1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Author: Huacai Chen <chenhuacai@loongson.cn>
4 * Copyright (C) 2020-2022 Loongson Technology Corporation Limited
5 */
6 #include <linux/bitfield.h>
7 #include <linux/bitops.h>
8 #include <linux/bug.h>
9 #include <linux/compiler.h>
10 #include <linux/context_tracking.h>
11 #include <linux/entry-common.h>
12 #include <linux/init.h>
13 #include <linux/kernel.h>
14 #include <linux/kexec.h>
15 #include <linux/module.h>
16 #include <linux/extable.h>
17 #include <linux/mm.h>
18 #include <linux/sched/mm.h>
19 #include <linux/sched/debug.h>
20 #include <linux/smp.h>
21 #include <linux/spinlock.h>
22 #include <linux/kallsyms.h>
23 #include <linux/memblock.h>
24 #include <linux/interrupt.h>
25 #include <linux/ptrace.h>
26 #include <linux/kgdb.h>
27 #include <linux/kdebug.h>
28 #include <linux/notifier.h>
29 #include <linux/irq.h>
30 #include <linux/perf_event.h>
31
32 #include <asm/addrspace.h>
33 #include <asm/bootinfo.h>
34 #include <asm/branch.h>
35 #include <asm/break.h>
36 #include <asm/cpu.h>
37 #include <asm/exception.h>
38 #include <asm/fpu.h>
39 #include <asm/lbt.h>
40 #include <asm/inst.h>
41 #include <asm/kgdb.h>
42 #include <asm/loongarch.h>
43 #include <asm/mmu_context.h>
44 #include <asm/pgtable.h>
45 #include <asm/ptrace.h>
46 #include <asm/sections.h>
47 #include <asm/siginfo.h>
48 #include <asm/stacktrace.h>
49 #include <asm/tlb.h>
50 #include <asm/types.h>
51 #include <asm/unwind.h>
52 #include <asm/uprobes.h>
53
54 #include "access-helper.h"
55
show_backtrace(struct task_struct * task,const struct pt_regs * regs,const char * loglvl,bool user)56 static void show_backtrace(struct task_struct *task, const struct pt_regs *regs,
57 const char *loglvl, bool user)
58 {
59 unsigned long addr;
60 struct unwind_state state;
61 struct pt_regs *pregs = (struct pt_regs *)regs;
62
63 if (!task)
64 task = current;
65
66 printk("%sCall Trace:", loglvl);
67 for (unwind_start(&state, task, pregs);
68 !unwind_done(&state); unwind_next_frame(&state)) {
69 addr = unwind_get_return_address(&state);
70 print_ip_sym(loglvl, addr);
71 }
72 printk("%s\n", loglvl);
73 }
74
show_stacktrace(struct task_struct * task,const struct pt_regs * regs,const char * loglvl,bool user)75 static void show_stacktrace(struct task_struct *task,
76 const struct pt_regs *regs, const char *loglvl, bool user)
77 {
78 int i;
79 const int field = 2 * sizeof(unsigned long);
80 unsigned long stackdata;
81 unsigned long *sp = (unsigned long *)regs->regs[3];
82
83 printk("%sStack :", loglvl);
84 i = 0;
85 while ((unsigned long) sp & (PAGE_SIZE - 1)) {
86 if (i && ((i % (64 / field)) == 0)) {
87 pr_cont("\n");
88 printk("%s ", loglvl);
89 }
90 if (i > 39) {
91 pr_cont(" ...");
92 break;
93 }
94
95 if (__get_addr(&stackdata, sp++, user)) {
96 pr_cont(" (Bad stack address)");
97 break;
98 }
99
100 pr_cont(" %0*lx", field, stackdata);
101 i++;
102 }
103 pr_cont("\n");
104 show_backtrace(task, regs, loglvl, user);
105 }
106
show_stack(struct task_struct * task,unsigned long * sp,const char * loglvl)107 void show_stack(struct task_struct *task, unsigned long *sp, const char *loglvl)
108 {
109 struct pt_regs regs;
110
111 regs.csr_crmd = 0;
112 if (sp) {
113 regs.csr_era = 0;
114 regs.regs[1] = 0;
115 regs.regs[3] = (unsigned long)sp;
116 } else {
117 if (!task || task == current)
118 prepare_frametrace(®s);
119 else {
120 regs.csr_era = task->thread.reg01;
121 regs.regs[1] = 0;
122 regs.regs[3] = task->thread.reg03;
123 regs.regs[22] = task->thread.reg22;
124 }
125 }
126
127 show_stacktrace(task, ®s, loglvl, false);
128 }
129
show_code(unsigned int * pc,bool user)130 static void show_code(unsigned int *pc, bool user)
131 {
132 long i;
133 unsigned int insn;
134
135 printk("Code:");
136
137 for(i = -3 ; i < 6 ; i++) {
138 if (__get_inst(&insn, pc + i, user)) {
139 pr_cont(" (Bad address in era)\n");
140 break;
141 }
142 pr_cont("%c%08x%c", (i?' ':'<'), insn, (i?' ':'>'));
143 }
144 pr_cont("\n");
145 }
146
print_bool_fragment(const char * key,unsigned long val,bool first)147 static void print_bool_fragment(const char *key, unsigned long val, bool first)
148 {
149 /* e.g. "+PG", "-DA" */
150 pr_cont("%s%c%s", first ? "" : " ", val ? '+' : '-', key);
151 }
152
print_plv_fragment(const char * key,int val)153 static void print_plv_fragment(const char *key, int val)
