xref: /openbmc/linux/arch/openrisc/kernel/traps.c (revision 45051539) 
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/io.h>
34 #include <asm/pgtable.h>
35 #include <asm/unwinder.h>
36 #include <asm/sections.h>
37 
38 int kstack_depth_to_print = 0x180;
39 int lwa_flag;
40 unsigned long __user *lwa_addr;
41 
42 void print_trace(void *data, unsigned long addr, int reliable)
43 {
44 	pr_emerg("[<%p>] %s%pS\n", (void *) addr, reliable ? "" : "? ",
45 	       (void *) addr);
46 }
47 
48 /* displays a short stack trace */
49 void show_stack(struct task_struct *task, unsigned long *esp)
50 {
51 	if (esp == NULL)
52 		esp = (unsigned long *)&esp;
53 
54 	pr_emerg("Call trace:\n");
55 	unwind_stack(NULL, esp, print_trace);
56 }
57 
58 void show_trace_task(struct task_struct *tsk)
59 {
60 	/*
61 	 * TODO: SysRq-T trace dump...
62 	 */
63 }
64 
65 void show_registers(struct pt_regs *regs)
66 {
67 	int i;
68 	int in_kernel = 1;
69 	unsigned long esp;
70 
71 	esp = (unsigned long)(regs->sp);
72 	if (user_mode(regs))
73 		in_kernel = 0;
74 
75 	printk("CPU #: %d\n"
76 	       "   PC: %08lx    SR: %08lx    SP: %08lx\n",
77 	       smp_processor_id(), regs->pc, regs->sr, regs->sp);
78 	printk("GPR00: %08lx GPR01: %08lx GPR02: %08lx GPR03: %08lx\n",
79 	       0L, regs->gpr[1], regs->gpr[2], regs->gpr[3]);
80 	printk("GPR04: %08lx GPR05: %08lx GPR06: %08lx GPR07: %08lx\n",
81 	       regs->gpr[4], regs->gpr[5], regs->gpr[6], regs->gpr[7]);
82 	printk("GPR08: %08lx GPR09: %08lx GPR10: %08lx GPR11: %08lx\n",
83 	       regs->gpr[8], regs->gpr[9], regs->gpr[10], regs->gpr[11]);
84 	printk("GPR12: %08lx GPR13: %08lx GPR14: %08lx GPR15: %08lx\n",
85 	       regs->gpr[12], regs->gpr[13], regs->gpr[14], regs->gpr[15]);
86 	printk("GPR16: %08lx GPR17: %08lx GPR18: %08lx GPR19: %08lx\n",
87 	       regs->gpr[16], regs->gpr[17], regs->gpr[18], regs->gpr[19]);
88 	printk("GPR20: %08lx GPR21: %08lx GPR22: %08lx GPR23: %08lx\n",
89 	       regs->gpr[20], regs->gpr[21], regs->gpr[22], regs->gpr[23]);
90 	printk("GPR24: %08lx GPR25: %08lx GPR26: %08lx GPR27: %08lx\n",
91 	       regs->gpr[24], regs->gpr[25], regs->gpr[26], regs->gpr[27]);
92 	printk("GPR28: %08lx GPR29: %08lx GPR30: %08lx GPR31: %08lx\n",
93 	       regs->gpr[28], regs->gpr[29], regs->gpr[30], regs->gpr[31]);
94 	printk("  RES: %08lx oGPR11: %08lx\n",
95 	       regs->gpr[11], regs->orig_gpr11);
96 
97 	printk("Process %s (pid: %d, stackpage=%08lx)\n",
98 	       current->comm, current->pid, (unsigned long)current);
99 	/*
100 	 * When in-kernel, we also print out the stack and code at the
101 	 * time of the fault..
