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root/cebix/BasiliskII/src/Unix/sigsegv.cpp
Revision: 1.20
Committed: 2002-07-17T06:51:05Z (22 years, 3 months ago) by gbeauche
Branch: MAIN
Changes since 1.19: +6 -0 lines
Log Message:
- New arch support for IP retrieval on SIGSEGV.

File Contents

# User Rev Content
1 gbeauche 1.1 /*
2     * sigsegv.cpp - SIGSEGV signals support
3     *
4     * Derived from Bruno Haible's work on his SIGSEGV library for clisp
5     * <http://clisp.sourceforge.net/>
6     *
7 cebix 1.7 * Basilisk II (C) 1997-2002 Christian Bauer
8 gbeauche 1.1 *
9     * This program is free software; you can redistribute it and/or modify
10     * it under the terms of the GNU General Public License as published by
11     * the Free Software Foundation; either version 2 of the License, or
12     * (at your option) any later version.
13     *
14     * This program is distributed in the hope that it will be useful,
15     * but WITHOUT ANY WARRANTY; without even the implied warranty of
16     * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17     * GNU General Public License for more details.
18     *
19     * You should have received a copy of the GNU General Public License
20     * along with this program; if not, write to the Free Software
21     * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
22     */
23    
24     #ifdef HAVE_UNISTD_H
25     #include <unistd.h>
26     #endif
27    
28     #ifdef HAVE_CONFIG_H
29     #include "config.h"
30     #endif
31    
32     #include <signal.h>
33     #include "sigsegv.h"
34    
35     // Return value type of a signal handler (standard type if not defined)
36     #ifndef RETSIGTYPE
37     #define RETSIGTYPE void
38     #endif
39    
40     // Type of the system signal handler
41     typedef RETSIGTYPE (*signal_handler)(int);
42    
43 gbeauche 1.10 // Is the fault to be ignored?
44     static bool sigsegv_ignore_fault = false;
45    
46 gbeauche 1.1 // User's SIGSEGV handler
47 gbeauche 1.12 static sigsegv_fault_handler_t sigsegv_fault_handler = 0;
48 gbeauche 1.1
49 gbeauche 1.10 // Function called to dump state if we can't handle the fault
50 gbeauche 1.12 static sigsegv_state_dumper_t sigsegv_state_dumper = 0;
51 gbeauche 1.10
52 gbeauche 1.1 // Actual SIGSEGV handler installer
53     static bool sigsegv_do_install_handler(int sig);
54    
55    
56     /*
57 gbeauche 1.14 * Instruction decoding aids
58     */
59    
60     // Transfer type
61     enum transfer_type_t {
62     TYPE_UNKNOWN,
63     TYPE_LOAD,
64     TYPE_STORE
65     };
66    
67     // Transfer size
68     enum transfer_size_t {
69     SIZE_UNKNOWN,
70     SIZE_BYTE,
71     SIZE_WORD,
72     SIZE_LONG
73     };
74    
75     #if (defined(powerpc) || defined(__powerpc__) || defined(__ppc__))
76     // Addressing mode
77     enum addressing_mode_t {
78     MODE_UNKNOWN,
79     MODE_NORM,
80     MODE_U,
81     MODE_X,
82     MODE_UX
83     };
84    
85     // Decoded instruction
86     struct instruction_t {
87     transfer_type_t transfer_type;
88     transfer_size_t transfer_size;
89     addressing_mode_t addr_mode;
90     unsigned int addr;
91     char ra, rd;
92     };
93    
94     static void powerpc_decode_instruction(instruction_t *instruction, unsigned int nip, unsigned int * gpr)
95     {
96     // Get opcode and divide into fields
97     unsigned int opcode = *((unsigned int *)nip);
98     unsigned int primop = opcode >> 26;
99     unsigned int exop = (opcode >> 1) & 0x3ff;
100     unsigned int ra = (opcode >> 16) & 0x1f;
101     unsigned int rb = (opcode >> 11) & 0x1f;
102     unsigned int rd = (opcode >> 21) & 0x1f;
103     signed int imm = (signed short)(opcode & 0xffff);
104    
105     // Analyze opcode
106     transfer_type_t transfer_type = TYPE_UNKNOWN;
107     transfer_size_t transfer_size = SIZE_UNKNOWN;
108     addressing_mode_t addr_mode = MODE_UNKNOWN;
109     switch (primop) {
110     case 31:
111     switch (exop) {
112     case 23: // lwzx
113     transfer_type = TYPE_LOAD; transfer_size = SIZE_LONG; addr_mode = MODE_X; break;
114     case 55: // lwzux
115     transfer_type = TYPE_LOAD; transfer_size = SIZE_LONG; addr_mode = MODE_UX; break;
116     case 87: // lbzx
117     transfer_type = TYPE_LOAD; transfer_size = SIZE_BYTE; addr_mode = MODE_X; break;
118     case 119: // lbzux
119     transfer_type = TYPE_LOAD; transfer_size = SIZE_BYTE; addr_mode = MODE_UX; break;
120     case 151: // stwx
121     transfer_type = TYPE_STORE; transfer_size = SIZE_LONG; addr_mode = MODE_X; break;
122     case 183: // stwux
