1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * arch/alpha/kernel/traps.c
4 *
5 * (C) Copyright 1994 Linus Torvalds
6 */
7
8 /*
9 * This file initializes the trap entry points
10 */
11
12 #include <linux/cpu.h>
13 #include <linux/jiffies.h>
14 #include <linux/mm.h>
15 #include <linux/sched/signal.h>
16 #include <linux/sched/debug.h>
17 #include <linux/tty.h>
18 #include <linux/delay.h>
19 #include <linux/extable.h>
20 #include <linux/kallsyms.h>
21 #include <linux/ratelimit.h>
22
23 #include <asm/gentrap.h>
24 #include <linux/uaccess.h>
25 #include <asm/unaligned.h>
26 #include <asm/sysinfo.h>
27 #include <asm/hwrpb.h>
28 #include <asm/mmu_context.h>
29 #include <asm/special_insns.h>
30
31 #include "proto.h"
32
33 void
dik_show_regs(struct pt_regs * regs,unsigned long * r9_15)34 dik_show_regs(struct pt_regs *regs, unsigned long *r9_15)
35 {
36 printk("pc = [<%016lx>] ra = [<%016lx>] ps = %04lx %s\n",
37 regs->pc, regs->r26, regs->ps, print_tainted());
38 printk("pc is at %pSR\n", (void *)regs->pc);
39 printk("ra is at %pSR\n", (void *)regs->r26);
40 printk("v0 = %016lx t0 = %016lx t1 = %016lx\n",
41 regs->r0, regs->r1, regs->r2);
42 printk("t2 = %016lx t3 = %016lx t4 = %016lx\n",
43 regs->r3, regs->r4, regs->r5);
44 printk("t5 = %016lx t6 = %016lx t7 = %016lx\n",
45 regs->r6, regs->r7, regs->r8);
46
47 if (r9_15) {
48 printk("s0 = %016lx s1 = %016lx s2 = %016lx\n",
49 r9_15[9], r9_15[10], r9_15[11]);
50 printk("s3 = %016lx s4 = %016lx s5 = %016lx\n",
51 r9_15[12], r9_15[13], r9_15[14]);
52 printk("s6 = %016lx\n", r9_15[15]);
53 }
54
55 printk("a0 = %016lx a1 = %016lx a2 = %016lx\n",
56 regs->r16, regs->r17, regs->r18);
57 printk("a3 = %016lx a4 = %016lx a5 = %016lx\n",
58 regs->r19, regs->r20, regs->r21);
59 printk("t8 = %016lx t9 = %016lx t10= %016lx\n",
60 regs->r22, regs->r23, regs->r24);
61 printk("t11= %016lx pv = %016lx at = %016lx\n",
62 regs->r25, regs->r27, regs->r28);
63 printk("gp = %016lx sp = %p\n", regs->gp, regs+1);
64 #if 0
65 __halt();
66 #endif
67 }
68
69 #if 0
70 static char * ireg_name[] = {"v0", "t0", "t1", "t2", "t3", "t4", "t5", "t6",
71 "t7", "s0", "s1", "s2", "s3", "s4", "s5", "s6",
72 "a0", "a1", "a2", "a3", "a4", "a5", "t8", "t9",
73 "t10", "t11", "ra", "pv", "at", "gp", "sp", "zero"};
74 #endif
75
76 static void
dik_show_code(unsigned int * pc)77 dik_show_code(unsigned int *pc)
78 {
79 long i;
80
81 printk("Code:");
82 for (i = -6; i < 2; i++) {
83 unsigned int insn;
84 if (__get_user(insn, (unsigned int __user *)pc + i))
85 break;
86 printk("%c%08x%c", i ? ' ' : '<', insn, i ? ' ' : '>');
87 }
88 printk("\n");
89 }
90
91 static void
dik_show_trace(unsigned long * sp,const char * loglvl)92 dik_show_trace(unsigned long *sp, const char *loglvl)
93 {
94 long i = 0;
95 printk("%sTrace:\n", loglvl);
96 while (0x1ff8 & (unsigned long) sp) {
97 extern char _stext[], _etext[];
98 unsigned long tmp = *sp;
99 sp++;
100 if (!is_kernel_text(tmp))
101 continue;
102 printk("%s[<%lx>] %pSR\n", loglvl, tmp, (void *)tmp);
103 if (i > 40) {
104 printk("%s ...", loglvl);
105 break;
106 }
107 }
108 printk("%s\n", loglvl);
109 }
110
111 static int kstack_depth_to_print = 24;
112
show_stack(struct task_struct * task,unsigned long * sp,const char * loglvl)113 void show_stack(struct task_struct *task, unsigned long *sp, const char *loglvl)
114 {
115 unsigned long *stack;
116 int i;
117
118 /*
119 * debugging aid: "show_stack(NULL, NULL, KERN_EMERG);" prints the
120 * back trace for this cpu.