102 	 */
103 	if (in_kernel) {
104 
105 		printk("\nStack: ");
106 		show_stack(NULL, (unsigned long *)esp);
107 
108 		printk("\nCode: ");
109 		if (regs->pc < PAGE_OFFSET)
110 			goto bad;
111 
112 		for (i = -24; i < 24; i++) {
113 			unsigned char c;
114 			if (__get_user(c, &((unsigned char *)regs->pc)[i])) {
115 bad:
116 				printk(" Bad PC value.");
117 				break;
118 			}
119 
120 			if (i == 0)
121 				printk("(%02x) ", c);
122 			else
123 				printk("%02x ", c);
124 		}
125 	}
126 	printk("\n");
127 }
128 
129 void nommu_dump_state(struct pt_regs *regs,
130 		      unsigned long ea, unsigned long vector)
131 {
132 	int i;
133 	unsigned long addr, stack = regs->sp;
134 
135 	printk("\n\r[nommu_dump_state] :: ea %lx, vector %lx\n\r", ea, vector);
136 
137 	printk("CPU #: %d\n"
138 	       "   PC: %08lx    SR: %08lx    SP: %08lx\n",
139 	       0, regs->pc, regs->sr, regs->sp);
140 	printk("GPR00: %08lx GPR01: %08lx GPR02: %08lx GPR03: %08lx\n",
141 	       0L, regs->gpr[1], regs->gpr[2], regs->gpr[3]);
142 	printk("GPR04: %08lx GPR05: %08lx GPR06: %08lx GPR07: %08lx\n",
143 	       regs->gpr[4], regs->gpr[5], regs->gpr[6], regs->gpr[7]);
144 	printk("GPR08: %08lx GPR09: %08lx GPR10: %08lx GPR11: %08lx\n",
145 	       regs->gpr[8], regs->gpr[9], regs->gpr[10], regs->gpr[11]);
146 	printk("GPR12: %08lx GPR13: %08lx GPR14: %08lx GPR15: %08lx\n",
147 	       regs->gpr[12], regs->gpr[13], regs->gpr[14], regs->gpr[15]);
148 	printk("GPR16: %08lx GPR17: %08lx GPR18: %08lx GPR19: %08lx\n",
149 	       regs->gpr[16], regs->gpr[17], regs->gpr[18], regs->gpr[19]);
150 	printk("GPR20: %08lx GPR21: %08lx GPR22: %08lx GPR23: %08lx\n",
151 	       regs->gpr[20], regs->gpr[21], regs->gpr[22], regs->gpr[23]);
152 	printk("GPR24: %08lx GPR25: %08lx GPR26: %08lx GPR27: %08lx\n",
153 	       regs->gpr[24], regs->gpr[25], regs->gpr[26], regs->gpr[27]);
154 	printk("GPR28: %08lx GPR29: %08lx GPR30: %08lx GPR31: %08lx\n",
155 	       regs->gpr[28], regs->gpr[29], regs->gpr[30], regs->gpr[31]);
156 	printk("  RES: %08lx oGPR11: %08lx\n",
157 	       regs->gpr[11], regs->orig_gpr11);
158 
159 	printk("Process %s (pid: %d, stackpage=%08lx)\n",
160 	       ((struct task_struct *)(__pa(current)))->comm,
161 	       ((struct task_struct *)(__pa(current)))->pid,
162 	       (unsigned long)current);
163 
164 	printk("\nStack: ");
165 	printk("Stack dump [0x%08lx]:\n", (unsigned long)stack);
166 	for (i = 0; i < kstack_depth_to_print; i++) {
167 		if (((long)stack & (THREAD_SIZE - 1)) == 0)
168 			break;
169 		stack++;
170 
171 		printk("%lx :: sp + %02d: 0x%08lx\n", stack, i * 4,
172 		       *((unsigned long *)(__pa(stack))));
173 	}
174 	printk("\n");
175 
176 	printk("Call Trace:   ");
177 	i = 1;
178 	while (((long)stack & (THREAD_SIZE - 1)) != 0) {
179 		addr = *((unsigned long *)__pa(stack));
180 		stack++;
181 
182 		if (kernel_text_address(addr)) {
183 			if (i && ((i % 6) == 0))
184 				printk("\n ");
185 			printk(" [<%08lx>]", addr);
186 			i++;
187 		}
188 	}
189 	printk("\n");
190 
191 	printk("\nCode: ");
192 
193 	for (i = -24; i < 24; i++) {
194 		unsigned char c;
195 		c = ((unsigned char *)(__pa(regs->pc)))[i];
196 
197 		if (i == 0)
198 			printk("(%02x) ", c);
199 		else
200 			printk("%02x ", c);
201 	}
202 	printk("\n");
203 }
204 
205 /* This is normally the 'Oops' routine */
