xref: /titanic_52/usr/src/uts/i86pc/os/mp_startup.c (revision fb3fb4f3d76d55b64440afd0af72775dfad3bd1d)
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, Version 1.0 only
6  * (the "License").  You may not use this file except in compliance
7  * with the License.
8  *
9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10  * or http://www.opensolaris.org/os/licensing.
11  * See the License for the specific language governing permissions
12  * and limitations under the License.
13  *
14  * When distributing Covered Code, include this CDDL HEADER in each
15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16  * If applicable, add the following below this CDDL HEADER, with the
17  * fields enclosed by brackets "[]" replaced with your own identifying
18  * information: Portions Copyright [yyyy] [name of copyright owner]
19  *
20  * CDDL HEADER END
21  */
22 /*
23  * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 
27 #pragma ident	"%Z%%M%	%I%	%E% SMI"
28 
29 #include <sys/types.h>
30 #include <sys/thread.h>
31 #include <sys/cpuvar.h>
32 #include <sys/t_lock.h>
33 #include <sys/param.h>
34 #include <sys/proc.h>
35 #include <sys/disp.h>
36 #include <sys/mmu.h>
37 #include <sys/class.h>
38 #include <sys/cmn_err.h>
39 #include <sys/debug.h>
40 #include <sys/asm_linkage.h>
41 #include <sys/x_call.h>
42 #include <sys/systm.h>
43 #include <sys/var.h>
44 #include <sys/vtrace.h>
45 #include <vm/hat.h>
46 #include <sys/mmu.h>
47 #include <vm/as.h>
48 #include <vm/seg_kmem.h>
49 #include <sys/segments.h>
50 #include <sys/kmem.h>
51 #include <sys/stack.h>
52 #include <sys/smp_impldefs.h>
53 #include <sys/x86_archext.h>
54 #include <sys/machsystm.h>
55 #include <sys/traptrace.h>
56 #include <sys/clock.h>
57 #include <sys/cpc_impl.h>
58 #include <sys/chip.h>
59 #include <sys/dtrace.h>
60 #include <sys/archsystm.h>
61 #include <sys/fp.h>
62 #include <sys/reboot.h>
63 #include <sys/kdi.h>
64 #include <vm/hat_i86.h>
65 #include <sys/memnode.h>
66 #include <sys/pci_cfgspace.h>
67 #include <sys/cpu_module.h>
68 
69 struct cpu	cpus[1];			/* CPU data */
70 struct cpu	*cpu[NCPU] = {&cpus[0]};	/* pointers to all CPUs */
71 cpu_core_t	cpu_core[NCPU];			/* cpu_core structures */
72 
73 /*
74  * Useful for disabling MP bring-up for an MP capable kernel
75  * (a kernel that was built with MP defined)
76  */
77 int use_mp = 1;
78 
79 int mp_cpus = 0x1;	/* to be set by platform specific module	*/
80 
81 /*
82  * This variable is used by the hat layer to decide whether or not
83  * critical sections are needed to prevent race conditions.  For sun4m,
84  * this variable is set once enough MP initialization has been done in
85  * order to allow cross calls.
86  */
87 int flushes_require_xcalls = 0;
88 ulong_t	cpu_ready_set = 1;
89 
90 extern	void	real_mode_start(void);
91 extern	void	real_mode_end(void);
92 static 	void	mp_startup(void);
93 
94 static void cpu_sep_enable(void);
95 static void cpu_sep_disable(void);
96 static void cpu_asysc_enable(void);
97 static void cpu_asysc_disable(void);
98 
99 extern int tsc_gethrtime_enable;
100 
101 /*
102  * Init CPU info - get CPU type info for processor_info system call.
103  */
104 void
105 init_cpu_info(struct cpu *cp)
106 {
107 	processor_info_t *pi = &cp->cpu_type_info;
108 	char buf[CPU_IDSTRLEN];
109 
110 	/*
111 	 * Get clock-frequency property for the CPU.
112 	 */
113 	pi->pi_clock = cpu_freq;
114 
115 	(void) strcpy(pi->pi_processor_type, "i386");
116 	if (fpu_exists)
117 		(void) strcpy(pi->pi_fputypes, "i387 compatible");
118 
119 	(void) cpuid_getidstr(cp, buf, sizeof (buf));
120 
121 	cp->cpu_idstr = kmem_alloc(strlen(buf) + 1, KM_SLEEP);
122 	(void) strcpy(cp->cpu_idstr, buf);
123 
124 	cmn_err(CE_CONT, "?cpu%d: %s\n", cp->cpu_id, cp->cpu_idstr);
125 
126 	(void) cpuid_getbrandstr(cp, buf, sizeof (buf));
127 	cp->cpu_brandstr = kmem_alloc(strlen(buf) + 1, KM_SLEEP);
128 	(void) strcpy(cp->cpu_brandstr, buf);
129 
130 	cmn_err(CE_CONT, "?cpu%d: %s\n", cp->cpu_id, cp->cpu_brandstr);
131 }
132 
133 /*
134  * Configure syscall support on this CPU.
135  */
136 /*ARGSUSED*/
137 static void
138 init_cpu_syscall(struct cpu *cp)
139 {
140 	kpreempt_disable();
141 
142 #if defined(__amd64)
143 	if (x86_feature & X86_ASYSC) {
144 
145 #if !defined(__lint)
146 		/*
147 		 * The syscall instruction imposes a certain ordering on
148 		 * segment selectors, so we double-check that ordering
149 		 * here.
150 		 */
151 		ASSERT(KDS_SEL == KCS_SEL + 8);
152 		ASSERT(UDS_SEL == U32CS_SEL + 8);
153 		ASSERT(UCS_SEL == U32CS_SEL + 16);
154 #endif
155 		/*
156 		 * Turn syscall/sysret extensions on.
157 		 */
158 		cpu_asysc_enable();
159 
160 		/*
161 		 * Program the magic registers ..
162 		 */
163 		wrmsr(MSR_AMD_STAR, ((uint64_t)(U32CS_SEL << 16 | KCS_SEL)) <<
164 		    32);
165 		wrmsr(MSR_AMD_LSTAR, (uint64_t)(uintptr_t)sys_syscall);
166 		wrmsr(MSR_AMD_CSTAR, (uint64_t)(uintptr_t)sys_syscall32);
167 
168 		/*
169 		 * This list of flags is masked off the incoming
170 		 * %rfl when we enter the kernel.
