1 // SPDX-License-Identifier: GPL-2.0
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),
8 * Derived from "arch/i386/kernel/traps.c"
9 * Copyright (C) 1991, 1992 Linus Torvalds
13 * 'Traps.c' handles hardware traps and faults after we have saved some
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>
23 #include <linux/slab.h>
24 #include <linux/uaccess.h>
25 #include <linux/cpu.h>
26 #include <asm/fpu/api.h>
29 static inline void __user *get_trap_ip(struct pt_regs *regs)
31 unsigned long address;
33 if (regs->int_code & 0x200)
34 address = *(unsigned long *)(current->thread.trap_tdb + 24);
36 address = regs->psw.addr;
37 return (void __user *) (address - (regs->int_code >> 16));
40 int is_valid_bugaddr(unsigned long addr)
45 void do_report_trap(struct pt_regs *regs, int si_signo, int si_code, char *str)
47 if (user_mode(regs)) {
48 force_sig_fault(si_signo, si_code, get_trap_ip(regs), current);
49 report_user_fault(regs, si_signo, 0);
51 const struct exception_table_entry *fixup;
52 fixup = search_exception_tables(regs->psw.addr);
54 regs->psw.addr = extable_fixup(fixup);
56 enum bug_trap_type btt;
58 btt = report_bug(regs->psw.addr, regs);
59 if (btt == BUG_TRAP_TYPE_WARN)
66 static void do_trap(struct pt_regs *regs, int si_signo, int si_code, char *str)
68 if (notify_die(DIE_TRAP, str, regs, 0,
69 regs->int_code, si_signo) == NOTIFY_STOP)
71 do_report_trap(regs, si_signo, si_code, str);
73 NOKPROBE_SYMBOL(do_trap);
75 void do_per_trap(struct pt_regs *regs)
77 if (notify_die(DIE_SSTEP, "sstep", regs, 0, 0, SIGTRAP) == NOTIFY_STOP)
81 force_sig_fault(SIGTRAP, TRAP_HWBKPT,
82 (void __force __user *) current->thread.per_event.address, current);
84 NOKPROBE_SYMBOL(do_per_trap);
86 void default_trap_handler(struct pt_regs *regs)
88 if (user_mode(regs)) {
89 report_user_fault(regs, SIGSEGV, 0);
92 die(regs, "Unknown program exception");
95 #define DO_ERROR_INFO(name, signr, sicode, str) \
96 void name(struct pt_regs *regs) \
98 do_trap(regs, signr, sicode, str); \
101 DO_ERROR_INFO(addressing_exception, SIGILL, ILL_ILLADR,
102 "addressing exception")
103 DO_ERROR_INFO(execute_exception, SIGILL, ILL_ILLOPN,
105 DO_ERROR_INFO(divide_exception, SIGFPE, FPE_INTDIV,
106 "fixpoint divide exception")
107 DO_ERROR_INFO(overflow_exception, SIGFPE, FPE_INTOVF,
108 "fixpoint overflow exception")
109 DO_ERROR_INFO(hfp_overflow_exception, SIGFPE, FPE_FLTOVF,
110 "HFP overflow exception")
111 DO_ERROR_INFO(hfp_underflow_exception, SIGFPE, FPE_FLTUND,
112 "HFP underflow exception")
113 DO_ERROR_INFO(hfp_significance_exception, SIGFPE, FPE_FLTRES,
114 "HFP significance exception")
115 DO_ERROR_INFO(hfp_divide_exception, SIGFPE, FPE_FLTDIV,
116 "HFP divide exception")
117 DO_ERROR_INFO(hfp_sqrt_exception, SIGFPE, FPE_FLTINV,
118 "HFP square root exception")
119 DO_ERROR_INFO(operand_exception, SIGILL, ILL_ILLOPN,
121 DO_ERROR_INFO(privileged_op, SIGILL, ILL_PRVOPC,
122 "privileged operation")
123 DO_ERROR_INFO(special_op_exception, SIGILL, ILL_ILLOPN,
