1 /****************************************************************************
2 *
3 * Realmode X86 Emulator Library
4 *
5 * Copyright (C) 1991-2004 SciTech Software, Inc.
6 * Copyright (C) David Mosberger-Tang
7 * Copyright (C) 1999 Egbert Eich
8 *
9 * ========================================================================
10 *
11 * Permission to use, copy, modify, distribute, and sell this software and
12 * its documentation for any purpose is hereby granted without fee,
13 * provided that the above copyright notice appear in all copies and that
14 * both that copyright notice and this permission notice appear in
15 * supporting documentation, and that the name of the authors not be used
16 * in advertising or publicity pertaining to distribution of the software
17 * without specific, written prior permission. The authors makes no
18 * representations about the suitability of this software for any purpose.
19 * It is provided "as is" without express or implied warranty.
20 *
21 * THE AUTHORS DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
22 * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
23 * EVENT SHALL THE AUTHORS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
24 * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF
25 * USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
26 * OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
27 * PERFORMANCE OF THIS SOFTWARE.
28 *
29 * ========================================================================
30 *
31 * Language: ANSI C
32 * Environment: Any
33 * Developer: Kendall Bennett
34 *
35 * Description: This file contains the code to handle debugging of the
36 * emulator.
37 *
38 ****************************************************************************/
39
40 #include <stdarg.h>
41 #include <common.h>
42 #include <linux/ctype.h>
43 #include "x86emu/x86emui.h"
44
45 /*----------------------------- Implementation ----------------------------*/
46
47 #ifdef CONFIG_X86EMU_DEBUG
48
49 static void print_encoded_bytes(u16 s, u16 o);
50 static void print_decoded_instruction(void);
51 static int x86emu_parse_line(char *s, int *ps, int *n);
52
53 /* should look something like debug's output. */
X86EMU_trace_regs(void)54 void X86EMU_trace_regs(void)
55 {
56 if (DEBUG_TRACE()) {
57 x86emu_dump_regs();
58 }
59 if (DEBUG_DECODE() && !DEBUG_DECODE_NOPRINT()) {
60 printk("%04x:%04x ", M.x86.saved_cs, M.x86.saved_ip);
61 print_encoded_bytes(M.x86.saved_cs, M.x86.saved_ip);
62 print_decoded_instruction();
63 }
64 }
65
X86EMU_trace_xregs(void)66 void X86EMU_trace_xregs(void)
67 {
68 if (DEBUG_TRACE()) {
69 x86emu_dump_xregs();
70 }
71 }
72
x86emu_just_disassemble(void)73 void x86emu_just_disassemble(void)
74 {
75 /*
76 * This routine called if the flag DEBUG_DISASSEMBLE is set kind
77 * of a hack!
78 */
79 printk("%04x:%04x ", M.x86.saved_cs, M.x86.saved_ip);
80 print_encoded_bytes(M.x86.saved_cs, M.x86.saved_ip);
81 print_decoded_instruction();
82 }
83
disassemble_forward(u16 seg,u16 off,int n)84 static void disassemble_forward(u16 seg, u16 off, int n)
85 {
86 X86EMU_sysEnv tregs;
87 int i;
88 u8 op1;
89 /*
90 * hack, hack, hack. What we do is use the exact machinery set up
91 * for execution, except that now there is an additional state
92 * flag associated with the "execution", and we are using a copy
93 * of the register struct. All the major opcodes, once fully
94 * decoded, have the following two steps: TRACE_REGS(r,m);
95 * SINGLE_STEP(r,m); which disappear if DEBUG is not defined to
96 * the preprocessor. The TRACE_REGS macro expands to:
97 *
98 * if (debug&DEBUG_DISASSEMBLE)
99 * {just_disassemble(); goto EndOfInstruction;}
100 * if (debug&DEBUG_TRACE) trace_regs(r,m);
101 *
102 * ...... and at the last line of the routine.
103 *
104 * EndOfInstruction: end_instr();
105 *
106 * Up to the point where TRACE_REG is expanded, NO modifications
107 * are done to any register EXCEPT the IP register, for fetch and
108 * decoding purposes.
