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root/cebix/BasiliskII/src/Unix/sigsegv.cpp
Revision: 1.13
Committed: 2002-05-19T21:58:42Z (22 years, 5 months ago) by gbeauche
Branch: MAIN
Changes since 1.12: +153 -1 lines
Log Message:
Implement "ignoresegv" feature on Linux/ppc:
- Unix/sigsegv.cpp (powerpc_skip_instruction): New from SheepShaver code.
- README (ignoresegv): Add Linux/ppc to list of supported platforms.

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     * OS-dependant SIGSEGV signals support section
58     */
59    
60     #if HAVE_SIGINFO_T
61     // Generic extended signal handler
62 cebix 1.8 #if defined(__NetBSD__) || defined(__FreeBSD__)
63     #define SIGSEGV_ALL_SIGNALS FAULT_HANDLER(SIGBUS)
64     #else
65 gbeauche 1.1 #define SIGSEGV_ALL_SIGNALS FAULT_HANDLER(SIGSEGV)
66 cebix 1.8 #endif
67 gbeauche 1.5 #define SIGSEGV_FAULT_HANDLER_ARGLIST int sig, siginfo_t *sip, void *scp
68 gbeauche 1.1 #define SIGSEGV_FAULT_ADDRESS sip->si_addr
69 gbeauche 1.5 #if defined(__linux__)
70 gbeauche 1.6 #if (defined(i386) || defined(__i386__))
71     #include <sys/ucontext.h>
72     #define SIGSEGV_FAULT_INSTRUCTION (((ucontext_t *)scp)->uc_mcontext.gregs[14]) /* should use REG_EIP instead */
73 gbeauche 1.10 #define SIGSEGV_REGISTER_FILE (unsigned long *)(((ucontext_t *)scp)->uc_mcontext.gregs)
74     #define SIGSEGV_SKIP_INSTRUCTION ix86_skip_instruction
75 gbeauche 1.6 #endif
76 gbeauche 1.5 #if (defined(ia64) || defined(__ia64__))
77     #define SIGSEGV_FAULT_INSTRUCTION (((struct sigcontext *)scp)->sc_ip & ~0x3ULL) /* slot number is in bits 0 and 1 */
78     #endif
79 gbeauche 1.9 #if (defined(powerpc) || defined(__powerpc__))
80     #include <sys/ucontext.h>
81     #define SIGSEGV_FAULT_INSTRUCTION (((ucontext_t *)scp)->uc_mcontext.regs->nip)
82 gbeauche 1.13 #define SIGSEGV_REGISTER_FILE (unsigned long *)(((ucontext_t *)scp)->uc_mcontext.regs)
83     #define SIGSEGV_SKIP_INSTRUCTION powerpc_skip_instruction
84 gbeauche 1.9 #endif
85 gbeauche 1.5 #endif
86 gbeauche 1.1 #endif
87    
88     #if HAVE_SIGCONTEXT_SUBTERFUGE
89     // Linux kernels prior to 2.4 ?