171 		 */
172 		wrmsr(MSR_AMD_SFMASK, (uint64_t)(uintptr_t)(PS_IE | PS_T));
173 	}
174 #endif
175 
176 	/*
177 	 * On 32-bit kernels, we use sysenter/sysexit because it's too
178 	 * hard to use syscall/sysret, and it is more portable anyway.
179 	 *
180 	 * On 64-bit kernels on Nocona machines, the 32-bit syscall
181 	 * variant isn't available to 32-bit applications, but sysenter is.
182 	 */
183 	if (x86_feature & X86_SEP) {
184 
185 #if !defined(__lint)
186 		/*
187 		 * The sysenter instruction imposes a certain ordering on
188 		 * segment selectors, so we double-check that ordering
189 		 * here. See "sysenter" in Intel document 245471-012, "IA-32
190 		 * Intel Architecture Software Developer's Manual Volume 2:
191 		 * Instruction Set Reference"
192 		 */
193 		ASSERT(KDS_SEL == KCS_SEL + 8);
194 
195 		ASSERT32(UCS_SEL == ((KCS_SEL + 16) | 3));
196 		ASSERT32(UDS_SEL == UCS_SEL + 8);
197 
198 		ASSERT64(U32CS_SEL == ((KCS_SEL + 16) | 3));
199 		ASSERT64(UDS_SEL == U32CS_SEL + 8);
200 #endif
201 
202 		cpu_sep_enable();
203 
204 		/*
205 		 * resume() sets this value to the base of the threads stack
206 		 * via a context handler.
207 		 */
208 		wrmsr(MSR_INTC_SEP_ESP, 0ULL);
209 		wrmsr(MSR_INTC_SEP_EIP, (uint64_t)(uintptr_t)sys_sysenter);
210 	}
211 
212 	kpreempt_enable();
213 }
214 
215 /*
216  * Multiprocessor initialization.
217  *
218  * Allocate and initialize the cpu structure, TRAPTRACE buffer, and the
219  * startup and idle threads for the specified CPU.
220  */
221 static void
222 mp_startup_init(int cpun)
223 {
224 #if defined(__amd64)
225 extern void *long_mode_64(void);
226 #endif	/* __amd64 */
227 
228 	struct cpu *cp;
229 	struct tss *ntss;
230 	kthread_id_t tp;
231 	caddr_t	sp;
232 	int size;
233 	proc_t *procp;
234 	extern void idle();
235 	extern void init_intr_threads(struct cpu *);
236 
237 	struct cpu_tables *tablesp;
238 	rm_platter_t *real_mode_platter = (rm_platter_t *)rm_platter_va;
239 
240 #ifdef TRAPTRACE
241 	trap_trace_ctl_t *ttc = &trap_trace_ctl[cpun];
242 #endif
243 
244 	ASSERT(cpun < NCPU && cpu[cpun] == NULL);
245 
246 	if ((cp = kmem_zalloc(sizeof (*cp), KM_NOSLEEP)) == NULL) {
247 		panic("mp_startup_init: cpu%d: "
248 		    "no memory for cpu structure", cpun);
249 		/*NOTREACHED*/
250 	}
251 	procp = curthread->t_procp;
252 
253 	mutex_enter(&cpu_lock);
254 	/*
255 	 * Initialize the dispatcher first.
256 	 */
257 	disp_cpu_init(cp);
258 	mutex_exit(&cpu_lock);
259 
260 	cpu_vm_data_init(cp);
261 
262 	/*
263 	 * Allocate and initialize the startup thread for this CPU.
264 	 * Interrupt and process switch stacks get allocated later
265 	 * when the CPU starts running.
266 	 */
267 	tp = thread_create(NULL, 0, NULL, NULL, 0, procp,
268 	    TS_STOPPED, maxclsyspri);
269 
270 	/*
271 	 * Set state to TS_ONPROC since this thread will start running
272 	 * as soon as the CPU comes online.
273 	 *
274 	 * All the other fields of the thread structure are setup by
275 	 * thread_create().
276 	 */
277 	THREAD_ONPROC(tp, cp);
278 	tp->t_preempt = 1;
279 	tp->t_bound_cpu = cp;
280 	tp->t_affinitycnt = 1;
281 	tp->t_cpu = cp;
282 	tp->t_disp_queue = cp->cpu_disp;
283 
284 	/*
285 	 * Setup thread to start in mp_startup.
286 	 */
287 	sp = tp->t_stk;
288 	tp->t_pc = (uintptr_t)mp_startup;
289 	tp->t_sp = (uintptr_t)(sp - MINFRAME);
290 
291 	cp->cpu_id = cpun;
292 	cp->cpu_self = cp;
293 	cp->cpu_mask = 1 << cpun;
294 	cp->cpu_thread = tp;
295 	cp->cpu_lwp = NULL;
296 	cp->cpu_dispthread = tp;
297 	cp->cpu_dispatch_pri = DISP_PRIO(tp);
298 
299 	/*
300 	 * Now, initialize per-CPU idle thread for this CPU.
301 	 */
302 	tp = thread_create(NULL, PAGESIZE, idle, NULL, 0, procp, TS_ONPROC, -1);
303 
304 	cp->cpu_idle_thread = tp;
305 
306 	tp->t_preempt = 1;
307 	tp->t_bound_cpu = cp;
308 	tp->t_affinitycnt = 1;
309 	tp->t_cpu = cp;
310 	tp->t_disp_queue = cp->cpu_disp;
311 
312 	/*
313 	 * Bootstrap the CPU for CMT aware scheduling
314 	 * The rest of the initialization will happen from
315 	 * mp_startup()
316 	 */
317 	chip_bootstrap_cpu(cp);
318 
319 	/*
320 	 * Perform CPC intialization on the new CPU.
321 	 */
322 	kcpc_hw_init(cp);
323 
324 	/*
325 	 * Allocate virtual addresses for cpu_caddr1 and cpu_caddr2
326 	 * for each CPU.
327 	 */
328 
329 	setup_vaddr_for_ppcopy(cp);
330 
331 	/*
332 	 * Allocate space for page directory, stack, tss, gdt and idt.