109 *
110 * This was done for an entirely different reason, but makes a
111 * nice way to get the system to help debug codes.
112 */
113 tregs = M;
114 tregs.x86.R_IP = off;
115 tregs.x86.R_CS = seg;
116
117 /* reset the decoding buffers */
118 tregs.x86.enc_str_pos = 0;
119 tregs.x86.enc_pos = 0;
120
121 /* turn on the "disassemble only, no execute" flag */
122 tregs.x86.debug |= DEBUG_DISASSEMBLE_F;
123
124 /* DUMP NEXT n instructions to screen in straight_line fashion */
125 /*
126 * This looks like the regular instruction fetch stream, except
127 * that when this occurs, each fetched opcode, upon seeing the
128 * DEBUG_DISASSEMBLE flag set, exits immediately after decoding
129 * the instruction. XXX --- CHECK THAT MEM IS NOT AFFECTED!!!
130 * Note the use of a copy of the register structure...
131 */
132 for (i = 0; i < n; i++) {
133 op1 = (*sys_rdb) (((u32) M.x86.R_CS << 4) + (M.x86.R_IP++));
134 (x86emu_optab[op1]) (op1);
135 }
136 /* end major hack mode. */
137 }
138
x86emu_check_ip_access(void)139 void x86emu_check_ip_access(void)
140 {
141 /* NULL as of now */
142 }
143
x86emu_check_sp_access(void)144 void x86emu_check_sp_access(void)
145 {
146 }
147
x86emu_check_mem_access(u32 dummy)148 void x86emu_check_mem_access(u32 dummy)
149 {
150 /* check bounds, etc */
151 }
152
x86emu_check_data_access(uint dummy1,uint dummy2)153 void x86emu_check_data_access(uint dummy1, uint dummy2)
154 {
155 /* check bounds, etc */
156 }
157
x86emu_inc_decoded_inst_len(int x)158 void x86emu_inc_decoded_inst_len(int x)
159 {
160 M.x86.enc_pos += x;
161 }
162
x86emu_decode_printf(char * x)163 void x86emu_decode_printf(char *x)
164 {
165 sprintf(M.x86.decoded_buf + M.x86.enc_str_pos, "%s", x);
166 M.x86.enc_str_pos += strlen(x);
167 }
168
x86emu_decode_printf2(char * x,int y)169 void x86emu_decode_printf2(char *x, int y)
170 {
171 char temp[100];
172 sprintf(temp, x, y);
173 sprintf(M.x86.decoded_buf + M.x86.enc_str_pos, "%s", temp);
174 M.x86.enc_str_pos += strlen(temp);
175 }
176
x86emu_end_instr(void)177 void x86emu_end_instr(void)
178 {
179 M.x86.enc_str_pos = 0;
180 M.x86.enc_pos = 0;
181 }
182
print_encoded_bytes(u16 s,u16 o)183 static void print_encoded_bytes(u16 s, u16 o)
184 {
185 int i;
186 char buf1[64];
187 for (i = 0; i < M.x86.enc_pos; i++) {
188 sprintf(buf1 + 2 * i, "%02x", fetch_data_byte_abs(s, o + i));
189 }
190 printk("%-20s", buf1);
191 }
192
print_decoded_instruction(void)193 static void print_decoded_instruction(void)
194 {
195 printk("%s", M.x86.decoded_buf);
196 }
197
x86emu_print_int_vect(u16 iv)198 void x86emu_print_int_vect(u16 iv)
199 {
200 u16 seg, off;
201
202 if (iv > 256)
203 return;
204 seg = fetch_data_word_abs(0, iv * 4);
205 off = fetch_data_word_abs(0, iv * 4 + 2);
206 printk("%04x:%04x ", seg, off);
207 }
208
