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 #include <linux/kexec.h> 20 21 #include <asm/asm-prototypes.h> 22 #include <asm/bug.h> 23 #include <asm/csr.h> 24 #include <asm/processor.h> 25 #include <asm/ptrace.h> 26 #include <asm/thread_info.h> 27 28 int show_unhandled_signals = 1; 29 30 static DEFINE_SPINLOCK(die_lock); 31 32 void die(struct pt_regs *regs, const char *str) 33 { 34 static int die_counter; 35 int ret; 36 37 oops_enter(); 38 39 spin_lock_irq(&die_lock); 40 console_verbose(); 41 bust_spinlocks(1); 42 43 pr_emerg("%s [#%d]\n", str, ++die_counter); 44 print_modules(); 45 show_regs(regs); 46 47 ret = notify_die(DIE_OOPS, str, regs, 0, regs->cause, SIGSEGV); 48 49 if (regs && kexec_should_crash(current)) 50 crash_kexec(regs); 51 52 bust_spinlocks(0); 53 add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE); 54 spin_unlock_irq(&die_lock); 55 oops_exit(); 56 57 if (in_interrupt()) 58 panic("Fatal exception in interrupt"); 59 if (panic_on_oops) 60 panic("Fatal exception"); 61 if (ret != NOTIFY_STOP) 62 make_task_dead(SIGSEGV); 63 } 64 65 void do_trap(struct pt_regs *regs, int signo, int code, unsigned long addr) 66 { 67 struct task_struct *tsk = current; 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); 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 current->thread.bad_cause = regs->cause; 85 86 if (user_mode(regs)) { 87 do_trap(regs, signo, code, addr); 88 } else { 89 if (!fixup_exception(regs)) 90 die(regs, str); 91 } 92 } 93 94 #if defined(CONFIG_XIP_KERNEL) && defined(CONFIG_RISCV_ALTERNATIVE) 95 #define __trap_section __section(".xip.traps") 96 #else 97 #define __trap_section 98 #endif 99 #define DO_ERROR_INFO(name, signo, code, str) \ 100 asmlinkage __visible __trap_section void name(struct pt_regs *regs) \ 101 { \ 102 do_trap_error(regs, signo, code, regs->epc, "Oops - " str); \ 103 } 104 105 DO_ERROR_INFO(do_trap_unknown, 106 SIGILL, ILL_ILLTRP, "unknown exception"); 107 DO_ERROR_INFO(do_trap_insn_misaligned, 108 SIGBUS, BUS_ADRALN, "instruction address misaligned"); 109 DO_ERROR_INFO(do_trap_insn_fault, 110 SIGSEGV, SEGV_ACCERR, "instruction access fault"); 111 DO_ERROR_INFO(do_trap_insn_illegal, 112 SIGILL, ILL_ILLOPC, "illegal instruction"); 113 DO_ERROR_INFO(do_trap_load_fault, 114 SIGSEGV, SEGV_ACCERR, "load access fault"); 115 #ifndef CONFIG_RISCV_M_MODE 116 DO_ERROR_INFO(do_trap_load_misaligned, 117 SIGBUS, BUS_ADRALN, "Oops - load address misaligned"); 118 DO_ERROR_INFO(do_trap_store_misaligned, 119 SIGBUS, BUS_ADRALN, "Oops - store (or AMO) address misaligned"); 120 #else 121 int handle_misaligned_load(struct pt_regs *regs); 122 int handle_misaligned_store(struct pt_regs *regs); 123 124 asmlinkage void __trap_section do_trap_load_misaligned(struct pt_regs *regs) 125 { 126 if (!handle_misaligned_load(regs)) 127 return; 128 do_trap_error(regs, SIGBUS, BUS_ADRALN, regs->epc, 129 "Oops - load address misaligned"); 130 } 131 132 asmlinkage void __trap_section do_trap_store_misaligned(struct pt_regs *regs) 133 { 134 if (!handle_misaligned_store(regs)) 135 return; 136 