = 0;	/* Not needed for UP */
642 #endif
643 
644 #if defined(OPTERON_WORKAROUND_6323525)
645 int opteron_workaround_6323525;	/* if non-zero -> at least one cpu has it */
646 #endif
647 
648 #if defined(OPTERON_ERRATUM_298)
649 int opteron_erratum_298;
650 #endif
651 
652 static void
653 workaround_warning(cpu_t *cp, uint_t erratum)
654 {
655 	cmn_err(CE_WARN, "cpu%d: no workaround for erratum %u",
656 	    cp->cpu_id, erratum);
657 }
658 
659 static void
660 workaround_applied(uint_t erratum)
661 {
662 	if (erratum > 1000000)
663 		cmn_err(CE_CONT, "?workaround applied for cpu issue #%d\n",
664 		    erratum);
665 	else
666 		cmn_err(CE_CONT, "?workaround applied for cpu erratum #%d\n",
667 		    erratum);
668 }
669 
670 static void
671 msr_warning(cpu_t *cp, const char *rw, uint_t msr, int error)
672 {
673 	cmn_err(CE_WARN, "cpu%d: couldn't %smsr 0x%x, error %d",
674 	    cp->cpu_id, rw, msr, error);
675 }
676 
677 /*
678  * Determine the number of nodes in a Hammer / Greyhound / Griffin family
679  * system.
680  */
681 static uint_t
682 opteron_get_nnodes(void)
683 {
684 	static uint_t nnodes = 0;
685 
686 	if (nnodes == 0) {
687 #ifdef	DEBUG
688 		uint_t family;
689 
690 		/*
691 		 * This routine uses a PCI config space based mechanism
692 		 * for retrieving the number of nodes in the system.
693 		 * Device 24, function 0, offset 0x60 as used here is not
694 		 * AMD processor architectural, and may not work on processor
695 		 * families other than those listed below.
696 		 *
697 		 * Callers of this routine must ensure that we're running on
698 		 * a processor which supports this mechanism.
699 		 * The assertion below is meant to catch calls on unsupported
700 		 * processors.
701 		 */
702 		family = cpuid_getfamily(CPU);
703 		ASSERT(family == 0xf || family == 0x10 || family == 0x11);
704 #endif	/* DEBUG */
705 
706 		/*
707 		 * Obtain the number of nodes in the system from
708 		 * bits [6:4] of the Node ID register on node 0.
709 		 *
710 		 * The actual node count is NodeID[6:4] + 1
711 		 *
712 		 * The Node ID register is accessed via function 0,
713 		 * offset 0x60. Node 0 is device 24.
714 		 */
715 		nnodes = ((pci_getl_func(0, 24, 0, 0x60) & 0x70) >> 4) + 1;
716 	}
717 	return (nnodes);
718 }
719 
720 uint_t
721 do_erratum_298(struct cpu *cpu)
722 {
723 	static int	osvwrc = -3;
724 	extern int	osvw_opteron_erratum(cpu_t *, uint_t);
725 
726 	/*
727 	 * L2 Eviction May Occur During Processor Operation To Set
728 	 * Accessed or Dirty Bit.
729 	 */
730 	if (osvwrc == -3) {
731 		osvwrc = osvw_opteron_erratum(cpu, 298);
732 	} else {
733 		/* osvw return codes should be consistent for all cpus */
734 		ASSERT(osvwrc == osvw_opteron_erratum(cpu, 298));
735 	}
736 
737 	switch (osvwrc) {
738 	case 0:		/* erratum is not present: do nothing */
739 		break;
740 	case 1:		/* erratum is present: BIOS workaround applied */
741 		/*
742 		 * check if workaround is actually in place and issue warning
743 		 * if not.
744 		 */
745 		if (((rdmsr(MSR_AMD_HWCR) & AMD_HWCR_TLBCACHEDIS) == 0) ||
746 		    ((rdmsr(MSR_AMD_BU_CFG) & AMD_BU_CFG_E298) == 0)) {
747 #if defined(OPTERON_ERRATUM_298)
748 			opteron_erratum_298++;
749 #else
750 			workaround_warning(cpu, 298);
751 			return (1);
752 #endif
753 		}
754 		break;
755 	case -1:	/* cannot determine via osvw: check cpuid */
756 		if ((cpuid_opteron_erratum(cpu, 298) > 0) &&
757 		    (((rdmsr(MSR_AMD_HWCR) & AMD_HWCR_TLBCACHEDIS) == 0) ||
758 		    ((rdmsr(MSR_AMD_BU_CFG) & AMD_BU_CFG_E298) == 0))) {
759 #if defined(OPTERON_ERRATUM_298)
760 			opteron_erratum_298++;
761 #else
762 			workaround_warning(cpu, 298);
763 			return (1);
764 #endif
765 		}
766 		break;
767 	}
768 	return (0);
769 }
770 
771 uint_t
772 workaround_errata(struct cpu *cpu)
773 {
774 	uint_t missing = 0;
775 
776 	ASSERT(cpu == CPU);
777 
778 	/*LINTED*/
779 	if (cpuid_opteron_erratum(cpu, 88) > 0) {
780 		/*
781 		 * SWAPGS May Fail To Read Correct GS Base
782 		 */
783 #if defined(OPTERON_ERRATUM_88)
784 		/*
785 		 * The workaround is an mfence in the relevant assembler code
786 		 */
787 		opteron_erratum_88++;
788 #else
789 		workaround_warning(cpu, 88);
790 		missing++;
791 #endif
792 	}
793 
794 	if (cpuid_opteron_erratum(cpu, 91) > 0) {
795 		/*
796 		 * Software Prefetches May Report A Page Fault
797 		 */
798 #if defined(OPTERON_ERRATUM_91)
799 		/*
800 		 * fix is in trap.c
801 		 */
802 		opteron_erratum_91++;
803 #else
804 		workaround_warning(cpu, 91);
805 		missing++;
806 #endif
807 	}
808 
809 	if (cpuid_opteron_erratum(cpu, 93) > 0) {
810 		/*
811 		 * RSM Auto-Halt Restart Returns to Incorrect RIP
812 		 */
813 #if defined(OPTERON_ERRATUM_93)
814 		/*
815 		 * fix is in trap.c
816 		 */
817 		opteron_erratum_93++;
818 #else
819 		workaround_warning(cpu, 93);
820 		missing++;
821 #endif
822 	}
823 
824 	/*LINTED*/
825 	if (cpuid_opteron_erratum(cpu, 95) > 0) {
826 		/*
827 		 * RET Instruction May Return to Incorrect EIP
828 		 */
829 #if defined(OPTERON_ERRATUM_95)
830 #if defined(_LP64)
831 		/*
832 		 * Workaround this by ensuring that 32-bit user code and
833 		 * 64-bit kernel code never occupy the same address
834 		 * range mod 4G.
