1 /*-
2 * Copyright (c) 1982, 1986 The Regents of the University of California.
3 * Copyright (c) 1989, 1990 William Jolitz
4 * Copyright (c) 1994 John Dyson
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to Berkeley by
8 * the Systems Programming Group of the University of Utah Computer
9 * Science Department, and William Jolitz.
10 *
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
13 * are met:
14 * 1. Redistributions of source code must retain the above copyright
15 * notice, this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 * notice, this list of conditions and the following disclaimer in the
18 * documentation and/or other materials provided with the distribution.
19 * 3. All advertising materials mentioning features or use of this software
20 * must display the following acknowledgement:
21 * This product includes software developed by the University of
22 * California, Berkeley and its contributors.
23 * 4. Neither the name of the University nor the names of its contributors
24 * may be used to endorse or promote products derived from this software
25 * without specific prior written permission.
26 *
27 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
28 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
29 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
30 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
31 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
32 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
33 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
34 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
35 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
36 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
37 * SUCH DAMAGE.
38 *
39 * from: @(#)vm_machdep.c 7.3 (Berkeley) 5/13/91
40 * Utah $Hdr: vm_machdep.c 1.16.1.1 89/06/23$
41 */
42
43 #include <sys/cdefs.h>
44 __FBSDID("$FreeBSD$");
45
46 #include "opt_isa.h"
47 #include "opt_cpu.h"
48 #include "opt_compat.h"
49
50 #include <sys/param.h>
51 #include <sys/systm.h>
52 #include <sys/bio.h>
53 #include <sys/buf.h>
54 #include <sys/kernel.h>
55 #include <sys/ktr.h>
56 #include <sys/lock.h>
57 #include <sys/malloc.h>
58 #include <sys/mbuf.h>
59 #include <sys/mutex.h>
60 #include <sys/pioctl.h>
61 #include <sys/proc.h>
62 #include <sys/smp.h>
63 #include <sys/sysctl.h>
64 #include <sys/sysent.h>
65 #include <sys/unistd.h>
66 #include <sys/vnode.h>
67 #include <sys/vmmeter.h>
68
69 #include <machine/cpu.h>
70 #include <machine/md_var.h>
71 #include <machine/pcb.h>
72 #include <machine/smp.h>
73 #include <machine/specialreg.h>
74 #include <machine/tss.h>
75
76 #include <vm/vm.h>
77 #include <vm/vm_extern.h>
78 #include <vm/vm_kern.h>
79 #include <vm/vm_page.h>
80 #include <vm/vm_map.h>
81 #include <vm/vm_param.h>
82
83 _Static_assert(OFFSETOF_CURTHREAD == offsetof(struct pcpu, pc_curthread),
84 "OFFSETOF_CURTHREAD does not correspond with offset of pc_curthread.");
85 _Static_assert(OFFSETOF_CURPCB == offsetof(struct pcpu, pc_curpcb),
86 "OFFSETOF_CURPCB does not correspond with offset of pc_curpcb.");
87 _Static_assert(OFFSETOF_MONITORBUF == offsetof(struct pcpu, pc_monitorbuf),
88 "OFFSETOF_MONITORBUF does not correspond with offset of pc_monitorbuf.");
89
90 struct savefpu *
get_pcb_user_save_td(struct thread * td)91 get_pcb_user_save_td(struct thread *td)
92 {
93 vm_offset_t p;
94
95 p = td->td_kstack + td->td_kstack_pages * PAGE_SIZE -
96 roundup2(cpu_max_ext_state_size, XSAVE_AREA_ALIGN);
97 KASSERT((p % XSAVE_AREA_ALIGN) == 0, ("Unaligned pcb_user_save area"));
98 return ((struct savefpu *)p);
99 }
100
101 struct savefpu *
get_pcb_user_save_pcb(struct pcb * pcb)102 get_pcb_user_save_pcb(struct pcb *pcb)
103 {
104 vm_offset_t p;
105
106 p = (vm_offset_t)(pcb + 1);
107 return ((struct savefpu *)p);
108 }
109
110 struct pcb *
get_pcb_td(struct thread * td)111 get_pcb_td(struct thread *td)
112 {
113 vm_offset_t p;
114
115 p = td->td_kstack + td->td_kstack_pages * PAGE_SIZE -
116 roundup2(cpu_max_ext_state_size, XSAVE_AREA_ALIGN) -
117 sizeof(struct pcb);
118 return ((struct pcb *)p);
119 }
120
121 void *
alloc_fpusave(int flags)122 alloc_fpusave(int flags)
123 {
124 void *res;
125 struct savefpu_ymm *sf;
126
127 res = malloc(cpu_max_ext_state_size, M_DEVBUF, flags);
128 if (use_xsave) {
129 sf = (struct savefpu_ymm *)res;
130 bzero(&sf->sv_xstate.sx_hd, sizeof(sf->sv_xstate.sx_hd));
131 sf->sv_xstate.sx_hd.xstate_bv = xsave_mask;
132 }
133 return (res);
134 }
135
136 /*
137 * Finish a fork operation, with process p2 nearly set up.
