2 * Copyright (c) 1990 The Regents of the University of California.
5 * This code is derived from software contributed to Berkeley by
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 4. Neither the name of the University nor the names of its contributors
17 * may be used to endorse or promote products derived from this software
18 * without specific prior written permission.
20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
35 #include "opt_sched.h"
37 #include <machine/asmacros.h>
41 #if defined(SMP) && defined(SCHED_ULE)
43 #define BLOCK_SPIN(reg) \
44 movl $blocked_lock,%eax ; \
47 cmpxchgl %eax,TD_LOCK(reg) ; \
54 #define BLOCK_SPIN(reg)
57 /*****************************************************************************/
59 /*****************************************************************************/
66 * This is the second half of cpu_switch(). It is used when the current
67 * thread is either a dummy or slated to die, and we no longer care
68 * about its state. This is only a slight optimization and is probably
69 * not worth it anymore. Note that we need to clear the pm_active bits so
70 * we do need the old proc if it still exists.
76 movl PCPU(CPUID), %esi
77 movl 4(%esp),%ecx /* Old thread */
78 testl %ecx,%ecx /* no thread? */
80 /* release bit from old pm_active */
81 movl PCPU(CURPMAP), %ebx
85 btrl %esi, PM_ACTIVE(%ebx) /* clear old */
87 movl 8(%esp),%ecx /* New thread */
88 movl TD_PCB(%ecx),%edx
89 movl PCB_CR3(%edx),%eax
91 /* set bit in new pm_active */
92 movl TD_PROC(%ecx),%eax
93 movl P_VMSPACE(%eax), %ebx
95 movl %ebx, PCPU(CURPMAP)
99 btsl %esi, PM_ACTIVE(%ebx) /* set new */
104 * cpu_switch(old, new)
106 * Save the current thread state, then select the next thread to run
107 * and load its state.
115 /* Switch to new thread. First, save context. */
119 testl %ecx,%ecx /* no thread? */
120 jz badsw2 /* no, panic */
123 movl TD_PCB(%ecx),%edx
125 movl (%esp),%eax /* Hardware registers */
126 movl %eax,PCB_EIP(%edx)
127 movl %ebx,PCB_EBX(%edx)
128 movl %esp,PCB_ESP(%edx)
129 movl %ebp,PCB_EBP(%edx)
130 movl %esi,PCB_ESI(%edx)
131 movl %edi,PCB_EDI(%edx)
135 /* Test if debug registers should be saved. */
136 testl $PCB_DBREGS,PCB_FLAGS(%edx)
137 jz 1f /* no, skip over */
138 movl %dr7,%eax /* yes, do the save */
139 movl %eax,PCB_DR7(%edx)
140 andl $0x0000fc00, %eax /* disable all watchpoints */
143 movl %eax,PCB_DR6(%edx)
145 movl %eax,PCB_DR3(%edx)
147 movl %eax,PCB_DR2(%edx)
149 movl %eax,PCB_DR1(%edx)
151 movl %eax,PCB_DR0(%edx)
154 /* have we used fp, and need a save? */
155 cmpl %ecx,PCPU(FPCURTHREAD)
157 pushl PCB_SAVEFPU(%edx) /* h/w bugs make saving complicated */
158 call npxsave /* do it in a big C function */
162 /* Save is done. Now fire up new thread. Leave old vmspace. */
164 movl 8(%esp),%ecx /* New thread */
165 movl 12(%esp),%esi /* New lock */
167 testl %ecx,%ecx /* no thread? */
168 jz badsw3 /* no, panic */
170 movl TD_PCB(%ecx),%edx
172 /* switch address space */
173 movl PCB_CR3(%edx),%eax
174 movl %cr3,%ebx /* The same address space? */
177 movl %eax,%cr3 /* new address space */
179 movl PCPU(CPUID),%esi
180 SETOP %eax,TD_LOCK(%edi) /* Switchout td_lock */
182 /* Release bit from old pmap->pm_active */
183 movl PCPU(CURPMAP), %ebx
187 btrl %esi, PM_ACTIVE(%ebx) /* clear old */
189 /* Set bit in new pmap->pm_active */
190 movl TD_PROC(%ecx),%eax /* newproc */
191 movl P_VMSPACE(%eax), %ebx
193 movl %ebx, PCPU(CURPMAP)
197 btsl %esi, PM_ACTIVE(%ebx) /* set new */
201 SETOP %esi,TD_LOCK(%edi) /* Switchout td_lock */
205 * At this point, we've switched address spaces and are ready
206 * to load up the rest of the next context.
208 cmpl $0, PCB_EXT(%edx) /* has pcb extension? */
209 je 1f /* If not, use the default */
210 movl $1, PCPU(PRIVATE_TSS) /* mark use of private tss */
211 movl PCB_EXT(%edx), %edi /* new tss descriptor */
212 jmp 2f /* Load it up */
215 * Use the common default TSS instead of our own.
216 * Set our stack pointer into the TSS, it's set to just
217 * below the PCB. In C, common_tss.tss_esp0 = &pcb - 16;
219 leal -16(%edx), %ebx /* leave space for vm86 */
220 movl %ebx, PCPU(COMMON_TSS) + TSS_ESP0
223 * Test this CPU's bit in the bitmap to see if this
224 * CPU was using a private TSS.
