| 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 |
* |
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* Basilisk II (C) 1997-2002 Christian Bauer |
| 8 |
* |
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* 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. |
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* |
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* 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 |
|
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#ifdef HAVE_UNISTD_H |
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#include <unistd.h> |
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#endif |
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|
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#ifdef HAVE_CONFIG_H |
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#include "config.h" |
| 30 |
#endif |
| 31 |
|
| 32 |
#include <list> |
| 33 |
#include <signal.h> |
| 34 |
#include "sigsegv.h" |
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|
| 36 |
#ifndef NO_STD_NAMESPACE |
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using std::list; |
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#endif |
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|
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// Return value type of a signal handler (standard type if not defined) |
| 41 |
#ifndef RETSIGTYPE |
| 42 |
#define RETSIGTYPE void |
| 43 |
#endif |
| 44 |
|
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// Type of the system signal handler |
| 46 |
typedef RETSIGTYPE (*signal_handler)(int); |
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|
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// User's SIGSEGV handler |
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static sigsegv_fault_handler_t sigsegv_fault_handler = 0; |
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|
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// Function called to dump state if we can't handle the fault |
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static sigsegv_state_dumper_t sigsegv_state_dumper = 0; |
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|
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// Actual SIGSEGV handler installer |
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static bool sigsegv_do_install_handler(int sig); |
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|
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|
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/* |
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* Instruction decoding aids |
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*/ |
| 61 |
|
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// Transfer size |
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enum transfer_size_t { |
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SIZE_UNKNOWN, |
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SIZE_BYTE, |
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SIZE_WORD, |
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SIZE_LONG |
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}; |
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|
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// Transfer type |
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typedef sigsegv_transfer_type_t transfer_type_t; |
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|
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#if (defined(powerpc) || defined(__powerpc__) || defined(__ppc__)) |
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// Addressing mode |
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enum addressing_mode_t { |
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MODE_UNKNOWN, |
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MODE_NORM, |
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MODE_U, |
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MODE_X, |
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MODE_UX |
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}; |
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|
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// Decoded instruction |
| 84 |
struct instruction_t { |
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transfer_type_t transfer_type; |
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transfer_size_t transfer_size; |
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addressing_mode_t addr_mode; |
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unsigned int addr; |
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char ra, rd; |
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}; |
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|
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static void powerpc_decode_instruction(instruction_t *instruction, unsigned int nip, unsigned int * gpr) |
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{ |
