arch/s390/kernel/traps.c

   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 <linux/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 }