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
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.
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
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.
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
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 * $FreeBSD: src/sys/i386/i386/vm_machdep.c,v 1.132.2.9 2003/01/25 19:02:23 dillon Exp $
42 * $DragonFly: src/sys/platform/vkernel/i386/vm_machdep.c,v 1.10 2008/08/02 05:22:21 dillon Exp $
48 #include <sys/param.h>
49 #include <sys/systm.h>
50 #include <sys/malloc.h>
53 #include <sys/interrupt.h>
54 #include <sys/vnode.h>
55 #include <sys/vmmeter.h>
56 #include <sys/kernel.h>
57 #include <sys/sysctl.h>
58 #include <sys/unistd.h>
60 #include <machine/clock.h>
61 #include <machine/cpu.h>
62 #include <machine/md_var.h>
63 #include <machine/smp.h>
64 #include <machine/pcb.h>
65 #include <machine/pcb_ext.h>
66 #include <machine/vm86.h>
67 #include <machine/segments.h>
68 #include <machine/globaldata.h> /* npxthread */
71 #include <vm/vm_param.h>
73 #include <vm/vm_kern.h>
74 #include <vm/vm_page.h>
75 #include <vm/vm_map.h>
76 #include <vm/vm_extern.h>
79 #include <sys/thread2.h>
81 #include <bus/isa/isa.h>
86 char machine
[] = MACHINE
;
87 SYSCTL_STRING(_hw
, HW_MACHINE
, machine
, CTLFLAG_RD
,
88 machine
, 0, "Machine class");
90 char cpu_vendor
[] = "DragonFly"; /* XXX */
91 u_int cpu_id
= 0x80000000; /* XXX */
94 * Finish a fork operation, with lwp lp2 nearly set up.
95 * Copy and update the pcb, set up the stack so that the child
96 * ready to run and return to user mode.
99 cpu_fork(struct lwp
*lp1
, struct lwp
*lp2
, int flags
)
103 if ((flags
& RFPROC
) == 0) {
104 if ((flags
& RFMEM
) == 0) {
105 /* unshare user LDT */
106 struct pcb
*pcb1
= lp1
->lwp_thread
->td_pcb
;
107 struct pcb_ldt
*pcb_ldt
= pcb1
->pcb_ldt
;
108 if (pcb_ldt
&& pcb_ldt
->ldt_refcnt
> 1) {
109 pcb_ldt
= user_ldt_alloc(pcb1
,pcb_ldt
->ldt_len
);
111 pcb1
->pcb_ldt
= pcb_ldt
;
119 /* Ensure that lp1's pcb is up to date. */
120 if (mdcpu
->gd_npxthread
== lp1
->lwp_thread
)
121 npxsave(lp1
->lwp_thread
->td_savefpu
);
125 * Copy lp1's PCB. This really only applies to the
126 * debug registers and FP state, but its faster to just copy the
127 * whole thing. Because we only save the PCB at switchout time,
128 * the register state may not be current.
130 pcb2
= lp2
->lwp_thread
->td_pcb
;
131 *pcb2
= *lp1
->lwp_thread
->td_pcb
;
134 * Create a new fresh stack for the new process.
135 * Copy the trap frame for the return to user mode as if from a
136 * syscall. This copies the user mode register values. The
137 * 16 byte offset saves space for vm86, and must match
138 * common_tss.esp0 (kernel stack pointer on entry from user mode)
140 * pcb_esp must allocate an additional call-return pointer below
141 * the trap frame which will be restored by cpu_restore from
142 * PCB_EIP, and the thread's td_sp pointer must allocate an
143 * additonal two worsd below the pcb_esp call-return pointer to
144 * hold the LWKT restore function pointer and eflags.
146 * The LWKT restore function pointer must be set to cpu_restore,
147 * which is our standard heavy weight process switch-in function.
148 * YYY eventually we should shortcut fork_return and fork_trampoline
149 * to use the LWKT restore function directly so we can get rid of
150 * all the extra crap we are setting up.
