xref: /titanic_52/usr/src/uts/i86pc/os/mp_startup.c (revision ebb8ac078e9265f87093fbb363e8c2cbc6ee13e6)
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  * Copyright (c) 2012, Joyent, Inc.  All rights reserved.
31  */
32 
33 #include <sys/types.h>
34 #include <sys/thread.h>
35 #include <sys/cpuvar.h>
36 #include <sys/cpu.h>
37 #include <sys/t_lock.h>
38 #include <sys/param.h>
39 #include <sys/proc.h>
40 #include <sys/disp.h>
41 #include <sys/class.h>
42 #include <sys/cmn_err.h>
43 #include <sys/debug.h>
44 #include <sys/note.h>
45 #include <sys/asm_linkage.h>
46 #include <sys/x_call.h>
47 #include <sys/systm.h>
48 #include <sys/var.h>
49 #include <sys/vtrace.h>
50 #include <vm/hat.h>
51 #include <vm/as.h>
52 #include <vm/seg_kmem.h>
53 #include <vm/seg_kp.h>
54 #include <sys/segments.h>
55 #include <sys/kmem.h>
56 #include <sys/stack.h>
57 #include <sys/smp_impldefs.h>
58 #include <sys/x86_archext.h>
59 #include <sys/machsystm.h>
60 #include <sys/traptrace.h>
61 #include <sys/clock.h>
62 #include <sys/cpc_impl.h>
63 #include <sys/pg.h>
64 #include <sys/cmt.h>
65 #include <sys/dtrace.h>
66 #include <sys/archsystm.h>
67 #include <sys/fp.h>
68 #include <sys/reboot.h>
69 #include <sys/kdi_machimpl.h>
70 #include <vm/hat_i86.h>
71 #include <vm/vm_dep.h>
72 #include <sys/memnode.h>
73 #include <sys/pci_cfgspace.h>
74 #include <sys/mach_mmu.h>
75 #include <sys/sysmacros.h>
76 #if defined(__xpv)
77 #include <sys/hypervisor.h>
78 #endif
79 #include <sys/cpu_module.h>
80 
81 struct cpu	cpus[1];			/* CPU data */
82 struct cpu	*cpu[NCPU] = {&cpus[0]};	/* pointers to all CPUs */
83 struct cpu	*cpu_free_list;			/* list for released CPUs */
84 cpu_core_t	cpu_core[NCPU];			/* cpu_core structures */
85 
86 #define	cpu_next_free	cpu_prev
87 
88 /*
89  * Useful for disabling MP bring-up on a MP capable system.
90  */
91 int use_mp = 1;
92 
93 /*
94  * to be set by a PSM to indicate what cpus
95  * are sitting around on the system.
96  */
97 cpuset_t mp_cpus;
98 
99 /*
100  * This variable is used by the hat layer to decide whether or not
101  * critical sections are needed to prevent race conditions.  For sun4m,
102  * this variable is set once enough MP initialization has been done in
103  * order to allow cross calls.
104  */
105 int flushes_require_xcalls;
106 
107 cpuset_t cpu_ready_set;		/* initialized in startup() */
108 
109 static void mp_startup_boot(void);
110 static void mp_startup_hotplug(void);
111 
112 static void cpu_sep_enable(void);
113 static void cpu_sep_disable(void);
114 static void cpu_asysc_enable(void);
115 static void cpu_asysc_disable(void);
116 
117 /*
118  * Init CPU info - get CPU type info for processor_info system call.
119  */
120 void
121 init_cpu_info(struct cpu *cp)
122 {
123 	processor_info_t *pi = &cp->cpu_type_info;
124 
125 	/*
126 	 * Get clock-frequency property for the CPU.
127 	 */
128 	pi->pi_clock = cpu_freq;
129 
130 	/*
131 	 * Current frequency in Hz.
132 	 */
133 	cp->cpu_curr_clock = cpu_freq_hz;
134 
135 	/*
136 	 * Supported frequencies.
137 	 */
138 	if (cp->cpu_supp_freqs == NULL) {
139 		cpu_set_supp_freqs(cp, NULL);
140 	}
141 
142 	(void) strcpy(pi->pi_processor_type, "i386");
143 	if (fpu_exists)
144 		(void) strcpy(pi->pi_fputypes, "i387 compatible");
145 
146 	cp->cpu_idstr = kmem_zalloc(CPU_IDSTRLEN, KM_SLEEP);
147 	cp->cpu_brandstr = kmem_zalloc(CPU_IDSTRLEN, KM_SLEEP);
148 
149 	/*
150 	 * If called for the BSP, cp is equal to current CPU.
151 	 * For non-BSPs, cpuid info of cp is not ready yet, so use cpuid info
152 	 * of current CPU as default values for cpu_idstr and cpu_brandstr.
153 	 * They will be corrected in mp_startup_common() after cpuid_pass1()
154 	 * has been invoked on target CPU.
155 	 */
156 	(void) cpuid_getidstr(CPU, cp->cpu_idstr, CPU_IDSTRLEN);
157 	(void) cpuid_getbrandstr(CPU, cp->cpu_brandstr, CPU_IDSTRLEN);
158 }
159 
160 /*
161  * Configure syscall support on this CPU.
162  */
163 /*ARGSUSED*/
164 void
165 init_cpu_syscall(struct cpu *cp)
166 {
167 	kpreempt_disable();
168 
169 #if defined(__amd64)
170 	if (is_x86_feature(x86_featureset, X86FSET_MSR) &&
171 	    is_x86_feature(x86_featureset, X86FSET_ASYSC)) {
172 
173 #if !defined(__lint)
174 		/*
175 		 * The syscall instruction imposes a certain ordering on
176 		 * segment selectors, so we double-check that ordering
177 		 * here.
178 		 */
179 		ASSERT(KDS_SEL == KCS_SEL + 8);
180 		ASSERT(UDS_SEL == U32CS_SEL + 8);
181 		ASSERT(UCS_SEL == U32CS_SEL + 16);
182 #endif
183 		/*
184 		 * Turn syscall/sysret extensions on.
185 		 */
186 		cpu_asysc_enable();
187 
188 		/*
189 		 * Program the magic registers ..
190 		 */
191 		wrmsr(MSR_AMD_STAR,
192 		    ((uint64_t)(U32CS_SEL << 16 | KCS_SEL)) << 32);
193 		wrmsr(MSR_AMD_LSTAR, (uint64_t)(uintptr_t)sys_syscall);
194 		wrmsr(MSR_AMD_CSTAR, (uint64_t)(uintptr_t)sys_syscall32);
195 
196 		/*
197 		 * This list of flags is masked off the incoming
198 		 * %rfl when we enter the kernel.
199 		 */
200 		wrmsr(MSR_AMD_SFMASK, (uint64_t)(uintptr_t)(PS_IE | PS_T));
201 	}
202 #endif
203 
204 	/*
205 	 * On 32-bit kernels, we use sysenter/sysexit because it's too
206 	 * hard to use syscall/sysret, and it is more portable anyway.
207 	 *
208 	 * On 64-bit kernels on Nocona machines, the 32-bit syscall
209 	 * variant isn't available to 32-bit applications, but sysenter is.
210 	 */
211 	if (is_x86_feature(x86_featureset, X86FSET_MSR) &&
212 	    is_x86_feature(x86_featureset, X86FSET_SEP)) {
213 
214 #if !defined(__lint)
215 		/*
216 		 * The sysenter instruction imposes a certain ordering on
217 		 * segment selectors, so we double-check that ordering
218 		 * here. See "sysenter" in Intel document 245471-012, "IA-32
219 		 * Intel Architecture Software Developer's Manual Volume 2:
220 		 * Instruction Set Reference"
221 		 */
222 		ASSERT(KDS_SEL == KCS_SEL + 8);
223 
224 		ASSERT32(UCS_SEL == ((KCS_SEL + 16) | 3));
225 		ASSERT32(UDS_SEL == UCS_SEL + 8);
226 
227 		ASSERT64(U32CS_SEL == ((KCS_SEL + 16) | 3));
228 		ASSERT64(UDS_SEL == U32CS_SEL + 8);
229 #endif
230 
231 		cpu_sep_enable();
232 
233 		/*
234 		 * resume() sets this value to the base of the threads stack
235 		 * via a context handler.
236 		 */
237 		wrmsr(MSR_INTC_SEP_ESP, 0);
238 		wrmsr(MSR_INTC_SEP_EIP, (uint64_t)(uintptr_t)sys_sysenter);
239 	}
240 
241 	kpreempt_enable();
242 }
243 
244 /*
245  * Multiprocessor initialization.
246  *
247  * Allocate and initialize the cpu structure, TRAPTRACE buffer, and the
248  * startup and idle threads for the specified CPU.
249  * Parameter boot is true for boot time operations and is false for CPU
250  * DR operations.
251  */
252 static struct cpu *
253 mp_cpu_configure_common(int cpun, boolean_t boot)
254 {
255 	struct cpu *cp;
256 	kthread_id_t tp;
257 	caddr_t	sp;
258 	proc_t *procp;
259 #if !defined(__xpv)
260 	extern int idle_cpu_prefer_mwait;
261 	extern void cpu_idle_mwait();
262 #endif
263 	extern void idle();
264 	extern void cpu_idle();
265 
266 #ifdef TRAPTRACE
267 	trap_trace_ctl_t *ttc = &trap_trace_ctl[cpun];
268 #endif
269 
270 	ASSERT(MUTEX_HELD(&cpu_lock));
271 	ASSERT(cpun < NCPU && cpu[cpun] == NULL);
272 
273 	if (cpu_free_list == NULL) {
274 		cp = kmem_zalloc(sizeof (*cp), KM_SLEEP);
275 	} else {
276 		cp = cpu_free_list;
277 		cpu_free_list = cp->cpu_next_free;
278 	}
279 
280 	cp->cpu_m.mcpu_istamp = cpun << 16;
281 
282 	/* Create per CPU specific threads in the process p0. */
283 	procp = &p0;
284 
285 	/*
286 	 * Initialize the dispatcher first.
