Welcome to The Fiwix Project
Your small UNIX-like kernel
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1 /* 2 * fiwix/kernel/traps.c 3 * 4 * Copyright 2018-2022, Jordi Sanfeliu. All rights reserved. 5 * Distributed under the terms of the Fiwix License. 6 */ 7 8 #include <fiwix/asm.h> 9 #include <fiwix/kernel.h> 10 #include <fiwix/traps.h> 11 #include <fiwix/cpu.h> 12 #include <fiwix/mm.h> 13 #include <fiwix/process.h> 14 #include <fiwix/signal.h> 15 #include <fiwix/stdio.h> 16 #include <fiwix/string.h> 17 #include <fiwix/sched.h> 18 19 /* 20 * PS/2 System Control Port B 21 * --------------------------------------- 22 * bit 7 -> system board RAM parity check 23 * bit 6 -> channel check 24 * bit 5 -> timer 2 (speaker time) output 25 * bit 4 -> refresh request (toggle) 26 * bit 3 -> channel check status 27 * bit 2 -> parity check status 28 * bit 1 -> speaker data status 29 * bit 0 -> timer 2 gate to speaker status 30 */ 31 #define PS2_SYSCTRL_B 0x61 /* PS/2 system control port B (read) */ 32 33 struct traps traps_table[NR_EXCEPTIONS] = { 34 { "Divide Error", do_divide_error, 0 }, 35 { "Debug", do_debug, 0 }, 36 { "NMI Interrupt", do_nmi_interrupt, 0 }, 37 { "Breakpoint", do_breakpoint, 0 }, 38 { "Overflow" , do_overflow, 0 }, 39 { "BOUND Range Exceeded", do_bound, 0 }, 40 { "Invalid Opcode", do_invalid_opcode, 0 }, 41 { "Device Not Available (No Math Coprocessor)", do_no_math_coprocessor, 0 }, 42 { "Double Fault", do_double_fault, 1 }, 43 { "Coprocessor Segment Overrun", do_coprocessor_segment_overrun, 0 }, 44 { "Invalid TSS", do_invalid_tss, 1 }, 45 { "Segment Not Present", do_segment_not_present, 1 }, 46 { "Stack-Segment Fault", do_stack_segment_fault, 1 }, 47 { "General Protection", do_general_protection, 1 }, 48 { "Page Fault", do_page_fault, 1 }, 49 { "Intel reserved", do_reserved, 0 }, 50 { "x87 FPU Floating-Point Error", do_floating_point_error, 0 }, 51 { "Alignment Check", do_alignment_check, 1 }, 52 { "Machine Check", do_machine_check, 0 }, 53 { "SIMD Floating-Point Exception", do_simd_fault, 0 }, 54 { "Intel reserved", do_reserved, 0 }, 55 { "Intel reserved", do_reserved, 0 }, 56 { "Intel reserved", do_reserved, 0 }, 57 { "Intel reserved", do_reserved, 0 }, 58 { "Intel reserved", do_reserved, 0 }, 59 { "Intel reserved", do_reserved, 0 }, 60 { "Intel reserved", do_reserved, 0 }, 61 { "Intel reserved", do_reserved, 0 }, 62 { "Intel reserved", do_reserved, 0 }, 63 { "Intel reserved", do_reserved, 0 }, 64 { "Intel reserved", do_reserved, 0 }, 65 { "Intel reserved", do_reserved, 0 } 66 }; 67 68 void do_divide_error(unsigned int trap, struct sigcontext *sc) 69 { 70 if(dump_registers(trap, sc)) { 71 PANIC(""); 72 } 73 send_sig(current, SIGFPE); 74 return; 75 } 76 77 void do_debug(unsigned int trap, struct sigcontext *sc) 78 { 79 if(dump_registers(trap, sc)) { 80 PANIC(""); 81 } 82 send_sig(current, SIGTRAP); 83 return; 84 } 85 86 void do_nmi_interrupt(unsigned int trap, struct sigcontext *sc) 87 { 88 unsigned char error; 89 90 error = inport_b(PS2_SYSCTRL_B); 91 92 printk("NMI received: ", error); 93 switch(error) { 94 case 0x80: 95 printk("parity check occurred. Defective RAM chips?