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 extern asmlinkage void handle_exception(void); 29 30 static DEFINE_SPINLOCK(die_lock); 31 32 void die(struct pt_regs *regs, const char *str) 33 { 34 static int die_counter; 35 int ret; 36 37 oops_enter(); 38 39 spin_lock_irq(&die_lock); 40 console_verbose(); 41 bust_spinlocks(1); 42 43 pr_emerg("%s [#%d]\n", str, ++die_counter); 44 print_modules(); 45 show_regs(regs); 46 47 ret = notify_die(DIE_OOPS, str, regs, 0, regs->cause, SIGSEGV); 48 49 bust_spinlocks(0); 50 add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE); 51 spin_unlock_irq(&die_lock); 52 oops_exit(); 53 54 if (in_interrupt()) 55 panic("Fatal exception in interrupt"); 56 if (panic_on_oops) 57 panic("Fatal exception"); 58 if (ret != NOTIFY_STOP) 59 do_exit(SIGSEGV); 60 } 61 62 void do_trap(struct pt_regs *regs, int signo, int code, unsigned long addr) 63 { 64 struct task_struct *tsk = current; 65 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)); 71 pr_cont("\n"); 72 __show_regs(regs); 73 } 74 75 force_sig_fault(signo, code, (void __user *)addr); 76 } 77 78 static void do_trap_error(struct pt_regs *regs, int signo, int code, 79 unsigned long addr, const char *str) 80 { 81 current->thread.bad_cause = regs->cause; 82 83 if (user_mode(regs)) { 84 do_trap(regs, signo, code, addr); 85 } else { 86 if (!fixup_exception(regs)) 87 die(regs, str); 88 } 89 } 90 91 #define DO_ERROR_INFO(name, signo, code, str) \ 92 asmlinkage __visible void name(struct pt_regs *regs) \ 93 { \ 94 do_trap_error(regs, signo, code, regs->epc, "Oops - " str); \ 95 } 96 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"); 112 #else 113 int handle_misaligned_load(struct pt_regs *regs); 114 int handle_misaligned_store(struct pt_regs *regs); 115 116 asmlinkage void do_trap_load_misaligned(struct pt_regs *regs) 117 { 118 if (!handle_misaligned_load(regs)) 119 return; 120 do_trap_error(regs, SIGBUS, BUS_ADRALN, regs->epc, 121 "Oops - load address misaligned"); 122 } 123 124 asmlinkage void do_trap_store_misaligned(struct pt_regs *regs) 125 { 126 if (!handle_misaligned_store(regs)) 127 return; 128 do_trap_error(regs, SIGBUS, BUS_ADRALN, regs->epc, 129 "Oops - store (or AMO) address misaligned"); 130 } 131 #endif 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"); 140 141 static inline unsigned long get_break_insn_length(unsigned long pc) 142 { 143 bug_insn_t insn; 144 145 if (get_kernel_nofault(insn, (bug_insn_t *)pc)) 146 return 0; 147 148 return GET_INSN_LENGTH(insn); 149 } 150 151 asmlinkage __visible void do_trap_break(struct pt_regs *regs) 152 { 153 #ifdef CONFIG_KPROBES 154 if (kprobe_single_step_handler(regs)) 155 return; 156 157 if (kprobe_breakpoint_handler(regs)) 158 return; 159 #endif 160 #ifdef CONFIG_UPROBES 161 if (uprobe_single_step_handler(regs)) 162 return; 163 164 if (uprobe_breakpoint_handler(regs)) 165 return; 166 #endif 167 current->thread.bad_cause = regs->cause; 168 169 if (user_mode(regs)) 170 force_sig_fault(SIGTRAP, TRAP_BRKPT, (void __user *)regs->epc); 171 #ifdef CONFIG_KGDB 172 else if (notify_die(DIE_TRAP, "EBREAK", regs, 0, regs->cause, SIGTRAP) 173 == NOTIFY_STOP) 174 return; 175 #endif 176 else if (report_bug(regs->epc, regs) == BUG_TRAP_TYPE_WARN) 177 regs->epc += get_break_insn_length(regs->epc); 178 else 179 die(regs, "Kernel BUG"); 180 } 181 NOKPROBE_SYMBOL(do_trap_break); 182 183 #ifdef CONFIG_GENERIC_BUG 184 int is_valid_bugaddr(unsigned long pc) 185 { 186 bug_insn_t insn; 187 188 if (pc < VMALLOC_START) 189 return 0; 190 if (get_kernel_nofault(insn, (bug_insn_t *)pc)) 191 return 0; 192 if ((insn & __INSN_LENGTH_MASK) == __INSN_LENGTH_32) 193 return (insn == __BUG_INSN_32); 194 else 195 return ((insn & __COMPRESSED_INSN_MASK) == __BUG_INSN_16); 196 } 197 #endif /* CONFIG_GENERIC_BUG */ 198 199 /* stvec & scratch is already set from head.S */ 200 void trap_init(void) 201 { 202 } 203