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 <linux/printk.h>
44#include "x86emu/x86emui.h"
45
46/*----------------------------- Implementation ----------------------------*/
47
48#ifdef CONFIG_X86EMU_DEBUG
49
50static void print_encoded_bytes(u16 s, u16 o);
51static void print_decoded_instruction(void);
52static int x86emu_parse_line(char *s, int *ps, int *n);
53
54/* should look something like debug's output. */
55void X86EMU_trace_regs(void)
56{
57	if (DEBUG_TRACE()) {
58		x86emu_dump_regs();
59	}
60	if (DEBUG_DECODE() && !DEBUG_DECODE_NOPRINT()) {
61		printk("%04x:%04x ", M.x86.saved_cs, M.x86.saved_ip);
62		print_encoded_bytes(M.x86.saved_cs, M.x86.saved_ip);
63		print_decoded_instruction();
64	}
65}
66
67void X86EMU_trace_xregs(void)
68{
69	if (DEBUG_TRACE()) {
70		x86emu_dump_xregs();
71	}
72}
73
74void x86emu_just_disassemble(void)
75{
76	/*
77	 * This routine called if the flag DEBUG_DISASSEMBLE is set kind
78	 * of a hack!
79	 */
80	printk("%04x:%04x ", M.x86.saved_cs, M.x86.saved_ip);
81	print_encoded_bytes(M.x86.saved_cs, M.x86.saved_ip);
82	print_decoded_instruction();
83}
84
85static void disassemble_forward(u16 seg, u16 off, int n)
86{
87	X86EMU_sysEnv tregs;
88	int i;
89	u8 op1;
90	/*
91	 * hack, hack, hack.  What we do is use the exact machinery set up
92	 * for execution, except that now there is an additional state
93	 * flag associated with the "execution", and we are using a copy
94	 * of the register struct.  All the major opcodes, once fully
95	 * decoded, have the following two steps: TRACE_REGS(r,m);
96	 * SINGLE_STEP(r,m); which disappear if DEBUG is not defined to
97	 * the preprocessor.  The TRACE_REGS macro expands to:
98	 *
99	 * if (debug&DEBUG_DISASSEMBLE)
100	 *     {just_disassemble(); goto EndOfInstruction;}
101	 *     if (debug&DEBUG_TRACE) trace_regs(r,m);
102	 *
103	 * ......  and at the last line of the routine.
104	 *
105	 * EndOfInstruction: end_instr();
106	 *
107	 * Up to the point where TRACE_REG is expanded, NO modifications
108	 * are done to any register EXCEPT the IP register, for fetch and
109	 * decoding purposes.
110	 *
111	 * This was done for an entirely different reason, but makes a
112	 * nice way to get the system to help debug codes.
113	 */
114	tregs = M;
115	tregs.x86.R_IP = off;
116	tregs.x86.R_CS = seg;
117
118	/* reset the decoding buffers */
119	tregs.x86.enc_str_pos = 0;
120	tregs.x86.enc_pos = 0;
121
122	/* turn on the "disassemble only, no execute" flag */
123	tregs.x86.debug |= DEBUG_DISASSEMBLE_F;
124
125	/* DUMP NEXT n instructions to screen in straight_line fashion */
126	/*
127	 * This looks like the regular instruction fetch stream, except
128	 * that when this occurs, each fetched opcode, upon seeing the
129	 * DEBUG_DISASSEMBLE flag set, exits immediately after decoding
130	 * the instruction.  XXX --- CHECK THAT MEM IS NOT AFFECTED!!!
131	 * Note the use of a copy of the register structure...