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// Get opcode and divide into fields |
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unsigned int opcode = *((unsigned int *)nip); |
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unsigned int primop = opcode >> 26; |
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unsigned int exop = (opcode >> 1) & 0x3ff; |
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unsigned int ra = (opcode >> 16) & 0x1f; |
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unsigned int rb = (opcode >> 11) & 0x1f; |
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unsigned int rd = (opcode >> 21) & 0x1f; |
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signed int imm = (signed short)(opcode & 0xffff); |
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|
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// Analyze opcode |
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transfer_type_t transfer_type = SIGSEGV_TRANSFER_UNKNOWN; |
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transfer_size_t transfer_size = SIZE_UNKNOWN; |
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addressing_mode_t addr_mode = MODE_UNKNOWN; |
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switch (primop) { |
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case 31: |
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switch (exop) { |
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case 23: // lwzx |
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transfer_type = SIGSEGV_TRANSFER_LOAD; transfer_size = SIZE_LONG; addr_mode = MODE_X; break; |
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case 55: // lwzux |
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transfer_type = SIGSEGV_TRANSFER_LOAD; transfer_size = SIZE_LONG; addr_mode = MODE_UX; break; |
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case 87: // lbzx |
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transfer_type = SIGSEGV_TRANSFER_LOAD; transfer_size = SIZE_BYTE; addr_mode = MODE_X; break; |
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case 119: // lbzux |
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transfer_type = SIGSEGV_TRANSFER_LOAD; transfer_size = SIZE_BYTE; addr_mode = MODE_UX; break; |
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case 151: // stwx |
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transfer_type = SIGSEGV_TRANSFER_STORE; transfer_size = SIZE_LONG; addr_mode = MODE_X; break; |
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case 183: // stwux |
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transfer_type = SIGSEGV_TRANSFER_STORE; transfer_size = SIZE_LONG; addr_mode = MODE_UX; break; |
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case 215: // stbx |
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transfer_type = SIGSEGV_TRANSFER_STORE; transfer_size = SIZE_BYTE; addr_mode = MODE_X; break; |
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case 247: // stbux |
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transfer_type = SIGSEGV_TRANSFER_STORE; transfer_size = SIZE_BYTE; addr_mode = MODE_UX; break; |
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case 279: // lhzx |
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transfer_type = SIGSEGV_TRANSFER_LOAD; transfer_size = SIZE_WORD; addr_mode = MODE_X; break; |
| 128 |
case 311: // lhzux |
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transfer_type = SIGSEGV_TRANSFER_LOAD; transfer_size = SIZE_WORD; addr_mode = MODE_UX; break; |
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case 343: // lhax |
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transfer_type = SIGSEGV_TRANSFER_LOAD; transfer_size = SIZE_WORD; addr_mode = MODE_X; break; |
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case 375: // lhaux |
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transfer_type = SIGSEGV_TRANSFER_LOAD; transfer_size = SIZE_WORD; addr_mode = MODE_UX; break; |
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case 407: // sthx |
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transfer_type = SIGSEGV_TRANSFER_STORE; transfer_size = SIZE_WORD; addr_mode = MODE_X; break; |
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case 439: // sthux |
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transfer_type = SIGSEGV_TRANSFER_STORE; transfer_size = SIZE_WORD; addr_mode = MODE_UX; break; |
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} |
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break; |
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|
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case 32: // lwz |
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transfer_type = SIGSEGV_TRANSFER_LOAD; transfer_size = SIZE_LONG; addr_mode = MODE_NORM; break; |
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case 33: // lwzu |
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transfer_type = SIGSEGV_TRANSFER_LOAD; transfer_size = SIZE_LONG; addr_mode = MODE_U; break; |
