1 /* $OpenBSD: vm_machdep.c,v 1.74 2023/04/11 00:45:07 jsg Exp $ */
2 /* $NetBSD: vm_machdep.c,v 1.61 1996/05/03 19:42:35 christos Exp $ */
3
4 /*-
5 * Copyright (c) 1995 Charles M. Hannum. All rights reserved.
6 * Copyright (c) 1982, 1986 The Regents of the University of California.
7 * Copyright (c) 1989, 1990 William Jolitz
8 * All rights reserved.
9 *
10 * This code is derived from software contributed to Berkeley by
11 * the Systems Programming Group of the University of Utah Computer
12 * Science Department, and William Jolitz.
13 *
14 * Redistribution and use in source and binary forms, with or without
15 * modification, are permitted provided that the following conditions
16 * are met:
17 * 1. Redistributions of source code must retain the above copyright
18 * notice, this list of conditions and the following disclaimer.
19 * 2. Redistributions in binary form must reproduce the above copyright
20 * notice, this list of conditions and the following disclaimer in the
21 * documentation and/or other materials provided with the distribution.
22 * 3. Neither the name of the University nor the names of its contributors
23 * may be used to endorse or promote products derived from this software
24 * without specific prior written permission.
25 *
26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
36 * SUCH DAMAGE.
37 *
38 * @(#)vm_machdep.c 7.3 (Berkeley) 5/13/91
39 */
40
41 /*
42 * Utah $Hdr: vm_machdep.c 1.16.1.1 89/06/23$
43 */
44
45 #include <sys/param.h>
46 #include <sys/systm.h>
47 #include <sys/proc.h>
48 #include <sys/buf.h>
49 #include <sys/user.h>
50
51 #include <uvm/uvm_extern.h>
52
53 #include "npx.h"
54
55 /*
56 * Finish a fork operation, with process p2 nearly set up.
57 * Copy and update the kernel stack and pcb, making the child
58 * ready to run, and marking it so that it can return differently
59 * than the parent. Returns 1 in the child process, 0 in the parent.
60 */
61 void
cpu_fork(struct proc * p1,struct proc * p2,void * stack,void * tcb,void (* func)(void *),void * arg)62 cpu_fork(struct proc *p1, struct proc *p2, void *stack, void *tcb,
63 void (*func)(void *), void *arg)
64 {
65 struct pcb *pcb = &p2->p_addr->u_pcb;
66 struct trapframe *tf;
67 struct switchframe *sf;
68
69 #if NNPX > 0
70 npxsave_proc(p1, 1);
71 #endif
72
73 p2->p_md.md_flags = p1->p_md.md_flags;
74
75 #ifdef DIAGNOSTIC
76 if (p1 != curproc && p1 != &proc0)
77 panic("cpu_fork: curproc");
78 #endif
79 *pcb = p1->p_addr->u_pcb;
80
81 pcb->pcb_kstack = (int)p2->p_addr + USPACE - 16 -
82 (arc4random() & PAGE_MASK & ~_STACKALIGNBYTES);
83
84 /*
85 * Copy the trapframe, and arrange for the child to return directly
86 */
87 p2->p_md.md_regs = tf = (struct trapframe *)pcb->pcb_kstack - 1;
88 *tf = *p1->p_md.md_regs;
89
90 /*
91 * If specified, give the child a different stack and/or TCB
92 */
93 if (stack != NULL)
94 tf->tf_esp = (u_int)stack;
95 if (tcb != NULL)
96 i386_set_threadbase(p2, (uint32_t)tcb, TSEG_GS);
97
98 sf = (struct switchframe *)tf - 1;
99 sf->sf_esi = (int)func;
100 sf->sf_ebx = (int)arg;
101 sf->sf_eip = (int)proc_trampoline;
102 pcb->pcb_esp = (int)sf;
103 pcb->pcb_ebp = 0;
104 }
105
106 /*
107 * cpu_exit is called as the last action during exit.
108 */
109 void
cpu_exit(struct proc * p)110 cpu_exit(struct proc *p)
111 {
112 #if NNPX > 0
113 /* If we were using the FPU, forget about it. */
114 if (p->p_addr->u_pcb.pcb_fpcpu != NULL)
115 npxsave_proc(p, 0);
116 #endif
117 sched_exit(p);
118 }
119
120 /*
121 * Convert kernel VA to physical address
122 */
123 int
kvtop(caddr_t addr)124 kvtop(caddr_t addr)
125 {
126 paddr_t pa;
127
128 if (pmap_extract(pmap_kernel(), (vaddr_t)addr, &pa) == FALSE)
129 panic("kvtop: zero page frame");
130 return((int)pa);
131 }
132
133 struct kmem_va_mode kv_physwait = {
134 .kv_map = &phys_map,
135 .kv_wait = 1,
136 };
137
138 /*
139 * Map a user I/O request into kernel virtual address space.
140 * Note: the pages are already locked by uvm_vslock(), so we
141 * do not need to pass an access_type to pmap_enter().
142 */
143 void
vmapbuf(struct buf * bp,vsize_t len)144 vmapbuf(struct buf *bp, vsize_t len)
145 {
146 vaddr_t faddr, taddr, off;
147 paddr_t fpa;
148
149 if ((bp->b_flags & B_PHYS) == 0)
150 panic("vmapbuf");
151 faddr = trunc_page((vaddr_t)(bp->b_saveaddr = bp->b_data));
152 off = (vaddr_t)bp->b_data - faddr;
153 len = round_page(off + len);
154 taddr = (vaddr_t)km_alloc(len, &kv_physwait, &kp_none, &kd_waitok);
155 bp->b_data = (caddr_t)(taddr + off);
156 /*
157 * The region is locked, so we expect that pmap_pte() will return
158 * non-NULL.
159 * XXX: unwise to expect this in a multithreaded environment.
160 * anything can happen to a pmap between the time we lock a
161 * region, release the pmap lock, and then relock it for
162 * the pmap_extract().
163 *
164 * no need to flush TLB since we expect nothing to be mapped
165 * where we just allocated (TLB will be flushed when our
166 * mapping is removed).
167 */
168 while (len) {
169 (void) pmap_extract(vm_map_pmap(&bp->b_proc->p_vmspace->vm_map),
170 faddr, &fpa);
171 pmap_kenter_pa(taddr, fpa, PROT_READ | PROT_WRITE);
172 faddr += PAGE_SIZE;
173 taddr += PAGE_SIZE;
174 len -= PAGE_SIZE;
175 }
176 pmap_update(pmap_kernel());
177 }
178
179 /*
180 * Unmap a previously-mapped user I/O request.
181 */
182 void
vunmapbuf(struct buf * bp,vsize_t len)183 vunmapbuf(struct buf *bp, vsize_t len)
184 {
185 vaddr_t addr, off;
186
187 if ((bp->b_flags & B_PHYS) == 0)
188 panic("vunmapbuf");
189 addr = trunc_page((vaddr_t)bp->b_data);
190 off = (vaddr_t)bp->b_data - addr;
191 len = round_page(off + len);
192 pmap_kremove(addr, len);
193 pmap_update(pmap_kernel());
194 km_free((void *)addr, len, &kv_physwait, &kp_none);
195 bp->b_data = bp->b_saveaddr;
196 bp->b_saveaddr = NULL;
197 }
198