138 * Copy and update the pcb, set up the stack so that the child
139 * ready to run and return to user mode.
140 */
141 void
cpu_fork(struct thread * td1,struct proc * p2,struct thread * td2,int flags)142 cpu_fork(struct thread *td1, struct proc *p2, struct thread *td2, int flags)
143 {
144 struct proc *p1;
145 struct pcb *pcb2;
146 struct mdproc *mdp1, *mdp2;
147 struct proc_ldt *pldt;
148
149 p1 = td1->td_proc;
150 if ((flags & RFPROC) == 0) {
151 if ((flags & RFMEM) == 0) {
152 /* unshare user LDT */
153 mdp1 = &p1->p_md;
154 mtx_lock(&dt_lock);
155 if ((pldt = mdp1->md_ldt) != NULL &&
156 pldt->ldt_refcnt > 1 &&
157 user_ldt_alloc(p1, 1) == NULL)
158 panic("could not copy LDT");
159 mtx_unlock(&dt_lock);
160 }
161 return;
162 }
163
164 /* Ensure that td1's pcb is up to date. */
165 fpuexit(td1);
166 update_pcb_bases(td1->td_pcb);
167
168 /* Point the pcb to the top of the stack */
169 pcb2 = get_pcb_td(td2);
170 td2->td_pcb = pcb2;
171
172 /* Copy td1's pcb */
173 bcopy(td1->td_pcb, pcb2, sizeof(*pcb2));
174
175 /* Properly initialize pcb_save */
176 pcb2->pcb_save = get_pcb_user_save_pcb(pcb2);
177 bcopy(get_pcb_user_save_td(td1), get_pcb_user_save_pcb(pcb2),
178 cpu_max_ext_state_size);
179
180 /* Point mdproc and then copy over td1's contents */
181 mdp2 = &p2->p_md;
182 bcopy(&p1->p_md, mdp2, sizeof(*mdp2));
183
184 /*
185 * Create a new fresh stack for the new process.
186 * Copy the trap frame for the return to user mode as if from a
187 * syscall. This copies most of the user mode register values.
188 */
189 td2->td_frame = (struct trapframe *)td2->td_pcb - 1;
190 bcopy(td1->td_frame, td2->td_frame, sizeof(struct trapframe));
191
192 td2->td_frame->tf_rax = 0; /* Child returns zero */
193 td2->td_frame->tf_rflags &= ~PSL_C; /* success */
194 td2->td_frame->tf_rdx = 1;
195
196 /*
197 * If the parent process has the trap bit set (i.e. a debugger had
198 * single stepped the process to the system call), we need to clear
199 * the trap flag from the new frame unless the debugger had set PF_FORK
200 * on the parent. Otherwise, the child will receive a (likely
201 * unexpected) SIGTRAP when it executes the first instruction after
202 * returning to userland.
203 */
204 if ((p1->p_pfsflags & PF_FORK) == 0)
205 td2->td_frame->tf_rflags &= ~PSL_T;
206
207 /*
208 * Set registers for trampoline to user mode. Leave space for the
209 * return address on stack. These are the kernel mode register values.
210 */
211 pcb2->pcb_r12 = (register_t)fork_return; /* fork_trampoline argument */
212 pcb2->pcb_rbp = 0;
213 pcb2->pcb_rsp = (register_t)td2->td_frame - sizeof(void *);
214 pcb2->pcb_rbx = (register_t)td2; /* fork_trampoline argument */
215 pcb2->pcb_rip = (register_t)fork_trampoline;
216 /*-
217 * pcb2->pcb_dr*: cloned above.
218 * pcb2->pcb_savefpu: cloned above.
219 * pcb2->pcb_flags: cloned above.
220 * pcb2->pcb_onfault: cloned above (always NULL here?).