124 "special operation exception")
125 DO_ERROR_INFO(transaction_exception, SIGILL, ILL_ILLOPN,
126 "transaction constraint exception")
128 static inline void do_fp_trap(struct pt_regs *regs, __u32 fpc)
131 /* FPC[2] is Data Exception Code */
132 if ((fpc & 0x00000300) == 0) {
133 /* bits 6 and 7 of DXC are 0 iff IEEE exception */
134 if (fpc & 0x8000) /* invalid fp operation */
135 si_code = FPE_FLTINV;
136 else if (fpc & 0x4000) /* div by 0 */
137 si_code = FPE_FLTDIV;
138 else if (fpc & 0x2000) /* overflow */
139 si_code = FPE_FLTOVF;
140 else if (fpc & 0x1000) /* underflow */
141 si_code = FPE_FLTUND;
142 else if (fpc & 0x0800) /* inexact */
143 si_code = FPE_FLTRES;
145 do_trap(regs, SIGFPE, si_code, "floating point exception");
148 void translation_exception(struct pt_regs *regs)
150 /* May never happen. */
151 panic("Translation exception");
154 void illegal_op(struct pt_regs *regs)
157 __u16 __user *location;
158 int is_uprobe_insn = 0;
161 location = get_trap_ip(regs);
163 if (user_mode(regs)) {
164 if (get_user(*((__u16 *) opcode), (__u16 __user *) location))
166 if (*((__u16 *) opcode) == S390_BREAKPOINT_U16) {
168 force_sig_fault(SIGTRAP, TRAP_BRKPT, location, current);
171 #ifdef CONFIG_UPROBES
172 } else if (*((__u16 *) opcode) == UPROBE_SWBP_INSN) {
179 * We got either an illegal op in kernel mode, or user space trapped
180 * on a uprobes illegal instruction. See if kprobes or uprobes picks
181 * it up. If not, SIGILL.
183 if (is_uprobe_insn || !user_mode(regs)) {
184 if (notify_die(DIE_BPT, "bpt", regs, 0,
185 3, SIGTRAP) != NOTIFY_STOP)
189 do_trap(regs, signal, ILL_ILLOPC, "illegal operation");
191 NOKPROBE_SYMBOL(illegal_op);
193 DO_ERROR_INFO(specification_exception, SIGILL, ILL_ILLOPN,
194 "specification exception");
196 void vector_exception(struct pt_regs *regs)
200 if (!MACHINE_HAS_VX) {
201 do_trap(regs, SIGILL, ILL_ILLOPN, "illegal operation");
205 /* get vector interrupt code from fpc */
207 vic = (current->thread.fpu.fpc & 0xf00) >> 8;
209 case 1: /* invalid vector operation */
210 si_code = FPE_FLTINV;
212 case 2: /* division by zero */
213 si_code = FPE_FLTDIV;
215 case 3: /* overflow */
216 si_code = FPE_FLTOVF;
218 case 4: /* underflow */
219 si_code = FPE_FLTUND;
221 case 5: /* inexact */
222 si_code = FPE_FLTRES;
224 default: /* unknown cause */
227 do_trap(regs, SIGFPE, si_code, "vector exception");
230 void data_exception(struct pt_regs *regs)
235 if (current->thread.fpu.fpc & FPC_DXC_MASK)
239 if (signal == SIGFPE)
240 do_fp_trap(regs, current->thread.fpu.fpc);
242 do_trap(regs, signal, ILL_ILLOPN, "data exception");
245 void space_switch_exception(struct pt_regs *regs)
247 /* Set user psw back to home space mode. */
249 regs->psw.mask |= PSW_ASC_HOME;
251 do_trap(regs, SIGILL, ILL_PRVOPC, "space switch event");
254 void kernel_stack_overflow(struct pt_regs *regs)
257 printk("Kernel stack overflow.\n");
260 panic("Corrupt kernel stack, can't continue.");
262 NOKPROBE_SYMBOL(kernel_stack_overflow);
264 void __init trap_init(void)