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