123     transfer_type = TYPE_STORE; transfer_size = SIZE_LONG; addr_mode = MODE_UX; break;
124     case 215: // stbx
125     transfer_type = TYPE_STORE; transfer_size = SIZE_BYTE; addr_mode = MODE_X; break;
126     case 247: // stbux
127     transfer_type = TYPE_STORE; transfer_size = SIZE_BYTE; addr_mode = MODE_UX; break;
128     case 279: // lhzx
129     transfer_type = TYPE_LOAD; transfer_size = SIZE_WORD; addr_mode = MODE_X; break;
130     case 311: // lhzux
131     transfer_type = TYPE_LOAD; transfer_size = SIZE_WORD; addr_mode = MODE_UX; break;
132     case 343: // lhax
133     transfer_type = TYPE_LOAD; transfer_size = SIZE_WORD; addr_mode = MODE_X; break;
134     case 375: // lhaux
135     transfer_type = TYPE_LOAD; transfer_size = SIZE_WORD; addr_mode = MODE_UX; break;
136     case 407: // sthx
137     transfer_type = TYPE_STORE; transfer_size = SIZE_WORD; addr_mode = MODE_X; break;
138     case 439: // sthux
139     transfer_type = TYPE_STORE; transfer_size = SIZE_WORD; addr_mode = MODE_UX; break;
140     }
141     break;
142    
143     case 32: // lwz
144     transfer_type = TYPE_LOAD; transfer_size = SIZE_LONG; addr_mode = MODE_NORM; break;
145     case 33: // lwzu
146     transfer_type = TYPE_LOAD; transfer_size = SIZE_LONG; addr_mode = MODE_U; break;
147     case 34: // lbz
148     transfer_type = TYPE_LOAD; transfer_size = SIZE_BYTE; addr_mode = MODE_NORM; break;
149     case 35: // lbzu
150     transfer_type = TYPE_LOAD; transfer_size = SIZE_BYTE; addr_mode = MODE_U; break;
151     case 36: // stw
152     transfer_type = TYPE_STORE; transfer_size = SIZE_LONG; addr_mode = MODE_NORM; break;
153     case 37: // stwu
154     transfer_type = TYPE_STORE; transfer_size = SIZE_LONG; addr_mode = MODE_U; break;
155     case 38: // stb
156     transfer_type = TYPE_STORE; transfer_size = SIZE_BYTE; addr_mode = MODE_NORM; break;
157     case 39: // stbu
158     transfer_type = TYPE_STORE; transfer_size = SIZE_BYTE; addr_mode = MODE_U; break;
159     case 40: // lhz
160     transfer_type = TYPE_LOAD; transfer_size = SIZE_WORD; addr_mode = MODE_NORM; break;
161     case 41: // lhzu
162     transfer_type = TYPE_LOAD; transfer_size = SIZE_WORD; addr_mode = MODE_U; break;
163     case 42: // lha
164     transfer_type = TYPE_LOAD; transfer_size = SIZE_WORD; addr_mode = MODE_NORM; break;
165     case 43: // lhau
166     transfer_type = TYPE_LOAD; transfer_size = SIZE_WORD; addr_mode = MODE_U; break;
167     case 44: // sth
168     transfer_type = TYPE_STORE; transfer_size = SIZE_WORD; addr_mode = MODE_NORM; break;
169     case 45: // sthu
170     transfer_type = TYPE_STORE; transfer_size = SIZE_WORD; addr_mode = MODE_U; break;
171     }
172    
173     // Calculate effective address
174     unsigned int addr = 0;
175     switch (addr_mode) {
176     case MODE_X:
177     case MODE_UX:
178     if (ra == 0)
179     addr = gpr[rb];
180     else
181     addr = gpr[ra] + gpr[rb];
182     break;
183     case MODE_NORM:
184     case MODE_U:
185     if (ra == 0)
186     addr = (signed int)(signed short)imm;
187     else
188     addr = gpr[ra] + (signed int)(signed short)imm;
189     break;
190     default:
191     break;
192     }
193    
194     // Commit decoded instruction
195     instruction->addr = addr;
196     instruction->addr_mode = addr_mode;
197     instruction->transfer_type = transfer_type;
198     instruction->transfer_size = transfer_size;
199     instruction->ra = ra;
200     instruction->rd = rd;
201     }
202     #endif
203    
204    
205     /*
206 gbeauche 1.1 * OS-dependant SIGSEGV signals support section
207     */
208    
209     #if HAVE_SIGINFO_T
210     // Generic extended signal handler
211 cebix 1.8 #if defined(__NetBSD__) || defined(__FreeBSD__)
212     #define SIGSEGV_ALL_SIGNALS FAULT_HANDLER(SIGBUS)
213     #else
214 gbeauche 1.1 #define SIGSEGV_ALL_SIGNALS FAULT_HANDLER(SIGSEGV)
215 cebix 1.8 #endif
216 gbeauche 1.5 #define SIGSEGV_FAULT_HANDLER_ARGLIST int sig, siginfo_t *sip, void *scp
217 gbeauche 1.1 #define SIGSEGV_FAULT_ADDRESS sip->si_addr
218 gbeauche 1.19 #if defined(__NetBSD__) || defined(__FreeBSD__)
219 gbeauche 1.17 #if (defined(i386) || defined(__i386__))
220     #define SIGSEGV_FAULT_INSTRUCTION (((struct sigcontext *)scp)->sc_eip)
221 gbeauche 1.18 #define SIGSEGV_REGISTER_FILE ((unsigned int *)&(((struct sigcontext *)scp)->sc_edi)) /* EDI is the first GPR (even below EIP) in sigcontext */
222     /* (gb) Disable because this would hang configure script for some reason
223     * though standalone testing gets it right. Any idea why?
