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 * Copyright (c) 2008 The DragonFly Project.
8 * This code is derived from software contributed to Berkeley by
9 * the Systems Programming Group of the University of Utah Computer
10 * Science Department, and William Jolitz.
12 * Redistribution and use in source and binary forms, with or without
13 * modification, are permitted provided that the following conditions
15 * 1. Redistributions of source code must retain the above copyright
16 * notice, this list of conditions and the following disclaimer.
17 * 2. Redistributions in binary form must reproduce the above copyright
18 * notice, this list of conditions and the following disclaimer in the
19 * documentation and/or other materials provided with the distribution.
20 * 3. All advertising materials mentioning features or use of this software
21 * must display the following acknowledgement:
22 * This product includes software developed by the University of
23 * California, Berkeley and its contributors.
24 * 4. Neither the name of the University nor the names of its contributors
25 * may be used to endorse or promote products derived from this software
26 * without specific prior written permission.
28 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
29 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
30 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
31 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
32 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
33 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
34 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
35 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
36 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
37 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
40 * from: @(#)vm_machdep.c 7.3 (Berkeley) 5/13/91
41 * Utah $Hdr: vm_machdep.c 1.16.1.1 89/06/23$
42 * $FreeBSD: src/sys/i386/i386/vm_machdep.c,v 1.132.2.9 2003/01/25 19:02:23 dillon Exp $
45 #include <sys/param.h>
46 #include <sys/systm.h>
47 #include <sys/malloc.h>
50 #include <sys/interrupt.h>
51 #include <sys/vnode.h>
52 #include <sys/vmmeter.h>
53 #include <sys/kernel.h>
54 #include <sys/sysctl.h>
55 #include <sys/unistd.h>
57 #include <machine/clock.h>
58 #include <machine/cpu.h>
59 #include <machine/md_var.h>
60 #include <machine/smp.h>
61 #include <machine/pcb.h>
62 #include <machine/pcb_ext.h>
63 #include <machine/segments.h>
64 #include <machine/globaldata.h> /* npxthread */
67 #include <vm/vm_param.h>
69 #include <vm/vm_kern.h>
70 #include <vm/vm_page.h>
71 #include <vm/vm_map.h>
72 #include <vm/vm_extern.h>
74 #include <sys/thread2.h>
76 #include <bus/isa/isa.h>
78 char machine[] = MACHINE;
79 SYSCTL_STRING(_hw, HW_MACHINE, machine, CTLFLAG_RD,
80 machine, 0, "Machine class");
83 * Finish a fork operation, with lwp lp2 nearly set up.
84 * Copy and update the pcb, set up the stack so that the child
85 * ready to run and return to user mode.
88 cpu_fork(struct lwp *lp1, struct lwp *lp2, int flags)
92 if ((flags & RFPROC) == 0) {
93 if ((flags & RFMEM) == 0) {
94 /* unshare user LDT */
95 struct pcb *pcb1 = lp1->lwp_thread->td_pcb;
96 struct pcb_ldt *pcb_ldt = pcb1->pcb_ldt;
97 if (pcb_ldt && pcb_ldt->ldt_refcnt > 1) {
98 pcb_ldt = user_ldt_alloc(pcb1,pcb_ldt->ldt_len);
100 pcb1->pcb_ldt = pcb_ldt;
107 /* Ensure that lp1's pcb is up to date. */
108 if (mdcpu->gd_npxthread == lp1->lwp_thread)
109 npxsave(lp1->lwp_thread->td_savefpu);
112 * Copy lp1's PCB. This really only applies to the
113 * debug registers and FP state, but its faster to just copy the
114 * whole thing. Because we only save the PCB at switchout time,
115 * the register state may not be current.
117 pcb2 = lp2->lwp_thread->td_pcb;
118 *pcb2 = *lp1->lwp_thread->td_pcb;
121 * Create a new fresh stack for the new process.
122 * Copy the trap frame for the return to user mode as if from a
123 * syscall. This copies the user mode register values.
125 * pcb_rsp must allocate an additional call-return pointer below
126 * the trap frame which will be restored by cpu_heavy_restore from
127 * PCB_RIP, and the thread's td_sp pointer must allocate an
128 * additonal two quadwords below the pcb_rsp call-return pointer to
129 * hold the LWKT restore function pointer and rflags.
131 * The LWKT restore function pointer must be set to cpu_heavy_restore,
132 * which is our standard heavy-weight process switch-in function.
133 * YYY eventually we should shortcut fork_return and fork_trampoline
134 * to use the LWKT restore function directly so we can get rid of
135 * all the extra crap we are setting up.
137 lp2->lwp_md.md_regs = (struct trapframe *)pcb2 - 1;
138 bcopy(lp1->lwp_md.md_regs, lp2->lwp_md.md_regs, sizeof(*lp2->lwp_md.md_regs));
141 * Set registers for trampoline to user mode. Leave space for the
142 * return address on stack. These are the kernel mode register values.
144 pcb2->pcb_unused01 = 0;
145 pcb2->pcb_rbx = (unsigned long)fork_return; /* fork_trampoline argument */
147 pcb2->pcb_rsp = (unsigned long)lp2->lwp_md.md_regs - sizeof(void *);
148 pcb2->pcb_r12 = (unsigned long)lp2; /* fork_trampoline argument */
152 pcb2->pcb_rip = (unsigned long)fork_trampoline;
153 lp2->lwp_thread->td_sp = (char *)(pcb2->pcb_rsp - sizeof(void *));
154 *(u_int64_t *)lp2->lwp_thread->td_sp = PSL_USER;
155 lp2->lwp_thread->td_sp -= sizeof(void *);
156 *(void **)lp2->lwp_thread->td_sp = (void *)cpu_heavy_restore;
159 * pcb2->pcb_ldt: duplicated below, if necessary.