121 */
122 if(sp==NULL)
123 sp=(unsigned long*)&sp;
124
125 stack = sp;
126 for(i=0; i < kstack_depth_to_print; i++) {
127 if (((long) stack & (THREAD_SIZE-1)) == 0)
128 break;
129 if ((i % 4) == 0) {
130 if (i)
131 pr_cont("\n");
132 printk("%s ", loglvl);
133 } else {
134 pr_cont(" ");
135 }
136 pr_cont("%016lx", *stack++);
137 }
138 pr_cont("\n");
139 dik_show_trace(sp, loglvl);
140 }
141
142 void
die_if_kernel(char * str,struct pt_regs * regs,long err,unsigned long * r9_15)143 die_if_kernel(char * str, struct pt_regs *regs, long err, unsigned long *r9_15)
144 {
145 if (regs->ps & 8)
146 return;
147 #ifdef CONFIG_SMP
148 printk("CPU %d ", hard_smp_processor_id());
149 #endif
150 printk("%s(%d): %s %ld\n", current->comm, task_pid_nr(current), str, err);
151 dik_show_regs(regs, r9_15);
152 add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
153 dik_show_trace((unsigned long *)(regs+1), KERN_DEFAULT);
154 dik_show_code((unsigned int *)regs->pc);
155
156 if (test_and_set_thread_flag (TIF_DIE_IF_KERNEL)) {
157 printk("die_if_kernel recursion detected.\n");
158 local_irq_enable();
159 while (1);
160 }
161 make_task_dead(SIGSEGV);
162 }
163
164 #ifndef CONFIG_MATHEMU
dummy_emul(void)165 static long dummy_emul(void) { return 0; }
166 long (*alpha_fp_emul_imprecise)(struct pt_regs *regs, unsigned long writemask)
167 = (void *)dummy_emul;
168 EXPORT_SYMBOL_GPL(alpha_fp_emul_imprecise);
169 long (*alpha_fp_emul) (unsigned long pc)
170 = (void *)dummy_emul;
171 EXPORT_SYMBOL_GPL(alpha_fp_emul);
172 #else
173 long alpha_fp_emul_imprecise(struct pt_regs *regs, unsigned long writemask);
174 long alpha_fp_emul (unsigned long pc);
175 #endif
176
177 asmlinkage void
do_entArith(unsigned long summary,unsigned long write_mask,struct pt_regs * regs)178 do_entArith(unsigned long summary, unsigned long write_mask,
179 struct pt_regs *regs)
180 {
181 long si_code = FPE_FLTINV;
182
183 if (summary & 1) {
184 /* Software-completion summary bit is set, so try to
185 emulate the instruction. If the processor supports
186 precise exceptions, we don't have to search. */
187 if (!amask(AMASK_PRECISE_TRAP))
188 si_code = alpha_fp_emul(regs->pc - 4);
189 else
190 si_code = alpha_fp_emul_imprecise(regs, write_mask);
191 if (si_code == 0)
192 return;
193 }
194 die_if_kernel("Arithmetic fault", regs, 0, NULL);
195
196 send_sig_fault_trapno(SIGFPE, si_code, (void __user *) regs->pc, 0, current);
197 }
198
199 asmlinkage void
do_entIF(unsigned long type,struct pt_regs * regs)200 do_entIF(unsigned long type, struct pt_regs *regs)
201 {
202 int signo, code;
203
204 if (type == 3) { /* FEN fault */
205 /* Irritating users can call PAL_clrfen to disable the
206 FPU for the process. The kernel will then trap in
207 do_switch_stack and undo_switch_stack when we try
208 to save and restore the FP registers.
