LXR linux/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
  30int show_unhandled_signals = 1;
  31
  32extern asmlinkage void handle_exception(void);
  33
  34static DEFINE_SPINLOCK(die_lock);
  35
  36void 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
  66void do_trap(struct pt_regs *regs, int signo, int code,
  67        unsigned long addr, struct task_struct *tsk)
  68{
  69        if (show_unhandled_signals && unhandled_signal(tsk, signo)
  70            && printk_ratelimit()) {
  71                pr_info("%s[%d]: unhandled signal %d code 0x%x at 0x" REG_FMT,
  72                        tsk->comm, task_pid_nr(tsk), signo, code, addr);
  73                print_vma_addr(KERN_CONT " in ", GET_IP(regs));
  74                pr_cont("\n");
  75                show_regs(regs);
  76        }
  77
  78        force_sig_fault(signo, code, (void __user *)addr, tsk);
  79}
  80
  81static void do_trap_error(struct pt_regs *regs, int signo, int code,
  82        unsigned long addr, const char *str)
  83{
  84        if (user_mode(regs)) {
  85                do_trap(regs, signo, code, addr, current);
  86        } else {
  87                if (!fixup_exception(regs))
  88                        die(regs, str);
  89        }
  90}
  91
  92#define DO_ERROR_INFO(name, signo, code, str)                           \
  93asmlinkage void name(struct pt_regs *regs)                              \
  94{                                                                       \
  95        do_trap_error(regs, signo, code, regs->sepc, "Oops - " str);    \
  96}
  97
  98DO_ERROR_INFO(do_trap_unknown,
  99        SIGILL, ILL_ILLTRP, "unknown exception");
 100DO_ERROR_INFO(do_trap_insn_misaligned,
 101        SIGBUS, BUS_ADRALN, "instruction address misaligned");
 102DO_ERROR_INFO(do_trap_insn_fault,
 103        SIGSEGV, SEGV_ACCERR, "instruction access fault");
 104DO_ERROR_INFO(do_trap_insn_illegal,
 105        SIGILL, ILL_ILLOPC, "illegal instruction");
 106DO_ERROR_INFO(do_trap_load_misaligned,
 107        SIGBUS, BUS_ADRALN, "load address misaligned");
 108DO_ERROR_INFO(do_trap_load_fault,
 109        SIGSEGV, SEGV_ACCERR, "load access fault");
 110DO_ERROR_INFO(do_trap_store_misaligned,
 111        SIGBUS, BUS_ADRALN, "store (or AMO) address misaligned");
 112DO_ERROR_INFO(do_trap_store_fault,
 113        SIGSEGV, SEGV_ACCERR, "store (or AMO) access fault");
 114DO_ERROR_INFO(do_trap_ecall_u,
 115        SIGILL, ILL_ILLTRP, "environment call from U-mode");
 116DO_ERROR_INFO(do_trap_ecall_s,
 117        SIGILL, ILL_ILLTRP, "environment call from S-mode");
 118DO_ERROR_INFO(do_trap_ecall_m,
 119        SIGILL, ILL_ILLTRP, "environment call from M-mode");
 120
 121asmlinkage void do_trap_break(struct pt_regs *regs)
 122{
 123#ifdef CONFIG_GENERIC_BUG
 124        if (!user_mode(regs)) {
 125                enum bug_trap_type type;
 126
 127                type = report_bug(regs->sepc, regs);
 128                switch (type) {
 129                case BUG_TRAP_TYPE_NONE:
 130                        break;
 131                case BUG_TRAP_TYPE_WARN:
 132                        regs->sepc += sizeof(bug_insn_t);
 133                        return;
 134                case BUG_TRAP_TYPE_BUG:
 135                        die(regs, "Kernel BUG");
 136                }
 137        }
 138#endif /* CONFIG_GENERIC_BUG */
 139
 140        force_sig_fault(SIGTRAP, TRAP_BRKPT, (void __user *)(regs->sepc), current);
 141        regs->sepc += 0x4;
 142}
 143
 144#ifdef CONFIG_GENERIC_BUG
 145int is_valid_bugaddr(unsigned long pc)
 146{
 147        bug_insn_t insn;
 148
 149        if (pc < PAGE_OFFSET)
 150                return 0;
 151        if (probe_kernel_address((bug_insn_t *)pc, insn))
 152                return 0;
 153        return (insn == __BUG_INSN);
 154}
 155#endif /* CONFIG_GENERIC_BUG */
 156
 157void __init trap_init(void)
 158{
 159        /*
 160         * Set sup0 scratch register to 0, indicating to exception vector
 161         * that we are presently executing in the kernel
 162         */
 163        csr_write(sscratch, 0);
 164        /* Set the exception vector address */
 165        csr_write(stvec, &handle_exception);
 166        /* Enable all interrupts */
 167        csr_write(sie, -1);
 168}
 169