835 		 */
836 		if (_userlimit32 > 0xc0000000ul)
837 			*(uintptr_t *)&_userlimit32 = 0xc0000000ul;
838 
839 		/*LINTED*/
840 		ASSERT((uint32_t)COREHEAP_BASE == 0xc0000000u);
841 		opteron_erratum_95++;
842 #endif	/* _LP64 */
843 #else
844 		workaround_warning(cpu, 95);
845 		missing++;
846 #endif
847 	}
848 
849 	if (cpuid_opteron_erratum(cpu, 100) > 0) {
850 		/*
851 		 * Compatibility Mode Branches Transfer to Illegal Address
852 		 */
853 #if defined(OPTERON_ERRATUM_100)
854 		/*
855 		 * fix is in trap.c
856 		 */
857 		opteron_erratum_100++;
858 #else
859 		workaround_warning(cpu, 100);
860 		missing++;
861 #endif
862 	}
863 
864 	/*LINTED*/
865 	if (cpuid_opteron_erratum(cpu, 108) > 0) {
866 		/*
867 		 * CPUID Instruction May Return Incorrect Model Number In
868 		 * Some Processors
869 		 */
870 #if defined(OPTERON_ERRATUM_108)
871 		/*
872 		 * (Our cpuid-handling code corrects the model number on
873 		 * those processors)
874 		 */
875 #else
876 		workaround_warning(cpu, 108);
877 		missing++;
878 #endif
879 	}
880 
881 	/*LINTED*/
882 	if (cpuid_opteron_erratum(cpu, 109) > 0) do {
883 		/*
884 		 * Certain Reverse REP MOVS May Produce Unpredictable Behavior
885 		 */
886 #if defined(OPTERON_ERRATUM_109)
887 		/*
888 		 * The "workaround" is to print a warning to upgrade the BIOS
889 		 */
890 		uint64_t value;
891 		const uint_t msr = MSR_AMD_PATCHLEVEL;
892 		int err;
893 
894 		if ((err = checked_rdmsr(msr, &value)) != 0) {
895 			msr_warning(cpu, "rd", msr, err);
896 			workaround_warning(cpu, 109);
897 			missing++;
898 		}
899 		if (value == 0)
900 			opteron_erratum_109++;
901 #else
902 		workaround_warning(cpu, 109);
903 		missing++;
904 #endif
905 	/*CONSTANTCONDITION*/
906 	} while (0);
907 
908 	/*LINTED*/
909 	if (cpuid_opteron_erratum(cpu, 121) > 0) {
910 		/*
911 		 * Sequential Execution Across Non_Canonical Boundary Caused
912 		 * Processor Hang
913 		 */
914 #if defined(OPTERON_ERRATUM_121)
915 #if defined(_LP64)
916 		/*
917 		 * Erratum 121 is only present in long (64 bit) mode.
918 		 * Workaround is to include the page immediately before the
919 		 * va hole to eliminate the possibility of system hangs due to
920 		 * sequential execution across the va hole boundary.
921 		 */
922 		if (opteron_erratum_121)
923 			opteron_erratum_121++;
924 		else {
925 			if (hole_start) {
926 				hole_start -= PAGESIZE;
927 			} else {
928 				/*
929 				 * hole_start not yet initialized by
930 				 * mmu_init. Initialize hole_start
931 				 * with value to be subtracted.
932 				 */
933 				hole_start = PAGESIZE;
934 			}
935 			opteron_erratum_121++;
936 		}
937 #endif	/* _LP64 */
938 #else
939 		workaround_warning(cpu, 121);
940 		missing++;
941 #endif
942 	}
943 
944 	/*LINTED*/
945 	if (cpuid_opteron_erratum(cpu, 122) > 0) do {
946 		/*
947 		 * TLB Flush Filter May Cause Coherency Problem in
948 		 * Multiprocessor Systems
949 		 */
950 #if defined(OPTERON_ERRATUM_122)
951 		uint64_t value;
952 		const uint_t msr = MSR_AMD_HWCR;
953 		int error;
954 
955 		/*
956 		 * Erratum 122 is only present in MP configurations (multi-core
957 		 * or multi-processor).
958 		 */
959 #if defined(__xpv)
960 		if (!DOMAIN_IS_INITDOMAIN(xen_info))
961 			break;
962 		if (!opteron_erratum_122 && xpv_nr_phys_cpus() == 1)
963 			break;
964 #else
965 		if (!opteron_erratum_122 && opteron_get_nnodes() == 1 &&
966 		    cpuid_get_ncpu_per_chip(cpu) == 1)
967 			break;
968 #endif
969 		/* disable TLB Flush Filter */
970 
971 		if ((error = checked_rdmsr(msr, &value)) != 0) {
972 			msr_warning(cpu, "rd", msr, error);
973 			workaround_warning(cpu, 122);
974 			missing++;
975 		} else {
976 			value |= (uint64_t)AMD_HWCR_FFDIS;
977 			if ((error = checked_wrmsr(msr, value)) != 0) {
978 				msr_warning(cpu, "wr", msr, error);
979 				workaround_warning(cpu, 122);
980 				missing++;
981 			}
982 		}
983 		opteron_erratum_122++;
984 #else
985 		workaround_warning(cpu, 122);
986 		missing++;
987 #endif
988 	/*CONSTANTCONDITION*/
989 	} while (0);
990 
991 	/*LINTED*/
992 	if (cpuid_opteron_erratum(cpu, 123) > 0) do {
993 		/*
994 		 * Bypassed Reads May Cause Data Corruption of System Hang in
995 		 * Dual Core Processors
996 		 */
997 #if defined(OPTERON_ERRATUM_123)
998 		uint64_t value;
999 		const uint_t msr = MSR_AMD_PATCHLEVEL;
1000 		int err;
1001 
1002 		/*
1003 		 * Erratum 123 applies only to multi-core cpus.