209
210 Given that GCC by default generates code that uses the
211 FP registers, PAL_clrfen is not useful except for DoS
212 attacks. So turn the bleeding FPU back on and be done
213 with it. */
214 current_thread_info()->pcb.flags |= 1;
215 __reload_thread(¤t_thread_info()->pcb);
216 return;
217 }
218 if (!user_mode(regs)) {
219 if (type == 1) {
220 const unsigned int *data
221 = (const unsigned int *) regs->pc;
222 printk("Kernel bug at %s:%d\n",
223 (const char *)(data[1] | (long)data[2] << 32),
224 data[0]);
225 }
226 #ifdef CONFIG_ALPHA_WTINT
227 if (type == 4) {
228 /* If CALL_PAL WTINT is totally unsupported by the
229 PALcode, e.g. MILO, "emulate" it by overwriting
230 the insn. */
231 unsigned int *pinsn
232 = (unsigned int *) regs->pc - 1;
233 if (*pinsn == PAL_wtint) {
234 *pinsn = 0x47e01400; /* mov 0,$0 */
235 imb();
236 regs->r0 = 0;
237 return;
238 }
239 }
240 #endif /* ALPHA_WTINT */
241 die_if_kernel((type == 1 ? "Kernel Bug" : "Instruction fault"),
242 regs, type, NULL);
243 }
244
245 switch (type) {
246 case 0: /* breakpoint */
247 if (ptrace_cancel_bpt(current)) {
248 regs->pc -= 4; /* make pc point to former bpt */
249 }
250
251 send_sig_fault(SIGTRAP, TRAP_BRKPT, (void __user *)regs->pc,
252 current);
253 return;
254
255 case 1: /* bugcheck */
256 send_sig_fault_trapno(SIGTRAP, TRAP_UNK,
257 (void __user *) regs->pc, 0, current);
258 return;
259
260 case 2: /* gentrap */
261 switch ((long) regs->r16) {
262 case GEN_INTOVF:
263 signo = SIGFPE;
264 code = FPE_INTOVF;
265 break;
266 case GEN_INTDIV:
267 signo = SIGFPE;
268 code = FPE_INTDIV;
269 break;
270 case GEN_FLTOVF:
271 signo = SIGFPE;
272 code = FPE_FLTOVF;
273 break;
274 case GEN_FLTDIV:
275 signo = SIGFPE;
276 code = FPE_FLTDIV;
277 break;
278 case GEN_FLTUND:
279 signo = SIGFPE;
280 code = FPE_FLTUND;
281 break;
282 case GEN_FLTINV:
283 signo = SIGFPE;
284 code = FPE_FLTINV;
285 break;
286 case GEN_FLTINE:
287 signo = SIGFPE;
288 code = FPE_FLTRES;
289 break;
290 case GEN_ROPRAND:
291 signo = SIGFPE;
292 code = FPE_FLTUNK;
293 break;
294
295 case GEN_DECOVF:
296 case GEN_DECDIV:
297 case GEN_DECINV:
298 case GEN_ASSERTERR:
299 case GEN_NULPTRERR:
300 case GEN_STKOVF:
301 case GEN_STRLENERR:
302 case GEN_SUBSTRERR:
303 case GEN_RANGERR:
304 case GEN_SUBRNG:
305 case GEN_SUBRNG1:
306 case GEN_SUBRNG2:
307 case GEN_SUBRNG3:
308 case GEN_SUBRNG4:
309 case GEN_SUBRNG5:
310 case GEN_SUBRNG6:
311 case GEN_SUBRNG7:
312 default:
313 signo = SIGTRAP;
314 code = TRAP_UNK;
315 break;
316 }
317
318 send_sig_fault_trapno(signo, code, (void __user *) regs->pc,
319 regs->r16, current);
320 return;
321
322 case 4: /* opDEC */
323 break;
324
325 case 5: /* illoc */
326 default: /* unexpected instruction-fault type */
327 ;
328 }
329
330 send_sig_fault(SIGILL, ILL_ILLOPC, (void __user *)regs->pc, current);
331 }
332
333 /* There is an ifdef in the PALcode in MILO that enables a
334 "kernel debugging entry point" as an unprivileged call_pal.
335
336 We don't want to have anything to do with it, but unfortunately
337 several versions of MILO included in distributions have it enabled,
338 and if we don't put something on the entry point we'll oops. */
339
340 asmlinkage void
do_entDbg(struct pt_regs * regs)341 do_entDbg(struct pt_regs *regs)
342 {
343 die_if_kernel("Instruction fault", regs, 0, NULL);
344
345 force_sig_fault(SIGILL, ILL_ILLOPC, (void __user *)regs->pc);
346 }
347
348
349 /*
350 * entUna has a different register layout to be reasonably simple. It
351 * needs access to all the integer registers (the kernel doesn't use
352 * fp-regs), and it needs to have them in order for simpler access.
353 *
354 * Due to the non-standard register layout (and because we don't want
355 * to handle floating-point regs), user-mode unaligned accesses are
356 * handled separately by do_entUnaUser below.
357 *
358 * Oh, btw, we don't handle the "gp" register correctly, but if we fault
359 * on a gp-register unaligned load/store, something is _very_ wrong
360 * in the kernel anyway..
