Annotation of sys/arch/i386/i386/vm_machdep.c, Revision 1.1.1.1
1.1 nbrk 1: /* $OpenBSD: vm_machdep.c,v 1.52 2007/05/27 20:59:25 miod 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/signalvar.h>
49: #include <sys/malloc.h>
50: #include <sys/vnode.h>
51: #include <sys/buf.h>
52: #include <sys/user.h>
53: #include <sys/core.h>
54: #include <sys/exec.h>
55: #include <sys/ptrace.h>
56:
57: #include <uvm/uvm_extern.h>
58:
59: #include <machine/cpu.h>
60: #include <machine/gdt.h>
61: #include <machine/reg.h>
62: #include <machine/specialreg.h>
63:
64: #include "npx.h"
65:
66: /*
67: * Finish a fork operation, with process p2 nearly set up.
68: * Copy and update the kernel stack and pcb, making the child
69: * ready to run, and marking it so that it can return differently
70: * than the parent. Returns 1 in the child process, 0 in the parent.
71: * We currently double-map the user area so that the stack is at the same
72: * address in each process; in the future we will probably relocate
73: * the frame pointers on the stack after copying.
74: */
75: void
76: cpu_fork(struct proc *p1, struct proc *p2, void *stack, size_t stacksize,
77: void (*func)(void *), void *arg)
78: {
79: struct pcb *pcb = &p2->p_addr->u_pcb;
80: struct trapframe *tf;
81: struct switchframe *sf;
82:
83: #if NNPX > 0
84: npxsave_proc(p1, 1);
85: #endif
86:
87: p2->p_md.md_flags = p1->p_md.md_flags;
88:
89: /* Copy pcb from proc p1 to p2. */
90: if (p1 == curproc) {
91: /* Sync the PCB before we copy it. */
92: savectx(curpcb);
93: }
94: #ifdef DIAGNOSTIC
95: else if (p1 != &proc0)
96: panic("cpu_fork: curproc");
97: #endif
98: *pcb = p1->p_addr->u_pcb;
99:
100: /*
101: * Preset these so that gdt_compact() doesn't get confused if called
102: * during the allocations below.
103: *
104: * Note: pcb_ldt_sel is handled in the pmap_activate() call when
105: * we run the new process.
106: */
107: p2->p_md.md_tss_sel = GSEL(GNULL_SEL, SEL_KPL);
108:
109: /* Fix up the TSS. */
110: pcb->pcb_tss.tss_ss0 = GSEL(GDATA_SEL, SEL_KPL);
111: pcb->pcb_tss.tss_esp0 = (int)p2->p_addr + USPACE - 16;
112:
113: p2->p_md.md_tss_sel = tss_alloc(pcb);
114:
115: /*
116: * Copy the trapframe, and arrange for the child to return directly
117: * through rei().
118: */
119: p2->p_md.md_regs = tf = (struct trapframe *)pcb->pcb_tss.tss_esp0 - 1;
120: *tf = *p1->p_md.md_regs;
121:
122: /*
123: * If specified, give the child a different stack.
124: */
125: if (stack != NULL)
126: tf->tf_esp = (u_int)stack + stacksize;
127:
128: sf = (struct switchframe *)tf - 1;
129: sf->sf_ppl = 0;
130: sf->sf_esi = (int)func;
131: sf->sf_ebx = (int)arg;
132: sf->sf_eip = (int)proc_trampoline;
133: pcb->pcb_esp = (int)sf;
134: }
135:
136: /*
137: * cpu_exit is called as the last action during exit.
138: *
139: * We clean up a little and then call switch_exit() with the old proc as an
140: * argument. switch_exit() first switches to proc0's context, then does the
141: * vmspace_free() and kmem_free() that we don't do here, and finally jumps
142: * into switch() to wait for another process to wake up.
143: */
144: void
145: cpu_exit(struct proc *p)
146: {
147: #if NNPX > 0
148: /* If we were using the FPU, forget about it. */
149: if (p->p_addr->u_pcb.pcb_fpcpu != NULL)
150: npxsave_proc(p, 0);
151: #endif
152:
153: pmap_deactivate(p);
154: switch_exit(p);
155: }
156:
157: void
158: cpu_wait(struct proc *p)
159: {
160: tss_free(p->p_md.md_tss_sel);
161: }
162:
163: /*
164: * Dump the machine specific segment at the start of a core dump.