333 	 * This assumes that kmem_alloc will return memory which is aligned
334 	 * to the next higher power of 2 or a page(if size > MAXABIG)
335 	 * If this assumption goes wrong at any time due to change in
336 	 * kmem alloc, things may not work as the page directory has to be
337 	 * page aligned
338 	 */
339 	if ((tablesp = kmem_zalloc(sizeof (*tablesp), KM_NOSLEEP)) == NULL)
340 		panic("mp_startup_init: cpu%d cannot allocate tables", cpun);
341 
342 	if ((uintptr_t)tablesp & ~MMU_STD_PAGEMASK) {
343 		kmem_free(tablesp, sizeof (struct cpu_tables));
344 		size = sizeof (struct cpu_tables) + MMU_STD_PAGESIZE;
345 		tablesp = kmem_zalloc(size, KM_NOSLEEP);
346 		tablesp = (struct cpu_tables *)
347 		    (((uintptr_t)tablesp + MMU_STD_PAGESIZE) &
348 		    MMU_STD_PAGEMASK);
349 	}
350 
351 	ntss = cp->cpu_tss = &tablesp->ct_tss;
352 	cp->cpu_gdt = tablesp->ct_gdt;
353 	bcopy(CPU->cpu_gdt, cp->cpu_gdt, NGDT * (sizeof (user_desc_t)));
354 
355 #if defined(__amd64)
356 
357 	/*
358 	 * #DF (double fault).
359 	 */
360 	ntss->tss_ist1 =
361 	    (uint64_t)&tablesp->ct_stack[sizeof (tablesp->ct_stack)];
362 
363 #elif defined(__i386)
364 
365 	ntss->tss_esp0 = ntss->tss_esp1 = ntss->tss_esp2 = ntss->tss_esp =
366 	    (uint32_t)&tablesp->ct_stack[sizeof (tablesp->ct_stack)];
367 
368 	ntss->tss_ss0 = ntss->tss_ss1 = ntss->tss_ss2 = ntss->tss_ss = KDS_SEL;
369 
370 	ntss->tss_eip = (uint32_t)mp_startup;
371 
372 	ntss->tss_cs = KCS_SEL;
373 	ntss->tss_fs = KFS_SEL;
374 	ntss->tss_gs = KGS_SEL;
375 
376 	/*
377 	 * setup kernel %gs.
378 	 */
379 	set_usegd(&cp->cpu_gdt[GDT_GS], cp, sizeof (struct cpu) -1, SDT_MEMRWA,
380 	    SEL_KPL, 0, 1);
381 
382 #endif	/* __i386 */
383 
384 	/*
385 	 * Set I/O bit map offset equal to size of TSS segment limit
386 	 * for no I/O permission map. This will cause all user I/O
387 	 * instructions to generate #gp fault.
388 	 */
389 	ntss->tss_bitmapbase = sizeof (*ntss);
390 
391 	/*
392 	 * setup kernel tss.
393 	 */
394 	set_syssegd((system_desc_t *)&cp->cpu_gdt[GDT_KTSS], cp->cpu_tss,
395 	    sizeof (*cp->cpu_tss) -1, SDT_SYSTSS, SEL_KPL);
396 
397 	/*
398 	 * If we have more than one node, each cpu gets a copy of IDT
399 	 * local to its node. If this is a Pentium box, we use cpu 0's
400 	 * IDT. cpu 0's IDT has been made read-only to workaround the
401 	 * cmpxchgl register bug
402 	 */
403 	cp->cpu_idt = CPU->cpu_idt;
404 	if (system_hardware.hd_nodes && x86_type != X86_TYPE_P5) {
405 		cp->cpu_idt = kmem_alloc(sizeof (idt0), KM_SLEEP);
406 		bcopy(idt0, cp->cpu_idt, sizeof (idt0));
407 	}
408 
409 	/*
410 	 * Get interrupt priority data from cpu 0
411 	 */
412 	cp->cpu_pri_data = CPU->cpu_pri_data;
413 
414 	hat_cpu_online(cp);
415 
416 	/* Should remove all entries for the current process/thread here */
417 
418 	/*
419 	 * Fill up the real mode platter to make it easy for real mode code to
420 	 * kick it off. This area should really be one passed by boot to kernel
421 	 * and guaranteed to be below 1MB and aligned to 16 bytes. Should also
422 	 * have identical physical and virtual address in paged mode.
423 	 */
424 	real_mode_platter->rm_idt_base = cp->cpu_idt;
425 	real_mode_platter->rm_idt_lim = sizeof (idt0) - 1;
426 	real_mode_platter->rm_gdt_base = cp->cpu_gdt;
427 	real_mode_platter->rm_gdt_lim = sizeof (gdt0) -1;
428 	real_mode_platter->rm_pdbr = getcr3();
429 	real_mode_platter->rm_cpu = cpun;
430 	real_mode_platter->rm_x86feature = x86_feature;
431 	real_mode_platter->rm_cr4 = cr4_value;
432 
433 #if defined(__amd64)
434 	if (getcr3() > 0xffffffffUL)
435 		panic("Cannot initialize CPUs; kernel's 64-bit page tables\n"
436 			"located above 4G in physical memory (@ 0x%llx).",
437 			(unsigned long long)getcr3());
438 
439 	/*
440 	 * Setup pseudo-descriptors for temporary GDT and IDT for use ONLY
441 	 * by code in real_mode_start():
442 	 *
443 	 * GDT[0]:  NULL selector
444 	 * GDT[1]:  64-bit CS: Long = 1, Present = 1, bits 12, 11 = 1
445 	 *
446 	 * Clear the IDT as interrupts will be off and a limit of 0 will cause
447 	 * the CPU to triple fault and reset on an NMI, seemingly as reasonable
448 	 * a course of action as any other, though it may cause the entire
449 	 * platform to reset in some cases...
450 	 */
451 	real_mode_platter->rm_temp_gdt[0] = 0ULL;
452 	real_mode_platter->rm_temp_gdt[TEMPGDT_KCODE64] = 0x20980000000000ULL;
453 
454 	real_mode_platter->rm_temp_gdt_lim = (ushort_t)
455 	    (sizeof (real_mode_platter->rm_temp_gdt) - 1);
456 	real_mode_platter->rm_temp_gdt_base = rm_platter_pa +
457 	    (uint32_t)(&((rm_platter_t *)0)->rm_temp_gdt);
458 
459 	real_mode_platter->rm_temp_idt_lim = 0;
460 	real_mode_platter->rm_temp_idt_base = 0;
461 
462 	/*
463 	 * Since the CPU needs to jump to protected mode using an identity
464 	 * mapped address, we need to calculate it here.
