1 /* 2 * Copyright (C) 2012 Regents of the University of California 3 * 4 * This program is free software; you can redistribute it and/or 5 * modify it under the terms of the GNU General Public License 6 * as published by the Free Software Foundation, version 2. 7 * 8 * This program is distributed in the hope that it will be useful, 9 * but WITHOUT ANY WARRANTY; without even the implied warranty of 10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 11 * GNU General Public License for more details. 12 */ 13 14 #include <linux/kernel.h> 15 #include <linux/init.h> 16 #include <linux/sched.h> 17 #include <linux/sched/debug.h> 18 #include <linux/sched/signal.h> 19 #include <linux/signal.h> 20 #include <linux/kdebug.h> 21 #include <linux/uaccess.h> 22 #include <linux/mm.h> 23 #include <linux/module.h> 24 #include <linux/irq.h> 25 26 #include <asm/processor.h> 27 #include <asm/ptrace.h> 28 #include <asm/csr.h> 29 30 int show_unhandled_signals = 1; 31 32 extern asmlinkage void handle_exception(void); 33 34 static DEFINE_SPINLOCK(die_lock); 35 36 void die(struct pt_regs *regs, const char *str) 37 { 38 static int die_counter; 39 int ret; 40 41 oops_enter(); 42 43 spin_lock_irq(&die_lock); 44 console_verbose(); 45 bust_spinlocks(1); 46 47 pr_emerg("%s [#%d]\n", str, ++die_counter); 48 print_modules(); 49 show_regs(regs); 50 51 ret = notify_die(DIE_OOPS, str, regs, 0, regs->scause, SIGSEGV); 52 53 bust_spinlocks(0); 54 add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE); 55 spin_unlock_irq(&die_lock); 56 oops_exit(); 57 58 if (in_interrupt()) 59 panic("Fatal exception in interrupt"); 60 if (panic_on_oops) 61 panic("Fatal exception"); 62 if (ret != NOTIFY_STOP) 63 do_exit(SIGSEGV); 64 } 65 66 void do_trap(struct pt_regs *regs, int signo, int code, 67 unsigned long addr, struct task_struct *tsk) 68 { 69 if (show_unhandled_signals && unhandled_signal(tsk, signo) 70 && printk_ratelimit()) { 71 pr_info("%s[%d]: unhandled signal %d code 0x%x at 0x" REG_FMT, 72 tsk->comm, task_pid_nr(tsk), signo, code, addr); 73 print_vma_addr(KERN_CONT " in ", instruction_pointer(regs)); 74 pr_cont("\n"); 75 show_regs(regs); 76 } 77 78 force_sig_fault(signo, code, (void __user *)addr, tsk); 79 } 80 81 static void do_trap_error(struct pt_regs *regs, int signo, int code, 82 unsigned long addr, const char *str) 83 { 84 if (user_mode(regs)) { 85 do_trap(regs, signo, code, addr, current); 86 } else { 87 if (!fixup_exception(regs)) 88 die(regs, str); 89 } 90 } 91 92 #define DO_ERROR_INFO(name, signo, code, str) \ 93 asmlinkage void name(struct pt_regs *regs) \ 94 { \ 95 do_trap_error(regs, signo, code, regs->sepc, "Oops - " str); \ 96 } 97 98 DO_ERROR_INFO(do_trap_unknown, 99 SIGILL, ILL_ILLTRP, "unknown exception"); 100 DO_ERROR_INFO(do_trap_insn_misaligned, 101 SIGBUS, BUS_ADRALN, "instruction address misaligned"); 102 DO_ERROR_INFO(do_trap_insn_fault, 103 SIGSEGV, SEGV_ACCERR, "instruction access fault"); 104 DO_ERROR_INFO(do_trap_insn_illegal, 105 SIGILL, ILL_ILLOPC, "illegal instruction"); 106 DO_ERROR_INFO(do_trap_load_misaligned, 107 SIGBUS, BUS_ADRALN, "load address misaligned"); 108 DO_ERROR_INFO(do_trap_load_fault, 109 SIGSEGV, SEGV_ACCERR, "load access fault"); 110 DO_ERROR_INFO(do_trap_store_misaligned, 111 SIGBUS, BUS_ADRALN, "store (or AMO) address misaligned"); 112 DO_ERROR_INFO(do_trap_store_fault, 113 SIGSEGV, SEGV_ACCERR, "store (or AMO) access fault"); 114 DO_ERROR_INFO(do_trap_ecall_u, 115 SIGILL, ILL_ILLTRP, "environment call from U-mode"); 116 DO_ERROR_INFO(do_trap_ecall_s, 117 SIGILL, ILL_ILLTRP, "environment call from S-mode"); 118 DO_ERROR_INFO(do_trap_ecall_m, 119 SIGILL, ILL_ILLTRP, "environment call from M-mode"); 120 121 #ifdef CONFIG_GENERIC_BUG 122 static inline unsigned long get_break_insn_length(unsigned long pc) 123 { 124 bug_insn_t insn; 125 126 if (probe_kernel_address((bug_insn_t *)pc, insn)) 127 return 0; 128 return (((insn & __INSN_LENGTH_MASK) == __INSN_LENGTH_32) ? 4UL : 2UL); 129 } 130 #endif /* CONFIG_GENERIC_BUG */ 131 132 asmlinkage void do_trap_break(struct pt_regs *regs) 133 { 134 #ifdef CONFIG_GENERIC_BUG 135 if (!user_mode(regs)) { 136 enum bug_trap_type type; 137 138 type = report_bug(regs->sepc, regs); 139 switch (type) { 140 case BUG_TRAP_TYPE_NONE: 141 break; 142 case BUG_TRAP_TYPE_WARN: 143 regs->sepc += get_break_insn_length(regs->sepc); 144 break; 145 case BUG_TRAP_TYPE_BUG: 146 die(regs, "Kernel BUG"); 147 } 148 } 149 #endif /* CONFIG_GENERIC_BUG */ 150 151 force_sig_fault(SIGTRAP, TRAP_BRKPT, (void __user *)(regs->sepc), current); 152 } 153 154 #ifdef CONFIG_GENERIC_BUG 155 int is_valid_bugaddr(unsigned long pc) 156 { 157 bug_insn_t insn; 158 159 if (pc < VMALLOC_START) 160 return 0; 161 if (probe_kernel_address((bug_insn_t *)pc, insn)) 162 return 0; 163 if ((insn & __INSN_LENGTH_MASK) == __INSN_LENGTH_32) 164 return (insn == __BUG_INSN_32); 165 else 166 return ((insn & __COMPRESSED_INSN_MASK) == __BUG_INSN_16); 167 } 168 #endif /* CONFIG_GENERIC_BUG */ 169 170 void __init trap_init(void) 171 { 172 /* 173 * Set sup0 scratch register to 0, indicating to exception vector 174 * that we are presently executing in the kernel 175 */ 176 csr_write(CSR_SSCRATCH, 0); 177 /* Set the exception vector address */ 178 csr_write(CSR_STVEC, &handle_exception); 179 /* Enable all interrupts */ 180 csr_write(CSR_SIE, -1); 181 } 182