X86EMU_dump_memory(u16 seg,u16 off,u32 amt)209 void X86EMU_dump_memory(u16 seg, u16 off, u32 amt)
210 {
211 u32 start = off & 0xfffffff0;
212 u32 end = (off + 16) & 0xfffffff0;
213 u32 i;
214
215 while (end <= off + amt) {
216 printk("%04x:%04x ", seg, start);
217 for (i = start; i < off; i++)
218 printk(" ");
219 for (; i < end; i++)
220 printk("%02x ", fetch_data_byte_abs(seg, i));
221 printk("\n");
222 start = end;
223 end = start + 16;
224 }
225 }
226
x86emu_single_step(void)227 void x86emu_single_step(void)
228 {
229 char s[1024];
230 int ps[10];
231 int ntok;
232 int cmd;
233 int done;
234 int segment;
235 int offset;
236 static int breakpoint;
237 static int noDecode = 1;
238
239 if (DEBUG_BREAK()) {
240 if (M.x86.saved_ip != breakpoint) {
241 return;
242 } else {
243 M.x86.debug &= ~DEBUG_DECODE_NOPRINT_F;
244 M.x86.debug |= DEBUG_TRACE_F;
245 M.x86.debug &= ~DEBUG_BREAK_F;
246 print_decoded_instruction();
247 X86EMU_trace_regs();
248 }
249 }
250 done = 0;
251 offset = M.x86.saved_ip;
252 while (!done) {
253 printk("-");
254 ps[1] = 0; /* Avoid dodgy compiler warnings */
255 ps[2] = 0;
256 cmd = x86emu_parse_line(s, ps, &ntok);
257 switch (cmd) {
258 case 'u':
259 disassemble_forward(M.x86.saved_cs, (u16) offset, 10);
260 break;
261 case 'd':
262 if (ntok == 2) {
263 segment = M.x86.saved_cs;
264 offset = ps[1];
265 X86EMU_dump_memory(segment, (u16) offset, 16);
266 offset += 16;
267 } else if (ntok == 3) {
268 segment = ps[1];
269 offset = ps[2];
270 X86EMU_dump_memory(segment, (u16) offset, 16);
271 offset += 16;
272 } else {
273 segment = M.x86.saved_cs;
274 X86EMU_dump_memory(segment, (u16) offset, 16);
275 offset += 16;
276 }
277 break;
278 case 'c':
279 M.x86.debug ^= DEBUG_TRACECALL_F;
280 break;
281 case 's':
282 M.x86.debug ^=
283 DEBUG_SVC_F | DEBUG_SYS_F | DEBUG_SYSINT_F;
284 break;
285 case 'r':
286 X86EMU_trace_regs();
287 break;
288 case 'x':
289 X86EMU_trace_xregs();
290 break;
291 case 'g':
292 if (ntok == 2) {
293 breakpoint = ps[1];
294 if (noDecode) {
295 M.x86.debug |= DEBUG_DECODE_NOPRINT_F;
296 } else {
297 M.x86.debug &= ~DEBUG_DECODE_NOPRINT_F;
298 }
299 M.x86.debug &= ~DEBUG_TRACE_F;
300 M.x86.debug |= DEBUG_BREAK_F;
301 done = 1;
302 }
303 break;
304 case 'q':
305 M.x86.debug |= DEBUG_EXIT;
306 return;
307 case 'P':
308 noDecode = (noDecode) ? 0 : 1;
309 printk("Toggled decoding to %s\n",
310 (noDecode) ? "false" : "true");
311 break;
312 case 't':
313 case 0:
314 done = 1;
315 break;
316 }
317 }
318 }
319
X86EMU_trace_on(void)320 int X86EMU_trace_on(void)
321 {
322 return M.x86.debug |= DEBUG_STEP_F | DEBUG_DECODE_F | DEBUG_TRACE_F;
323 }
324
X86EMU_trace_off(void)325 int X86EMU_trace_off(void)
326 {
327 return M.x86.debug &= ~(DEBUG_STEP_F | DEBUG_DECODE_F | DEBUG_TRACE_F);
328 }
329
x86emu_parse_line(char * s,int * ps,int * n)330 static int x86emu_parse_line(char *s, int *ps, int *n)