361 */
362 struct allregs {
363 unsigned long regs[32];
364 unsigned long ps, pc, gp, a0, a1, a2;
365 };
366
367 struct unaligned_stat {
368 unsigned long count, va, pc;
369 } unaligned[2];
370
371
372 /* Macro for exception fixup code to access integer registers. */
373 #define una_reg(r) (_regs[(r) >= 16 && (r) <= 18 ? (r)+19 : (r)])
374
375
376 asmlinkage void
do_entUna(void * va,unsigned long opcode,unsigned long reg,struct allregs * regs)377 do_entUna(void * va, unsigned long opcode, unsigned long reg,
378 struct allregs *regs)
379 {
380 long error, tmp1, tmp2, tmp3, tmp4;
381 unsigned long pc = regs->pc - 4;
382 unsigned long *_regs = regs->regs;
383 const struct exception_table_entry *fixup;
384
385 unaligned[0].count++;
386 unaligned[0].va = (unsigned long) va;
387 unaligned[0].pc = pc;
388
389 /* We don't want to use the generic get/put unaligned macros as
390 we want to trap exceptions. Only if we actually get an
391 exception will we decide whether we should have caught it. */
392
393 switch (opcode) {
394 case 0x0c: /* ldwu */
395 __asm__ __volatile__(
396 "1: ldq_u %1,0(%3)\n"
397 "2: ldq_u %2,1(%3)\n"
398 " extwl %1,%3,%1\n"
399 " extwh %2,%3,%2\n"
400 "3:\n"
401 EXC(1b,3b,%1,%0)
402 EXC(2b,3b,%2,%0)
403 : "=r"(error), "=&r"(tmp1), "=&r"(tmp2)
404 : "r"(va), "0"(0));
405 if (error)
406 goto got_exception;
407 una_reg(reg) = tmp1|tmp2;
408 return;
409
410 case 0x28: /* ldl */
411 __asm__ __volatile__(
412 "1: ldq_u %1,0(%3)\n"
413 "2: ldq_u %2,3(%3)\n"
414 " extll %1,%3,%1\n"
415 " extlh %2,%3,%2\n"
416 "3:\n"
417 EXC(1b,3b,%1,%0)
418 EXC(2b,3b,%2,%0)
419 : "=r"(error), "=&r"(tmp1), "=&r"(tmp2)
420 : "r"(va), "0"(0));
421 if (error)
422 goto got_exception;
423 una_reg(reg) = (int)(tmp1|tmp2);
424 return;
425
426 case 0x29: /* ldq */
427 __asm__ __volatile__(
428 "1: ldq_u %1,0(%3)\n"
429 "2: ldq_u %2,7(%3)\n"
430 " extql %1,%3,%1\n"
431 " extqh %2,%3,%2\n"
432 "3:\n"
433 EXC(1b,3b,%1,%0)
434 EXC(2b,3b,%2,%0)
435 : "=r"(error), "=&r"(tmp1), "=&r"(tmp2)
436 : "r"(va), "0"(0));
437 if (error)
438 goto got_exception;
439 una_reg(reg) = tmp1|tmp2;
440 return;
441
442 /* Note that the store sequences do not indicate that they change
443 memory because it _should_ be affecting nothing in this context.
444 (Otherwise we have other, much larger, problems.) */
445 case 0x0d: /* stw */
446 __asm__ __volatile__(
447 "1: ldq_u %2,1(%5)\n"
448 "2: ldq_u %1,0(%5)\n"
449 " inswh %6,%5,%4\n"
450 " inswl %6,%5,%3\n"
451 " mskwh %2,%5,%2\n"
452 " mskwl %1,%5,%1\n"
453 " or %2,%4,%2\n"
454 " or %1,%3,%1\n"
455 "3: stq_u %2,1(%5)\n"
456 "4: stq_u %1,0(%5)\n"
457 "5:\n"
458 EXC(1b,5b,%2,%0)
459 EXC(2b,5b,%1,%0)
460 EXC(3b,5b,$31,%0)
461 EXC(4b,5b,$31,%0)
462 : "=r"(error), "=&r"(tmp1), "=&r"(tmp2),
463 "=&r"(tmp3), "=&r"(tmp4)
464 : "r"(va), "r"(una_reg(reg)), "0"(0));
465 if (error)
466 goto got_exception;
467 return;
468
469 case 0x2c: /* stl */
470 __asm__ __volatile__(
471 "1: ldq_u %2,3(%5)\n"
472 "2: ldq_u %1,0(%5)\n"
473 " inslh %6,%5,%4\n"
474 " insll %6,%5,%3\n"
475 " msklh %2,%5,%2\n"
476 " mskll %1,%5,%1\n"
477 " or %2,%4,%2\n"
478 " or %1,%3,%1\n"
479 "3: stq_u %2,3(%5)\n"
480 "4: stq_u %1,0(%5)\n"
