xref: /linux/arch/openrisc/kernel/traps.c (revision bfd5bb6f90af092aa345b15cd78143956a13c2a8) 
1 /*
2  * OpenRISC traps.c
3  *
4  * Linux architectural port borrowing liberally from similar works of
5  * others.  All original copyrights apply as per the original source
6  * declaration.
7  *
8  * Modifications for the OpenRISC architecture:
9  * Copyright (C) 2003 Matjaz Breskvar <phoenix@bsemi.com>
10  * Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se>
11  *
12  *      This program is free software; you can redistribute it and/or
13  *      modify it under the terms of the GNU General Public License
14  *      as published by the Free Software Foundation; either version
15  *      2 of the License, or (at your option) any later version.
16  *
17  *  Here we handle the break vectors not used by the system call
18  *  mechanism, as well as some general stack/register dumping
19  *  things.
20  *
21  */
22 
23 #include <linux/init.h>
24 #include <linux/sched.h>
25 #include <linux/sched/debug.h>
26 #include <linux/sched/task_stack.h>
27 #include <linux/kernel.h>
28 #include <linux/extable.h>
29 #include <linux/kmod.h>
30 #include <linux/string.h>
31 #include <linux/errno.h>
32 #include <linux/ptrace.h>
33 #include <linux/timer.h>
34 #include <linux/mm.h>
35 #include <linux/kallsyms.h>
36 #include <linux/uaccess.h>
37 
38 #include <asm/segment.h>
39 #include <asm/io.h>
40 #include <asm/pgtable.h>
41 #include <asm/unwinder.h>
42 #include <asm/sections.h>
43 
44 int kstack_depth_to_print = 0x180;
45 int lwa_flag;
46 unsigned long __user *lwa_addr;
47 
48 void print_trace(void *data, unsigned long addr, int reliable)
49 {
50 	pr_emerg("[<%p>] %s%pS\n", (void *) addr, reliable ? "" : "? ",
51 	       (void *) addr);
52 }
53 
54 /* displays a short stack trace */
55 void show_stack(struct task_struct *task, unsigned long *esp)
56 {
57 	if (esp == NULL)
58 		esp = (unsigned long *)&esp;
59 
60 	pr_emerg("Call trace:\n");
61 	unwind_stack(NULL, esp, print_trace);
62 }
63 
64 void show_trace_task(struct task_struct *tsk)
65 {
66 	/*
67 	 * TODO: SysRq-T trace dump...
68 	 */
69 }
70 
71 void show_registers(struct pt_regs *regs)
72 {
73 	int i;
74 	int in_kernel = 1;
75 	unsigned long esp;
76 
77 	esp = (unsigned long)(regs->sp);
78 	if (user_mode(regs))
79 		in_kernel = 0;
80 
81 	printk("CPU #: %d\n"
82 	       "   PC: %08lx    SR: %08lx    SP: %08lx\n",
83 	       smp_processor_id(), regs->pc, regs->sr, regs->sp);
84 	printk("GPR00: %08lx GPR01: %08lx GPR02: %08lx GPR03: %08lx\n",
85 	       0L, regs->gpr[1], regs->gpr[2], regs->gpr[3]);
86 	printk("GPR04: %08lx GPR05: %08lx GPR06: %08lx GPR07: %08lx\n",
87 	       regs->gpr[4], regs->gpr[5], regs->gpr[6], regs->gpr[7]);
88 	printk("GPR08: %08lx GPR09: %08lx GPR10: %08lx GPR11: %08lx\n",
89 	       regs->gpr[8], regs->gpr[9], regs->gpr[10], regs->gpr[11]);
90 	printk("GPR12: %08lx GPR13: %08lx GPR14: %08lx GPR15: %08lx\n",
91 	       regs->gpr[12], regs->gpr[13], regs->gpr[14], regs->gpr[15]);
92 	printk("GPR16: %08lx GPR17: %08lx GPR18: %08lx GPR19: %08lx\n",
93 	       regs->gpr[16], regs->gpr[17], regs->gpr[18], regs->gpr[19]);
94 	printk("GPR20: %08lx GPR21: %08lx GPR22: %08lx GPR23: %08lx\n",
95 	       regs->gpr[20], regs->gpr[21], regs->gpr[22], regs->gpr[23]);
96 	printk("GPR24: %08lx GPR25: %08lx GPR26: %08lx GPR27: %08lx\n",
97 	       regs->gpr[24], regs->gpr[25], regs->gpr[26], regs->gpr[27]);
98 	printk("GPR28: %08lx GPR29: %08lx GPR30: %08lx GPR31: %08lx\n",
99 	       regs->gpr[28], regs->gpr[29], regs->gpr[30], regs->gpr[31]);
100 	printk("  RES: %08lx oGPR11: %08lx\n",
101 	       regs->gpr[11], regs->orig_gpr11);
102 
103 	printk("Process %s (pid: %d, stackpage=%08lx)\n",
104 	       current->comm, current->pid, (unsigned long)current);
105 	/*
106 	 * When in-kernel, we also print out the stack and code at the
107 	 * time of the fault..
