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