90     #if defined(__linux__)
91     #define SIGSEGV_ALL_SIGNALS FAULT_HANDLER(SIGSEGV)
92     #if (defined(i386) || defined(__i386__))
93     #include <asm/sigcontext.h>
94     #define SIGSEGV_FAULT_HANDLER_ARGLIST int sig, struct sigcontext scs
95     #define SIGSEGV_FAULT_ADDRESS scs.cr2
96     #define SIGSEGV_FAULT_INSTRUCTION scs.eip
97 gbeauche 1.10 #define SIGSEGV_REGISTER_FILE (unsigned long *)(&scs)
98     #define SIGSEGV_SKIP_INSTRUCTION ix86_skip_instruction
99 gbeauche 1.1 #endif
100     #if (defined(sparc) || defined(__sparc__))
101     #include <asm/sigcontext.h>
102 gbeauche 1.5 #define SIGSEGV_FAULT_HANDLER_ARGLIST int sig, int code, struct sigcontext *scp, char *addr
103 gbeauche 1.1 #define SIGSEGV_FAULT_ADDRESS addr
104     #endif
105     #if (defined(powerpc) || defined(__powerpc__))
106     #include <asm/sigcontext.h>
107 gbeauche 1.4 #define SIGSEGV_FAULT_HANDLER_ARGLIST int sig, struct sigcontext *scp
108 gbeauche 1.1 #define SIGSEGV_FAULT_ADDRESS scp->regs->dar
109     #define SIGSEGV_FAULT_INSTRUCTION scp->regs->nip
110 gbeauche 1.13 #define SIGSEGV_REGISTER_FILE (unsigned long *)(scp->regs)
111     #define SIGSEGV_SKIP_INSTRUCTION powerpc_skip_instruction
112 gbeauche 1.1 #endif
113 gbeauche 1.4 #if (defined(alpha) || defined(__alpha__))
114     #include <asm/sigcontext.h>
115     #define SIGSEGV_FAULT_HANDLER_ARGLIST int sig, int code, struct sigcontext *scp
116     #define SIGSEGV_FAULT_ADDRESS get_fault_address(scp)
117     #define SIGSEGV_FAULT_INSTRUCTION scp->sc_pc
118    
119     // From Boehm's GC 6.0alpha8
120     static sigsegv_address_t get_fault_address(struct sigcontext *scp)
121     {
122     unsigned int instruction = *((unsigned int *)(scp->sc_pc));
123     unsigned long fault_address = scp->sc_regs[(instruction >> 16) & 0x1f];
124     fault_address += (signed long)(signed short)(instruction & 0xffff);
125     return (sigsegv_address_t)fault_address;
126     }
127     #endif
128 gbeauche 1.1 #endif
129    
130     // Irix 5 or 6 on MIPS
131     #if (defined(sgi) || defined(__sgi)) && (defined(SYSTYPE_SVR4) || defined(__SYSTYPE_SVR4))
132 gbeauche 1.11 #include <ucontext.h>
133 gbeauche 1.1 #define SIGSEGV_FAULT_HANDLER_ARGLIST int sig, int code, struct sigcontext *scp
134     #define SIGSEGV_FAULT_ADDRESS scp->sc_badvaddr
135     #define SIGSEGV_ALL_SIGNALS FAULT_HANDLER(SIGSEGV)
136     #endif
137    
138 gbeauche 1.11 // HP-UX
139     #if (defined(hpux) || defined(__hpux__))
140     #define SIGSEGV_FAULT_HANDLER_ARGLIST int sig, int code, struct sigcontext *scp
141     #define SIGSEGV_FAULT_ADDRESS scp->sc_sl.sl_ss.ss_narrow.ss_cr21
142     #define SIGSEGV_ALL_SIGNALS FAULT_HANDLER(SIGSEGV) FAULT_HANDLER(SIGBUS)
143     #endif
144    
145 gbeauche 1.1 // OSF/1 on Alpha
146     #if defined(__osf__)
147 gbeauche 1.11 #include <ucontext.h>
148 gbeauche 1.1 #define SIGSEGV_FAULT_HANDLER_ARGLIST int sig, int code, struct sigcontext *scp
149     #define SIGSEGV_FAULT_ADDRESS scp->sc_traparg_a0
150     #define SIGSEGV_ALL_SIGNALS FAULT_HANDLER(SIGSEGV)
151     #endif
152    
153     // AIX
154     #if defined(_AIX)