154 {
155 /* e.g. "PLV0", "PPLV3" */
156 pr_cont("%s%d", key, val);
157 }
158
print_memory_type_fragment(const char * key,unsigned long val)159 static void print_memory_type_fragment(const char *key, unsigned long val)
160 {
161 const char *humanized_type;
162
163 switch (val) {
164 case 0:
165 humanized_type = "SUC";
166 break;
167 case 1:
168 humanized_type = "CC";
169 break;
170 case 2:
171 humanized_type = "WUC";
172 break;
173 default:
174 pr_cont(" %s=Reserved(%lu)", key, val);
175 return;
176 }
177
178 /* e.g. " DATM=WUC" */
179 pr_cont(" %s=%s", key, humanized_type);
180 }
181
print_intr_fragment(const char * key,unsigned long val)182 static void print_intr_fragment(const char *key, unsigned long val)
183 {
184 /* e.g. "LIE=0-1,3,5-7" */
185 pr_cont("%s=%*pbl", key, EXCCODE_INT_NUM, &val);
186 }
187
print_crmd(unsigned long x)188 static void print_crmd(unsigned long x)
189 {
190 printk(" CRMD: %08lx (", x);
191 print_plv_fragment("PLV", (int) FIELD_GET(CSR_CRMD_PLV, x));
192 print_bool_fragment("IE", FIELD_GET(CSR_CRMD_IE, x), false);
193 print_bool_fragment("DA", FIELD_GET(CSR_CRMD_DA, x), false);
194 print_bool_fragment("PG", FIELD_GET(CSR_CRMD_PG, x), false);
195 print_memory_type_fragment("DACF", FIELD_GET(CSR_CRMD_DACF, x));
196 print_memory_type_fragment("DACM", FIELD_GET(CSR_CRMD_DACM, x));
197 print_bool_fragment("WE", FIELD_GET(CSR_CRMD_WE, x), false);
198 pr_cont(")\n");
199 }
200
print_prmd(unsigned long x)201 static void print_prmd(unsigned long x)
202 {
203 printk(" PRMD: %08lx (", x);
204 print_plv_fragment("PPLV", (int) FIELD_GET(CSR_PRMD_PPLV, x));
205 print_bool_fragment("PIE", FIELD_GET(CSR_PRMD_PIE, x), false);
206 print_bool_fragment("PWE", FIELD_GET(CSR_PRMD_PWE, x), false);
207 pr_cont(")\n");
208 }
209
print_euen(unsigned long x)210 static void print_euen(unsigned long x)
211 {
212 printk(" EUEN: %08lx (", x);
213 print_bool_fragment("FPE", FIELD_GET(CSR_EUEN_FPEN, x), true);
214 print_bool_fragment("SXE", FIELD_GET(CSR_EUEN_LSXEN, x), false);
215 print_bool_fragment("ASXE", FIELD_GET(CSR_EUEN_LASXEN, x), false);
216 print_bool_fragment("BTE", FIELD_GET(CSR_EUEN_LBTEN, x), false);
217 pr_cont(")\n");
218 }
219
print_ecfg(unsigned long x)220 static void print_ecfg(unsigned long x)
221 {
222 printk(" ECFG: %08lx (", x);
223 print_intr_fragment("LIE", FIELD_GET(CSR_ECFG_IM, x));
224 pr_cont(" VS=%d)\n", (int) FIELD_GET(CSR_ECFG_VS, x));
225 }
226
humanize_exc_name(unsigned int ecode,unsigned int esubcode)227 static const char *humanize_exc_name(unsigned int ecode, unsigned int esubcode)
228 {
229 /*
230 * LoongArch users and developers are probably more familiar with
231 * those names found in the ISA manual, so we are going to print out
232 * the latter. This will require some mapping.
233 */
234 switch (ecode) {
235 case EXCCODE_RSV: return "INT";
236 case EXCCODE_TLBL: return "PIL";
237 case EXCCODE_TLBS: return "PIS";
238 case EXCCODE_TLBI: return "PIF";
239 case EXCCODE_TLBM: return "PME";
240 case EXCCODE_TLBNR: return "PNR";
241 case EXCCODE_TLBNX: return "PNX";
242 case EXCCODE_TLBPE: return "PPI";
243 case EXCCODE_ADE:
244 switch (esubcode) {
245 case EXSUBCODE_ADEF: return "ADEF";
246 case EXSUBCODE_ADEM: return "ADEM";
247 }
248 break;
249 case EXCCODE_ALE: return "ALE";
250 case EXCCODE_BCE: return "BCE";
251 case EXCCODE_SYS: return "SYS";
252 case EXCCODE_BP: return "BRK";
253 case EXCCODE_INE: return "INE";
254 case EXCCODE_IPE: return "IPE";
255 case EXCCODE_FPDIS: return "FPD";
256 case EXCCODE_LSXDIS: return "SXD";
257 case EXCCODE_LASXDIS: return "ASXD";
258 case EXCCODE_FPE:
259 switch (esubcode) {
260 case EXCSUBCODE_FPE: return "FPE";
261 case EXCSUBCODE_VFPE: return "VFPE";
262 }
263 break;
264 case EXCCODE_WATCH:
265 switch (esubcode) {
266 case EXCSUBCODE_WPEF: return "WPEF";
267 case EXCSUBCODE_WPEM: return "WPEM";
268 }
269 break;
270 case EXCCODE_BTDIS: return "BTD";
271 case EXCCODE_BTE: return "BTE";
272 case EXCCODE_GSPR: return "GSPR";
273 case EXCCODE_HVC: return "HVC";
274 case EXCCODE_GCM:
275 switch (esubcode) {
276 case EXCSUBCODE_GCSC: return "GCSC";
277 case EXCSUBCODE_GCHC: return "GCHC";
278 }
279 break;
280 /*
281 * The manual did not mention the EXCCODE_SE case, but print out it
282 * nevertheless.