\n"); 96 break; 97 default: 98 printk("unknown error 0x%x\n", error); 99 break; 100 } 101 102 if(dump_registers(trap, sc)) { 103 PANIC(""); 104 } 105 send_sig(current, SIGSEGV); 106 return; 107 } 108 109 void do_breakpoint(unsigned int trap, struct sigcontext *sc) 110 { 111 if(dump_registers(trap, sc)) { 112 PANIC(""); 113 } 114 send_sig(current, SIGTRAP); 115 return; 116 } 117 118 void do_overflow(unsigned int trap, struct sigcontext *sc) 119 { 120 if(dump_registers(trap, sc)) { 121 PANIC(""); 122 } 123 send_sig(current, SIGSEGV); 124 return; 125 } 126 127 void do_bound(unsigned int trap, struct sigcontext *sc) 128 { 129 if(dump_registers(trap, sc)) { 130 PANIC(""); 131 } 132 send_sig(current, SIGSEGV); 133 return; 134 } 135 136 void do_invalid_opcode(unsigned int trap, struct sigcontext *sc) 137 { 138 if(dump_registers(trap, sc)) { 139 PANIC(""); 140 } 141 send_sig(current, SIGILL); 142 return; 143 } 144 145 void do_no_math_coprocessor(unsigned int trap, struct sigcontext *sc) 146 { 147 /* floating-point emulation would go here */ 148 149 if(dump_registers(trap, sc)) { 150 PANIC("No coprocessor/emulation found.\n"); 151 } 152 send_sig(current, SIGILL); 153 return; 154 } 155 156 void do_double_fault(unsigned int trap, struct sigcontext *sc) 157 { 158 if(dump_registers(trap, sc)) { 159 PANIC(""); 160 } 161 send_sig(current, SIGSEGV); 162 return; 163 } 164 165 void do_coprocessor_segment_overrun(unsigned int trap, struct sigcontext *sc) 166 { 167 if(dump_registers(trap, sc)) { 168 PANIC(""); 169 } 170 send_sig(current, SIGFPE); 171 return; 172 } 173 174 void do_invalid_tss(unsigned int trap, struct sigcontext *sc) 175 { 176 if(dump_registers(trap, sc)) { 177 PANIC(""); 178 } 179 send_sig(current, SIGSEGV); 180 return; 181 } 182 183 void do_segment_not_present(unsigned int trap, struct sigcontext *sc) 184 { 185 if(dump_registers(trap, sc)) { 186 PANIC(""); 187 } 188 send_sig(current, SIGBUS); 189 return; 190 } 191 192 void do_stack_segment_fault(unsigned int trap, struct sigcontext *sc) 193 { 194 if(dump_registers(trap, sc)) { 195 PANIC(""); 196 } 197 send_sig(current, SIGBUS); 198 return; 199 } 200 201 void do_general_protection(unsigned int trap, struct sigcontext *sc) 202 { 203 if(dump_registers(trap, sc)) { 204 PANIC(""); 205 } 206 send_sig(current, SIGSEGV); 207 return; 208 } 209 210 /* do_page_fault() resides in mm/fault.c */ 211 212 void do_reserved(unsigned int trap, struct sigcontext *sc) 213 { 214 if(dump_registers(trap, sc)) { 215 PANIC(""); 216 } 217 send_sig(current, SIGSEGV); 218 return; 219 } 220 221 void do_floating_point_error(unsigned int trap, struct sigcontext *sc) 222 { 223 if(dump_registers(trap, sc)) { 224 PANIC(""); 225 } 226 send_sig(current, SIGFPE); 227 return; 228 } 229 230 void do_alignment_check(unsigned int trap, struct sigcontext *sc) 231 { 232 if(dump_registers(trap, sc)) { 233 PANIC(""); 234 } 235 