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 static inline void do_trap_siginfo(int signo, int code, 67 unsigned long addr, struct task_struct *tsk) 68 { 69 siginfo_t info; 70 71 info.si_signo = signo; 72 info.si_errno = 0; 73 info.si_code = code; 74 info.si_addr = (void __user *)addr; 75 force_sig_info(signo, &info, tsk); 76 } 77 78 void do_trap(struct pt_regs *regs, int signo, int code, 79 unsigned long addr, struct task_struct *tsk) 80 { 81 if (show_unhandled_signals && unhandled_signal(tsk, signo) 82 && printk_ratelimit()) { 83 pr_info("%s[%d]: unhandled signal %d code 0x%x at 0x" REG_FMT, 84 tsk->comm, task_pid_nr(tsk), signo, code, addr); 85 print_vma_addr(KERN_CONT " in ", GET_IP(regs)); 86 pr_cont("\n"); 87 show_regs(regs); 88 } 89 90 do_trap_siginfo(signo, code, addr, tsk); 91 } 92 93 static void do_trap_error(struct pt_regs *regs, int signo, int code, 94 unsigned long addr, const char *str) 95 { 96 if (user_mode(regs)) { 97 do_trap(regs, signo, code, addr, current); 98 } else { 99 if (!fixup_exception(regs)) 100 die(regs, str); 101 } 102 } 103 104 #define DO_ERROR_INFO(name, signo, code, str) \ 105 asmlinkage void name(struct pt_regs *regs) \ 106 { \ 107 do_trap_error(regs, signo, code, regs->sepc, "Oops - " str); \ 108 } 109 110 DO_ERROR_INFO(do_trap_unknown, 111 SIGILL, ILL_ILLTRP, "unknown exception"); 112 DO_ERROR_INFO(do_trap_insn_misaligned, 113 SIGBUS, BUS_ADRALN, "instruction address misaligned"); 114 DO_ERROR_INFO(do_trap_insn_fault, 115 SIGSEGV, SEGV_ACCERR, "instruction access fault"); 116 DO_ERROR_INFO(do_trap_insn_illegal, 117 SIGILL, ILL_ILLOPC, "illegal instruction"); 118 DO_ERROR_INFO(do_trap_load_misaligned, 119 SIGBUS, BUS_ADRALN, "load address misaligned"); 120 DO_ERROR_INFO(do_trap_load_fault, 121 SIGSEGV, SEGV_ACCERR, "load access fault"); 122 DO_ERROR_INFO(do_trap_store_misaligned, 123 SIGBUS, BUS_ADRALN, "store (or AMO) address misaligned"); 124 DO_ERROR_INFO(do_trap_store_fault, 125 SIGSEGV, SEGV_ACCERR, "store (or AMO) access fault"); 126 DO_ERROR_INFO(do_trap_ecall_u, 127 SIGILL, ILL_ILLTRP, "environment call from U-mode"); 128 DO_ERROR_INFO(do_trap_ecall_s, 129 SIGILL, ILL_ILLTRP, "environment call from S-mode"); 130 DO_ERROR_INFO(do_trap_ecall_m, 131 SIGILL, ILL_ILLTRP, "environment call from M-mode"); 132 133 asmlinkage void do_trap_break(struct pt_regs *regs) 134 { 135 #ifdef CONFIG_GENERIC_BUG 136 if (!user_mode(regs)) { 137 enum bug_trap_type type; 138 139 type = report_bug(regs->sepc, regs); 140 switch (type) { 141 case BUG_TRAP_TYPE_NONE: 142 break; 143 case BUG_TRAP_TYPE_WARN: 144 regs->sepc += sizeof(bug_insn_t); 145 return; 146 case BUG_TRAP_TYPE_BUG: 147 die(regs, "Kernel BUG"); 148 } 149 } 150 #endif /* CONFIG_GENERIC_BUG */ 151 152 do_trap_siginfo(SIGTRAP, TRAP_BRKPT, regs->sepc, current); 153 regs->sepc += 0x4; 154 } 155 156 #ifdef CONFIG_GENERIC_BUG 157 int is_valid_bugaddr(unsigned long pc) 158 { 159 bug_insn_t insn; 160 161 if (pc < PAGE_OFFSET) 162 return 0; 163 if (probe_kernel_address((bug_insn_t __user *)pc, insn)) 164 return 0; 165 return (insn == __BUG_INSN); 166 } 167 #endif /* CONFIG_GENERIC_BUG */ 168 169 void __init trap_init(void) 170 { 171 /* 172 * Set sup0 scratch register to 0, indicating to exception vector 173 * that we are presently executing in the kernel 174 */ 175 csr_write(sscratch, 0); 176 /* Set the exception vector address */ 177 csr_write(stvec, &handle_exception); 178 /* Enable all interrupts */ 179 csr_write(sie, -1); 180 } 181