1004 		 */
1005 		if (cpuid_get_ncpu_per_chip(cpu) < 2)
1006 			break;
1007 #if defined(__xpv)
1008 		if (!DOMAIN_IS_INITDOMAIN(xen_info))
1009 			break;
1010 #endif
1011 		/*
1012 		 * The "workaround" is to print a warning to upgrade the BIOS
1013 		 */
1014 		if ((err = checked_rdmsr(msr, &value)) != 0) {
1015 			msr_warning(cpu, "rd", msr, err);
1016 			workaround_warning(cpu, 123);
1017 			missing++;
1018 		}
1019 		if (value == 0)
1020 			opteron_erratum_123++;
1021 #else
1022 		workaround_warning(cpu, 123);
1023 		missing++;
1024 
1025 #endif
1026 	/*CONSTANTCONDITION*/
1027 	} while (0);
1028 
1029 	/*LINTED*/
1030 	if (cpuid_opteron_erratum(cpu, 131) > 0) do {
1031 		/*
1032 		 * Multiprocessor Systems with Four or More Cores May Deadlock
1033 		 * Waiting for a Probe Response
1034 		 */
1035 #if defined(OPTERON_ERRATUM_131)
1036 		uint64_t nbcfg;
1037 		const uint_t msr = MSR_AMD_NB_CFG;
1038 		const uint64_t wabits =
1039 		    AMD_NB_CFG_SRQ_HEARTBEAT | AMD_NB_CFG_SRQ_SPR;
1040 		int error;
1041 
1042 		/*
1043 		 * Erratum 131 applies to any system with four or more cores.
1044 		 */
1045 		if (opteron_erratum_131)
1046 			break;
1047 #if defined(__xpv)
1048 		if (!DOMAIN_IS_INITDOMAIN(xen_info))
1049 			break;
1050 		if (xpv_nr_phys_cpus() < 4)
1051 			break;
1052 #else
1053 		if (opteron_get_nnodes() * cpuid_get_ncpu_per_chip(cpu) < 4)
1054 			break;
1055 #endif
1056 		/*
1057 		 * Print a warning if neither of the workarounds for
1058 		 * erratum 131 is present.
1059 		 */
1060 		if ((error = checked_rdmsr(msr, &nbcfg)) != 0) {
1061 			msr_warning(cpu, "rd", msr, error);
1062 			workaround_warning(cpu, 131);
1063 			missing++;
1064 		} else if ((nbcfg & wabits) == 0) {
1065 			opteron_erratum_131++;
1066 		} else {
1067 			/* cannot have both workarounds set */
1068 			ASSERT((nbcfg & wabits) != wabits);
1069 		}
1070 #else
1071 		workaround_warning(cpu, 131);
1072 		missing++;
1073 #endif
1074 	/*CONSTANTCONDITION*/
1075 	} while (0);
1076 
1077 	/*
1078 	 * This isn't really an erratum, but for convenience the
1079 	 * detection/workaround code lives here and in cpuid_opteron_erratum.
1080 	 */
1081 	if (cpuid_opteron_erratum(cpu, 6336786) > 0) {
1082 #if defined(OPTERON_WORKAROUND_6336786)
1083 		/*
1084 		 * Disable C1-Clock ramping on multi-core/multi-processor
1085 		 * K8 platforms to guard against TSC drift.
1086 		 */
1087 		if (opteron_workaround_6336786) {
1088 			opteron_workaround_6336786++;
1089 #if defined(__xpv)
1090 		} else if ((DOMAIN_IS_INITDOMAIN(xen_info) &&
1091 		    xpv_nr_phys_cpus() > 1) ||
1092 		    opteron_workaround_6336786_UP) {
1093 			/*
1094 			 * XXPV	Hmm.  We can't walk the Northbridges on
1095 			 *	the hypervisor; so just complain and drive
1096 			 *	on.  This probably needs to be fixed in
1097 			 *	the hypervisor itself.
1098 			 */
1099 			opteron_workaround_6336786++;
1100 			workaround_warning(cpu, 6336786);
1101 #else	/* __xpv */
1102 		} else if ((opteron_get_nnodes() *
1103 		    cpuid_get_ncpu_per_chip(cpu) > 1) ||
1104 		    opteron_workaround_6336786_UP) {
1105 
1106 			uint_t	node, nnodes;
1107 			uint8_t data;
1108 
1109 			nnodes = opteron_get_nnodes();
1110 			for (node = 0; node < nnodes; node++) {
1111 				/*
1112 				 * Clear PMM7[1:0] (function 3, offset 0x87)
1113 				 * Northbridge device is the node id + 24.
1114 				 */
1115 				data = pci_getb_func(0, node + 24, 3, 0x87);
1116 				data &= 0xFC;
1117 				pci_putb_func(0, node + 24, 3, 0x87, data);
1118 			}
1119 			opteron_workaround_6336786++;
1120 #endif	/* __xpv */
1121 		}
1122 #else
1123 		workaround_warning(cpu, 6336786);
1124 		missing++;
1125 #endif
1126 	}
1127 
1128 	/*LINTED*/
1129 	/*
1130 	 * Mutex primitives don't work as expected.
1131 	 */
1132 	if (cpuid_opteron_erratum(cpu, 6323525) > 0) {
1133 #if defined(OPTERON_WORKAROUND_6323525)
1134 		/*
1135 		 * This problem only occurs with 2 or more cores. If bit in
1136 		 * MSR_AMD_BU_CFG set, then not applicable. The workaround
1137 		 * is to patch the semaphone routines with the lfence
1138 		 * instruction to provide necessary load memory barrier with
1139 		 * possible subsequent read-modify-write ops.
1140 		 *
1141 		 * It is too early in boot to call the patch routine so
1142 		 * set erratum variable to be done in startup_end().
1143 		 */
1144 		if (opteron_workaround_6323525) {
1145 			opteron_workaround_6323525++;
1146 #if defined(__xpv)
1147 		} else if (is_x86_feature(x86_featureset, X86FSET_SSE2)) {
1148 			if (DOMAIN_IS_INITDOMAIN(xen_info)) {
1149 				/*
1150 				 * XXPV	Use dom0_msr here when extended
1151 				 *	operations are supported?
1152 				 */
1153 				if (xpv_nr_phys_cpus() > 1)
1154 					opteron_workaround_6323525++;
1155 			} else {
1156 				/*
1157 				 * We have no way to tell how many physical
1158 				 * cpus there are, or even if this processor
1159 				 * has the problem, so enable the workaround
1160 				 * unconditionally (at some performance cost).