send_sig(current, SIGSEGV); 236 return; 237 } 238 239 void do_machine_check(unsigned int trap, struct sigcontext *sc) 240 { 241 if(dump_registers(trap, sc)) { 242 PANIC(""); 243 } 244 send_sig(current, SIGSEGV); 245 return; 246 } 247 248 void do_simd_fault(unsigned int trap, struct sigcontext *sc) 249 { 250 if(dump_registers(trap, sc)) { 251 PANIC(""); 252 } 253 send_sig(current, SIGSEGV); 254 return; 255 } 256 257 void trap_handler(unsigned int trap, struct sigcontext sc) 258 { 259 traps_table[trap].handler(trap, &sc); 260 261 /* avoids confusion with -RESTART return value */ 262 sc.err = -sc.err; 263 } 264 265 const char *elf_lookup_symbol(unsigned int addr) 266 { 267 Elf32_Sym *sym; 268 unsigned int n; 269 270 sym = (Elf32_Sym *)symtab->sh_addr; 271 for(n = 0; n < symtab->sh_size / sizeof(Elf32_Sym); n++, sym++) { 272 if(ELF32_ST_TYPE(sym->st_info) != STT_FUNC) { 273 continue; 274 } 275 if(addr >= sym->st_value && addr < (sym->st_value + sym->st_size)) { 276 return (const char *)strtab->sh_addr + sym->st_name; 277 } 278 } 279 return NULL; 280 } 281 282 void stack_backtrace(void) 283 { 284 int n; 285 unsigned int addr, *sp; 286 const char *str; 287 288 printk("Stack:\n"); 289 GET_ESP(sp); 290 sp = (unsigned int *)sp; 291 for(n = 1; n <= 32; n++) { 292 printk(" %08x", *sp); 293 sp++; 294 if(!(n % 8)) { 295 printk("\n"); 296 } 297 } 298 printk("Backtrace:\n"); 299 GET_ESP(sp); 300 sp = (unsigned int *)sp; 301 for(n = 0; n < 256; n++) { 302 addr = *sp; 303 str = elf_lookup_symbol(addr); 304 if(str) { 305 printk("<0x%08x> %s()\n", addr, str); 306 } 307 sp++; 308 } 309 } 310 311 int dump_registers(unsigned int trap, struct sigcontext *sc) 312 { 313 unsigned int cr2; 314 315 printk("\n"); 316 if(trap == 14) { /* Page Fault */ 317 GET_CR2(cr2); 318 printk("%s at 0x%08x (%s) with error code 0x%08x (0b%b)\n", traps_table[trap].name, cr2, sc->err & PFAULT_W ? "writing" : "reading", sc->err, sc->err); 319 } else { 320 printk("EXCEPTION: %s", traps_table[trap].name); 321 if(traps_table[trap].errcode) { 322 printk(": error code 0x%08x (0b%b)", sc->err, sc->err); 323 } 324 printk("\n"); 325 } 326 327 printk("Process '%s' with pid %d", current->argv0, current->pid); 328 if(sc->cs == KERNEL_CS) { 329 printk(" in '%s()'.", elf_lookup_symbol(sc->eip)); 330 } 331 printk("\n"); 332 333 printk(" cs: 0x%08x\teip: 0x%08x\tefl: 0x%08x\t ss: 0x%08x\tesp: 0x%08x\n", sc->cs, sc->eip, sc->eflags, sc->oldss, sc->oldesp); 334 printk("eax: 0x%08x\tebx: 0x%08x\tecx: 0x%08x\tedx: 0x%08x\n", sc->eax, sc->ebx, sc->ecx, sc->edx); 335 printk("esi: 0x%08x\tedi: 0x%08x\tesp: 0x%08x\tebp: 0x%08x\n", sc->esi, sc->edi, sc->esp, sc->ebp); 336 printk(" ds: 0x%08x\t es: 0x%08x\t fs: 0x%08x\t gs: 0x%08x\n", sc->ds, sc->es, sc->fs, sc->gs); 337 338 if(sc->cs == KERNEL_CS) { 339 stack_backtrace(); 340 } 341 342 /* panics if the exception has been in kernel mode */ 343 if(current->flags & PF_KPROC || sc->cs == KERNEL_CS) { 344 return 1; 345 } 346 347 return 0; 348 }
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