155     #define SIGSEGV_FAULT_HANDLER_ARGLIST int sig, int code, struct sigcontext *scp
156     #define SIGSEGV_FAULT_ADDRESS scp->sc_jmpbuf.jmp_context.o_vaddr
157     #define SIGSEGV_ALL_SIGNALS FAULT_HANDLER(SIGSEGV)
158     #endif
159    
160     // NetBSD or FreeBSD
161     #if defined(__NetBSD__) || defined(__FreeBSD__)
162     #if (defined(m68k) || defined(__m68k__))
163     #include <m68k/frame.h>
164     #define SIGSEGV_FAULT_HANDLER_ARGLIST int sig, int code, struct sigcontext *scp
165     #define SIGSEGV_FAULT_ADDRESS ({ \
166     struct sigstate { \
167     int ss_flags; \
168     struct frame ss_frame; \
169     }; \
170     struct sigstate *state = (struct sigstate *)scp->sc_ap; \
171     char *fault_addr; \
172     switch (state->ss_frame.f_format) { \
173     case 7: /* 68040 access error */ \
174     /* "code" is sometimes unreliable (i.e. contains NULL or a bogus address), reason unknown */ \
175     fault_addr = state->ss_frame.f_fmt7.f_fa; \
176     break; \
177     default: \
178     fault_addr = (char *)code; \
179     break; \
180     } \
181     fault_addr; \
182     })
183     #define SIGSEGV_ALL_SIGNALS FAULT_HANDLER(SIGSEGV)
184     #else
185     #define SIGSEGV_FAULT_HANDLER_ARGLIST int sig, int code, void *scp, char *addr
186     #define SIGSEGV_FAULT_ADDRESS addr
187     #define SIGSEGV_ALL_SIGNALS FAULT_HANDLER(SIGBUS)
188     #endif
189     #endif
190 gbeauche 1.4
191     // MacOS X
192     #if defined(__APPLE__) && defined(__MACH__)
193     #if (defined(ppc) || defined(__ppc__))
194     #define SIGSEGV_FAULT_HANDLER_ARGLIST int sig, int code, struct sigcontext *scp
195     #define SIGSEGV_FAULT_ADDRESS get_fault_address(scp)
196     #define SIGSEGV_FAULT_INSTRUCTION scp->sc_ir
197     #define SIGSEGV_ALL_SIGNALS FAULT_HANDLER(SIGBUS)
198    
199     // From Boehm's GC 6.0alpha8
200     #define EXTRACT_OP1(iw) (((iw) & 0xFC000000) >> 26)
201     #define EXTRACT_OP2(iw) (((iw) & 0x000007FE) >> 1)
202     #define EXTRACT_REGA(iw) (((iw) & 0x001F0000) >> 16)
203     #define EXTRACT_REGB(iw) (((iw) & 0x03E00000) >> 21)
204     #define EXTRACT_REGC(iw) (((iw) & 0x0000F800) >> 11)
205     #define EXTRACT_DISP(iw) ((short *) &(iw))[1]
206    
207     static sigsegv_address_t get_fault_address(struct sigcontext *scp)
208     {
209     unsigned int instr = *((unsigned int *) scp->sc_ir);
210     unsigned int * regs = &((unsigned int *) scp->sc_regs)[2];
211     int disp = 0, tmp;
212     unsigned int baseA = 0, baseB = 0;
213     unsigned int addr, alignmask = 0xFFFFFFFF;
214    
215     switch(EXTRACT_OP1(instr)) {
216     case 38: /* stb */
217     case 39: /* stbu */
218     case 54: /* stfd */
219     case 55: /* stfdu */
220     case 52: /* stfs */
221     case 53: /* stfsu */
222     case 44: /* sth */
223     case 45: /* sthu */
224     case 47: /* stmw */
225     case 36: /* stw */
226     case 37: /* stwu */
227     tmp = EXTRACT_REGA(instr);
228     if(tmp > 0)
229     baseA = regs[tmp];
230     disp = EXTRACT_DISP(instr);
231     break;
232     case 31:
233     switch(EXTRACT_OP2(instr)) {
234     case 86: /* dcbf */
235     case 54: /* dcbst */
236     case 1014: /* dcbz */
