/[gxemul]/trunk/src/memory_x86.c
This is repository of my old source code which isn't updated any more. Go to git.rot13.org for current projects!
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Revision 6 - (hide annotations)
Mon Oct 8 16:18:11 2007 UTC (12 years, 6 months ago) by dpavlin
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File size: 6817 byte(s)
++ trunk/HISTORY	(local)
$Id: HISTORY,v 1.772 2005/06/04 12:02:16 debug Exp $
20050428	Disabling the "-fmove-all-movables" option in the configure
		script, because it causes the compile to fail on OpenBSD/sgi.
20050502	Minor updates.
20050503	Removing the WRT54G mode (it was bogus anyway), and adding a
		comment about Windows NT for MIPS in doc/experiments.html.
		Minor updates to the x86 instruction decoding.
20050504	Adding some more x86 instructions.
		Adding support for reading files from ISO9660 CDROMs (including
		gzipped files). It's an ugly hack, but it seems to work.
		Various other minor updates (dev_vga.c, pc_bios.c etc).
20050505	Some more x86-related updates.
		Beginning (what I hope will be) a major code cleanup phase.
		"bootris" (an x86 bootsector) runs :-)
20050506	Adding some more x86 instructions.
20050507	tmpnam => mkstemp.
		Working on a hack to allow VGA charcells to be shown even when
		not running with X11.
		Adding more x86 instructions.
20050508	x86 32-bit SIB addressing fix, and more instructions.
20050509	Adding more x86 instructions.
20050510	Minor documentation updates, and other updates (x86 stuff etc.)
20050511	More x86-related updates.
20050513	Various updates, mostly x86-related. (Trying to fix flag 
		calculation, factoring out the ugly shift/rotate code, and
		some other things.)
20050514	Adding support for loading some old i386 a.out executables.
		Finally beginning the cleanup of machine/PROM/bios dependant
		info.
		Some minor documentation updates.
		Trying to clean up ARCBIOS stuff a little.
20050515	Trying to make it possible to actually use more than one disk
		type per machine (floppy, ide, scsi).
		Trying to clean up the kbd vs PROM console stuff. (For PC and
		ARC emulation modes, mostly.)
		Beginning to add an 8259 interrupt controller, and connecting
		it to the x86 emulation.
20050516	The first x86 interrupts seem to work (keyboard stuff).
		Adding a 8253/8254 programmable interval timer skeleton.
		FreeDOS now reaches a command prompt and can be interacted
		with.
20050517	After some bugfixes, MS-DOS also (sometimes) reaches a
		command prompt now.
		Trying to fix the pckbc to work with MS-DOS' keyb.com, but no
		success yet.
20050518	Adding a simple 32-bit x86 MMU skeleton.
20050519	Some more work on the x86 stuff. (Beginning the work on paging,
		and various other fixes).
20050520	More updates. Working on dev_vga (4-bit graphics modes), adding
		40 columns support to the PC bios emulation.
		Trying to add support for resizing windows when switching
		between graphics modes.
20050521	Many more x86-related updates.
20050522	Correcting the initial stack pointer's sign-extension for
		ARCBIOS emulation (thanks to Alec Voropay for noticing the
		error).
		Continuing on the cleanup (ARCBIOS etc).
		dev_vga updates.
20050523	More x86 updates: trying to add some support for protected mode
		interrupts (via gate descriptors) and many other fixes.
		More ARCBIOS cleanup.
		Adding a device flag which indicates that reads cause no
		side-effects. (Useful for the "dump" command in the debugger,
		and other things.)
		Adding support for directly starting up x86 ELFs, skipping the
		bootloader stage. (Most ELFs, however, are not suitable for
		this.)
20050524	Adding simple 32-bit x86 TSS task switching, but no privilege
		level support yet.
		More work on dev_vga. A small "Copper bars" demo works. :-)
		Adding support for Trap Flag (single-step exceptions), at least
		in real mode, and various other x86-related fixes.
20050525	Adding a new disk image prefix (gH;S;) which can be used to
		override the default nr of heads and sectors per track.
20050527	Various bug fixes, more work on the x86 mode (stack change on
		interrupts between different priv.levels), and some minor
		documentation updates.
20050528	Various fixes (x86 stuff).
20050529	More x86 fixes. An OpenBSD/i386 bootfloppy reaches userland
		and can be interacted with (although there are problems with
		key repetition). NetBSD/i386 triggers a serious CISC-related
		problem: instruction fetches across page boundaries, where
		the later part isn't actually part of the instruction.
20050530	Various minor updates. (Documentation updates, etc.)
20050531	Adding some experimental code (experiments/new_test_*) which
		could be useful for dynamic (but not binary) translation in
		the future.