152 lp2
->lwp_md
.md_regs
= (struct trapframe
*)((char *)pcb2
- 16) - 1;
153 bcopy(lp1
->lwp_md
.md_regs
, lp2
->lwp_md
.md_regs
, sizeof(*lp2
->lwp_md
.md_regs
));
156 * Set registers for trampoline to user mode. Leave space for the
157 * return address on stack. These are the kernel mode register values.
159 pcb2
->pcb_unused01
= 0;
161 pcb2
->pcb_esi
= (int)fork_return
; /* fork_trampoline argument */
163 pcb2
->pcb_esp
= (int)lp2
->lwp_md
.md_regs
- sizeof(void *);
164 pcb2
->pcb_ebx
= (int)lp2
; /* fork_trampoline argument */
165 pcb2
->pcb_eip
= (int)fork_trampoline
;
166 lp2
->lwp_thread
->td_sp
= (char *)(pcb2
->pcb_esp
- sizeof(void *));
167 *(u_int32_t
*)lp2
->lwp_thread
->td_sp
= PSL_USER
;
168 lp2
->lwp_thread
->td_sp
-= sizeof(void *);
169 *(void **)lp2
->lwp_thread
->td_sp
= (void *)cpu_heavy_restore
;
172 * pcb2->pcb_ldt: duplicated below, if necessary.
173 * pcb2->pcb_savefpu: cloned above.
174 * pcb2->pcb_flags: cloned above (always 0 here?).
175 * pcb2->pcb_onfault: cloned above (always NULL here?).
179 * XXX don't copy the i/o pages. this should probably be fixed.
183 /* Copy the LDT, if necessary. */
184 if (pcb2
->pcb_ldt
!= 0) {
186 pcb2
->pcb_ldt
->ldt_refcnt
++;
188 pcb2
->pcb_ldt
= user_ldt_alloc(pcb2
,
189 pcb2
->pcb_ldt
->ldt_len
);
192 bcopy(&lp1
->lwp_thread
->td_tls
, &lp2
->lwp_thread
->td_tls
,
193 sizeof(lp2
->lwp_thread
->td_tls
));
195 * Now, cpu_switch() can schedule the new process.
196 * pcb_esp is loaded pointing to the cpu_switch() stack frame
197 * containing the return address when exiting cpu_switch.
198 * This will normally be to fork_trampoline(), which will have
199 * %ebx loaded with the new proc's pointer. fork_trampoline()
200 * will set up a stack to call fork_return(p, frame); to complete
201 * the return to user-mode.
206 * Prepare new lwp to return to the address specified in params.
209 cpu_prepare_lwp(struct lwp
*lp
, struct lwp_params
*params
)
211 struct trapframe
*regs
= lp
->lwp_md
.md_regs
;
212 void *bad_return
= NULL
;
215 regs
->tf_eip
= (int)params
->func
;
216 regs
->tf_esp
= (int)params
->stack
;
217 /* Set up argument for function call */
218 regs
->tf_esp
-= sizeof(params
->arg
);
219 error
= copyout(¶ms
->arg
, (void *)regs
->tf_esp
,
220 sizeof(params
->arg
));
224 * Set up fake return address. As the lwp function may never return,
225 * we simply copy out a NULL pointer and force the lwp to receive
226 * a SIGSEGV if it returns anyways.
228 regs
->tf_esp
-= sizeof(void *);
229 error
= copyout(&bad_return
, (void *)regs
->tf_esp
,
234 cpu_set_fork_handler(lp
,
235 (void (*)(void *, struct trapframe
*))generic_lwp_return
, lp
);
240 * Intercept the return address from a freshly forked process that has NOT
241 * been scheduled yet.
243 * This is needed to make kernel threads stay in kernel mode.
