1 // SPDX-License-Identifier: GPL-2.0-only
3 * Copyright (C) 2012 Regents of the University of California
6 #include <linux/kernel.h>
7 #include <linux/init.h>
8 #include <linux/sched.h>
9 #include <linux/sched/debug.h>
10 #include <linux/sched/signal.h>
11 #include <linux/signal.h>
12 #include <linux/kdebug.h>
13 #include <linux/uaccess.h>
15 #include <linux/module.h>
16 #include <linux/irq.h>
18 #include <asm/processor.h>
19 #include <asm/ptrace.h>
22 int show_unhandled_signals = 1;
24 extern asmlinkage void handle_exception(void);
26 static DEFINE_SPINLOCK(die_lock);
28 void die(struct pt_regs *regs, const char *str)
30 static int die_counter;
35 spin_lock_irq(&die_lock);
39 pr_emerg("%s [#%d]\n", str, ++die_counter);
43 ret = notify_die(DIE_OOPS, str, regs, 0, regs->scause, SIGSEGV);
46 add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
47 spin_unlock_irq(&die_lock);
51 panic("Fatal exception in interrupt");
53 panic("Fatal exception");
54 if (ret != NOTIFY_STOP)
58 void do_trap(struct pt_regs *regs, int signo, int code, unsigned long addr)
60 struct task_struct *tsk = current;
62 if (show_unhandled_signals && unhandled_signal(tsk, signo)
63 && printk_ratelimit()) {
64 pr_info("%s[%d]: unhandled signal %d code 0x%x at 0x" REG_FMT,
65 tsk->comm, task_pid_nr(tsk), signo, code, addr);
66 print_vma_addr(KERN_CONT " in ", instruction_pointer(regs));
71 force_sig_fault(signo, code, (void __user *)addr);
74 static void do_trap_error(struct pt_regs *regs, int signo, int code,
75 unsigned long addr, const char *str)
77 if (user_mode(regs)) {
78 do_trap(regs, signo, code, addr);
80 if (!fixup_exception(regs))
85 #define DO_ERROR_INFO(name, signo, code, str) \
86 asmlinkage void name(struct pt_regs *regs) \
88 do_trap_error(regs, signo, code, regs->sepc, "Oops - " str); \
91 DO_ERROR_INFO(do_trap_unknown,
92 SIGILL, ILL_ILLTRP, "unknown exception");
93 DO_ERROR_INFO(do_trap_insn_misaligned,
94 SIGBUS, BUS_ADRALN, "instruction address misaligned");
95 DO_ERROR_INFO(do_trap_insn_fault,
96 SIGSEGV, SEGV_ACCERR, "instruction access fault");
97 DO_ERROR_INFO(do_trap_insn_illegal,
98 SIGILL, ILL_ILLOPC, "illegal instruction");
99 DO_ERROR_INFO(do_trap_load_misaligned,
100 SIGBUS, BUS_ADRALN, "load address misaligned");
101 DO_ERROR_INFO(do_trap_load_fault,
102 SIGSEGV, SEGV_ACCERR, "load access fault");
103 DO_ERROR_INFO(do_trap_store_misaligned,
104 SIGBUS, BUS_ADRALN, "store (or AMO) address misaligned");
105 DO_ERROR_INFO(do_trap_store_fault,
106 SIGSEGV, SEGV_ACCERR, "store (or AMO) access fault");
107 DO_ERROR_INFO(do_trap_ecall_u,
108 SIGILL, ILL_ILLTRP, "environment call from U-mode");
109 DO_ERROR_INFO(do_trap_ecall_s,
110 SIGILL, ILL_ILLTRP, "environment call from S-mode");
111 DO_ERROR_INFO(do_trap_ecall_m,
112 SIGILL, ILL_ILLTRP, "environment call from M-mode");
114 #ifdef CONFIG_GENERIC_BUG
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);
123 #endif /* CONFIG_GENERIC_BUG */
125 asmlinkage void do_trap_break(struct pt_regs *regs)
127 #ifdef CONFIG_GENERIC_BUG
128 if (!user_mode(regs)) {
129 enum bug_trap_type type;
131 type = report_bug(regs->sepc, regs);
133 case BUG_TRAP_TYPE_NONE:
135 case BUG_TRAP_TYPE_WARN:
136 regs->sepc += get_break_insn_length(regs->sepc);
138 case BUG_TRAP_TYPE_BUG:
139 die(regs, "Kernel BUG");
142 #endif /* CONFIG_GENERIC_BUG */
144 force_sig_fault(SIGTRAP, TRAP_BRKPT, (void __user *)(regs->sepc));
147 #ifdef CONFIG_GENERIC_BUG
148 int is_valid_bugaddr(unsigned long pc)
152 if (pc < VMALLOC_START)
154 if (probe_kernel_address((bug_insn_t *)pc, insn))
156 if ((insn & __INSN_LENGTH_MASK) == __INSN_LENGTH_32)
157 return (insn == __BUG_INSN_32);
159 return ((insn & __COMPRESSED_INSN_MASK) == __BUG_INSN_16);
161 #endif /* CONFIG_GENERIC_BUG */
163 void __init trap_init(void)
166 * Set sup0 scratch register to 0, indicating to exception vector
167 * that we are presently executing in the kernel
169 csr_write(CSR_SSCRATCH, 0);
170 /* Set the exception vector address */
171 csr_write(CSR_STVEC, &handle_exception);
172 /* Enable all interrupts */
173 csr_write(CSR_SIE, -1);