2 * arch/xtensa/kernel/traps.c
6 * Derived from code with the following copyrights:
7 * Copyright (C) 1994 - 1999 by Ralf Baechle
8 * Modified for R3000 by Paul M. Antoine, 1995, 1996
9 * Complete output from die() by Ulf Carlsson, 1998
10 * Copyright (C) 1999 Silicon Graphics, Inc.
12 * Essentially rewritten for the Xtensa architecture port.
14 * Copyright (C) 2001 - 2013 Tensilica Inc.
16 * Joe Taylor <joe@tensilica.com, joetylr@yahoo.com>
17 * Chris Zankel <chris@zankel.net>
18 * Marc Gauthier<marc@tensilica.com, marc@alumni.uwaterloo.ca>
21 * This file is subject to the terms and conditions of the GNU General Public
22 * License. See the file "COPYING" in the main directory of this archive
26 #include <linux/kernel.h>
27 #include <linux/sched/signal.h>
28 #include <linux/sched/debug.h>
29 #include <linux/sched/task_stack.h>
30 #include <linux/init.h>
31 #include <linux/module.h>
32 #include <linux/stringify.h>
33 #include <linux/kallsyms.h>
34 #include <linux/delay.h>
35 #include <linux/hardirq.h>
36 #include <linux/ratelimit.h>
37 #include <linux/pgtable.h>
39 #include <asm/stacktrace.h>
40 #include <asm/ptrace.h>
41 #include <asm/timex.h>
42 #include <linux/uaccess.h>
43 #include <asm/processor.h>
44 #include <asm/traps.h>
45 #include <asm/hw_breakpoint.h>
48 * Machine specific interrupt handlers
51 static void do_illegal_instruction(struct pt_regs *regs);
52 static void do_div0(struct pt_regs *regs);
53 static void do_interrupt(struct pt_regs *regs);
55 static void do_nmi(struct pt_regs *regs);
57 #ifdef CONFIG_XTENSA_LOAD_STORE
58 static void do_load_store(struct pt_regs *regs);
60 static void do_unaligned_user(struct pt_regs *regs);
61 static void do_multihit(struct pt_regs *regs);
62 #if XTENSA_HAVE_COPROCESSORS
63 static void do_coprocessor(struct pt_regs *regs);
65 static void do_debug(struct pt_regs *regs);
68 * The vector table must be preceded by a save area (which
69 * implies it must be in RAM, unless one places RAM immediately
70 * before a ROM and puts the vector at the start of the ROM (!))
76 #define COPROCESSOR(x) \
77 { EXCCAUSE_COPROCESSOR ## x ## _DISABLED, USER|KRNL, fast_coprocessor },\
78 { EXCCAUSE_COPROCESSOR ## x ## _DISABLED, 0, do_coprocessor }
84 } dispatch_init_table_t;
86 static dispatch_init_table_t __initdata dispatch_init_table[] = {
88 #ifdef CONFIG_USER_ABI_CALL0_PROBE
89 { EXCCAUSE_ILLEGAL_INSTRUCTION, USER, fast_illegal_instruction_user },
91 { EXCCAUSE_ILLEGAL_INSTRUCTION, 0, do_illegal_instruction},
92 { EXCCAUSE_SYSTEM_CALL, USER, fast_syscall_user },
93 { EXCCAUSE_SYSTEM_CALL, 0, system_call },
94 /* EXCCAUSE_INSTRUCTION_FETCH unhandled */
95 #ifdef CONFIG_XTENSA_LOAD_STORE
96 { EXCCAUSE_LOAD_STORE_ERROR, USER|KRNL, fast_load_store },
97 { EXCCAUSE_LOAD_STORE_ERROR, 0, do_load_store },
99 { EXCCAUSE_LEVEL1_INTERRUPT, 0, do_interrupt },
100 #ifdef SUPPORT_WINDOWED