283 */
284 case EXCCODE_SE: return "SE";
285 }
286
287 return "???";
288 }
289
print_estat(unsigned long x)290 static void print_estat(unsigned long x)
291 {
292 unsigned int ecode = FIELD_GET(CSR_ESTAT_EXC, x);
293 unsigned int esubcode = FIELD_GET(CSR_ESTAT_ESUBCODE, x);
294
295 printk("ESTAT: %08lx [%s] (", x, humanize_exc_name(ecode, esubcode));
296 print_intr_fragment("IS", FIELD_GET(CSR_ESTAT_IS, x));
297 pr_cont(" ECode=%d EsubCode=%d)\n", (int) ecode, (int) esubcode);
298 }
299
__show_regs(const struct pt_regs * regs)300 static void __show_regs(const struct pt_regs *regs)
301 {
302 const int field = 2 * sizeof(unsigned long);
303 unsigned int exccode = FIELD_GET(CSR_ESTAT_EXC, regs->csr_estat);
304
305 show_regs_print_info(KERN_DEFAULT);
306
307 /* Print saved GPRs except $zero (substituting with PC/ERA) */
308 #define GPR_FIELD(x) field, regs->regs[x]
309 printk("pc %0*lx ra %0*lx tp %0*lx sp %0*lx\n",
310 field, regs->csr_era, GPR_FIELD(1), GPR_FIELD(2), GPR_FIELD(3));
311 printk("a0 %0*lx a1 %0*lx a2 %0*lx a3 %0*lx\n",
312 GPR_FIELD(4), GPR_FIELD(5), GPR_FIELD(6), GPR_FIELD(7));
313 printk("a4 %0*lx a5 %0*lx a6 %0*lx a7 %0*lx\n",
314 GPR_FIELD(8), GPR_FIELD(9), GPR_FIELD(10), GPR_FIELD(11));
315 printk("t0 %0*lx t1 %0*lx t2 %0*lx t3 %0*lx\n",
316 GPR_FIELD(12), GPR_FIELD(13), GPR_FIELD(14), GPR_FIELD(15));
317 printk("t4 %0*lx t5 %0*lx t6 %0*lx t7 %0*lx\n",
318 GPR_FIELD(16), GPR_FIELD(17), GPR_FIELD(18), GPR_FIELD(19));
319 printk("t8 %0*lx u0 %0*lx s9 %0*lx s0 %0*lx\n",
320 GPR_FIELD(20), GPR_FIELD(21), GPR_FIELD(22), GPR_FIELD(23));
321 printk("s1 %0*lx s2 %0*lx s3 %0*lx s4 %0*lx\n",
322 GPR_FIELD(24), GPR_FIELD(25), GPR_FIELD(26), GPR_FIELD(27));
323 printk("s5 %0*lx s6 %0*lx s7 %0*lx s8 %0*lx\n",
324 GPR_FIELD(28), GPR_FIELD(29), GPR_FIELD(30), GPR_FIELD(31));
325
326 /* The slot for $zero is reused as the syscall restart flag */
327 if (regs->regs[0])
328 printk("syscall restart flag: %0*lx\n", GPR_FIELD(0));
329
330 if (user_mode(regs)) {
331 printk(" ra: %0*lx\n", GPR_FIELD(1));
332 printk(" ERA: %0*lx\n", field, regs->csr_era);
333 } else {
334 printk(" ra: %0*lx %pS\n", GPR_FIELD(1), (void *) regs->regs[1]);
335 printk(" ERA: %0*lx %pS\n", field, regs->csr_era, (void *) regs->csr_era);
336 }
337 #undef GPR_FIELD
338
339 /* Print saved important CSRs */
340 print_crmd(regs->csr_crmd);
341 print_prmd(regs->csr_prmd);
342 print_euen(regs->csr_euen);
343 print_ecfg(regs->csr_ecfg);
344 print_estat(regs->csr_estat);
345
346 if (exccode >= EXCCODE_TLBL && exccode <= EXCCODE_ALE)
347 printk(" BADV: %0*lx\n", field, regs->csr_badvaddr);
348
349 printk(" PRID: %08x (%s, %s)\n", read_cpucfg(LOONGARCH_CPUCFG0),
350 cpu_family_string(), cpu_full_name_string());
351 }
352
show_regs(struct pt_regs * regs)353 void show_regs(struct pt_regs *regs)
354 {
355 __show_regs((struct pt_regs *)regs);
356 dump_stack();
357 }
358
show_registers(struct pt_regs * regs)359 void show_registers(struct pt_regs *regs)
360 {
361 __show_regs(regs);
362 print_modules();
363 printk("Process %s (pid: %d, threadinfo=%p, task=%p)\n",
364 current->comm, current->pid, current_thread_info(), current);
365
366 show_stacktrace(current, regs, KERN_DEFAULT, user_mode(regs));
367 show_code((void *)regs->csr_era, user_mode(regs));
368 printk("\n");
369 }
370
371 static DEFINE_RAW_SPINLOCK(die_lock);
372
die(const char * str,struct pt_regs * regs)373 void die(const char *str, struct pt_regs *regs)
374 {
375 int ret;
376 static int die_counter;
377
378 oops_enter();
379
380 ret = notify_die(DIE_OOPS, str, regs, 0,
381 current->thread.trap_nr, SIGSEGV);
382
383 console_verbose();
384 raw_spin_lock_irq(&die_lock);
385 bust_spinlocks(1);
386
387 printk("%s[#%d]:\n", str, ++die_counter);
388 show_registers(regs);
389 add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
390 raw_spin_unlock_irq(&die_lock);
391
392 oops_exit();
393
394 if (ret == NOTIFY_STOP)
395 return;
396
397 if (regs && kexec_should_crash(current))
398 crash_kexec(regs);
399
400 if (in_interrupt())
401 panic("Fatal exception in interrupt");
402
403 if (panic_on_oops)
404 panic("Fatal exception");
405
406 make_task_dead(SIGSEGV);
407 }
408
setup_vint_size(unsigned int size)409 static inline void setup_vint_size(unsigned int size)
410 {
411 unsigned int vs;
412
413 vs = ilog2(size/4);
414
415 if (vs == 0 || vs > 7)
416 panic("vint_size %d Not support yet", vs);
417
418 csr_xchg32(vs<<CSR_ECFG_VS_SHIFT, CSR_ECFG_VS, LOONGARCH_CSR_ECFG);
419 }
420
421 /*
422 * Send SIGFPE according to FCSR Cause bits, which must have already
423 * been masked against Enable bits. This is impotant as Inexact can
424 * happen together with Overflow or Underflow, and `ptrace' can set
425 * any bits.