108 	 */
109 	if (in_kernel) {
110 
111 		printk("\nStack: ");
112 		show_stack(NULL, (unsigned long *)esp);
113 
114 		printk("\nCode: ");
115 		if (regs->pc < PAGE_OFFSET)
116 			goto bad;
117 
118 		for (i = -24; i < 24; i++) {
119 			unsigned char c;
120 			if (__get_user(c, &((unsigned char *)regs->pc)[i])) {
121 bad:
122 				printk(" Bad PC value.");
123 				break;
124 			}
125 
126 			if (i == 0)
127 				printk("(%02x) ", c);
128 			else
129 				printk("%02x ", c);
130 		}
131 	}
132 	printk("\n");
133 }
134 
135 void nommu_dump_state(struct pt_regs *regs,
136 		      unsigned long ea, unsigned long vector)
137 {
138 	int i;
139 	unsigned long addr, stack = regs->sp;
140 
141 	printk("\n\r[nommu_dump_state] :: ea %lx, vector %lx\n\r", ea, vector);
142 
143 	printk("CPU #: %d\n"
144 	       "   PC: %08lx    SR: %08lx    SP: %08lx\n",
145 	       0, regs->pc, regs->sr, regs->sp);
146 	printk("GPR00: %08lx GPR01: %08lx GPR02: %08lx GPR03: %08lx\n",
147 	       0L, regs->gpr[1], regs->gpr[2], regs->gpr[3]);
148 	printk("GPR04: %08lx GPR05: %08lx GPR06: %08lx GPR07: %08lx\n",
149 	       regs->gpr[4], regs->gpr[5], regs->gpr[6], regs->gpr[7]);
150 	printk("GPR08: %08lx GPR09: %08lx GPR10: %08lx GPR11: %08lx\n",
151 	       regs->gpr[8], regs->gpr[9], regs->gpr[10], regs->gpr[11]);
152 	printk("GPR12: %08lx GPR13: %08lx GPR14: %08lx GPR15: %08lx\n",
153 	       regs->gpr[12], regs->gpr[13], regs->gpr[14], regs->gpr[15]);
154 	printk("GPR16: %08lx GPR17: %08lx GPR18: %08lx GPR19: %08lx\n",
155 	       regs->gpr[16], regs->gpr[17], regs->gpr[18], regs->gpr[19]);
156 	printk("GPR20: %08lx GPR21: %08lx GPR22: %08lx GPR23: %08lx\n",
157 	       regs->gpr[20], regs->gpr[21], regs->gpr[22], regs->gpr[23]);
158 	printk("GPR24: %08lx GPR25: %08lx GPR26: %08lx GPR27: %08lx\n",
159 	       regs->gpr[24], regs->gpr[25], regs->gpr[26], regs->gpr[27]);
160 	printk("GPR28: %08lx GPR29: %08lx GPR30: %08lx GPR31: %08lx\n",
161 	       regs->gpr[28], regs->gpr[29], regs->gpr[30], regs->gpr[31]);
162 	printk("  RES: %08lx oGPR11: %08lx\n",
163 	       regs->gpr[11], regs->orig_gpr11);
164 
165 	printk("Process %s (pid: %d, stackpage=%08lx)\n",
166 	       ((struct task_struct *)(__pa(current)))->comm,
167 	       ((struct task_struct *)(__pa(current)))->pid,
168 	       (unsigned long)current);
169 
170 	printk("\nStack: ");
171 	printk("Stack dump [0x%08lx]:\n", (unsigned long)stack);
172 	for (i = 0; i < kstack_depth_to_print; i++) {
173 		if (((long)stack & (THREAD_SIZE - 1)) == 0)
174 			break;
175 		stack++;
176 
177 		printk("%lx :: sp + %02d: 0x%08lx\n", stack, i * 4,
178 		       *((unsigned long *)(__pa(stack))));
179 	}
180 	printk("\n");
181 
182 	printk("Call Trace:   ");
183 	i = 1;
184 	while (((long)stack & (THREAD_SIZE - 1)) != 0) {
185 		addr = *((unsigned long *)__pa(stack));
186 		stack++;
187 
188 		if (kernel_text_address(addr)) {
189 			if (i && ((i % 6) == 0))
190 				printk("\n ");
191 			printk(" [<%08lx>]", addr);
192 			i++;
193 		}
194 	}
195 	printk("\n");
196 
197 	printk("\nCode: ");
198 
199 	for (i = -24; i < 24; i++) {
200 		unsigned char c;
201 		c = ((unsigned char *)(__pa(regs->pc)))[i];
202 
203 		if (i == 0)
204 			printk("(%02x) ", c);
205 		else
206 			printk("%02x ", c);
207 	}
208 	printk("\n");
209 }
210 
211 /* This is normally the 'Oops' routine */