101 { EXCCAUSE_ALLOCA, USER|KRNL, fast_alloca },
103 { EXCCAUSE_INTEGER_DIVIDE_BY_ZERO, 0, do_div0 },
104 /* EXCCAUSE_PRIVILEGED unhandled */
105 #if XCHAL_UNALIGNED_LOAD_EXCEPTION || XCHAL_UNALIGNED_STORE_EXCEPTION || \
106 IS_ENABLED(CONFIG_XTENSA_LOAD_STORE)
107 #ifdef CONFIG_XTENSA_UNALIGNED_USER
108 { EXCCAUSE_UNALIGNED, USER, fast_unaligned },
110 { EXCCAUSE_UNALIGNED, KRNL, fast_unaligned },
112 { EXCCAUSE_UNALIGNED, 0, do_unaligned_user },
114 { EXCCAUSE_ITLB_MISS, 0, do_page_fault },
115 { EXCCAUSE_ITLB_MISS, USER|KRNL, fast_second_level_miss},
116 { EXCCAUSE_DTLB_MISS, USER|KRNL, fast_second_level_miss},
117 { EXCCAUSE_DTLB_MISS, 0, do_page_fault },
118 { EXCCAUSE_STORE_CACHE_ATTRIBUTE, USER|KRNL, fast_store_prohibited },
119 #endif /* CONFIG_MMU */
121 { EXCCAUSE_ITLB_MULTIHIT, 0, do_multihit },
122 { EXCCAUSE_ITLB_PRIVILEGE, 0, do_page_fault },
123 { EXCCAUSE_FETCH_CACHE_ATTRIBUTE, 0, do_page_fault },
124 { EXCCAUSE_DTLB_MULTIHIT, 0, do_multihit },
125 { EXCCAUSE_DTLB_PRIVILEGE, 0, do_page_fault },
126 { EXCCAUSE_STORE_CACHE_ATTRIBUTE, 0, do_page_fault },
127 { EXCCAUSE_LOAD_CACHE_ATTRIBUTE, 0, do_page_fault },
129 /* XCCHAL_EXCCAUSE_FLOATING_POINT unhandled */
130 #if XTENSA_HAVE_COPROCESSOR(0)
133 #if XTENSA_HAVE_COPROCESSOR(1)
136 #if XTENSA_HAVE_COPROCESSOR(2)
139 #if XTENSA_HAVE_COPROCESSOR(3)
142 #if XTENSA_HAVE_COPROCESSOR(4)
145 #if XTENSA_HAVE_COPROCESSOR(5)
148 #if XTENSA_HAVE_COPROCESSOR(6)
151 #if XTENSA_HAVE_COPROCESSOR(7)
155 { EXCCAUSE_MAPPED_NMI, 0, do_nmi },
157 { EXCCAUSE_MAPPED_DEBUG, 0, do_debug },
162 /* The exception table <exc_table> serves two functions:
163 * 1. it contains three dispatch tables (fast_user, fast_kernel, default-c)
164 * 2. it is a temporary memory buffer for the exception handlers.
167 DEFINE_PER_CPU(struct exc_table, exc_table);
168 DEFINE_PER_CPU(struct debug_table, debug_table);
170 void die(const char*, struct pt_regs*, long);
173 __die_if_kernel(const char *str, struct pt_regs *regs, long err)
175 if (!user_mode(regs))
179 #ifdef CONFIG_PRINT_USER_CODE_ON_UNHANDLED_EXCEPTION
180 static inline void dump_user_code(struct pt_regs *regs)
184 if (copy_from_user(buf, (void __user *)(regs->pc & -16), sizeof(buf)) == 0) {
185 print_hex_dump(KERN_INFO, " ", DUMP_PREFIX_NONE,
186 32, 1, buf, sizeof(buf), false);
191 static inline void dump_user_code(struct pt_regs *regs)
197 * Unhandled Exceptions. Kill user task or panic if in kernel space.
200 void do_unhandled(struct pt_regs *regs)
202 __die_if_kernel("Caught unhandled exception - should not happen",
205 /* If in user mode, send SIGILL signal to current process */
206 pr_info_ratelimited("Caught unhandled exception in '%s' "
207 "(pid = %d, pc = %#010lx) - should not happen\n"
208 "\tEXCCAUSE is %ld\n",
209 current->comm, task_pid_nr(current), regs->pc,
211 dump_user_code(regs);
216 * Multi-hit exception. This if fatal!