1161 				 */
1162 				opteron_workaround_6323525++;
1163 			}
1164 #else	/* __xpv */
1165 		} else if (is_x86_feature(x86_featureset, X86FSET_SSE2) &&
1166 		    ((opteron_get_nnodes() *
1167 		    cpuid_get_ncpu_per_chip(cpu)) > 1)) {
1168 			if ((xrdmsr(MSR_AMD_BU_CFG) & (UINT64_C(1) << 33)) == 0)
1169 				opteron_workaround_6323525++;
1170 #endif	/* __xpv */
1171 		}
1172 #else
1173 		workaround_warning(cpu, 6323525);
1174 		missing++;
1175 #endif
1176 	}
1177 
1178 	missing += do_erratum_298(cpu);
1179 
1180 #ifdef __xpv
1181 	return (0);
1182 #else
1183 	return (missing);
1184 #endif
1185 }
1186 
1187 void
1188 workaround_errata_end()
1189 {
1190 #if defined(OPTERON_ERRATUM_88)
1191 	if (opteron_erratum_88)
1192 		workaround_applied(88);
1193 #endif
1194 #if defined(OPTERON_ERRATUM_91)
1195 	if (opteron_erratum_91)
1196 		workaround_applied(91);
1197 #endif
1198 #if defined(OPTERON_ERRATUM_93)
1199 	if (opteron_erratum_93)
1200 		workaround_applied(93);
1201 #endif
1202 #if defined(OPTERON_ERRATUM_95)
1203 	if (opteron_erratum_95)
1204 		workaround_applied(95);
1205 #endif
1206 #if defined(OPTERON_ERRATUM_100)
1207 	if (opteron_erratum_100)
1208 		workaround_applied(100);
1209 #endif
1210 #if defined(OPTERON_ERRATUM_108)
1211 	if (opteron_erratum_108)
1212 		workaround_applied(108);
1213 #endif
1214 #if defined(OPTERON_ERRATUM_109)
1215 	if (opteron_erratum_109) {
1216 		cmn_err(CE_WARN,
1217 		    "BIOS microcode patch for AMD Athlon(tm) 64/Opteron(tm)"
1218 		    " processor\nerratum 109 was not detected; updating your"
1219 		    " system's BIOS to a version\ncontaining this"
1220 		    " microcode patch is HIGHLY recommended or erroneous"
1221 		    " system\noperation may occur.\n");
1222 	}
1223 #endif
1224 #if defined(OPTERON_ERRATUM_121)
1225 	if (opteron_erratum_121)
1226 		workaround_applied(121);
1227 #endif
1228 #if defined(OPTERON_ERRATUM_122)
1229 	if (opteron_erratum_122)
1230 		workaround_applied(122);
1231 #endif
1232 #if defined(OPTERON_ERRATUM_123)
1233 	if (opteron_erratum_123) {
1234 		cmn_err(CE_WARN,
1235 		    "BIOS microcode patch for AMD Athlon(tm) 64/Opteron(tm)"
1236 		    " processor\nerratum 123 was not detected; updating your"
1237 		    " system's BIOS to a version\ncontaining this"
1238 		    " microcode patch is HIGHLY recommended or erroneous"
1239 		    " system\noperation may occur.\n");
1240 	}
1241 #endif
1242 #if defined(OPTERON_ERRATUM_131)
1243 	if (opteron_erratum_131) {
1244 		cmn_err(CE_WARN,
1245 		    "BIOS microcode patch for AMD Athlon(tm) 64/Opteron(tm)"
1246 		    " processor\nerratum 131 was not detected; updating your"
1247 		    " system's BIOS to a version\ncontaining this"
1248 		    " microcode patch is HIGHLY recommended or erroneous"
1249 		    " system\noperation may occur.\n");
1250 	}
1251 #endif
1252 #if defined(OPTERON_WORKAROUND_6336786)
1253 	if (opteron_workaround_6336786)
1254 		workaround_applied(6336786);
1255 #endif
1256 #if defined(OPTERON_WORKAROUND_6323525)
1257 	if (opteron_workaround_6323525)
1258 		workaround_applied(6323525);
1259 #endif
1260 #if defined(OPTERON_ERRATUM_298)
1261 	if (opteron_erratum_298) {
1262 		cmn_err(CE_WARN,
1263 		    "BIOS microcode patch for AMD 64/Opteron(tm)"
1264 		    " processor\nerratum 298 was not detected; updating your"
1265 		    " system's BIOS to a version\ncontaining this"
1266 		    " microcode patch is HIGHLY recommended or erroneous"
1267 		    " system\noperation may occur.\n");
1268 	}
1269 #endif
1270 }
1271 
1272 /*
1273  * The procset_slave and procset_master are used to synchronize
1274  * between the control CPU and the target CPU when starting CPUs.
1275  */
1276 static cpuset_t procset_slave, procset_master;
1277 
1278 static void
1279 mp_startup_wait(cpuset_t *sp, processorid_t cpuid)
1280 {
1281 	cpuset_t tempset;
1282 
1283 	for (tempset = *sp; !CPU_IN_SET(tempset, cpuid);
1284 	    tempset = *(volatile cpuset_t *)sp) {
1285 		SMT_PAUSE();
1286 	}
1287 	CPUSET_ATOMIC_DEL(*(cpuset_t *)sp, cpuid);
1288 }
1289 
1290 static void
1291 mp_startup_signal(cpuset_t *sp, processorid_t cpuid)
1292 {
1293 	cpuset_t tempset;
1294 
1295 	CPUSET_ATOMIC_ADD(*(cpuset_t *)sp, cpuid);
1296 	for (tempset = *sp; CPU_IN_SET(tempset, cpuid);
1297 	    tempset = *(volatile cpuset_t *)sp) {
1298 		SMT_PAUSE();
1299 	}
1300 }
1301 
1302 int
1303 mp_start_cpu_common(cpu_t *cp, boolean_t boot)
1304 {
1305 	_NOTE(ARGUNUSED(boot));
1306 
1307 	void *ctx;
1308 	int delays;
1309 	int error = 0;
1310 	cpuset_t tempset;
1311 	processorid_t cpuid;
1312 #ifndef __xpv
1313 	extern void cpupm_init(cpu_t *);
1314 #endif
1315 
1316 	ASSERT(cp != NULL);
1317 	cpuid = cp->cpu_id;
1318 	ctx = mach_cpucontext_alloc(cp);
1319 	if (ctx == NULL) {
1320 		cmn_err(CE_WARN,
1321 		    "cpu%d: failed to allocate context", cp->cpu_id);
1322 		return (EAGAIN);
1323 	}
1324 	error = mach_cpu_start(cp, ctx);
1325 	if (error != 0) {
1326 		cmn_err(CE_WARN,
1327 		    "cpu%d: failed to start, error %d", cp->cpu_id, error);
1328 		mach_cpucontext_free(cp, ctx, error);
1329 		return (error);
1330 	}
1331 
1332 	for (delays = 0, tempset = procset_slave; !CPU_IN_SET(tempset, cpuid);
1333 	    delays++) {
1334 		if (delays == 500) {
1335 			/*
1336 			 * After five seconds, things are probably looking
1337 			 * a bit bleak - explain the hang.
1338 			 */
1339 			cmn_err(CE_NOTE, "cpu%d: started, "
1340 			    "but not running in the kernel yet", cpuid);
1341 		} else if (delays > 2000) {
1342 			/*
1343 			 * We waited at least 20 seconds, bail ..
