1 /* 2 * S390 version 3 * Copyright IBM Corp. 1999, 2000 4 * Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com), 5 * Denis Joseph Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com), 6 * 7 * Derived from "arch/i386/kernel/traps.c" 8 * Copyright (C) 1991, 1992 Linus Torvalds 9 */ 10 11 /* 12 * 'Traps.c' handles hardware traps and faults after we have saved some 13 * state in 'asm.s'. 14 */ 15 #include <linux/kprobes.h> 16 #include <linux/kdebug.h> 17 #include <linux/extable.h> 18 #include <linux/ptrace.h> 19 #include <linux/sched.h> 20 #include <linux/sched/debug.h> 21 #include <linux/mm.h> 22 #include <linux/slab.h> 23 #include <linux/uaccess.h> 24 #include <linux/cpu.h> 25 #include <asm/fpu/api.h> 26 #include "entry.h" 27 28 static inline void __user *get_trap_ip(struct pt_regs *regs) 29 { 30 unsigned long address; 31 32 if (regs->int_code & 0x200) 33 address = *(unsigned long *)(current->thread.trap_tdb + 24); 34 else 35 address = regs->psw.addr; 36 return (void __user *) (address - (regs->int_code >> 16)); 37 } 38 39 int is_valid_bugaddr(unsigned long addr) 40 { 41 return 1; 42 } 43 44 void do_report_trap(struct pt_regs *regs, int si_signo, int si_code, char *str) 45 { 46 siginfo_t info; 47 48 if (user_mode(regs)) { 49 info.si_signo = si_signo; 50 info.si_errno = 0; 51 info.si_code = si_code; 52 info.si_addr = get_trap_ip(regs); 53 force_sig_info(si_signo, &info, current); 54 report_user_fault(regs, si_signo, 0); 55 } else { 56 const struct exception_table_entry *fixup; 57 fixup = search_exception_tables(regs->psw.addr); 58 if (fixup) 59 regs->psw.addr = extable_fixup(fixup); 60 else { 61 enum bug_trap_type btt; 62 63 btt = report_bug(regs->psw.addr, regs); 64 if (btt == BUG_TRAP_TYPE_WARN) 65 return; 66 die(regs, str); 67 } 68 } 69 } 70 71 static void do_trap(struct pt_regs *regs, int si_signo, int si_code, char *str) 72 { 73 if (notify_die(DIE_TRAP, str, regs, 0, 74 regs->int_code, si_signo) == NOTIFY_STOP) 75 return; 76 do_report_trap(regs, si_signo, si_code, str); 77 } 78 NOKPROBE_SYMBOL(do_trap); 79 80 void do_per_trap(struct pt_regs *regs) 81 { 82 siginfo_t info; 83 84 if (notify_die(DIE_SSTEP, "sstep", regs, 0, 0, SIGTRAP) == NOTIFY_STOP) 85 return; 86 if (!current->ptrace) 87 return; 88 info.si_signo = SIGTRAP; 89 info.si_errno = 0; 90 info.si_code = TRAP_HWBKPT; 91 info.si_addr = 92 (void __force __user *) current->thread.per_event.address; 93 force_sig_info(SIGTRAP, &info, current); 94 } 95 NOKPROBE_SYMBOL(do_per_trap); 96 97 void default_trap_handler(struct pt_regs *regs) 98 { 99 if (user_mode(regs)) { 100 report_user_fault(regs, SIGSEGV, 0); 101 do_exit(SIGSEGV); 102 } else 103 die(regs, "Unknown program exception"); 104 } 105 106 #define DO_ERROR_INFO(name, signr, sicode, str) \ 107 void name(struct pt_regs *regs) \ 108 { \ 109 do_trap(regs, signr, sicode, str); \ 110 } 111 112 DO_ERROR_INFO(addressing_exception, SIGILL, ILL_ILLADR, 113 "addressing exception") 114 DO_ERROR_INFO(execute_exception, SIGILL, ILL_ILLOPN, 115 "execute exception") 116 DO_ERROR_INFO(divide_exception, SIGFPE, FPE_INTDIV, 117 "fixpoint divide exception") 118 DO_ERROR_INFO(overflow_exception, SIGFPE, FPE_INTOVF, 119 "fixpoint overflow exception") 120 DO_ERROR_INFO(hfp_overflow_exception, SIGFPE, FPE_FLTOVF, 121 "HFP overflow exception") 122 DO_ERROR_INFO(hfp_underflow_exception, SIGFPE, FPE_FLTUND, 123 "HFP underflow exception") 124 DO_ERROR_INFO(hfp_significance_exception, SIGFPE, FPE_FLTRES, 125 "HFP significance exception") 126 DO_ERROR_INFO(hfp_divide_exception, SIGFPE, FPE_FLTDIV, 127 "HFP divide exception") 128 DO_ERROR_INFO(hfp_sqrt_exception, SIGFPE, FPE_FLTINV, 129 "HFP square root exception") 130 DO_ERROR_INFO(operand_exception, SIGILL, ILL_ILLOPN, 131 "operand exception") 132 DO_ERROR_INFO(privileged_op, SIGILL, ILL_PRVOPC, 133 "privileged operation") 134 DO_ERROR_INFO(special_op_exception, SIGILL, ILL_ILLOPN, 135 "special operation exception") 136 