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/kprobes.h> 16 #include <linux/mm.h> 17 #include <linux/module.h> 18 #include <linux/irq.h> 19 20 #include <asm/asm-prototypes.h> 21 #include <asm/bug.h> 22 #include <asm/processor.h> 23 #include <asm/ptrace.h> 24 #include <asm/csr.h> 25 26 int show_unhandled_signals = 1; 27 28 static DEFINE_SPINLOCK(die_lock); 29 30 void die(struct pt_regs *regs, const char *str) 31 { 32 static int die_counter; 33 int ret; 34 35 oops_enter(); 36 37 spin_lock_irq(&die_lock); 38 console_verbose(); 39 bust_spinlocks(1); 40 41 pr_emerg("%s [#%d]\n", str, ++die_counter); 42 print_modules(); 43 show_regs(regs); 44 45 ret = notify_die(DIE_OOPS, str, regs, 0, regs->cause, SIGSEGV); 46 47 bust_spinlocks(0); 48 add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE); 49 spin_unlock_irq(&die_lock); 50 oops_exit(); 51 52 if (in_interrupt()) 53 panic("Fatal exception in interrupt"); 54 if (panic_on_oops) 55 panic("Fatal exception"); 56 if (ret != NOTIFY_STOP) 57 do_exit(SIGSEGV); 58 } 59 60 void do_trap(struct pt_regs *regs, int signo, int code, unsigned long addr) 61 { 62 struct task_struct *tsk = current; 63 64 if (show_unhandled_signals && unhandled_signal(tsk, signo) 65 && printk_ratelimit()) { 66 pr_info("%s[%d]: unhandled signal %d code 0x%x at 0x" REG_FMT, 67 tsk->comm, task_pid_nr(tsk), signo, code, addr); 68 print_vma_addr(KERN_CONT " in ", instruction_pointer(regs)); 69 pr_cont("\n"); 70 __show_regs(regs); 71 } 72 73 force_sig_fault(signo, code, (void __user *)addr); 74 } 75 76 static void do_trap_error(struct pt_regs *regs, int signo, int code, 77 unsigned long addr, const char *str) 78 { 79 current->thread.bad_cause = regs->cause; 80 81 if (user_mode(regs)) { 82 do_trap(regs, signo, code, addr); 83 } else { 84 if (!fixup_exception(regs)) 85 die(regs, str); 86 } 87 } 88 89 #define DO_ERROR_INFO(name, signo, code, str) \ 90 asmlinkage __visible void name(struct pt_regs *regs) \ 91 { \ 92 do_trap_error(regs, signo, code, regs->epc, "Oops - " str); \ 93 } 94 95 DO_ERROR_INFO(do_trap_unknown, 96 SIGILL, ILL_ILLTRP, "unknown exception"); 97 DO_ERROR_INFO(do_trap_insn_misaligned, 98 SIGBUS, BUS_ADRALN, "instruction address misaligned"); 99 DO_ERROR_INFO(do_trap_insn_fault, 100 SIGSEGV, SEGV_ACCERR, "instruction access fault"); 101 DO_ERROR_INFO(do_trap_insn_illegal, 102 SIGILL, ILL_ILLOPC, "illegal instruction"); 103 DO_ERROR_INFO(do_trap_load_fault, 104 SIGSEGV, SEGV_ACCERR, "load access fault"); 105 #ifndef CONFIG_RISCV_M_MODE 106 DO_ERROR_INFO(do_trap_load_misaligned, 107 SIGBUS, BUS_ADRALN, "Oops - load address misaligned"); 108 DO_ERROR_INFO(do_trap_store_misaligned, 109 SIGBUS, BUS_ADRALN, "Oops - store (or AMO) address misaligned"); 110 #else 111 int handle_misaligned_load(struct pt_regs *regs); 112 int handle_misaligned_store(struct pt_regs *regs); 113 114 asmlinkage void do_trap_load_misaligned(struct pt_regs *regs) 115 { 116 if (!handle_misaligned_load(regs)) 117 return; 118 do_trap_error(regs, SIGBUS, BUS_ADRALN, regs->epc, 119 "Oops - load address misaligned"); 120 } 121 122 asmlinkage void do_trap_store_misaligned(struct pt_regs *regs) 123 { 124 if (!handle_misaligned_store(regs)) 125 return; 126 do_trap_error(regs, SIGBUS, BUS_ADRALN, regs->epc, 127 "Oops - store (or AMO) address misaligned"); 128 } 129 #endif 130 DO_ERROR_INFO(do_trap_store_fault, 131 SIGSEGV, SEGV_ACCERR, "store (or AMO) access fault"); 132 DO_ERROR_INFO(do_trap_ecall_u, 133 SIGILL, ILL_ILLTRP, "environment call from U-mode"); 134 DO_ERROR_INFO(do_trap_ecall_s, 135 SIGILL, ILL_ILLTRP, "environment call from S-mode"); 136 DO_ERROR_INFO(do_trap_ecall_m, 137 SIGILL, ILL_ILLTRP, "environment call from M-mode"); 138 139 static inline unsigned long get_break_insn_length(unsigned long pc) 140 { 141 bug_insn_t insn; 142 143 if (get_kernel_nofault(insn, (bug_insn_t *)pc)) 144 return 0; 145 146 return GET_INSN_LENGTH(insn); 147 } 148 149 asmlinkage __visible void do_trap_break(struct pt_regs *regs) 150 { 151 #ifdef CONFIG_KPROBES 152 if (kprobe_single_step_handler(regs)) 153 return; 154 155 if (kprobe_breakpoint_handler(regs)) 156 return; 157 #endif 158 #ifdef CONFIG_UPROBES 159 if (uprobe_single_step_handler(regs)) 160 return; 161 162 if (uprobe_breakpoint_handler(regs)) 163 return; 164 #endif 165 current->thread.bad_cause = regs->cause; 166 167 if (user_mode(regs)) 168 force_sig_fault(SIGTRAP, TRAP_BRKPT, (void __user *)regs->epc); 169 #ifdef CONFIG_KGDB 170 else if (notify_die(DIE_TRAP, "EBREAK", regs, 0, regs->cause, SIGTRAP) 171 == NOTIFY_STOP) 172 return; 173 #endif 174 else if (report_bug(regs->epc, regs) == BUG_TRAP_TYPE_WARN) 175 regs->epc += get_break_insn_length(regs->epc); 176 else 177 die(regs, "Kernel BUG"); 178 } 179 NOKPROBE_SYMBOL(do_trap_break); 180 181 #ifdef CONFIG_GENERIC_BUG 182 int is_valid_bugaddr(unsigned long pc) 183 { 184 bug_insn_t insn; 185 186 if (pc < VMALLOC_START) 187 return 0; 188 if (get_kernel_nofault(insn, (bug_insn_t *)pc)) 189 return 0; 190 if ((insn & __INSN_LENGTH_MASK) == __INSN_LENGTH_32) 191 return (insn == __BUG_INSN_32); 192 else 193 return ((insn & __COMPRESSED_INSN_MASK) == __BUG_INSN_16); 194 } 195 #endif /* CONFIG_GENERIC_BUG */ 196 197 /* stvec & scratch is already set from head.S */ 198 void __init trap_init(void) 199 { 200 } 201