LXR linux/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
  23int show_unhandled_signals = 1;
  24
  25extern asmlinkage void handle_exception(void);
  26
  27static DEFINE_SPINLOCK(die_lock);
  28
  29void 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->scause, 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
  59void 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
  75static 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)                           \
  87asmlinkage __visible void name(struct pt_regs *regs)                    \
  88{                                                                       \
  89        do_trap_error(regs, signo, code, regs->sepc, "Oops - " str);    \
  90}
  91
  92DO_ERROR_INFO(do_trap_unknown,
  93        SIGILL, ILL_ILLTRP, "unknown exception");
  94DO_ERROR_INFO(do_trap_insn_misaligned,
  95        SIGBUS, BUS_ADRALN, "instruction address misaligned");
  96DO_ERROR_INFO(do_trap_insn_fault,
  97        SIGSEGV, SEGV_ACCERR, "instruction access fault");
  98DO_ERROR_INFO(do_trap_insn_illegal,
  99        SIGILL, ILL_ILLOPC, "illegal instruction");
 100DO_ERROR_INFO(do_trap_load_misaligned,
 101        SIGBUS, BUS_ADRALN, "load address misaligned");
 102DO_ERROR_INFO(do_trap_load_fault,
 103        SIGSEGV, SEGV_ACCERR, "load access fault");
 104DO_ERROR_INFO(do_trap_store_misaligned,
 105        SIGBUS, BUS_ADRALN, "store (or AMO) address misaligned");
 106DO_ERROR_INFO(do_trap_store_fault,
 107        SIGSEGV, SEGV_ACCERR, "store (or AMO) access fault");
 108DO_ERROR_INFO(do_trap_ecall_u,
 109        SIGILL, ILL_ILLTRP, "environment call from U-mode");
 110DO_ERROR_INFO(do_trap_ecall_s,
 111        SIGILL, ILL_ILLTRP, "environment call from S-mode");
 112DO_ERROR_INFO(do_trap_ecall_m,
 113        SIGILL, ILL_ILLTRP, "environment call from M-mode");
 114
 115static inline unsigned long get_break_insn_length(unsigned long pc)
 116{
 117        bug_insn_t insn;
 118
 119        if (probe_kernel_address((bug_insn_t *)pc, insn))
 120                return 0;
 121        return (((insn & __INSN_LENGTH_MASK) == __INSN_LENGTH_32) ? 4UL : 2UL);
 122}
 123
 124asmlinkage __visible void do_trap_break(struct pt_regs *regs)
 125{
 126        if (user_mode(regs))
 127                force_sig_fault(SIGTRAP, TRAP_BRKPT, (void __user *)regs->sepc);
 128        else if (report_bug(regs->sepc, regs) == BUG_TRAP_TYPE_WARN)
 129                regs->sepc += get_break_insn_length(regs->sepc);
 130        else
 131                die(regs, "Kernel BUG");
 132}
 133
 134#ifdef CONFIG_GENERIC_BUG
 135int is_valid_bugaddr(unsigned long pc)
 136{
 137        bug_insn_t insn;
 138
 139        if (pc < VMALLOC_START)
 140                return 0;
 141        if (probe_kernel_address((bug_insn_t *)pc, insn))
 142                return 0;
 143        if ((insn & __INSN_LENGTH_MASK) == __INSN_LENGTH_32)
 144                return (insn == __BUG_INSN_32);
 145        else
 146                return ((insn & __COMPRESSED_INSN_MASK) == __BUG_INSN_16);
 147}
 148#endif /* CONFIG_GENERIC_BUG */
 149
 150void __init trap_init(void)
 151{
 152        /*
 153         * Set sup0 scratch register to 0, indicating to exception vector
 154         * that we are presently executing in the kernel
 155         */
 156        csr_write(CSR_SSCRATCH, 0);
 157        /* Set the exception vector address */
 158        csr_write(CSR_STVEC, &handle_exception);
 159        /* Enable all interrupts */
 160        csr_write(CSR_SIE, -1);
 161}
 162