221 * pcb2->pcb_[fg]sbase: cloned above
222 */
223
224 /* Setup to release spin count in fork_exit(). */
225 td2->td_md.md_spinlock_count = 1;
226 td2->td_md.md_saved_flags = PSL_KERNEL | PSL_I;
227 td2->td_md.md_invl_gen.gen = 0;
228
229 /* As an i386, do not copy io permission bitmap. */
230 pcb2->pcb_tssp = NULL;
231
232 /* New segment registers. */
233 set_pcb_flags_raw(pcb2, PCB_FULL_IRET);
234
235 /* Copy the LDT, if necessary. */
236 mdp1 = &td1->td_proc->p_md;
237 mdp2 = &p2->p_md;
238 mtx_lock(&dt_lock);
239 if (mdp1->md_ldt != NULL) {
240 if (flags & RFMEM) {
241 mdp1->md_ldt->ldt_refcnt++;
242 mdp2->md_ldt = mdp1->md_ldt;
243 bcopy(&mdp1->md_ldt_sd, &mdp2->md_ldt_sd, sizeof(struct
244 system_segment_descriptor));
245 } else {
246 mdp2->md_ldt = NULL;
247 mdp2->md_ldt = user_ldt_alloc(p2, 0);
248 if (mdp2->md_ldt == NULL)
249 panic("could not copy LDT");
250 amd64_set_ldt_data(td2, 0, max_ldt_segment,
251 (struct user_segment_descriptor *)
252 mdp1->md_ldt->ldt_base);
253 }
254 } else
255 mdp2->md_ldt = NULL;
256 mtx_unlock(&dt_lock);
257
258 /*
259 * Now, cpu_switch() can schedule the new process.
260 * pcb_rsp is loaded pointing to the cpu_switch() stack frame
261 * containing the return address when exiting cpu_switch.
262 * This will normally be to fork_trampoline(), which will have
263 * %ebx loaded with the new proc's pointer. fork_trampoline()
264 * will set up a stack to call fork_return(p, frame); to complete
265 * the return to user-mode.
266 */
267 }
268
269 /*
270 * Intercept the return address from a freshly forked process that has NOT
271 * been scheduled yet.
272 *
273 * This is needed to make kernel threads stay in kernel mode.
274 */
275 void
cpu_fork_kthread_handler(struct thread * td,void (* func)(void *),void * arg)276 cpu_fork_kthread_handler(struct thread *td, void (*func)(void *), void *arg)
277 {
278 /*
279 * Note that the trap frame follows the args, so the function
280 * is really called like this: func(arg, frame);
281 */
282 td->td_pcb->pcb_r12 = (long) func; /* function */
283 td->td_pcb->pcb_rbx = (long) arg; /* first arg */
284 }
285
286 void
cpu_exit(struct thread * td)287 cpu_exit(struct thread *td)
288 {
289
290 /*
291 * If this process has a custom LDT, release it.
292 */
293 mtx_lock(&dt_lock);
294 if (td->td_proc->p_md.md_ldt != 0)
295 user_ldt_free(td);
296 else
297 mtx_unlock(&dt_lock);
298 }
299
300 void
cpu_thread_exit(struct thread * td)301 cpu_thread_exit(struct thread *td)
302 {
303 struct pcb *pcb;
304
305 critical_enter();
306 if (td == PCPU_GET(fpcurthread))
307 fpudrop();
308 critical_exit();
309
310 pcb = td->td_pcb;
311
312 /* Disable any hardware breakpoints. */
313 if (pcb->pcb_flags & PCB_DBREGS) {
314 reset_dbregs();
315 clear_pcb_flags(pcb, PCB_DBREGS);
316 }
317 }
318
319 void
cpu_thread_clean(struct thread * td)320 cpu_thread_clean(struct thread *td)
321 {
322 struct pcb *pcb;
323
324 pcb = td->td_pcb;
325
326 /*
327 * Clean TSS/iomap
328 */
329 if (pcb->pcb_tssp != NULL) {
330 pmap_pti_remove_kva((vm_offset_t)pcb->pcb_tssp,
331 (vm_offset_t)pcb->pcb_tssp + ctob(IOPAGES + 1));
332 kmem_free(kernel_arena, (vm_offset_t)pcb->pcb_tssp,
333 ctob(IOPAGES + 1));
334 pcb->pcb_tssp = NULL;
335 }
336 }
337
338 void
cpu_thread_swapin(struct thread * td)339 cpu_thread_swapin(struct thread *td)
340 {
341 }
342
343 void
cpu_thread_swapout(struct thread * td)344 cpu_thread_swapout(struct thread *td)
345 {
346 }
347
348 void
cpu_thread_alloc(struct thread * td)349 cpu_thread_alloc(struct thread *td)
350 {
351 struct pcb *pcb;
352 struct xstate_hdr *xhdr;
353
354 td->td_pcb = pcb = get_pcb_td(td);
355 td->td_frame = (struct trapframe *)pcb - 1;
356 pcb->pcb_save = get_pcb_user_save_pcb(pcb);
357 if (use_xsave) {
358 xhdr = (struct xstate_hdr *)(pcb->pcb_save + 1);
359 bzero(xhdr, sizeof(*xhdr));
360 xhdr->xstate_bv = xsave_mask;
361 }
362 }
363
364 void
cpu_thread_free(struct thread * td)365 cpu_thread_free(struct thread *td)
366 {
367
368 cpu_thread_clean(td);
369 }
370
371 void
cpu_set_syscall_retval(struct thread * td,int error)372 cpu_set_syscall_retval(struct thread *td, int error)
373 {
374
375 switch (error) {
376 case 0:
377 td->td_frame->tf_rax = td->td_retval[0];
378 td->td_frame->tf_rdx = td->td_retval[1];
379 td->td_frame->tf_rflags &= ~PSL_C;
380 break;
381
382 case ERESTART:
383 /*
384 * Reconstruct pc, we know that 'syscall' is 2 bytes,
385 * lcall $X,y is 7 bytes, int 0x80 is 2 bytes.