287 	 */
288 	disp_cpu_init(cp);
289 
290 	cpu_vm_data_init(cp);
291 
292 	/*
293 	 * Allocate and initialize the startup thread for this CPU.
294 	 * Interrupt and process switch stacks get allocated later
295 	 * when the CPU starts running.
296 	 */
297 	tp = thread_create(NULL, 0, NULL, NULL, 0, procp,
298 	    TS_STOPPED, maxclsyspri);
299 
300 	/*
301 	 * Set state to TS_ONPROC since this thread will start running
302 	 * as soon as the CPU comes online.
303 	 *
304 	 * All the other fields of the thread structure are setup by
305 	 * thread_create().
306 	 */
307 	THREAD_ONPROC(tp, cp);
308 	tp->t_preempt = 1;
309 	tp->t_bound_cpu = cp;
310 	tp->t_affinitycnt = 1;
311 	tp->t_cpu = cp;
312 	tp->t_disp_queue = cp->cpu_disp;
313 
314 	/*
315 	 * Setup thread to start in mp_startup_common.
316 	 */
317 	sp = tp->t_stk;
318 	tp->t_sp = (uintptr_t)(sp - MINFRAME);
319 #if defined(__amd64)
320 	tp->t_sp -= STACK_ENTRY_ALIGN;		/* fake a call */
321 #endif
322 	/*
323 	 * Setup thread start entry point for boot or hotplug.
324 	 */
325 	if (boot) {
326 		tp->t_pc = (uintptr_t)mp_startup_boot;
327 	} else {
328 		tp->t_pc = (uintptr_t)mp_startup_hotplug;
329 	}
330 
331 	cp->cpu_id = cpun;
332 	cp->cpu_self = cp;
333 	cp->cpu_thread = tp;
334 	cp->cpu_lwp = NULL;
335 	cp->cpu_dispthread = tp;
336 	cp->cpu_dispatch_pri = DISP_PRIO(tp);
337 
338 	/*
339 	 * cpu_base_spl must be set explicitly here to prevent any blocking
340 	 * operations in mp_startup_common from causing the spl of the cpu
341 	 * to drop to 0 (allowing device interrupts before we're ready) in
342 	 * resume().
343 	 * cpu_base_spl MUST remain at LOCK_LEVEL until the cpu is CPU_READY.
344 	 * As an extra bit of security on DEBUG kernels, this is enforced with
345 	 * an assertion in mp_startup_common() -- before cpu_base_spl is set
346 	 * to its proper value.
347 	 */
348 	cp->cpu_base_spl = ipltospl(LOCK_LEVEL);
349 
350 	/*
351 	 * Now, initialize per-CPU idle thread for this CPU.
352 	 */
353 	tp = thread_create(NULL, PAGESIZE, idle, NULL, 0, procp, TS_ONPROC, -1);
354 
355 	cp->cpu_idle_thread = tp;
356 
357 	tp->t_preempt = 1;
358 	tp->t_bound_cpu = cp;
359 	tp->t_affinitycnt = 1;
360 	tp->t_cpu = cp;
361 	tp->t_disp_queue = cp->cpu_disp;
362 
363 	/*
364 	 * Bootstrap the CPU's PG data
365 	 */
366 	pg_cpu_bootstrap(cp);
367 
368 	/*
369 	 * Perform CPC initialization on the new CPU.
370 	 */
371 	kcpc_hw_init(cp);
372 
373 	/*
374 	 * Allocate virtual addresses for cpu_caddr1 and cpu_caddr2
375 	 * for each CPU.
376 	 */
377 	setup_vaddr_for_ppcopy(cp);
378 
379 	/*
380 	 * Allocate page for new GDT and initialize from current GDT.
381 	 */
382 #if !defined(__lint)
383 	ASSERT((sizeof (*cp->cpu_gdt) * NGDT) <= PAGESIZE);
384 #endif
385 	cp->cpu_gdt = kmem_zalloc(PAGESIZE, KM_SLEEP);
386 	bcopy(CPU->cpu_gdt, cp->cpu_gdt, (sizeof (*cp->cpu_gdt) * NGDT));
387 
388 #if defined(__i386)
389 	/*
390 	 * setup kernel %gs.
391 	 */
392 	set_usegd(&cp->cpu_gdt[GDT_GS], cp, sizeof (struct cpu) -1, SDT_MEMRWA,
393 	    SEL_KPL, 0, 1);
394 #endif
395 
396 	/*
397 	 * If we have more than one node, each cpu gets a copy of IDT
398 	 * local to its node. If this is a Pentium box, we use cpu 0's
399 	 * IDT. cpu 0's IDT has been made read-only to workaround the
400 	 * cmpxchgl register bug
401 	 */
402 	if (system_hardware.hd_nodes && x86_type != X86_TYPE_P5) {
403 #if !defined(__lint)
404 		ASSERT((sizeof (*CPU->cpu_idt) * NIDT) <= PAGESIZE);
405 #endif
406 		cp->cpu_idt = kmem_zalloc(PAGESIZE, KM_SLEEP);
407 		bcopy(CPU->cpu_idt, cp->cpu_idt, PAGESIZE);
408 	} else {
409 		cp->cpu_idt = CPU->cpu_idt;
410 	}
411 
412 	/*
413 	 * Get interrupt priority data from cpu 0.
414 	 */
415 	cp->cpu_pri_data = CPU->cpu_pri_data;
416 
417 	/*
418 	 * alloc space for cpuid info
419 	 */
420 	cpuid_alloc_space(cp);
421 #if !defined(__xpv)
422 	if (is_x86_feature(x86_featureset, X86FSET_MWAIT) &&
423 	    idle_cpu_prefer_mwait) {
424 		cp->cpu_m.mcpu_mwait = cpuid_mwait_alloc(cp);
425 		cp->cpu_m.mcpu_idle_cpu = cpu_idle_mwait;
426 	} else
427 #endif
428 		cp->cpu_m.mcpu_idle_cpu = cpu_idle;
429 
430 	init_cpu_info(cp);
431 
432 	/*
433 	 * alloc space for ucode_info
434 	 */
435 	ucode_alloc_space(cp);
436 	xc_init_cpu(cp);
437 	hat_cpu_online(cp);
438 
439 #ifdef TRAPTRACE
440 	/*
441 	 * If this is a TRAPTRACE kernel, allocate TRAPTRACE buffers
442 	 */
443 	ttc->ttc_first = (uintptr_t)kmem_zalloc(trap_trace_bufsize, KM_SLEEP);
444 	ttc->ttc_next = ttc->ttc_first;
445 	ttc->ttc_limit = ttc->ttc_first + trap_trace_bufsize;
446 #endif
447 
448 	/*
449 	 * Record that we have another CPU.
450 	 */
451 	/*
452 	 * Initialize the interrupt threads for this CPU
453 	 */
454 	cpu_intr_alloc(cp, NINTR_THREADS);
455 
456 	cp->cpu_flags = CPU_OFFLINE | CPU_QUIESCED | CPU_POWEROFF;
457 	cpu_set_state(cp);
458 
459 	/*
460 	 * Add CPU to list of available CPUs.  It'll be on the active list
461 	 * after mp_startup_common().
462 	 */
463 	cpu_add_unit(cp);
464 
465 	return (cp);
466 }
467 
468 /*
469  * Undo what was done in mp_cpu_configure_common
470  */
471 static void
472 mp_cpu_unconfigure_common(struct cpu *cp, int error)
473 {
474 	ASSERT(MUTEX_HELD(&cpu_lock));
475 
476 	/*
477 	 * Remove the CPU from the list of available CPUs.
478 	 */
479 	cpu_del_unit(cp->cpu_id);
480 
481 	if (error == ETIMEDOUT) {
482 		/*
483 		 * The cpu was started, but never *seemed* to run any
484 		 * code in the kernel; it's probably off spinning in its
485 		 * own private world, though with potential references to
486 		 * our kmem-allocated IDTs and GDTs (for example).
487 		 *
488 		 * Worse still, it may actually wake up some time later,
489 		 * so rather than guess what it might or might not do, we
490 		 * leave the fundamental data structures intact.
491 		 */
492 		cp->cpu_flags = 0;
493 		return;
494 	}
495 
496 	/*
497 	 * At this point, the only threads bound to this CPU should
498 	 * special per-cpu threads: it's idle thread, it's pause threads,
499 	 * and it's interrupt threads.  Clean these up.
500 	 */
501 	cpu_destroy_bound_threads(cp);
502 	cp->cpu_idle_thread = NULL;
503 
504 	/*
505 	 * Free the interrupt stack.