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case 34: // lbz |
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transfer_type = SIGSEGV_TRANSFER_LOAD; transfer_size = SIZE_BYTE; addr_mode = MODE_NORM; break; |
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case 35: // lbzu |
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transfer_type = SIGSEGV_TRANSFER_LOAD; transfer_size = SIZE_BYTE; addr_mode = MODE_U; break; |
| 149 |
case 36: // stw |
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transfer_type = SIGSEGV_TRANSFER_STORE; transfer_size = SIZE_LONG; addr_mode = MODE_NORM; break; |
| 151 |
case 37: // stwu |
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transfer_type = SIGSEGV_TRANSFER_STORE; transfer_size = SIZE_LONG; addr_mode = MODE_U; break; |
| 153 |
case 38: // stb |
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transfer_type = SIGSEGV_TRANSFER_STORE; transfer_size = SIZE_BYTE; addr_mode = MODE_NORM; break; |
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case 39: // stbu |
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transfer_type = SIGSEGV_TRANSFER_STORE; transfer_size = SIZE_BYTE; addr_mode = MODE_U; break; |
| 157 |
case 40: // lhz |
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transfer_type = SIGSEGV_TRANSFER_LOAD; transfer_size = SIZE_WORD; addr_mode = MODE_NORM; break; |
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case 41: // lhzu |
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transfer_type = SIGSEGV_TRANSFER_LOAD; transfer_size = SIZE_WORD; addr_mode = MODE_U; break; |
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case 42: // lha |
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transfer_type = SIGSEGV_TRANSFER_LOAD; transfer_size = SIZE_WORD; addr_mode = MODE_NORM; break; |
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case 43: // lhau |
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transfer_type = SIGSEGV_TRANSFER_LOAD; transfer_size = SIZE_WORD; addr_mode = MODE_U; break; |
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case 44: // sth |
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transfer_type = SIGSEGV_TRANSFER_STORE; transfer_size = SIZE_WORD; addr_mode = MODE_NORM; break; |
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case 45: // sthu |
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transfer_type = SIGSEGV_TRANSFER_STORE; transfer_size = SIZE_WORD; addr_mode = MODE_U; break; |
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} |
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|
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// Calculate effective address |
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unsigned int addr = 0; |
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switch (addr_mode) { |
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case MODE_X: |
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case MODE_UX: |
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if (ra == 0) |
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addr = gpr[rb]; |
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else |
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addr = gpr[ra] + gpr[rb]; |
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break; |
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case MODE_NORM: |
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case MODE_U: |
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if (ra == 0) |
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addr = (signed int)(signed short)imm; |
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else |
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addr = gpr[ra] + (signed int)(signed short)imm; |
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break; |
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default: |
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break; |
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} |
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|
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// Commit decoded instruction |
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instruction->addr = addr; |
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instruction->addr_mode = addr_mode; |
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instruction->transfer_type = transfer_type; |
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instruction->transfer_size = transfer_size; |
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instruction->ra = ra; |
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instruction->rd = rd; |
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} |
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#endif |
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|
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|
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/* |
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* OS-dependant SIGSEGV signals support section |
