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