237     case 247: /* stbux */
238     case 215: /* stbx */
239     case 759: /* stfdux */
240     case 727: /* stfdx */
241     case 983: /* stfiwx */
242     case 695: /* stfsux */
243     case 663: /* stfsx */
244     case 918: /* sthbrx */
245     case 439: /* sthux */
246     case 407: /* sthx */
247     case 661: /* stswx */
248     case 662: /* stwbrx */
249     case 150: /* stwcx. */
250     case 183: /* stwux */
251     case 151: /* stwx */
252     case 135: /* stvebx */
253     case 167: /* stvehx */
254     case 199: /* stvewx */
255     case 231: /* stvx */
256     case 487: /* stvxl */
257     tmp = EXTRACT_REGA(instr);
258     if(tmp > 0)
259     baseA = regs[tmp];
260     baseB = regs[EXTRACT_REGC(instr)];
261     /* determine Altivec alignment mask */
262     switch(EXTRACT_OP2(instr)) {
263     case 167: /* stvehx */
264     alignmask = 0xFFFFFFFE;
265     break;
266     case 199: /* stvewx */
267     alignmask = 0xFFFFFFFC;
268     break;
269     case 231: /* stvx */
270     alignmask = 0xFFFFFFF0;
271     break;
272     case 487: /* stvxl */
273     alignmask = 0xFFFFFFF0;
274     break;
275     }
276     break;
277     case 725: /* stswi */
278     tmp = EXTRACT_REGA(instr);
279     if(tmp > 0)
280     baseA = regs[tmp];
281     break;
282     default: /* ignore instruction */
283     return 0;
284     break;
285     }
286     break;
287     default: /* ignore instruction */
288     return 0;
289     break;
290     }
291    
292     addr = (baseA + baseB) + disp;
293     addr &= alignmask;
294     return (sigsegv_address_t)addr;
295     }
296     #endif
297     #endif
298 gbeauche 1.1 #endif
299    
300 gbeauche 1.10 #ifdef HAVE_SIGSEGV_SKIP_INSTRUCTION
301     // Decode and skip X86 instruction
302     #if (defined(i386) || defined(__i386__))
303     #if defined(__linux__)
304     enum {
305     X86_REG_EIP = 14,
306     X86_REG_EAX = 11,
307     X86_REG_ECX = 10,
308     X86_REG_EDX = 9,
309     X86_REG_EBX = 8,
310     X86_REG_ESP = 7,
311     X86_REG_EBP = 6,
312     X86_REG_ESI = 5,
313     X86_REG_EDI = 4
314     };
315     #endif
316     // FIXME: this is partly redundant with the instruction decoding phase
317     // to discover transfer type and register number
318     static inline int ix86_step_over_modrm(unsigned char * p)
319     {
320     int mod = (p[0] >> 6) & 3;
321     int rm = p[0] & 7;
322     int offset = 0;
323    
324     // ModR/M Byte
325     switch (mod) {
326     case 0: // [reg]
327     if (rm == 5) return 4; // disp32
328     break;
329     case 1: // disp8[reg]
330     offset = 1;
331     break;
332     case 2: // disp32[reg]
333     offset = 4;
334     break;
335     case 3: // register
336     return 0;
337     }
338    
339     // SIB Byte
340     if (rm == 4) {
341     if (mod == 0 && (p[1] & 7) == 5)
342     offset = 5; // disp32[index]
343     else
344     offset++;
345     }
346    
347     return offset;
348     }
349    
350     static bool ix86_skip_instruction(sigsegv_address_t fault_instruction, unsigned long * regs)
351     {
352     unsigned char * eip = (unsigned char *)fault_instruction;
353    
354     if (eip == 0)
355     return false;