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*/ |
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|
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#if HAVE_SIGINFO_T |
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// Generic extended signal handler |
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#if defined(__NetBSD__) || defined(__FreeBSD__) |
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#define SIGSEGV_ALL_SIGNALS FAULT_HANDLER(SIGBUS) |
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#else |
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#define SIGSEGV_ALL_SIGNALS FAULT_HANDLER(SIGSEGV) |
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#endif |
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#define SIGSEGV_FAULT_HANDLER_ARGLIST int sig, siginfo_t *sip, void *scp |
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#define SIGSEGV_FAULT_ADDRESS sip->si_addr |
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#if defined(__NetBSD__) || defined(__FreeBSD__) |
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#if (defined(i386) || defined(__i386__)) |
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#define SIGSEGV_FAULT_INSTRUCTION (((struct sigcontext *)scp)->sc_eip) |
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#define SIGSEGV_REGISTER_FILE ((unsigned int *)&(((struct sigcontext *)scp)->sc_edi)) /* EDI is the first GPR (even below EIP) in sigcontext */ |
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#define SIGSEGV_SKIP_INSTRUCTION ix86_skip_instruction |
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#endif |
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#endif |
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#if defined(__linux__) |
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#if (defined(i386) || defined(__i386__)) |
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#include <sys/ucontext.h> |
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#define SIGSEGV_CONTEXT_REGS (((ucontext_t *)scp)->uc_mcontext.gregs) |
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#define SIGSEGV_FAULT_INSTRUCTION SIGSEGV_CONTEXT_REGS[14] /* should use REG_EIP instead */ |
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#define SIGSEGV_REGISTER_FILE (unsigned int *)SIGSEGV_CONTEXT_REGS |
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#define SIGSEGV_SKIP_INSTRUCTION ix86_skip_instruction |
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#endif |
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#if (defined(x86_64) || defined(__x86_64__)) |
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#include <sys/ucontext.h> |
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#define SIGSEGV_CONTEXT_REGS (((ucontext_t *)scp)->uc_mcontext.gregs) |
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#define SIGSEGV_FAULT_INSTRUCTION SIGSEGV_CONTEXT_REGS[16] /* should use REG_RIP instead */ |
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#define SIGSEGV_REGISTER_FILE (unsigned long *)SIGSEGV_CONTEXT_REGS |
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#endif |
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#if (defined(ia64) || defined(__ia64__)) |
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#define SIGSEGV_FAULT_INSTRUCTION (((struct sigcontext *)scp)->sc_ip & ~0x3ULL) /* slot number is in bits 0 and 1 */ |
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#endif |
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#if (defined(powerpc) || defined(__powerpc__)) |
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#include <sys/ucontext.h> |
| 242 |
#define SIGSEGV_CONTEXT_REGS (((ucontext_t *)scp)->uc_mcontext.regs) |
| 243 |
#define SIGSEGV_FAULT_INSTRUCTION (SIGSEGV_CONTEXT_REGS->nip) |
| 244 |
#define SIGSEGV_REGISTER_FILE (unsigned int *)&SIGSEGV_CONTEXT_REGS->nip, (unsigned int *)(SIGSEGV_CONTEXT_REGS->gpr) |
| 245 |
#define SIGSEGV_SKIP_INSTRUCTION powerpc_skip_instruction |
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#endif |
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#endif |
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#endif |
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|
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#if HAVE_SIGCONTEXT_SUBTERFUGE |
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// Linux kernels prior to 2.4 ? |
| 252 |
#if defined(__linux__) |
| 253 |
#define SIGSEGV_ALL_SIGNALS FAULT_HANDLER(SIGSEGV) |
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#if (defined(i386) || defined(__i386__)) |
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#include <asm/sigcontext.h> |
| 256 |
#define SIGSEGV_FAULT_HANDLER_ARGLIST int sig, struct sigcontext scs |
| 257 |
#define SIGSEGV_FAULT_ADDRESS scs.cr2 |
| 258 |
#define SIGSEGV_FAULT_INSTRUCTION scs.eip |
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#define SIGSEGV_REGISTER_FILE (unsigned int *)(&scs) |
| 260 |