481 "5:\n"
482 EXC(1b,5b,%2,%0)
483 EXC(2b,5b,%1,%0)
484 EXC(3b,5b,$31,%0)
485 EXC(4b,5b,$31,%0)
486 : "=r"(error), "=&r"(tmp1), "=&r"(tmp2),
487 "=&r"(tmp3), "=&r"(tmp4)
488 : "r"(va), "r"(una_reg(reg)), "0"(0));
489 if (error)
490 goto got_exception;
491 return;
492
493 case 0x2d: /* stq */
494 __asm__ __volatile__(
495 "1: ldq_u %2,7(%5)\n"
496 "2: ldq_u %1,0(%5)\n"
497 " insqh %6,%5,%4\n"
498 " insql %6,%5,%3\n"
499 " mskqh %2,%5,%2\n"
500 " mskql %1,%5,%1\n"
501 " or %2,%4,%2\n"
502 " or %1,%3,%1\n"
503 "3: stq_u %2,7(%5)\n"
504 "4: stq_u %1,0(%5)\n"
505 "5:\n"
506 EXC(1b,5b,%2,%0)
507 EXC(2b,5b,%1,%0)
508 EXC(3b,5b,$31,%0)
509 EXC(4b,5b,$31,%0)
510 : "=r"(error), "=&r"(tmp1), "=&r"(tmp2),
511 "=&r"(tmp3), "=&r"(tmp4)
512 : "r"(va), "r"(una_reg(reg)), "0"(0));
513 if (error)
514 goto got_exception;
515 return;
516 }
517
518 printk("Bad unaligned kernel access at %016lx: %p %lx %lu\n",
519 pc, va, opcode, reg);
520 make_task_dead(SIGSEGV);
521
522 got_exception:
523 /* Ok, we caught the exception, but we don't want it. Is there
524 someone to pass it along to? */
525 if ((fixup = search_exception_tables(pc)) != 0) {
526 unsigned long newpc;
527 newpc = fixup_exception(una_reg, fixup, pc);
528
529 printk("Forwarding unaligned exception at %lx (%lx)\n",
530 pc, newpc);
531
532 regs->pc = newpc;
533 return;
534 }
535
536 /*
537 * Yikes! No one to forward the exception to.
538 * Since the registers are in a weird format, dump them ourselves.
539 */
540
541 printk("%s(%d): unhandled unaligned exception\n",
542 current->comm, task_pid_nr(current));
543
544 printk("pc = [<%016lx>] ra = [<%016lx>] ps = %04lx\n",
545 pc, una_reg(26), regs->ps);
546 printk("r0 = %016lx r1 = %016lx r2 = %016lx\n",
547 una_reg(0), una_reg(1), una_reg(2));
548 printk("r3 = %016lx r4 = %016lx r5 = %016lx\n",
549 una_reg(3), una_reg(4), una_reg(5));
550 printk("r6 = %016lx r7 = %016lx r8 = %016lx\n",
551 una_reg(6), una_reg(7), una_reg(8));
552 printk("r9 = %016lx r10= %016lx r11= %016lx\n",
553 una_reg(9), una_reg(10), una_reg(11));
554 printk("r12= %016lx r13= %016lx r14= %016lx\n",
555 una_reg(12), una_reg(13), una_reg(14));
556 printk("r15= %016lx\n", una_reg(15));
557 printk("r16= %016lx r17= %016lx r18= %016lx\n",
558 una_reg(16), una_reg(17), una_reg(18));
559 printk("r19= %016lx r20= %016lx r21= %016lx\n",
560 una_reg(19), una_reg(20), una_reg(21));
561 printk("r22= %016lx r23= %016lx r24= %016lx\n",
562 una_reg(22), una_reg(23), una_reg(24));
563 printk("r25= %016lx r27= %016lx r28= %016lx\n",
564 una_reg(25), una_reg(27), una_reg(28));
565 printk("gp = %016lx sp = %p\n", regs->gp, regs+1);
566
567 dik_show_code((unsigned int *)pc);
568 dik_show_trace((unsigned long *)(regs+1), KERN_DEFAULT);
569
570 if (test_and_set_thread_flag (TIF_DIE_IF_KERNEL)) {
571 printk("die_if_kernel recursion detected.\n");
572 local_irq_enable();
573 while (1);
574 }
575 make_task_dead(SIGSEGV);
576 }
577
578 /*
579 * Convert an s-floating point value in memory format to the
580 * corresponding value in register format. The exponent
581 * needs to be remapped to preserve non-finite values
582 * (infinities, not-a-numbers, denormals).
