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/kprobes.h> 16 #include <linux/mm.h> 17 #include <linux/module.h> 18 #include <linux/irq.h> 19 20 #include <asm/asm-prototypes.h> 21 #include <asm/bug.h> 22 #include <asm/processor.h> 23 #include <asm/ptrace.h> 24 #include <asm/csr.h> 25 26 int show_unhandled_signals = 1; 27 28 static DEFINE_SPINLOCK(die_lock); 29 30 void die(struct pt_regs *regs, const char *str) 31 { 32 static int die_counter; 33 int ret; 34 35 oops_enter(); 36 37 spin_lock_irq(&die_lock); 38 console_verbose(); 39 bust_spinlocks(1); 40 41 pr_emerg("%s [#%d]\n", str, ++die_counter); 42 print_modules(); 43 show_regs(regs); 44 45 ret = notify_die(DIE_OOPS, str, regs, 0, regs->cause, SIGSEGV); 46 47 bust_spinlocks(0); 48 add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE); 49 spin_unlock_irq(&die_lock); 50 oops_exit(); 51 52 if (in_interrupt()) 53 panic("Fatal exception in interrupt"); 54 if (panic_on_oops) 55 panic("Fatal exception"); 56 if (ret != NOTIFY_STOP) 57 make_task_dead(SIGSEGV); 58 } 59 60 void do_trap(struct pt_regs *regs, int signo, int code, unsigned long addr) 61 { 62 struct task_struct *tsk = current; 63 64 if (show_unhandled_signals && unhandled_signal(tsk, signo) 65 && printk_ratelimit()) { 66 pr_info("%s[%d]: unhandled signal %d code 0x%x at 0x" REG_FMT, 67 tsk->comm, task_pid_nr(tsk), signo, code, addr); 68 print_vma_addr(KERN_CONT " in ", instruction_pointer(regs)); 69 pr_cont("\n"); 70 __show_regs(regs); 71 } 72 73 force_sig_fault(signo, code, (void __user *)addr); 74 } 75 76 static void do_trap_error(struct pt_regs *regs, int signo, int code, 77 unsigned long addr, const char *str) 78 { 79 current->thread.bad_cause = regs->cause; 80 81 if (user_mode(regs)) { 82 do_trap(regs, signo, code, addr); 83 } else { 84 if (!fixup_exception(regs)) 85 die(regs, str); 86 } 87 } 88 89 #if defined (CONFIG_XIP_KERNEL) && defined (CONFIG_RISCV_ERRATA_ALTERNATIVE) 90 #define __trap_section __section(".xip.traps") 91 #else 92 #define __trap_section 93 #endif 94 #define DO_ERROR_INFO(name, signo, code, str) \ 95 asmlinkage __visible __trap_section void name(struct pt_regs *regs) \ 96 { \ 97 do_trap_error(regs, signo, code, regs->epc, "Oops - " str); \ 98 } 99 100 DO_ERROR_INFO(do_trap_unknown, 101 SIGILL, ILL_ILLTRP, "unknown exception"); 102 DO_ERROR_INFO(do_trap_insn_misaligned, 103 SIGBUS, BUS_ADRALN, "instruction address misaligned"); 104 DO_ERROR_INFO(do_trap_insn_fault, 105 SIGSEGV, SEGV_ACCERR, "instruction access fault"); 106 DO_ERROR_INFO(do_trap_insn_illegal, 107 SIGILL, ILL_ILLOPC, "illegal instruction"); 108 DO_ERROR_INFO(do_trap_load_fault, 109 SIGSEGV, SEGV_ACCERR, "load access fault"); 110 #ifndef CONFIG_RISCV_M_MODE 111 DO_ERROR_INFO(do_trap_load_misaligned, 112 SIGBUS, BUS_ADRALN, "Oops - load address misaligned"); 113 DO_ERROR_INFO(do_trap_store_misaligned, 114 SIGBUS, BUS_ADRALN, "Oops - store (or AMO) address misaligned"); 115 #else 116 int handle_misaligned_load(struct pt_regs *regs); 117 int handle_misaligned_store(struct pt_regs *regs); 118 119 asmlinkage void __trap_section do_trap_load_misaligned(struct pt_regs *regs) 120 { 121 if (!handle_misaligned_load(regs)) 122 return; 123 do_trap_error(regs, SIGBUS, BUS_ADRALN, regs->epc, 124 "Oops - load address misaligned"); 