do_trap_error(regs, SIGBUS, BUS_ADRALN, regs->epc, 137 "Oops - store (or AMO) address misaligned"); 138 } 139 #endif 140 DO_ERROR_INFO(do_trap_store_fault, 141 SIGSEGV, SEGV_ACCERR, "store (or AMO) access fault"); 142 DO_ERROR_INFO(do_trap_ecall_u, 143 SIGILL, ILL_ILLTRP, "environment call from U-mode"); 144 DO_ERROR_INFO(do_trap_ecall_s, 145 SIGILL, ILL_ILLTRP, "environment call from S-mode"); 146 DO_ERROR_INFO(do_trap_ecall_m, 147 SIGILL, ILL_ILLTRP, "environment call from M-mode"); 148 149 static inline unsigned long get_break_insn_length(unsigned long pc) 150 { 151 bug_insn_t insn; 152 153 if (get_kernel_nofault(insn, (bug_insn_t *)pc)) 154 return 0; 155 156 return GET_INSN_LENGTH(insn); 157 } 158 159 asmlinkage __visible __trap_section void do_trap_break(struct pt_regs *regs) 160 { 161 #ifdef CONFIG_KPROBES 162 if (kprobe_single_step_handler(regs)) 163 return; 164 165 if (kprobe_breakpoint_handler(regs)) 166 return; 167 #endif 168 #ifdef CONFIG_UPROBES 169 if (uprobe_single_step_handler(regs)) 170 return; 171 172 if (uprobe_breakpoint_handler(regs)) 173 return; 174 #endif 175 current->thread.bad_cause = regs->cause; 176 177 if (user_mode(regs)) 178 force_sig_fault(SIGTRAP, TRAP_BRKPT, (void __user *)regs->epc); 179 #ifdef CONFIG_KGDB 180 else if (notify_die(DIE_TRAP, "EBREAK", regs, 0, regs->cause, SIGTRAP) 181 == NOTIFY_STOP) 182 return; 183 #endif 184 else if (report_bug(regs->epc, regs) == BUG_TRAP_TYPE_WARN) 185 regs->epc += get_break_insn_length(regs->epc); 186 else 187 die(regs, "Kernel BUG"); 188 } 189 NOKPROBE_SYMBOL(do_trap_break); 190 191 #ifdef CONFIG_GENERIC_BUG 192 int is_valid_bugaddr(unsigned long pc) 193 { 194 bug_insn_t insn; 195 196 if (pc < VMALLOC_START) 197 return 0; 198 if (get_kernel_nofault(insn, (bug_insn_t *)pc)) 199 return 0; 200 if ((insn & __INSN_LENGTH_MASK) == __INSN_LENGTH_32) 201 return (insn == __BUG_INSN_32); 202 else 203 return ((insn & __COMPRESSED_INSN_MASK) == __BUG_INSN_16); 204 } 205 #endif /* CONFIG_GENERIC_BUG */ 206 207 #ifdef CONFIG_VMAP_STACK 208 static DEFINE_PER_CPU(unsigned long [OVERFLOW_STACK_SIZE/sizeof(long)], 209 overflow_stack)__aligned(16); 210 /* 211 * shadow stack, handled_ kernel_ stack_ overflow(in kernel/entry.S) is used 212 * to get per-cpu overflow stack(get_overflow_stack). 213 */ 214 long shadow_stack[SHADOW_OVERFLOW_STACK_SIZE/sizeof(long)]; 215 asmlinkage unsigned long get_overflow_stack(void) 216 { 217 return (unsigned long)this_cpu_ptr(overflow_stack) + 218 OVERFLOW_STACK_SIZE; 219 } 220 221 asmlinkage void handle_bad_stack(struct pt_regs *regs) 222 { 223 unsigned long tsk_stk = (unsigned long)current->stack; 224 unsigned long ovf_stk = (unsigned long)this_cpu_ptr(overflow_stack); 225 226 console_verbose(); 227 228 pr_emerg("Insufficient stack space to handle exception!\n"); 229 pr_emerg("Task stack: [0x%016lx..0x%016lx]\n", 230 tsk_stk, tsk_stk + THREAD_SIZE); 231 pr_emerg("Overflow stack: [0x%016lx..0x%016lx]\n", 232 ovf_stk, ovf_stk + OVERFLOW_STACK_SIZE); 233 234 __show_regs(regs); 235 panic("Kernel stack overflow"); 236 237 for (;;) 238 wait_for_interrupt(); 239 } 240 #endif 241