#define SIGSEGV_SKIP_INSTRUCTION ix86_skip_instruction |
| 261 |
#endif |
| 262 |
#if (defined(sparc) || defined(__sparc__)) |
| 263 |
#include <asm/sigcontext.h> |
| 264 |
#define SIGSEGV_FAULT_HANDLER_ARGLIST int sig, int code, struct sigcontext *scp, char *addr |
| 265 |
#define SIGSEGV_FAULT_ADDRESS addr |
| 266 |
#endif |
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#if (defined(powerpc) || defined(__powerpc__)) |
| 268 |
#include <asm/sigcontext.h> |
| 269 |
#define SIGSEGV_FAULT_HANDLER_ARGLIST int sig, struct sigcontext *scp |
| 270 |
#define SIGSEGV_FAULT_ADDRESS scp->regs->dar |
| 271 |
#define SIGSEGV_FAULT_INSTRUCTION scp->regs->nip |
| 272 |
#define SIGSEGV_REGISTER_FILE (unsigned int *)&scp->regs->nip, (unsigned int *)(scp->regs->gpr) |
| 273 |
#define SIGSEGV_SKIP_INSTRUCTION powerpc_skip_instruction |
| 274 |
#endif |
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#if (defined(alpha) || defined(__alpha__)) |
| 276 |
#include <asm/sigcontext.h> |
| 277 |
#define SIGSEGV_FAULT_HANDLER_ARGLIST int sig, int code, struct sigcontext *scp |
| 278 |
#define SIGSEGV_FAULT_ADDRESS get_fault_address(scp) |
| 279 |
#define SIGSEGV_FAULT_INSTRUCTION scp->sc_pc |
| 280 |
|
| 281 |
// From Boehm's GC 6.0alpha8 |
| 282 |
static sigsegv_address_t get_fault_address(struct sigcontext *scp) |
| 283 |
{ |
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unsigned int instruction = *((unsigned int *)(scp->sc_pc)); |
| 285 |
unsigned long fault_address = scp->sc_regs[(instruction >> 16) & 0x1f]; |
| 286 |
fault_address += (signed long)(signed short)(instruction & 0xffff); |
| 287 |
return (sigsegv_address_t)fault_address; |
| 288 |
} |
| 289 |
#endif |
| 290 |
#endif |
| 291 |
|
| 292 |
// Irix 5 or 6 on MIPS |
| 293 |
#if (defined(sgi) || defined(__sgi)) && (defined(SYSTYPE_SVR4) || defined(__SYSTYPE_SVR4)) |
| 294 |
#include <ucontext.h> |
| 295 |
#define SIGSEGV_FAULT_HANDLER_ARGLIST int sig, int code, struct sigcontext *scp |
| 296 |
#define SIGSEGV_FAULT_ADDRESS scp->sc_badvaddr |
| 297 |
#define SIGSEGV_ALL_SIGNALS FAULT_HANDLER(SIGSEGV) |
| 298 |
#endif |
| 299 |
|
| 300 |
// HP-UX |
| 301 |
#if (defined(hpux) || defined(__hpux__)) |
| 302 |
#define SIGSEGV_FAULT_HANDLER_ARGLIST int sig, int code, struct sigcontext *scp |
| 303 |
#define SIGSEGV_FAULT_ADDRESS scp->sc_sl.sl_ss.ss_narrow.ss_cr21 |
| 304 |
#define SIGSEGV_ALL_SIGNALS FAULT_HANDLER(SIGSEGV) FAULT_HANDLER(SIGBUS) |
| 305 |
#endif |
| 306 |
|
| 307 |
// OSF/1 on Alpha |
| 308 |
#if defined(__osf__) |
| 309 |
#include <ucontext.h> |
| 310 |
#define SIGSEGV_FAULT_HANDLER_ARGLIST int sig, int code, struct sigcontext *scp |
| 311 |
#define SIGSEGV_FAULT_ADDRESS scp->sc_traparg_a0 |
| 312 |
#define SIGSEGV_ALL_SIGNALS FAULT_HANDLER(SIGSEGV) |
| 313 |
#endif |
| 314 |
|
| 315 |
// AIX |
| 316 |
#if defined(_AIX) |
| 317 |
#define SIGSEGV_FAULT_HANDLER_ARGLIST int sig, int code, struct sigcontext *scp |
| 318 |
#define SIGSEGV_FAULT_ADDRESS scp->sc_jmpbuf.jmp_context.o_vaddr |
| 319 |
#define SIGSEGV_ALL_SIGNALS FAULT_HANDLER(SIGSEGV) |
| 320 |
#endif |
| 321 |
|
| 322 |
// NetBSD or FreeBSD |
| 323 |
#if defined(__NetBSD__) || defined(__FreeBSD__) |
| 324 |
#if (defined(m68k) || defined(__m68k__)) |
| 325 |
#include <m68k/frame.h> |
| 326 |
#define SIGSEGV_FAULT_HANDLER_ARGLIST int sig, int code, struct sigcontext *scp |
| 327 |
#define SIGSEGV_FAULT_ADDRESS get_fault_address(scp) |
| 328 |
#define SIGSEGV_ALL_SIGNALS FAULT_HANDLER(SIGSEGV) |
| 329 |
|
| 330 |
// Use decoding scheme from BasiliskII/m68k native |
| 331 |
static sigsegv_address_t get_fault_address(struct sigcontext *scp) |
| 332 |
{ |
| 333 |
struct sigstate { |
| 334 |
int ss_flags; |
| 335 |
struct frame ss_frame; |
| 336 |
}; |
| 337 |
struct sigstate *state = (struct sigstate *)scp->sc_ap; |
| 338 |
char *fault_addr; |
| 339 |
switch (state->ss_frame.f_format) { |
| 340 |
case 7: /* 68040 access error */ |
| 341 |
/* "code" is sometimes unreliable (i.e. contains NULL or a bogus address), reason unknown */ |
| 342 |
fault_addr = state->ss_frame.f_fmt7.f_fa; |
| 343 |
break; |
| 344 |
default: |
| 345 |
fault_addr = (char *)code; |
| 346 |
break; |
| 347 |
} |
| 348 |
return (sigsegv_address_t)fault_addr; |
| 349 |
} |
| 350 |
#else |
| 351 |
#define SIGSEGV_FAULT_HANDLER_ARGLIST int sig, int code, void *scp, char *addr |
| 352 |
#define SIGSEGV_FAULT_ADDRESS addr |
| 353 |
#define SIGSEGV_ALL_SIGNALS FAULT_HANDLER(SIGBUS) |
| 354 |
#endif |
| 355 |
#endif |
| 356 |
|
| 357 |
// MacOS X |
| 358 |
#if defined(__APPLE__) && defined(__MACH__) |
| 359 |
#if (defined(ppc) || defined(__ppc__)) |
| 360 |
#define SIGSEGV_FAULT_HANDLER_ARGLIST int sig, int code, struct sigcontext *scp |
| 361 |
#define SIGSEGV_FAULT_ADDRESS get_fault_address(scp) |
| 362 |
#define SIGSEGV_FAULT_INSTRUCTION scp->sc_ir |
| 363 |
#define SIGSEGV_ALL_SIGNALS FAULT_HANDLER(SIGBUS) |
| 364 |
#define SIGSEGV_REGISTER_FILE (unsigned int *)&scp->sc_ir, &((unsigned int *) scp->sc_regs)[2] |
| 365 |
#define SIGSEGV_SKIP_INSTRUCTION powerpc_skip_instruction |
| 366 |
|
| 367 |