165: */
166: struct md_core {
167: struct reg intreg;
168: struct fpreg freg;
169: };
170:
171: int
172: cpu_coredump(struct proc *p, struct vnode *vp, struct ucred *cred,
173: struct core *chdr)
174: {
175: struct md_core md_core;
176: struct coreseg cseg;
177: int error;
178:
179: CORE_SETMAGIC(*chdr, COREMAGIC, MID_I386, 0);
180: chdr->c_hdrsize = ALIGN(sizeof(*chdr));
181: chdr->c_seghdrsize = ALIGN(sizeof(cseg));
182: chdr->c_cpusize = sizeof(md_core);
183:
184: /* Save integer registers. */
185: error = process_read_regs(p, &md_core.intreg);
186: if (error)
187: return error;
188:
189: /* Save floating point registers. */
190: error = process_read_fpregs(p, &md_core.freg);
191: if (error)
192: return error;
193:
194: CORE_SETMAGIC(cseg, CORESEGMAGIC, MID_I386, CORE_CPU);
195: cseg.c_addr = 0;
196: cseg.c_size = chdr->c_cpusize;
197:
198: error = vn_rdwr(UIO_WRITE, vp, (caddr_t)&cseg, chdr->c_seghdrsize,
199: (off_t)chdr->c_hdrsize, UIO_SYSSPACE, IO_NODELOCKED|IO_UNIT, cred,
200: NULL, p);
201: if (error)
202: return error;
203:
204: error = vn_rdwr(UIO_WRITE, vp, (caddr_t)&md_core, sizeof(md_core),
205: (off_t)(chdr->c_hdrsize + chdr->c_seghdrsize), UIO_SYSSPACE,
206: IO_NODELOCKED|IO_UNIT, cred, NULL, p);
207: if (error)
208: return error;
209:
210: chdr->c_nseg++;
211: return 0;
212: }
213:
214: /*
215: * Convert kernel VA to physical address
216: */
217: int
218: kvtop(caddr_t addr)
219: {
220: paddr_t pa;
221:
222: if (pmap_extract(pmap_kernel(), (vaddr_t)addr, &pa) == FALSE)
223: panic("kvtop: zero page frame");
224: return((int)pa);
225: }
226:
227: /*
228: * Map an user IO request into kernel virtual address space.
229: */
230: void
231: vmapbuf(struct buf *bp, vsize_t len)
232: {
233: vaddr_t faddr, taddr, off;
234: paddr_t fpa;
235:
236: if ((bp->b_flags & B_PHYS) == 0)
237: panic("vmapbuf");
238: faddr = trunc_page((vaddr_t)(bp->b_saveaddr = bp->b_data));
239: off = (vaddr_t)bp->b_data - faddr;
240: len = round_page(off + len);
241: taddr= uvm_km_valloc_wait(phys_map, len);
242: bp->b_data = (caddr_t)(taddr + off);
243: /*
244: * The region is locked, so we expect that pmap_pte() will return
245: * non-NULL.
246: * XXX: unwise to expect this in a multithreaded environment.
247: * anything can happen to a pmap between the time we lock a
248: * region, release the pmap lock, and then relock it for
249: * the pmap_extract().
250: *
251: * no need to flush TLB since we expect nothing to be mapped
252: * where we we just allocated (TLB will be flushed when our
253: * mapping is removed).
254: */
255: while (len) {
256: pmap_extract(vm_map_pmap(&bp->b_proc->p_vmspace->vm_map),
257: faddr, &fpa);
258: pmap_kenter_pa(taddr, fpa, VM_PROT_READ|VM_PROT_WRITE);
259: faddr += PAGE_SIZE;
260: taddr += PAGE_SIZE;
261: len -= PAGE_SIZE;
262: }
263: pmap_update(pmap_kernel());
264: }
265:
266: /*
267: * Free the io map PTEs associated with this IO operation.
268: * We also invalidate the TLB entries and restore the original b_addr.
269: */
270: void
271: vunmapbuf(struct buf *bp, vsize_t len)
272: {
273: vaddr_t addr, off;
274:
275: if ((bp->b_flags & B_PHYS) == 0)
276: panic("vunmapbuf");
277: addr = trunc_page((vaddr_t)bp->b_data);
278: off = (vaddr_t)bp->b_data - addr;
279: len = round_page(off + len);
280: pmap_kremove(addr, len);
281: pmap_update(pmap_kernel());
282: uvm_km_free_wakeup(phys_map, addr, len);
283: bp->b_data = bp->b_saveaddr;
284: bp->b_saveaddr = 0;
285: }
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