386 * We saved this in tf_err.
387 * %r10 (which was holding the value of %rcx) is restored
388 * for the next iteration.
389 * %r10 restore is only required for freebsd/amd64 processes,
390 * but shall be innocent for any ia32 ABI.
391 *
392 * Require full context restore to get the arguments
393 * in the registers reloaded at return to usermode.
394 */
395 td->td_frame->tf_rip -= td->td_frame->tf_err;
396 td->td_frame->tf_r10 = td->td_frame->tf_rcx;
397 set_pcb_flags(td->td_pcb, PCB_FULL_IRET);
398 break;
399
400 case EJUSTRETURN:
401 break;
402
403 default:
404 td->td_frame->tf_rax = SV_ABI_ERRNO(td->td_proc, error);
405 td->td_frame->tf_rflags |= PSL_C;
406 break;
407 }
408 }
409
410 /*
411 * Initialize machine state, mostly pcb and trap frame for a new
412 * thread, about to return to userspace. Put enough state in the new
413 * thread's PCB to get it to go back to the fork_return(), which
414 * finalizes the thread state and handles peculiarities of the first
415 * return to userspace for the new thread.
416 */
417 void
cpu_copy_thread(struct thread * td,struct thread * td0)418 cpu_copy_thread(struct thread *td, struct thread *td0)
419 {
420 struct pcb *pcb2;
421
422 /* Point the pcb to the top of the stack. */
423 pcb2 = td->td_pcb;
424
425 /*
426 * Copy the upcall pcb. This loads kernel regs.
427 * Those not loaded individually below get their default
428 * values here.
429 */
430 update_pcb_bases(td0->td_pcb);
431 bcopy(td0->td_pcb, pcb2, sizeof(*pcb2));
432 clear_pcb_flags(pcb2, PCB_FPUINITDONE | PCB_USERFPUINITDONE |
433 PCB_KERNFPU);
434 pcb2->pcb_save = get_pcb_user_save_pcb(pcb2);
435 bcopy(get_pcb_user_save_td(td0), pcb2->pcb_save,
436 cpu_max_ext_state_size);
437 set_pcb_flags_raw(pcb2, PCB_FULL_IRET);
438
439 /*
440 * Create a new fresh stack for the new thread.
441 */
442 bcopy(td0->td_frame, td->td_frame, sizeof(struct trapframe));
443
444 /* If the current thread has the trap bit set (i.e. a debugger had
445 * single stepped the process to the system call), we need to clear
446 * the trap flag from the new frame. Otherwise, the new thread will
447 * receive a (likely unexpected) SIGTRAP when it executes the first
448 * instruction after returning to userland.
449 */
450 td->td_frame->tf_rflags &= ~PSL_T;
451
452 /*
453 * Set registers for trampoline to user mode. Leave space for the
454 * return address on stack. These are the kernel mode register values.
455 */
456 pcb2->pcb_r12 = (register_t)fork_return; /* trampoline arg */
457 pcb2->pcb_rbp = 0;
458 pcb2->pcb_rsp = (register_t)td->td_frame - sizeof(void *); /* trampoline arg */
459 pcb2->pcb_rbx = (register_t)td; /* trampoline arg */
460 pcb2->pcb_rip = (register_t)fork_trampoline;
461 /*
462 * If we didn't copy the pcb, we'd need to do the following registers:
463 * pcb2->pcb_dr*: cloned above.
