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
print_trace(void * data,unsigned long addr,int reliable)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
print_data(unsigned long base_addr,unsigned long word,int i)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 */
show_stack(struct task_struct * task,unsigned long * esp,const char * loglvl)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
show_registers(struct pt_regs * regs)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 */
die(const char * str,struct pt_regs * regs,long err)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
unhandled_exception(struct pt_regs * regs,int ea,int vector)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
do_fpe_trap(struct pt_regs * regs,unsigned long address)181 asmlinkage void do_fpe_trap(struct pt_regs *regs, unsigned long address)
182 {
183 if (user_mode(regs)) {
184 int code = FPE_FLTUNK;
185 unsigned long fpcsr = regs->fpcsr;
186
187 if (fpcsr & SPR_FPCSR_IVF)
188 code = FPE_FLTINV;
189 else if (fpcsr & SPR_FPCSR_OVF)
190 code = FPE_FLTOVF;
191 else if (fpcsr & SPR_FPCSR_UNF)
192 code = FPE_FLTUND;
193 else if (fpcsr & SPR_FPCSR_DZF)
194 code = FPE_FLTDIV;
195 else if (fpcsr & SPR_FPCSR_IXF)
196 code = FPE_FLTRES;
197
198 /* Clear all flags */
199 regs->fpcsr &= ~SPR_FPCSR_ALLF;
200
201 force_sig_fault(SIGFPE, code, (void __user *)regs->pc);
202 } else {
203 pr_emerg("KERNEL: Illegal fpe exception 0x%.8lx\n", regs->pc);
204 die("Die:", regs, SIGFPE);
205 }
206 }
207
do_trap(struct pt_regs * regs,unsigned long address)208 asmlinkage void do_trap(struct pt_regs *regs, unsigned long address)
209 {
210 if (user_mode(regs)) {
211 force_sig_fault(SIGTRAP, TRAP_BRKPT, (void __user *)regs->pc);
212 } else {
213 pr_emerg("KERNEL: Illegal trap exception 0x%.8lx\n", regs->pc);
214 die("Die:", regs, SIGILL);
215 }
216 }
217
do_unaligned_access(struct pt_regs * regs,unsigned long address)218 asmlinkage void do_unaligned_access(struct pt_regs *regs, unsigned long address)
219 {
220 if (user_mode(regs)) {
221 /* Send a SIGBUS */
222 force_sig_fault(SIGBUS, BUS_ADRALN, (void __user *)address);
223 } else {
224 printk("KERNEL: Unaligned Access 0x%.8lx\n", address);
225 show_registers(regs);
226 die("Die:", regs, address);
227 }
228
229 }
230
do_bus_fault(struct pt_regs * regs,unsigned long address)231 asmlinkage void do_bus_fault(struct pt_regs *regs, unsigned long address)
232 {
233 if (user_mode(regs)) {
234 /* Send a SIGBUS */
235 force_sig_fault(SIGBUS, BUS_ADRERR, (void __user *)address);
236 } else { /* Kernel mode */
237 printk("KERNEL: Bus error (SIGBUS) 0x%.8lx\n", address);
238 show_registers(regs);
239 die("Die:", regs, address);
240 }
241 }
242
in_delay_slot(struct pt_regs * regs)243 static inline int in_delay_slot(struct pt_regs *regs)
244 {
245 #ifdef CONFIG_OPENRISC_NO_SPR_SR_DSX
246 /* No delay slot flag, do the old way */
247 unsigned int op, insn;
248
249 insn = *((unsigned int *)regs->pc);
250 op = insn >> 26;
251 switch (op) {
252 case 0x00: /* l.j */
253 case 0x01: /* l.jal */
254 case 0x03: /* l.bnf */
255 case 0x04: /* l.bf */
256 case 0x11: /* l.jr */
257 case 0x12: /* l.jalr */
258 return 1;
259 default:
260 return 0;
261 }
262 #else
263 return mfspr(SPR_SR) & SPR_SR_DSX;
264 #endif
265 }
266
adjust_pc(struct pt_regs * regs,unsigned long address)267 static inline void adjust_pc(struct pt_regs *regs, unsigned long address)
268 {
269 int displacement;
270 unsigned int rb, op, jmp;
271
272 if (unlikely(in_delay_slot(regs))) {
273 /* In delay slot, instruction at pc is a branch, simulate it */
274 jmp = *((unsigned int *)regs->pc);
275
276 displacement = sign_extend32(((jmp) & 0x3ffffff) << 2, 27);
277 rb = (jmp & 0x0000ffff) >> 11;