465 	 */
466 	real_mode_platter->rm_longmode64_addr = rm_platter_pa +
467 	    ((uint32_t)long_mode_64 - (uint32_t)real_mode_start);
468 #endif	/* __amd64 */
469 
470 #ifdef TRAPTRACE
471 	/*
472 	 * If this is a TRAPTRACE kernel, allocate TRAPTRACE buffers for this
473 	 * CPU.
474 	 */
475 	ttc->ttc_first = (uintptr_t)kmem_zalloc(trap_trace_bufsize, KM_SLEEP);
476 	ttc->ttc_next = ttc->ttc_first;
477 	ttc->ttc_limit = ttc->ttc_first + trap_trace_bufsize;
478 #endif
479 
480 	/*
481 	 * Record that we have another CPU.
482 	 */
483 	mutex_enter(&cpu_lock);
484 	/*
485 	 * Initialize the interrupt threads for this CPU
486 	 */
487 	init_intr_threads(cp);
488 	/*
489 	 * Add CPU to list of available CPUs.  It'll be on the active list
490 	 * after mp_startup().
491 	 */
492 	cpu_add_unit(cp);
493 	mutex_exit(&cpu_lock);
494 }
495 
496 /*
497  * Apply workarounds for known errata, and warn about those that are absent.
498  *
499  * System vendors occasionally create configurations which contain different
500  * revisions of the CPUs that are almost but not exactly the same.  At the
501  * time of writing, this meant that their clock rates were the same, their
502  * feature sets were the same, but the required workaround were -not-
503  * necessarily the same.  So, this routine is invoked on -every- CPU soon
504  * after starting to make sure that the resulting system contains the most
505  * pessimal set of workarounds needed to cope with *any* of the CPUs in the
506  * system.
507  *
508  * workaround_errata is invoked early in mlsetup() for CPU 0, and in
509  * mp_startup() for all slave CPUs. Slaves process workaround_errata prior
510  * to acknowledging their readiness to the master, so this routine will
511  * never be executed by multiple CPUs in parallel, thus making updates to
512  * global data safe.
513  *
514  * These workarounds are based on Rev 3.57 of the Revision Guide for
515  * AMD Athlon(tm) 64 and AMD Opteron(tm) Processors, August 2005.
516  */
517 
518 #if defined(OPTERON_ERRATUM_91)
519 int opteron_erratum_91;		/* if non-zero -> at least one cpu has it */
520 #endif
521 
522 #if defined(OPTERON_ERRATUM_93)
523 int opteron_erratum_93;		/* if non-zero -> at least one cpu has it */
524 #endif
525 
526 #if defined(OPTERON_ERRATUM_100)
527 int opteron_erratum_100;	/* if non-zero -> at least one cpu has it */
528 #endif
529 
530 #if defined(OPTERON_ERRATUM_109)
531 int opteron_erratum_109;	/* if non-zero -> at least one cpu has it */
532 #endif
533 
534 #if defined(OPTERON_ERRATUM_121)
535 int opteron_erratum_121;	/* if non-zero -> at least one cpu has it */
536 #endif
537 
538 #if defined(OPTERON_ERRATUM_122)
539 int opteron_erratum_122;	/* if non-zero -> at least one cpu has it */
540 #endif
541 
542 #if defined(OPTERON_ERRATUM_123)
543 int opteron_erratum_123;	/* if non-zero -> at least one cpu has it */
544 #endif
545 
546 #if defined(OPTERON_ERRATUM_131)
547 int opteron_erratum_131;	/* if non-zero -> at least one cpu has it */
548 #endif
549 
550 #if defined(OPTERON_WORKAROUND_6336786)
551 int opteron_workaround_6336786;	/* non-zero -> WA relevant and applied */
552 int opteron_workaround_6336786_UP = 0;	/* Not needed for UP */
553 #endif
554 
555 #define	WARNING(cpu, n)						\
556 	cmn_err(CE_WARN, "cpu%d: no workaround for erratum %d",	\
557 	    (cpu)->cpu_id, (n))
558 
559 uint_t
560 workaround_errata(struct cpu *cpu)
561 {
562 	uint_t missing = 0;
563 
564 	ASSERT(cpu == CPU);
565 
566 	/*LINTED*/
567 	if (cpuid_opteron_erratum(cpu, 88) > 0) {
568 		/*
569 		 * SWAPGS May Fail To Read Correct GS Base
570 		 */
571 #if defined(OPTERON_ERRATUM_88)
572 		/*
573 		 * The workaround is an mfence in the relevant assembler code
574 		 */
575 #else
576 		WARNING(cpu, 88);
577 		missing++;
578 #endif
579 	}
580 
581 	if (cpuid_opteron_erratum(cpu, 91) > 0) {
582 		/*
583 		 * Software Prefetches May Report A Page Fault
584 		 */
585 #if defined(OPTERON_ERRATUM_91)
586 		/*
587 		 * fix is in trap.c
588 		 */
589 		opteron_erratum_91++;
590 #else
591 		WARNING(cpu, 91);
592 		missing++;
593 #endif
594 	}
595 
596 	if (cpuid_opteron_erratum(cpu, 93) > 0) {
597 		/*
598 		 * RSM Auto-Halt Restart Returns to Incorrect RIP
599 		 */
600 #if defined(OPTERON_ERRATUM_93)
601 		/*
602 		 * fix is in trap.c
603 		 */
604 		opteron_erratum_93++;
605 #else
606 		WARNING(cpu, 93);
607 		missing++;
608 #endif
609 	}
610 
611 	/*LINTED*/
612 	if (cpuid_opteron_erratum(cpu, 95) > 0) {
613 		/*
614 		 * RET Instruction May Return to Incorrect EIP
615 		 */
616 #if defined(OPTERON_ERRATUM_95)
617 #if defined(_LP64)
618 		/*
619 		 * Workaround this by ensuring that 32-bit user code and
620 		 * 64-bit kernel code never occupy the same address
621 		 * range mod 4G.