426 */
force_fcsr_sig(unsigned long fcsr,void __user * fault_addr,struct task_struct * tsk)427 static void force_fcsr_sig(unsigned long fcsr,
428 void __user *fault_addr, struct task_struct *tsk)
429 {
430 int si_code = FPE_FLTUNK;
431
432 if (fcsr & FPU_CSR_INV_X)
433 si_code = FPE_FLTINV;
434 else if (fcsr & FPU_CSR_DIV_X)
435 si_code = FPE_FLTDIV;
436 else if (fcsr & FPU_CSR_OVF_X)
437 si_code = FPE_FLTOVF;
438 else if (fcsr & FPU_CSR_UDF_X)
439 si_code = FPE_FLTUND;
440 else if (fcsr & FPU_CSR_INE_X)
441 si_code = FPE_FLTRES;
442
443 force_sig_fault(SIGFPE, si_code, fault_addr);
444 }
445
process_fpemu_return(int sig,void __user * fault_addr,unsigned long fcsr)446 static int process_fpemu_return(int sig, void __user *fault_addr, unsigned long fcsr)
447 {
448 int si_code;
449
450 switch (sig) {
451 case 0:
452 return 0;
453
454 case SIGFPE:
455 force_fcsr_sig(fcsr, fault_addr, current);
456 return 1;
457
458 case SIGBUS:
459 force_sig_fault(SIGBUS, BUS_ADRERR, fault_addr);
460 return 1;
461
462 case SIGSEGV:
463 mmap_read_lock(current->mm);
464 if (vma_lookup(current->mm, (unsigned long)fault_addr))
465 si_code = SEGV_ACCERR;
466 else
467 si_code = SEGV_MAPERR;
468 mmap_read_unlock(current->mm);
469 force_sig_fault(SIGSEGV, si_code, fault_addr);
470 return 1;
471
472 default:
473 force_sig(sig);
474 return 1;
475 }
476 }
477
478 /*
479 * Delayed fp exceptions when doing a lazy ctx switch
480 */
do_fpe(struct pt_regs * regs,unsigned long fcsr)481 asmlinkage void noinstr do_fpe(struct pt_regs *regs, unsigned long fcsr)
482 {
483 int sig;
484 void __user *fault_addr;
485 irqentry_state_t state = irqentry_enter(regs);
486
487 if (notify_die(DIE_FP, "FP exception", regs, 0, current->thread.trap_nr,
488 SIGFPE) == NOTIFY_STOP)
489 goto out;
490
491 /* Clear FCSR.Cause before enabling interrupts */
492 write_fcsr(LOONGARCH_FCSR0, fcsr & ~mask_fcsr_x(fcsr));
493 local_irq_enable();
494
495 die_if_kernel("FP exception in kernel code", regs);
496
497 sig = SIGFPE;
498 fault_addr = (void __user *) regs->csr_era;
499
500 /* Send a signal if required. */
501 process_fpemu_return(sig, fault_addr, fcsr);
502
503 out:
504 local_irq_disable();
505 irqentry_exit(regs, state);
506 }
507
do_ade(struct pt_regs * regs)508 asmlinkage void noinstr do_ade(struct pt_regs *regs)
509 {
510 irqentry_state_t state = irqentry_enter(regs);
511
512 die_if_kernel("Kernel ade access", regs);
513 force_sig_fault(SIGBUS, BUS_ADRERR, (void __user *)regs->csr_badvaddr);
514
515 irqentry_exit(regs, state);
516 }
517
518 /* sysctl hooks */
519 int unaligned_enabled __read_mostly = 1; /* Enabled by default */
520 int no_unaligned_warning __read_mostly = 1; /* Only 1 warning by default */
521
do_ale(struct pt_regs * regs)522 asmlinkage void noinstr do_ale(struct pt_regs *regs)
523 {
524 irqentry_state_t state = irqentry_enter(regs);
525
526 #ifndef CONFIG_ARCH_STRICT_ALIGN
527 die_if_kernel("Kernel ale access", regs);
528 force_sig_fault(SIGBUS, BUS_ADRALN, (void __user *)regs->csr_badvaddr);
529 #else
530 bool pie = regs_irqs_disabled(regs);
531 unsigned int *pc;
532
533 if (!pie)
534 local_irq_enable();
535
536 perf_sw_event(PERF_COUNT_SW_ALIGNMENT_FAULTS, 1, regs, regs->csr_badvaddr);
537
538 /*
539 * Did we catch a fault trying to load an instruction?
