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 int show_unhandled_signals = 1;
  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 static inline void report_user_fault(struct pt_regs *regs, int signr)
  39 {
  40         if ((task_pid_nr(current) > 1) && !show_unhandled_signals)
  41                 return;
  42         if (!unhandled_signal(current, signr))
  43                 return;
  44         if (!printk_ratelimit())
  45                 return;
  46         printk("User process fault: interruption code %04x ilc:%d ",
  47                regs->int_code & 0xffff, regs->int_code >> 17);
  48         print_vma_addr("in ", regs->psw.addr);
  49         printk("\n");
  50         show_regs(regs);
  51 }
  52
  53 int is_valid_bugaddr(unsigned long addr)
  54 {
  55         return 1;
  56 }
  57
  58 void do_report_trap(struct pt_regs *regs, int si_signo, int si_code, char *str)
  59 {
  60         siginfo_t info;
  61
  62         if (user_mode(regs)) {
  63                 info.si_signo = si_signo;
  64                 info.si_errno = 0;
  65                 info.si_code = si_code;
  66                 info.si_addr = get_trap_ip(regs);
  67                 force_sig_info(si_signo, &info, current);
  68                 report_user_fault(regs, si_signo);
  69         } else {
  70                 const struct exception_table_entry *fixup;
  71                 fixup = search_exception_tables(regs->psw.addr);
  72                 if (fixup)
  73                         regs->psw.addr = extable_fixup(fixup);
  74                 else {
  75                         enum bug_trap_type btt;
  76
  77                         btt = report_bug(regs->psw.addr, regs);
  78                         if (btt == BUG_TRAP_TYPE_WARN)
  79                                 return;
  80                         die(regs, str);
  81                 }
  82         }
  83 }
  84
  85 static void do_trap(struct pt_regs *regs, int si_signo, int si_code, char *str)
  86 {
  87         if (notify_die(DIE_TRAP, str, regs, 0,
  88                        regs->int_code, si_signo) == NOTIFY_STOP)
  89                 return;
  90         do_report_trap(regs, si_signo, si_code, str);
  91 }
  92 NOKPROBE_SYMBOL(do_trap);
  93
  94 void do_per_trap(struct pt_regs *regs)
  95 {
  96         siginfo_t info;
  97
  98         if (notify_die(DIE_SSTEP, "sstep", regs, 0, 0, SIGTRAP) == NOTIFY_STOP)
  99                 return;
 100         if (!current->ptrace)
 101                 return;
 102         info.si_signo = SIGTRAP;
 103         info.si_errno = 0;
 104         info.si_code = TRAP_HWBKPT;
 105         info.si_addr =
 106                 (void __force __user *) current->thread.per_event.address;
 107         force_sig_info(SIGTRAP, &info, current);
 108 }
 109 NOKPROBE_SYMBOL(do_per_trap);
 110
 111 void default_trap_handler(struct pt_regs *regs)
 112 {
 113         if (user_mode(regs)) {
 114                 report_user_fault(regs, SIGSEGV);
 115                 do_exit(SIGSEGV);
 116         } else
 117                 die(regs, "Unknown program exception");
 118 }
 119
 120 #define DO_ERROR_INFO(name, signr, sicode, str) \
 121 void name(struct pt_regs *regs)                 \
 122 {                                               \
 123         do_trap(regs, signr, sicode, str);      \
 124 }
 125
 126 DO_ERROR_INFO(addressing_exception, SIGILL, ILL_ILLADR,
 127               "addressing exception")
 128 DO_ERROR_INFO(execute_exception, SIGILL, ILL_ILLOPN,
 129               "execute exception")
 130 DO_ERROR_INFO(divide_exception, SIGFPE, FPE_INTDIV,
 131               "fixpoint divide exception")
 132 DO_ERROR_INFO(overflow_exception, SIGFPE, FPE_INTOVF,
 133               "fixpoint overflow exception")
 134 DO_ERROR_INFO(hfp_overflow_exception, SIGFPE, FPE_FLTOVF,
 135               "HFP overflow exception")
 136 DO_ERROR_INFO(hfp_underflow_exception, SIGFPE, FPE_FLTUND,
 137               "HFP underflow exception")
 138 DO_ERROR_INFO(hfp_significance_exception, SIGFPE, FPE_FLTRES,
 139               "HFP significance exception")
 140 DO_ERROR_INFO(hfp_divide_exception, SIGFPE, FPE_FLTDIV,
 141               "HFP divide exception")
 142 DO_ERROR_INFO(hfp_sqrt_exception, SIGFPE, FPE_FLTINV,
 143               "HFP square root exception")
 144 DO_ERROR_INFO(operand_exception, SIGILL, ILL_ILLOPN,
 145               "operand exception")
 146 DO_ERROR_INFO(privileged_op, SIGILL, ILL_PRVOPC,
 147               "privileged operation")
 148 DO_ERROR_INFO(special_op_exception, SIGILL, ILL_ILLOPN,
 149               "special operation exception")
 150 DO_ERROR_INFO(transaction_exception, SIGILL, ILL_ILLOPN,
 151               "transaction constraint exception")
 152
 153 static inline void do_fp_trap(struct pt_regs *regs, __u32 fpc)
 154 {
 155         int si_code = 0;
 156         /* FPC[2] is Data Exception Code */
 157         if ((fpc & 0x00000300) == 0) {
 158                 /* bits 6 and 7 of DXC are 0 iff IEEE exception */
 159                 if (fpc & 0x8000) /* invalid fp operation */
