1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * OpenRISC traps.c 4 * 5 * Linux architectural port borrowing liberally from similar works of 6 * others. All original copyrights apply as per the original source 7 * declaration. 8 * 9 * Modifications for the OpenRISC architecture: 10 * Copyright (C) 2003 Matjaz Breskvar <phoenix@bsemi.com> 11 * Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se> 12 * 13 * Here we handle the break vectors not used by the system call 14 * mechanism, as well as some general stack/register dumping 15 * things. 16 */ 17 18 #include <linux/init.h> 19 #include <linux/sched.h> 20 #include <linux/sched/debug.h> 21 #include <linux/sched/task_stack.h> 22 #include <linux/kernel.h> 23 #include <linux/extable.h> 24 #include <linux/kmod.h> 25 #include <linux/string.h> 26 #include <linux/errno.h> 27 #include <linux/ptrace.h> 28 #include <linux/timer.h> 29 #include <linux/mm.h> 30 #include <linux/kallsyms.h> 31 #include <linux/uaccess.h> 32 33 #include <asm/bug.h> 34 #include <asm/io.h> 35 #include <asm/processor.h> 36 #include <asm/unwinder.h> 37 #include <asm/sections.h> 38 39 int lwa_flag; 40 static unsigned long __user *lwa_addr; 41 42 asmlinkage void unhandled_exception(struct pt_regs *regs, int ea, int vector); 43 asmlinkage void do_trap(struct pt_regs *regs, unsigned long address); 44 asmlinkage void do_fpe_trap(struct pt_regs *regs, unsigned long address); 45 asmlinkage void do_unaligned_access(struct pt_regs *regs, unsigned long address); 46 asmlinkage void do_bus_fault(struct pt_regs *regs, unsigned long address); 47 asmlinkage void do_illegal_instruction(struct pt_regs *regs, 48 unsigned long address); 49 50 static void print_trace(void *data, unsigned long addr, int reliable) 51 { 52 const char *loglvl = data; 53 54 printk("%s[<%p>] %s%pS\n", loglvl, (void *) addr, reliable ? "" : "? ", 55 (void *) addr); 56 } 57 58 static void print_data(unsigned long base_addr, unsigned long word, int i) 59 { 60 if (i == 0) 61 printk("(%08lx:)\t%08lx", base_addr + (i * 4), word); 62 else 63 printk(" %08lx:\t%08lx", base_addr + (i * 4), word); 64 } 65 66 /* displays a short stack trace */ 67 void show_stack(struct task_struct *task, unsigned long *esp, const char *loglvl) 68 { 69 if (esp == NULL) 70 esp = (unsigned long *)&esp; 71 72 printk("%sCall trace:\n", loglvl); 73 unwind_stack((void *)loglvl, esp, print_trace); 74 } 75 76 void show_registers(struct pt_regs *regs) 77 { 78 int i; 79 int in_kernel = 1; 80 unsigned long esp; 81 82 esp = (unsigned long)(regs->sp); 83 if (user_mode(regs)) 84 in_kernel = 0; 85 86 printk("CPU #: %d\n" 87 " PC: %08lx SR: %08lx SP: %08lx FPCSR: %08lx\n", 88 smp_processor_id(), regs->pc, regs->sr, regs->sp, 89 regs->fpcsr); 90 printk("GPR00: %08lx GPR01: %08lx GPR02: %08lx GPR03: %08lx\n", 91 0L, regs->gpr[1], regs->gpr[2], regs->gpr[3]); 92 printk("GPR04: %08lx GPR05: %08lx GPR06: %08lx GPR07: %08lx\n", 93 regs->gpr[4], regs->gpr[5], regs->gpr[6], regs->gpr[7]); 94 printk("GPR08: %08lx GPR09: %08lx GPR10: %08lx GPR11: %08lx\n", 95 regs->gpr[8], regs->gpr[9], regs->gpr[10], regs->gpr[11]); 96 printk("GPR12: %08lx GPR13: %08lx GPR14: %08lx GPR15: %08lx\n", 97 regs->gpr[12], regs->gpr[13], regs->gpr[14], regs->gpr[15]); 98 printk("GPR16: %08lx GPR17: %08lx GPR18: %08lx GPR19: %08lx\n", 99 regs->gpr[16], regs->gpr[17], regs->gpr[18], regs->gpr[19]); 100 printk("GPR20: %08lx GPR21: %08lx GPR22: %08lx GPR23: %08lx\n", 101 regs->gpr[20], regs->gpr[21], regs->gpr[22], regs->gpr[23]); 102 printk("GPR24: %08lx GPR25: %08lx GPR26: %08lx GPR27: %08lx\n", 103 regs->gpr[24], regs->gpr[25], regs->gpr[26], regs->gpr[27]); 104 printk("GPR28: %08lx GPR29: %08lx GPR30: %08lx GPR31: %08lx\n", 105 regs->gpr[28], regs->gpr[29], regs->gpr[30], regs->gpr[31]); 106 printk(" RES: %08lx oGPR11: %08lx\n", 107 regs->gpr[11], regs->orig_gpr11); 108 109 printk("Process %s (pid: %d, stackpage=%08lx)\n", 110 current->comm, current->pid, (unsigned long)current); 111 /* 112 * When in-kernel, we also print out the stack and code at the 113 * time of the fault.. 