224 gbeauche 1.17 #define SIGSEGV_SKIP_INSTRUCTION ix86_skip_instruction
225 gbeauche 1.18 */
226 gbeauche 1.19 #endif
227 gbeauche 1.17 #endif
228 gbeauche 1.5 #if defined(__linux__)
229 gbeauche 1.6 #if (defined(i386) || defined(__i386__))
230     #include <sys/ucontext.h>
231 gbeauche 1.14 #define SIGSEGV_CONTEXT_REGS (((ucontext_t *)scp)->uc_mcontext.gregs)
232     #define SIGSEGV_FAULT_INSTRUCTION SIGSEGV_CONTEXT_REGS[14] /* should use REG_EIP instead */
233     #define SIGSEGV_REGISTER_FILE (unsigned int *)SIGSEGV_CONTEXT_REGS
234 gbeauche 1.10 #define SIGSEGV_SKIP_INSTRUCTION ix86_skip_instruction
235 gbeauche 1.6 #endif
236 gbeauche 1.20 #if (defined(x86_64) || defined(__x86_64__))
237     #include <sys/ucontext.h>
238     #define SIGSEGV_CONTEXT_REGS (((ucontext_t *)scp)->uc_mcontext.gregs)
239     #define SIGSEGV_FAULT_INSTRUCTION SIGSEGV_CONTEXT_REGS[16] /* should use REG_RIP instead */
240     #define SIGSEGV_REGISTER_FILE (unsigned long *)SIGSEGV_CONTEXT_REGS
241     #endif
242 gbeauche 1.5 #if (defined(ia64) || defined(__ia64__))
243     #define SIGSEGV_FAULT_INSTRUCTION (((struct sigcontext *)scp)->sc_ip & ~0x3ULL) /* slot number is in bits 0 and 1 */
244     #endif
245 gbeauche 1.9 #if (defined(powerpc) || defined(__powerpc__))
246     #include <sys/ucontext.h>
247 gbeauche 1.14 #define SIGSEGV_CONTEXT_REGS (((ucontext_t *)scp)->uc_mcontext.regs)
248     #define SIGSEGV_FAULT_INSTRUCTION (SIGSEGV_CONTEXT_REGS->nip)
249     #define SIGSEGV_REGISTER_FILE (unsigned int *)&SIGSEGV_CONTEXT_REGS->nip, (unsigned int *)(SIGSEGV_CONTEXT_REGS->gpr)
250 gbeauche 1.13 #define SIGSEGV_SKIP_INSTRUCTION powerpc_skip_instruction
251 gbeauche 1.9 #endif
252 gbeauche 1.5 #endif
253 gbeauche 1.1 #endif
254    
255     #if HAVE_SIGCONTEXT_SUBTERFUGE
256     // Linux kernels prior to 2.4 ?
