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