1344 			 */
1345 			error = ETIMEDOUT;
1346 			cmn_err(CE_WARN, "cpu%d: timed out", cpuid);
1347 			mach_cpucontext_free(cp, ctx, error);
1348 			return (error);
1349 		}
1350 
1351 		/*
1352 		 * wait at least 10ms, then check again..
1353 		 */
1354 		delay(USEC_TO_TICK_ROUNDUP(10000));
1355 		tempset = *((volatile cpuset_t *)&procset_slave);
1356 	}
1357 	CPUSET_ATOMIC_DEL(procset_slave, cpuid);
1358 
1359 	mach_cpucontext_free(cp, ctx, 0);
1360 
1361 #ifndef __xpv
1362 	if (tsc_gethrtime_enable)
1363 		tsc_sync_master(cpuid);
1364 #endif
1365 
1366 	if (dtrace_cpu_init != NULL) {
1367 		(*dtrace_cpu_init)(cpuid);
1368 	}
1369 
1370 	/*
1371 	 * During CPU DR operations, the cpu_lock is held by current
1372 	 * (the control) thread. We can't release the cpu_lock here
1373 	 * because that will break the CPU DR logic.
1374 	 * On the other hand, CPUPM and processor group initialization
1375 	 * routines need to access the cpu_lock. So we invoke those
1376 	 * routines here on behalf of mp_startup_common().
1377 	 *
1378 	 * CPUPM and processor group initialization routines depend
1379 	 * on the cpuid probing results. Wait for mp_startup_common()
1380 	 * to signal that cpuid probing is done.
1381 	 */
1382 	mp_startup_wait(&procset_slave, cpuid);
1383 #ifndef __xpv
1384 	cpupm_init(cp);
1385 #endif
1386 	(void) pg_cpu_init(cp, B_FALSE);
1387 	cpu_set_state(cp);
1388 	mp_startup_signal(&procset_master, cpuid);
1389 
1390 	return (0);
1391 }
1392 
1393 /*
1394  * Start a single cpu, assuming that the kernel context is available
1395  * to successfully start another cpu.
1396  *
1397  * (For example, real mode code is mapped into the right place
1398  * in memory and is ready to be run.)
1399  */
1400 int
1401 start_cpu(processorid_t who)
1402 {
1403 	cpu_t *cp;
1404 	int error = 0;
1405 	cpuset_t tempset;
1406 
1407 	ASSERT(who != 0);
1408 
1409 	/*
1410 	 * Check if there's at least a Mbyte of kmem available
1411 	 * before attempting to start the cpu.
1412 	 */
1413 	if (kmem_avail() < 1024 * 1024) {
1414 		/*
1415 		 * Kick off a reap in case that helps us with
1416 		 * later attempts ..
1417 		 */
1418 		kmem_reap();
1419 		return (ENOMEM);
1420 	}
1421 
1422 	/*
1423 	 * First configure cpu.
1424 	 */
1425 	cp = mp_cpu_configure_common(who, B_TRUE);
1426 	ASSERT(cp != NULL);
1427 
1428 	/*
1429 	 * Then start cpu.
1430 	 */
1431 	error = mp_start_cpu_common(cp, B_TRUE);
1432 	if (error != 0) {
1433 		mp_cpu_unconfigure_common(cp, error);
1434 		return (error);
1435 	}
1436 
1437 	mutex_exit(&cpu_lock);
1438 	tempset = cpu_ready_set;
1439 	while (!CPU_IN_SET(tempset, who)) {
1440 		drv_usecwait(1);
1441 		tempset = *((volatile cpuset_t *)&cpu_ready_set);
1442 	}
1443 	mutex_enter(&cpu_lock);
1444 
1445 	return (0);
1446 }
1447 
1448 void
1449 start_other_cpus(int cprboot)
1450 {
1451 	_NOTE(ARGUNUSED(cprboot));
1452 
1453 	uint_t who;
1454 	uint_t bootcpuid = 0;
1455 
1456 	/*
1457 	 * Initialize our own cpu_info.
1458 	 */
1459 	init_cpu_info(CPU);
1460 
1461 	cmn_err(CE_CONT, "?cpu%d: %s\n", CPU->cpu_id, CPU->cpu_idstr);
1462 	cmn_err(CE_CONT, "?cpu%d: %s\n", CPU->cpu_id, CPU->cpu_brandstr);
1463 
1464 	/*
1465 	 * Initialize our syscall handlers
1466 	 */
1467 	init_cpu_syscall(CPU);
1468 
1469 	/*
1470 	 * Take the boot cpu out of the mp_cpus set because we know
1471 	 * it's already running.  Add it to the cpu_ready_set for
1472 	 * precisely the same reason.
1473 	 */
1474 	CPUSET_DEL(mp_cpus, bootcpuid);
1475 	CPUSET_ADD(cpu_ready_set, bootcpuid);
1476 
1477 	/*
1478 	 * skip the rest of this if
1479 	 * . only 1 cpu dectected and system isn't hotplug-capable
1480 	 * . not using MP
1481 	 */
1482 	if ((CPUSET_ISNULL(mp_cpus) && plat_dr_support_cpu() == 0) ||
1483 	    use_mp == 0) {
1484 		if (use_mp == 0)
1485 			cmn_err(CE_CONT, "?***** Not in MP mode\n");
1486 		goto done;
1487 	}
1488 
1489 	/*
1490 	 * perform such initialization as is needed
1491 	 * to be able to take CPUs on- and off-line.
1492 	 */
1493 	cpu_pause_init();
1494 
1495 	xc_init_cpu(CPU);		/* initialize processor crosscalls */
1496 
1497 	if (mach_cpucontext_init() != 0)
1498 		goto done;
1499 
1500 	flushes_require_xcalls = 1;
1501 
1502 	/*
1503 	 * We lock our affinity to the master CPU to ensure that all slave CPUs
1504 	 * do their TSC syncs with the same CPU.
