1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Copyright (C) 2012 Regents of the University of California 4 */ 5 6 #include <linux/kernel.h> 7 #include <linux/init.h> 8 #include <linux/sched.h> 9 #include <linux/sched/debug.h> 10 #include <linux/sched/signal.h> 11 #include <linux/signal.h> 12 #include <linux/kdebug.h> 13 #include <linux/uaccess.h> 14 #include <linux/mm.h> 15 #include <linux/module.h> 16 #include <linux/irq.h> 17 18 #include <asm/processor.h> 19 #include <asm/ptrace.h> 20 #include <asm/csr.h> 21 22 int show_unhandled_signals = 1; 23 24 extern asmlinkage void handle_exception(void); 25 26 static DEFINE_SPINLOCK(die_lock); 27 28 void die(struct pt_regs *regs, const char *str) 29 { 30 static int die_counter; 31 int ret; 32 33 oops_enter(); 34 35 spin_lock_irq(&die_lock); 36 console_verbose(); 37 bust_spinlocks(1); 38 39 pr_emerg("%s [#%d]\n", str, ++die_counter); 40 print_modules(); 41 show_regs(regs); 42 43 ret = notify_die(DIE_OOPS, str, regs, 0, regs->scause, SIGSEGV); 44 45 bust_spinlocks(0); 46 add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE); 47 spin_unlock_irq(&die_lock); 48 oops_exit(); 49 50 if (in_interrupt()) 51 panic("Fatal exception in interrupt"); 52 if (panic_on_oops) 53 panic("Fatal exception"); 54 if (ret != NOTIFY_STOP) 55 do_exit(SIGSEGV); 56 } 57 58 void do_trap(struct pt_regs *regs, int signo, int code, 59 unsigned long addr, struct task_struct *tsk) 60 { 61 if (show_unhandled_signals && unhandled_signal(tsk, signo) 62 && printk_ratelimit()) { 63 pr_info("%s[%d]: unhandled signal %d code 0x%x at 0x" REG_FMT, 64 tsk->comm, task_pid_nr(tsk), signo, code, addr); 65 print_vma_addr(KERN_CONT " in ", instruction_pointer(regs)); 66 pr_cont("\n"); 67 show_regs(regs); 68 } 69 70 force_sig_fault(signo, code, (void __user *)addr, tsk); 71 } 72 73 static void do_trap_error(struct pt_regs *regs, int signo, int code, 74 unsigned long addr, const char *str) 75 { 76 if (user_mode(regs)) { 77 do_trap(regs, signo, code, addr, current); 78 } else { 79 if (!fixup_exception(regs)) 80 die(regs, str); 81 } 82 } 83 84 #define DO_ERROR_INFO(name, signo, code, str) \ 85 asmlinkage void name(struct pt_regs *regs) \ 86 { \ 87 do_trap_error(regs, signo, code, regs->sepc, "Oops - " str); \ 88 } 89 90 DO_ERROR_INFO(do_trap_unknown, 91 SIGILL, ILL_ILLTRP, "unknown exception"); 92 DO_ERROR_INFO(do_trap_insn_misaligned, 93 SIGBUS, BUS_ADRALN, "instruction address misaligned"); 94 DO_ERROR_INFO(do_trap_insn_fault, 95 SIGSEGV, SEGV_ACCERR, "instruction access fault"); 96 DO_ERROR_INFO(do_trap_insn_illegal, 97 SIGILL, ILL_ILLOPC, "illegal instruction"); 98 DO_ERROR_INFO(do_trap_load_misaligned, 99 SIGBUS, BUS_ADRALN, "load address misaligned"); 100 DO_ERROR_INFO(do_trap_load_fault, 101 SIGSEGV, SEGV_ACCERR, "load access fault"); 102 DO_ERROR_INFO(do_trap_store_misaligned, 103 SIGBUS, BUS_ADRALN, "store (or AMO) address misaligned"); 104 DO_ERROR_INFO(do_trap_store_fault, 105 SIGSEGV, SEGV_ACCERR, "store (or AMO) access fault"); 106 DO_ERROR_INFO(do_trap_ecall_u, 107 SIGILL, ILL_ILLTRP, "environment call from U-mode"); 108 DO_ERROR_INFO(do_trap_ecall_s, 109 SIGILL, ILL_ILLTRP, "environment call from S-mode"); 110 DO_ERROR_INFO(do_trap_ecall_m, 111 SIGILL, ILL_ILLTRP, "environment call from M-mode"); 112 113 #ifdef CONFIG_GENERIC_BUG 114 static inline unsigned long get_break_insn_length(unsigned long pc) 115 { 116 bug_insn_t insn; 117 118 if (probe_kernel_address((bug_insn_t *)pc, insn)) 119 return 0; 120 return (((insn & __INSN_LENGTH_MASK) == __INSN_LENGTH_32) ? 4UL : 2UL); 121 } 122 #endif /* CONFIG_GENERIC_BUG */ 123 124 asmlinkage void do_trap_break(struct pt_regs *regs) 125 { 126 #ifdef CONFIG_GENERIC_BUG 127 if (!user_mode(regs)) { 128 enum bug_trap_type type; 129 130 type = report_bug(regs->sepc, regs); 131 switch (type) { 132 case BUG_TRAP_TYPE_NONE: 133 break; 134 case BUG_TRAP_TYPE_WARN: 135 regs->sepc += get_break_insn_length(regs->sepc); 136 break; 137 case BUG_TRAP_TYPE_BUG: 138 die(regs, "Kernel BUG"); 139 } 140 } 141 #endif /* CONFIG_GENERIC_BUG */ 142 143 force_sig_fault(SIGTRAP, TRAP_BRKPT, (void __user *)(regs->sepc), current); 144 } 145 146 #ifdef CONFIG_GENERIC_BUG 147 int is_valid_bugaddr(unsigned long pc) 148 { 149 bug_insn_t insn; 150 151 if (pc < VMALLOC_START) 152 return 0; 153 if (probe_kernel_address((bug_insn_t *)pc, insn)) 154 return 0; 155 if ((insn & __INSN_LENGTH_MASK) == __INSN_LENGTH_32) 156 return (insn == __BUG_INSN_32); 157 else 158 return ((insn & __COMPRESSED_INSN_MASK) == __BUG_INSN_16); 159 } 160 #endif /* CONFIG_GENERIC_BUG */ 161 162 void __init trap_init(void) 163 { 164 /* 165 * Set sup0 scratch register to 0, indicating to exception vector 166 * that we are presently executing in the kernel 167 */ 168 csr_write(CSR_SSCRATCH, 0); 169 /* Set the exception vector address */ 170 csr_write(CSR_STVEC, &handle_exception); 171 /* Enable all interrupts */ 172 csr_write(CSR_SIE, -1); 173 } 174