114 */ 115 if (in_kernel) { 116 117 printk("\nStack: "); 118 show_stack(NULL, (unsigned long *)esp, KERN_EMERG); 119 120 if (esp < PAGE_OFFSET) 121 goto bad_stack; 122 123 printk("\n"); 124 for (i = -8; i < 24; i += 1) { 125 unsigned long word; 126 127 if (__get_user(word, &((unsigned long *)esp)[i])) { 128 bad_stack: 129 printk(" Bad Stack value."); 130 break; 131 } 132 133 print_data(esp, word, i); 134 } 135 136 printk("\nCode: "); 137 if (regs->pc < PAGE_OFFSET) 138 goto bad; 139 140 for (i = -6; i < 6; i += 1) { 141 unsigned long word; 142 143 if (__get_user(word, &((unsigned long *)regs->pc)[i])) { 144 bad: 145 printk(" Bad PC value."); 146 break; 147 } 148 149 print_data(regs->pc, word, i); 150 } 151 } 152 printk("\n"); 153 } 154 155 /* This is normally the 'Oops' routine */ 156 void __noreturn die(const char *str, struct pt_regs *regs, long err) 157 { 158 159 console_verbose(); 160 printk("\n%s#: %04lx\n", str, err & 0xffff); 161 show_registers(regs); 162 #ifdef CONFIG_JUMP_UPON_UNHANDLED_EXCEPTION 163 printk("\n\nUNHANDLED_EXCEPTION: entering infinite loop\n"); 164 165 /* shut down interrupts */ 166 local_irq_disable(); 167 168 __asm__ __volatile__("l.nop 1"); 169 do {} while (1); 170 #endif 171 make_task_dead(SIGSEGV); 172 } 173 174 asmlinkage void unhandled_exception(struct pt_regs *regs, int ea, int vector) 175 { 176 printk("Unable to handle exception at EA =0x%x, vector 0x%x", 177 ea, vector); 178 die("Oops", regs, 9); 179 } 180 181 asmlinkage void do_fpe_trap(struct pt_regs *regs, unsigned long address) 182 { 183 int code = FPE_FLTUNK; 184 unsigned long fpcsr = regs->fpcsr; 185 186 if (fpcsr & SPR_FPCSR_IVF) 187 code = FPE_FLTINV; 188 else if (fpcsr & SPR_FPCSR_OVF) 189 code = FPE_FLTOVF; 190 else if (fpcsr & SPR_FPCSR_UNF) 191 code = FPE_FLTUND; 192 else if (fpcsr & SPR_FPCSR_DZF) 193 code = FPE_FLTDIV; 194 else if (fpcsr & SPR_FPCSR_IXF) 195 code = FPE_FLTRES; 196 197 /* Clear all flags */ 198 regs->fpcsr &= ~SPR_FPCSR_ALLF; 199 200 force_sig_fault(SIGFPE, code, (void __user *)regs->pc); 201 } 202 203 asmlinkage void do_trap(struct pt_regs *regs, unsigned long address) 204 { 205 force_sig_fault(SIGTRAP, TRAP_BRKPT, (void __user *)regs->pc); 206 } 207 208 asmlinkage void do_unaligned_access(struct pt_regs *regs, unsigned long address) 209 { 210 if (user_mode(regs)) { 211 /* Send a SIGBUS */ 212 force_sig_fault(SIGBUS, BUS_ADRALN, (void __user *)address); 213 } else { 214 printk("KERNEL: Unaligned Access 0x%.8lx\n", address); 215 show_registers(regs); 216 die("Die:", regs, address); 217 } 218 219 } 220 221 asmlinkage void do_bus_fault(struct pt_regs *regs, unsigned long address) 222 { 223 if (user_mode(regs)) { 224 /* Send a SIGBUS */ 225 force_sig_fault(SIGBUS, BUS_ADRERR, (void __user *)address); 226 } else { /* Kernel mode */ 227 printk("KERNEL: Bus error (SIGBUS) 0x%.8lx\n", address); 228 show_registers(regs); 229 die("Die:", regs, address); 230 } 231 } 232 233 static inline int in_delay_slot(struct pt_regs *regs) 234 { 235 #ifdef CONFIG_OPENRISC_NO_SPR_SR_DSX 236 /* No delay slot flag, do the old way */ 237 unsigned int op, insn; 238 239 insn = *((unsigned int *)regs->pc); 240 op = insn >> 26; 241 switch (op) { 242 case 0x00: /* l.j */ 243 case 0x01: /* l.jal */ 244 case 0x03: /* l.bnf */ 245 case 0x04: /* l.bf */ 246 case 0x11: /* l.jr */ 247 case 0x12: /* l.jalr */ 248 return 1; 249 default: 250 return 0; 251 } 252 #else 253 return mfspr(SPR_SR) & SPR_SR_DSX; 254 #endif 255 } 256 257 static inline void adjust_pc(struct pt_regs *regs, unsigned long address) 258 { 259 