540 */
541 if (regs->csr_badvaddr == regs->csr_era)
542 goto sigbus;
543 if (user_mode(regs) && !test_thread_flag(TIF_FIXADE))
544 goto sigbus;
545 if (!unaligned_enabled)
546 goto sigbus;
547 if (!no_unaligned_warning)
548 show_registers(regs);
549
550 pc = (unsigned int *)exception_era(regs);
551
552 emulate_load_store_insn(regs, (void __user *)regs->csr_badvaddr, pc);
553
554 goto out;
555
556 sigbus:
557 die_if_kernel("Kernel ale access", regs);
558 force_sig_fault(SIGBUS, BUS_ADRALN, (void __user *)regs->csr_badvaddr);
559 out:
560 if (!pie)
561 local_irq_disable();
562 #endif
563 irqentry_exit(regs, state);
564 }
565
566 #ifdef CONFIG_GENERIC_BUG
is_valid_bugaddr(unsigned long addr)567 int is_valid_bugaddr(unsigned long addr)
568 {
569 return 1;
570 }
571 #endif /* CONFIG_GENERIC_BUG */
572
bug_handler(struct pt_regs * regs)573 static void bug_handler(struct pt_regs *regs)
574 {
575 switch (report_bug(regs->csr_era, regs)) {
576 case BUG_TRAP_TYPE_BUG:
577 case BUG_TRAP_TYPE_NONE:
578 die_if_kernel("Oops - BUG", regs);
579 force_sig(SIGTRAP);
580 break;
581
582 case BUG_TRAP_TYPE_WARN:
583 /* Skip the BUG instruction and continue */
584 regs->csr_era += LOONGARCH_INSN_SIZE;
585 break;
586 }
587 }
588
do_bce(struct pt_regs * regs)589 asmlinkage void noinstr do_bce(struct pt_regs *regs)
590 {
591 bool user = user_mode(regs);
592 bool pie = regs_irqs_disabled(regs);
593 unsigned long era = exception_era(regs);
594 u64 badv = 0, lower = 0, upper = ULONG_MAX;
595 union loongarch_instruction insn;
596 irqentry_state_t state = irqentry_enter(regs);
597
598 if (!pie)
599 local_irq_enable();
600
601 current->thread.trap_nr = read_csr_excode();
602
603 die_if_kernel("Bounds check error in kernel code", regs);
604
605 /*
606 * Pull out the address that failed bounds checking, and the lower /
607 * upper bound, by minimally looking at the faulting instruction word
608 * and reading from the correct register.
609 */
610 if (__get_inst(&insn.word, (u32 *)era, user))
611 goto bad_era;
612
613 switch (insn.reg3_format.opcode) {
614 case asrtle_op:
615 if (insn.reg3_format.rd != 0)
616 break; /* not asrtle */
617 badv = regs->regs[insn.reg3_format.rj];
618 upper = regs->regs[insn.reg3_format.rk];
619 break;
620
621 case asrtgt_op:
622 if (insn.reg3_format.rd != 0)
623 break; /* not asrtgt */
624 badv = regs->regs[insn.reg3_format.rj];
625 lower = regs->regs[insn.reg3_format.rk];
626 break;
627
628 case ldleb_op:
629 case ldleh_op:
630 case ldlew_op:
631 case ldled_op:
632 case stleb_op:
633 case stleh_op:
634 case stlew_op:
635 case stled_op:
636 case fldles_op:
637 case fldled_op:
638 case fstles_op:
639 case fstled_op:
640 badv = regs->regs[insn.reg3_format.rj];
641 upper = regs->regs[insn.reg3_format.rk];
642 break;
643
644 case ldgtb_op:
645 case ldgth_op:
646 case ldgtw_op:
647 case ldgtd_op:
648 case stgtb_op:
649 case stgth_op:
650 case stgtw_op:
651 case stgtd_op:
652 case fldgts_op:
653 case fldgtd_op:
654 case fstgts_op:
655 case fstgtd_op:
656 badv = regs->regs[insn.reg3_format.rj];
657 lower = regs->regs[insn.reg3_format.rk];
658 break;
659 }
660
661 force_sig_bnderr((void __user *)badv, (void __user *)lower, (void __user *)upper);
662
663 out:
664 if (!pie)
665 local_irq_disable();
666
667 irqentry_exit(regs, state);
668 return;
669
670 bad_era:
671 /*
672 * Cannot pull out the instruction word, hence cannot provide more
673 * info than a regular SIGSEGV in this case.
674 */
675 force_sig(SIGSEGV);
676 goto out;
677 }
678
do_bp(struct pt_regs * regs)679 asmlinkage void noinstr do_bp(struct pt_regs *regs)
680 {
681 bool user = user_mode(regs);
682 bool pie = regs_irqs_disabled(regs);
683 unsigned int opcode, bcode;
684 unsigned long era = exception_era(regs);
685 irqentry_state_t state = irqentry_enter(regs);
686
687 if (!pie)
688 local_irq_enable();
689
690 if (__get_inst(&opcode, (u32 *)era, user))
691 goto out_sigsegv;
692
693 bcode = (opcode & 0x7fff);
694
695 /*
696 * notify the kprobe handlers, if instruction is likely to
697 * pertain to them.