 160                         si_code = FPE_FLTINV;
 161                 else if (fpc & 0x4000) /* div by 0 */
 162                         si_code = FPE_FLTDIV;
 163                 else if (fpc & 0x2000) /* overflow */
 164                         si_code = FPE_FLTOVF;
 165                 else if (fpc & 0x1000) /* underflow */
 166                         si_code = FPE_FLTUND;
 167                 else if (fpc & 0x0800) /* inexact */
 168                         si_code = FPE_FLTRES;
 169         }
 170         do_trap(regs, SIGFPE, si_code, "floating point exception");
 171 }
 172
 173 void translation_exception(struct pt_regs *regs)
 174 {
 175         /* May never happen. */
 176         panic("Translation exception");
 177 }
 178
 179 void illegal_op(struct pt_regs *regs)
 180 {
 181         siginfo_t info;
 182         __u8 opcode[6];
 183         __u16 __user *location;
 184         int is_uprobe_insn = 0;
 185         int signal = 0;
 186
 187         location = get_trap_ip(regs);
 188
 189         if (user_mode(regs)) {
 190                 if (get_user(*((__u16 *) opcode), (__u16 __user *) location))
 191                         return;
 192                 if (*((__u16 *) opcode) == S390_BREAKPOINT_U16) {
 193                         if (current->ptrace) {
 194                                 info.si_signo = SIGTRAP;
 195                                 info.si_errno = 0;
 196                                 info.si_code = TRAP_BRKPT;
 197                                 info.si_addr = location;
 198                                 force_sig_info(SIGTRAP, &info, current);
 199                         } else
 200                                 signal = SIGILL;
 201 #ifdef CONFIG_UPROBES
 202                 } else if (*((__u16 *) opcode) == UPROBE_SWBP_INSN) {
 203                         is_uprobe_insn = 1;
 204 #endif
 205                 } else
 206                         signal = SIGILL;
 207         }
 208         /*
 209          * We got either an illegal op in kernel mode, or user space trapped
 210          * on a uprobes illegal instruction. See if kprobes or uprobes picks
 211          * it up. If not, SIGILL.
 212          */
 213         if (is_uprobe_insn || !user_mode(regs)) {
 214                 if (notify_die(DIE_BPT, "bpt", regs, 0,
 215                                3, SIGTRAP) != NOTIFY_STOP)
 216                         signal = SIGILL;
 217         }
 218         if (signal)
 219                 do_trap(regs, signal, ILL_ILLOPC, "illegal operation");
 220 }
 221 NOKPROBE_SYMBOL(illegal_op);
 222
 223 DO_ERROR_INFO(specification_exception, SIGILL, ILL_ILLOPN,
 224               "specification exception");
 225
 226 void vector_exception(struct pt_regs *regs)
 227 {
 228         int si_code, vic;
 229
 230         if (!MACHINE_HAS_VX) {
 231                 do_trap(regs, SIGILL, ILL_ILLOPN, "illegal operation");
 232                 return;
 233         }
 234
 235         /* get vector interrupt code from fpc */
 236         save_fpu_regs();
 237         vic = (current->thread.fpu.fpc & 0xf00) >> 8;
 238         switch (vic) {
 239         case 1: /* invalid vector operation */
 240                 si_code = FPE_FLTINV;
 241                 break;
 242         case 2: /* division by zero */
 243                 si_code = FPE_FLTDIV;
 244                 break;
 245         case 3: /* overflow */
 246                 si_code = FPE_FLTOVF;
 247                 break;
 248         case 4: /* underflow */
 249                 si_code = FPE_FLTUND;
 250                 break;
 251         case 5: /* inexact */
 252                 si_code = FPE_FLTRES;
 253                 break;
 254         default: /* unknown cause */
 255                 si_code = 0;
 256         }
 257         do_trap(regs, SIGFPE, si_code, "vector exception");
 258 }
 259
 260 void data_exception(struct pt_regs *regs)
 261 {
 262         int signal = 0;
 263
 264         save_fpu_regs();
 265         if (current->thread.fpu.fpc & FPC_DXC_MASK)
 266                 signal = SIGFPE;
 267         else
 268                 signal = SIGILL;
 269         if (signal == SIGFPE)
 270                 do_fp_trap(regs, current->thread.fpu.fpc);
 271         else if (signal)
 272                 do_trap(regs, signal, ILL_ILLOPN, "data exception");
 273 }
 274
 275 void space_switch_exception(struct pt_regs *regs)
 276 {
 277         /* Set user psw back to home space mode. */
 278         if (user_mode(regs))
 279                 regs->psw.mask |= PSW_ASC_HOME;
 280         /* Send SIGILL. */
 281         do_trap(regs, SIGILL, ILL_PRVOPC, "space switch event");
 282 }
 283
 284 void kernel_stack_overflow(struct pt_regs *regs)
 285 {
 286         bust_spinlocks(1);
 287         printk("Kernel stack overflow.\n");
 288         show_regs(regs);
 289         bust_spinlocks(0);
 290         panic("Corrupt kernel stack, can't continue.");
 291 }
 292 NOKPROBE_SYMBOL(kernel_stack_overflow);
 293
 294 void __init trap_init(void)
 295 {
 296         local_mcck_enable();
 297 }