xref: /freebsd/lib/libkvm/kvm_i386.c (revision b52f49a9a0f22207ad5130ad8faba08de3ed23d8)
1 /*-
2  * Copyright (c) 1989, 1992, 1993
3  *	The Regents of the University of California.  All rights reserved.
4  *
5  * This code is derived from software developed by the Computer Systems
6  * Engineering group at Lawrence Berkeley Laboratory under DARPA contract
7  * BG 91-66 and contributed to Berkeley.
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that the following conditions
11  * are met:
12  * 1. Redistributions of source code must retain the above copyright
13  *    notice, this list of conditions and the following disclaimer.
14  * 2. Redistributions in binary form must reproduce the above copyright
15  *    notice, this list of conditions and the following disclaimer in the
16  *    documentation and/or other materials provided with the distribution.
17  * 3. All advertising materials mentioning features or use of this software
18  *    must display the following acknowledgement:
19  *	This product includes software developed by the University of
20  *	California, Berkeley and its contributors.
21  * 4. Neither the name of the University nor the names of its contributors
22  *    may be used to endorse or promote products derived from this software
23  *    without specific prior written permission.
24  *
25  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
26  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
27  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
28  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
29  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
30  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
31  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
32  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
33  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
34  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
35  * SUCH DAMAGE.
36  */
37 
38 #include <sys/cdefs.h>
39 __FBSDID("$FreeBSD$");
40 
41 #if defined(LIBC_SCCS) && !defined(lint)
42 #if 0
43 static char sccsid[] = "@(#)kvm_hp300.c	8.1 (Berkeley) 6/4/93";
44 #endif
45 #endif /* LIBC_SCCS and not lint */
46 
47 /*
48  * i386 machine dependent routines for kvm.  Hopefully, the forthcoming
49  * vm code will one day obsolete this module.
50  */
51 
52 #include <sys/param.h>
53 #include <sys/user.h>
54 #include <sys/proc.h>
55 #include <sys/stat.h>
56 #include <stdlib.h>
57 #include <unistd.h>
58 #include <nlist.h>
59 #include <kvm.h>
60 
61 #include <vm/vm.h>
62 #include <vm/vm_param.h>
63 
64 #include <limits.h>
65 
66 #include "kvm_private.h"
67 
68 #ifndef btop
69 #define	btop(x)		(i386_btop(x))
70 #define	ptob(x)		(i386_ptob(x))
71 #endif
72 
73 struct vmstate {
74 	pd_entry_t	*PTD;
75 };
76 
77 void
78 _kvm_freevtop(kvm_t *kd)
79 {
80 	if (kd->vmst != 0) {
81 		if (kd->vmst->PTD) {
82 			free(kd->vmst->PTD);
83 		}
84 		free(kd->vmst);
85 	}
86 }
87 
88 int
89 _kvm_initvtop(kvm_t *kd)
90 {
91 	struct vmstate *vm;
92 	struct nlist nlist[2];
93 	u_long pa;
94 	u_long kernbase;
95 	pd_entry_t	*PTD;
96 
97 	vm = (struct vmstate *)_kvm_malloc(kd, sizeof(*vm));
98 	if (vm == 0) {
99 		_kvm_err(kd, kd->program, "cannot allocate vm");
100 		return (-1);
101 	}
102 	kd->vmst = vm;
103 	vm->PTD = 0;
104 
105 	nlist[0].n_name = "kernbase";
106 	nlist[1].n_name = 0;
107 
108 	if (kvm_nlist(kd, nlist) != 0)
109 		kernbase = KERNBASE;	/* for old kernels */
110 	else
111 		kernbase = nlist[0].n_value;
112 
113 	nlist[0].n_name = "IdlePTD";
114 	nlist[1].n_name = 0;
115 
116 	if (kvm_nlist(kd, nlist) != 0) {
117 		_kvm_err(kd, kd->program, "bad namelist");
118 		return (-1);
119 	}
120 	if (kvm_read(kd, (nlist[0].n_value - kernbase), &pa, sizeof(pa)) !=
121 	    sizeof(pa)) {
122 		_kvm_err(kd, kd->program, "cannot read IdlePTD");
123 		return (-1);
124 	}
125 	PTD = _kvm_malloc(kd, PAGE_SIZE);
126 	if (kvm_read(kd, pa, PTD, PAGE_SIZE) != PAGE_SIZE) {
127 		_kvm_err(kd, kd->program, "cannot read PTD");
128 		return (-1);
129 	}
130 	vm->PTD = PTD;
131 	return (0);
132 }
133 
134 static int
135 _kvm_vatop(kvm_t *kd, u_long va, u_long *pa)
136 {
137 	struct vmstate *vm;
138 	u_long offset;
139 	u_long pte_pa;
140 	pd_entry_t pde;
141 	pt_entry_t pte;
142 	u_long pdeindex;
143 	u_long pteindex;
144 	int i;
145 
146 	if (ISALIVE(kd)) {
147 		_kvm_err(kd, 0, "vatop called in live kernel!");
148 		return((off_t)0);
149 	}
150 
151 	vm = kd->vmst;
152 	offset = va & (PAGE_SIZE - 1);
153 
154 	/*
155 	 * If we are initializing (kernel page table descriptor pointer
156 	 * not yet set) then return pa == va to avoid infinite recursion.
157 	 */
158 	if (vm->PTD == 0) {
159 		*pa = va;
160 		return (PAGE_SIZE - offset);
161 	}
162 
163 	pdeindex = va >> PDRSHIFT;
164 	pde = vm->PTD[pdeindex];
165 	if (((u_long)pde & PG_V) == 0)
166 		goto invalid;
167 
168 	if ((u_long)pde & PG_PS) {
169 	      /*
170 	       * No second-level page table; ptd describes one 4MB page.
171 	       * (We assume that the kernel wouldn't set PG_PS without enabling
172 	       * it cr0, and that the kernel doesn't support 36-bit physical
173 	       * addresses).
174 	       */
175 #define	PAGE4M_MASK	(NBPDR - 1)
176 #define	PG_FRAME4M	(~PAGE4M_MASK)
177 		*pa = ((u_long)pde & PG_FRAME4M) + (va & PAGE4M_MASK);
178 		return (NBPDR - (va & PAGE4M_MASK));
179 	}
180 
181 	pteindex = (va >> PAGE_SHIFT) & (NPTEPG-1);
182 	pte_pa = ((u_long)pde & PG_FRAME) + (pteindex * sizeof(pt_entry_t));
183 
184 	/* XXX This has to be a physical address read, kvm_read is virtual */
185 	if (lseek(kd->pmfd, pte_pa, 0) == -1) {
186 		_kvm_syserr(kd, kd->program, "_kvm_vatop: lseek");
187 		goto invalid;
188 	}
189 	if (read(kd->pmfd, &pte, sizeof pte) != sizeof pte) {
190 		_kvm_syserr(kd, kd->program, "_kvm_vatop: read");
191 		goto invalid;
192 	}
193 	if (((u_long)pte & PG_V) == 0)
194 		goto invalid;
195 
196 	*pa = ((u_long)pte & PG_FRAME) + offset;
197 	return (PAGE_SIZE - offset);
198 
199 invalid:
200 	_kvm_err(kd, 0, "invalid address (%x)", va);
201 	return (0);
202 }
203 
204 int
205 _kvm_kvatop(kvm_t *kd, u_long va, u_long *pa)
206 {
207 	return (_kvm_vatop(kd, va, pa));
208 }
209