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/mm.h> 16 #include <linux/module.h> 17 #include <linux/irq.h> 18 19 #include <asm/processor.h> 20 #include <asm/ptrace.h> 21 #include <asm/csr.h> 22 23 int show_unhandled_signals = 1; 24 25 extern asmlinkage void handle_exception(void); 26 27 static DEFINE_SPINLOCK(die_lock); 28 29 void die(struct pt_regs *regs, const char *str) 30 { 31 static int die_counter; 32 int ret; 33 34 oops_enter(); 35 36 spin_lock_irq(&die_lock); 37 console_verbose(); 38 bust_spinlocks(1); 39 40 pr_emerg("%s [#%d]\n", str, ++die_counter); 41 print_modules(); 42 show_regs(regs); 43 44 ret = notify_die(DIE_OOPS, str, regs, 0, regs->cause, SIGSEGV); 45 46 bust_spinlocks(0); 47 add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE); 48 spin_unlock_irq(&die_lock); 49 oops_exit(); 50 51 if (in_interrupt()) 52 panic("Fatal exception in interrupt"); 53 if (panic_on_oops) 54 panic("Fatal exception"); 55 if (ret != NOTIFY_STOP) 56 do_exit(SIGSEGV); 57 } 58 59 void do_trap(struct pt_regs *regs, int signo, int code, unsigned long addr) 60 { 61 struct task_struct *tsk = current; 62 63 if (show_unhandled_signals && unhandled_signal(tsk, signo) 64 && printk_ratelimit()) { 65 pr_info("%s[%d]: unhandled signal %d code 0x%x at 0x" REG_FMT, 66 tsk->comm, task_pid_nr(tsk), signo, code, addr); 67 print_vma_addr(KERN_CONT " in ", instruction_pointer(regs)); 68 pr_cont("\n"); 69 show_regs(regs); 70 } 71 72 force_sig_fault(signo, code, (void __user *)addr); 73 } 74 75 static void do_trap_error(struct pt_regs *regs, int signo, int code, 76 unsigned long addr, const char *str) 77 { 78 if (user_mode(regs)) { 79 do_trap(regs, signo, code, addr); 80 } else { 81 if (!fixup_exception(regs)) 82 die(regs, str); 83 } 84 } 85 86 #define DO_ERROR_INFO(name, signo, code, str) \ 87 asmlinkage __visible void name(struct pt_regs *regs) \ 88 { \ 89 do_trap_error(regs, signo, code, regs->epc, "Oops - " str); \ 90 } 91 92 DO_ERROR_INFO(do_trap_unknown, 93 SIGILL, ILL_ILLTRP, "unknown exception"); 94 DO_ERROR_INFO(do_trap_insn_misaligned, 95 SIGBUS, BUS_ADRALN, "instruction address misaligned"); 96 DO_ERROR_INFO(do_trap_insn_fault, 97 SIGSEGV, SEGV_ACCERR, "instruction access fault"); 98 DO_ERROR_INFO(do_trap_insn_illegal, 99 SIGILL, ILL_ILLOPC, "illegal instruction"); 100 DO_ERROR_INFO(do_trap_load_fault, 101 SIGSEGV, SEGV_ACCERR, "load access fault"); 102 #ifndef CONFIG_RISCV_M_MODE 103 DO_ERROR_INFO(do_trap_load_misaligned, 104 SIGBUS, BUS_ADRALN, "Oops - load address misaligned"); 105 DO_ERROR_INFO(do_trap_store_misaligned, 106 SIGBUS, BUS_ADRALN, "Oops - store (or AMO) address misaligned"); 107 #else 108 int handle_misaligned_load(struct pt_regs *regs); 109 int handle_misaligned_store(struct pt_regs *regs); 110 111 asmlinkage void do_trap_load_misaligned(struct pt_regs *regs) 112 { 113 if (!handle_misaligned_load(regs)) 114 return; 115 do_trap_error(regs, SIGBUS, BUS_ADRALN, regs->epc, 116 "Oops - load address misaligned"); 117 } 118 119 asmlinkage void do_trap_store_misaligned(struct pt_regs *regs) 120 { 121 if (!handle_misaligned_store(regs)) 122 return; 123 do_trap_error(regs, SIGBUS, BUS_ADRALN, regs->epc, 124 "Oops - store (or AMO) address misaligned"); 125 } 126 #endif 127 DO_ERROR_INFO(do_trap_store_fault, 128 SIGSEGV, SEGV_ACCERR, "store (or AMO) access fault"); 129 DO_ERROR_INFO(do_trap_ecall_u, 130 SIGILL, ILL_ILLTRP, "environment call from U-mode"); 131 DO_ERROR_INFO(do_trap_ecall_s, 132 SIGILL, ILL_ILLTRP, "environment call from S-mode"); 133 DO_ERROR_INFO(do_trap_ecall_m, 134 SIGILL, ILL_ILLTRP, "environment call from M-mode"); 135 136 static inline unsigned long get_break_insn_length(unsigned long pc) 137 { 138 bug_insn_t insn; 139 140 if (get_kernel_nofault(insn, (bug_insn_t *)pc)) 141 return 0; 142 143 return GET_INSN_LENGTH(insn); 144 } 145 146 asmlinkage __visible void do_trap_break(struct pt_regs *regs) 147 { 148 if (user_mode(regs)) 149 force_sig_fault(SIGTRAP, TRAP_BRKPT, (void __user *)regs->epc); 150 #ifdef CONFIG_KGDB 151 else if (notify_die(DIE_TRAP, "EBREAK", regs, 0, regs->cause, SIGTRAP) 152 == NOTIFY_STOP) 153 return; 154 #endif 155 else if (report_bug(regs->epc, regs) == BUG_TRAP_TYPE_WARN) 156 regs->epc += get_break_insn_length(regs->epc); 157 else 158 die(regs, "Kernel BUG"); 159 } 160 161 #ifdef CONFIG_GENERIC_BUG 162 int is_valid_bugaddr(unsigned long pc) 163 { 164 bug_insn_t insn; 165 166 if (pc < VMALLOC_START) 167 return 0; 168 if (get_kernel_nofault(insn, (bug_insn_t *)pc)) 169 return 0; 170 if ((insn & __INSN_LENGTH_MASK) == __INSN_LENGTH_32) 171 return (insn == __BUG_INSN_32); 172 else 173 return ((insn & __COMPRESSED_INSN_MASK) == __BUG_INSN_16); 174 } 175 #endif /* CONFIG_GENERIC_BUG */ 176 177 void trap_init(void) 178 { 179 /* 180 * Set sup0 scratch register to 0, indicating to exception vector 181 * that we are presently executing in the kernel 182 */ 183 csr_write(CSR_SCRATCH, 0); 184 /* Set the exception vector address */ 185 csr_write(CSR_TVEC, &handle_exception); 186 } 187