506 	 */
507 	segkp_release(segkp,
508 	    cp->cpu_intr_stack - (INTR_STACK_SIZE - SA(MINFRAME)));
509 	cp->cpu_intr_stack = NULL;
510 
511 #ifdef TRAPTRACE
512 	/*
513 	 * Discard the trap trace buffer
514 	 */
515 	{
516 		trap_trace_ctl_t *ttc = &trap_trace_ctl[cp->cpu_id];
517 
518 		kmem_free((void *)ttc->ttc_first, trap_trace_bufsize);
519 		ttc->ttc_first = NULL;
520 	}
521 #endif
522 
523 	hat_cpu_offline(cp);
524 
525 	ucode_free_space(cp);
526 
527 	/* Free CPU ID string and brand string. */
528 	if (cp->cpu_idstr) {
529 		kmem_free(cp->cpu_idstr, CPU_IDSTRLEN);
530 		cp->cpu_idstr = NULL;
531 	}
532 	if (cp->cpu_brandstr) {
533 		kmem_free(cp->cpu_brandstr, CPU_IDSTRLEN);
534 		cp->cpu_brandstr = NULL;
535 	}
536 
537 #if !defined(__xpv)
538 	if (cp->cpu_m.mcpu_mwait != NULL) {
539 		cpuid_mwait_free(cp);
540 		cp->cpu_m.mcpu_mwait = NULL;
541 	}
542 #endif
543 	cpuid_free_space(cp);
544 
545 	if (cp->cpu_idt != CPU->cpu_idt)
546 		kmem_free(cp->cpu_idt, PAGESIZE);
547 	cp->cpu_idt = NULL;
548 
549 	kmem_free(cp->cpu_gdt, PAGESIZE);
550 	cp->cpu_gdt = NULL;
551 
552 	if (cp->cpu_supp_freqs != NULL) {
553 		size_t len = strlen(cp->cpu_supp_freqs) + 1;
554 		kmem_free(cp->cpu_supp_freqs, len);
555 		cp->cpu_supp_freqs = NULL;
556 	}
557 
558 	teardown_vaddr_for_ppcopy(cp);
559 
560 	kcpc_hw_fini(cp);
561 
562 	cp->cpu_dispthread = NULL;
563 	cp->cpu_thread = NULL;	/* discarded by cpu_destroy_bound_threads() */
564 
565 	cpu_vm_data_destroy(cp);
566 
567 	xc_fini_cpu(cp);
568 	disp_cpu_fini(cp);
569 
570 	ASSERT(cp != CPU0);
571 	bzero(cp, sizeof (*cp));
572 	cp->cpu_next_free = cpu_free_list;
573 	cpu_free_list = cp;
574 }
575 
576 /*
577  * Apply workarounds for known errata, and warn about those that are absent.
578  *
579  * System vendors occasionally create configurations which contain different
580  * revisions of the CPUs that are almost but not exactly the same.  At the
581  * time of writing, this meant that their clock rates were the same, their
582  * feature sets were the same, but the required workaround were -not-
583  * necessarily the same.  So, this routine is invoked on -every- CPU soon
584  * after starting to make sure that the resulting system contains the most
585  * pessimal set of workarounds needed to cope with *any* of the CPUs in the
586  * system.
587  *
588  * workaround_errata is invoked early in mlsetup() for CPU 0, and in
589  * mp_startup_common() for all slave CPUs. Slaves process workaround_errata
590  * prior to acknowledging their readiness to the master, so this routine will
591  * never be executed by multiple CPUs in parallel, thus making updates to
592  * global data safe.
593  *
594  * These workarounds are based on Rev 3.57 of the Revision Guide for
595  * AMD Athlon(tm) 64 and AMD Opteron(tm) Processors, August 2005.
596  */
597 
598 #if defined(OPTERON_ERRATUM_88)
599 int opteron_erratum_88;		/* if non-zero -> at least one cpu has it */
600 #endif
601 
602 #if defined(OPTERON_ERRATUM_91)
603 int opteron_erratum_91;		/* if non-zero -> at least one cpu has it */
604 #endif
605 
606 #if defined(OPTERON_ERRATUM_93)
607 int opteron_erratum_93;		/* if non-zero -> at least one cpu has it */
608 #endif
609 
610 #if defined(OPTERON_ERRATUM_95)
611 int opteron_erratum_95;		/* if non-zero -> at least one cpu has it */
612 #endif
613 
614 #if defined(OPTERON_ERRATUM_100)
615 int opteron_erratum_100;	/* if non-zero -> at least one cpu has it */
616 #endif
617 
618 #if defined(OPTERON_ERRATUM_108)
619 int opteron_erratum_108;	/* if non-zero -> at least one cpu has it */
620 #endif
621 
622 #if defined(OPTERON_ERRATUM_109)
623 int opteron_erratum_109;	/* if non-zero -> at least one cpu has it */
624 #endif
625 
626 #if defined(OPTERON_ERRATUM_121)
627 int opteron_erratum_121;	/* if non-zero -> at least one cpu has it */
628 #endif
629 
630 #if defined(OPTERON_ERRATUM_122)
631 int opteron_erratum_122;	/* if non-zero -> at least one cpu has it */
632 #endif
633 
634 #if defined(OPTERON_ERRATUM_123)
635 int opteron_erratum_123;	/* if non-zero -> at least one cpu has it */
636 #endif
637 
638 #if defined(OPTERON_ERRATUM_131)
639 int opteron_erratum_131;	/* if non-zero -> at least one cpu has it */
640 #endif
641 
642 #if defined(OPTERON_WORKAROUND_6336786)
643 int opteron_workaround_6336786;	/* non-zero -> WA relevant and applied */
644 int opteron_workaround_6336786_UP = 0;	/* Not needed for UP */
645 #endif
646 
647 #if defined(OPTERON_WORKAROUND_6323525)
648 int opteron_workaround_6323525;	/* if non-zero -> at least one cpu has it */
649 #endif
650 
651 #if defined(OPTERON_ERRATUM_298)
652 int opteron_erratum_298;
653 #endif
654 
655 #if defined(OPTERON_ERRATUM_721)
656 int opteron_erratum_721;
657 #endif
658 
659 static void
660 workaround_warning(cpu_t *cp, uint_t erratum)
661 {
662 	cmn_err(CE_WARN, "cpu%d: no workaround for erratum %u",
663 	    cp->cpu_id, erratum);
664 }
665 
666 static void
667 workaround_applied(uint_t erratum)
668 {
669 	if (erratum > 1000000)
670 		cmn_err(CE_CONT, "?workaround applied for cpu issue #%d\n",
671 		    erratum);
672 	else
673 		cmn_err(CE_CONT, "?workaround applied for cpu erratum #%d\n",
674 		    erratum);
675 }
676 
677 static void
678 msr_warning(cpu_t *cp, const char *rw, uint_t msr, int error)
679 {
680 	cmn_err(CE_WARN, "cpu%d: couldn't %smsr 0x%x, error %d",
681 	    cp->cpu_id, rw, msr, error);
682 }
683 
684 /*
685  * Determine the number of nodes in a Hammer / Greyhound / Griffin family
686  * system.
687  */
688 static uint_t
689 opteron_get_nnodes(void)
690 {
691 	static uint_t nnodes = 0;
692 
693 	if (nnodes == 0) {
694 #ifdef	DEBUG
695 		uint_t family;
696 
697 		/*
698 		 * This routine uses a PCI config space based mechanism
699 		 * for retrieving the number of nodes in the system.
700 		 * Device 24, function 0, offset 0x60 as used here is not
701 		 * AMD processor architectural, and may not work on processor
702 		 * families other than those listed below.
703 		 *
704 		 * Callers of this routine must ensure that we're running on
705 		 * a processor which supports this mechanism.
706 		 * The assertion below is meant to catch calls on unsupported
707 		 * processors.
708 		 */
709 		family = cpuid_getfamily(CPU);
710 		ASSERT(family == 0xf || family == 0x10 || family == 0x11);
711 #endif	/* DEBUG */
712 
713 		/*
714 		 * Obtain the number of nodes in the system from
715 		 * bits [6:4] of the Node ID register on node 0.
716 		 *
717 		 * The actual node count is NodeID[6:4] + 1
718 		 *
719 		 * The Node ID register is accessed via function 0,
720 		 * offset 0x60. Node 0 is device 24.
721 		 */
722 		nnodes = ((pci_getl_func(0, 24, 0, 0x60) & 0x70) >> 4) + 1;
723 	}
724 	return (nnodes);
725 }
726 
727 uint_t
728 do_erratum_298(struct cpu *cpu)
729 {
730 	static int	osvwrc = -3;
731 	extern int	osvw_opteron_erratum(cpu_t *, uint_t);
732 
733 	/*
734 	 * L2 Eviction May Occur During Processor Operation To Set
735 	 * Accessed or Dirty Bit.
736 	 */
737 	if (osvwrc == -3) {
738 		osvwrc = osvw_opteron_erratum(cpu, 298);
739 	} else {
740 		/* osvw return codes should be consistent for all cpus */
741 		ASSERT(osvwrc == osvw_opteron_erratum(cpu, 298));
742 	}
743 
744 	switch (osvwrc) {
745 	case 0:		/* erratum is not present: do nothing */
746 		break;
747 	case 1:		/* erratum is present: BIOS workaround applied */
748 		/*
749 		 * check if workaround is actually in place and issue warning
750 		 * if not.