// Use decoding scheme from SheepShaver |
| 368 |
static sigsegv_address_t get_fault_address(struct sigcontext *scp) |
| 369 |
{ |
| 370 |
unsigned int nip = (unsigned int) scp->sc_ir; |
| 371 |
unsigned int * gpr = &((unsigned int *) scp->sc_regs)[2]; |
| 372 |
instruction_t instr; |
| 373 |
|
| 374 |
powerpc_decode_instruction(&instr, nip, gpr); |
| 375 |
return (sigsegv_address_t)instr.addr; |
| 376 |
} |
| 377 |
#endif |
| 378 |
#endif |
| 379 |
#endif |
| 380 |
|
| 381 |
|
| 382 |
/* |
| 383 |
* Instruction skipping |
| 384 |
*/ |
| 385 |
|
| 386 |
#ifdef HAVE_SIGSEGV_SKIP_INSTRUCTION |
| 387 |
// Decode and skip X86 instruction |
| 388 |
#if (defined(i386) || defined(__i386__)) |
| 389 |
#if defined(__linux__) |
| 390 |
enum { |
| 391 |
X86_REG_EIP = 14, |
| 392 |
X86_REG_EAX = 11, |
| 393 |
X86_REG_ECX = 10, |
| 394 |
X86_REG_EDX = 9, |
| 395 |
X86_REG_EBX = 8, |
| 396 |
X86_REG_ESP = 7, |
| 397 |
X86_REG_EBP = 6, |
| 398 |
X86_REG_ESI = 5, |
| 399 |
X86_REG_EDI = 4 |
| 400 |
}; |
| 401 |
#endif |
| 402 |
#if defined(__NetBSD__) || defined(__FreeBSD__) |
| 403 |
enum { |
| 404 |
X86_REG_EIP = 10, |
| 405 |
X86_REG_EAX = 7, |
| 406 |
X86_REG_ECX = 6, |
| 407 |
X86_REG_EDX = 5, |
| 408 |
X86_REG_EBX = 4, |
| 409 |
X86_REG_ESP = 13, |
| 410 |
X86_REG_EBP = 2, |
| 411 |
X86_REG_ESI = 1, |
| 412 |
X86_REG_EDI = 0 |
| 413 |
}; |
| 414 |
#endif |
| 415 |
// FIXME: this is partly redundant with the instruction decoding phase |
| 416 |
// to discover transfer type and register number |
| 417 |
static inline int ix86_step_over_modrm(unsigned char * p) |
| 418 |
{ |
| 419 |
int mod = (p[0] >> 6) & 3; |
| 420 |
int rm = p[0] & 7; |
| 421 |
int offset = 0; |
| 422 |
|
| 423 |
// ModR/M Byte |
| 424 |
switch (mod) { |
| 425 |
case 0: // [reg] |
| 426 |
if (rm == 5) return 4; // disp32 |
| 427 |
break; |
| 428 |
case 1: // disp8[reg] |
| 429 |
offset = 1; |
| 430 |
break; |
| 431 |
case 2: // disp32[reg] |
| 432 |
offset = 4; |
| 433 |
break; |
| 434 |
case 3: // register |
| 435 |
return 0; |
| 436 |
} |
| 437 |
|
| 438 |
// SIB Byte |
| 439 |
if (rm == 4) { |
| 440 |
if (mod == 0 && (p[1] & 7) == 5) |
| 441 |
offset = 5; // disp32[index] |
| 442 |
else |
| 443 |
offset++; |
| 444 |
} |
| 445 |
|
| 446 |
return offset; |
| 447 |
} |
| 448 |
|
| 449 |
static bool ix86_skip_instruction(unsigned int * regs) |
| 450 |
{ |
| 451 |
unsigned char * eip = (unsigned char *)regs[X86_REG_EIP]; |
| 452 |
|
| 453 |
if (eip == 0) |
| 454 |
return false; |
| 455 |
|
| 456 |
transfer_type_t transfer_type = SIGSEGV_TRANSFER_UNKNOWN; |
| 457 |
transfer_size_t transfer_size = SIZE_LONG; |
| 458 |
|
| 459 |
int reg = -1; |
| 460 |
int len = 0; |
| 461 |
|
| 462 |
// Operand size prefix |
| 463 |
if (*eip == 0x66) { |
| 464 |
eip++; |
| 465 |
len++; |
| 466 |
transfer_size = SIZE_WORD; |
| 467 |
} |
| 468 |
|
| 469 |
// Decode instruction |
| 470 |
switch (eip[0]) { |
| 471 |
case 0x0f: |
| 472 |
switch (eip[1]) { |
| 473 |
case 0xb6: // MOVZX r32, r/m8 |
| 474 |
case 0xb7: // MOVZX r32, r/m16 |
| 475 |
switch (eip[2] & 0xc0) { |
| 476 |
case 0x80: |
| 477 |
reg = (eip[2] >> 3) & 7; |
| 478 |
transfer_type = SIGSEGV_TRANSFER_LOAD; |
| 479 |
break; |
| 480 |
case 0x40: |
| 481 |
reg = (eip[2] >> 3) & 7; |
| 482 |
transfer_type = SIGSEGV_TRANSFER_LOAD; |
| 483 |
break; |
| 484 |
case 0x00: |
| 485 |
reg = (eip[2] >> 3) & 7; |
| 486 |
transfer_type = SIGSEGV_TRANSFER_LOAD; |
| 487 |
break; |
| 488 |
} |
| 489 |
len += 3 + ix86_step_over_modrm(eip + 2); |
| 490 |
break; |
| 491 |
} |
| 492 |
break; |
| 493 |
case 0x8a: // MOV r8, r/m8 |
| 494 |
transfer_size = SIZE_BYTE; |
| 495 |
case 0x8b: // MOV r32, r/m32 (or 16-bit operation) |
| 496 |
switch (eip[1] & 0xc0) { |
| 497 |
case 0x80: |
| 498 |
reg = (eip[1] >> 3) & 7; |
| 499 |
transfer_type = SIGSEGV_TRANSFER_LOAD; |
| 500 |
break; |
| 501 |
case 0x40: |
| 502 |
reg = (eip[1] >> 3) & 7; |
| 503 |
transfer_type = SIGSEGV_TRANSFER_LOAD; |
| 504 |
break; |
| 505 |
case 0x00: |
| 506 |
reg = (eip[1] >> 3) & 7; |
| 507 |
transfer_type = SIGSEGV_TRANSFER_LOAD; |
| 508 |
break; |
| 509 |
} |
| 510 |
len += 2 + ix86_step_over_modrm(eip + 1); |
| 511 |
break; |
| 512 |
case 0x88: // MOV r/m8, r8 |
| 513 |
transfer_size = SIZE_BYTE; |
| 514 |
case 0x89: // MOV r/m32, r32 (or 16-bit operation) |
| 515 |
switch (eip[1] & 0xc0) { |
| 516 |
case 0x80: |
| 517 |
reg = (eip[1] >> 3) & 7; |
| 518 |
transfer_type = SIGSEGV_TRANSFER_STORE; |
| 519 |
break; |
| 520 |
case 0x40: |
| 521 |
reg = (eip[1] >> 3) & 7; |
| 522 |
transfer_type = SIGSEGV_TRANSFER_STORE; |
| 523 |
break; |
| 524 |
case 0x00: |
| 525 |
reg = (eip[1] >> 3) & 7; |
| 526 |
transfer_type = SIGSEGV_TRANSFER_STORE; |
| 527 |
break; |
| 528 |
} |
| 529 |
len += 2 + ix86_step_over_modrm(eip + 1); |
| 530 |
break; |
| 531 |
} |
| 532 |
|
| 533 |
if (transfer_type == SIGSEGV_TRANSFER_UNKNOWN) { |
| 534 |
// Unknown machine code, let it crash. Then patch the decoder |
| 535 |
return false; |
| 536 |
} |
| 537 |
|
| 538 |
if (transfer_type == SIGSEGV_TRANSFER_LOAD && reg != -1) { |
| 539 |
static const int x86_reg_map[8] = { |
