1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * S390 version 4 * Copyright IBM Corp. 1999, 2000 5 * Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com), 6 * Denis Joseph Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com), 7 * 8 * Derived from "arch/i386/kernel/traps.c" 9 * Copyright (C) 1991, 1992 Linus Torvalds 10 */ 11 12 /* 13 * 'Traps.c' handles hardware traps and faults after we have saved some 14 * state in 'asm.s'. 15 */ 16 #include <linux/kprobes.h> 17 #include <linux/kdebug.h> 18 #include <linux/extable.h> 19 #include <linux/ptrace.h> 20 #include <linux/sched.h> 21 #include <linux/sched/debug.h> 22 #include <linux/mm.h> 23 #include <linux/slab.h> 24 #include <linux/uaccess.h> 25 #include <linux/cpu.h> 26 #include <asm/fpu/api.h> 27 #include "entry.h" 28 29 static inline void __user *get_trap_ip(struct pt_regs *regs) 30 { 31 unsigned long address; 32 33 if (regs->int_code & 0x200) 34 address = *(unsigned long *)(current->thread.trap_tdb + 24); 35 else 36 address = regs->psw.addr; 37 return (void __user *) (address - (regs->int_code >> 16)); 38 } 39 40 int is_valid_bugaddr(unsigned long addr) 41 { 42 return 1; 43 } 44 45 void do_report_trap(struct pt_regs *regs, int si_signo, int si_code, char *str) 46 { 47 if (user_mode(regs)) { 48 force_sig_fault(si_signo, si_code, get_trap_ip(regs)); 49 report_user_fault(regs, si_signo, 0); 50 } else { 51 const struct exception_table_entry *fixup; 52 fixup = s390_search_extables(regs->psw.addr); 53 if (!fixup || !ex_handle(fixup, regs)) 54 die(regs, str); 55 } 56 } 57 58 static void do_trap(struct pt_regs *regs, int si_signo, int si_code, char *str) 59 { 60 if (notify_die(DIE_TRAP, str, regs, 0, 61 regs->int_code, si_signo) == NOTIFY_STOP) 62 return; 63 do_report_trap(regs, si_signo, si_code, str); 64 } 65 NOKPROBE_SYMBOL(do_trap); 66 67 void do_per_trap(struct pt_regs *regs) 68 { 69 if (notify_die(DIE_SSTEP, "sstep", regs, 0, 0, SIGTRAP) == NOTIFY_STOP) 70 return; 71 if (!current->ptrace) 72 return; 73 force_sig_fault(SIGTRAP, TRAP_HWBKPT, 74 (void __force __user *) current->thread.per_event.address); 75 } 76 NOKPROBE_SYMBOL(do_per_trap); 77 78 void default_trap_handler(struct pt_regs *regs) 79 { 80 if (user_mode(regs)) { 81 report_user_fault(regs, SIGSEGV, 0); 82 do_exit(SIGSEGV); 83 } else 84 die(regs, "Unknown program exception"); 85 } 86 87 #define DO_ERROR_INFO(name, signr, sicode, str) \ 88 void name(struct pt_regs *regs) \ 89 { \ 90 do_trap(regs, signr, sicode, str); \ 91 } 92 93 DO_ERROR_INFO(addressing_exception, SIGILL, ILL_ILLADR, 94 "addressing exception") 95 DO_ERROR_INFO(execute_exception, SIGILL, ILL_ILLOPN, 96 "execute exception") 97 DO_ERROR_INFO(divide_exception, SIGFPE, FPE_INTDIV, 98 "fixpoint divide exception") 99 DO_ERROR_INFO(overflow_exception, SIGFPE, FPE_INTOVF, 100 "fixpoint overflow exception") 101 DO_ERROR_INFO(hfp_overflow_exception, SIGFPE, FPE_FLTOVF, 102 "HFP overflow exception") 103 DO_ERROR_INFO(hfp_underflow_exception, SIGFPE, FPE_FLTUND, 104 "HFP underflow exception") 105 DO_ERROR_INFO(hfp_significance_exception, SIGFPE, FPE_FLTRES, 106 "HFP significance exception") 107 DO_ERROR_INFO(hfp_divide_exception, SIGFPE, FPE_FLTDIV, 108 "HFP divide exception") 109 DO_ERROR_INFO(hfp_sqrt_exception, SIGFPE, FPE_FLTINV, 110 "HFP square root exception") 111 DO_ERROR_INFO(operand_exception, SIGILL, ILL_ILLOPN, 112 "operand exception") 113 DO_ERROR_INFO(privileged_op, SIGILL, ILL_PRVOPC, 114 "privileged operation") 115 DO_ERROR_INFO(special_op_exception, SIGILL, ILL_ILLOPN, 116 "special operation exception") 117 DO_ERROR_INFO(transaction_exception, SIGILL, ILL_ILLOPN, 118 "transaction constraint exception") 119 120 static inline void do_fp_trap(struct pt_regs *regs, __u32 fpc) 121 { 122 int si_code = 0; 123 /* FPC[2] is Data Exception Code */ 124 if ((fpc & 0x00000300) == 0) { 125 /* bits 6 and 7 of DXC are 0 iff IEEE exception */ 126 if (fpc & 0x8000) /* invalid fp operation */ 127 si_code = FPE_FLTINV; 128 else if (fpc & 0x4000) /* div by 0 */ 129 si_code = FPE_FLTDIV; 130 