212 void die(const char *str, struct pt_regs *regs, long err)
213 {
214 
215 	console_verbose();
216 	printk("\n%s#: %04lx\n", str, err & 0xffff);
217 	show_registers(regs);
218 #ifdef CONFIG_JUMP_UPON_UNHANDLED_EXCEPTION
219 	printk("\n\nUNHANDLED_EXCEPTION: entering infinite loop\n");
220 
221 	/* shut down interrupts */
222 	local_irq_disable();
223 
224 	__asm__ __volatile__("l.nop   1");
225 	do {} while (1);
226 #endif
227 	do_exit(SIGSEGV);
228 }
229 
230 /* This is normally the 'Oops' routine */
231 void die_if_kernel(const char *str, struct pt_regs *regs, long err)
232 {
233 	if (user_mode(regs))
234 		return;
235 
236 	die(str, regs, err);
237 }
238 
239 void unhandled_exception(struct pt_regs *regs, int ea, int vector)
240 {
241 	printk("Unable to handle exception at EA =0x%x, vector 0x%x",
242 	       ea, vector);
243 	die("Oops", regs, 9);
244 }
245 
246 void __init trap_init(void)
247 {
248 	/* Nothing needs to be done */
249 }
250 
251 asmlinkage void do_trap(struct pt_regs *regs, unsigned long address)
252 {
253 	force_sig_fault(SIGTRAP, TRAP_TRACE, (void __user *)address, current);
254 
255 	regs->pc += 4;
256 }
257 
258 asmlinkage void do_unaligned_access(struct pt_regs *regs, unsigned long address)
259 {
260 	if (user_mode(regs)) {
261 		/* Send a SIGBUS */
262 		force_sig_fault(SIGBUS, BUS_ADRALN, (void __user *)address, current);
263 	} else {
264 		printk("KERNEL: Unaligned Access 0x%.8lx\n", address);
265 		show_registers(regs);
266 		die("Die:", regs, address);
267 	}
268 
269 }
270 
271 asmlinkage void do_bus_fault(struct pt_regs *regs, unsigned long address)
272 {
273 	if (user_mode(regs)) {
274 		/* Send a SIGBUS */
275 		force_sig_fault(SIGBUS, BUS_ADRERR, (void __user *)address, current);
276 	} else {		/* Kernel mode */
277 		printk("KERNEL: Bus error (SIGBUS) 0x%.8lx\n", address);
278 		show_registers(regs);
279 		die("Die:", regs, address);
280 	}
281 }
282 
283 static inline int in_delay_slot(struct pt_regs *regs)
284 {
285 #ifdef CONFIG_OPENRISC_NO_SPR_SR_DSX
286 	/* No delay slot flag, do the old way */
287 	unsigned int op, insn;
288 
289 	insn = *((unsigned int *)regs->pc);
290 	op = insn >> 26;
291 	switch (op) {
292 	case 0x00: /* l.j */
293 	case 0x01: /* l.jal */
294 	case 0x03: /* l.bnf */
295 	case 0x04: /* l.bf */
296 	case 0x11: /* l.jr */
297 	case 0x12: /* l.jalr */
298 		return 1;
299 	default:
300 		return 0;
301 	}
302 #else
303 	return mfspr(SPR_SR) & SPR_SR_DSX;
304 #endif
305 }
306 
307 static inline void adjust_pc(struct pt_regs *regs, unsigned long address)
308 {
309 	int displacement;
310 	unsigned int rb, op, jmp;
311 
312 	if (unlikely(in_delay_slot(regs))) {
313 		/* In delay slot, instruction at pc is a branch, simulate it */
314 		jmp = *((unsigned int *)regs->pc);
315 
316 		displacement = sign_extend32(((jmp) & 0x3ffffff) << 2, 27);
317 		rb = (jmp & 0x0000ffff) >> 11;
318 		op = jmp >> 26;
319 
320 		switch (op) {
321 		case 0x00: /* l.j */
322 			regs->pc += displacement;
323 			return;
324 		case 0x01: /* l.jal */
325 			regs->pc += displacement;
326 			regs->gpr[9] = regs->pc + 8;
327 			return;
328 		case 0x03: /* l.bnf */
329 			if (regs->sr & SPR_SR_F)
330 				regs->pc += 8;
331 			else
332 				regs->pc += displacement;
333 			return;
334 		case 0x04: /* l.bf */
335 			if (regs->sr & SPR_SR_F)
336 				regs->pc += displacement;