356    
357     // Transfer type
358     enum {
359     TYPE_UNKNOWN,
360     TYPE_LOAD,
361     TYPE_STORE
362     } transfer_type = TYPE_UNKNOWN;
363    
364     // Transfer size
365     enum {
366     SIZE_BYTE,
367     SIZE_WORD,
368     SIZE_LONG
369     } transfer_size = SIZE_LONG;
370    
371     int reg = -1;
372     int len = 0;
373    
374     // Operand size prefix
375     if (*eip == 0x66) {
376     eip++;
377     len++;
378     transfer_size = SIZE_WORD;
379     }
380    
381     // Decode instruction
382     switch (eip[0]) {
383     case 0x8a: // MOV r8, r/m8
384     transfer_size = SIZE_BYTE;
385     case 0x8b: // MOV r32, r/m32 (or 16-bit operation)
386     switch (eip[1] & 0xc0) {
387     case 0x80:
388     reg = (eip[1] >> 3) & 7;
389     transfer_type = TYPE_LOAD;
390     break;
391     case 0x40:
392     reg = (eip[1] >> 3) & 7;
393     transfer_type = TYPE_LOAD;
394     break;
395     case 0x00:
396     reg = (eip[1] >> 3) & 7;
397     transfer_type = TYPE_LOAD;
398     break;
399     }
400     len += 2 + ix86_step_over_modrm(eip + 1);
401     break;
402     case 0x88: // MOV r/m8, r8
403     transfer_size = SIZE_BYTE;
404     case 0x89: // MOV r/m32, r32 (or 16-bit operation)
405     switch (eip[1] & 0xc0) {
406     case 0x80:
407     reg = (eip[1] >> 3) & 7;
408     transfer_type = TYPE_STORE;
409     break;
410     case 0x40:
411     reg = (eip[1] >> 3) & 7;
412     transfer_type = TYPE_STORE;
413     break;
414     case 0x00:
415     reg = (eip[1] >> 3) & 7;
416     transfer_type = TYPE_STORE;
417     break;
418     }
419     len += 2 + ix86_step_over_modrm(eip + 1);
420     break;
421     }
422    
423     if (transfer_type == TYPE_UNKNOWN) {
424     // Unknown machine code, let it crash. Then patch the decoder
425     return false;
426     }
427    
428     if (transfer_type == TYPE_LOAD && reg != -1) {
429     static const int x86_reg_map[8] = {
430     X86_REG_EAX, X86_REG_ECX, X86_REG_EDX, X86_REG_EBX,
431     X86_REG_ESP, X86_REG_EBP, X86_REG_ESI, X86_REG_EDI
432     };
433    
434     if (reg < 0 || reg >= 8)
435     return false;
436    
437     int rloc = x86_reg_map[reg];
438     switch (transfer_size) {
439     case SIZE_BYTE:
440     regs[rloc] = (regs[rloc] & ~0xff);
441     break;
442     case SIZE_WORD:
443     regs[rloc] = (regs[rloc] & ~0xffff);
444     break;
445     case SIZE_LONG:
446     regs[rloc] = 0;
447     break;
448     }
449     }
450    
451     #if DEBUG
452 gbeauche 1.13 printf("%08x: %s %s access", fault_instruction,
453 gbeauche 1.10 transfer_size == SIZE_BYTE ? "byte" : transfer_size == SIZE_WORD ? "word" : "long",
454     transfer_type == TYPE_LOAD ? "read" : "write");
455    
456     if (reg != -1) {
457     static const char * x86_reg_str_map[8] = {
458     "eax", "ecx", "edx", "ebx",
459     "esp", "ebp", "esi", "edi"
460     };
461     printf(" %s register %%%s", transfer_type == TYPE_LOAD ? "to" : "from", x86_reg_str_map[reg]);
462     }
463     printf(", %d bytes instruction\n", len);
464     #endif
465    
466     regs[X86_REG_EIP] += len;
467 gbeauche 1.13 return true;
468     }
469     #endif