DO_ERROR_INFO(transaction_exception, SIGILL, ILL_ILLOPN, 137 "transaction constraint exception") 138 139 static inline void do_fp_trap(struct pt_regs *regs, __u32 fpc) 140 { 141 int si_code = 0; 142 /* FPC[2] is Data Exception Code */ 143 if ((fpc & 0x00000300) == 0) { 144 /* bits 6 and 7 of DXC are 0 iff IEEE exception */ 145 if (fpc & 0x8000) /* invalid fp operation */ 146 si_code = FPE_FLTINV; 147 else if (fpc & 0x4000) /* div by 0 */ 148 si_code = FPE_FLTDIV; 149 else if (fpc & 0x2000) /* overflow */ 150 si_code = FPE_FLTOVF; 151 else if (fpc & 0x1000) /* underflow */ 152 si_code = FPE_FLTUND; 153 else if (fpc & 0x0800) /* inexact */ 154 si_code = FPE_FLTRES; 155 } 156 do_trap(regs, SIGFPE, si_code, "floating point exception"); 157 } 158 159 void translation_exception(struct pt_regs *regs) 160 { 161 /* May never happen. */ 162 panic("Translation exception"); 163 } 164 165 void illegal_op(struct pt_regs *regs) 166 { 167 siginfo_t info; 168 __u8 opcode[6]; 169 __u16 __user *location; 170 int is_uprobe_insn = 0; 171 int signal = 0; 172 173 location = get_trap_ip(regs); 174 175 if (user_mode(regs)) { 176 if (get_user(*((__u16 *) opcode), (__u16 __user *) location)) 177 return; 178 if (*((__u16 *) opcode) == S390_BREAKPOINT_U16) { 179 if (current->ptrace) { 180 info.si_signo = SIGTRAP; 181 info.si_errno = 0; 182 info.si_code = TRAP_BRKPT; 183 info.si_addr = location; 184 force_sig_info(SIGTRAP, &info, current); 185 } else 186 signal = SIGILL; 187 #ifdef CONFIG_UPROBES 188 } else if (*((__u16 *) opcode) == UPROBE_SWBP_INSN) { 189 is_uprobe_insn = 1; 190 #endif 191 } else 192 signal = SIGILL; 193 } 194 /* 195 * We got either an illegal op in kernel mode, or user space trapped 196 * on a uprobes illegal instruction. See if kprobes or uprobes picks 197 * it up. If not, SIGILL. 198 */ 199 if (is_uprobe_insn || !user_mode(regs)) { 200 if (notify_die(DIE_BPT, "bpt", regs, 0, 201 3, SIGTRAP) != NOTIFY_STOP) 202 signal = SIGILL; 203 } 204 if (signal) 205 do_trap(regs, signal, ILL_ILLOPC, "illegal operation"); 206 } 207 NOKPROBE_SYMBOL(illegal_op); 208 209 DO_ERROR_INFO(specification_exception, SIGILL, ILL_ILLOPN, 210 "specification exception"); 211 212 void vector_exception(struct pt_regs *regs) 213 { 214 int si_code, vic; 215 216 if (!MACHINE_HAS_VX) { 217 do_trap(regs, SIGILL, ILL_ILLOPN, "illegal operation"); 218 return; 219 } 220 221 /* get vector interrupt code from fpc */ 222 save_fpu_regs(); 223 vic = (current->thread.fpu.fpc & 0xf00) >> 8; 224 switch (vic) { 225 case 1: /* invalid vector operation */ 226 si_code = FPE_FLTINV; 227 break; 228 case 2: /* division by zero */ 229 si_code = FPE_FLTDIV; 230 break; 231 case 3: /* overflow */ 232 si_code = FPE_FLTOVF; 233 break; 234 case 4: /* underflow */ 235 si_code = FPE_FLTUND; 236 break; 237 case 5: /* inexact */ 238 si_code = FPE_FLTRES; 239 break; 240 default: /* unknown cause */ 241 si_code = 0; 242 } 243 do_trap(regs, SIGFPE, si_code, "vector exception"); 244 } 245 246 void data_exception(struct pt_regs *regs) 247 { 248 int signal = 0; 249 250 save_fpu_regs(); 251 if (current->thread.fpu.fpc & FPC_DXC_MASK) 252 signal = SIGFPE; 253 else 254 signal = SIGILL; 255 if (signal == SIGFPE) 256 do_fp_trap(regs, current->thread.fpu.fpc); 257 else if (signal) 258 do_trap(regs, signal, ILL_ILLOPN, "data exception"); 259 } 260 261 void space_switch_exception(struct pt_regs *regs) 262 { 263 /* Set user psw back to home space mode. */ 264 if (user_mode(regs)) 265 regs->psw.mask |= PSW_ASC_HOME; 266 /* Send SIGILL. */ 267 do_trap(regs, SIGILL, ILL_PRVOPC, "space switch event"); 268 } 269 270 void kernel_stack_overflow(struct pt_regs *regs) 271 { 272 bust_spinlocks(1); 273 printk("Kernel stack overflow.\n"); 274 show_regs(regs); 275 bust_spinlocks(0); 276 panic("Corrupt kernel stack, can't continue."); 277 } 278 NOKPROBE_SYMBOL(kernel_stack_overflow); 279 280 void __init trap_init(void) 281 { 282 local_mcck_enable(); 283 } 284