698 */
699 switch (bcode) {
700 case BRK_KDB:
701 if (kgdb_breakpoint_handler(regs))
702 goto out;
703 else
704 break;
705 case BRK_KPROBE_BP:
706 if (kprobe_breakpoint_handler(regs))
707 goto out;
708 else
709 break;
710 case BRK_KPROBE_SSTEPBP:
711 if (kprobe_singlestep_handler(regs))
712 goto out;
713 else
714 break;
715 case BRK_UPROBE_BP:
716 if (uprobe_breakpoint_handler(regs))
717 goto out;
718 else
719 break;
720 case BRK_UPROBE_XOLBP:
721 if (uprobe_singlestep_handler(regs))
722 goto out;
723 else
724 break;
725 default:
726 current->thread.trap_nr = read_csr_excode();
727 if (notify_die(DIE_TRAP, "Break", regs, bcode,
728 current->thread.trap_nr, SIGTRAP) == NOTIFY_STOP)
729 goto out;
730 else
731 break;
732 }
733
734 switch (bcode) {
735 case BRK_BUG:
736 bug_handler(regs);
737 break;
738 case BRK_DIVZERO:
739 die_if_kernel("Break instruction in kernel code", regs);
740 force_sig_fault(SIGFPE, FPE_INTDIV, (void __user *)regs->csr_era);
741 break;
742 case BRK_OVERFLOW:
743 die_if_kernel("Break instruction in kernel code", regs);
744 force_sig_fault(SIGFPE, FPE_INTOVF, (void __user *)regs->csr_era);
745 break;
746 default:
747 die_if_kernel("Break instruction in kernel code", regs);
748 force_sig_fault(SIGTRAP, TRAP_BRKPT, (void __user *)regs->csr_era);
749 break;
750 }
751
752 out:
753 if (!pie)
754 local_irq_disable();
755
756 irqentry_exit(regs, state);
757 return;
758
759 out_sigsegv:
760 force_sig(SIGSEGV);
761 goto out;
762 }
763
do_watch(struct pt_regs * regs)764 asmlinkage void noinstr do_watch(struct pt_regs *regs)
765 {
766 irqentry_state_t state = irqentry_enter(regs);
767
768 #ifndef CONFIG_HAVE_HW_BREAKPOINT
769 pr_warn("Hardware watch point handler not implemented!\n");
770 #else
771 if (kgdb_breakpoint_handler(regs))
772 goto out;
773
774 if (test_tsk_thread_flag(current, TIF_SINGLESTEP)) {
775 int llbit = (csr_read32(LOONGARCH_CSR_LLBCTL) & 0x1);
776 unsigned long pc = instruction_pointer(regs);
777 union loongarch_instruction *ip = (union loongarch_instruction *)pc;
778
779 if (llbit) {
780 /*
781 * When the ll-sc combo is encountered, it is regarded as an single
782 * instruction. So don't clear llbit and reset CSR.FWPS.Skip until
783 * the llsc execution is completed.
784 */
785 csr_write32(CSR_FWPC_SKIP, LOONGARCH_CSR_FWPS);
786 csr_write32(CSR_LLBCTL_KLO, LOONGARCH_CSR_LLBCTL);
787 goto out;
788 }
789
790 if (pc == current->thread.single_step) {
791 /*
792 * Certain insns are occasionally not skipped when CSR.FWPS.Skip is
793 * set, such as fld.d/fst.d. So singlestep needs to compare whether
794 * the csr_era is equal to the value of singlestep which last time set.
795 */
796 if (!is_self_loop_ins(ip, regs)) {
797 /*
798 * Check if the given instruction the target pc is equal to the
799 * current pc, If yes, then we should not set the CSR.FWPS.SKIP
800 * bit to break the original instruction stream.
801 */
802 csr_write32(CSR_FWPC_SKIP, LOONGARCH_CSR_FWPS);
803 goto out;
804 }
805 }
806 } else {
807 breakpoint_handler(regs);
808 watchpoint_handler(regs);
809 }
810
811 force_sig(SIGTRAP);
812 out:
813 #endif
814 irqentry_exit(regs, state);
815 }
816
do_ri(struct pt_regs * regs)817 asmlinkage void noinstr do_ri(struct pt_regs *regs)
818 {
819 int status = SIGILL;
820 unsigned int __maybe_unused opcode;
821 unsigned int __user *era = (unsigned int __user *)exception_era(regs);
822 irqentry_state_t state = irqentry_enter(regs);
823
824 local_irq_enable();
825 current->thread.trap_nr = read_csr_excode();
826
827 if (notify_die(DIE_RI, "RI Fault", regs, 0, current->thread.trap_nr,
828 SIGILL) == NOTIFY_STOP)
829 goto out;
830
831 die_if_kernel("Reserved instruction in kernel code", regs);
832
833 if (unlikely(get_user(opcode, era) < 0)) {
834 status = SIGSEGV;
835 current->thread.error_code = 1;
836 }
837
838 force_sig(status);
839
840 out:
841 local_irq_disable();
842 irqentry_exit(regs, state);
843 }
844
init_restore_fp(void)845 static void init_restore_fp(void)
846 {
847 if (!used_math()) {
848 /* First time FP context user. */
849 init_fpu();
850 } else {
851 /* This task has formerly used the FP context */
852 if (!is_fpu_owner())
