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

source code of linux/arch/openrisc/kernel/traps.c