| 540 |
X86_REG_EAX, X86_REG_ECX, X86_REG_EDX, X86_REG_EBX, |
| 541 |
X86_REG_ESP, X86_REG_EBP, X86_REG_ESI, X86_REG_EDI |
| 542 |
}; |
| 543 |
|
| 544 |
if (reg < 0 || reg >= 8) |
| 545 |
return false; |
| 546 |
|
| 547 |
int rloc = x86_reg_map[reg]; |
| 548 |
switch (transfer_size) { |
| 549 |
case SIZE_BYTE: |
| 550 |
regs[rloc] = (regs[rloc] & ~0xff); |
| 551 |
break; |
| 552 |
case SIZE_WORD: |
| 553 |
regs[rloc] = (regs[rloc] & ~0xffff); |
| 554 |
break; |
| 555 |
case SIZE_LONG: |
| 556 |
regs[rloc] = 0; |
| 557 |
break; |
| 558 |
} |
| 559 |
} |
| 560 |
|
| 561 |
#if DEBUG |
| 562 |
printf("%08x: %s %s access", regs[X86_REG_EIP], |
| 563 |
transfer_size == SIZE_BYTE ? "byte" : transfer_size == SIZE_WORD ? "word" : "long", |
| 564 |
transfer_type == SIGSEGV_TRANSFER_LOAD ? "read" : "write"); |
| 565 |
|
| 566 |
if (reg != -1) { |
| 567 |
static const char * x86_reg_str_map[8] = { |
| 568 |
"eax", "ecx", "edx", "ebx", |
| 569 |
"esp", "ebp", "esi", "edi" |
| 570 |
}; |
| 571 |
printf(" %s register %%%s", transfer_type == SIGSEGV_TRANSFER_LOAD ? "to" : "from", x86_reg_str_map[reg]); |
| 572 |
} |
| 573 |
printf(", %d bytes instruction\n", len); |
| 574 |
#endif |
| 575 |
|
| 576 |
regs[X86_REG_EIP] += len; |
| 577 |
return true; |
| 578 |
} |
| 579 |
#endif |
| 580 |
|
| 581 |
// Decode and skip PPC instruction |
| 582 |
#if (defined(powerpc) || defined(__powerpc__) || defined(__ppc__)) |
| 583 |
static bool powerpc_skip_instruction(unsigned int * nip_p, unsigned int * regs) |
| 584 |
{ |
| 585 |
instruction_t instr; |
| 586 |
powerpc_decode_instruction(&instr, *nip_p, regs); |
| 587 |
|
| 588 |
if (instr.transfer_type == SIGSEGV_TRANSFER_UNKNOWN) { |
| 589 |
// Unknown machine code, let it crash. Then patch the decoder |
| 590 |
return false; |
| 591 |
} |
| 592 |
|
| 593 |
#if DEBUG |
| 594 |
printf("%08x: %s %s access", *nip_p, |
| 595 |
instr.transfer_size == SIZE_BYTE ? "byte" : instr.transfer_size == SIZE_WORD ? "word" : "long", |
| 596 |
instr.transfer_type == SIGSEGV_TRANSFER_LOAD ? "read" : "write"); |
| 597 |
|
| 598 |
if (instr.addr_mode == MODE_U || instr.addr_mode == MODE_UX) |
| 599 |
printf(" r%d (ra = %08x)\n", instr.ra, instr.addr); |
| 600 |
if (instr.transfer_type == SIGSEGV_TRANSFER_LOAD) |
| 601 |
printf(" r%d (rd = 0)\n", instr.rd); |
| 602 |
#endif |
| 603 |
|
| 604 |
if (instr.addr_mode == MODE_U || instr.addr_mode == MODE_UX) |
| 605 |
regs[instr.ra] = instr.addr; |
| 606 |
if (instr.transfer_type == SIGSEGV_TRANSFER_LOAD) |
| 607 |
regs[instr.rd] = 0; |
| 608 |
|
| 609 |
*nip_p += 4; |
| 610 |
return true; |
| 611 |
} |
| 612 |
#endif |
| 613 |
#endif |
| 614 |
|
| 615 |
// Fallbacks |
| 616 |
#ifndef SIGSEGV_FAULT_INSTRUCTION |
| 617 |
#define SIGSEGV_FAULT_INSTRUCTION SIGSEGV_INVALID_PC |
| 618 |
#endif |
| 619 |
|
| 620 |
// SIGSEGV recovery supported ? |
| 621 |
#if defined(SIGSEGV_ALL_SIGNALS) && defined(SIGSEGV_FAULT_HANDLER_ARGLIST) && defined(SIGSEGV_FAULT_ADDRESS) |
| 622 |
#define HAVE_SIGSEGV_RECOVERY |
| 623 |
#endif |
| 624 |
|
| 625 |
|
| 626 |
/* |
| 627 |
* SIGSEGV global handler |
| 628 |
*/ |
| 629 |
|
| 630 |
#ifdef HAVE_SIGSEGV_RECOVERY |
| 631 |
static void sigsegv_handler(SIGSEGV_FAULT_HANDLER_ARGLIST) |
| 632 |
{ |
| 633 |
sigsegv_address_t fault_address = (sigsegv_address_t)SIGSEGV_FAULT_ADDRESS; |
| 634 |
sigsegv_address_t fault_instruction = (sigsegv_address_t)SIGSEGV_FAULT_INSTRUCTION; |
| 635 |
bool fault_recovered = false; |
| 636 |
|
| 637 |
// Call user's handler and reinstall the global handler, if required |
| 638 |
switch (sigsegv_fault_handler(fault_address, fault_instruction)) { |
| 639 |
case SIGSEGV_RETURN_SUCCESS: |
| 640 |
#if (defined(HAVE_SIGACTION) ? defined(SIGACTION_NEED_REINSTALL) : defined(SIGNAL_NEED_REINSTALL)) |
| 641 |
sigsegv_do_install_handler(sig); |
| 642 |
#endif |
| 643 |
fault_recovered = true; |
| 644 |
break; |
| 645 |
#if HAVE_SIGSEGV_SKIP_INSTRUCTION |
| 646 |
case SIGSEGV_RETURN_SKIP_INSTRUCTION: |
| 647 |
// Call the instruction skipper with the register file available |
| 648 |
if (SIGSEGV_SKIP_INSTRUCTION(SIGSEGV_REGISTER_FILE)) |
| 649 |
fault_recovered = true; |
| 650 |
break; |
| 651 |
#endif |
| 652 |
} |
| 653 |
|
| 654 |
if (!fault_recovered) { |
| 655 |
// Failure: reinstall default handler for "safe" crash |
| 656 |
#define FAULT_HANDLER(sig) signal(sig, SIG_DFL); |
| 657 |
SIGSEGV_ALL_SIGNALS |
| 658 |
#undef FAULT_HANDLER |
| 659 |
|
| 660 |
// We can't do anything with the fault_address, dump state? |
| 661 |
if (sigsegv_state_dumper != 0) |
| 662 |
sigsegv_state_dumper(fault_address, fault_instruction); |
| 663 |
} |
| 664 |
} |
| 665 |
#endif |
| 666 |
|
| 667 |
|
| 668 |
/* |
| 669 |
* SIGSEGV handler initialization |
| 670 |
*/ |
| 671 |
|
| 672 |
#if defined(HAVE_SIGINFO_T) |
| 673 |
static bool sigsegv_do_install_handler(int sig) |
| 674 |
{ |
| 675 |
// Setup SIGSEGV handler to process writes to frame buffer |
| 676 |
#ifdef HAVE_SIGACTION |
| 677 |
struct sigaction sigsegv_sa; |
| 678 |
sigemptyset(&sigsegv_sa.sa_mask); |
| 679 |