622 		 */
623 		if (_userlimit32 > 0xc0000000ul)
624 			*(uintptr_t *)&_userlimit32 = 0xc0000000ul;
625 
626 		/*LINTED*/
627 		ASSERT((uint32_t)COREHEAP_BASE == 0xc0000000u);
628 #endif	/* _LP64 */
629 #else
630 		WARNING(cpu, 95);
631 		missing++;
632 #endif	/* OPTERON_ERRATUM_95 */
633 	}
634 
635 	if (cpuid_opteron_erratum(cpu, 100) > 0) {
636 		/*
637 		 * Compatibility Mode Branches Transfer to Illegal Address
638 		 */
639 #if defined(OPTERON_ERRATUM_100)
640 		/*
641 		 * fix is in trap.c
642 		 */
643 		opteron_erratum_100++;
644 #else
645 		WARNING(cpu, 100);
646 		missing++;
647 #endif
648 	}
649 
650 	/*LINTED*/
651 	if (cpuid_opteron_erratum(cpu, 108) > 0) {
652 		/*
653 		 * CPUID Instruction May Return Incorrect Model Number In
654 		 * Some Processors
655 		 */
656 #if defined(OPTERON_ERRATUM_108)
657 		/*
658 		 * (Our cpuid-handling code corrects the model number on
659 		 * those processors)
660 		 */
661 #else
662 		WARNING(cpu, 108);
663 		missing++;
664 #endif
665 	}
666 
667 	/*LINTED*/
668 	if (cpuid_opteron_erratum(cpu, 109) > 0) {
669 		/*
670 		 * Certain Reverse REP MOVS May Produce Unpredictable Behaviour
671 		 */
672 #if defined(OPTERON_ERRATUM_109)
673 
674 		/* workaround is to print a warning to upgrade BIOS */
675 		if (rdmsr(MSR_AMD_PATCHLEVEL) == 0)
676 			opteron_erratum_109++;
677 #else
678 		WARNING(cpu, 109);
679 		missing++;
680 #endif
681 	}
682 	/*LINTED*/
683 	if (cpuid_opteron_erratum(cpu, 121) > 0) {
684 		/*
685 		 * Sequential Execution Across Non_Canonical Boundary Caused
686 		 * Processor Hang
687 		 */
688 #if defined(OPTERON_ERRATUM_121)
689 		static int	lma;
690 
691 		if (opteron_erratum_121)
692 			opteron_erratum_121++;
693 
694 		/*
695 		 * Erratum 121 is only present in long (64 bit) mode.
696 		 * Workaround is to include the page immediately before the
697 		 * va hole to eliminate the possibility of system hangs due to
698 		 * sequential execution across the va hole boundary.
699 		 */
700 		if (lma == 0) {
701 			/*
702 			 * check LMA once: assume all cpus are in long mode
703 			 * or not.
704 			 */
705 			lma = 1;
706 
707 			if (rdmsr(MSR_AMD_EFER) & AMD_EFER_LMA) {
708 				if (hole_start) {
709 					hole_start -= PAGESIZE;
710 				} else {
711 					/*
712 					 * hole_start not yet initialized by
713 					 * mmu_init. Initialize hole_start
714 					 * with value to be subtracted.
715 					 */
716 					hole_start = PAGESIZE;
717 				}
718 				opteron_erratum_121++;
719 			}
720 		}
721 #else
722 		WARNING(cpu, 121);
723 		missing++;
724 #endif
725 	}
726 
727 	/*LINTED*/
728 	if (cpuid_opteron_erratum(cpu, 122) > 0) {
729 		/*
730 		 * TLB Flush Filter May Cause Cohenrency Problem in
731 		 * Multiprocessor Systems
732 		 */
733 #if defined(OPTERON_ERRATUM_122)
734 		/*
735 		 * Erratum 122 is only present in MP configurations (multi-core
736 		 * or multi-processor).
737 		 */
738 
739 		if (opteron_erratum_122 || lgrp_plat_node_cnt > 1 ||
740 		    cpuid_get_ncpu_per_chip(cpu) > 1) {
741 			/* disable TLB Flush Filter */
742 			wrmsr(MSR_AMD_HWCR, rdmsr(MSR_AMD_HWCR) |
743 			    (uint64_t)(uintptr_t)AMD_HWCR_FFDIS);
744 			opteron_erratum_122++;
745 		}
746 
747 #else
748 		WARNING(cpu, 122);
749 		missing++;
750 #endif
751 	}
752 
753 #if defined(OPTERON_ERRATUM_123)
754 	/*LINTED*/
755 	if (cpuid_opteron_erratum(cpu, 123) > 0) {
756 		/*
757 		 * Bypassed Reads May Cause Data Corruption of System Hang in
758 		 * Dual Core Processors
759 		 */
760 		/*
761 		 * Erratum 123 applies only to multi-core cpus.
762 		 */
763 
764 		if (cpuid_get_ncpu_per_chip(cpu) > 1) {
765 			/* workaround is to print a warning to upgrade BIOS */
766 			if (rdmsr(MSR_AMD_PATCHLEVEL) == 0)
767 				opteron_erratum_123++;
768 		}
769 	}
770 #endif
771 
772 #if defined(OPTERON_ERRATUM_131)
773 	/*LINTED*/
774 	if (cpuid_opteron_erratum(cpu, 131) > 0) {
775 		/*
776 		 * Multiprocessor Systems with Four or More Cores May Deadlock
777 		 * Waiting for a Probe Response
778 		 */
779 		/*
780 		 * Erratum 131 applies to any system with four or more cores.
781 		 */
782 		if ((opteron_erratum_131 == 0) && ((lgrp_plat_node_cnt *
783 		    cpuid_get_ncpu_per_chip(cpu)) >= 4)) {
784 			/*
785 			 * Workaround is to print a warning to upgrade
786 			 * the BIOS
787 			 */
788 			if (!(rdmsr(MSR_AMD_NB_CFG) & AMD_NB_CFG_SRQ_HEARTBEAT))
789 				opteron_erratum_131++;
790 		}
791 	}
792 #endif
793 
794 #if defined(OPTERON_WORKAROUND_6336786)
795 	/*
796 	 * This isn't really erratum, but for convenience the
797 	 * detection/workaround code lives here and in cpuid_opteron_erratum.
798 	 */
799 	if (cpuid_opteron_erratum(cpu, 6336786) > 0) {
800 		int	node;
801 		uint8_t data;
802 
803 		/*
804 		 * Disable C1-Clock ramping on multi-core/multi-processor
805 		 * K8 platforms to guard against TSC drift.
806 		 */
807 		if (opteron_workaround_6336786) {
808 			opteron_workaround_6336786++;
809 		} else if ((lgrp_plat_node_cnt *
810 		    cpuid_get_ncpu_per_chip(cpu) >= 2) ||
811 		    opteron_workaround_6336786_UP) {
812 			for (node = 0; node < lgrp_plat_node_cnt; node++) {
813 				/*
814 				 * Clear PMM7[1:0] (function 3, offset 0x87)
815 				 * Northbridge device is the node id + 24.
