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 <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 }