206 void die(const char *str, struct pt_regs *regs, long err)
207 {
208 
209 	console_verbose();
210 	printk("\n%s#: %04lx\n", str, err & 0xffff);
211 	show_registers(regs);
212 #ifdef CONFIG_JUMP_UPON_UNHANDLED_EXCEPTION
213 	printk("\n\nUNHANDLED_EXCEPTION: entering infinite loop\n");
214 
215 	/* shut down interrupts */
216 	local_irq_disable();
217 
218 	__asm__ __volatile__("l.nop   1");
219 	do {} while (1);
220 #endif
221 	do_exit(SIGSEGV);
222 }
223 
224 /* This is normally the 'Oops' routine */
225 void die_if_kernel(const char *str, struct pt_regs *regs, long err)
226 {
227 	if (user_mode(regs))
228 		return;
229 
230 	die(str, regs, err);
231 }
232 
233 void unhandled_exception(struct pt_regs *regs, int ea, int vector)
234 {
235 	printk("Unable to handle exception at EA =0x%x, vector 0x%x",
236 	       ea, vector);
237 	die("Oops", regs, 9);
238 }
239 
240 void __init trap_init(void)
241 {
242 	/* Nothing needs to be done */
243 }
244 
245 asmlinkage void do_trap(struct pt_regs *regs, unsigned long address)
246 {
247 	force_sig_fault(SIGTRAP, TRAP_TRACE, (void __user *)address, current);
248 
249 	regs->pc += 4;
250 }
251 
252 asmlinkage void do_unaligned_access(struct pt_regs *regs, unsigned long address)
253 {
254 	if (user_mode(regs)) {
255 		/* Send a SIGBUS */
256 		force_sig_fault(SIGBUS, BUS_ADRALN, (void __user *)address, current);
257 	} else {
258 		printk("KERNEL: Unaligned Access 0x%.8lx\n", address);
259 		show_registers(regs);
260 		die("Die:", regs, address);
261 	}
262 
263 }
264 
265 asmlinkage void do_bus_fault(struct pt_regs *regs, unsigned long address)
266 {
267 	if (user_mode(regs)) {
268 		/* Send a SIGBUS */
269 		force_sig_fault(SIGBUS, BUS_ADRERR, (void __user *)address, current);
270 	} else {		/* Kernel mode */
271 		printk("KERNEL: Bus error (SIGBUS) 0x%.8lx\n", address);
272 		show_registers(regs);
273 		die("Die:", regs, address);
274 	}
275 }
276 
277 static inline int in_delay_slot(struct pt_regs *regs)
278 {
279 #ifdef CONFIG_OPENRISC_NO_SPR_SR_DSX
280 	/* No delay slot flag, do the old way */
281 	unsigned int op, insn;
282 
283 	insn = *((unsigned int *)regs->pc);
284 	op = insn >> 26;
285 	switch (op) {
286 	case 0x00: /* l.j */
287 	case 0x01: /* l.jal */
288 	case 0x03: /* l.bnf */
289 	case 0x04: /* l.bf */
290 	case 0x11: /* l.jr */
291 	case 0x12: /* l.jalr */
292 		return 1;
293 	default:
294 		return 0;
295 	}
296 #else
297 	return mfspr(SPR_SR) & SPR_SR_DSX;
298 #endif
299 }
300 
301 static inline void adjust_pc(struct pt_regs *regs, unsigned long address)
302 {
303 	int displacement;
304 	unsigned int rb, op, jmp;
305 
306 	if (unlikely(in_delay_slot(regs))) {
307 		/* In delay slot, instruction at pc is a branch, simulate it */
308 		jmp = *((unsigned int *)regs->pc);
309 
310 		displacement = sign_extend32(((jmp) & 0x3ffffff) << 2, 27);
311 		rb = (jmp & 0x0000ffff) >> 11;
312 		op = jmp >> 26;
313 
314 		switch (op) {
315 		case 0x00: /* l.j */
316 			regs->pc += displacement;
317 			return;
318 		case 0x01: /* l.jal */
319 			regs->pc += displacement;
320 			regs->gpr[9] = regs->pc + 8;
321 			return;
322 		case 0x03: /* l.bnf */
323 			if (regs->sr & SPR_SR_F)
324 				regs->pc += 8;
325 			else
326 				regs->pc += displacement;
327 			return;
328 		case 0x04: /* l.bf */
329 			if (regs->sr & SPR_SR_F)
330 				regs->pc += displacement;
