1 // SPDX-License-Identifier: GPL-2.0-only
3 * Copyright (C) 2012 Regents of the University of California
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>
16 #include <linux/module.h>
17 #include <linux/irq.h>
19 #include <asm/processor.h>
20 #include <asm/ptrace.h>
23 int show_unhandled_signals = 1;
25 extern asmlinkage void handle_exception(void);
27 static DEFINE_SPINLOCK(die_lock);
29 void die(struct pt_regs *regs, const char *str)
31 static int die_counter;
36 spin_lock_irq(&die_lock);
40 pr_emerg("%s [#%d]\n", str, ++die_counter);
44 ret = notify_die(DIE_OOPS, str, regs, 0, regs->cause, SIGSEGV);
47 add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
48 spin_unlock_irq(&die_lock);
52 panic("Fatal exception in interrupt");
54 panic("Fatal exception");
55 if (ret != NOTIFY_STOP)
59 void do_trap(struct pt_regs *regs, int signo, int code, unsigned long addr)
61 struct task_struct *tsk = current;
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));
72 force_sig_fault(signo, code, (void __user *)addr);
75 static void do_trap_error(struct pt_regs *regs, int signo, int code,
76 unsigned long addr, const char *str)
78 if (user_mode(regs)) {
79 do_trap(regs, signo, code, addr);
81 if (!fixup_exception(regs))
86 #define DO_ERROR_INFO(name, signo, code, str) \
87 asmlinkage __visible void name(struct pt_regs *regs) \
89 do_trap_error(regs, signo, code, regs->epc, "Oops - " str); \
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_misaligned,
101 SIGBUS, BUS_ADRALN, "load address misaligned");
102 DO_ERROR_INFO(do_trap_load_fault,
103 SIGSEGV, SEGV_ACCERR, "load access fault");
104 DO_ERROR_INFO(do_trap_store_misaligned,
105 SIGBUS, BUS_ADRALN, "store (or AMO) address misaligned");
106 DO_ERROR_INFO(do_trap_store_fault,
107 SIGSEGV, SEGV_ACCERR, "store (or AMO) access fault");
108 DO_ERROR_INFO(do_trap_ecall_u,
109 SIGILL, ILL_ILLTRP, "environment call from U-mode");
110 DO_ERROR_INFO(do_trap_ecall_s,
111 SIGILL, ILL_ILLTRP, "environment call from S-mode");
112 DO_ERROR_INFO(do_trap_ecall_m,
113 SIGILL, ILL_ILLTRP, "environment call from M-mode");
115 static inline unsigned long get_break_insn_length(unsigned long pc)
119 if (probe_kernel_address((bug_insn_t *)pc, insn))
121 return (((insn & __INSN_LENGTH_MASK) == __INSN_LENGTH_32) ? 4UL : 2UL);
124 asmlinkage __visible void do_trap_break(struct pt_regs *regs)
127 force_sig_fault(SIGTRAP, TRAP_BRKPT, (void __user *)regs->epc);
128 else if (report_bug(regs->epc, regs) == BUG_TRAP_TYPE_WARN)
129 regs->epc += get_break_insn_length(regs->epc);
131 die(regs, "Kernel BUG");
134 #ifdef CONFIG_GENERIC_BUG
135 int is_valid_bugaddr(unsigned long pc)
139 if (pc < VMALLOC_START)
141 if (probe_kernel_address((bug_insn_t *)pc, insn))
143 if ((insn & __INSN_LENGTH_MASK) == __INSN_LENGTH_32)
144 return (insn == __BUG_INSN_32);
146 return ((insn & __COMPRESSED_INSN_MASK) == __BUG_INSN_16);
148 #endif /* CONFIG_GENERIC_BUG */
150 void __init trap_init(void)
153 * Set sup0 scratch register to 0, indicating to exception vector
154 * that we are presently executing in the kernel
156 csr_write(CSR_SCRATCH, 0);
157 /* Set the exception vector address */
158 csr_write(CSR_TVEC, &handle_exception);
159 /* Enable interrupts */
160 csr_write(CSR_IE, IE_SIE | IE_EIE);