257     #if defined(__linux__)
258     #define SIGSEGV_ALL_SIGNALS FAULT_HANDLER(SIGSEGV)
259     #if (defined(i386) || defined(__i386__))
260     #include <asm/sigcontext.h>
261     #define SIGSEGV_FAULT_HANDLER_ARGLIST int sig, struct sigcontext scs
262     #define SIGSEGV_FAULT_ADDRESS scs.cr2
263     #define SIGSEGV_FAULT_INSTRUCTION scs.eip
264 gbeauche 1.16 #define SIGSEGV_REGISTER_FILE (unsigned int *)(&scs)
265 gbeauche 1.10 #define SIGSEGV_SKIP_INSTRUCTION ix86_skip_instruction
266 gbeauche 1.1 #endif
267     #if (defined(sparc) || defined(__sparc__))
268     #include <asm/sigcontext.h>
269 gbeauche 1.5 #define SIGSEGV_FAULT_HANDLER_ARGLIST int sig, int code, struct sigcontext *scp, char *addr
270 gbeauche 1.1 #define SIGSEGV_FAULT_ADDRESS addr
271     #endif
272     #if (defined(powerpc) || defined(__powerpc__))
273     #include <asm/sigcontext.h>
274 gbeauche 1.4 #define SIGSEGV_FAULT_HANDLER_ARGLIST int sig, struct sigcontext *scp
275 gbeauche 1.1 #define SIGSEGV_FAULT_ADDRESS scp->regs->dar
276     #define SIGSEGV_FAULT_INSTRUCTION scp->regs->nip
277 gbeauche 1.14 #define SIGSEGV_REGISTER_FILE (unsigned int *)&scp->regs->nip, (unsigned int *)(scp->regs->gpr)
278 gbeauche 1.13 #define SIGSEGV_SKIP_INSTRUCTION powerpc_skip_instruction
279 gbeauche 1.1 #endif
280 gbeauche 1.4 #if (defined(alpha) || defined(__alpha__))
281     #include <asm/sigcontext.h>
282     #define SIGSEGV_FAULT_HANDLER_ARGLIST int sig, int code, struct sigcontext *scp
283     #define SIGSEGV_FAULT_ADDRESS get_fault_address(scp)
284     #define SIGSEGV_FAULT_INSTRUCTION scp->sc_pc
285    
286     // From Boehm's GC 6.0alpha8
287     static sigsegv_address_t get_fault_address(struct sigcontext *scp)
288     {
289     unsigned int instruction = *((unsigned int *)(scp->sc_pc));
290     unsigned long fault_address = scp->sc_regs[(instruction >> 16) & 0x1f];
291     fault_address += (signed long)(signed short)(instruction & 0xffff);
292     return (sigsegv_address_t)fault_address;
293     }
294     #endif
295 gbeauche 1.1 #endif
296    
297     // Irix 5 or 6 on MIPS
298     #if (defined(sgi) || defined(__sgi)) && (defined(SYSTYPE_SVR4) || defined(__SYSTYPE_SVR4))
299 gbeauche 1.11 #include <ucontext.h>
300 gbeauche 1.1 #define SIGSEGV_FAULT_HANDLER_ARGLIST int sig, int code, struct sigcontext *scp
301     #define SIGSEGV_FAULT_ADDRESS scp->sc_badvaddr
302     #define SIGSEGV_ALL_SIGNALS FAULT_HANDLER(SIGSEGV)
303     #endif
304    
305 gbeauche 1.11 // HP-UX
306     #if (defined(hpux) || defined(__hpux__))
307     #define SIGSEGV_FAULT_HANDLER_ARGLIST int sig, int code, struct sigcontext *scp
308     #define SIGSEGV_FAULT_ADDRESS scp->sc_sl.sl_ss.ss_narrow.ss_cr21
309     #define SIGSEGV_ALL_SIGNALS FAULT_HANDLER(SIGSEGV) FAULT_HANDLER(SIGBUS)
310     #endif
311    
312 gbeauche 1.1 // OSF/1 on Alpha
313     #if defined(__osf__)
314 gbeauche 1.11 #include <ucontext.h>
315 gbeauche 1.1 #define SIGSEGV_FAULT_HANDLER_ARGLIST int sig, int code, struct sigcontext *scp
316     #define SIGSEGV_FAULT_ADDRESS scp->sc_traparg_a0
317     #define SIGSEGV_ALL_SIGNALS FAULT_HANDLER(SIGSEGV)
318     #endif
319    
320     // AIX
321     #if defined(_AIX)
322     #define SIGSEGV_FAULT_HANDLER_ARGLIST int sig, int code, struct sigcontext *scp
323     #define SIGSEGV_FAULT_ADDRESS scp->sc_jmpbuf.jmp_context.o_vaddr
324     #define SIGSEGV_ALL_SIGNALS FAULT_HANDLER(SIGSEGV)
325     #endif
326    
327     // NetBSD or FreeBSD
328     #if defined(__NetBSD__) || defined(__FreeBSD__)
329     #if (defined(m68k) || defined(__m68k__))
330     #include <m68k/frame.h>
331     #define SIGSEGV_FAULT_HANDLER_ARGLIST int sig, int code, struct sigcontext *scp
332 gbeauche 1.14 #define SIGSEGV_FAULT_ADDRESS get_fault_address(scp)
333 gbeauche 1.1 #define SIGSEGV_ALL_SIGNALS FAULT_HANDLER(SIGSEGV)
334 gbeauche 1.14
335     // Use decoding scheme from BasiliskII/m68k native
336     static sigsegv_address_t get_fault_address(struct sigcontext *scp)
337     {
338     struct sigstate {
339     int ss_flags;
340     struct frame ss_frame;
341     };
342     struct sigstate *state = (struct sigstate *)scp->sc_ap;
343     char *fault_addr;
344     switch (state->ss_frame.f_format) {
345     case 7: /* 68040 access error */
346     /* "code" is sometimes unreliable (i.e. contains NULL or a bogus address), reason unknown */
