arch/riscv/kernel/traps.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (C) 2012 Regents of the University of California
   4  */
   5
   6 #include <linux/cpu.h>
   7 #include <linux/kernel.h>
   8 #include <linux/init.h>
   9 #include <linux/sched.h>
  10 #include <linux/sched/debug.h>
  11 #include <linux/sched/signal.h>
  12 #include <linux/signal.h>
  13 #include <linux/kdebug.h>
  14 #include <linux/uaccess.h>
  15 #include <linux/mm.h>
  16 #include <linux/module.h>
  17 #include <linux/irq.h>
  18
  19 #include <asm/processor.h>
  20 #include <asm/ptrace.h>
  21 #include <asm/csr.h>
  22
  23 int show_unhandled_signals = 1;
  24
  25 extern asmlinkage void handle_exception(void);
  26
  27 static DEFINE_SPINLOCK(die_lock);
  28
  29 void die(struct pt_regs *regs, const char *str)
  30 {
  31         static int die_counter;
  32         int ret;
  33
  34         oops_enter();
  35
  36         spin_lock_irq(&die_lock);
  37         console_verbose();
  38         bust_spinlocks(1);
  39
  40         pr_emerg("%s [#%d]\n", str, ++die_counter);
  41         print_modules();
  42         show_regs(regs);
  43
  44         ret = notify_die(DIE_OOPS, str, regs, 0, regs->cause, SIGSEGV);
  45
  46         bust_spinlocks(0);
  47         add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
  48         spin_unlock_irq(&die_lock);
  49         oops_exit();
  50
  51         if (in_interrupt())
  52                 panic("Fatal exception in interrupt");
  53         if (panic_on_oops)
  54                 panic("Fatal exception");
  55         if (ret != NOTIFY_STOP)
  56                 do_exit(SIGSEGV);
  57 }
  58
  59 void do_trap(struct pt_regs *regs, int signo, int code, unsigned long addr)
  60 {
  61         struct task_struct *tsk = current;
  62
  63         if (show_unhandled_signals && unhandled_signal(tsk, signo)
  64             && printk_ratelimit()) {
  65                 pr_info("%s[%d]: unhandled signal %d code 0x%x at 0x" REG_FMT,
  66                         tsk->comm, task_pid_nr(tsk), signo, code, addr);
  67                 print_vma_addr(KERN_CONT " in ", instruction_pointer(regs));
  68                 pr_cont("\n");
  69                 show_regs(regs);
  70         }
  71
  72         force_sig_fault(signo, code, (void __user *)addr);
  73 }
  74
  75 static void do_trap_error(struct pt_regs *regs, int signo, int code,
  76         unsigned long addr, const char *str)
  77 {
  78         if (user_mode(regs)) {
  79                 do_trap(regs, signo, code, addr);
  80         } else {
  81                 if (!fixup_exception(regs))
  82                         die(regs, str);
  83         }
  84 }
  85
  86 #define DO_ERROR_INFO(name, signo, code, str)                           \
  87 asmlinkage __visible void name(struct pt_regs *regs)                    \
  88 {                                                                       \
  89         do_trap_error(regs, signo, code, regs->epc, "Oops - " str);     \
  90 }
  91
  92 DO_ERROR_INFO(do_trap_unknown,
  93         SIGILL, ILL_ILLTRP, "unknown exception");
  94 DO_ERROR_INFO(do_trap_insn_misaligned,
  95         SIGBUS, BUS_ADRALN, "instruction address misaligned");
  96 DO_ERROR_INFO(do_trap_insn_fault,
  97         SIGSEGV, SEGV_ACCERR, "instruction access fault");
  98 DO_ERROR_INFO(do_trap_insn_illegal,
  99         SIGILL, ILL_ILLOPC, "illegal instruction");
 100 DO_ERROR_INFO(do_trap_load_fault,
 101         SIGSEGV, SEGV_ACCERR, "load access fault");
 102 #ifndef CONFIG_RISCV_M_MODE
 103 DO_ERROR_INFO(do_trap_load_misaligned,
 104         SIGBUS, BUS_ADRALN, "Oops - load address misaligned");
 105 DO_ERROR_INFO(do_trap_store_misaligned,
 106         SIGBUS, BUS_ADRALN, "Oops - store (or AMO) address misaligned");
 107 #else
 108 int handle_misaligned_load(struct pt_regs *regs);
 109 int handle_misaligned_store(struct pt_regs *regs);
 110
 111 asmlinkage void do_trap_load_misaligned(struct pt_regs *regs)
 112 {
 113         if (!handle_misaligned_load(regs))
 114                 return;
 115         do_trap_error(regs, SIGBUS, BUS_ADRALN, regs->epc,
 116                       "Oops - load address misaligned");
 117 }
 118
 119 asmlinkage void do_trap_store_misaligned(struct pt_regs *regs)
 120 {
 121         if (!handle_misaligned_store(regs))
 122                 return;
 123         do_trap_error(regs, SIGBUS, BUS_ADRALN, regs->epc,
 124                       "Oops - store (or AMO) address misaligned");
 125 }
 126 #endif
 127 DO_ERROR_INFO(do_trap_store_fault,
 128         SIGSEGV, SEGV_ACCERR, "store (or AMO) access fault");
 129 DO_ERROR_INFO(do_trap_ecall_u,
 130         SIGILL, ILL_ILLTRP, "environment call from U-mode");
 131 DO_ERROR_INFO(do_trap_ecall_s,
 132         SIGILL, ILL_ILLTRP, "environment call from S-mode");
 133 DO_ERROR_INFO(do_trap_ecall_m,
 134         SIGILL, ILL_ILLTRP, "environment call from M-mode");
 135
 136 static inline unsigned long get_break_insn_length(unsigned long pc)
 137 {
 138         bug_insn_t insn;
 139
 140         if (get_kernel_nofault(insn, (bug_insn_t *)pc))
 141                 return 0;
 142
 143         return GET_INSN_LENGTH(insn);
 144 }
 145
 146 asmlinkage __visible void do_trap_break(struct pt_regs *regs)
 147 {
 148         if (user_mode(regs))
 149                 force_sig_fault(SIGTRAP, TRAP_BRKPT, (void __user *)regs->epc);
 150 #ifdef CONFIG_KGDB
 151         else if (notify_die(DIE_TRAP, "EBREAK", regs, 0, regs->cause, SIGTRAP)
 152                                                                 == NOTIFY_STOP)
 153                 return;
 154 #endif
 155         else if (report_bug(regs->epc, regs) == BUG_TRAP_TYPE_WARN)
 156                 regs->epc += get_break_insn_length(regs->epc);
 157         else
 158                 die(regs, "Kernel BUG");
 159 }
 160
 161 #ifdef CONFIG_GENERIC_BUG
 162 int is_valid_bugaddr(unsigned long pc)
 163 {
 164         bug_insn_t insn;
 165
 166         if (pc < VMALLOC_START)
 167                 return 0;
 168         if (get_kernel_nofault(insn, (bug_insn_t *)pc))
 169                 return 0;
 170         if ((insn & __INSN_LENGTH_MASK) == __INSN_LENGTH_32)
 171                 return (insn == __BUG_INSN_32);
 172         else
 173                 return ((insn & __COMPRESSED_INSN_MASK) == __BUG_INSN_16);
 174 }
 175 #endif /* CONFIG_GENERIC_BUG */
 176
 177 /* stvec & scratch is already set from head.S */
 178 void trap_init(void)
 179 {
 180 }