331 {
332 int cmd;
333
334 *n = 0;
335 while (isblank(*s))
336 s++;
337 ps[*n] = *s;
338 switch (*s) {
339 case '\n':
340 *n += 1;
341 return 0;
342 default:
343 cmd = *s;
344 *n += 1;
345 }
346
347 while (1) {
348 while (!isblank(*s) && *s != '\n')
349 s++;
350
351 if (*s == '\n')
352 return cmd;
353
354 while (isblank(*s))
355 s++;
356
357 *n += 1;
358 }
359 }
360
361 #endif /* DEBUG */
362
x86emu_dump_regs(void)363 void x86emu_dump_regs(void)
364 {
365 printk("\tAX=%04x ", M.x86.R_AX);
366 printk("BX=%04x ", M.x86.R_BX);
367 printk("CX=%04x ", M.x86.R_CX);
368 printk("DX=%04x ", M.x86.R_DX);
369 printk("SP=%04x ", M.x86.R_SP);
370 printk("BP=%04x ", M.x86.R_BP);
371 printk("SI=%04x ", M.x86.R_SI);
372 printk("DI=%04x\n", M.x86.R_DI);
373 printk("\tDS=%04x ", M.x86.R_DS);
374 printk("ES=%04x ", M.x86.R_ES);
375 printk("SS=%04x ", M.x86.R_SS);
376 printk("CS=%04x ", M.x86.R_CS);
377 printk("IP=%04x ", M.x86.R_IP);
378 if (ACCESS_FLAG(F_OF))
379 printk("OV "); /* CHECKED... */
380 else
381 printk("NV ");
382 if (ACCESS_FLAG(F_DF))
383 printk("DN ");
384 else
385 printk("UP ");
386 if (ACCESS_FLAG(F_IF))
387 printk("EI ");
388 else
389 printk("DI ");
390 if (ACCESS_FLAG(F_SF))
391 printk("NG ");
392 else
393 printk("PL ");
394 if (ACCESS_FLAG(F_ZF))
395 printk("ZR ");
396 else
397 printk("NZ ");
398 if (ACCESS_FLAG(F_AF))
399 printk("AC ");
400 else
401 printk("NA ");
402 if (ACCESS_FLAG(F_PF))
403 printk("PE ");
404 else
405 printk("PO ");
406 if (ACCESS_FLAG(F_CF))
407 printk("CY ");
408 else
409 printk("NC ");
410 printk("\n");
411 }
412
x86emu_dump_xregs(void)413 void x86emu_dump_xregs(void)
414 {
415 printk("\tEAX=%08x ", M.x86.R_EAX);
416 printk("EBX=%08x ", M.x86.R_EBX);
417 printk("ECX=%08x ", M.x86.R_ECX);
418 printk("EDX=%08x \n", M.x86.R_EDX);
419 printk("\tESP=%08x ", M.x86.R_ESP);
420 printk("EBP=%08x ", M.x86.R_EBP);
421 printk("ESI=%08x ", M.x86.R_ESI);
422 printk("EDI=%08x\n", M.x86.R_EDI);
423 printk("\tDS=%04x ", M.x86.R_DS);
424 printk("ES=%04x ", M.x86.R_ES);
425 printk("SS=%04x ", M.x86.R_SS);
426 printk("CS=%04x ", M.x86.R_CS);
427 printk("EIP=%08x\n\t", M.x86.R_EIP);
428 if (ACCESS_FLAG(F_OF))
429 printk("OV "); /* CHECKED... */
430 else
431 printk("NV ");
432 if (ACCESS_FLAG(F_DF))
433 printk("DN ");
434 else
435 printk("UP ");
436 if (ACCESS_FLAG(F_IF))
437 printk("EI ");
438 else
439 printk("DI ");
440 if (ACCESS_FLAG(F_SF))
441 printk("NG ");
442 else
443 printk("PL ");
444 if (ACCESS_FLAG(F_ZF))
445 printk("ZR ");
446 else
447 printk("NZ ");
448 if (ACCESS_FLAG(F_AF))
449 printk("AC ");
450 else
451 printk("NA ");
452 if (ACCESS_FLAG(F_PF))
453 printk("PE ");
454 else
455 printk("PO ");
456 if (ACCESS_FLAG(F_CF))
457 printk("CY ");
458 else
459 printk("NC ");
460 printk("\n");
461 }
462