347     fault_addr = state->ss_frame.f_fmt7.f_fa;
348     break;
349     default:
350     fault_addr = (char *)code;
351     break;
352     }
353     return (sigsegv_address_t)fault_addr;
354     }
355 gbeauche 1.1 #else
356     #define SIGSEGV_FAULT_HANDLER_ARGLIST int sig, int code, void *scp, char *addr
357     #define SIGSEGV_FAULT_ADDRESS addr
358     #define SIGSEGV_ALL_SIGNALS FAULT_HANDLER(SIGBUS)
359     #endif
360     #endif
361 gbeauche 1.4
362     // MacOS X
363     #if defined(__APPLE__) && defined(__MACH__)
364     #if (defined(ppc) || defined(__ppc__))
365     #define SIGSEGV_FAULT_HANDLER_ARGLIST int sig, int code, struct sigcontext *scp
366     #define SIGSEGV_FAULT_ADDRESS get_fault_address(scp)
367     #define SIGSEGV_FAULT_INSTRUCTION scp->sc_ir
368     #define SIGSEGV_ALL_SIGNALS FAULT_HANDLER(SIGBUS)
369 gbeauche 1.14 #define SIGSEGV_REGISTER_FILE (unsigned int *)&scp->sc_ir, &((unsigned int *) scp->sc_regs)[2]
370     #define SIGSEGV_SKIP_INSTRUCTION powerpc_skip_instruction
371 gbeauche 1.4
372 gbeauche 1.14 // Use decoding scheme from SheepShaver
373 gbeauche 1.4 static sigsegv_address_t get_fault_address(struct sigcontext *scp)
374     {
375 gbeauche 1.14 unsigned int nip = (unsigned int) scp->sc_ir;
376     unsigned int * gpr = &((unsigned int *) scp->sc_regs)[2];
377     instruction_t instr;
378    
379     powerpc_decode_instruction(&instr, nip, gpr);
380     return (sigsegv_address_t)instr.addr;
381 gbeauche 1.4 }
382     #endif
383     #endif
384 gbeauche 1.1 #endif
385    
386 gbeauche 1.14
387     /*
388     * Instruction skipping
389     */
390    
391 gbeauche 1.10 #ifdef HAVE_SIGSEGV_SKIP_INSTRUCTION
392     // Decode and skip X86 instruction
393     #if (defined(i386) || defined(__i386__))
394     #if defined(__linux__)
395     enum {
396     X86_REG_EIP = 14,
397     X86_REG_EAX = 11,
398     X86_REG_ECX = 10,
399     X86_REG_EDX = 9,
400     X86_REG_EBX = 8,
401     X86_REG_ESP = 7,
402     X86_REG_EBP = 6,
403     X86_REG_ESI = 5,
404     X86_REG_EDI = 4
405     };
406     #endif
407 gbeauche 1.17 #if defined(__NetBSD__) || defined(__FreeBSD__)
408     enum {
409     X86_REG_EIP = 10,
410     X86_REG_EAX = 7,
411     X86_REG_ECX = 6,
412     X86_REG_EDX = 5,
413     X86_REG_EBX = 4,
414     X86_REG_ESP = 13,
415     X86_REG_EBP = 2,
416     X86_REG_ESI = 1,
417     X86_REG_EDI = 0
418     };
419     #endif
420 gbeauche 1.10 // FIXME: this is partly redundant with the instruction decoding phase
421     // to discover transfer type and register number
422     static inline int ix86_step_over_modrm(unsigned char * p)
423     {
424     int mod = (p[0] >> 6) & 3;
425     int rm = p[0] & 7;
426     int offset = 0;
427    
428     // ModR/M Byte
429     switch (mod) {
430     case 0: // [reg]
431     if (rm == 5) return 4; // disp32
432     break;
433     case 1: // disp8[reg]
434     offset = 1;
435     break;
436     case 2: // disp32[reg]
437     offset = 4;
438     break;
439     case 3: // register
440     return 0;
441     }
442    
443     // SIB Byte
444     if (rm == 4) {
445     if (mod == 0 && (p[1] & 7) == 5)
446     offset = 5; // disp32[index]
447     else
448     offset++;
449     }
450    
451     return offset;
452     }
453    
454 gbeauche 1.14 static bool ix86_skip_instruction(unsigned int * regs)
455 gbeauche 1.10 {
456 gbeauche 1.14 unsigned char * eip = (unsigned char *)regs[X86_REG_EIP];
457 gbeauche 1.10
458     if (eip == 0)
459     return false;
460    
461 gbeauche 1.14 transfer_type_t transfer_type = TYPE_UNKNOWN;
462     transfer_size_t transfer_size = SIZE_LONG;
463 gbeauche 1.10
464     int reg = -1;
465     int len = 0;
466    
467     // Operand size prefix
468     if (*eip == 0x66) {
469     eip++;
470     len++;
471     transfer_size = SIZE_WORD;
472     }
473    
474     // Decode instruction
475     switch (eip[0]) {
476 gbeauche 1.17 case 0x0f:
477 gbeauche 1.18 switch (eip[1]) {
478     case 0xb6: // MOVZX r32, r/m8
479     case 0xb7: // MOVZX r32, r/m16
480 gbeauche 1.17 switch (eip[2] & 0xc0) {
481     case 0x80:
482     reg = (eip[2] >> 3) & 7;
483     transfer_type = TYPE_LOAD;
484     break;
485     case 0x40:
486     reg = (eip[2] >> 3) & 7;
487     transfer_type = TYPE_LOAD;
488     break;
489     case 0x00:
490     reg = (eip[2] >> 3) & 7;