583 */
584 static inline unsigned long
s_mem_to_reg(unsigned long s_mem)585 s_mem_to_reg (unsigned long s_mem)
586 {
587 unsigned long frac = (s_mem >> 0) & 0x7fffff;
588 unsigned long sign = (s_mem >> 31) & 0x1;
589 unsigned long exp_msb = (s_mem >> 30) & 0x1;
590 unsigned long exp_low = (s_mem >> 23) & 0x7f;
591 unsigned long exp;
592
593 exp = (exp_msb << 10) | exp_low; /* common case */
594 if (exp_msb) {
595 if (exp_low == 0x7f) {
596 exp = 0x7ff;
597 }
598 } else {
599 if (exp_low == 0x00) {
600 exp = 0x000;
601 } else {
602 exp |= (0x7 << 7);
603 }
604 }
605 return (sign << 63) | (exp << 52) | (frac << 29);
606 }
607
608 /*
609 * Convert an s-floating point value in register format to the
610 * corresponding value in memory format.
611 */
612 static inline unsigned long
s_reg_to_mem(unsigned long s_reg)613 s_reg_to_mem (unsigned long s_reg)
614 {
615 return ((s_reg >> 62) << 30) | ((s_reg << 5) >> 34);
616 }
617
618 /*
619 * Handle user-level unaligned fault. Handling user-level unaligned
620 * faults is *extremely* slow and produces nasty messages. A user
621 * program *should* fix unaligned faults ASAP.
622 *
623 * Notice that we have (almost) the regular kernel stack layout here,
624 * so finding the appropriate registers is a little more difficult
625 * than in the kernel case.
626 *
627 * Finally, we handle regular integer load/stores only. In
628 * particular, load-linked/store-conditionally and floating point
629 * load/stores are not supported. The former make no sense with
630 * unaligned faults (they are guaranteed to fail) and I don't think
631 * the latter will occur in any decent program.
632 *
633 * Sigh. We *do* have to handle some FP operations, because GCC will
634 * uses them as temporary storage for integer memory to memory copies.
635 * However, we need to deal with stt/ldt and sts/lds only.
636 */
637
638 #define OP_INT_MASK ( 1L << 0x28 | 1L << 0x2c /* ldl stl */ \
639 | 1L << 0x29 | 1L << 0x2d /* ldq stq */ \
640 | 1L << 0x0c | 1L << 0x0d /* ldwu stw */ \
641 | 1L << 0x0a | 1L << 0x0e ) /* ldbu stb */
642
643 #define OP_WRITE_MASK ( 1L << 0x26 | 1L << 0x27 /* sts stt */ \
644 | 1L << 0x2c | 1L << 0x2d /* stl stq */ \
645 | 1L << 0x0d | 1L << 0x0e ) /* stw stb */
646
647 #define R(x) ((size_t) &((struct pt_regs *)0)->x)
648
649 static int unauser_reg_offsets[32] = {
650 R(r0), R(r1), R(r2), R(r3), R(r4), R(r5), R(r6), R(r7), R(r8),
651 /* r9 ... r15 are stored in front of regs. */
652 -56, -48, -40, -32, -24, -16, -8,
653 R(r16), R(r17), R(r18),
654 R(r19), R(r20), R(r21), R(r22), R(r23), R(r24), R(r25), R(r26),
655 R(r27), R(r28), R(gp),
656 0, 0
657 };
658
659 #undef R
660
661 asmlinkage void
do_entUnaUser(void __user * va,unsigned long opcode,unsigned long reg,struct pt_regs * regs)662 do_entUnaUser(void __user * va, unsigned long opcode,
663 unsigned long reg, struct pt_regs *regs)
664 {
665 static DEFINE_RATELIMIT_STATE(ratelimit, 5 * HZ, 5);
666
667 unsigned long tmp1, tmp2, tmp3, tmp4;
668 unsigned long fake_reg, *reg_addr = &fake_reg;
669 int si_code;
670 long error;
671
672 /* Check the UAC bits to decide what the user wants us to do
673 with the unaligned access. */
674
675 if (!(current_thread_info()->status & TS_UAC_NOPRINT)) {
676 if (__ratelimit(&ratelimit)) {