751 		 */
752 		if (((rdmsr(MSR_AMD_HWCR) & AMD_HWCR_TLBCACHEDIS) == 0) ||
753 		    ((rdmsr(MSR_AMD_BU_CFG) & AMD_BU_CFG_E298) == 0)) {
754 #if defined(OPTERON_ERRATUM_298)
755 			opteron_erratum_298++;
756 #else
757 			workaround_warning(cpu, 298);
758 			return (1);
759 #endif
760 		}
761 		break;
762 	case -1:	/* cannot determine via osvw: check cpuid */
763 		if ((cpuid_opteron_erratum(cpu, 298) > 0) &&
764 		    (((rdmsr(MSR_AMD_HWCR) & AMD_HWCR_TLBCACHEDIS) == 0) ||
765 		    ((rdmsr(MSR_AMD_BU_CFG) & AMD_BU_CFG_E298) == 0))) {
766 #if defined(OPTERON_ERRATUM_298)
767 			opteron_erratum_298++;
768 #else
769 			workaround_warning(cpu, 298);
770 			return (1);
771 #endif
772 		}
773 		break;
774 	}
775 	return (0);
776 }
777 
778 uint_t
779 workaround_errata(struct cpu *cpu)
780 {
781 	uint_t missing = 0;
782 
783 	ASSERT(cpu == CPU);
784 
785 	/*LINTED*/
786 	if (cpuid_opteron_erratum(cpu, 88) > 0) {
787 		/*
788 		 * SWAPGS May Fail To Read Correct GS Base
789 		 */
790 #if defined(OPTERON_ERRATUM_88)
791 		/*
792 		 * The workaround is an mfence in the relevant assembler code
793 		 */
794 		opteron_erratum_88++;
795 #else
796 		workaround_warning(cpu, 88);
797 		missing++;
798 #endif
799 	}
800 
801 	if (cpuid_opteron_erratum(cpu, 91) > 0) {
802 		/*
803 		 * Software Prefetches May Report A Page Fault
804 		 */
805 #if defined(OPTERON_ERRATUM_91)
806 		/*
807 		 * fix is in trap.c
808 		 */
809 		opteron_erratum_91++;
810 #else
811 		workaround_warning(cpu, 91);
812 		missing++;
813 #endif
814 	}
815 
816 	if (cpuid_opteron_erratum(cpu, 93) > 0) {
817 		/*
818 		 * RSM Auto-Halt Restart Returns to Incorrect RIP
819 		 */
820 #if defined(OPTERON_ERRATUM_93)
821 		/*
822 		 * fix is in trap.c
823 		 */
824 		opteron_erratum_93++;
825 #else
826 		workaround_warning(cpu, 93);
827 		missing++;
828 #endif
829 	}
830 
831 	/*LINTED*/
832 	if (cpuid_opteron_erratum(cpu, 95) > 0) {
833 		/*
834 		 * RET Instruction May Return to Incorrect EIP
835 		 */
836 #if defined(OPTERON_ERRATUM_95)
837 #if defined(_LP64)
838 		/*
839 		 * Workaround this by ensuring that 32-bit user code and
840 		 * 64-bit kernel code never occupy the same address
841 		 * range mod 4G.
842 		 */
843 		if (_userlimit32 > 0xc0000000ul)
844 			*(uintptr_t *)&_userlimit32 = 0xc0000000ul;
845 
846 		/*LINTED*/
847 		ASSERT((uint32_t)COREHEAP_BASE == 0xc0000000u);
848 		opteron_erratum_95++;
849 #endif	/* _LP64 */
850 #else
851 		workaround_warning(cpu, 95);
852 		missing++;
853 #endif
854 	}
855 
856 	if (cpuid_opteron_erratum(cpu, 100) > 0) {
857 		/*
858 		 * Compatibility Mode Branches Transfer to Illegal Address
859 		 */
860 #if defined(OPTERON_ERRATUM_100)
861 		/*
862 		 * fix is in trap.c
863 		 */
864 		opteron_erratum_100++;
865 #else
866 		workaround_warning(cpu, 100);
867 		missing++;
868 #endif
869 	}
870 
871 	/*LINTED*/
872 	if (cpuid_opteron_erratum(cpu, 108) > 0) {
873 		/*
874 		 * CPUID Instruction May Return Incorrect Model Number In
875 		 * Some Processors
876 		 */
877 #if defined(OPTERON_ERRATUM_108)
878 		/*
879 		 * (Our cpuid-handling code corrects the model number on
880 		 * those processors)
881 		 */
882 #else
883 		workaround_warning(cpu, 108);
884 		missing++;
885 #endif
886 	}
887 
888 	/*LINTED*/
889 	if (cpuid_opteron_erratum(cpu, 109) > 0) do {
890 		/*
891 		 * Certain Reverse REP MOVS May Produce Unpredictable Behavior
892 		 */
893 #if defined(OPTERON_ERRATUM_109)
894 		/*
895 		 * The "workaround" is to print a warning to upgrade the BIOS
896 		 */
897 		uint64_t value;
898 		const uint_t msr = MSR_AMD_PATCHLEVEL;
899 		int err;
900 
901 		if ((err = checked_rdmsr(msr, &value)) != 0) {
902 			msr_warning(cpu, "rd", msr, err);
903 			workaround_warning(cpu, 109);
904 			missing++;
905 		}
906 		if (value == 0)
907 			opteron_erratum_109++;
908 #else
909 		workaround_warning(cpu, 109);
910 		missing++;
911 #endif
912 	/*CONSTANTCONDITION*/
913 	} while (0);
914 
915 	/*LINTED*/
916 	if (cpuid_opteron_erratum(cpu, 121) > 0) {
917 		/*
918 		 * Sequential Execution Across Non_Canonical Boundary Caused
919 		 * Processor Hang
920 		 */
921 #if defined(OPTERON_ERRATUM_121)
922 #if defined(_LP64)
923 		/*
924 		 * Erratum 121 is only present in long (64 bit) mode.
925 		 * Workaround is to include the page immediately before the
926 		 * va hole to eliminate the possibility of system hangs due to
927 		 * sequential execution across the va hole boundary.
928 		 */
929 		if (opteron_erratum_121)
930 			opteron_erratum_121++;
931 		else {
932 			if (hole_start) {
933 				hole_start -= PAGESIZE;
934 			} else {
935 				/*
936 				 * hole_start not yet initialized by
937 				 * mmu_init. Initialize hole_start
938 				 * with value to be subtracted.
939 				 */
940 				hole_start = PAGESIZE;
941 			}
942 			opteron_erratum_121++;
943 		}
944 #endif	/* _LP64 */
945 #else
946 		workaround_warning(cpu, 121);
947 		missing++;
948 #endif
949 	}
950 
951 	/*LINTED*/
952 	if (cpuid_opteron_erratum(cpu, 122) > 0) do {
953 		/*
954 		 * TLB Flush Filter May Cause Coherency Problem in
955 		 * Multiprocessor Systems
956 		 */
957 #if defined(OPTERON_ERRATUM_122)
958 		uint64_t value;
959 		const uint_t msr = MSR_AMD_HWCR;
960 		int error;
961 
962 		/*
963 		 * Erratum 122 is only present in MP configurations (multi-core
964 		 * or multi-processor).
965 		 */
966 #if defined(__xpv)
967 		if (!DOMAIN_IS_INITDOMAIN(xen_info))
968 			break;
969 		if (!opteron_erratum_122 && xpv_nr_phys_cpus() == 1)
970 			break;
971 #else
972 		if (!opteron_erratum_122 && opteron_get_nnodes() == 1 &&
973 		    cpuid_get_ncpu_per_chip(cpu) == 1)
974 			break;
975 #endif
976 		/* disable TLB Flush Filter */
977 
978 		if ((error = checked_rdmsr(msr, &value)) != 0) {
979 			msr_warning(cpu, "rd", msr, error);
980 			workaround_warning(cpu, 122);
981 			missing++;
982 		} else {
983 			value |= (uint64_t)AMD_HWCR_FFDIS;
984 			if ((error = checked_wrmsr(msr, value)) != 0) {
985 				msr_warning(cpu, "wr", msr, error);
986 				workaround_warning(cpu, 122);
987 				missing++;
988 			}
989 		}
990 		opteron_erratum_122++;
991 #else
992 		workaround_warning(cpu, 122);
993 		missing++;
994 #endif
995 	/*CONSTANTCONDITION*/
996 	} while (0);
997 
998 	/*LINTED*/
999 	if (cpuid_opteron_erratum(cpu, 123) > 0) do {
1000 		/*
1001 		 * Bypassed Reads May Cause Data Corruption of System Hang in
1002 		 * Dual Core Processors
1003 		 */
1004 #if defined(OPTERON_ERRATUM_123)
1005 		uint64_t value;
1006 		const uint_t msr = MSR_AMD_PATCHLEVEL;
1007 		int err;
1008 
1009 		/*
1010 		 * Erratum 123 applies only to multi-core cpus.
1011 		 */
1012 		if (cpuid_get_ncpu_per_chip(cpu) < 2)
1013 			break;
1014 #if defined(__xpv)
1015 		if (!DOMAIN_IS_INITDOMAIN(xen_info))
1016 			break;
1017 #endif
1018 		/*
1019 		 * The "workaround" is to print a warning to upgrade the BIOS
1020 		 */
1021 		if ((err = checked_rdmsr(msr, &value)) != 0) {
1022 			msr_warning(cpu, "rd", msr, err);
1023 			workaround_warning(cpu, 123);
1024 			missing++;
1025 		}
1026 		if (value == 0)
1027 			opteron_erratum_123++;
1028 #else
1029 		workaround_warning(cpu, 123);
1030 		missing++;
1031 
1032 #endif
1033 	/*CONSTANTCONDITION*/
1034 	} while (0);
1035 
1036 	/*LINTED*/
1037 	if (cpuid_opteron_erratum(cpu, 131) > 0) do {
1038 		/*
1039 		 * Multiprocessor Systems with Four or More Cores May Deadlock
1040 		 * Waiting for a Probe Response
1041 		 */
1042 #if defined(OPTERON_ERRATUM_131)
1043 		uint64_t nbcfg;
1044 		const uint_t msr = MSR_AMD_NB_CFG;
1045 		const uint64_t wabits =
1046 		    AMD_NB_CFG_SRQ_HEARTBEAT | AMD_NB_CFG_SRQ_SPR;
1047 		int error;
1048 
1049 		/*
1050 		 * Erratum 131 applies to any system with four or more cores.
1051 		 */
1052 		if (opteron_erratum_131)
1053 			break;
1054 #if defined(__xpv)
1055 		if (!DOMAIN_IS_INITDOMAIN(xen_info))
1056 			break;
1057 		if (xpv_nr_phys_cpus() < 4)
1058 			break;
1059 #else
1060 		if (opteron_get_nnodes() * cpuid_get_ncpu_per_chip(cpu) < 4)
1061 			break;
1062 #endif
1063 		/*
1064 		 * Print a warning if neither of the workarounds for
1065 		 * erratum 131 is present.