219 static void do_multihit(struct pt_regs *regs)
221 die("Caught multihit exception", regs, SIGKILL);
230 #define IS_POW2(v) (((v) & ((v) - 1)) == 0)
232 #if !(PROFILING_INTLEVEL == XCHAL_EXCM_LEVEL && \
233 IS_POW2(XTENSA_INTLEVEL_MASK(PROFILING_INTLEVEL)))
234 #warning "Fake NMI is requested for PMM, but there are other IRQs at or above its level."
235 #warning "Fake NMI will be used, but there will be a bugcheck if one of those IRQs fire."
237 static inline void check_valid_nmi(void)
239 unsigned intread = xtensa_get_sr(interrupt);
240 unsigned intenable = xtensa_get_sr(intenable);
242 BUG_ON(intread & intenable &
243 ~(XTENSA_INTLEVEL_ANDBELOW_MASK(PROFILING_INTLEVEL) ^
244 XTENSA_INTLEVEL_MASK(PROFILING_INTLEVEL) ^
245 BIT(XCHAL_PROFILING_INTERRUPT)));
250 static inline void check_valid_nmi(void)
256 irqreturn_t xtensa_pmu_irq_handler(int irq, void *dev_id);
258 DEFINE_PER_CPU(unsigned long, nmi_count);
260 static void do_nmi(struct pt_regs *regs)
262 struct pt_regs *old_regs = set_irq_regs(regs);
265 ++*this_cpu_ptr(&nmi_count);
267 xtensa_pmu_irq_handler(0, NULL);
269 set_irq_regs(old_regs);
273 static void do_interrupt(struct pt_regs *regs)
275 static const unsigned int_level_mask[] = {
277 XCHAL_INTLEVEL1_MASK,
278 XCHAL_INTLEVEL2_MASK,
279 XCHAL_INTLEVEL3_MASK,
280 XCHAL_INTLEVEL4_MASK,
281 XCHAL_INTLEVEL5_MASK,
282 XCHAL_INTLEVEL6_MASK,
283 XCHAL_INTLEVEL7_MASK,
285 struct pt_regs *old_regs = set_irq_regs(regs);
286 unsigned unhandled = ~0u;
291 unsigned intread = xtensa_get_sr(interrupt);
292 unsigned intenable = xtensa_get_sr(intenable);
293 unsigned int_at_level = intread & intenable;
296 for (level = LOCKLEVEL; level > 0; --level) {
297 if (int_at_level & int_level_mask[level]) {
298 int_at_level &= int_level_mask[level];
299 if (int_at_level & unhandled)
300 int_at_level &= unhandled;
302 unhandled |= int_level_mask[level];
310 /* clear lowest pending irq in the unhandled mask */
311 unhandled ^= (int_at_level & -int_at_level);
312 do_IRQ(__ffs(int_at_level), regs);
316 set_irq_regs(old_regs);
319 static bool check_div0(struct pt_regs *regs)
321 static const u8 pattern[] = {'D', 'I', 'V', '0'};
325 if (user_mode(regs)) {
326 if (copy_from_user(buf, (void __user *)regs->pc + 2, 5))
330 p = (const u8 *)regs->pc + 2;
333 return memcmp(p, pattern, sizeof(pattern)) == 0 ||
334 memcmp(p + 1, pattern, sizeof(pattern)) == 0;
338 * Illegal instruction. Fatal if in kernel space.
341 static void do_illegal_instruction(struct pt_regs *regs)
343 #ifdef CONFIG_USER_ABI_CALL0_PROBE
345 * When call0 application encounters an illegal instruction fast
346 * exception handler will attempt to set PS.WOE and retry failing
348 * If we get here we know that that instruction is also illegal
349 * with PS.WOE set, so it's not related to the windowed option
350 * hence PS.WOE may be cleared.