464 * pcb2->pcb_savefpu: cloned above.
465 * pcb2->pcb_onfault: cloned above (always NULL here?).
466 * pcb2->pcb_[fg]sbase: cloned above
467 */
468
469 /* Setup to release spin count in fork_exit(). */
470 td->td_md.md_spinlock_count = 1;
471 td->td_md.md_saved_flags = PSL_KERNEL | PSL_I;
472 }
473
474 /*
475 * Set that machine state for performing an upcall that starts
476 * the entry function with the given argument.
477 */
478 void
cpu_set_upcall(struct thread * td,void (* entry)(void *),void * arg,stack_t * stack)479 cpu_set_upcall(struct thread *td, void (*entry)(void *), void *arg,
480 stack_t *stack)
481 {
482
483 /*
484 * Do any extra cleaning that needs to be done.
485 * The thread may have optional components
486 * that are not present in a fresh thread.
487 * This may be a recycled thread so make it look
488 * as though it's newly allocated.
489 */
490 cpu_thread_clean(td);
491
492 #ifdef COMPAT_FREEBSD32
493 if (SV_PROC_FLAG(td->td_proc, SV_ILP32)) {
494 /*
495 * Set the trap frame to point at the beginning of the entry
496 * function.
497 */
498 td->td_frame->tf_rbp = 0;
499 td->td_frame->tf_rsp =
500 (((uintptr_t)stack->ss_sp + stack->ss_size - 4) & ~0x0f) - 4;
501 td->td_frame->tf_rip = (uintptr_t)entry;
502
503 /* Return address sentinel value to stop stack unwinding. */
504 suword32((void *)td->td_frame->tf_rsp, 0);
505
506 /* Pass the argument to the entry point. */
507 suword32((void *)(td->td_frame->tf_rsp + sizeof(int32_t)),
508 (uint32_t)(uintptr_t)arg);
509
510 return;
511 }
512 #endif
513
514 /*
515 * Set the trap frame to point at the beginning of the uts
516 * function.
517 */
518 td->td_frame->tf_rbp = 0;
519 td->td_frame->tf_rsp =
520 ((register_t)stack->ss_sp + stack->ss_size) & ~0x0f;
521 td->td_frame->tf_rsp -= 8;
522 td->td_frame->tf_rip = (register_t)entry;
523 td->td_frame->tf_ds = _udatasel;
524 td->td_frame->tf_es = _udatasel;
525 td->td_frame->tf_fs = _ufssel;
526 td->td_frame->tf_gs = _ugssel;
527 td->td_frame->tf_flags = TF_HASSEGS;
528
529 /* Return address sentinel value to stop stack unwinding. */
530 suword((void *)td->td_frame->tf_rsp, 0);
531
532 /* Pass the argument to the entry point. */
533 td->td_frame->tf_rdi = (register_t)arg;
534 }
535
536 int
cpu_set_user_tls(struct thread * td,void * tls_base)537 cpu_set_user_tls(struct thread *td, void *tls_base)
538 {
539 struct pcb *pcb;
540
541 if ((u_int64_t)tls_base >= VM_MAXUSER_ADDRESS)
542 return (EINVAL);
543
544 pcb = td->td_pcb;
545 set_pcb_flags(pcb, PCB_FULL_IRET);
546 #ifdef COMPAT_FREEBSD32
547 if (SV_PROC_FLAG(td->td_proc, SV_ILP32)) {
548 pcb->pcb_gsbase = (register_t)tls_base;
549 return (0);
550 }
551 #endif
552 pcb->pcb_fsbase = (register_t)tls_base;
553 return (0);
554 }
555
556 /*
557 * Software interrupt handler for queued VM system processing.
558 */
559 void
swi_vm(void * dummy)560 swi_vm(void *dummy)
561 {
562 if (busdma_swi_pending != 0)
563 busdma_swi();
564 }
565
566 /*
567 * Tell whether this address is in some physical memory region.
568 * Currently used by the kernel coredump code in order to avoid
569 * dumping the ``ISA memory hole'' which could cause indefinite hangs,
570 * or other unpredictable behaviour.
571 */
572
573 int
is_physical_memory(vm_paddr_t addr)574 is_physical_memory(vm_paddr_t addr)
575 {
576
577 #ifdef DEV_ISA
578 /* The ISA ``memory hole''. */
579 if (addr >= 0xa0000 && addr < 0x100000)
580 return 0;
581 #endif
582
583 /*
584 * stuff other tests for known memory-mapped devices (PCI?)
585 * here
586 */
587
588 return 1;
589 }
590