1066 		 */
1067 		if ((error = checked_rdmsr(msr, &nbcfg)) != 0) {
1068 			msr_warning(cpu, "rd", msr, error);
1069 			workaround_warning(cpu, 131);
1070 			missing++;
1071 		} else if ((nbcfg & wabits) == 0) {
1072 			opteron_erratum_131++;
1073 		} else {
1074 			/* cannot have both workarounds set */
1075 			ASSERT((nbcfg & wabits) != wabits);
1076 		}
1077 #else
1078 		workaround_warning(cpu, 131);
1079 		missing++;
1080 #endif
1081 	/*CONSTANTCONDITION*/
1082 	} while (0);
1083 
1084 	/*
1085 	 * This isn't really an erratum, but for convenience the
1086 	 * detection/workaround code lives here and in cpuid_opteron_erratum.
1087 	 */
1088 	if (cpuid_opteron_erratum(cpu, 6336786) > 0) {
1089 #if defined(OPTERON_WORKAROUND_6336786)
1090 		/*
1091 		 * Disable C1-Clock ramping on multi-core/multi-processor
1092 		 * K8 platforms to guard against TSC drift.
1093 		 */
1094 		if (opteron_workaround_6336786) {
1095 			opteron_workaround_6336786++;
1096 #if defined(__xpv)
1097 		} else if ((DOMAIN_IS_INITDOMAIN(xen_info) &&
1098 		    xpv_nr_phys_cpus() > 1) ||
1099 		    opteron_workaround_6336786_UP) {
1100 			/*
1101 			 * XXPV	Hmm.  We can't walk the Northbridges on
1102 			 *	the hypervisor; so just complain and drive
1103 			 *	on.  This probably needs to be fixed in
1104 			 *	the hypervisor itself.
1105 			 */
1106 			opteron_workaround_6336786++;
1107 			workaround_warning(cpu, 6336786);
1108 #else	/* __xpv */
1109 		} else if ((opteron_get_nnodes() *
1110 		    cpuid_get_ncpu_per_chip(cpu) > 1) ||
1111 		    opteron_workaround_6336786_UP) {
1112 
1113 			uint_t	node, nnodes;
1114 			uint8_t data;
1115 
1116 			nnodes = opteron_get_nnodes();
1117 			for (node = 0; node < nnodes; node++) {
1118 				/*
1119 				 * Clear PMM7[1:0] (function 3, offset 0x87)
1120 				 * Northbridge device is the node id + 24.
1121 				 */
1122 				data = pci_getb_func(0, node + 24, 3, 0x87);
1123 				data &= 0xFC;
1124 				pci_putb_func(0, node + 24, 3, 0x87, data);
1125 			}
1126 			opteron_workaround_6336786++;
1127 #endif	/* __xpv */
1128 		}
1129 #else
1130 		workaround_warning(cpu, 6336786);
1131 		missing++;
1132 #endif
1133 	}
1134 
1135 	/*LINTED*/
1136 	/*
1137 	 * Mutex primitives don't work as expected.
1138 	 */
1139 	if (cpuid_opteron_erratum(cpu, 6323525) > 0) {
1140 #if defined(OPTERON_WORKAROUND_6323525)
1141 		/*
1142 		 * This problem only occurs with 2 or more cores. If bit in
1143 		 * MSR_AMD_BU_CFG set, then not applicable. The workaround
1144 		 * is to patch the semaphone routines with the lfence
1145 		 * instruction to provide necessary load memory barrier with
1146 		 * possible subsequent read-modify-write ops.
1147 		 *
1148 		 * It is too early in boot to call the patch routine so
1149 		 * set erratum variable to be done in startup_end().
1150 		 */
1151 		if (opteron_workaround_6323525) {
1152 			opteron_workaround_6323525++;
1153 #if defined(__xpv)
1154 		} else if (is_x86_feature(x86_featureset, X86FSET_SSE2)) {
1155 			if (DOMAIN_IS_INITDOMAIN(xen_info)) {
1156 				/*
1157 				 * XXPV	Use dom0_msr here when extended
1158 				 *	operations are supported?
1159 				 */
1160 				if (xpv_nr_phys_cpus() > 1)
1161 					opteron_workaround_6323525++;
1162 			} else {
1163 				/*
1164 				 * We have no way to tell how many physical
1165 				 * cpus there are, or even if this processor
1166 				 * has the problem, so enable the workaround
1167 				 * unconditionally (at some performance cost).
1168 				 */
1169 				opteron_workaround_6323525++;
1170 			}
1171 #else	/* __xpv */
1172 		} else if (is_x86_feature(x86_featureset, X86FSET_SSE2) &&
1173 		    ((opteron_get_nnodes() *
1174 		    cpuid_get_ncpu_per_chip(cpu)) > 1)) {
1175 			if ((xrdmsr(MSR_AMD_BU_CFG) & (UINT64_C(1) << 33)) == 0)
1176 				opteron_workaround_6323525++;
1177 #endif	/* __xpv */
1178 		}
1179 #else
1180 		workaround_warning(cpu, 6323525);
1181 		missing++;
1182 #endif
1183 	}
1184 
1185 	missing += do_erratum_298(cpu);
1186 
1187 	if (cpuid_opteron_erratum(cpu, 721) > 0) {
1188 #if defined(OPTERON_ERRATUM_721)
1189 		wrmsr(MSR_AMD_DE_CFG, rdmsr(MSR_AMD_DE_CFG) | AMD_DE_CFG_E721);
1190 		opteron_erratum_721++;
1191 #else
1192 		workaround_warning(cpu, 721);
1193 		missing++;
1194 #endif
1195 	}
1196 
1197 #ifdef __xpv
1198 	return (0);
1199 #else
1200 	return (missing);
1201 #endif
1202 }
1203 
1204 void
1205 workaround_errata_end()
1206 {
1207 #if defined(OPTERON_ERRATUM_88)
1208 	if (opteron_erratum_88)
1209 		workaround_applied(88);
1210 #endif
1211 #if defined(OPTERON_ERRATUM_91)
1212 	if (opteron_erratum_91)
1213 		workaround_applied(91);
1214 #endif
1215 #if defined(OPTERON_ERRATUM_93)
1216 	if (opteron_erratum_93)
1217 		workaround_applied(93);
1218 #endif
1219 #if defined(OPTERON_ERRATUM_95)
1220 	if (opteron_erratum_95)
1221 		workaround_applied(95);
1222 #endif
1223 #if defined(OPTERON_ERRATUM_100)
1224 	if (opteron_erratum_100)
1225 		workaround_applied(100);
1226 #endif
1227 #if defined(OPTERON_ERRATUM_108)
1228 	if (opteron_erratum_108)
1229 		workaround_applied(108);
1230 #endif
1231 #if defined(OPTERON_ERRATUM_109)
1232 	if (opteron_erratum_109) {
1233 		cmn_err(CE_WARN,
1234 		    "BIOS microcode patch for AMD Athlon(tm) 64/Opteron(tm)"
1235 		    " processor\nerratum 109 was not detected; updating your"
1236 		    " system's BIOS to a version\ncontaining this"
1237 		    " microcode patch is HIGHLY recommended or erroneous"
1238 		    " system\noperation may occur.\n");
1239 	}
1240 #endif
1241 #if defined(OPTERON_ERRATUM_121)
1242 	if (opteron_erratum_121)
1243 		workaround_applied(121);
1244 #endif
1245 #if defined(OPTERON_ERRATUM_122)
1246 	if (opteron_erratum_122)
1247 		workaround_applied(122);
1248 #endif
1249 #if defined(OPTERON_ERRATUM_123)
1250 	if (opteron_erratum_123) {
1251 		cmn_err(CE_WARN,
1252 		    "BIOS microcode patch for AMD Athlon(tm) 64/Opteron(tm)"
1253 		    " processor\nerratum 123 was not detected; updating your"
1254 		    " system's BIOS to a version\ncontaining this"
1255 		    " microcode patch is HIGHLY recommended or erroneous"
1256 		    " system\noperation may occur.\n");
1257 	}
1258 #endif
1259 #if defined(OPTERON_ERRATUM_131)
1260 	if (opteron_erratum_131) {
1261 		cmn_err(CE_WARN,
1262 		    "BIOS microcode patch for AMD Athlon(tm) 64/Opteron(tm)"
1263 		    " processor\nerratum 131 was not detected; updating your"
1264 		    " system's BIOS to a version\ncontaining this"
1265 		    " microcode patch is HIGHLY recommended or erroneous"
1266 		    " system\noperation may occur.\n");
1267 	}
1268 #endif
1269 #if defined(OPTERON_WORKAROUND_6336786)
1270 	if (opteron_workaround_6336786)
1271 		workaround_applied(6336786);
1272 #endif
1273 #if defined(OPTERON_WORKAROUND_6323525)
1274 	if (opteron_workaround_6323525)
1275 		workaround_applied(6323525);
1276 #endif
1277 #if defined(OPTERON_ERRATUM_298)
1278 	if (opteron_erratum_298) {
1279 		cmn_err(CE_WARN,
1280 		    "BIOS microcode patch for AMD 64/Opteron(tm)"
1281 		    " processor\nerratum 298 was not detected; updating your"
1282 		    " system's BIOS to a version\ncontaining this"
1283 		    " microcode patch is HIGHLY recommended or erroneous"
1284 		    " system\noperation may occur.\n");
1285 	}
1286 #endif
1287 #if defined(OPTERON_ERRATUM_721)
1288 	if (opteron_erratum_721)
1289 		workaround_applied(721);
1290 #endif
1291 }
1292 
1293 /*
1294  * The procset_slave and procset_master are used to synchronize
1295  * between the control CPU and the target CPU when starting CPUs.