491     transfer_type = TYPE_LOAD;
492     break;
493     }
494     len += 3 + ix86_step_over_modrm(eip + 2);
495 gbeauche 1.18 break;
496 gbeauche 1.17 }
497     break;
498 gbeauche 1.10 case 0x8a: // MOV r8, r/m8
499     transfer_size = SIZE_BYTE;
500     case 0x8b: // MOV r32, r/m32 (or 16-bit operation)
501     switch (eip[1] & 0xc0) {
502     case 0x80:
503     reg = (eip[1] >> 3) & 7;
504     transfer_type = TYPE_LOAD;
505     break;
506     case 0x40:
507     reg = (eip[1] >> 3) & 7;
508     transfer_type = TYPE_LOAD;
509     break;
510     case 0x00:
511     reg = (eip[1] >> 3) & 7;
512     transfer_type = TYPE_LOAD;
513     break;
514     }
515     len += 2 + ix86_step_over_modrm(eip + 1);
516     break;
517     case 0x88: // MOV r/m8, r8
518     transfer_size = SIZE_BYTE;
519     case 0x89: // MOV r/m32, r32 (or 16-bit operation)
520     switch (eip[1] & 0xc0) {
521     case 0x80:
522     reg = (eip[1] >> 3) & 7;
523     transfer_type = TYPE_STORE;
524     break;
525     case 0x40:
526     reg = (eip[1] >> 3) & 7;
527     transfer_type = TYPE_STORE;
528     break;
529     case 0x00:
530     reg = (eip[1] >> 3) & 7;
531     transfer_type = TYPE_STORE;
532     break;
533     }
534     len += 2 + ix86_step_over_modrm(eip + 1);
535     break;
536     }
537    
538     if (transfer_type == TYPE_UNKNOWN) {
539     // Unknown machine code, let it crash. Then patch the decoder
540     return false;
541     }
542    
543     if (transfer_type == TYPE_LOAD && reg != -1) {
544     static const int x86_reg_map[8] = {
545     X86_REG_EAX, X86_REG_ECX, X86_REG_EDX, X86_REG_EBX,
546     X86_REG_ESP, X86_REG_EBP, X86_REG_ESI, X86_REG_EDI
547     };
548    
549     if (reg < 0 || reg >= 8)
550     return false;
551    
552     int rloc = x86_reg_map[reg];
553     switch (transfer_size) {
554     case SIZE_BYTE:
555     regs[rloc] = (regs[rloc] & ~0xff);
556     break;
557     case SIZE_WORD:
558     regs[rloc] = (regs[rloc] & ~0xffff);
559     break;
560     case SIZE_LONG:
561     regs[rloc] = 0;
562     break;
563     }
564     }
565    
566     #if DEBUG
567 gbeauche 1.15 printf("%08x: %s %s access", regs[X86_REG_EIP],
568 gbeauche 1.10 transfer_size == SIZE_BYTE ? "byte" : transfer_size == SIZE_WORD ? "word" : "long",
569     transfer_type == TYPE_LOAD ? "read" : "write");
570    
571     if (reg != -1) {
572     static const char * x86_reg_str_map[8] = {
573     "eax", "ecx", "edx", "ebx",
574     "esp", "ebp", "esi", "edi"
575     };
576     printf(" %s register %%%s", transfer_type == TYPE_LOAD ? "to" : "from", x86_reg_str_map[reg]);
577     }
578     printf(", %d bytes instruction\n", len);
579     #endif
580    
581     regs[X86_REG_EIP] += len;
582 gbeauche 1.13 return true;
583     }
584     #endif
585 gbeauche 1.14
586 gbeauche 1.13 // Decode and skip PPC instruction
587 gbeauche 1.14 #if (defined(powerpc) || defined(__powerpc__) || defined(__ppc__))
588     static bool powerpc_skip_instruction(unsigned int * nip_p, unsigned int * regs)
589 gbeauche 1.13 {
590 gbeauche 1.14 instruction_t instr;
591     powerpc_decode_instruction(&instr, *nip_p, regs);
592 gbeauche 1.13
593 gbeauche 1.14 if (instr.transfer_type == TYPE_UNKNOWN) {
594 gbeauche 1.13 // Unknown machine code, let it crash. Then patch the decoder
595     return false;
596     }
597    
598     #if DEBUG
599 gbeauche 1.14 printf("%08x: %s %s access", *nip_p,
600     instr.transfer_size == SIZE_BYTE ? "byte" : instr.transfer_size == SIZE_WORD ? "word" : "long",
601     instr.transfer_type == TYPE_LOAD ? "read" : "write");
602    
603     if (instr.addr_mode == MODE_U || instr.addr_mode == MODE_UX)
604     printf(" r%d (ra = %08x)\n", instr.ra, instr.addr);
605     if (instr.transfer_type == TYPE_LOAD)
606     printf(" r%d (rd = 0)\n", instr.rd);
607     #endif
608    
609     if (instr.addr_mode == MODE_U || instr.addr_mode == MODE_UX)
610     regs[instr.ra] = instr.addr;
611     if (instr.transfer_type == TYPE_LOAD)
612     regs[instr.rd] = 0;
613 gbeauche 1.13
614 gbeauche 1.14 *nip_p += 4;
615 gbeauche 1.10 return true;
616     }
617     #endif
618     #endif
619    
620 gbeauche 1.1 // Fallbacks
621     #ifndef SIGSEGV_FAULT_INSTRUCTION
622     #define SIGSEGV_FAULT_INSTRUCTION SIGSEGV_INVALID_PC
623     #endif
624    
625 gbeauche 1.2 // SIGSEGV recovery supported ?