132	 */
133	for (i = 0; i < n; i++) {
134		op1 = (*sys_rdb) (((u32) M.x86.R_CS << 4) + (M.x86.R_IP++));
135		(x86emu_optab[op1]) (op1);
136	}
137	/* end major hack mode. */
138}
139
140void x86emu_check_ip_access(void)
141{
142	/* NULL as of now */
143}
144
145void x86emu_check_sp_access(void)
146{
147}
148
149void x86emu_check_mem_access(u32 dummy)
150{
151	/*  check bounds, etc */
152}
153
154void x86emu_check_data_access(uint dummy1, uint dummy2)
155{
156	/*  check bounds, etc */
157}
158
159void x86emu_inc_decoded_inst_len(int x)
160{
161	M.x86.enc_pos += x;
162}
163
164void x86emu_decode_printf(char *x)
165{
166	sprintf(M.x86.decoded_buf + M.x86.enc_str_pos, "%s", x);
167	M.x86.enc_str_pos += strlen(x);
168}
169
170void x86emu_decode_printf2(char *x, int y)
171{
172	char temp[100];
173	sprintf(temp, x, y);
174	sprintf(M.x86.decoded_buf + M.x86.enc_str_pos, "%s", temp);
175	M.x86.enc_str_pos += strlen(temp);
176}
177
178void x86emu_end_instr(void)
179{
180	M.x86.enc_str_pos = 0;
181	M.x86.enc_pos = 0;
182}
183
184static void print_encoded_bytes(u16 s, u16 o)
185{
186	int i;
187	char buf1[64];
188	for (i = 0; i < M.x86.enc_pos; i++) {
189		sprintf(buf1 + 2 * i, "%02x", fetch_data_byte_abs(s, o + i));
190	}
191	printk("%-20s", buf1);
192}
193
194static void print_decoded_instruction(void)
195{
196	printk("%s", M.x86.decoded_buf);
197}
198
199void x86emu_print_int_vect(u16 iv)
200{
201	u16 seg, off;
202
203	if (iv > 256)
204		return;
205	seg = fetch_data_word_abs(0, iv * 4);
206	off = fetch_data_word_abs(0, iv * 4 + 2);
207	printk("%04x:%04x ", seg, off);
208}
209
210void X86EMU_dump_memory(u16 seg, u16 off, u32 amt)
211{
212	u32 start = off & 0xfffffff0;
213	u32 end = (off + 16) & 0xfffffff0;
214	u32 i;
215
216	while (end <= off + amt) {
217		printk("%04x:%04x ", seg, start);
218		for (i = start; i < off; i++)
219			printk("   ");
220		for (; i < end; i++)
221			printk("%02x ", fetch_data_byte_abs(seg, i));
222		printk("\n");
223		start = end;
224		end = start + 16;
225	}
226}
227
228void x86emu_single_step(void)
229{
230	char s[1024];
231	 int ps[10];
232	int ntok;
233	int cmd;
234	int done;
235	int segment;
236	int offset;
237	static int breakpoint;
238	static int noDecode = 1;
239
240	if (DEBUG_BREAK()) {
241		if (M.x86.saved_ip != breakpoint) {
242			return;
243		} else {
244			M.x86.debug &= ~DEBUG_DECODE_NOPRINT_F;
245			M.x86.debug |= DEBUG_TRACE_F;
246			M.x86.debug &= ~DEBUG_BREAK_F;
247			print_decoded_instruction();
248			X86EMU_trace_regs();
249		}
250	}
251	done = 0;
252	offset = M.x86.saved_ip;
253	while (!done) {
254		printk("-");
255		ps[1] = 0; /* Avoid dodgy compiler warnings */
256		ps[2] = 0;
257		cmd = x86emu_parse_line(s, ps, &ntok);
258		switch (cmd) {
259		case 'u':
260			disassemble_forward(M.x86.saved_cs, (u16) offset, 10);
261			break;
262		case 'd':
263			if (ntok == 2) {
264				segment = M.x86.saved_cs;
265				offset = ps[1];
266				X86EMU_dump_memory(segment, (u16) offset, 16);
267				offset += 16;
268			} else if (ntok == 3) {
269				segment = ps[1];
270				offset = ps[2];
271				X86EMU_dump_memory(segment, (u16) offset, 16);
272				offset += 16;
273			} else {
274				segment = M.x86.saved_cs;
275				X86EMU_dump_memory(segment, (u16) offset, 16);
276				offset += 16;
277			}
278			break;
279		case 'c':
280			M.x86.debug ^= DEBUG_TRACECALL_F;
281			break;
282		case 's':
283			M.x86.debug ^=
284			    DEBUG_SVC_F | DEBUG_SYS_F | DEBUG_SYSINT_F;
285			break;
286		case 'r':
287			X86EMU_trace_regs();
288			break;
289		case 'x':
290			X86EMU_trace_xregs();
291			break;
292		case 'g':
293			if (ntok == 2) {
294				breakpoint = ps[1];