1296  */
1297 static cpuset_t procset_slave, procset_master;
1298 
1299 static void
1300 mp_startup_wait(cpuset_t *sp, processorid_t cpuid)
1301 {
1302 	cpuset_t tempset;
1303 
1304 	for (tempset = *sp; !CPU_IN_SET(tempset, cpuid);
1305 	    tempset = *(volatile cpuset_t *)sp) {
1306 		SMT_PAUSE();
1307 	}
1308 	CPUSET_ATOMIC_DEL(*(cpuset_t *)sp, cpuid);
1309 }
1310 
1311 static void
1312 mp_startup_signal(cpuset_t *sp, processorid_t cpuid)
1313 {
1314 	cpuset_t tempset;
1315 
1316 	CPUSET_ATOMIC_ADD(*(cpuset_t *)sp, cpuid);
1317 	for (tempset = *sp; CPU_IN_SET(tempset, cpuid);
1318 	    tempset = *(volatile cpuset_t *)sp) {
1319 		SMT_PAUSE();
1320 	}
1321 }
1322 
1323 int
1324 mp_start_cpu_common(cpu_t *cp, boolean_t boot)
1325 {
1326 	_NOTE(ARGUNUSED(boot));
1327 
1328 	void *ctx;
1329 	int delays;
1330 	int error = 0;
1331 	cpuset_t tempset;
1332 	processorid_t cpuid;
1333 #ifndef __xpv
1334 	extern void cpupm_init(cpu_t *);
1335 #endif
1336 
1337 	ASSERT(cp != NULL);
1338 	cpuid = cp->cpu_id;
1339 	ctx = mach_cpucontext_alloc(cp);
1340 	if (ctx == NULL) {
1341 		cmn_err(CE_WARN,
1342 		    "cpu%d: failed to allocate context", cp->cpu_id);
1343 		return (EAGAIN);
1344 	}
1345 	error = mach_cpu_start(cp, ctx);
1346 	if (error != 0) {
1347 		cmn_err(CE_WARN,
1348 		    "cpu%d: failed to start, error %d", cp->cpu_id, error);
1349 		mach_cpucontext_free(cp, ctx, error);
1350 		return (error);
1351 	}
1352 
1353 	for (delays = 0, tempset = procset_slave; !CPU_IN_SET(tempset, cpuid);
1354 	    delays++) {
1355 		if (delays == 500) {
1356 			/*
1357 			 * After five seconds, things are probably looking
1358 			 * a bit bleak - explain the hang.
1359 			 */
1360 			cmn_err(CE_NOTE, "cpu%d: started, "
1361 			    "but not running in the kernel yet", cpuid);
1362 		} else if (delays > 2000) {
1363 			/*
1364 			 * We waited at least 20 seconds, bail ..
1365 			 */
1366 			error = ETIMEDOUT;
1367 			cmn_err(CE_WARN, "cpu%d: timed out", cpuid);
1368 			mach_cpucontext_free(cp, ctx, error);
1369 			return (error);
1370 		}
1371 
1372 		/*
1373 		 * wait at least 10ms, then check again..
1374 		 */
1375 		delay(USEC_TO_TICK_ROUNDUP(10000));
1376 		tempset = *((volatile cpuset_t *)&procset_slave);
1377 	}
1378 	CPUSET_ATOMIC_DEL(procset_slave, cpuid);
1379 
1380 	mach_cpucontext_free(cp, ctx, 0);
1381 
1382 #ifndef __xpv
1383 	if (tsc_gethrtime_enable)
1384 		tsc_sync_master(cpuid);
1385 #endif
1386 
1387 	if (dtrace_cpu_init != NULL) {
1388 		(*dtrace_cpu_init)(cpuid);
1389 	}
1390 
1391 	/*
1392 	 * During CPU DR operations, the cpu_lock is held by current
1393 	 * (the control) thread. We can't release the cpu_lock here
1394 	 * because that will break the CPU DR logic.
1395 	 * On the other hand, CPUPM and processor group initialization
1396 	 * routines need to access the cpu_lock. So we invoke those
1397 	 * routines here on behalf of mp_startup_common().
1398 	 *
1399 	 * CPUPM and processor group initialization routines depend
1400 	 * on the cpuid probing results. Wait for mp_startup_common()
1401 	 * to signal that cpuid probing is done.
1402 	 */
1403 	mp_startup_wait(&procset_slave, cpuid);
1404 #ifndef __xpv
1405 	cpupm_init(cp);
1406 #endif
1407 	(void) pg_cpu_init(cp, B_FALSE);
1408 	cpu_set_state(cp);
1409 	mp_startup_signal(&procset_master, cpuid);
1410 
1411 	return (0);
1412 }
1413 
1414 /*
1415  * Start a single cpu, assuming that the kernel context is available
1416  * to successfully start another cpu.
1417  *
1418  * (For example, real mode code is mapped into the right place
1419  * in memory and is ready to be run.)
1420  */
1421 int
1422 start_cpu(processorid_t who)
1423 {
1424 	cpu_t *cp;
1425 	int error = 0;
1426 	cpuset_t tempset;
1427 
1428 	ASSERT(who != 0);
1429 
1430 	/*
1431 	 * Check if there's at least a Mbyte of kmem available
1432 	 * before attempting to start the cpu.
1433 	 */
1434 	if (kmem_avail() < 1024 * 1024) {
1435 		/*
1436 		 * Kick off a reap in case that helps us with
1437 		 * later attempts ..
1438 		 */
1439 		kmem_reap();
1440 		return (ENOMEM);
1441 	}
1442 
1443 	/*
1444 	 * First configure cpu.
1445 	 */
1446 	cp = mp_cpu_configure_common(who, B_TRUE);
1447 	ASSERT(cp != NULL);
1448 
1449 	/*
1450 	 * Then start cpu.
1451 	 */
1452 	error = mp_start_cpu_common(cp, B_TRUE);
1453 	if (error != 0) {
1454 		mp_cpu_unconfigure_common(cp, error);
1455 		return (error);
1456 	}
1457 
1458 	mutex_exit(&cpu_lock);
1459 	tempset = cpu_ready_set;
1460 	while (!CPU_IN_SET(tempset, who)) {
1461 		drv_usecwait(1);
1462 		tempset = *((volatile cpuset_t *)&cpu_ready_set);
1463 	}
1464 	mutex_enter(&cpu_lock);
1465 
1466 	return (0);
1467 }
1468 
1469 void
1470 start_other_cpus(int cprboot)
1471 {
1472 	_NOTE(ARGUNUSED(cprboot));
1473 
1474 	uint_t who;
1475 	uint_t bootcpuid = 0;
1476 
1477 	/*
1478 	 * Initialize our own cpu_info.
1479 	 */
1480 	init_cpu_info(CPU);
1481 
1482 	cmn_err(CE_CONT, "?cpu%d: %s\n", CPU->cpu_id, CPU->cpu_idstr);
1483 	cmn_err(CE_CONT, "?cpu%d: %s\n", CPU->cpu_id, CPU->cpu_brandstr);
1484 
1485 	/*
1486 	 * Initialize our syscall handlers
1487 	 */
1488 	init_cpu_syscall(CPU);
1489 
1490 	/*
1491 	 * Take the boot cpu out of the mp_cpus set because we know
1492 	 * it's already running.  Add it to the cpu_ready_set for
1493 	 * precisely the same reason.
1494 	 */
1495 	CPUSET_DEL(mp_cpus, bootcpuid);
1496 	CPUSET_ADD(cpu_ready_set, bootcpuid);
1497 
1498 	/*
1499 	 * skip the rest of this if
1500 	 * . only 1 cpu dectected and system isn't hotplug-capable
1501 	 * . not using MP
1502 	 */
1503 	if ((CPUSET_ISNULL(mp_cpus) && plat_dr_support_cpu() == 0) ||
1504 	    use_mp == 0) {
1505 		if (use_mp == 0)
1506 			cmn_err(CE_CONT, "?***** Not in MP mode\n");
1507 		goto done;
1508 	}
1509 
1510 	/*
1511 	 * perform such initialization as is needed
1512 	 * to be able to take CPUs on- and off-line.
1513 	 */
1514 	cpu_pause_init();
1515 
1516 	xc_init_cpu(CPU);		/* initialize processor crosscalls */
1517 
1518 	if (mach_cpucontext_init() != 0)
1519 		goto done;
1520 
1521 	flushes_require_xcalls = 1;
1522 
1523 	/*
1524 	 * We lock our affinity to the master CPU to ensure that all slave CPUs
1525 	 * do their TSC syncs with the same CPU.
1526 	 */
1527 	affinity_set(CPU_CURRENT);
1528 
1529 	for (who = 0; who < NCPU; who++) {
1530 		if (!CPU_IN_SET(mp_cpus, who))
1531 			continue;
1532 		ASSERT(who != bootcpuid);
1533 
1534 		mutex_enter(&cpu_lock);
1535 		if (start_cpu(who) != 0)
1536 			CPUSET_DEL(mp_cpus, who);
1537 		cpu_state_change_notify(who, CPU_SETUP);
1538 		mutex_exit(&cpu_lock);
1539 	}
1540 
1541 	/* Free the space allocated to hold the microcode file */
1542 	ucode_cleanup();
1543 
1544 	affinity_clear();
1545 
1546 	mach_cpucontext_fini();
1547 
1548 done:
1549 	if (get_hwenv() == HW_NATIVE)
1550 		workaround_errata_end();
1551 	cmi_post_mpstartup();
1552 
1553 	if (use_mp && ncpus != boot_max_ncpus) {
1554 		cmn_err(CE_NOTE,
1555 		    "System detected %d cpus, but "
1556 		    "only %d cpu(s) were enabled during boot.",
1557 		    boot_max_ncpus, ncpus);
1558 		cmn_err(CE_NOTE,
1559 		    "Use \"boot-ncpus\" parameter to enable more CPU(s). "
1560 		    "See eeprom(1M).");
1561 	}
1562 }
1563 
1564 int
1565 mp_cpu_configure(int cpuid)
1566 {
1567 	cpu_t *cp;
1568 
1569 	if (use_mp == 0 || plat_dr_support_cpu() == 0) {
1570 		return (ENOTSUP);
1571 	}
1572 
1573 	cp = cpu_get(cpuid);
1574 	if (cp != NULL) {
1575 		return (EALREADY);
1576 	}
1577 
1578 	/*
1579 	 * Check if there's at least a Mbyte of kmem available
1580 	 * before attempting to start the cpu.