470     // Decode and skip PPC instruction
471     #if (defined(powerpc) || defined(__powerpc__))
472     #if defined(__linux__)
473     enum {
474     POWERPC_REG_GPR = 0,
475     POWERPC_REG_NIP = 32
476     };
477     #endif
478     static bool powerpc_skip_instruction(sigsegv_address_t fault_instruction, unsigned long * regs)
479     {
480     // Get opcode and divide into fields
481     unsigned int opcode = *((unsigned int *)fault_instruction);
482     unsigned int primop = opcode >> 26;
483     unsigned int exop = (opcode >> 1) & 0x3ff;
484     unsigned int ra = (opcode >> 16) & 0x1f;
485     unsigned int rb = (opcode >> 11) & 0x1f;
486     unsigned int rd = (opcode >> 21) & 0x1f;
487     signed int imm = (signed short)(opcode & 0xffff);
488    
489     // Analyze opcode
490     enum {
491     TYPE_UNKNOWN,
492     TYPE_LOAD,
493     TYPE_STORE
494     } transfer_type = TYPE_UNKNOWN;
495     enum {
496     SIZE_UNKNOWN,
497     SIZE_BYTE,
498     SIZE_HALFWORD,
499     SIZE_WORD
500     } transfer_size = SIZE_UNKNOWN;
501     enum {
502     MODE_UNKNOWN,
503     MODE_NORM,
504     MODE_U,
505     MODE_X,
506     MODE_UX
507     } addr_mode = MODE_UNKNOWN;
508     switch (primop) {
509     case 31:
510     switch (exop) {
511     case 23: // lwzx
512     transfer_type = TYPE_LOAD; transfer_size = SIZE_WORD; addr_mode = MODE_X; break;
513     case 55: // lwzux
514     transfer_type = TYPE_LOAD; transfer_size = SIZE_WORD; addr_mode = MODE_UX; break;
515     case 87: // lbzx
516     transfer_type = TYPE_LOAD; transfer_size = SIZE_BYTE; addr_mode = MODE_X; break;
517     case 119: // lbzux
518     transfer_type = TYPE_LOAD; transfer_size = SIZE_BYTE; addr_mode = MODE_UX; break;
519     case 151: // stwx
520     transfer_type = TYPE_STORE; transfer_size = SIZE_WORD; addr_mode = MODE_X; break;
521     case 183: // stwux
522     transfer_type = TYPE_STORE; transfer_size = SIZE_WORD; addr_mode = MODE_UX; break;
523     case 215: // stbx
524     transfer_type = TYPE_STORE; transfer_size = SIZE_BYTE; addr_mode = MODE_X; break;
525     case 247: // stbux
526     transfer_type = TYPE_STORE; transfer_size = SIZE_BYTE; addr_mode = MODE_UX; break;
527     case 279: // lhzx
528     transfer_type = TYPE_LOAD; transfer_size = SIZE_HALFWORD; addr_mode = MODE_X; break;
529     case 311: // lhzux
530     transfer_type = TYPE_LOAD; transfer_size = SIZE_HALFWORD; addr_mode = MODE_UX; break;
531     case 343: // lhax
532     transfer_type = TYPE_LOAD; transfer_size = SIZE_HALFWORD; addr_mode = MODE_X; break;
533     case 375: // lhaux
534     transfer_type = TYPE_LOAD; transfer_size = SIZE_HALFWORD; addr_mode = MODE_UX; break;
535     case 407: // sthx
536     transfer_type = TYPE_STORE; transfer_size = SIZE_HALFWORD; addr_mode = MODE_X; break;
537     case 439: // sthux
538     transfer_type = TYPE_STORE; transfer_size = SIZE_HALFWORD; addr_mode = MODE_UX; break;
539     }
540     break;
541    
542     case 32: // lwz
543     transfer_type = TYPE_LOAD; transfer_size = SIZE_WORD; addr_mode = MODE_NORM; break;
544     case 33: // lwzu
545     transfer_type = TYPE_LOAD; transfer_size = SIZE_WORD; addr_mode = MODE_U; break;