1505 	 */
1506 	affinity_set(CPU_CURRENT);
1507 
1508 	for (who = 0; who < NCPU; who++) {
1509 		if (!CPU_IN_SET(mp_cpus, who))
1510 			continue;
1511 		ASSERT(who != bootcpuid);
1512 
1513 		mutex_enter(&cpu_lock);
1514 		if (start_cpu(who) != 0)
1515 			CPUSET_DEL(mp_cpus, who);
1516 		cpu_state_change_notify(who, CPU_SETUP);
1517 		mutex_exit(&cpu_lock);
1518 	}
1519 
1520 	/* Free the space allocated to hold the microcode file */
1521 	ucode_cleanup();
1522 
1523 	affinity_clear();
1524 
1525 	mach_cpucontext_fini();
1526 
1527 done:
1528 	if (get_hwenv() == HW_NATIVE)
1529 		workaround_errata_end();
1530 	cmi_post_mpstartup();
1531 
1532 	if (use_mp && ncpus != boot_max_ncpus) {
1533 		cmn_err(CE_NOTE,
1534 		    "System detected %d cpus, but "
1535 		    "only %d cpu(s) were enabled during boot.",
1536 		    boot_max_ncpus, ncpus);
1537 		cmn_err(CE_NOTE,
1538 		    "Use \"boot-ncpus\" parameter to enable more CPU(s). "
1539 		    "See eeprom(1M).");
1540 	}
1541 }
1542 
1543 int
1544 mp_cpu_configure(int cpuid)
1545 {
1546 	cpu_t *cp;
1547 
1548 	if (use_mp == 0 || plat_dr_support_cpu() == 0) {
1549 		return (ENOTSUP);
1550 	}
1551 
1552 	cp = cpu_get(cpuid);
1553 	if (cp != NULL) {
1554 		return (EALREADY);
1555 	}
1556 
1557 	/*
1558 	 * Check if there's at least a Mbyte of kmem available
1559 	 * before attempting to start the cpu.
1560 	 */
1561 	if (kmem_avail() < 1024 * 1024) {
1562 		/*
1563 		 * Kick off a reap in case that helps us with
1564 		 * later attempts ..
1565 		 */
1566 		kmem_reap();
1567 		return (ENOMEM);
1568 	}
1569 
1570 	cp = mp_cpu_configure_common(cpuid, B_FALSE);
1571 	ASSERT(cp != NULL && cpu_get(cpuid) == cp);
1572 
1573 	return (cp != NULL ? 0 : EAGAIN);
1574 }
1575 
1576 int
1577 mp_cpu_unconfigure(int cpuid)
1578 {
1579 	cpu_t *cp;
1580 
1581 	if (use_mp == 0 || plat_dr_support_cpu() == 0) {
1582 		return (ENOTSUP);
1583 	} else if (cpuid < 0 || cpuid >= max_ncpus) {
1584 		return (EINVAL);
1585 	}
1586 
1587 	cp = cpu_get(cpuid);
1588 	if (cp == NULL) {
1589 		return (ENODEV);
1590 	}
1591 	mp_cpu_unconfigure_common(cp, 0);
1592 
1593 	return (0);
1594 }
1595 
1596 /*
1597  * Startup function for 'other' CPUs (besides boot cpu).
1598  * Called from real_mode_start.
1599  *
1600  * WARNING: until CPU_READY is set, mp_startup_common and routines called by
1601  * mp_startup_common should not call routines (e.g. kmem_free) that could call
1602  * hat_unload which requires CPU_READY to be set.
1603  */
1604 static void
1605 mp_startup_common(boolean_t boot)
1606 {
1607 	cpu_t *cp = CPU;
1608 	void *new_x86_featureset;
1609 	extern void cpu_event_init_cpu(cpu_t *);
1610 
1611 	/*
1612 	 * We need to get TSC on this proc synced (i.e., any delta
1613 	 * from cpu0 accounted for) as soon as we can, because many
1614 	 * many things use gethrtime/pc_gethrestime, including
1615 	 * interrupts, cmn_err, etc.
1616 	 */
1617 
1618 	/* Let the control CPU continue into tsc_sync_master() */
1619 	mp_startup_signal(&procset_slave, cp->cpu_id);
1620 
1621 #ifndef __xpv
1622 	if (tsc_gethrtime_enable)
1623 		tsc_sync_slave();
1624 #endif
1625 
1626 	/*
1627 	 * Once this was done from assembly, but it's safer here; if
1628 	 * it blocks, we need to be able to swtch() to and from, and
1629 	 * since we get here by calling t_pc, we need to do that call
1630 	 * before swtch() overwrites it.
1631 	 */
1632 	(void) (*ap_mlsetup)();
1633 
1634 	new_x86_featureset = cpuid_pass1(cp);
1635 
1636 #ifndef __xpv
1637 	/*
1638 	 * Program this cpu's PAT
1639 	 */
1640 	if (is_x86_feature(x86_featureset, X86FSET_PAT))
1641 		pat_sync();
1642 #endif
1643 
1644 	/*
1645 	 * Set up TSC_AUX to contain the cpuid for this processor
1646 	 * for the rdtscp instruction.
1647 	 */
1648 	if (is_x86_feature(x86_featureset, X86FSET_TSCP))
1649 		(void) wrmsr(MSR_AMD_TSCAUX, cp->cpu_id);
1650 
1651 	/*
1652 	 * Initialize this CPU's syscall handlers
1653 	 */
1654 	init_cpu_syscall(cp);
1655 
1656 	/*
1657 	 * Enable interrupts with spl set to LOCK_LEVEL. LOCK_LEVEL is the
1658 	 * highest level at which a routine is permitted to block on
1659 	 * an adaptive mutex (allows for cpu poke interrupt in case
1660 	 * the cpu is blocked on a mutex and halts). Setting LOCK_LEVEL blocks
1661 	 * device interrupts that may end up in the hat layer issuing cross
1662 	 * calls before CPU_READY is set.
1663 	 */
1664 	splx(ipltospl(LOCK_LEVEL));
1665 	sti();
1666 
1667 	/*
1668 	 * Do a sanity check to make sure this new CPU is a sane thing
1669 	 * to add to the collection of processors running this system.
1670 	 *
1671 	 * XXX	Clearly this needs to get more sophisticated, if x86
1672 	 * systems start to get built out of heterogenous CPUs; as is
1673 	 * likely to happen once the number of processors in a configuration
1674 	 * gets large enough.
1675 	 */
1676 	if (compare_x86_featureset(x86_featureset, new_x86_featureset) ==
1677 	    B_FALSE) {
1678 		cmn_err(CE_CONT, "cpu%d: featureset\n", cp->cpu_id);
1679 		print_x86_featureset(new_x86_featureset);
1680 		cmn_err(CE_WARN, "cpu%d feature mismatch", cp->cpu_id);
1681 	}
1682 
1683 	/*
1684 	 * We do not support cpus with mixed monitor/mwait support if the
1685 	 * boot cpu supports monitor/mwait.
1686 	 */
1687 	if (is_x86_feature(x86_featureset, X86FSET_MWAIT) !=
1688 	    is_x86_feature(new_x86_featureset, X86FSET_MWAIT))
1689 		panic("unsupported mixed cpu monitor/mwait support detected");
1690 
1691 	free_x86_featureset(new_x86_featureset);
1692 
1693 	/*
1694 	 * We could be more sophisticated here, and just mark the CPU
1695 	 * as "faulted" but at this point we'll opt for the easier
1696 	 * answer of dying horribly.  Provided the boot cpu is ok,
1697 	 * the system can be recovered by booting with use_mp set to zero.