352 if (regs->pc == current_thread_info()->ps_woe_fix_addr)
353 regs->ps &= ~PS_WOE_MASK;
355 if (check_div0(regs)) {
360 __die_if_kernel("Illegal instruction in kernel", regs, SIGKILL);
362 /* If in user mode, send SIGILL signal to current process. */
364 pr_info_ratelimited("Illegal Instruction in '%s' (pid = %d, pc = %#010lx)\n",
365 current->comm, task_pid_nr(current), regs->pc);
369 static void do_div0(struct pt_regs *regs)
371 __die_if_kernel("Unhandled division by 0 in kernel", regs, SIGKILL);
372 force_sig_fault(SIGFPE, FPE_INTDIV, (void __user *)regs->pc);
375 #ifdef CONFIG_XTENSA_LOAD_STORE
376 static void do_load_store(struct pt_regs *regs)
378 __die_if_kernel("Unhandled load/store exception in kernel",
381 pr_info_ratelimited("Load/store error to %08lx in '%s' (pid = %d, pc = %#010lx)\n",
382 regs->excvaddr, current->comm,
383 task_pid_nr(current), regs->pc);
384 force_sig_fault(SIGBUS, BUS_ADRERR, (void *)regs->excvaddr);
389 * Handle unaligned memory accesses from user space. Kill task.
391 * If CONFIG_UNALIGNED_USER is not set, we don't allow unaligned memory
392 * accesses causes from user space.
395 static void do_unaligned_user(struct pt_regs *regs)
397 __die_if_kernel("Unhandled unaligned exception in kernel",
400 pr_info_ratelimited("Unaligned memory access to %08lx in '%s' "
401 "(pid = %d, pc = %#010lx)\n",
402 regs->excvaddr, current->comm,
403 task_pid_nr(current), regs->pc);
404 force_sig_fault(SIGBUS, BUS_ADRALN, (void *) regs->excvaddr);
407 #if XTENSA_HAVE_COPROCESSORS
408 static void do_coprocessor(struct pt_regs *regs)
410 coprocessor_flush_release_all(current_thread_info());
414 /* Handle debug events.
415 * When CONFIG_HAVE_HW_BREAKPOINT is on this handler is called with
416 * preemption disabled to avoid rescheduling and keep mapping of hardware
417 * breakpoint structures to debug registers intact, so that
418 * DEBUGCAUSE.DBNUM could be used in case of data breakpoint hit.
420 static void do_debug(struct pt_regs *regs)
422 #ifdef CONFIG_HAVE_HW_BREAKPOINT
423 int ret = check_hw_breakpoint(regs);
429 __die_if_kernel("Breakpoint in kernel", regs, SIGKILL);
431 /* If in user mode, send SIGTRAP signal to current process */
437 #define set_handler(type, cause, handler) \
441 for_each_possible_cpu(cpu) \
442 per_cpu(exc_table, cpu).type[cause] = (handler);\
445 /* Set exception C handler - for temporary use when probing exceptions */
447 xtensa_exception_handler *
448 __init trap_set_handler(int cause, xtensa_exception_handler *handler)
450 void *previous = per_cpu(exc_table, 0).default_handler[cause];
452 set_handler(default_handler, cause, handler);
457 static void trap_init_excsave(void)
459 xtensa_set_sr(this_cpu_ptr(&exc_table), excsave1);
462 static void trap_init_debug(void)
464 unsigned long debugsave = (unsigned long)this_cpu_ptr(&debug_table);
466 this_cpu_ptr(&debug_table)->debug_exception = debug_exception;
467 __asm__ __volatile__("wsr %0, excsave" __stringify(XCHAL_DEBUGLEVEL)
472 * Initialize dispatch tables.
474 * The exception vectors are stored compressed the __init section in the
475 * dispatch_init_table. This function initializes the following three tables
476 * from that compressed table:
477 * - fast user first dispatch table for user exceptions
478 * - fast kernel first dispatch table for kernel exceptions
479 * - default C-handler C-handler called by the default fast handler.
481 * See vectors.S for more details.
484 void __init trap_init(void)
488 /* Setup default vectors. */
490 for (i = 0; i < EXCCAUSE_N; i++) {
491 set_handler(fast_user_handler, i, user_exception);
492 set_handler(fast_kernel_handler, i, kernel_exception);
493 set_handler(default_handler, i, do_unhandled);
496 /* Setup specific handlers. */
498 for(i = 0; dispatch_init_table[i].cause >= 0; i++) {
499 int fast = dispatch_init_table[i].fast;
500 int cause = dispatch_init_table[i].cause;
501 void *handler = dispatch_init_table[i].handler;
504 set_handler(default_handler, cause, handler);
505 if ((fast & USER) != 0)
506 set_handler(fast_user_handler, cause, handler);
507 if ((fast & KRNL) != 0)
508 set_handler(fast_kernel_handler, cause, handler);
511 /* Initialize EXCSAVE_1 to hold the address of the exception table. */
517 void secondary_trap_init(void)
525 * This function dumps the current valid window frame and other base registers.
