arch/riscv/kernel/traps.c

   1 /*
   2  * Copyright (C) 2012 Regents of the University of California
   3  *
   4  *   This program is free software; you can redistribute it and/or
   5  *   modify it under the terms of the GNU General Public License
   6  *   as published by the Free Software Foundation, version 2.
   7  *
   8  *   This program is distributed in the hope that it will be useful,
   9  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  *   GNU General Public License for more details.
  12  */
  13
  14 #include <linux/kernel.h>
  15 #include <linux/init.h>
  16 #include <linux/sched.h>
  17 #include <linux/sched/debug.h>
  18 #include <linux/sched/signal.h>
  19 #include <linux/signal.h>
  20 #include <linux/kdebug.h>
  21 #include <linux/uaccess.h>
  22 #include <linux/mm.h>
  23 #include <linux/module.h>
  24 #include <linux/irq.h>
  25
  26 #include <asm/processor.h>
  27 #include <asm/ptrace.h>
  28 #include <asm/csr.h>
  29
  30 int show_unhandled_signals = 1;
  31
  32 extern asmlinkage void handle_exception(void);
  33
  34 static DEFINE_SPINLOCK(die_lock);
  35
  36 void die(struct pt_regs *regs, const char *str)
  37 {
  38         static int die_counter;
  39         int ret;
  40
  41         oops_enter();
  42
  43         spin_lock_irq(&die_lock);
  44         console_verbose();
  45         bust_spinlocks(1);
  46
  47         pr_emerg("%s [#%d]\n", str, ++die_counter);
  48         print_modules();
  49         show_regs(regs);
  50
  51         ret = notify_die(DIE_OOPS, str, regs, 0, regs->scause, SIGSEGV);
  52
  53         bust_spinlocks(0);
  54         add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
  55         spin_unlock_irq(&die_lock);
  56         oops_exit();
  57
  58         if (in_interrupt())
  59                 panic("Fatal exception in interrupt");
  60         if (panic_on_oops)
  61                 panic("Fatal exception");
  62         if (ret != NOTIFY_STOP)
  63                 do_exit(SIGSEGV);
  64 }
  65
  66 static inline void do_trap_siginfo(int signo, int code,
  67         unsigned long addr, struct task_struct *tsk)
  68 {
  69         siginfo_t info;
  70
  71         info.si_signo = signo;
  72         info.si_errno = 0;
  73         info.si_code = code;
  74         info.si_addr = (void __user *)addr;
  75         force_sig_info(signo, &info, tsk);
  76 }
  77
  78 void do_trap(struct pt_regs *regs, int signo, int code,
  79         unsigned long addr, struct task_struct *tsk)
  80 {
  81         if (show_unhandled_signals && unhandled_signal(tsk, signo)
  82             && printk_ratelimit()) {
  83                 pr_info("%s[%d]: unhandled signal %d code 0x%x at 0x" REG_FMT,
  84                         tsk->comm, task_pid_nr(tsk), signo, code, addr);
  85                 print_vma_addr(KERN_CONT " in ", GET_IP(regs));
  86                 pr_cont("\n");
  87                 show_regs(regs);
  88         }
  89
  90         do_trap_siginfo(signo, code, addr, tsk);
  91 }
  92
  93 static void do_trap_error(struct pt_regs *regs, int signo, int code,
  94         unsigned long addr, const char *str)
  95 {
  96         if (user_mode(regs)) {
  97                 do_trap(regs, signo, code, addr, current);
  98         } else {
  99                 if (!fixup_exception(regs))
 100                         die(regs, str);
 101         }
 102 }
 103
 104 #define DO_ERROR_INFO(name, signo, code, str)                           \
 105 asmlinkage void name(struct pt_regs *regs)                              \
 106 {                                                                       \
 107         do_trap_error(regs, signo, code, regs->sepc, "Oops - " str);    \
 108 }
 109
 110 DO_ERROR_INFO(do_trap_unknown,
 111         SIGILL, ILL_ILLTRP, "unknown exception");
 112 DO_ERROR_INFO(do_trap_insn_misaligned,
 113         SIGBUS, BUS_ADRALN, "instruction address misaligned");
 114 DO_ERROR_INFO(do_trap_insn_fault,
 115         SIGSEGV, SEGV_ACCERR, "instruction access fault");
 116 DO_ERROR_INFO(do_trap_insn_illegal,
 117         SIGILL, ILL_ILLOPC, "illegal instruction");
 118 DO_ERROR_INFO(do_trap_load_misaligned,
 119         SIGBUS, BUS_ADRALN, "load address misaligned");
 120 DO_ERROR_INFO(do_trap_load_fault,
 121         SIGSEGV, SEGV_ACCERR, "load access fault");
 122 DO_ERROR_INFO(do_trap_store_misaligned,
 123         SIGBUS, BUS_ADRALN, "store (or AMO) address misaligned");
 124 DO_ERROR_INFO(do_trap_store_fault,
 125         SIGSEGV, SEGV_ACCERR, "store (or AMO) access fault");
 126 DO_ERROR_INFO(do_trap_ecall_u,
 127         SIGILL, ILL_ILLTRP, "environment call from U-mode");
 128 DO_ERROR_INFO(do_trap_ecall_s,
 129         SIGILL, ILL_ILLTRP, "environment call from S-mode");
 130 DO_ERROR_INFO(do_trap_ecall_m,
 131         SIGILL, ILL_ILLTRP, "environment call from M-mode");
 132
 133 asmlinkage void do_trap_break(struct pt_regs *regs)
 134 {
 135 #ifdef CONFIG_GENERIC_BUG
 136         if (!user_mode(regs)) {
 137                 enum bug_trap_type type;
 138
 139                 type = report_bug(regs->sepc, regs);
 140                 switch (type) {
 141                 case BUG_TRAP_TYPE_NONE:
 142                         break;
 143                 case BUG_TRAP_TYPE_WARN:
 144                         regs->sepc += sizeof(bug_insn_t);
 145                         return;
 146                 case BUG_TRAP_TYPE_BUG:
 147                         die(regs, "Kernel BUG");
 148                 }
 149         }
 150 #endif /* CONFIG_GENERIC_BUG */
 151
 152         do_trap_siginfo(SIGTRAP, TRAP_BRKPT, regs->sepc, current);
 153         regs->sepc += 0x4;
 154 }
 155
 156 #ifdef CONFIG_GENERIC_BUG
 157 int is_valid_bugaddr(unsigned long pc)
 158 {
 159         bug_insn_t insn;
 160
 161         if (pc < PAGE_OFFSET)
 162                 return 0;
 163         if (probe_kernel_address((bug_insn_t __user *)pc, insn))
 164                 return 0;
 165         return (insn == __BUG_INSN);
 166 }
 167 #endif /* CONFIG_GENERIC_BUG */
 168
 169 void __init trap_init(void)
 170 {
 171         /*
 172          * Set sup0 scratch register to 0, indicating to exception vector
 173          * that we are presently executing in the kernel
 174          */
 175         csr_write(sscratch, 0);
 176         /* Set the exception vector address */
 177         csr_write(stvec, &handle_exception);
 178         /* Enable all interrupts */
 179         csr_write(sie, -1);
 180 }