331 			else
332 				regs->pc += 8;
333 			return;
334 		case 0x11: /* l.jr */
335 			regs->pc = regs->gpr[rb];
336 			return;
337 		case 0x12: /* l.jalr */
338 			regs->pc = regs->gpr[rb];
339 			regs->gpr[9] = regs->pc + 8;
340 			return;
341 		default:
342 			break;
343 		}
344 	} else {
345 		regs->pc += 4;
346 	}
347 }
348 
349 static inline void simulate_lwa(struct pt_regs *regs, unsigned long address,
350 				unsigned int insn)
351 {
352 	unsigned int ra, rd;
353 	unsigned long value;
354 	unsigned long orig_pc;
355 	long imm;
356 
357 	const struct exception_table_entry *entry;
358 
359 	orig_pc = regs->pc;
360 	adjust_pc(regs, address);
361 
362 	ra = (insn >> 16) & 0x1f;
363 	rd = (insn >> 21) & 0x1f;
364 	imm = (short)insn;
365 	lwa_addr = (unsigned long __user *)(regs->gpr[ra] + imm);
366 
367 	if ((unsigned long)lwa_addr & 0x3) {
368 		do_unaligned_access(regs, address);
369 		return;
370 	}
371 
372 	if (get_user(value, lwa_addr)) {
373 		if (user_mode(regs)) {
374 			force_sig(SIGSEGV, current);
375 			return;
376 		}
377 
378 		if ((entry = search_exception_tables(orig_pc))) {
379 			regs->pc = entry->fixup;
380 			return;
381 		}
382 
383 		/* kernel access in kernel space, load it directly */
384 		value = *((unsigned long *)lwa_addr);
385 	}
386 
387 	lwa_flag = 1;
388 	regs->gpr[rd] = value;
389 }
390 
391 static inline void simulate_swa(struct pt_regs *regs, unsigned long address,
392 				unsigned int insn)
393 {
394 	unsigned long __user *vaddr;
395 	unsigned long orig_pc;
396 	unsigned int ra, rb;
397 	long imm;
398 
399 	const struct exception_table_entry *entry;
400 
401 	orig_pc = regs->pc;
402 	adjust_pc(regs, address);
403 
404 	ra = (insn >> 16) & 0x1f;
405 	rb = (insn >> 11) & 0x1f;
406 	imm = (short)(((insn & 0x2200000) >> 10) | (insn & 0x7ff));
407 	vaddr = (unsigned long __user *)(regs->gpr[ra] + imm);
408 
409 	if (!lwa_flag || vaddr != lwa_addr) {
410 		regs->sr &= ~SPR_SR_F;
411 		return;
412 	}
413 
414 	if ((unsigned long)vaddr & 0x3) {
415 		do_unaligned_access(regs, address);
416 		return;
417 	}
418 
419 	if (put_user(regs->gpr[rb], vaddr)) {
420 		if (user_mode(regs)) {
421 			force_sig(SIGSEGV, current);
422 			return;
423 		}
424 
425 		if ((entry = search_exception_tables(orig_pc))) {
426 			regs->pc = entry->fixup;
427 			return;
428 		}
429 
430 		/* kernel access in kernel space, store it directly */
431 		*((unsigned long *)vaddr) = regs->gpr[rb];
432 	}
433 
434 	lwa_flag = 0;
435 	regs->sr |= SPR_SR_F;
436 }
437 
438 #define INSN_LWA	0x1b
439 #define INSN_SWA	0x33
440 
441 asmlinkage void do_illegal_instruction(struct pt_regs *regs,
442 				       unsigned long address)
443 {
444 	unsigned int op;
445 	unsigned int insn = *((unsigned int *)address);
446 
447 	op = insn >> 26;
448 
449 	switch (op) {
450 	case INSN_LWA:
451 		simulate_lwa(regs, address, insn);
452 		return;
453 
454 	case INSN_SWA:
455 		simulate_swa(regs, address, insn);
456 		return;
457 
458 	default:
459 		break;
460 	}
461 
462 	if (user_mode(regs)) {
463 		/* Send a SIGILL */
464 		force_sig_fault(SIGILL, ILL_ILLOPC, (void __user *)address, current);
465 	} else {		/* Kernel mode */
466 		printk("KERNEL: Illegal instruction (SIGILL) 0x%.8lx\n",
467 		       address);
468 		show_registers(regs);
469 		die("Die:", regs, address);
470 	}
471 }
472