20050602	Adding a dummy ARM skeleton.
		Fixing the pckbc key repetition problem (by adding release
		scancodes for all keypresses).
20050603	Minor updates for the next release.
20050604	Release testing. Minor updates.

==============  RELEASE 0.3.3  ==============

20050604	There'll probably be a 0.3.3.1 release soon, with some very
		very tiny updates.


1 dpavlin 6 /*
2     * Copyright (C) 2005 Anders Gavare. All rights reserved.
3     *
4     * Redistribution and use in source and binary forms, with or without
5     * modification, are permitted provided that the following conditions are met:
6     *
7     * 1. Redistributions of source code must retain the above copyright
8     * notice, this list of conditions and the following disclaimer.
9     * 2. Redistributions in binary form must reproduce the above copyright
10     * notice, this list of conditions and the following disclaimer in the
11     * documentation and/or other materials provided with the distribution.
12     * 3. The name of the author may not be used to endorse or promote products
13     * derived from this software without specific prior written permission.
14     *
15     * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16     * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17     * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18     * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19     * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20     * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21     * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22     * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23     * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24     * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25     * SUCH DAMAGE.
26     *
27     *
28     * $Id: memory_x86.c,v 1.18 2005/05/29 10:35:11 debug Exp $
29     *
30     * Included from cpu_x86.c.
31     *
32     *
33     * TODO: This is basically just a skeleton so far.
34     */
35    
36    
37     /*
38     * translate_address():
39     *
40     * Return values:
41     * 0 Failure
42     * 1 Success, the page is readable only
43     * 2 Success, the page is read/write
44     */
45     int TRANSLATE_ADDRESS(struct cpu *cpu, uint64_t vaddr,
46     uint64_t *return_addr, int flags)
47     {
48     unsigned char pded[4];
49     unsigned char pted[4];
50     uint64_t table_addr;
51     uint32_t pte=0, pde=0;
52     int a, b, res, writable, usermode = 0;
53     int writeflag = flags & FLAG_WRITEFLAG? MEM_WRITE : MEM_READ;
54     int no_exceptions = flags & FLAG_NOEXCEPTIONS;
55     int no_segmentation = flags & NO_SEGMENTATION;
56     struct descriptor_cache *dc;
57    
58     if (cpu->cd.x86.cursegment < 0 || cpu->cd.x86.cursegment >= 8) {
59     fatal("TODO: Weird x86 segment nr %i\n",
60     cpu->cd.x86.cursegment);
61     cpu->running = 0;
62     return 0;
63     }
64    
65     if ((vaddr >> 32) == 0xffffffff)
66     vaddr &= 0xffffffff;
67    
68     dc = &cpu->cd.x86.descr_cache[cpu->cd.x86.cursegment & 7];
69    
70     if (no_segmentation) {
71     /* linear address */
72     writable = 1;
73     } else {
74     if (PROTECTED_MODE && vaddr > dc->limit) {
75     fatal("TODO: vaddr=0x%llx > limit (0x%llx)\n",
76     (long long)vaddr, (long long)dc->limit);
77     /* goto fail; */
78     }
79    
80     /* TODO: Check the Privilege Level */
81     vaddr = (vaddr + dc->base) & 0xffffffff;
82     writable = dc->writable;
83     }
84    
85     usermode = (cpu->cd.x86.s[X86_S_CS] & X86_PL_MASK) ==
86     X86_RING3;
87    
88     /* Paging: */
89     if (cpu->cd.x86.cr[0] & X86_CR0_PG) {
90     /* TODO: This should be cached somewhere, in some
91     kind of simulated TLB. */
92     if (cpu->cd.x86.cr[3] & 0xfff) {
93     fatal("TODO: cr3=%016llx (lowest bits non-zero)\n",
94     (long long)cpu->cd.x86.cr[3]);
95     goto fail;
96     }
97    
98     a = (vaddr >> 22) & 1023;
99     b = (vaddr >> 12) & 1023;
100     /* fatal("vaddr = 0x%08x ==> %i, %i\n", (int)vaddr, a, b); */