sigsegv_sa.sa_sigaction = sigsegv_handler; |
| 680 |
sigsegv_sa.sa_flags = SA_SIGINFO; |
| 681 |
return (sigaction(sig, &sigsegv_sa, 0) == 0); |
| 682 |
#else |
| 683 |
return (signal(sig, (signal_handler)sigsegv_handler) != SIG_ERR); |
| 684 |
#endif |
| 685 |
} |
| 686 |
#endif |
| 687 |
|
| 688 |
#if defined(HAVE_SIGCONTEXT_SUBTERFUGE) |
| 689 |
static bool sigsegv_do_install_handler(int sig) |
| 690 |
{ |
| 691 |
// Setup SIGSEGV handler to process writes to frame buffer |
| 692 |
#ifdef HAVE_SIGACTION |
| 693 |
struct sigaction sigsegv_sa; |
| 694 |
sigemptyset(&sigsegv_sa.sa_mask); |
| 695 |
sigsegv_sa.sa_handler = (signal_handler)sigsegv_handler; |
| 696 |
sigsegv_sa.sa_flags = 0; |
| 697 |
#if !EMULATED_68K && defined(__NetBSD__) |
| 698 |
sigaddset(&sigsegv_sa.sa_mask, SIGALRM); |
| 699 |
sigsegv_sa.sa_flags |= SA_ONSTACK; |
| 700 |
#endif |
| 701 |
return (sigaction(sig, &sigsegv_sa, 0) == 0); |
| 702 |
#else |
| 703 |
return (signal(sig, (signal_handler)sigsegv_handler) != SIG_ERR); |
| 704 |
#endif |
| 705 |
} |
| 706 |
#endif |
| 707 |
|
| 708 |
bool sigsegv_install_handler(sigsegv_fault_handler_t handler) |
| 709 |
{ |
| 710 |
#ifdef HAVE_SIGSEGV_RECOVERY |
| 711 |
sigsegv_fault_handler = handler; |
| 712 |
bool success = true; |
| 713 |
#define FAULT_HANDLER(sig) success = success && sigsegv_do_install_handler(sig); |
| 714 |
SIGSEGV_ALL_SIGNALS |
| 715 |
#undef FAULT_HANDLER |
| 716 |
return success; |
| 717 |
#else |
| 718 |
// FAIL: no siginfo_t nor sigcontext subterfuge is available |
| 719 |
return false; |
| 720 |
#endif |
| 721 |
} |
| 722 |
|
| 723 |
|
| 724 |
/* |
| 725 |
* SIGSEGV handler deinitialization |
| 726 |
*/ |
| 727 |
|
| 728 |
void sigsegv_deinstall_handler(void) |
| 729 |
{ |
| 730 |
#ifdef HAVE_SIGSEGV_RECOVERY |
| 731 |
sigsegv_fault_handler = 0; |
| 732 |
#define FAULT_HANDLER(sig) signal(sig, SIG_DFL); |
| 733 |
SIGSEGV_ALL_SIGNALS |
| 734 |
#undef FAULT_HANDLER |
| 735 |
#endif |
| 736 |
} |
| 737 |
|
| 738 |
|
| 739 |
/* |
| 740 |
* Set callback function when we cannot handle the fault |
| 741 |
*/ |
| 742 |
|
| 743 |
void sigsegv_set_dump_state(sigsegv_state_dumper_t handler) |
| 744 |
{ |
| 745 |
sigsegv_state_dumper = handler; |
| 746 |
} |
| 747 |
|
| 748 |
|
| 749 |
/* |
| 750 |
* Test program used for configure/test |
| 751 |
*/ |
| 752 |
|
| 753 |
#ifdef CONFIGURE_TEST_SIGSEGV_RECOVERY |
| 754 |
#include <stdio.h> |
| 755 |
#include <stdlib.h> |
| 756 |
#include <fcntl.h> |
| 757 |
#include <sys/mman.h> |
| 758 |
#include "vm_alloc.h" |
| 759 |
|
| 760 |
static int page_size; |
| 761 |
static volatile char * page = 0; |
| 762 |
static volatile int handler_called = 0; |
| 763 |
|
| 764 |
static sigsegv_return_t sigsegv_test_handler(sigsegv_address_t fault_address, sigsegv_address_t instruction_address) |
| 765 |
{ |
| 766 |
handler_called++; |
| 767 |
if ((fault_address - 123) != page) |
| 768 |
exit(1); |
| 769 |
if (vm_protect((char *)((unsigned long)fault_address & -page_size), page_size, VM_PAGE_READ | VM_PAGE_WRITE) != 0) |
| 770 |
exit(1); |
| 771 |
return SIGSEGV_RETURN_SUCCESS; |
| 772 |
} |
| 773 |
|
| 774 |
#ifdef HAVE_SIGSEGV_SKIP_INSTRUCTION |
| 775 |
static sigsegv_return_t sigsegv_insn_handler(sigsegv_address_t fault_address, sigsegv_address_t instruction_address) |
| 776 |
{ |
| 777 |
if (((unsigned long)fault_address - (unsigned long)page) < page_size) |
| 778 |
return SIGSEGV_RETURN_SKIP_INSTRUCTION; |
| 779 |
return SIGSEGV_RETURN_FAILURE; |
| 780 |
} |
| 781 |
#endif |
| 782 |
|
| 783 |
int main(void) |
| 784 |
{ |
| 785 |
if (vm_init() < 0) |
| 786 |
return 1; |
| 787 |
|
| 788 |
page_size = getpagesize(); |
| 789 |
if ((page = (char *)vm_acquire(page_size)) == VM_MAP_FAILED) |
| 790 |
return 1; |
| 791 |
|
| 792 |
if (vm_protect((char *)page, page_size, VM_PAGE_READ) < 0) |
| 793 |
return 1; |
| 794 |
|
| 795 |
if (!sigsegv_install_handler(sigsegv_test_handler)) |
| 796 |
return 1; |
| 797 |
|
| 798 |
page[123] = 45; |
| 799 |
page[123] = 45; |
| 800 |
|
| 801 |
if (handler_called != 1) |
| 802 |
return 1; |
| 803 |
|
| 804 |
#ifdef HAVE_SIGSEGV_SKIP_INSTRUCTION |
| 805 |
if (!sigsegv_install_handler(sigsegv_insn_handler)) |
| 806 |
return 1; |
| 807 |
|
| 808 |
if (vm_protect((char *)page, page_size, VM_PAGE_READ | VM_PAGE_WRITE) < 0) |
| 809 |
return 1; |
| 810 |
|
| 811 |
for (int i = 0; i < page_size; i++) |
| 812 |
page[i] = (i + 1) % page_size; |
| 813 |
|
| 814 |
if (vm_protect((char *)page, page_size, VM_PAGE_NOACCESS) < 0) |
| 815 |
return 1; |
| 816 |
|
| 817 |
#define TEST_SKIP_INSTRUCTION(TYPE) do { \ |
| 818 |
const unsigned int TAG = 0x12345678; \ |
| 819 |
TYPE data = *((TYPE *)(page + sizeof(TYPE))); \ |
| 820 |
volatile unsigned int effect = data + TAG; \ |
| 821 |
if (effect != TAG) \ |
| 822 |
return 1; \ |
| 823 |
} while (0) |
| 824 |
|
| 825 |
TEST_SKIP_INSTRUCTION(unsigned char); |
| 826 |
TEST_SKIP_INSTRUCTION(unsigned short); |
| 827 |
TEST_SKIP_INSTRUCTION(unsigned int); |
| 828 |
#endif |
| 829 |
|
| 830 |
vm_exit(); |
| 831 |
return 0; |
| 832 |
} |
| 833 |
#endif |