677 printk("%s(%d): unaligned trap at %016lx: %p %lx %ld\n",
678 current->comm, task_pid_nr(current),
679 regs->pc - 4, va, opcode, reg);
680 }
681 }
682 if ((current_thread_info()->status & TS_UAC_SIGBUS))
683 goto give_sigbus;
684 /* Not sure why you'd want to use this, but... */
685 if ((current_thread_info()->status & TS_UAC_NOFIX))
686 return;
687
688 /* Don't bother reading ds in the access check since we already
689 know that this came from the user. Also rely on the fact that
690 the page at TASK_SIZE is unmapped and so can't be touched anyway. */
691 if ((unsigned long)va >= TASK_SIZE)
692 goto give_sigsegv;
693
694 ++unaligned[1].count;
695 unaligned[1].va = (unsigned long)va;
696 unaligned[1].pc = regs->pc - 4;
697
698 if ((1L << opcode) & OP_INT_MASK) {
699 /* it's an integer load/store */
700 if (reg < 30) {
701 reg_addr = (unsigned long *)
702 ((char *)regs + unauser_reg_offsets[reg]);
703 } else if (reg == 30) {
704 /* usp in PAL regs */
705 fake_reg = rdusp();
706 } else {
707 /* zero "register" */
708 fake_reg = 0;
709 }
710 }
711
712 /* We don't want to use the generic get/put unaligned macros as
713 we want to trap exceptions. Only if we actually get an
714 exception will we decide whether we should have caught it. */
715
716 switch (opcode) {
717 case 0x0c: /* ldwu */
718 __asm__ __volatile__(
719 "1: ldq_u %1,0(%3)\n"
720 "2: ldq_u %2,1(%3)\n"
721 " extwl %1,%3,%1\n"
722 " extwh %2,%3,%2\n"
723 "3:\n"
724 EXC(1b,3b,%1,%0)
725 EXC(2b,3b,%2,%0)
726 : "=r"(error), "=&r"(tmp1), "=&r"(tmp2)
727 : "r"(va), "0"(0));
728 if (error)
729 goto give_sigsegv;
730 *reg_addr = tmp1|tmp2;
731 break;
732
733 case 0x22: /* lds */
734 __asm__ __volatile__(
735 "1: ldq_u %1,0(%3)\n"
736 "2: ldq_u %2,3(%3)\n"
737 " extll %1,%3,%1\n"
738 " extlh %2,%3,%2\n"
739 "3:\n"
740 EXC(1b,3b,%1,%0)
741 EXC(2b,3b,%2,%0)
742 : "=r"(error), "=&r"(tmp1), "=&r"(tmp2)
743 : "r"(va), "0"(0));
744 if (error)
745 goto give_sigsegv;
746 alpha_write_fp_reg(reg, s_mem_to_reg((int)(tmp1|tmp2)));
747 return;
748
749 case 0x23: /* ldt */
750 __asm__ __volatile__(
751 "1: ldq_u %1,0(%3)\n"
752 "2: ldq_u %2,7(%3)\n"
753 " extql %1,%3,%1\n"
754 " extqh %2,%3,%2\n"
755 "3:\n"
756 EXC(1b,3b,%1,%0)
757 EXC(2b,3b,%2,%0)
758 : "=r"(error), "=&r"(tmp1), "=&r"(tmp2)
759 : "r"(va), "0"(0));
760 if (error)
761 goto give_sigsegv;
762 alpha_write_fp_reg(reg, tmp1|tmp2);
763 return;
764
765 case 0x28: /* ldl */
766 __asm__ __volatile__(
767 "1: ldq_u %1,0(%3)\n"
768 "2: ldq_u %2,3(%3)\n"
769 " extll %1,%3,%1\n"
770 " extlh %2,%3,%2\n"
771 "3:\n"
772 EXC(1b,3b,%1,%0)
773 EXC(2b,3b,%2,%0)
774 : "=r"(error), "=&r"(tmp1), "=&r"(tmp2)
775 : "r"(va), "0"(0));
776 if (error)
777 goto give_sigsegv;
778 *reg_addr = (int)(tmp1|tmp2);
779 break;
780
781 case 0x29: /* ldq */
782 __asm__ __volatile__(
783 "1: ldq_u %1,0(%3)\n"
784 "2: ldq_u %2,7(%3)\n"
785 " extql %1,%3,%1\n"
786 " extqh %2,%3,%2\n"
787 "3:\n"
788 EXC(1b,3b,%1,%0)
789 EXC(2b,3b,%2,%0)
790 : "=r"(error), "=&r"(tmp1), "=&r"(tmp2)
791 : "r"(va), "0"(0));
792 if (error)
793 goto give_sigsegv;
794 *reg_addr = tmp1|tmp2;
795 break;
796
797 /* Note that the store sequences do not indicate that they change
798 memory because it _should_ be affecting nothing in this context.