160 * pcb2->pcb_savefpu: cloned above.
161 * pcb2->pcb_flags: cloned above (always 0 here?).
162 * pcb2->pcb_onfault: cloned above (always NULL here?).
166 * XXX don't copy the i/o pages. this should probably be fixed.
168 pcb2->pcb_ext = NULL;
170 /* Copy the LDT, if necessary. */
171 if (pcb2->pcb_ldt != NULL) {
173 pcb2->pcb_ldt->ldt_refcnt++;
175 pcb2->pcb_ldt = user_ldt_alloc(pcb2,
176 pcb2->pcb_ldt->ldt_len);
179 bcopy(&lp1->lwp_thread->td_tls, &lp2->lwp_thread->td_tls,
180 sizeof(lp2->lwp_thread->td_tls));
182 * Now, cpu_switch() can schedule the new lwp.
183 * pcb_rsp is loaded pointing to the cpu_switch() stack frame
184 * containing the return address when exiting cpu_switch.
185 * This will normally be to fork_trampoline(), which will have
186 * %rbx loaded with the new lwp's pointer. fork_trampoline()
187 * will set up a stack to call fork_return(lp, frame); to complete
188 * the return to user-mode.
193 * Prepare new lwp to return to the address specified in params.
196 cpu_prepare_lwp(struct lwp *lp, struct lwp_params *params)
198 struct trapframe *regs = lp->lwp_md.md_regs;
199 void *bad_return = NULL;
202 regs->tf_rip = (long)params->func;
203 regs->tf_rsp = (long)params->stack;
204 /* Set up argument for function call */
205 regs->tf_rdi = (long)params->arg; /* JG Can this be in userspace addresses? */
207 * Set up fake return address. As the lwp function may never return,
208 * we simply copy out a NULL pointer and force the lwp to receive
209 * a SIGSEGV if it returns anyways.
211 regs->tf_rsp -= sizeof(void *);
212 error = copyout(&bad_return, (void *)regs->tf_rsp, sizeof(bad_return));
216 cpu_set_fork_handler(lp,
217 (void (*)(void *, struct trapframe *))generic_lwp_return, lp);
222 * Intercept the return address from a freshly forked process that has NOT
223 * been scheduled yet.
225 * This is needed to make kernel threads stay in kernel mode.
228 cpu_set_fork_handler(struct lwp *lp, void (*func)(void *, struct trapframe *),
232 * Note that the trap frame follows the args, so the function
233 * is really called like this: func(arg, frame);
235 lp->lwp_thread->td_pcb->pcb_rbx = (long)func; /* function */
236 lp->lwp_thread->td_pcb->pcb_r12 = (long)arg; /* first arg */
240 cpu_set_thread_handler(thread_t td, void (*rfunc)(void), void *func, void *arg)
242 td->td_pcb->pcb_rbx = (long)func;
243 td->td_pcb->pcb_r12 = (long)arg;
244 td->td_switch = cpu_lwkt_switch;
245 td->td_sp -= sizeof(void *);
246 *(void **)td->td_sp = rfunc; /* exit function on return */
247 td->td_sp -= sizeof(void *);
248 *(void **)td->td_sp = cpu_kthread_restore;
254 struct thread *td = curthread;
259 /* Some i386 functionality was dropped */
260 KKASSERT(pcb->pcb_ext == NULL);
263 * disable all hardware breakpoints
265 if (pcb->pcb_flags & PCB_DBREGS) {
267 pcb->pcb_flags &= ~PCB_DBREGS;
269 td->td_gd->gd_cnt.v_swtch++;
271 crit_enter_quick(td);
272 if (td->td_flags & TDF_TSLEEPQ)
274 lwkt_deschedule_self(td);
275 lwkt_remove_tdallq(td);
280 * Terminate the current thread. The caller must have already acquired
281 * the thread's rwlock and placed it on a reap list or otherwise notified
282 * a reaper of its existance. We set a special assembly switch function which
283 * releases td_rwlock after it has cleaned up the MMU state and switched
286 * Must be caller from a critical section and with the thread descheduled.
289 cpu_thread_exit(void)
292 curthread->td_switch = cpu_exit_switch;
293 curthread->td_flags |= TDF_EXITING;
295 panic("cpu_thread_exit: lwkt_switch() unexpectedly returned");
299 grow_stack(struct proc *p, u_long sp)
303 rv = vm_map_growstack (p, sp);
304 if (rv != KERN_SUCCESS)
311 * Used by /dev/kmem to determine if we can safely read or write
312 * the requested KVA range. Some portions of kernel memory are
313 * not governed by our virtual page table.
316 extern void _start(void);
319 kvm_access_check(vm_offset_t saddr, vm_offset_t eaddr, int prot)
323 if (saddr >= trunc_page((vm_offset_t)&_start) && eaddr <= round_page((vm_offset_t)&_end))
325 if (saddr < KvaStart)
329 for (addr = saddr; addr < eaddr; addr += PAGE_SIZE) {
330 if (pmap_extract(&kernel_pmap, addr) == 0)
333 if (!kernacc((caddr_t)saddr, eaddr - saddr, prot))