295				if (noDecode) {
296					M.x86.debug |= DEBUG_DECODE_NOPRINT_F;
297				} else {
298					M.x86.debug &= ~DEBUG_DECODE_NOPRINT_F;
299				}
300				M.x86.debug &= ~DEBUG_TRACE_F;
301				M.x86.debug |= DEBUG_BREAK_F;
302				done = 1;
303			}
304			break;
305		case 'q':
306			M.x86.debug |= DEBUG_EXIT;
307			return;
308		case 'P':
309			noDecode = (noDecode) ? 0 : 1;
310			printk("Toggled decoding to %s\n",
311			       (noDecode) ? "false" : "true");
312			break;
313		case 't':
314		case 0:
315			done = 1;
316			break;
317		}
318	}
319}
320
321int X86EMU_trace_on(void)
322{
323	return M.x86.debug |= DEBUG_STEP_F | DEBUG_DECODE_F | DEBUG_TRACE_F;
324}
325
326int X86EMU_trace_off(void)
327{
328	return M.x86.debug &= ~(DEBUG_STEP_F | DEBUG_DECODE_F | DEBUG_TRACE_F);
329}
330
331static int x86emu_parse_line(char *s, int *ps, int *n)
332{
333	int cmd;
334
335	*n = 0;
336	while (isblank(*s))
337		s++;
338	ps[*n] = *s;
339	switch (*s) {
340	case '\n':
341		*n += 1;
342		return 0;
343	default:
344		cmd = *s;
345		*n += 1;
346	}
347
348	while (1) {
349		while (!isblank(*s) && *s != '\n')
350			s++;
351
352		if (*s == '\n')
353			return cmd;
354
355		while (isblank(*s))
356			s++;
357
358		*n += 1;
359	}
360}
361
362#endif				/* DEBUG */
363
364void x86emu_dump_regs(void)
365{
366	printk("\tAX=%04x  ", M.x86.R_AX);
367	printk("BX=%04x  ", M.x86.R_BX);
368	printk("CX=%04x  ", M.x86.R_CX);
369	printk("DX=%04x  ", M.x86.R_DX);
370	printk("SP=%04x  ", M.x86.R_SP);
371	printk("BP=%04x  ", M.x86.R_BP);
372	printk("SI=%04x  ", M.x86.R_SI);
373	printk("DI=%04x\n", M.x86.R_DI);
374	printk("\tDS=%04x  ", M.x86.R_DS);
375	printk("ES=%04x  ", M.x86.R_ES);
376	printk("SS=%04x  ", M.x86.R_SS);
377	printk("CS=%04x  ", M.x86.R_CS);
378	printk("IP=%04x   ", M.x86.R_IP);
379	if (ACCESS_FLAG(F_OF))
380		printk("OV ");	/* CHECKED... */
381	else
382		printk("NV ");
383	if (ACCESS_FLAG(F_DF))
384		printk("DN ");
385	else
386		printk("UP ");
387	if (ACCESS_FLAG(F_IF))
388		printk("EI ");
389	else
390		printk("DI ");
391	if (ACCESS_FLAG(F_SF))
392		printk("NG ");
393	else
394		printk("PL ");
395	if (ACCESS_FLAG(F_ZF))
396		printk("ZR ");
397	else
398		printk("NZ ");
399	if (ACCESS_FLAG(F_AF))
400		printk("AC ");
401	else
402		printk("NA ");
403	if (ACCESS_FLAG(F_PF))
404		printk("PE ");
405	else
406		printk("PO ");
407	if (ACCESS_FLAG(F_CF))
408		printk("CY ");
409	else
410		printk("NC ");
411	printk("\n");
412}
413
414void x86emu_dump_xregs(void)
415{
416	printk("\tEAX=%08x  ", M.x86.R_EAX);
417	printk("EBX=%08x  ", M.x86.R_EBX);
418	printk("ECX=%08x  ", M.x86.R_ECX);
419	printk("EDX=%08x  \n", M.x86.R_EDX);
420	printk("\tESP=%08x  ", M.x86.R_ESP);
421	printk("EBP=%08x  ", M.x86.R_EBP);
422	printk("ESI=%08x  ", M.x86.R_ESI);
423	printk("EDI=%08x\n", M.x86.R_EDI);
424	printk("\tDS=%04x  ", M.x86.R_DS);
425	printk("ES=%04x  ", M.x86.R_ES);
426	printk("SS=%04x  ", M.x86.R_SS);
427	printk("CS=%04x  ", M.x86.R_CS);
428	printk("EIP=%08x\n\t", M.x86.R_EIP);
429	if (ACCESS_FLAG(F_OF))
430		printk("OV ");	/* CHECKED... */
431	else
432		printk("NV ");
433	if (ACCESS_FLAG(F_DF))
434		printk("DN ");
435	else
436		printk("UP ");
437	if (ACCESS_FLAG(F_IF))
438		printk("EI ");
439	else
440		printk("DI ");
441	if (ACCESS_FLAG(F_SF))
442		printk("NG ");
443	else
444		printk("PL ");
445	if (ACCESS_FLAG(F_ZF))
446		printk("ZR ");
447	else
448		printk("NZ ");
449	if (ACCESS_FLAG(F_AF))
450		printk("AC ");
451	else
452		printk("NA ");
453	if (ACCESS_FLAG(F_PF))
454		printk("PE ");
455	else
456		printk("PO ");
457	if (ACCESS_FLAG(F_CF))
458		printk("CY ");
459	else
460		printk("NC ");
461	printk("\n");
462}
463