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>
15 #include <linux/kprobes.h>
17 #include <linux/module.h>
18 #include <linux/irq.h>
20 #include <asm/asm-prototypes.h>
22 #include <asm/processor.h>
23 #include <asm/ptrace.h>
26 int show_unhandled_signals = 1;
28 extern asmlinkage void handle_exception(void);
30 static DEFINE_SPINLOCK(die_lock);
32 void die(struct pt_regs *regs, const char *str)
34 static int die_counter;
39 spin_lock_irq(&die_lock);
43 pr_emerg("%s [#%d]\n", str, ++die_counter);
47 ret = notify_die(DIE_OOPS, str, regs, 0, regs->cause, SIGSEGV);
50 add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
51 spin_unlock_irq(&die_lock);
55 panic("Fatal exception in interrupt");
57 panic("Fatal exception");
58 if (ret != NOTIFY_STOP)
62 void do_trap(struct pt_regs *regs, int signo, int code, unsigned long addr)
64 struct task_struct *tsk = current;
66 if (show_unhandled_signals && unhandled_signal(tsk, signo)
67 && printk_ratelimit()) {
68 pr_info("%s[%d]: unhandled signal %d code 0x%x at 0x" REG_FMT,
69 tsk->comm, task_pid_nr(tsk), signo, code, addr);
70 print_vma_addr(KERN_CONT " in ", instruction_pointer(regs));
75 force_sig_fault(signo, code, (void __user *)addr);
78 static void do_trap_error(struct pt_regs *regs, int signo, int code,
79 unsigned long addr, const char *str)
81 current->thread.bad_cause = regs->cause;
83 if (user_mode(regs)) {
84 do_trap(regs, signo, code, addr);
86 if (!fixup_exception(regs))
91 #define DO_ERROR_INFO(name, signo, code, str) \
92 asmlinkage __visible void name(struct pt_regs *regs) \
94 do_trap_error(regs, signo, code, regs->epc, "Oops - " str); \
97 DO_ERROR_INFO(do_trap_unknown,
98 SIGILL, ILL_ILLTRP, "unknown exception");
99 DO_ERROR_INFO(do_trap_insn_misaligned,
100 SIGBUS, BUS_ADRALN, "instruction address misaligned");
101 DO_ERROR_INFO(do_trap_insn_fault,
102 SIGSEGV, SEGV_ACCERR, "instruction access fault");
103 DO_ERROR_INFO(do_trap_insn_illegal,
104 SIGILL, ILL_ILLOPC, "illegal instruction");
105 DO_ERROR_INFO(do_trap_load_fault,
106 SIGSEGV, SEGV_ACCERR, "load access fault");
107 #ifndef CONFIG_RISCV_M_MODE
108 DO_ERROR_INFO(do_trap_load_misaligned,
109 SIGBUS, BUS_ADRALN, "Oops - load address misaligned");
110 DO_ERROR_INFO(do_trap_store_misaligned,
111 SIGBUS, BUS_ADRALN, "Oops - store (or AMO) address misaligned");
113 int handle_misaligned_load(struct pt_regs *regs);
114 int handle_misaligned_store(struct pt_regs *regs);
116 asmlinkage void do_trap_load_misaligned(struct pt_regs *regs)
118 if (!handle_misaligned_load(regs))
120 do_trap_error(regs, SIGBUS, BUS_ADRALN, regs->epc,
121 "Oops - load address misaligned");
124 asmlinkage void do_trap_store_misaligned(struct pt_regs *regs)
126 if (!handle_misaligned_store(regs))
128 do_trap_error(regs, SIGBUS, BUS_ADRALN, regs->epc,
129 "Oops - store (or AMO) address misaligned");
132 DO_ERROR_INFO(do_trap_store_fault,
133 SIGSEGV, SEGV_ACCERR, "store (or AMO) access fault");
134 DO_ERROR_INFO(do_trap_ecall_u,
135 SIGILL, ILL_ILLTRP, "environment call from U-mode");
136 DO_ERROR_INFO(do_trap_ecall_s,
137 SIGILL, ILL_ILLTRP, "environment call from S-mode");
138 DO_ERROR_INFO(do_trap_ecall_m,
139 SIGILL, ILL_ILLTRP, "environment call from M-mode");
141 static inline unsigned long get_break_insn_length(unsigned long pc)
145 if (get_kernel_nofault(insn, (bug_insn_t *)pc))
148 return GET_INSN_LENGTH(insn);
151 asmlinkage __visible void do_trap_break(struct pt_regs *regs)
153 #ifdef CONFIG_KPROBES
154 if (kprobe_single_step_handler(regs))
157 if (kprobe_breakpoint_handler(regs))
160 #ifdef CONFIG_UPROBES
161 if (uprobe_single_step_handler(regs))
164 if (uprobe_breakpoint_handler(regs))
167 current->thread.bad_cause = regs->cause;
170 force_sig_fault(SIGTRAP, TRAP_BRKPT, (void __user *)regs->epc);
172 else if (notify_die(DIE_TRAP, "EBREAK", regs, 0, regs->cause, SIGTRAP)
176 else if (report_bug(regs->epc, regs) == BUG_TRAP_TYPE_WARN)
177 regs->epc += get_break_insn_length(regs->epc);
179 die(regs, "Kernel BUG");
181 NOKPROBE_SYMBOL(do_trap_break);
183 #ifdef CONFIG_GENERIC_BUG
184 int is_valid_bugaddr(unsigned long pc)
188 if (pc < VMALLOC_START)
190 if (get_kernel_nofault(insn, (bug_insn_t *)pc))
192 if ((insn & __INSN_LENGTH_MASK) == __INSN_LENGTH_32)
193 return (insn == __BUG_INSN_32);
195 return ((insn & __COMPRESSED_INSN_MASK) == __BUG_INSN_16);
197 #endif /* CONFIG_GENERIC_BUG */
199 /* stvec & scratch is already set from head.S */
200 void __init trap_init(void)