626     #if defined(SIGSEGV_ALL_SIGNALS) && defined(SIGSEGV_FAULT_HANDLER_ARGLIST) && defined(SIGSEGV_FAULT_ADDRESS)
627     #define HAVE_SIGSEGV_RECOVERY
628     #endif
629    
630 gbeauche 1.1
631     /*
632     * SIGSEGV global handler
633     */
634    
635 gbeauche 1.2 #ifdef HAVE_SIGSEGV_RECOVERY
636 gbeauche 1.1 static void sigsegv_handler(SIGSEGV_FAULT_HANDLER_ARGLIST)
637     {
638 gbeauche 1.10 sigsegv_address_t fault_address = (sigsegv_address_t)SIGSEGV_FAULT_ADDRESS;
639     sigsegv_address_t fault_instruction = (sigsegv_address_t)SIGSEGV_FAULT_INSTRUCTION;
640     bool fault_recovered = false;
641    
642 gbeauche 1.1 // Call user's handler and reinstall the global handler, if required
643 gbeauche 1.12 if (sigsegv_fault_handler(fault_address, fault_instruction)) {
644 gbeauche 1.1 #if (defined(HAVE_SIGACTION) ? defined(SIGACTION_NEED_REINSTALL) : defined(SIGNAL_NEED_REINSTALL))
645     sigsegv_do_install_handler(sig);
646     #endif
647 gbeauche 1.10 fault_recovered = true;
648 gbeauche 1.1 }
649 gbeauche 1.10 #if HAVE_SIGSEGV_SKIP_INSTRUCTION
650     else if (sigsegv_ignore_fault) {
651     // Call the instruction skipper with the register file available
652 gbeauche 1.14 if (SIGSEGV_SKIP_INSTRUCTION(SIGSEGV_REGISTER_FILE))
653 gbeauche 1.10 fault_recovered = true;
654     }
655     #endif
656    
657     if (!fault_recovered) {
658 gbeauche 1.1 // FAIL: reinstall default handler for "safe" crash
659     #define FAULT_HANDLER(sig) signal(sig, SIG_DFL);
660     SIGSEGV_ALL_SIGNALS
661     #undef FAULT_HANDLER
662 gbeauche 1.10
663     // We can't do anything with the fault_address, dump state?
664 gbeauche 1.12 if (sigsegv_state_dumper != 0)
665     sigsegv_state_dumper(fault_address, fault_instruction);
666 gbeauche 1.1 }
667     }
668 gbeauche 1.2 #endif
669 gbeauche 1.1
670    
671     /*
672     * SIGSEGV handler initialization
673     */
674    
675     #if defined(HAVE_SIGINFO_T)
676     static bool sigsegv_do_install_handler(int sig)
677     {
678     // Setup SIGSEGV handler to process writes to frame buffer
679     #ifdef HAVE_SIGACTION
680     struct sigaction vosf_sa;
681     sigemptyset(&vosf_sa.sa_mask);
682     vosf_sa.sa_sigaction = sigsegv_handler;
683     vosf_sa.sa_flags = SA_SIGINFO;
684     return (sigaction(sig, &vosf_sa, 0) == 0);
685     #else
686     return (signal(sig, (signal_handler)sigsegv_handler) != SIG_ERR);
687     #endif
688     }
689 gbeauche 1.2 #endif
690    
691     #if defined(HAVE_SIGCONTEXT_SUBTERFUGE)
692 gbeauche 1.1 static bool sigsegv_do_install_handler(int sig)
693     {
694     // Setup SIGSEGV handler to process writes to frame buffer
695     #ifdef HAVE_SIGACTION
696     struct sigaction vosf_sa;
697     sigemptyset(&vosf_sa.sa_mask);
698     vosf_sa.sa_handler = (signal_handler)sigsegv_handler;
699     #if !EMULATED_68K && defined(__NetBSD__)
700     sigaddset(&vosf_sa.sa_mask, SIGALRM);
701     vosf_sa.sa_flags = SA_ONSTACK;
702     #else
703     vosf_sa.sa_flags = 0;
704     #endif
705     return (sigaction(sig, &vosf_sa, 0) == 0);
706     #else
707     return (signal(sig, (signal_handler)sigsegv_handler) != SIG_ERR);
708     #endif
709     }
710     #endif
711    
712 gbeauche 1.12 bool sigsegv_install_handler(sigsegv_fault_handler_t handler)
713 gbeauche 1.1 {
714 gbeauche 1.2 #ifdef HAVE_SIGSEGV_RECOVERY
715 gbeauche 1.12 sigsegv_fault_handler = handler;
716 gbeauche 1.1 bool success = true;
717     #define FAULT_HANDLER(sig) success = success && sigsegv_do_install_handler(sig);
718     SIGSEGV_ALL_SIGNALS
719     #undef FAULT_HANDLER
720     return success;
721     #else
722     // FAIL: no siginfo_t nor sigcontext subterfuge is available