1581 	 */
1582 	if (kmem_avail() < 1024 * 1024) {
1583 		/*
1584 		 * Kick off a reap in case that helps us with
1585 		 * later attempts ..
1586 		 */
1587 		kmem_reap();
1588 		return (ENOMEM);
1589 	}
1590 
1591 	cp = mp_cpu_configure_common(cpuid, B_FALSE);
1592 	ASSERT(cp != NULL && cpu_get(cpuid) == cp);
1593 
1594 	return (cp != NULL ? 0 : EAGAIN);
1595 }
1596 
1597 int
1598 mp_cpu_unconfigure(int cpuid)
1599 {
1600 	cpu_t *cp;
1601 
1602 	if (use_mp == 0 || plat_dr_support_cpu() == 0) {
1603 		return (ENOTSUP);
1604 	} else if (cpuid < 0 || cpuid >= max_ncpus) {
1605 		return (EINVAL);
1606 	}
1607 
1608 	cp = cpu_get(cpuid);
1609 	if (cp == NULL) {
1610 		return (ENODEV);
1611 	}
1612 	mp_cpu_unconfigure_common(cp, 0);
1613 
1614 	return (0);
1615 }
1616 
1617 /*
1618  * Startup function for 'other' CPUs (besides boot cpu).
1619  * Called from real_mode_start.
1620  *
1621  * WARNING: until CPU_READY is set, mp_startup_common and routines called by
1622  * mp_startup_common should not call routines (e.g. kmem_free) that could call
1623  * hat_unload which requires CPU_READY to be set.
1624  */
1625 static void
1626 mp_startup_common(boolean_t boot)
1627 {
1628 	cpu_t *cp = CPU;
1629 	uchar_t new_x86_featureset[BT_SIZEOFMAP(NUM_X86_FEATURES)];
1630 	extern void cpu_event_init_cpu(cpu_t *);
1631 
1632 	/*
1633 	 * We need to get TSC on this proc synced (i.e., any delta
1634 	 * from cpu0 accounted for) as soon as we can, because many
1635 	 * many things use gethrtime/pc_gethrestime, including
1636 	 * interrupts, cmn_err, etc.
1637 	 */
1638 
1639 	/* Let the control CPU continue into tsc_sync_master() */
1640 	mp_startup_signal(&procset_slave, cp->cpu_id);
1641 
1642 #ifndef __xpv
1643 	if (tsc_gethrtime_enable)
1644 		tsc_sync_slave();
1645 #endif
1646 
1647 	/*
1648 	 * Once this was done from assembly, but it's safer here; if
1649 	 * it blocks, we need to be able to swtch() to and from, and
1650 	 * since we get here by calling t_pc, we need to do that call
1651 	 * before swtch() overwrites it.
1652 	 */
1653 	(void) (*ap_mlsetup)();
1654 
1655 	bzero(new_x86_featureset, BT_SIZEOFMAP(NUM_X86_FEATURES));
1656 	cpuid_pass1(cp, new_x86_featureset);
1657 
1658 #ifndef __xpv
1659 	/*
1660 	 * Program this cpu's PAT
1661 	 */
1662 	if (is_x86_feature(x86_featureset, X86FSET_PAT))
1663 		pat_sync();
1664 #endif
1665 
1666 	/*
1667 	 * Set up TSC_AUX to contain the cpuid for this processor
1668 	 * for the rdtscp instruction.
1669 	 */
1670 	if (is_x86_feature(x86_featureset, X86FSET_TSCP))
1671 		(void) wrmsr(MSR_AMD_TSCAUX, cp->cpu_id);
1672 
1673 	/*
1674 	 * Initialize this CPU's syscall handlers
1675 	 */
1676 	init_cpu_syscall(cp);
1677 
1678 	/*
1679 	 * Enable interrupts with spl set to LOCK_LEVEL. LOCK_LEVEL is the
1680 	 * highest level at which a routine is permitted to block on
1681 	 * an adaptive mutex (allows for cpu poke interrupt in case
1682 	 * the cpu is blocked on a mutex and halts). Setting LOCK_LEVEL blocks
1683 	 * device interrupts that may end up in the hat layer issuing cross
1684 	 * calls before CPU_READY is set.
1685 	 */
1686 	splx(ipltospl(LOCK_LEVEL));
1687 	sti();
1688 
1689 	/*
1690 	 * Do a sanity check to make sure this new CPU is a sane thing
1691 	 * to add to the collection of processors running this system.
1692 	 *
1693 	 * XXX	Clearly this needs to get more sophisticated, if x86
1694 	 * systems start to get built out of heterogenous CPUs; as is
1695 	 * likely to happen once the number of processors in a configuration
1696 	 * gets large enough.
1697 	 */
1698 	if (compare_x86_featureset(x86_featureset, new_x86_featureset) ==
1699 	    B_FALSE) {
1700 		cmn_err(CE_CONT, "cpu%d: featureset\n", cp->cpu_id);
1701 		print_x86_featureset(new_x86_featureset);
1702 		cmn_err(CE_WARN, "cpu%d feature mismatch", cp->cpu_id);
1703 	}
1704 
1705 	/*
1706 	 * We do not support cpus with mixed monitor/mwait support if the
1707 	 * boot cpu supports monitor/mwait.
1708 	 */
1709 	if (is_x86_feature(x86_featureset, X86FSET_MWAIT) !=
1710 	    is_x86_feature(new_x86_featureset, X86FSET_MWAIT))
1711 		panic("unsupported mixed cpu monitor/mwait support detected");
1712 
1713 	/*
1714 	 * We could be more sophisticated here, and just mark the CPU
1715 	 * as "faulted" but at this point we'll opt for the easier
1716 	 * answer of dying horribly.  Provided the boot cpu is ok,
1717 	 * the system can be recovered by booting with use_mp set to zero.
1718 	 */
1719 	if (workaround_errata(cp) != 0)
1720 		panic("critical workaround(s) missing for cpu%d", cp->cpu_id);
1721 
1722 	/*
1723 	 * We can touch cpu_flags here without acquiring the cpu_lock here
1724 	 * because the cpu_lock is held by the control CPU which is running
1725 	 * mp_start_cpu_common().
1726 	 * Need to clear CPU_QUIESCED flag before calling any function which
1727 	 * may cause thread context switching, such as kmem_alloc() etc.
1728 	 * The idle thread checks for CPU_QUIESCED flag and loops for ever if
1729 	 * it's set. So the startup thread may have no chance to switch back
1730 	 * again if it's switched away with CPU_QUIESCED set.
1731 	 */
1732 	cp->cpu_flags &= ~(CPU_POWEROFF | CPU_QUIESCED);
1733 
1734 	/*
1735 	 * Setup this processor for XSAVE.
1736 	 */
1737 	if (fp_save_mech == FP_XSAVE) {
1738 		xsave_setup_msr(cp);
1739 	}
1740 
1741 	cpuid_pass2(cp);
1742 	cpuid_pass3(cp);
1743 	cpuid_pass4(cp, NULL);
1744 
1745 	/*
1746 	 * Correct cpu_idstr and cpu_brandstr on target CPU after
1747 	 * cpuid_pass1() is done.
1748 	 */
1749 	(void) cpuid_getidstr(cp, cp->cpu_idstr, CPU_IDSTRLEN);
1750 	(void) cpuid_getbrandstr(cp, cp->cpu_brandstr, CPU_IDSTRLEN);
1751 
1752 	cp->cpu_flags |= CPU_RUNNING | CPU_READY | CPU_EXISTS;
1753 
1754 	post_startup_cpu_fixups();
1755 
1756 	cpu_event_init_cpu(cp);
1757 
1758 	/*
1759 	 * Enable preemption here so that contention for any locks acquired
1760 	 * later in mp_startup_common may be preempted if the thread owning
1761 	 * those locks is continuously executing on other CPUs (for example,
1762 	 * this CPU must be preemptible to allow other CPUs to pause it during
1763 	 * their startup phases).  It's safe to enable preemption here because
1764 	 * the CPU state is pretty-much fully constructed.
1765 	 */
1766 	curthread->t_preempt = 0;
1767 
1768 	/* The base spl should still be at LOCK LEVEL here */
1769 	ASSERT(cp->cpu_base_spl == ipltospl(LOCK_LEVEL));
1770 	set_base_spl();		/* Restore the spl to its proper value */
1771 
1772 	pghw_physid_create(cp);
1773 	/*
1774 	 * Delegate initialization tasks, which need to access the cpu_lock,
1775 	 * to mp_start_cpu_common() because we can't acquire the cpu_lock here
1776 	 * during CPU DR operations.
1777 	 */
1778 	mp_startup_signal(&procset_slave, cp->cpu_id);
1779 	mp_startup_wait(&procset_master, cp->cpu_id);
1780 	pg_cmt_cpu_startup(cp);
1781 
1782 	if (boot) {
1783 		mutex_enter(&cpu_lock);
1784 		cp->cpu_flags &= ~CPU_OFFLINE;
1785 		cpu_enable_intr(cp);
1786 		cpu_add_active(cp);
1787 		mutex_exit(&cpu_lock);
1788 	}
1789 
1790 	/* Enable interrupts */
1791 	(void) spl0();
1792 
1793 	/*
1794 	 * Fill out cpu_ucode_info.  Update microcode if necessary.