125 } 126 127 asmlinkage void __trap_section do_trap_store_misaligned(struct pt_regs *regs) 128 { 129 if (!handle_misaligned_store(regs)) 130 return; 131 do_trap_error(regs, SIGBUS, BUS_ADRALN, regs->epc, 132 "Oops - store (or AMO) address misaligned"); 133 } 134 #endif 135 DO_ERROR_INFO(do_trap_store_fault, 136 SIGSEGV, SEGV_ACCERR, "store (or AMO) access fault"); 137 DO_ERROR_INFO(do_trap_ecall_u, 138 SIGILL, ILL_ILLTRP, "environment call from U-mode"); 139 DO_ERROR_INFO(do_trap_ecall_s, 140 SIGILL, ILL_ILLTRP, "environment call from S-mode"); 141 DO_ERROR_INFO(do_trap_ecall_m, 142 SIGILL, ILL_ILLTRP, "environment call from M-mode"); 143 144 static inline unsigned long get_break_insn_length(unsigned long pc) 145 { 146 bug_insn_t insn; 147 148 if (get_kernel_nofault(insn, (bug_insn_t *)pc)) 149 return 0; 150 151 return GET_INSN_LENGTH(insn); 152 } 153 154 asmlinkage __visible __trap_section void do_trap_break(struct pt_regs *regs) 155 { 156 #ifdef CONFIG_KPROBES 157 if (kprobe_single_step_handler(regs)) 158 return; 159 160 if (kprobe_breakpoint_handler(regs)) 161 return; 162 #endif 163 #ifdef CONFIG_UPROBES 164 if (uprobe_single_step_handler(regs)) 165 return; 166 167 if (uprobe_breakpoint_handler(regs)) 168 return; 169 #endif 170 current->thread.bad_cause = regs->cause; 171 172 if (user_mode(regs)) 173 force_sig_fault(SIGTRAP, TRAP_BRKPT, (void __user *)regs->epc); 174 #ifdef CONFIG_KGDB 175 else if (notify_die(DIE_TRAP, "EBREAK", regs, 0, regs->cause, SIGTRAP) 176 == NOTIFY_STOP) 177 return; 178 #endif 179 else if (report_bug(regs->epc, regs) == BUG_TRAP_TYPE_WARN) 180 regs->epc += get_break_insn_length(regs->epc); 181 else 182 die(regs, "Kernel BUG"); 183 } 184 NOKPROBE_SYMBOL(do_trap_break); 185 186 #ifdef CONFIG_GENERIC_BUG 187 int is_valid_bugaddr(unsigned long pc) 188 { 189 bug_insn_t insn; 190 191 if (pc < VMALLOC_START) 192 return 0; 193 if (get_kernel_nofault(insn, (bug_insn_t *)pc)) 194 return 0; 195 if ((insn & __INSN_LENGTH_MASK) == __INSN_LENGTH_32) 196 return (insn == __BUG_INSN_32); 197 else 198 return ((insn & __COMPRESSED_INSN_MASK) == __BUG_INSN_16); 199 } 200 #endif /* CONFIG_GENERIC_BUG */ 201 202 #ifdef CONFIG_VMAP_STACK 203 static DEFINE_PER_CPU(unsigned long [OVERFLOW_STACK_SIZE/sizeof(long)], 204 overflow_stack)__aligned(16); 205 /* 206 * shadow stack, handled_ kernel_ stack_ overflow(in kernel/entry.S) is used 207 * to get per-cpu overflow stack(get_overflow_stack). 208 */ 209 long shadow_stack[SHADOW_OVERFLOW_STACK_SIZE/sizeof(long)]; 210 asmlinkage unsigned long get_overflow_stack(void) 211 { 212 return (unsigned long)this_cpu_ptr(overflow_stack) + 213 OVERFLOW_STACK_SIZE; 214 } 215 216 asmlinkage void handle_bad_stack(struct pt_regs *regs) 217 { 218 unsigned long tsk_stk = (unsigned long)current->stack; 219 unsigned long ovf_stk = (unsigned long)this_cpu_ptr(overflow_stack); 220 221 console_verbose(); 222 223 pr_emerg("Insufficient stack space to handle exception!\n"); 224 pr_emerg("Task stack: [0x%016lx..0x%016lx]\n", 225 tsk_stk, tsk_stk + THREAD_SIZE); 226 pr_emerg("Overflow stack: [0x%016lx..0x%016lx]\n", 227 ovf_stk, ovf_stk + OVERFLOW_STACK_SIZE); 228 229 __show_regs(regs); 230 panic("Kernel stack overflow"); 231 232 for (;;) 233 wait_for_interrupt(); 234 } 235 #endif 236