1698 	 */
1699 	if (workaround_errata(cp) != 0)
1700 		panic("critical workaround(s) missing for cpu%d", cp->cpu_id);
1701 
1702 	/*
1703 	 * We can touch cpu_flags here without acquiring the cpu_lock here
1704 	 * because the cpu_lock is held by the control CPU which is running
1705 	 * mp_start_cpu_common().
1706 	 * Need to clear CPU_QUIESCED flag before calling any function which
1707 	 * may cause thread context switching, such as kmem_alloc() etc.
1708 	 * The idle thread checks for CPU_QUIESCED flag and loops for ever if
1709 	 * it's set. So the startup thread may have no chance to switch back
1710 	 * again if it's switched away with CPU_QUIESCED set.
1711 	 */
1712 	cp->cpu_flags &= ~(CPU_POWEROFF | CPU_QUIESCED);
1713 
1714 	cpuid_pass2(cp);
1715 	cpuid_pass3(cp);
1716 	(void) cpuid_pass4(cp);
1717 
1718 	/*
1719 	 * Correct cpu_idstr and cpu_brandstr on target CPU after
1720 	 * cpuid_pass1() is done.
1721 	 */
1722 	(void) cpuid_getidstr(cp, cp->cpu_idstr, CPU_IDSTRLEN);
1723 	(void) cpuid_getbrandstr(cp, cp->cpu_brandstr, CPU_IDSTRLEN);
1724 
1725 	cp->cpu_flags |= CPU_RUNNING | CPU_READY | CPU_EXISTS;
1726 
1727 	post_startup_cpu_fixups();
1728 
1729 	cpu_event_init_cpu(cp);
1730 
1731 	/*
1732 	 * Enable preemption here so that contention for any locks acquired
1733 	 * later in mp_startup_common may be preempted if the thread owning
1734 	 * those locks is continuously executing on other CPUs (for example,
1735 	 * this CPU must be preemptible to allow other CPUs to pause it during
1736 	 * their startup phases).  It's safe to enable preemption here because
1737 	 * the CPU state is pretty-much fully constructed.
1738 	 */
1739 	curthread->t_preempt = 0;
1740 
1741 	/* The base spl should still be at LOCK LEVEL here */
1742 	ASSERT(cp->cpu_base_spl == ipltospl(LOCK_LEVEL));
1743 	set_base_spl();		/* Restore the spl to its proper value */
1744 
1745 	pghw_physid_create(cp);
1746 	/*
1747 	 * Delegate initialization tasks, which need to access the cpu_lock,
1748 	 * to mp_start_cpu_common() because we can't acquire the cpu_lock here
1749 	 * during CPU DR operations.
1750 	 */
1751 	mp_startup_signal(&procset_slave, cp->cpu_id);
1752 	mp_startup_wait(&procset_master, cp->cpu_id);
1753 	pg_cmt_cpu_startup(cp);
1754 
1755 	if (boot) {
1756 		mutex_enter(&cpu_lock);
1757 		cp->cpu_flags &= ~CPU_OFFLINE;
1758 		cpu_enable_intr(cp);
1759 		cpu_add_active(cp);
1760 		mutex_exit(&cpu_lock);
1761 	}
1762 
1763 	/* Enable interrupts */
1764 	(void) spl0();
1765 
1766 	/*
1767 	 * Fill out cpu_ucode_info.  Update microcode if necessary.
1768 	 */
1769 	ucode_check(cp);
1770 
1771 #ifndef __xpv
1772 	{
1773 		/*
1774 		 * Set up the CPU module for this CPU.  This can't be done
1775 		 * before this CPU is made CPU_READY, because we may (in
1776 		 * heterogeneous systems) need to go load another CPU module.
1777 		 * The act of attempting to load a module may trigger a
1778 		 * cross-call, which will ASSERT unless this cpu is CPU_READY.
1779 		 */
1780 		cmi_hdl_t hdl;
1781 
1782 		if ((hdl = cmi_init(CMI_HDL_NATIVE, cmi_ntv_hwchipid(CPU),
1783 		    cmi_ntv_hwcoreid(CPU), cmi_ntv_hwstrandid(CPU))) != NULL) {
1784 			if (is_x86_feature(x86_featureset, X86FSET_MCA))
1785 				cmi_mca_init(hdl);
1786 			cp->cpu_m.mcpu_cmi_hdl = hdl;
1787 		}
1788 	}
1789 #endif /* __xpv */
1790 
1791 	if (boothowto & RB_DEBUG)
1792 		kdi_cpu_init();
1793 
1794 	/*
1795 	 * Setting the bit in cpu_ready_set must be the last operation in
1796 	 * processor initialization; the boot CPU will continue to boot once
1797 	 * it sees this bit set for all active CPUs.
1798 	 */
1799 	CPUSET_ATOMIC_ADD(cpu_ready_set, cp->cpu_id);
1800 
1801 	(void) mach_cpu_create_device_node(cp, NULL);
1802 
1803 	cmn_err(CE_CONT, "?cpu%d: %s\n", cp->cpu_id, cp->cpu_idstr);
1804 	cmn_err(CE_CONT, "?cpu%d: %s\n", cp->cpu_id, cp->cpu_brandstr);
1805 	cmn_err(CE_CONT, "?cpu%d initialization complete - online\n",
1806 	    cp->cpu_id);
1807 
1808 	/*
1809 	 * Now we are done with the startup thread, so free it up.
1810 	 */
1811 	thread_exit();
1812 	panic("mp_startup: cannot return");
1813 	/*NOTREACHED*/
1814 }
1815 
1816 /*
1817  * Startup function for 'other' CPUs at boot time (besides boot cpu).
1818  */
1819 static void
1820 mp_startup_boot(void)
1821 {
1822 	mp_startup_common(B_TRUE);
1823 }
1824 
1825 /*
1826  * Startup function for hotplug CPUs at runtime.
1827  */
1828 void
1829 mp_startup_hotplug(void)
1830 {
1831 	mp_startup_common(B_FALSE);
1832 }
1833 
1834 /*
1835  * Start CPU on user request.
1836  */
1837 /* ARGSUSED */
1838 int
1839 mp_cpu_start(struct cpu *cp)
1840 {
1841 	ASSERT(MUTEX_HELD(&cpu_lock));
1842 	return (0);
1843 }
1844 
1845 /*
1846  * Stop CPU on user request.
1847  */
1848 int
1849 mp_cpu_stop(struct cpu *cp)
1850 {
1851 	extern int cbe_psm_timer_mode;
1852 	ASSERT(MUTEX_HELD(&cpu_lock));
1853 
1854 #ifdef __xpv
1855 	/*
1856 	 * We can't offline vcpu0.