816 				 */
817 				data = pci_getb_func(0, node + 24, 3, 0x87);
818 				data &= 0xFC;
819 				pci_putb_func(0, node + 24, 3, 0x87, data);
820 			}
821 			opteron_workaround_6336786++;
822 		}
823 	}
824 #endif
825 	return (missing);
826 }
827 
828 void
829 workaround_errata_end()
830 {
831 #if defined(OPTERON_ERRATUM_109)
832 	if (opteron_erratum_109) {
833 		cmn_err(CE_WARN,
834 		    "BIOS microcode patch for AMD Athlon(tm) 64/Opteron(tm)"
835 		    " processor\nerratum 109 was not detected; updating your"
836 		    " system's BIOS to a version\ncontaining this"
837 		    " microcode patch is HIGHLY recommended or erroneous"
838 		    " system\noperation may occur.\n");
839 	}
840 #endif	/* OPTERON_ERRATUM_109 */
841 #if defined(OPTERON_ERRATUM_123)
842 	if (opteron_erratum_123) {
843 		cmn_err(CE_WARN,
844 		    "BIOS microcode patch for AMD Athlon(tm) 64/Opteron(tm)"
845 		    " processor\nerratum 123 was not detected; updating your"
846 		    " system's BIOS to a version\ncontaining this"
847 		    " microcode patch is HIGHLY recommended or erroneous"
848 		    " system\noperation may occur.\n");
849 	}
850 #endif	/* OPTERON_ERRATUM_123 */
851 #if defined(OPTERON_ERRATUM_131)
852 	if (opteron_erratum_131) {
853 		cmn_err(CE_WARN,
854 		    "BIOS microcode patch for AMD Athlon(tm) 64/Opteron(tm)"
855 		    " processor\nerratum 131 was not detected; updating your"
856 		    " system's BIOS to a version\ncontaining this"
857 		    " microcode patch is HIGHLY recommended or erroneous"
858 		    " system\noperation may occur.\n");
859 	}
860 #endif	/* OPTERON_ERRATUM_131 */
861 }
862 
863 static ushort_t *mp_map_warm_reset_vector();
864 static void mp_unmap_warm_reset_vector(ushort_t *warm_reset_vector);
865 
866 /*ARGSUSED*/
867 void
868 start_other_cpus(int cprboot)
869 {
870 	unsigned who;
871 	int cpuid = 0;
872 	int delays = 0;
873 	int started_cpu;
874 	ushort_t *warm_reset_vector = NULL;
875 	extern int procset;
876 
877 	/*
878 	 * Initialize our own cpu_info.
879 	 */
880 	init_cpu_info(CPU);
881 
882 	/*
883 	 * Initialize our syscall handlers
884 	 */
885 	init_cpu_syscall(CPU);
886 
887 	/*
888 	 * if only 1 cpu or not using MP, skip the rest of this
889 	 */
890 	if (!(mp_cpus & ~(1 << cpuid)) || use_mp == 0) {
891 		if (use_mp == 0)
892 			cmn_err(CE_CONT, "?***** Not in MP mode\n");
893 		goto done;
894 	}
895 
896 	/*
897 	 * perform such initialization as is needed
898 	 * to be able to take CPUs on- and off-line.
899 	 */
900 	cpu_pause_init();
901 
902 	xc_init();		/* initialize processor crosscalls */
903 
904 	/*
905 	 * Copy the real mode code at "real_mode_start" to the
906 	 * page at rm_platter_va.
907 	 */
908 	warm_reset_vector = mp_map_warm_reset_vector();
909 	if (warm_reset_vector == NULL)
910 		goto done;
911 
912 	bcopy((caddr_t)real_mode_start,
913 	    (caddr_t)((rm_platter_t *)rm_platter_va)->rm_code,
914 	    (size_t)real_mode_end - (size_t)real_mode_start);
915 
916 	flushes_require_xcalls = 1;
917 
918 	affinity_set(CPU_CURRENT);
919 
920 	for (who = 0; who < NCPU; who++) {
921 		if (who == cpuid)
922 			continue;
923 
924 		if ((mp_cpus & (1 << who)) == 0)
925 			continue;
926 
927 		mp_startup_init(who);
928 		started_cpu = 1;
929 		(*cpu_startf)(who, rm_platter_pa);
930 
931 		while ((procset & (1 << who)) == 0) {
932 
933 			delay(1);
934 			if (++delays > (20 * hz)) {
935 
936 				cmn_err(CE_WARN,
937 				    "cpu%d failed to start", who);
938 
939 				mutex_enter(&cpu_lock);
940 				cpu[who]->cpu_flags = 0;
941 				cpu_vm_data_destroy(cpu[who]);
942 				cpu_del_unit(who);
943 				mutex_exit(&cpu_lock);
944 
945 				started_cpu = 0;
946 				break;
947 			}
948 		}
949 		if (!started_cpu)
950 			continue;
951 		if (tsc_gethrtime_enable)
952 			tsc_sync_master(who);
953 
954 
955 		if (dtrace_cpu_init != NULL) {
956 			/*
957 			 * DTrace CPU initialization expects cpu_lock
958 			 * to be held.
959 			 */
960 			mutex_enter(&cpu_lock);
961 			(*dtrace_cpu_init)(who);
962 			mutex_exit(&cpu_lock);
963 		}
964 	}
965 
966 	affinity_clear();
967 
968 	for (who = 0; who < NCPU; who++) {
969 		if (who == cpuid)
970 			continue;
971 
972 		if (!(procset & (1 << who)))
973 			continue;
974 
975 		while (!(cpu_ready_set & (1 << who)))
976 			delay(1);
977 	}
978 
979 done:
980 	workaround_errata_end();
981 
982 	if (warm_reset_vector != NULL)
983 		mp_unmap_warm_reset_vector(warm_reset_vector);
984 	hat_unload(kas.a_hat, (caddr_t)(uintptr_t)rm_platter_pa, MMU_PAGESIZE,
985 	    HAT_UNLOAD);
986 }
987 
988 /*
989  * Dummy functions - no i86pc platforms support dynamic cpu allocation.
990  */
991 /*ARGSUSED*/
992 int
993 mp_cpu_configure(int cpuid)
994 {
995 	return (ENOTSUP);		/* not supported */
996 }
997 
998 /*ARGSUSED*/
999 int
1000 mp_cpu_unconfigure(int cpuid)
1001 {
1002 	return (ENOTSUP);		/* not supported */
1003 }
1004 
1005 /*
1006  * Startup function for 'other' CPUs (besides boot cpu).