226 cmpl $0, PCPU(PRIVATE_TSS) /* Already using the common? */
227 je 3f /* if so, skip reloading */
228 movl $0, PCPU(PRIVATE_TSS)
229 PCPU_ADDR(COMMON_TSSD, %edi)
231 /* Move correct tss descriptor into GDT slot, then reload tr. */
232 movl PCPU(TSS_GDT), %ebx /* entry in GDT */
237 movl $GPROC0_SEL*8, %esi /* GSEL(GPROC0_SEL, SEL_KPL) */
241 /* Copy the %fs and %gs selectors into this pcpu gdt */
242 leal PCB_FSD(%edx), %esi
243 movl PCPU(FSGS_GDT), %edi
244 movl 0(%esi), %eax /* %fs selector */
248 movl 8(%esi), %eax /* %gs selector, comes straight after */
253 /* Restore context. */
254 movl PCB_EBX(%edx),%ebx
255 movl PCB_ESP(%edx),%esp
256 movl PCB_EBP(%edx),%ebp
257 movl PCB_ESI(%edx),%esi
258 movl PCB_EDI(%edx),%edi
259 movl PCB_EIP(%edx),%eax
264 movl %edx, PCPU(CURPCB)
265 movl TD_TID(%ecx),%eax
266 movl %ecx, PCPU(CURTHREAD) /* into next thread */
269 * Determine the LDT to use and load it if is the default one and
270 * that is not the current one.
272 movl TD_PROC(%ecx),%eax
273 cmpl $0,P_MD+MD_LDT(%eax)
275 movl _default_ldt,%eax
276 cmpl PCPU(CURRENTLDT),%eax
279 movl %eax,PCPU(CURRENTLDT)
282 /* Load the LDT when it is not the default one. */
283 pushl %edx /* Preserve pointer to pcb. */
284 addl $P_MD,%eax /* Pointer to mdproc is arg. */
291 /* This must be done after loading the user LDT. */
292 .globl cpu_switch_load_gs
297 pushl PCPU(CURTHREAD)
302 /* Test if debug registers should be restored. */
303 testl $PCB_DBREGS,PCB_FLAGS(%edx)
307 * Restore debug registers. The special code for dr7 is to
308 * preserve the current values of its reserved bits.
310 movl PCB_DR6(%edx),%eax
312 movl PCB_DR3(%edx),%eax
314 movl PCB_DR2(%edx),%eax
316 movl PCB_DR1(%edx),%eax
318 movl PCB_DR0(%edx),%eax
321 andl $0x0000fc00,%eax
322 movl PCB_DR7(%edx),%ecx
323 andl $~0x0000fc00,%ecx
334 sw0_1: .asciz "cpu_throw: no newthread supplied"
340 sw0_2: .asciz "cpu_switch: no curthread supplied"
346 sw0_3: .asciz "cpu_switch: no newthread supplied"
352 * Update pcb, saving current processor state.
358 /* Save caller's return address. Child won't execute this routine. */
360 movl %eax,PCB_EIP(%ecx)
363 movl %eax,PCB_CR3(%ecx)
365 movl %ebx,PCB_EBX(%ecx)
366 movl %esp,PCB_ESP(%ecx)
367 movl %ebp,PCB_EBP(%ecx)
368 movl %esi,PCB_ESI(%ecx)
369 movl %edi,PCB_EDI(%ecx)
375 movl %eax,PCB_CR0(%ecx)
377 movl %eax,PCB_CR2(%ecx)
379 movl %eax,PCB_CR4(%ecx)
382 movl %eax,PCB_DR0(%ecx)
384 movl %eax,PCB_DR1(%ecx)
386 movl %eax,PCB_DR2(%ecx)
388 movl %eax,PCB_DR3(%ecx)
390 movl %eax,PCB_DR6(%ecx)
392 movl %eax,PCB_DR7(%ecx)
409 * resumectx(pcb) __fastcall
410 * Resuming processor state from pcb.
416 /* Restore segment registers */
417 movzwl PCB_DS(%ecx),%eax
419 movzwl PCB_ES(%ecx),%eax
421 movzwl PCB_FS(%ecx),%eax
423 movzwl PCB_GS(%ecx),%eax
425 movzwl PCB_SS(%ecx),%eax
428 /* Restore CR2, CR4, CR3 and CR0 */
429 movl PCB_CR2(%ecx),%eax
431 movl PCB_CR4(%ecx),%eax
433 movl PCB_CR3(%ecx),%eax
435 movl PCB_CR0(%ecx),%eax
440 /* Restore descriptor tables */
444 #define SDT_SYS386TSS 9
445 #define SDT_SYS386BSY 11
446 /* Clear "task busy" bit and reload TR */
447 movl PCPU(TSS_GDT),%eax
448 andb $(~SDT_SYS386BSY | SDT_SYS386TSS),5(%eax)
449 movzwl PCB_TR(%ecx),%eax
454 /* Restore debug registers */
455 movl PCB_DR0(%ecx),%eax
457 movl PCB_DR1(%ecx),%eax
459 movl PCB_DR2(%ecx),%eax
461 movl PCB_DR3(%ecx),%eax
463 movl PCB_DR6(%ecx),%eax
465 movl PCB_DR7(%ecx),%eax
468 /* Restore other registers */
469 movl PCB_EDI(%ecx),%edi
470 movl PCB_ESI(%ecx),%esi
471 movl PCB_EBP(%ecx),%ebp
472 movl PCB_ESP(%ecx),%esp
473 movl PCB_EBX(%ecx),%ebx
475 /* reload code selector by turning return into intersegmental return */