337 			else
338 				regs->pc += 8;
339 			return;
340 		case 0x11: /* l.jr */
341 			regs->pc = regs->gpr[rb];
342 			return;
343 		case 0x12: /* l.jalr */
344 			regs->pc = regs->gpr[rb];
345 			regs->gpr[9] = regs->pc + 8;
346 			return;
347 		default:
348 			break;
349 		}
350 	} else {
351 		regs->pc += 4;
352 	}
353 }
354 
355 static inline void simulate_lwa(struct pt_regs *regs, unsigned long address,
356 				unsigned int insn)
357 {
358 	unsigned int ra, rd;
359 	unsigned long value;
360 	unsigned long orig_pc;
361 	long imm;
362 
363 	const struct exception_table_entry *entry;
364 
365 	orig_pc = regs->pc;
366 	adjust_pc(regs, address);
367 
368 	ra = (insn >> 16) & 0x1f;
369 	rd = (insn >> 21) & 0x1f;
370 	imm = (short)insn;
371 	lwa_addr = (unsigned long __user *)(regs->gpr[ra] + imm);
372 
373 	if ((unsigned long)lwa_addr & 0x3) {
374 		do_unaligned_access(regs, address);
375 		return;
376 	}
377 
378 	if (get_user(value, lwa_addr)) {
379 		if (user_mode(regs)) {
380 			force_sig(SIGSEGV, current);
381 			return;
382 		}
383 
384 		if ((entry = search_exception_tables(orig_pc))) {
385 			regs->pc = entry->fixup;
386 			return;
387 		}
388 
389 		/* kernel access in kernel space, load it directly */
390 		value = *((unsigned long *)lwa_addr);
391 	}
392 
393 	lwa_flag = 1;
394 	regs->gpr[rd] = value;
395 }
396 
397 static inline void simulate_swa(struct pt_regs *regs, unsigned long address,
398 				unsigned int insn)
399 {
400 	unsigned long __user *vaddr;
401 	unsigned long orig_pc;
402 	unsigned int ra, rb;
403 	long imm;
404 
405 	const struct exception_table_entry *entry;
406 
407 	orig_pc = regs->pc;
408 	adjust_pc(regs, address);
409 
410 	ra = (insn >> 16) & 0x1f;
411 	rb = (insn >> 11) & 0x1f;
412 	imm = (short)(((insn & 0x2200000) >> 10) | (insn & 0x7ff));
413 	vaddr = (unsigned long __user *)(regs->gpr[ra] + imm);
414 
415 	if (!lwa_flag || vaddr != lwa_addr) {
416 		regs->sr &= ~SPR_SR_F;
417 		return;
418 	}
419 
420 	if ((unsigned long)vaddr & 0x3) {
421 		do_unaligned_access(regs, address);
422 		return;
423 	}
424 
425 	if (put_user(regs->gpr[rb], vaddr)) {
426 		if (user_mode(regs)) {
427 			force_sig(SIGSEGV, current);
428 			return;
429 		}
430 
431 		if ((entry = search_exception_tables(orig_pc))) {
432 			regs->pc = entry->fixup;
433 			return;
434 		}
435 
436 		/* kernel access in kernel space, store it directly */
437 		*((unsigned long *)vaddr) = regs->gpr[rb];
438 	}
439 
440 	lwa_flag = 0;
441 	regs->sr |= SPR_SR_F;
442 }
443 
444 #define INSN_LWA	0x1b
445 #define INSN_SWA	0x33
446 
447 asmlinkage void do_illegal_instruction(struct pt_regs *regs,
448 				       unsigned long address)
449 {
450 	unsigned int op;
451 	unsigned int insn = *((unsigned int *)address);
452 
453 	op = insn >> 26;
454 
455 	switch (op) {
456 	case INSN_LWA:
457 		simulate_lwa(regs, address, insn);
458 		return;
459 
460 	case INSN_SWA:
461 		simulate_swa(regs, address, insn);
462 		return;
463 
464 	default:
465 		break;
466 	}
467 
468 	if (user_mode(regs)) {
469 		/* Send a SIGILL */
470 		force_sig_fault(SIGILL, ILL_ILLOPC, (void __user *)address, current);
471 	} else {		/* Kernel mode */
472 		printk("KERNEL: Illegal instruction (SIGILL) 0x%.8lx\n",
473 		       address);
474 		show_registers(regs);
475 		die("Die:", regs, address);
476 	}
477 }
478