278 op = jmp >> 26;
279
280 switch (op) {
281 case 0x00: /* l.j */
282 regs->pc += displacement;
283 return;
284 case 0x01: /* l.jal */
285 regs->pc += displacement;
286 regs->gpr[9] = regs->pc + 8;
287 return;
288 case 0x03: /* l.bnf */
289 if (regs->sr & SPR_SR_F)
290 regs->pc += 8;
291 else
292 regs->pc += displacement;
293 return;
294 case 0x04: /* l.bf */
295 if (regs->sr & SPR_SR_F)
296 regs->pc += displacement;
297 else
298 regs->pc += 8;
299 return;
300 case 0x11: /* l.jr */
301 regs->pc = regs->gpr[rb];
302 return;
303 case 0x12: /* l.jalr */
304 regs->pc = regs->gpr[rb];
305 regs->gpr[9] = regs->pc + 8;
306 return;
307 default:
308 break;
309 }
310 } else {
311 regs->pc += 4;
312 }
313 }
314
simulate_lwa(struct pt_regs * regs,unsigned long address,unsigned int insn)315 static inline void simulate_lwa(struct pt_regs *regs, unsigned long address,
316 unsigned int insn)
317 {
318 unsigned int ra, rd;
319 unsigned long value;
320 unsigned long orig_pc;
321 long imm;
322
323 const struct exception_table_entry *entry;
324
325 orig_pc = regs->pc;
326 adjust_pc(regs, address);
327
328 ra = (insn >> 16) & 0x1f;
329 rd = (insn >> 21) & 0x1f;
330 imm = (short)insn;
331 lwa_addr = (unsigned long __user *)(regs->gpr[ra] + imm);
332
333 if ((unsigned long)lwa_addr & 0x3) {
334 do_unaligned_access(regs, address);
335 return;
336 }
337
338 if (get_user(value, lwa_addr)) {
339 if (user_mode(regs)) {
340 force_sig(SIGSEGV);
341 return;
342 }
343
344 if ((entry = search_exception_tables(orig_pc))) {
345 regs->pc = entry->fixup;
346 return;
347 }
348
349 /* kernel access in kernel space, load it directly */
350 value = *((unsigned long *)lwa_addr);
351 }
352
353 lwa_flag = 1;
354 regs->gpr[rd] = value;
355 }
356
simulate_swa(struct pt_regs * regs,unsigned long address,unsigned int insn)357 static inline void simulate_swa(struct pt_regs *regs, unsigned long address,
358 unsigned int insn)
359 {
360 unsigned long __user *vaddr;
361 unsigned long orig_pc;
362 unsigned int ra, rb;
363 long imm;
364
365 const struct exception_table_entry *entry;
366
367 orig_pc = regs->pc;
368 adjust_pc(regs, address);
369
370 ra = (insn >> 16) & 0x1f;
371 rb = (insn >> 11) & 0x1f;
372 imm = (short)(((insn & 0x2200000) >> 10) | (insn & 0x7ff));
373 vaddr = (unsigned long __user *)(regs->gpr[ra] + imm);
374
375 if (!lwa_flag || vaddr != lwa_addr) {
376 regs->sr &= ~SPR_SR_F;
377 return;
378 }
379
380 if ((unsigned long)vaddr & 0x3) {
381 do_unaligned_access(regs, address);
382 return;
383 }
384
385 if (put_user(regs->gpr[rb], vaddr)) {
386 if (user_mode(regs)) {
387 force_sig(SIGSEGV);
388 return;
389 }
390
391 if ((entry = search_exception_tables(orig_pc))) {
392 regs->pc = entry->fixup;
393 return;
394 }
395
396 /* kernel access in kernel space, store it directly */
397 *((unsigned long *)vaddr) = regs->gpr[rb];
398 }
399
400 lwa_flag = 0;
401 regs->sr |= SPR_SR_F;
402 }
403
404 #define INSN_LWA 0x1b
405 #define INSN_SWA 0x33
406
do_illegal_instruction(struct pt_regs * regs,unsigned long address)407 asmlinkage void do_illegal_instruction(struct pt_regs *regs,
408 unsigned long address)
409 {
410 unsigned int op;
411 unsigned int insn = *((unsigned int *)address);
412
413 op = insn >> 26;
414
415 switch (op) {
416 case INSN_LWA:
417 simulate_lwa(regs, address, insn);
418 return;
419
420 case INSN_SWA:
421 simulate_swa(regs, address, insn);
422 return;
423
424 default:
425 break;
426 }
427
428 if (user_mode(regs)) {
429 /* Send a SIGILL */
430 force_sig_fault(SIGILL, ILL_ILLOPC, (void __user *)address);
431 } else { /* Kernel mode */
432 printk("KERNEL: Illegal instruction (SIGILL) 0x%.8lx\n",
433 address);
434 show_registers(regs);
435 die("Die:", regs, address);
436 }
437 }
438