546     case 34: // lbz
547     transfer_type = TYPE_LOAD; transfer_size = SIZE_BYTE; addr_mode = MODE_NORM; break;
548     case 35: // lbzu
549     transfer_type = TYPE_LOAD; transfer_size = SIZE_BYTE; addr_mode = MODE_U; break;
550     case 36: // stw
551     transfer_type = TYPE_STORE; transfer_size = SIZE_WORD; addr_mode = MODE_NORM; break;
552     case 37: // stwu
553     transfer_type = TYPE_STORE; transfer_size = SIZE_WORD; addr_mode = MODE_U; break;
554     case 38: // stb
555     transfer_type = TYPE_STORE; transfer_size = SIZE_BYTE; addr_mode = MODE_NORM; break;
556     case 39: // stbu
557     transfer_type = TYPE_STORE; transfer_size = SIZE_BYTE; addr_mode = MODE_U; break;
558     case 40: // lhz
559     transfer_type = TYPE_LOAD; transfer_size = SIZE_HALFWORD; addr_mode = MODE_NORM; break;
560     case 41: // lhzu
561     transfer_type = TYPE_LOAD; transfer_size = SIZE_HALFWORD; addr_mode = MODE_U; break;
562     case 42: // lha
563     transfer_type = TYPE_LOAD; transfer_size = SIZE_HALFWORD; addr_mode = MODE_NORM; break;
564     case 43: // lhau
565     transfer_type = TYPE_LOAD; transfer_size = SIZE_HALFWORD; addr_mode = MODE_U; break;
566     case 44: // sth
567     transfer_type = TYPE_STORE; transfer_size = SIZE_HALFWORD; addr_mode = MODE_NORM; break;
568     case 45: // sthu
569     transfer_type = TYPE_STORE; transfer_size = SIZE_HALFWORD; addr_mode = MODE_U; break;
570     }
571    
572     // Calculate effective address
573     unsigned int addr = 0;
574     switch (addr_mode) {
575     case MODE_X:
576     case MODE_UX:
577     if (ra == 0)
578     addr = regs[POWERPC_REG_GPR + rb];
579     else
580     addr = regs[POWERPC_REG_GPR + ra] + regs[POWERPC_REG_GPR + rb];
581     break;
582     case MODE_NORM:
583     case MODE_U:
584     if (ra == 0)
585     addr = (signed int)(signed short)imm;
586     else
587     addr = regs[POWERPC_REG_GPR + ra] + (signed int)(signed short)imm;
588     break;
589     default:
590     break;
591     }
592    
593     if (transfer_type == TYPE_UNKNOWN) {
594     // Unknown machine code, let it crash. Then patch the decoder
595     return false;
596     }
597    
598     #if DEBUG
599     printf("%08x: %s %s access", fault_instruction,
600     transfer_size == SIZE_BYTE ? "byte" : transfer_size == SIZE_HALFWORD ? "word" : "long",
601     transfer_type == TYPE_LOAD ? "read" : "write");
602    
603     if (addr_mode == MODE_U || addr_mode == MODE_UX)
604     printf(" r%d (ra = %08x)\n", ra, addr);
605     if (transfer_type == TYPE_LOAD)
606     printf(" r%d (rd = 0)\n", rd);
607     #endif
608    
609     if (addr_mode == MODE_U || addr_mode == MODE_UX)
610     regs[POWERPC_REG_GPR + ra] = addr;
611     if (transfer_type == TYPE_LOAD)
612     regs[POWERPC_REG_GPR + rd] = 0;
613    
614     regs[POWERPC_REG_NIP] += 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     if (SIGSEGV_SKIP_INSTRUCTION(fault_instruction, SIGSEGV_REGISTER_FILE))
653     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     if (vm_protect((char *)page, page_size, VM_PAGE_WRITE) < 0)
821     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