723     return false;
724     #endif
725     }
726    
727    
728     /*
729     * SIGSEGV handler deinitialization
730     */
731    
732     void sigsegv_deinstall_handler(void)
733     {
734 gbeauche 1.2 #ifdef HAVE_SIGSEGV_RECOVERY
735 gbeauche 1.12 sigsegv_fault_handler = 0;
736 gbeauche 1.1 #define FAULT_HANDLER(sig) signal(sig, SIG_DFL);
737     SIGSEGV_ALL_SIGNALS
738     #undef FAULT_HANDLER
739 gbeauche 1.2 #endif
740 gbeauche 1.1 }
741    
742 gbeauche 1.10
743     /*
744     * SIGSEGV ignore state modifier
745     */
746    
747     void sigsegv_set_ignore_state(bool ignore_fault)
748     {
749     sigsegv_ignore_fault = ignore_fault;
750     }
751    
752    
753     /*
754     * Set callback function when we cannot handle the fault
755     */
756    
757 gbeauche 1.12 void sigsegv_set_dump_state(sigsegv_state_dumper_t handler)
758 gbeauche 1.10 {
759 gbeauche 1.12 sigsegv_state_dumper = handler;
760 gbeauche 1.10 }
761    
762    
763 gbeauche 1.1 /*
764     * Test program used for configure/test
765     */
766    
767 gbeauche 1.4 #ifdef CONFIGURE_TEST_SIGSEGV_RECOVERY
768 gbeauche 1.1 #include <stdio.h>
769     #include <stdlib.h>
770     #include <fcntl.h>
771     #include <sys/mman.h>
772 gbeauche 1.4 #include "vm_alloc.h"
773 gbeauche 1.1
774     static int page_size;
775 gbeauche 1.3 static volatile char * page = 0;
776     static volatile int handler_called = 0;
777 gbeauche 1.1
778     static bool sigsegv_test_handler(sigsegv_address_t fault_address, sigsegv_address_t instruction_address)
779     {
780     handler_called++;
781     if ((fault_address - 123) != page)
782     exit(1);
783 gbeauche 1.4 if (vm_protect((char *)((unsigned long)fault_address & -page_size), page_size, VM_PAGE_READ | VM_PAGE_WRITE) != 0)
784 gbeauche 1.1 exit(1);
785     return true;
786     }
787    
788 gbeauche 1.10 #ifdef HAVE_SIGSEGV_SKIP_INSTRUCTION
789     static bool sigsegv_insn_handler(sigsegv_address_t fault_address, sigsegv_address_t instruction_address)
790     {
791     return false;
792     }
793     #endif
794    
795 gbeauche 1.1 int main(void)
796     {
797 gbeauche 1.4 if (vm_init() < 0)
798 gbeauche 1.1 return 1;
799    
800     page_size = getpagesize();
801 gbeauche 1.4 if ((page = (char *)vm_acquire(page_size)) == VM_MAP_FAILED)
802     return 1;
803    
804     if (vm_protect((char *)page, page_size, VM_PAGE_READ) < 0)
805 gbeauche 1.1 return 1;
806    
807     if (!sigsegv_install_handler(sigsegv_test_handler))
808     return 1;
809    
810     page[123] = 45;
811     page[123] = 45;
812    
813     if (handler_called != 1)
814     return 1;
815 gbeauche 1.10
816     #ifdef HAVE_SIGSEGV_SKIP_INSTRUCTION
817     if (!sigsegv_install_handler(sigsegv_insn_handler))
818     return 1;
819    
820 gbeauche 1.17 if (vm_protect((char *)page, page_size, VM_PAGE_READ | VM_PAGE_WRITE) < 0)
821 gbeauche 1.10 return 1;
822    
823     for (int i = 0; i < page_size; i++)
824     page[i] = (i + 1) % page_size;
825    
826     if (vm_protect((char *)page, page_size, VM_PAGE_NOACCESS) < 0)
827     return 1;
828    
829     sigsegv_set_ignore_state(true);
830    
831     #define TEST_SKIP_INSTRUCTION(TYPE) do { \
832     const unsigned int TAG = 0x12345678; \
833     TYPE data = *((TYPE *)(page + sizeof(TYPE))); \
834     volatile unsigned int effect = data + TAG; \
835     if (effect != TAG) \
836     return 1; \
837     } while (0)
838    
839     TEST_SKIP_INSTRUCTION(unsigned char);
840     TEST_SKIP_INSTRUCTION(unsigned short);
841     TEST_SKIP_INSTRUCTION(unsigned int);
842     #endif
843 gbeauche 1.1
844 gbeauche 1.4 vm_exit();
845 gbeauche 1.1 return 0;
846     }
847     #endif