1857 	 */
1858 	if (cp->cpu_id == 0)
1859 		return (EBUSY);
1860 #endif
1861 
1862 	/*
1863 	 * If TIMER_PERIODIC mode is used, CPU0 is the one running it;
1864 	 * can't stop it.  (This is true only for machines with no TSC.)
1865 	 */
1866 
1867 	if ((cbe_psm_timer_mode == TIMER_PERIODIC) && (cp->cpu_id == 0))
1868 		return (EBUSY);
1869 
1870 	return (0);
1871 }
1872 
1873 /*
1874  * Take the specified CPU out of participation in interrupts.
1875  */
1876 int
1877 cpu_disable_intr(struct cpu *cp)
1878 {
1879 	if (psm_disable_intr(cp->cpu_id) != DDI_SUCCESS)
1880 		return (EBUSY);
1881 
1882 	cp->cpu_flags &= ~CPU_ENABLE;
1883 	return (0);
1884 }
1885 
1886 /*
1887  * Allow the specified CPU to participate in interrupts.
1888  */
1889 void
1890 cpu_enable_intr(struct cpu *cp)
1891 {
1892 	ASSERT(MUTEX_HELD(&cpu_lock));
1893 	cp->cpu_flags |= CPU_ENABLE;
1894 	psm_enable_intr(cp->cpu_id);
1895 }
1896 
1897 void
1898 mp_cpu_faulted_enter(struct cpu *cp)
1899 {
1900 #ifdef __xpv
1901 	_NOTE(ARGUNUSED(cp));
1902 #else
1903 	cmi_hdl_t hdl = cp->cpu_m.mcpu_cmi_hdl;
1904 
1905 	if (hdl != NULL) {
1906 		cmi_hdl_hold(hdl);
1907 	} else {
1908 		hdl = cmi_hdl_lookup(CMI_HDL_NATIVE, cmi_ntv_hwchipid(cp),
1909 		    cmi_ntv_hwcoreid(cp), cmi_ntv_hwstrandid(cp));
1910 	}
1911 	if (hdl != NULL) {
1912 		cmi_faulted_enter(hdl);
1913 		cmi_hdl_rele(hdl);
1914 	}
1915 #endif
1916 }
1917 
1918 void
1919 mp_cpu_faulted_exit(struct cpu *cp)
1920 {
1921 #ifdef __xpv
1922 	_NOTE(ARGUNUSED(cp));
1923 #else
1924 	cmi_hdl_t hdl = cp->cpu_m.mcpu_cmi_hdl;
1925 
1926 	if (hdl != NULL) {
1927 		cmi_hdl_hold(hdl);
1928 	} else {
1929 		hdl = cmi_hdl_lookup(CMI_HDL_NATIVE, cmi_ntv_hwchipid(cp),
1930 		    cmi_ntv_hwcoreid(cp), cmi_ntv_hwstrandid(cp));
1931 	}
1932 	if (hdl != NULL) {
1933 		cmi_faulted_exit(hdl);
1934 		cmi_hdl_rele(hdl);
1935 	}
1936 #endif
1937 }
1938 
1939 /*
1940  * The following two routines are used as context operators on threads belonging
1941  * to processes with a private LDT (see sysi86).  Due to the rarity of such
1942  * processes, these routines are currently written for best code readability and
1943  * organization rather than speed.  We could avoid checking x86_featureset at
1944  * every context switch by installing different context ops, depending on
1945  * x86_featureset, at LDT creation time -- one for each combination of fast
1946  * syscall features.
1947  */
1948 
1949 /*ARGSUSED*/
1950 void
1951 cpu_fast_syscall_disable(void *arg)
1952 {
1953 	if (is_x86_feature(x86_featureset, X86FSET_MSR) &&
1954 	    is_x86_feature(x86_featureset, X86FSET_SEP))
1955 		cpu_sep_disable();
1956 	if (is_x86_feature(x86_featureset, X86FSET_MSR) &&
1957 	    is_x86_feature(x86_featureset, X86FSET_ASYSC))
1958 		cpu_asysc_disable();
1959 }
1960 
1961 /*ARGSUSED*/
1962 void
1963 cpu_fast_syscall_enable(void *arg)
1964 {
1965 	if (is_x86_feature(x86_featureset, X86FSET_MSR) &&
1966 	    is_x86_feature(x86_featureset, X86FSET_SEP))
1967 		cpu_sep_enable();
1968 	if (is_x86_feature(x86_featureset, X86FSET_MSR) &&
1969 	    is_x86_feature(x86_featureset, X86FSET_ASYSC))
1970 		cpu_asysc_enable();
1971 }
1972 
1973 static void
1974 cpu_sep_enable(void)
1975 {
1976 	ASSERT(is_x86_feature(x86_featureset, X86FSET_SEP));
1977 	ASSERT(curthread->t_preempt || getpil() >= LOCK_LEVEL);
1978 
1979 	wrmsr(MSR_INTC_SEP_CS, (uint64_t)(uintptr_t)KCS_SEL);
1980 }
1981 
1982 static void
1983 cpu_sep_disable(void)
1984 {
1985 	ASSERT(is_x86_feature(x86_featureset, X86FSET_SEP));
1986 	ASSERT(curthread->t_preempt || getpil() >= LOCK_LEVEL);
1987 
1988 	/*
1989 	 * Setting the SYSENTER_CS_MSR register to 0 causes software executing
1990 	 * the sysenter or sysexit instruction to trigger a #gp fault.
1991 	 */
1992 	wrmsr(MSR_INTC_SEP_CS, 0);
1993 }
1994 
1995 static void
1996 cpu_asysc_enable(void)
1997 {
1998 	ASSERT(is_x86_feature(x86_featureset, X86FSET_ASYSC));
1999 	ASSERT(curthread->t_preempt || getpil() >= LOCK_LEVEL);
2000 
2001 	wrmsr(MSR_AMD_EFER, rdmsr(MSR_AMD_EFER) |
2002 	    (uint64_t)(uintptr_t)AMD_EFER_SCE);
2003 }
2004 
2005 static void
2006 cpu_asysc_disable(void)
2007 {
2008 	ASSERT(is_x86_feature(x86_featureset, X86FSET_ASYSC));
2009 	ASSERT(curthread->t_preempt || getpil() >= LOCK_LEVEL);
2010 
2011 	/*
2012 	 * Turn off the SCE (syscall enable) bit in the EFER register. Software
2013 	 * executing syscall or sysret with this bit off will incur a #ud trap.
2014 	 */
2015 	wrmsr(MSR_AMD_EFER, rdmsr(MSR_AMD_EFER) &
2016 	    ~((uint64_t)(uintptr_t)AMD_EFER_SCE));
2017 }
2018