int displacement; 260 unsigned int rb, op, jmp; 261 262 if (unlikely(in_delay_slot(regs))) { 263 /* In delay slot, instruction at pc is a branch, simulate it */ 264 jmp = *((unsigned int *)regs->pc); 265 266 displacement = sign_extend32(((jmp) & 0x3ffffff) << 2, 27); 267 rb = (jmp & 0x0000ffff) >> 11; 268 op = jmp >> 26; 269 270 switch (op) { 271 case 0x00: /* l.j */ 272 regs->pc += displacement; 273 return; 274 case 0x01: /* l.jal */ 275 regs->pc += displacement; 276 regs->gpr[9] = regs->pc + 8; 277 return; 278 case 0x03: /* l.bnf */ 279 if (regs->sr & SPR_SR_F) 280 regs->pc += 8; 281 else 282 regs->pc += displacement; 283 return; 284 case 0x04: /* l.bf */ 285 if (regs->sr & SPR_SR_F) 286 regs->pc += displacement; 287 else 288 regs->pc += 8; 289 return; 290 case 0x11: /* l.jr */ 291 regs->pc = regs->gpr[rb]; 292 return; 293 case 0x12: /* l.jalr */ 294 regs->pc = regs->gpr[rb]; 295 regs->gpr[9] = regs->pc + 8; 296 return; 297 default: 298 break; 299 } 300 } else { 301 regs->pc += 4; 302 } 303 } 304 305 static inline void simulate_lwa(struct pt_regs *regs, unsigned long address, 306 unsigned int insn) 307 { 308 unsigned int ra, rd; 309 unsigned long value; 310 unsigned long orig_pc; 311 long imm; 312 313 const struct exception_table_entry *entry; 314 315 orig_pc = regs->pc; 316 adjust_pc(regs, address); 317 318 ra = (insn >> 16) & 0x1f; 319 rd = (insn >> 21) & 0x1f; 320 imm = (short)insn; 321 lwa_addr = (unsigned long __user *)(regs->gpr[ra] + imm); 322 323 if ((unsigned long)lwa_addr & 0x3) { 324 do_unaligned_access(regs, address); 325 return; 326 } 327 328 if (get_user(value, lwa_addr)) { 329 if (user_mode(regs)) { 330 force_sig(SIGSEGV); 331 return; 332 } 333 334 if ((entry = search_exception_tables(orig_pc))) { 335 regs->pc = entry->fixup; 336 return; 337 } 338 339 /* kernel access in kernel space, load it directly */ 340 value = *((unsigned long *)lwa_addr); 341 } 342 343 lwa_flag = 1; 344 regs->gpr[rd] = value; 345 } 346 347 static inline void simulate_swa(struct pt_regs *regs, unsigned long address, 348 unsigned int insn) 349 { 350 unsigned long __user *vaddr; 351 unsigned long orig_pc; 352 unsigned int ra, rb; 353 long imm; 354 355 const struct exception_table_entry *entry; 356 357 orig_pc = regs->pc; 358 adjust_pc(regs, address); 359 360 ra = (insn >> 16) & 0x1f; 361 rb = (insn >> 11) & 0x1f; 362 imm = (short)(((insn & 0x2200000) >> 10) | (insn & 0x7ff)); 363 vaddr = (unsigned long __user *)(regs->gpr[ra] + imm); 364 365 if (!lwa_flag || vaddr != lwa_addr) { 366 regs->sr &= ~SPR_SR_F; 367 return; 368 } 369 370 if ((unsigned long)vaddr & 0x3) { 371 do_unaligned_access(regs, address); 372 return; 373 } 374 375 if (put_user(regs->gpr[rb], vaddr)) { 376 if (user_mode(regs)) { 377 force_sig(SIGSEGV); 378 return; 379 } 380 381 if ((entry = search_exception_tables(orig_pc))) { 382 regs->pc = entry->fixup; 383 return; 384 } 385 386 /* kernel access in kernel space, store it directly */ 387 *((unsigned long *)vaddr) = regs->gpr[rb]; 388 } 389 390 lwa_flag = 0; 391 regs->sr |= SPR_SR_F; 392 } 393 394 #define INSN_LWA 0x1b 395 #define INSN_SWA 0x33 396 397 asmlinkage void do_illegal_instruction(struct pt_regs *regs, 398 unsigned long address) 399 { 400 unsigned int op; 401 unsigned int insn = *((unsigned int *)address); 402 403 op = insn >> 26; 404 405 switch (op) { 406 case INSN_LWA: 407 simulate_lwa(regs, address, insn); 408 return; 409 410 case INSN_SWA: 411 simulate_swa(regs, address, insn); 412 return; 413 414 default: 415 break; 416 } 417 418 if (user_mode(regs)) { 419 /* Send a SIGILL */ 420 force_sig_fault(SIGILL, ILL_ILLOPC, (void __user *)address); 421 } else { /* Kernel mode */ 422 printk("KERNEL: Illegal instruction (SIGILL) 0x%.8lx\n", 423 address); 424 show_registers(regs); 425 die("Die:", regs, address); 426 } 427 } 428