799 (Otherwise we have other, much larger, problems.) */
800 case 0x0d: /* stw */
801 __asm__ __volatile__(
802 "1: ldq_u %2,1(%5)\n"
803 "2: ldq_u %1,0(%5)\n"
804 " inswh %6,%5,%4\n"
805 " inswl %6,%5,%3\n"
806 " mskwh %2,%5,%2\n"
807 " mskwl %1,%5,%1\n"
808 " or %2,%4,%2\n"
809 " or %1,%3,%1\n"
810 "3: stq_u %2,1(%5)\n"
811 "4: stq_u %1,0(%5)\n"
812 "5:\n"
813 EXC(1b,5b,%2,%0)
814 EXC(2b,5b,%1,%0)
815 EXC(3b,5b,$31,%0)
816 EXC(4b,5b,$31,%0)
817 : "=r"(error), "=&r"(tmp1), "=&r"(tmp2),
818 "=&r"(tmp3), "=&r"(tmp4)
819 : "r"(va), "r"(*reg_addr), "0"(0));
820 if (error)
821 goto give_sigsegv;
822 return;
823
824 case 0x26: /* sts */
825 fake_reg = s_reg_to_mem(alpha_read_fp_reg(reg));
826 fallthrough;
827
828 case 0x2c: /* stl */
829 __asm__ __volatile__(
830 "1: ldq_u %2,3(%5)\n"
831 "2: ldq_u %1,0(%5)\n"
832 " inslh %6,%5,%4\n"
833 " insll %6,%5,%3\n"
834 " msklh %2,%5,%2\n"
835 " mskll %1,%5,%1\n"
836 " or %2,%4,%2\n"
837 " or %1,%3,%1\n"
838 "3: stq_u %2,3(%5)\n"
839 "4: stq_u %1,0(%5)\n"
840 "5:\n"
841 EXC(1b,5b,%2,%0)
842 EXC(2b,5b,%1,%0)
843 EXC(3b,5b,$31,%0)
844 EXC(4b,5b,$31,%0)
845 : "=r"(error), "=&r"(tmp1), "=&r"(tmp2),
846 "=&r"(tmp3), "=&r"(tmp4)
847 : "r"(va), "r"(*reg_addr), "0"(0));
848 if (error)
849 goto give_sigsegv;
850 return;
851
852 case 0x27: /* stt */
853 fake_reg = alpha_read_fp_reg(reg);
854 fallthrough;
855
856 case 0x2d: /* stq */
857 __asm__ __volatile__(
858 "1: ldq_u %2,7(%5)\n"
859 "2: ldq_u %1,0(%5)\n"
860 " insqh %6,%5,%4\n"
861 " insql %6,%5,%3\n"
862 " mskqh %2,%5,%2\n"
863 " mskql %1,%5,%1\n"
864 " or %2,%4,%2\n"
865 " or %1,%3,%1\n"
866 "3: stq_u %2,7(%5)\n"
867 "4: stq_u %1,0(%5)\n"
868 "5:\n"
869 EXC(1b,5b,%2,%0)
870 EXC(2b,5b,%1,%0)
871 EXC(3b,5b,$31,%0)
872 EXC(4b,5b,$31,%0)
873 : "=r"(error), "=&r"(tmp1), "=&r"(tmp2),
874 "=&r"(tmp3), "=&r"(tmp4)
875 : "r"(va), "r"(*reg_addr), "0"(0));
876 if (error)
877 goto give_sigsegv;
878 return;
879
880 default:
881 /* What instruction were you trying to use, exactly? */
882 goto give_sigbus;
883 }
884
885 /* Only integer loads should get here; everyone else returns early. */
886 if (reg == 30)
887 wrusp(fake_reg);
888 return;
889
890 give_sigsegv:
891 regs->pc -= 4; /* make pc point to faulting insn */
892
893 /* We need to replicate some of the logic in mm/fault.c,
894 since we don't have access to the fault code in the
895 exception handling return path. */
896 if ((unsigned long)va >= TASK_SIZE)
897 si_code = SEGV_ACCERR;
898 else {
899 struct mm_struct *mm = current->mm;
900 mmap_read_lock(mm);
901 if (find_vma(mm, (unsigned long)va))
902 si_code = SEGV_ACCERR;
903 else
904 si_code = SEGV_MAPERR;
905 mmap_read_unlock(mm);
906 }
907 send_sig_fault(SIGSEGV, si_code, va, current);
908 return;
909
910 give_sigbus:
911 regs->pc -= 4;
912 send_sig_fault(SIGBUS, BUS_ADRALN, va, current);
913 return;
914 }
915
916 void
trap_init(void)917 trap_init(void)
918 {
919 /* Tell PAL-code what global pointer we want in the kernel. */
920 register unsigned long gptr __asm__("$29");
921 wrkgp(gptr);
922
923 wrent(entArith, 1);
924 wrent(entMM, 2);
925 wrent(entIF, 3);
926 wrent(entUna, 4);
927 wrent(entSys, 5);
928 wrent(entDbg, 6);
929 }
930