528 void show_regs(struct pt_regs * regs)
532 show_regs_print_info(KERN_DEFAULT);
534 for (i = 0; i < 16; i++) {
536 pr_info("a%02d:", i);
537 pr_cont(" %08lx", regs->areg[i]);
540 pr_info("pc: %08lx, ps: %08lx, depc: %08lx, excvaddr: %08lx\n",
541 regs->pc, regs->ps, regs->depc, regs->excvaddr);
542 pr_info("lbeg: %08lx, lend: %08lx lcount: %08lx, sar: %08lx\n",
543 regs->lbeg, regs->lend, regs->lcount, regs->sar);
545 pr_cont("wb: %08lx, ws: %08lx, wmask: %08lx, syscall: %ld\n",
546 regs->windowbase, regs->windowstart, regs->wmask,
550 static int show_trace_cb(struct stackframe *frame, void *data)
552 const char *loglvl = data;
554 if (kernel_text_address(frame->pc))
555 printk("%s [<%08lx>] %pB\n",
556 loglvl, frame->pc, (void *)frame->pc);
560 static void show_trace(struct task_struct *task, unsigned long *sp,
564 sp = stack_pointer(task);
566 printk("%sCall Trace:\n", loglvl);
567 walk_stackframe(sp, show_trace_cb, (void *)loglvl);
570 #define STACK_DUMP_ENTRY_SIZE 4
571 #define STACK_DUMP_LINE_SIZE 16
572 static size_t kstack_depth_to_print = CONFIG_PRINT_STACK_DEPTH;
574 struct stack_fragment
582 static int show_stack_fragment_cb(struct stackframe *frame, void *data)
584 struct stack_fragment *sf = data;
586 while (sf->off < sf->len) {
587 u8 line[STACK_DUMP_LINE_SIZE];
588 size_t line_len = sf->len - sf->off > STACK_DUMP_LINE_SIZE ?
589 STACK_DUMP_LINE_SIZE : sf->len - sf->off;
590 bool arrow = sf->off == 0;
592 if (frame && frame->sp == (unsigned long)(sf->sp + sf->off))
595 __memcpy(line, sf->sp + sf->off, line_len);
596 print_hex_dump(sf->loglvl, arrow ? "> " : " ", DUMP_PREFIX_NONE,
597 STACK_DUMP_LINE_SIZE, STACK_DUMP_ENTRY_SIZE,
598 line, line_len, false);
599 sf->off += STACK_DUMP_LINE_SIZE;
606 void show_stack(struct task_struct *task, unsigned long *sp, const char *loglvl)
608 struct stack_fragment sf;
611 sp = stack_pointer(task);
613 sf.len = min((-(size_t)sp) & (THREAD_SIZE - STACK_DUMP_ENTRY_SIZE),
614 kstack_depth_to_print * STACK_DUMP_ENTRY_SIZE);
619 printk("%sStack:\n", loglvl);
620 walk_stackframe(sp, show_stack_fragment_cb, &sf);
621 while (sf.off < sf.len)
622 show_stack_fragment_cb(NULL, &sf);
623 show_trace(task, sp, loglvl);
626 DEFINE_SPINLOCK(die_lock);
628 void __noreturn die(const char * str, struct pt_regs * regs, long err)
630 static int die_counter;
633 if (IS_ENABLED(CONFIG_PREEMPTION))
634 pr = IS_ENABLED(CONFIG_PREEMPT_RT) ? " PREEMPT_RT" : " PREEMPT";
637 spin_lock_irq(&die_lock);
639 pr_info("%s: sig: %ld [#%d]%s\n", str, err, ++die_counter, pr);
641 if (!user_mode(regs))
642 show_stack(NULL, (unsigned long *)regs->areg[1], KERN_INFO);
644 add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
645 spin_unlock_irq(&die_lock);
648 panic("Fatal exception in interrupt");
651 panic("Fatal exception");