853 own_fpu_inatomic(1);
854 }
855
856 BUG_ON(!is_fp_enabled());
857 }
858
init_restore_lsx(void)859 static void init_restore_lsx(void)
860 {
861 enable_lsx();
862
863 if (!thread_lsx_context_live()) {
864 /* First time LSX context user */
865 init_restore_fp();
866 init_lsx_upper();
867 set_thread_flag(TIF_LSX_CTX_LIVE);
868 } else {
869 if (!is_simd_owner()) {
870 if (is_fpu_owner()) {
871 restore_lsx_upper(current);
872 } else {
873 __own_fpu();
874 restore_lsx(current);
875 }
876 }
877 }
878
879 set_thread_flag(TIF_USEDSIMD);
880
881 BUG_ON(!is_fp_enabled());
882 BUG_ON(!is_lsx_enabled());
883 }
884
init_restore_lasx(void)885 static void init_restore_lasx(void)
886 {
887 enable_lasx();
888
889 if (!thread_lasx_context_live()) {
890 /* First time LASX context user */
891 init_restore_lsx();
892 init_lasx_upper();
893 set_thread_flag(TIF_LASX_CTX_LIVE);
894 } else {
895 if (is_fpu_owner() || is_simd_owner()) {
896 init_restore_lsx();
897 restore_lasx_upper(current);
898 } else {
899 __own_fpu();
900 enable_lsx();
901 restore_lasx(current);
902 }
903 }
904
905 set_thread_flag(TIF_USEDSIMD);
906
907 BUG_ON(!is_fp_enabled());
908 BUG_ON(!is_lsx_enabled());
909 BUG_ON(!is_lasx_enabled());
910 }
911
do_fpu(struct pt_regs * regs)912 asmlinkage void noinstr do_fpu(struct pt_regs *regs)
913 {
914 irqentry_state_t state = irqentry_enter(regs);
915
916 local_irq_enable();
917 die_if_kernel("do_fpu invoked from kernel context!", regs);
918 BUG_ON(is_lsx_enabled());
919 BUG_ON(is_lasx_enabled());
920
921 preempt_disable();
922 init_restore_fp();
923 preempt_enable();
924
925 local_irq_disable();
926 irqentry_exit(regs, state);
927 }
928
do_lsx(struct pt_regs * regs)929 asmlinkage void noinstr do_lsx(struct pt_regs *regs)
930 {
931 irqentry_state_t state = irqentry_enter(regs);
932
933 local_irq_enable();
934 if (!cpu_has_lsx) {
935 force_sig(SIGILL);
936 goto out;
937 }
938
939 die_if_kernel("do_lsx invoked from kernel context!", regs);
940 BUG_ON(is_lasx_enabled());
941
942 preempt_disable();
943 init_restore_lsx();
944 preempt_enable();
945
946 out:
947 local_irq_disable();
948 irqentry_exit(regs, state);
949 }
950
do_lasx(struct pt_regs * regs)951 asmlinkage void noinstr do_lasx(struct pt_regs *regs)
952 {
953 irqentry_state_t state = irqentry_enter(regs);
954
955 local_irq_enable();
956 if (!cpu_has_lasx) {
957 force_sig(SIGILL);
958 goto out;
959 }
960
961 die_if_kernel("do_lasx invoked from kernel context!", regs);
962
963 preempt_disable();
964 init_restore_lasx();
965 preempt_enable();
966
967 out:
968 local_irq_disable();
969 irqentry_exit(regs, state);
970 }
971
init_restore_lbt(void)972 static void init_restore_lbt(void)
973 {
974 if (!thread_lbt_context_live()) {
975 /* First time LBT context user */
976 init_lbt();
977 set_thread_flag(TIF_LBT_CTX_LIVE);
978 } else {
979 if (!is_lbt_owner())
980 own_lbt_inatomic(1);
981 }
982
983 BUG_ON(!is_lbt_enabled());
984 }
985
do_lbt(struct pt_regs * regs)986 asmlinkage void noinstr do_lbt(struct pt_regs *regs)
987 {
988 bool pie = regs_irqs_disabled(regs);
989 irqentry_state_t state = irqentry_enter(regs);
990
991 /*
992 * BTD (Binary Translation Disable exception) can be triggered
993 * during FP save/restore if TM (Top Mode) is on, which may
994 * cause irq_enable during 'switch_to'. To avoid this situation
995 * (including the user using 'MOVGR2GCSR' to turn on TM, which
996 * will not trigger the BTE), we need to check PRMD first.
997 */
998 if (!pie)
999 local_irq_enable();
1000
1001 if (!cpu_has_lbt) {
1002 force_sig(SIGILL);
1003 goto out;
1004 }
1005 BUG_ON(is_lbt_enabled());
1006
1007 preempt_disable();
1008 init_restore_lbt();
1009 preempt_enable();
1010
1011 out:
1012 if (!pie)
1013 local_irq_disable();
1014
1015 irqentry_exit(regs, state);
1016 }
1017
do_reserved(struct pt_regs * regs)1018 asmlinkage void noinstr do_reserved(struct pt_regs *regs)
1019 {
1020 irqentry_state_t state = irqentry_enter(regs);
1021
1022 local_irq_enable();
1023 /*
1024 * Game over - no way to handle this if it ever occurs. Most probably
1025 * caused by a fatal error after another hardware/software error.
