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_misaligned, 101 SIGBUS, BUS_ADRALN, "load address misaligned"); 102 DO_ERROR_INFO(do_trap_load_fault, 103 SIGSEGV, SEGV_ACCERR, "load access fault"); 104 DO_ERROR_INFO(do_trap_store_misaligned, 105 SIGBUS, BUS_ADRALN, "store (or AMO) address misaligned"); 106 DO_ERROR_INFO(do_trap_store_fault, 107 SIGSEGV, SEGV_ACCERR, "store (or AMO) access fault"); 108 DO_ERROR_INFO(do_trap_ecall_u, 109 SIGILL, ILL_ILLTRP, "environment call from U-mode"); 110 DO_ERROR_INFO(do_trap_ecall_s, 111 SIGILL, ILL_ILLTRP, "environment call from S-mode"); 112 DO_ERROR_INFO(do_trap_ecall_m, 113 SIGILL, ILL_ILLTRP, "environment call from M-mode"); 114 115 static inline unsigned long get_break_insn_length(unsigned long pc) 116 { 117 bug_insn_t insn; 118 119 if (probe_kernel_address((bug_insn_t *)pc, insn)) 120 return 0; 121 return (((insn & __INSN_LENGTH_MASK) == __INSN_LENGTH_32) ? 4UL : 2UL); 122 } 123 124 asmlinkage __visible void do_trap_break(struct pt_regs *regs) 125 { 126 if (user_mode(regs)) 127 force_sig_fault(SIGTRAP, TRAP_BRKPT, (void __user *)regs->epc); 128 else if (report_bug(regs->epc, regs) == BUG_TRAP_TYPE_WARN) 129 regs->epc += get_break_insn_length(regs->epc); 130 else 131 die(regs, "Kernel BUG"); 132 } 133 134 #ifdef CONFIG_GENERIC_BUG 135 int is_valid_bugaddr(unsigned long pc) 136 { 137 bug_insn_t insn; 138 139 if (pc < VMALLOC_START) 140 return 0; 141 if (probe_kernel_address((bug_insn_t *)pc, insn)) 142 return 0; 143 if ((insn & __INSN_LENGTH_MASK) == __INSN_LENGTH_32) 144 return (insn == __BUG_INSN_32); 145 else 146 return ((insn & __COMPRESSED_INSN_MASK) == __BUG_INSN_16); 147 } 148 #endif /* CONFIG_GENERIC_BUG */ 149 150 void __init trap_init(void) 151 { 152 /* 153 * Set sup0 scratch register to 0, indicating to exception vector 154 * that we are presently executing in the kernel 155 */ 156 csr_write(CSR_SCRATCH, 0); 157 /* Set the exception vector address */ 158 csr_write(CSR_TVEC, &handle_exception); 159 /* Enable all interrupts */ 160 csr_write(CSR_IE, -1); 161 } 162