1795 	 */
1796 	ucode_check(cp);
1797 
1798 #ifndef __xpv
1799 	{
1800 		/*
1801 		 * Set up the CPU module for this CPU.  This can't be done
1802 		 * before this CPU is made CPU_READY, because we may (in
1803 		 * heterogeneous systems) need to go load another CPU module.
1804 		 * The act of attempting to load a module may trigger a
1805 		 * cross-call, which will ASSERT unless this cpu is CPU_READY.
1806 		 */
1807 		cmi_hdl_t hdl;
1808 
1809 		if ((hdl = cmi_init(CMI_HDL_NATIVE, cmi_ntv_hwchipid(CPU),
1810 		    cmi_ntv_hwcoreid(CPU), cmi_ntv_hwstrandid(CPU))) != NULL) {
1811 			if (is_x86_feature(x86_featureset, X86FSET_MCA))
1812 				cmi_mca_init(hdl);
1813 			cp->cpu_m.mcpu_cmi_hdl = hdl;
1814 		}
1815 	}
1816 #endif /* __xpv */
1817 
1818 	if (boothowto & RB_DEBUG)
1819 		kdi_cpu_init();
1820 
1821 	/*
1822 	 * Setting the bit in cpu_ready_set must be the last operation in
1823 	 * processor initialization; the boot CPU will continue to boot once
1824 	 * it sees this bit set for all active CPUs.
1825 	 */
1826 	CPUSET_ATOMIC_ADD(cpu_ready_set, cp->cpu_id);
1827 
1828 	(void) mach_cpu_create_device_node(cp, NULL);
1829 
1830 	cmn_err(CE_CONT, "?cpu%d: %s\n", cp->cpu_id, cp->cpu_idstr);
1831 	cmn_err(CE_CONT, "?cpu%d: %s\n", cp->cpu_id, cp->cpu_brandstr);
1832 	cmn_err(CE_CONT, "?cpu%d initialization complete - online\n",
1833 	    cp->cpu_id);
1834 
1835 	/*
1836 	 * Now we are done with the startup thread, so free it up.
1837 	 */
1838 	thread_exit();
1839 	panic("mp_startup: cannot return");
1840 	/*NOTREACHED*/
1841 }
1842 
1843 /*
1844  * Startup function for 'other' CPUs at boot time (besides boot cpu).
1845  */
1846 static void
1847 mp_startup_boot(void)
1848 {
1849 	mp_startup_common(B_TRUE);
1850 }
1851 
1852 /*
1853  * Startup function for hotplug CPUs at runtime.
1854  */
1855 void
1856 mp_startup_hotplug(void)
1857 {
1858 	mp_startup_common(B_FALSE);
1859 }
1860 
1861 /*
1862  * Start CPU on user request.
1863  */
1864 /* ARGSUSED */
1865 int
1866 mp_cpu_start(struct cpu *cp)
1867 {
1868 	ASSERT(MUTEX_HELD(&cpu_lock));
1869 	return (0);
1870 }
1871 
1872 /*
1873  * Stop CPU on user request.
1874  */
1875 int
1876 mp_cpu_stop(struct cpu *cp)
1877 {
1878 	extern int cbe_psm_timer_mode;
1879 	ASSERT(MUTEX_HELD(&cpu_lock));
1880 
1881 #ifdef __xpv
1882 	/*
1883 	 * We can't offline vcpu0.
1884 	 */
1885 	if (cp->cpu_id == 0)
1886 		return (EBUSY);
1887 #endif
1888 
1889 	/*
1890 	 * If TIMER_PERIODIC mode is used, CPU0 is the one running it;
1891 	 * can't stop it.  (This is true only for machines with no TSC.)
1892 	 */
1893 
1894 	if ((cbe_psm_timer_mode == TIMER_PERIODIC) && (cp->cpu_id == 0))
1895 		return (EBUSY);
1896 
1897 	return (0);
1898 }
1899 
1900 /*
1901  * Take the specified CPU out of participation in interrupts.
1902  */
1903 int
1904 cpu_disable_intr(struct cpu *cp)
1905 {
1906 	if (psm_disable_intr(cp->cpu_id) != DDI_SUCCESS)
1907 		return (EBUSY);
1908 
1909 	cp->cpu_flags &= ~CPU_ENABLE;
1910 	return (0);
1911 }
1912 
1913 /*
1914  * Allow the specified CPU to participate in interrupts.
1915  */
1916 void
1917 cpu_enable_intr(struct cpu *cp)
1918 {
1919 	ASSERT(MUTEX_HELD(&cpu_lock));
1920 	cp->cpu_flags |= CPU_ENABLE;
1921 	psm_enable_intr(cp->cpu_id);
1922 }
1923 
1924 void
1925 mp_cpu_faulted_enter(struct cpu *cp)
1926 {
1927 #ifdef __xpv
1928 	_NOTE(ARGUNUSED(cp));
1929 #else
1930 	cmi_hdl_t hdl = cp->cpu_m.mcpu_cmi_hdl;
1931 
1932 	if (hdl != NULL) {
1933 		cmi_hdl_hold(hdl);
1934 	} else {
1935 		hdl = cmi_hdl_lookup(CMI_HDL_NATIVE, cmi_ntv_hwchipid(cp),
1936 		    cmi_ntv_hwcoreid(cp), cmi_ntv_hwstrandid(cp));
1937 	}
1938 	if (hdl != NULL) {
1939 		cmi_faulted_enter(hdl);
1940 		cmi_hdl_rele(hdl);
1941 	}
1942 #endif
1943 }
1944 
1945 void
1946 mp_cpu_faulted_exit(struct cpu *cp)
1947 {
1948 #ifdef __xpv
1949 	_NOTE(ARGUNUSED(cp));
1950 #else
1951 	cmi_hdl_t hdl = cp->cpu_m.mcpu_cmi_hdl;
1952 
1953 	if (hdl != NULL) {
1954 		cmi_hdl_hold(hdl);
1955 	} else {
1956 		hdl = cmi_hdl_lookup(CMI_HDL_NATIVE, cmi_ntv_hwchipid(cp),
1957 		    cmi_ntv_hwcoreid(cp), cmi_ntv_hwstrandid(cp));
1958 	}
1959 	if (hdl != NULL) {
1960 		cmi_faulted_exit(hdl);
1961 		cmi_hdl_rele(hdl);
1962 	}
1963 #endif
1964 }
1965 
1966 /*
1967  * The following two routines are used as context operators on threads belonging
1968  * to processes with a private LDT (see sysi86).  Due to the rarity of such
1969  * processes, these routines are currently written for best code readability and
1970  * organization rather than speed.  We could avoid checking x86_featureset at
1971  * every context switch by installing different context ops, depending on
1972  * x86_featureset, at LDT creation time -- one for each combination of fast
1973  * syscall features.
1974  */
1975 
1976 /*ARGSUSED*/
1977 void
1978 cpu_fast_syscall_disable(void *arg)
1979 {
1980 	if (is_x86_feature(x86_featureset, X86FSET_MSR) &&
1981 	    is_x86_feature(x86_featureset, X86FSET_SEP))
1982 		cpu_sep_disable();
1983 	if (is_x86_feature(x86_featureset, X86FSET_MSR) &&
1984 	    is_x86_feature(x86_featureset, X86FSET_ASYSC))
1985 		cpu_asysc_disable();
1986 }
1987 
1988 /*ARGSUSED*/
1989 void
1990 cpu_fast_syscall_enable(void *arg)
1991 {
1992 	if (is_x86_feature(x86_featureset, X86FSET_MSR) &&
1993 	    is_x86_feature(x86_featureset, X86FSET_SEP))
1994 		cpu_sep_enable();
1995 	if (is_x86_feature(x86_featureset, X86FSET_MSR) &&
1996 	    is_x86_feature(x86_featureset, X86FSET_ASYSC))
1997 		cpu_asysc_enable();
1998 }
1999 
2000 static void
2001 cpu_sep_enable(void)
2002 {
2003 	ASSERT(is_x86_feature(x86_featureset, X86FSET_SEP));
2004 	ASSERT(curthread->t_preempt || getpil() >= LOCK_LEVEL);
2005 
2006 	wrmsr(MSR_INTC_SEP_CS, (uint64_t)(uintptr_t)KCS_SEL);
2007 }
2008 
2009 static void
2010 cpu_sep_disable(void)
2011 {
2012 	ASSERT(is_x86_feature(x86_featureset, X86FSET_SEP));
2013 	ASSERT(curthread->t_preempt || getpil() >= LOCK_LEVEL);
2014 
2015 	/*
2016 	 * Setting the SYSENTER_CS_MSR register to 0 causes software executing
2017 	 * the sysenter or sysexit instruction to trigger a #gp fault.
2018 	 */
2019 	wrmsr(MSR_INTC_SEP_CS, 0);
2020 }
2021 
2022 static void
2023 cpu_asysc_enable(void)
2024 {
2025 	ASSERT(is_x86_feature(x86_featureset, X86FSET_ASYSC));
2026 	ASSERT(curthread->t_preempt || getpil() >= LOCK_LEVEL);
2027 
2028 	wrmsr(MSR_AMD_EFER, rdmsr(MSR_AMD_EFER) |
2029 	    (uint64_t)(uintptr_t)AMD_EFER_SCE);
2030 }
2031 
2032 static void
2033 cpu_asysc_disable(void)
2034 {
2035 	ASSERT(is_x86_feature(x86_featureset, X86FSET_ASYSC));
2036 	ASSERT(curthread->t_preempt || getpil() >= LOCK_LEVEL);
2037 
2038 	/*
2039 	 * Turn off the SCE (syscall enable) bit in the EFER register. Software
2040 	 * executing syscall or sysret with this bit off will incur a #ud trap.
2041 	 */
2042 	wrmsr(MSR_AMD_EFER, rdmsr(MSR_AMD_EFER) &
2043 	    ~((uint64_t)(uintptr_t)AMD_EFER_SCE));
2044 }
2045