1007  * Resumed from cpu_startup.
1008  *
1009  * WARNING: until CPU_READY is set, mp_startup and routines called by
1010  * mp_startup should not call routines (e.g. kmem_free) that could call
1011  * hat_unload which requires CPU_READY to be set.
1012  */
1013 void
1014 mp_startup(void)
1015 {
1016 	struct cpu *cp = CPU;
1017 	extern int procset;
1018 	uint_t new_x86_feature;
1019 
1020 	new_x86_feature = cpuid_pass1(cp);
1021 
1022 	/*
1023 	 * We need to Sync MTRR with cpu0's MTRR. We have to do
1024 	 * this with interrupts disabled.
1025 	 */
1026 	if (x86_feature & X86_MTRR)
1027 		mtrr_sync();
1028 
1029 	/*
1030 	 * Initialize this CPU's syscall handlers
1031 	 */
1032 	init_cpu_syscall(cp);
1033 
1034 	/*
1035 	 * Enable interrupts with spl set to LOCK_LEVEL. LOCK_LEVEL is the
1036 	 * highest level at which a routine is permitted to block on
1037 	 * an adaptive mutex (allows for cpu poke interrupt in case
1038 	 * the cpu is blocked on a mutex and halts). Setting LOCK_LEVEL blocks
1039 	 * device interrupts that may end up in the hat layer issuing cross
1040 	 * calls before CPU_READY is set.
1041 	 */
1042 	(void) splx(ipltospl(LOCK_LEVEL));
1043 
1044 	/*
1045 	 * Do a sanity check to make sure this new CPU is a sane thing
1046 	 * to add to the collection of processors running this system.
1047 	 *
1048 	 * XXX	Clearly this needs to get more sophisticated, if x86
1049 	 * systems start to get built out of heterogenous CPUs; as is
1050 	 * likely to happen once the number of processors in a configuration
1051 	 * gets large enough.
1052 	 */
1053 	if ((x86_feature & new_x86_feature) != x86_feature) {
1054 		cmn_err(CE_CONT, "?cpu%d: %b\n",
1055 		    cp->cpu_id, new_x86_feature, FMT_X86_FEATURE);
1056 		cmn_err(CE_WARN, "cpu%d feature mismatch", cp->cpu_id);
1057 	}
1058 
1059 	/*
1060 	 * We could be more sophisticated here, and just mark the CPU
1061 	 * as "faulted" but at this point we'll opt for the easier
1062 	 * answer of dieing horribly.  Provided the boot cpu is ok,
1063 	 * the system can be recovered by booting with use_mp set to zero.
1064 	 */
1065 	if (workaround_errata(cp) != 0)
1066 		panic("critical workaround(s) missing for cpu%d", cp->cpu_id);
1067 
1068 	cpuid_pass2(cp);
1069 	cpuid_pass3(cp);
1070 	(void) cpuid_pass4(cp);
1071 
1072 	init_cpu_info(cp);
1073 
1074 	mutex_enter(&cpu_lock);
1075 	procset |= 1 << cp->cpu_id;
1076 	mutex_exit(&cpu_lock);
1077 
1078 	if (tsc_gethrtime_enable)
1079 		tsc_sync_slave();
1080 
1081 	mutex_enter(&cpu_lock);
1082 	/*
1083 	 * It's unfortunate that chip_cpu_init() has to be called here.
1084 	 * It really belongs in cpu_add_unit(), but unfortunately it is
1085 	 * dependent on the cpuid probing, which must be done in the
1086 	 * context of the current CPU. Care must be taken on x86 to ensure
1087 	 * that mp_startup can safely block even though chip_cpu_init() and
1088 	 * cpu_add_active() have not yet been called.
1089 	 */
1090 	chip_cpu_init(cp);
1091 	chip_cpu_startup(cp);
1092 
1093 	cp->cpu_flags |= CPU_RUNNING | CPU_READY | CPU_ENABLE | CPU_EXISTS;
1094 	cpu_add_active(cp);
1095 	mutex_exit(&cpu_lock);
1096 
1097 	add_cpunode2devtree(cp->cpu_id, cp->cpu_m.mcpu_cpi);
1098 
1099 	(void) spl0();				/* enable interrupts */
1100 
1101 	/*
1102 	 * Set up the CPU module for this CPU.  This can't be done before
1103 	 * this CPU is made CPU_READY, because we may (in heterogeneous systems)
1104 	 * need to go load another CPU module.  The act of attempting to load
1105 	 * a module may trigger a cross-call, which will ASSERT unless this
1106 	 * cpu is CPU_READY.
1107 	 */
1108 	cmi_init();
1109 
1110 	if (x86_feature & X86_MCA)
1111 		cmi_mca_init();
1112 
1113 	if (boothowto & RB_DEBUG)
1114 		kdi_dvec_cpu_init(cp);
1115 
1116 	/*
1117 	 * Setting the bit in cpu_ready_set must be the last operation in
1118 	 * processor initialization; the boot CPU will continue to boot once
1119 	 * it sees this bit set for all active CPUs.
1120 	 */
1121 	CPUSET_ATOMIC_ADD(cpu_ready_set, cp->cpu_id);
1122 
1123 	/*
1124 	 * Because mp_startup() gets fired off after init() starts, we
1125 	 * can't use the '?' trick to do 'boot -v' printing - so we
1126 	 * always direct the 'cpu .. online' messages to the log.
1127 	 */
1128 	cmn_err(CE_CONT, "!cpu%d initialization complete - online\n",
1129 	    cp->cpu_id);
1130 
1131 	/*
1132 	 * Now we are done with the startup thread, so free it up.
1133 	 */
1134 	thread_exit();
1135 	panic("mp_startup: cannot return");
1136 	/*NOTREACHED*/
1137 }
1138 
1139 
1140 /*
1141  * Start CPU on user request.
1142  */
1143 /* ARGSUSED */
1144 int
1145 mp_cpu_start(struct cpu *cp)
1146 {
1147 	ASSERT(MUTEX_HELD(&cpu_lock));
1148 	return (0);
1149 }
1150 
1151 /*
1152  * Stop CPU on user request.
1153  */
1154 /* ARGSUSED */
1155 int
1156 mp_cpu_stop(struct cpu *cp)
1157 {
1158 	extern int cbe_psm_timer_mode;
1159 	ASSERT(MUTEX_HELD(&cpu_lock));
1160 
1161 	/*
1162 	 * If TIMER_PERIODIC mode is used, CPU0 is the one running it;
1163 	 * can't stop it.  (This is true only for machines with no TSC.)
