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,
59 unsigned long addr, struct task_struct *tsk)
61 if (show_unhandled_signals && unhandled_signal(tsk, signo)
62 && printk_ratelimit()) {
63 pr_info("%s[%d]: unhandled signal %d code 0x%x at 0x" REG_FMT,
64 tsk->comm, task_pid_nr(tsk), signo, code, addr);
65 print_vma_addr(KERN_CONT " in ", instruction_pointer(regs));
70 force_sig_fault(signo, code, (void __user *)addr, tsk);
73 static void do_trap_error(struct pt_regs *regs, int signo, int code,
74 unsigned long addr, const char *str)
76 if (user_mode(regs)) {
77 do_trap(regs, signo, code, addr, current);
79 if (!fixup_exception(regs))
84 #define DO_ERROR_INFO(name, signo, code, str) \
85 asmlinkage void name(struct pt_regs *regs) \
87 do_trap_error(regs, signo, code, regs->sepc, "Oops - " str); \
90 DO_ERROR_INFO(do_trap_unknown,
91 SIGILL, ILL_ILLTRP, "unknown exception");
92 DO_ERROR_INFO(do_trap_insn_misaligned,
93 SIGBUS, BUS_ADRALN, "instruction address misaligned");
94 DO_ERROR_INFO(do_trap_insn_fault,
95 SIGSEGV, SEGV_ACCERR, "instruction access fault");
96 DO_ERROR_INFO(do_trap_insn_illegal,
97 SIGILL, ILL_ILLOPC, "illegal instruction");
98 DO_ERROR_INFO(do_trap_load_misaligned,
99 SIGBUS, BUS_ADRALN, "load address misaligned");
100 DO_ERROR_INFO(do_trap_load_fault,
101 SIGSEGV, SEGV_ACCERR, "load access fault");
102 DO_ERROR_INFO(do_trap_store_misaligned,
103 SIGBUS, BUS_ADRALN, "store (or AMO) address misaligned");
104 DO_ERROR_INFO(do_trap_store_fault,
105 SIGSEGV, SEGV_ACCERR, "store (or AMO) access fault");
106 DO_ERROR_INFO(do_trap_ecall_u,
107 SIGILL, ILL_ILLTRP, "environment call from U-mode");
108 DO_ERROR_INFO(do_trap_ecall_s,
109 SIGILL, ILL_ILLTRP, "environment call from S-mode");
110 DO_ERROR_INFO(do_trap_ecall_m,
111 SIGILL, ILL_ILLTRP, "environment call from M-mode");
113 #ifdef CONFIG_GENERIC_BUG
114 static inline unsigned long get_break_insn_length(unsigned long pc)
118 if (probe_kernel_address((bug_insn_t *)pc, insn))
120 return (((insn & __INSN_LENGTH_MASK) == __INSN_LENGTH_32) ? 4UL : 2UL);
122 #endif /* CONFIG_GENERIC_BUG */
124 asmlinkage void do_trap_break(struct pt_regs *regs)
126 #ifdef CONFIG_GENERIC_BUG
127 if (!user_mode(regs)) {
128 enum bug_trap_type type;
130 type = report_bug(regs->sepc, regs);
132 case BUG_TRAP_TYPE_NONE:
134 case BUG_TRAP_TYPE_WARN:
135 regs->sepc += get_break_insn_length(regs->sepc);
137 case BUG_TRAP_TYPE_BUG:
138 die(regs, "Kernel BUG");
141 #endif /* CONFIG_GENERIC_BUG */
143 force_sig_fault(SIGTRAP, TRAP_BRKPT, (void __user *)(regs->sepc), current);
146 #ifdef CONFIG_GENERIC_BUG
147 int is_valid_bugaddr(unsigned long pc)
151 if (pc < VMALLOC_START)
153 if (probe_kernel_address((bug_insn_t *)pc, insn))
155 if ((insn & __INSN_LENGTH_MASK) == __INSN_LENGTH_32)
156 return (insn == __BUG_INSN_32);
158 return ((insn & __COMPRESSED_INSN_MASK) == __BUG_INSN_16);
160 #endif /* CONFIG_GENERIC_BUG */
162 void __init trap_init(void)
165 * Set sup0 scratch register to 0, indicating to exception vector
166 * that we are presently executing in the kernel
168 csr_write(CSR_SSCRATCH, 0);
169 /* Set the exception vector address */
170 csr_write(CSR_STVEC, &handle_exception);
171 /* Enable all interrupts */
172 csr_write(CSR_SIE, -1);