1026 */
1027 pr_err("Caught reserved exception %u on pid:%d [%s] - should not happen\n",
1028 read_csr_excode(), current->pid, current->comm);
1029 die_if_kernel("do_reserved exception", regs);
1030 force_sig(SIGUNUSED);
1031
1032 local_irq_disable();
1033
1034 irqentry_exit(regs, state);
1035 }
1036
cache_parity_error(void)1037 asmlinkage void cache_parity_error(void)
1038 {
1039 /* For the moment, report the problem and hang. */
1040 pr_err("Cache error exception:\n");
1041 pr_err("csr_merrctl == %08x\n", csr_read32(LOONGARCH_CSR_MERRCTL));
1042 pr_err("csr_merrera == %016lx\n", csr_read64(LOONGARCH_CSR_MERRERA));
1043 panic("Can't handle the cache error!");
1044 }
1045
handle_loongarch_irq(struct pt_regs * regs)1046 asmlinkage void noinstr handle_loongarch_irq(struct pt_regs *regs)
1047 {
1048 struct pt_regs *old_regs;
1049
1050 irq_enter_rcu();
1051 old_regs = set_irq_regs(regs);
1052 handle_arch_irq(regs);
1053 set_irq_regs(old_regs);
1054 irq_exit_rcu();
1055 }
1056
do_vint(struct pt_regs * regs,unsigned long sp)1057 asmlinkage void noinstr do_vint(struct pt_regs *regs, unsigned long sp)
1058 {
1059 register int cpu;
1060 register unsigned long stack;
1061 irqentry_state_t state = irqentry_enter(regs);
1062
1063 cpu = smp_processor_id();
1064
1065 if (on_irq_stack(cpu, sp))
1066 handle_loongarch_irq(regs);
1067 else {
1068 stack = per_cpu(irq_stack, cpu) + IRQ_STACK_START;
1069
1070 /* Save task's sp on IRQ stack for unwinding */
1071 *(unsigned long *)stack = sp;
1072
1073 __asm__ __volatile__(
1074 "move $s0, $sp \n" /* Preserve sp */
1075 "move $sp, %[stk] \n" /* Switch stack */
1076 "move $a0, %[regs] \n"
1077 "bl handle_loongarch_irq \n"
1078 "move $sp, $s0 \n" /* Restore sp */
1079 : /* No outputs */
1080 : [stk] "r" (stack), [regs] "r" (regs)
1081 : "$a0", "$a1", "$a2", "$a3", "$a4", "$a5", "$a6", "$a7", "$s0",
1082 "$t0", "$t1", "$t2", "$t3", "$t4", "$t5", "$t6", "$t7", "$t8",
1083 "memory");
1084 }
1085
1086 irqentry_exit(regs, state);
1087 }
1088
1089 unsigned long eentry;
1090 unsigned long tlbrentry;
1091
1092 long exception_handlers[VECSIZE * 128 / sizeof(long)] __aligned(SZ_64K);
1093
configure_exception_vector(void)1094 static void configure_exception_vector(void)
1095 {
1096 eentry = (unsigned long)exception_handlers;
1097 tlbrentry = (unsigned long)exception_handlers + 80*VECSIZE;
1098
1099 csr_write64(eentry, LOONGARCH_CSR_EENTRY);
1100 csr_write64(eentry, LOONGARCH_CSR_MERRENTRY);
1101 csr_write64(tlbrentry, LOONGARCH_CSR_TLBRENTRY);
1102 }
1103
per_cpu_trap_init(int cpu)1104 void per_cpu_trap_init(int cpu)
1105 {
1106 unsigned int i;
1107
1108 setup_vint_size(VECSIZE);
1109
1110 configure_exception_vector();
1111
1112 if (!cpu_data[cpu].asid_cache)
1113 cpu_data[cpu].asid_cache = asid_first_version(cpu);
1114
1115 mmgrab(&init_mm);
1116 current->active_mm = &init_mm;
1117 BUG_ON(current->mm);
1118 enter_lazy_tlb(&init_mm, current);
1119
1120 /* Initialise exception handlers */
1121 if (cpu == 0)
1122 for (i = 0; i < 64; i++)
1123 set_handler(i * VECSIZE, handle_reserved, VECSIZE);
1124
1125 tlb_init(cpu);
1126 cpu_cache_init();
1127 }
1128
1129 /* Install CPU exception handler */
set_handler(unsigned long offset,void * addr,unsigned long size)1130 void set_handler(unsigned long offset, void *addr, unsigned long size)
1131 {
1132 memcpy((void *)(eentry + offset), addr, size);
1133 local_flush_icache_range(eentry + offset, eentry + offset + size);
1134 }
1135
1136 static const char panic_null_cerr[] =
1137 "Trying to set NULL cache error exception handler\n";
1138
1139 /*
1140 * Install uncached CPU exception handler.
1141 * This is suitable only for the cache error exception which is the only
1142 * exception handler that is being run uncached.
1143 */
set_merr_handler(unsigned long offset,void * addr,unsigned long size)1144 void set_merr_handler(unsigned long offset, void *addr, unsigned long size)
1145 {
1146 unsigned long uncached_eentry = TO_UNCACHE(__pa(eentry));
1147
1148 if (!addr)
1149 panic(panic_null_cerr);
1150
1151 memcpy((void *)(uncached_eentry + offset), addr, size);
1152 }
1153
trap_init(void)1154 void __init trap_init(void)
1155 {
1156 long i;
1157
1158 /* Set interrupt vector handler */
1159 for (i = EXCCODE_INT_START; i <= EXCCODE_INT_END; i++)
1160 set_handler(i * VECSIZE, handle_vint, VECSIZE);
1161
1162 set_handler(EXCCODE_ADE * VECSIZE, handle_ade, VECSIZE);
1163 set_handler(EXCCODE_ALE * VECSIZE, handle_ale, VECSIZE);
1164 set_handler(EXCCODE_BCE * VECSIZE, handle_bce, VECSIZE);
1165 set_handler(EXCCODE_SYS * VECSIZE, handle_sys, VECSIZE);
1166 set_handler(EXCCODE_BP * VECSIZE, handle_bp, VECSIZE);
1167 set_handler(EXCCODE_INE * VECSIZE, handle_ri, VECSIZE);
1168 set_handler(EXCCODE_IPE * VECSIZE, handle_ri, VECSIZE);
1169 set_handler(EXCCODE_FPDIS * VECSIZE, handle_fpu, VECSIZE);
1170 set_handler(EXCCODE_LSXDIS * VECSIZE, handle_lsx, VECSIZE);
1171 set_handler(EXCCODE_LASXDIS * VECSIZE, handle_lasx, VECSIZE);
1172 set_handler(EXCCODE_FPE * VECSIZE, handle_fpe, VECSIZE);
1173 set_handler(EXCCODE_BTDIS * VECSIZE, handle_lbt, VECSIZE);
1174 set_handler(EXCCODE_WATCH * VECSIZE, handle_watch, VECSIZE);
1175
1176 cache_error_setup();
1177
1178 local_flush_icache_range(eentry, eentry + 0x400);
1179 }
1180