else if (fpc & 0x2000) /* overflow */ 131 si_code = FPE_FLTOVF; 132 else if (fpc & 0x1000) /* underflow */ 133 si_code = FPE_FLTUND; 134 else if (fpc & 0x0800) /* inexact */ 135 si_code = FPE_FLTRES; 136 } 137 do_trap(regs, SIGFPE, si_code, "floating point exception"); 138 } 139 140 void translation_exception(struct pt_regs *regs) 141 { 142 /* May never happen. */ 143 panic("Translation exception"); 144 } 145 146 void illegal_op(struct pt_regs *regs) 147 { 148 __u8 opcode[6]; 149 __u16 __user *location; 150 int is_uprobe_insn = 0; 151 int signal = 0; 152 153 location = get_trap_ip(regs); 154 155 if (user_mode(regs)) { 156 if (get_user(*((__u16 *) opcode), (__u16 __user *) location)) 157 return; 158 if (*((__u16 *) opcode) == S390_BREAKPOINT_U16) { 159 if (current->ptrace) 160 force_sig_fault(SIGTRAP, TRAP_BRKPT, location); 161 else 162 signal = SIGILL; 163 #ifdef CONFIG_UPROBES 164 } else if (*((__u16 *) opcode) == UPROBE_SWBP_INSN) { 165 is_uprobe_insn = 1; 166 #endif 167 } else 168 signal = SIGILL; 169 } 170 /* 171 * We got either an illegal op in kernel mode, or user space trapped 172 * on a uprobes illegal instruction. See if kprobes or uprobes picks 173 * it up. If not, SIGILL. 174 */ 175 if (is_uprobe_insn || !user_mode(regs)) { 176 if (notify_die(DIE_BPT, "bpt", regs, 0, 177 3, SIGTRAP) != NOTIFY_STOP) 178 signal = SIGILL; 179 } 180 if (signal) 181 do_trap(regs, signal, ILL_ILLOPC, "illegal operation"); 182 } 183 NOKPROBE_SYMBOL(illegal_op); 184 185 DO_ERROR_INFO(specification_exception, SIGILL, ILL_ILLOPN, 186 "specification exception"); 187 188 void vector_exception(struct pt_regs *regs) 189 { 190 int si_code, vic; 191 192 if (!MACHINE_HAS_VX) { 193 do_trap(regs, SIGILL, ILL_ILLOPN, "illegal operation"); 194 return; 195 } 196 197 /* get vector interrupt code from fpc */ 198 save_fpu_regs(); 199 vic = (current->thread.fpu.fpc & 0xf00) >> 8; 200 switch (vic) { 201 case 1: /* invalid vector operation */ 202 si_code = FPE_FLTINV; 203 break; 204 case 2: /* division by zero */ 205 si_code = FPE_FLTDIV; 206 break; 207 case 3: /* overflow */ 208 si_code = FPE_FLTOVF; 209 break; 210 case 4: /* underflow */ 211 si_code = FPE_FLTUND; 212 break; 213 case 5: /* inexact */ 214 si_code = FPE_FLTRES; 215 break; 216 default: /* unknown cause */ 217 si_code = 0; 218 } 219 do_trap(regs, SIGFPE, si_code, "vector exception"); 220 } 221 222 void data_exception(struct pt_regs *regs) 223 { 224 save_fpu_regs(); 225 if (current->thread.fpu.fpc & FPC_DXC_MASK) 226 do_fp_trap(regs, current->thread.fpu.fpc); 227 else 228 do_trap(regs, SIGILL, ILL_ILLOPN, "data exception"); 229 } 230 231 void space_switch_exception(struct pt_regs *regs) 232 { 233 /* Set user psw back to home space mode. */ 234 if (user_mode(regs)) 235 regs->psw.mask |= PSW_ASC_HOME; 236 /* Send SIGILL. */ 237 do_trap(regs, SIGILL, ILL_PRVOPC, "space switch event"); 238 } 239 240 void monitor_event_exception(struct pt_regs *regs) 241 { 242 const struct exception_table_entry *fixup; 243 244 if (user_mode(regs)) 245 return; 246 247 switch (report_bug(regs->psw.addr - (regs->int_code >> 16), regs)) { 248 case BUG_TRAP_TYPE_NONE: 249 fixup = s390_search_extables(regs->psw.addr); 250 if (fixup) 251 ex_handle(fixup, regs); 252 break; 253 case BUG_TRAP_TYPE_WARN: 254 break; 255 case BUG_TRAP_TYPE_BUG: 256 die(regs, "monitor event"); 257 break; 258 } 259 } 260 261 void kernel_stack_overflow(struct pt_regs *regs) 262 { 263 bust_spinlocks(1); 264 printk("Kernel stack overflow.\n"); 265 show_regs(regs); 266 bust_spinlocks(0); 267 panic("Corrupt kernel stack, can't continue."); 268 } 269 NOKPROBE_SYMBOL(kernel_stack_overflow); 270 271 static void __init test_monitor_call(void) 272 { 273 int val = 1; 274 275 asm volatile( 276 " mc 0,0\n" 277 "0: xgr %0,%0\n" 278 "1:\n" 279 EX_TABLE(0b,1b) 280 : "+d" (val)); 281 if (!val) 282 panic("Monitor call doesn't work!\n"); 283 } 284 285 void __init trap_init(void) 286 { 287 sort_extable(__start_dma_ex_table, __stop_dma_ex_table); 288 local_mcck_enable(); 289 test_monitor_call(); 290 } 291