1164 	 */
1165 
1166 	if ((cbe_psm_timer_mode == TIMER_PERIODIC) && (cp->cpu_id == 0))
1167 		return (1);
1168 
1169 	return (0);
1170 }
1171 
1172 /*
1173  * Power on CPU.
1174  */
1175 /* ARGSUSED */
1176 int
1177 mp_cpu_poweron(struct cpu *cp)
1178 {
1179 	ASSERT(MUTEX_HELD(&cpu_lock));
1180 	return (ENOTSUP);		/* not supported */
1181 }
1182 
1183 /*
1184  * Power off CPU.
1185  */
1186 /* ARGSUSED */
1187 int
1188 mp_cpu_poweroff(struct cpu *cp)
1189 {
1190 	ASSERT(MUTEX_HELD(&cpu_lock));
1191 	return (ENOTSUP);		/* not supported */
1192 }
1193 
1194 
1195 /*
1196  * Take the specified CPU out of participation in interrupts.
1197  */
1198 int
1199 cpu_disable_intr(struct cpu *cp)
1200 {
1201 	if (psm_disable_intr(cp->cpu_id) != DDI_SUCCESS)
1202 		return (EBUSY);
1203 
1204 	cp->cpu_flags &= ~CPU_ENABLE;
1205 	return (0);
1206 }
1207 
1208 /*
1209  * Allow the specified CPU to participate in interrupts.
1210  */
1211 void
1212 cpu_enable_intr(struct cpu *cp)
1213 {
1214 	ASSERT(MUTEX_HELD(&cpu_lock));
1215 	cp->cpu_flags |= CPU_ENABLE;
1216 	psm_enable_intr(cp->cpu_id);
1217 }
1218 
1219 
1220 
1221 static ushort_t *
1222 mp_map_warm_reset_vector()
1223 {
1224 	ushort_t *warm_reset_vector;
1225 
1226 	if (!(warm_reset_vector = (ushort_t *)psm_map_phys(WARM_RESET_VECTOR,
1227 	    sizeof (ushort_t *), PROT_READ|PROT_WRITE)))
1228 		return (NULL);
1229 
1230 	/*
1231 	 * setup secondary cpu bios boot up vector
1232 	 */
1233 	*warm_reset_vector = (ushort_t)((caddr_t)
1234 		((struct rm_platter *)rm_platter_va)->rm_code - rm_platter_va
1235 		+ ((ulong_t)rm_platter_va & 0xf));
1236 	warm_reset_vector++;
1237 	*warm_reset_vector = (ushort_t)(rm_platter_pa >> 4);
1238 
1239 	--warm_reset_vector;
1240 	return (warm_reset_vector);
1241 }
1242 
1243 static void
1244 mp_unmap_warm_reset_vector(ushort_t *warm_reset_vector)
1245 {
1246 	psm_unmap_phys((caddr_t)warm_reset_vector, sizeof (ushort_t *));
1247 }
1248 
1249 void
1250 mp_cpu_faulted_enter(struct cpu *cp)
1251 {
1252 	cmi_faulted_enter(cp);
1253 }
1254 
1255 void
1256 mp_cpu_faulted_exit(struct cpu *cp)
1257 {
1258 	cmi_faulted_exit(cp);
1259 }
1260 
1261 /*
1262  * The following two routines are used as context operators on threads belonging
1263  * to processes with a private LDT (see sysi86).  Due to the rarity of such
1264  * processes, these routines are currently written for best code readability and
1265  * organization rather than speed.  We could avoid checking x86_feature at every
1266  * context switch by installing different context ops, depending on the
1267  * x86_feature flags, at LDT creation time -- one for each combination of fast
1268  * syscall feature flags.
1269  */
1270 
1271 /*ARGSUSED*/
1272 void
1273 cpu_fast_syscall_disable(void *arg)
1274 {
1275 	if (x86_feature & X86_SEP)
1276 		cpu_sep_disable();
1277 	if (x86_feature & X86_ASYSC)
1278 		cpu_asysc_disable();
1279 }
1280 
1281 /*ARGSUSED*/
1282 void
1283 cpu_fast_syscall_enable(void *arg)
1284 {
1285 	if (x86_feature & X86_SEP)
1286 		cpu_sep_enable();
1287 	if (x86_feature & X86_ASYSC)
1288 		cpu_asysc_enable();
1289 }
1290 
1291 static void
1292 cpu_sep_enable(void)
1293 {
1294 	ASSERT(x86_feature & X86_SEP);
1295 	ASSERT(curthread->t_preempt || getpil() >= LOCK_LEVEL);
1296 
1297 	wrmsr(MSR_INTC_SEP_CS, (uint64_t)(uintptr_t)KCS_SEL);
1298 }
1299 
1300 static void
1301 cpu_sep_disable(void)
1302 {
1303 	ASSERT(x86_feature & X86_SEP);
1304 	ASSERT(curthread->t_preempt || getpil() >= LOCK_LEVEL);
1305 
1306 	/*
1307 	 * Setting the SYSENTER_CS_MSR register to 0 causes software executing
1308 	 * the sysenter or sysexit instruction to trigger a #gp fault.
1309 	 */
1310 	wrmsr(MSR_INTC_SEP_CS, 0ULL);
1311 }
1312 
1313 static void
1314 cpu_asysc_enable(void)
1315 {
1316 	ASSERT(x86_feature & X86_ASYSC);
1317 	ASSERT(curthread->t_preempt || getpil() >= LOCK_LEVEL);
1318 
1319 	wrmsr(MSR_AMD_EFER, rdmsr(MSR_AMD_EFER) |
1320 	    (uint64_t)(uintptr_t)AMD_EFER_SCE);
1321 }
1322 
1323 static void
1324 cpu_asysc_disable(void)
1325 {
1326 	ASSERT(x86_feature & X86_ASYSC);
1327 	ASSERT(curthread->t_preempt || getpil() >= LOCK_LEVEL);
1328 
1329 	/*
1330 	 * Turn off the SCE (syscall enable) bit in the EFER register. Software
1331 	 * executing syscall or sysret with this bit off will incur a #ud trap.
1332 	 */
1333 	wrmsr(MSR_AMD_EFER, rdmsr(MSR_AMD_EFER) &
1334 	    ~((uint64_t)(uintptr_t)AMD_EFER_SCE));
1335 }
1336