246 cpu_set_fork_handler(struct lwp
*lp
, void (*func
)(void *, struct trapframe
*),
250 * Note that the trap frame follows the args, so the function
251 * is really called like this: func(arg, frame);
253 lp
->lwp_thread
->td_pcb
->pcb_esi
= (int) func
; /* function */
254 lp
->lwp_thread
->td_pcb
->pcb_ebx
= (int) arg
; /* first arg */
258 cpu_set_thread_handler(thread_t td
, void (*rfunc
)(void), void *func
, void *arg
)
260 td
->td_pcb
->pcb_esi
= (int)func
;
261 td
->td_pcb
->pcb_ebx
= (int) arg
;
262 td
->td_switch
= cpu_lwkt_switch
;
263 td
->td_sp
-= sizeof(void *);
264 *(void **)td
->td_sp
= rfunc
; /* exit function on return */
265 td
->td_sp
-= sizeof(void *);
266 *(void **)td
->td_sp
= cpu_kthread_restore
;
272 struct thread
*td
= curthread
;
281 * If we were using a private TSS do a forced-switch to ourselves
282 * to switch back to the common TSS before freeing it.
285 if ((ext
= pcb
->pcb_ext
) != NULL
) {
290 kmem_free(&kernel_map
, (vm_offset_t
)ext
, ctob(IOPAGES
+ 1));
293 if (pcb
->pcb_flags
& PCB_DBREGS
) {
295 * disable all hardware breakpoints
298 pcb
->pcb_flags
&= ~PCB_DBREGS
;
300 td
->td_gd
->gd_cnt
.v_swtch
++;
302 crit_enter_quick(td
);
303 lwkt_deschedule_self(td
);
304 lwkt_remove_tdallq(td
);
309 * Terminate the current thread. The caller must have already acquired
310 * the thread's rwlock and placed it on a reap list or otherwise notified
311 * a reaper of its existance. We set a special assembly switch function which
312 * releases td_rwlock after it has cleaned up the MMU state and switched
315 * Must be caller from a critical section and with the thread descheduled.
318 cpu_thread_exit(void)
320 curthread
->td_switch
= cpu_exit_switch
;
321 curthread
->td_flags
|= TDF_EXITING
;
327 * Process Reaper. Called after the caller has acquired the thread's
328 * rwlock and removed it from the reap list.
331 cpu_proc_wait(struct proc
*p
)
333 /* drop per-process resources */
334 pmap_dispose_proc(p
);
339 setredzone(u_short
*pte
, caddr_t vaddr
)
341 /* eventually do this by setting up an expand-down stack segment
342 for ss0: selector, allowing stack access down to top of u.
343 this means though that protection violations need to be handled
344 thru a double fault exception that must do an integral task
345 switch to a known good context, within which a dump can be
346 taken. a sensible scheme might be to save the initial context
347 used by sched (that has physical memory mapped 1:1 at bottom)
348 and take the dump while still in mapped mode */
353 * Convert kernel VA to physical address
360 pa
= pmap_kextract((vm_offset_t
)addr
);
362 panic("kvtop: zero page frame");
367 grow_stack(struct proc
*p
, u_int sp
)
371 rv
= vm_map_growstack (p
, sp
);
372 if (rv
!= KERN_SUCCESS
)
378 SYSCTL_DECL(_vm_stats_misc
);
380 static int cnt_prezero
;
382 SYSCTL_INT(_vm_stats_misc
, OID_AUTO
,
383 cnt_prezero
, CTLFLAG_RD
, &cnt_prezero
, 0, "");
386 * Tell whether this address is in some physical memory region.
387 * Currently used by the kernel coredump code in order to avoid
388 * dumping the ``ISA memory hole'' which could cause indefinite hangs,
389 * or other unpredictable behaviour.
393 is_physical_memory(vm_offset_t addr
)
399 * Used by /dev/kmem to determine if we can safely read or write
400 * the requested KVA range. Some portions of kernel memory are
401 * not governed by our virtual page table.
404 extern void _start(void);
407 kvm_access_check(vm_offset_t saddr
, vm_offset_t eaddr
, int prot
)
411 if (saddr
>= (vm_offset_t
)&_start
&& eaddr
<= (vm_offset_t
)&_end
)
413 if (saddr
< KvaStart
)
417 for (addr
= saddr
; addr
< eaddr
; addr
+= PAGE_SIZE
) {
418 if (pmap_extract(&kernel_pmap
, addr
) == 0)
421 if (!kernacc((caddr_t
)saddr
, eaddr
- saddr
, prot
))