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