101    
102     /* Read the Page Directory Entry: */
103     table_addr = cpu->cd.x86.cr[3] & ~0xfff;
104     if (table_addr == 0)
105     fatal("WARNING: The page directory (cr3) is at"
106     " physical address 0 (?)\n");
107     res = cpu->memory_rw(cpu, cpu->mem, table_addr + 4*a, pded,
108     sizeof(pded), MEM_READ, PHYSICAL);
109     if (!res) {
110     fatal("TODO: could not read pde (table = 0x%llx)\n",
111     (long long)table_addr);
112     goto fail;
113     }
114     if ((pded[0] & 0x01) && !(pded[0] & 0x20)) {
115     pded[0] |= 0x20;
116     cpu->memory_rw(cpu, cpu->mem, table_addr + 4*a, pded,
117     sizeof(pded), MEM_WRITE, PHYSICAL);
118     }
119     if ((pded[0] & 0x01) && writeflag == MEM_WRITE &&
120     !(pded[0] & 0x40)) {
121     pded[0] |= 0x40;
122     cpu->memory_rw(cpu, cpu->mem, table_addr + 4*a, pded,
123     sizeof(pded), MEM_WRITE, PHYSICAL);
124     }
125     pde = pded[0] + (pded[1] << 8) + (pded[2] << 16) +
126     (pded[3] << 24);
127     /* fatal(" pde: 0x%08x\n", (int)pde); */
128     /* TODO: lowest bits of the pde */
129     if (!(pde & 0x01)) {
130     fatal("PAGE FAULT: pde not present: vaddr=0x%08x, "
131     "usermode=%i\n", (int)vaddr, usermode);
132     fatal(" CS:EIP = 0x%04x:0x%016llx\n",
133     (int)cpu->cd.x86.s[X86_S_CS],
134     (long long)cpu->pc);
135     if (!no_exceptions) {
136     cpu->cd.x86.cr[2] = vaddr;
137     x86_interrupt(cpu, 14, (writeflag? 2 : 0) +
138     (usermode? 4 : 0));
139     }
140     return 0;
141     }
142    
143     /* Read the Page Table Entry: */
144     table_addr = pde & ~0xfff;
145     res = cpu->memory_rw(cpu, cpu->mem, table_addr + 4*b, pted,
146     sizeof(pted), MEM_READ, PHYSICAL);
147     if (!res) {
148     fatal("TODO: could not read pte (pt = 0x%llx)\n",
149     (long long)table_addr);
150     goto fail;
151     }
152     pte = pted[0] + (pted[1] << 8) + (pted[2] << 16) +
153     (pted[3] << 24);
154     if ((pted[0] & 0x01) && !(pted[0] & 0x20)) {
155     pted[0] |= 0x20;
156     cpu->memory_rw(cpu, cpu->mem, table_addr + 4*b, pted,
157     sizeof(pted), MEM_WRITE, PHYSICAL);
158     }
159     if ((pted[0] & 0x01) && writeflag == MEM_WRITE &&
160     !(pted[0] & 0x40)) {
161     pted[0] |= 0x40;
162     cpu->memory_rw(cpu, cpu->mem, table_addr + 4*b, pted,
163     sizeof(pted), MEM_WRITE, PHYSICAL);
164     }
165     /* fatal(" pte: 0x%08x\n", (int)pte); */
166     if (!(pte & 0x02))
167     writable = 0;
168     if (!(pte & 0x01)) {
169     fatal("TODO: pte not present: table_addr=0x%08x "
170     "vaddr=0x%08x, usermode=%i wf=%i pte=0x%08x\n",
171     (int)table_addr, (int)vaddr, usermode, writeflag,
172     (int)pte);
173     if (!no_exceptions) {
174     cpu->cd.x86.cr[2] = vaddr;
175     x86_interrupt(cpu, 14, (writeflag? 2 : 0)
176     + (usermode? 4 : 0));
177     }
178     return 0;
179     }
180    
181     (*return_addr) = (pte & ~0xfff) | (vaddr & 0xfff);
182     } else
183     *return_addr = vaddr;
184    
185     /* Code: */
186     if (flags & FLAG_INSTR) {
187     if (dc->descr_type == DESCR_TYPE_CODE)
188     return 1;
189     fatal("TODO instr load but not code descriptor?\n");
190     goto fail;
191     }
192    
193     /* We are here on non-instruction fetch. */
194    
195     if (writeflag == MEM_WRITE && !writable) {
196     if (!usermode && !(cpu->cd.x86.cr[0] & X86_CR0_WP)) {
197     /* 80386 compatiblity: allow writes to userspace,
198     if we are running in kernel mode. */
199     writable = 1;
200     } else {
201     fatal("TODO: write to nonwritable segment or page: "
202     "vaddr=0x%08x pde=0x%08x pte=0x%08x\n",
203     (int)vaddr, (int)pde, (int)pte);
204     cpu->cd.x86.cr[2] = vaddr;
205     x86_interrupt(cpu, 14, (writeflag? 2 : 0)
206     + (usermode? 4 : 0) + 1);
207     return 0;
208     }
209     }
210    
211     return 1 + writable;
212    
213     fail:
214     fatal("memory_x86 FAIL: TODO\n");
215     cpu->running = 0;
216     return 0;
217     }
218    

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