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)
49 if (user_mode(regs)) {
50 info.si_signo = si_signo;
52 info.si_code = si_code;
53 info.si_addr = get_trap_ip(regs);
54 force_sig_info(si_signo, &info, current);
55 report_user_fault(regs, si_signo, 0);
57 const struct exception_table_entry *fixup;
58 fixup = search_exception_tables(regs->psw.addr);
60 regs->psw.addr = extable_fixup(fixup);
62 enum bug_trap_type btt;
64 btt = report_bug(regs->psw.addr, regs);
65 if (btt == BUG_TRAP_TYPE_WARN)
72 static void do_trap(struct pt_regs *regs, int si_signo, int si_code, char *str)
74 if (notify_die(DIE_TRAP, str, regs, 0,
75 regs->int_code, si_signo) == NOTIFY_STOP)
77 do_report_trap(regs, si_signo, si_code, str);
79 NOKPROBE_SYMBOL(do_trap);
81 void do_per_trap(struct pt_regs *regs)
85 if (notify_die(DIE_SSTEP, "sstep", regs, 0, 0, SIGTRAP) == NOTIFY_STOP)
89 info.si_signo = SIGTRAP;
91 info.si_code = TRAP_HWBKPT;
93 (void __force __user *) current->thread.per_event.address;
94 force_sig_info(SIGTRAP, &info, current);
96 NOKPROBE_SYMBOL(do_per_trap);
98 void default_trap_handler(struct pt_regs *regs)
100 if (user_mode(regs)) {
101 report_user_fault(regs, SIGSEGV, 0);
104 die(regs, "Unknown program exception");
107 #define DO_ERROR_INFO(name, signr, sicode, str) \
108 void name(struct pt_regs *regs) \
110 do_trap(regs, signr, sicode, str); \
113 DO_ERROR_INFO(addressing_exception, SIGILL, ILL_ILLADR,
114 "addressing exception")
115 DO_ERROR_INFO(execute_exception, SIGILL, ILL_ILLOPN,
117 DO_ERROR_INFO(divide_exception, SIGFPE, FPE_INTDIV,
118 "fixpoint divide exception")
119 DO_ERROR_INFO(overflow_exception, SIGFPE, FPE_INTOVF,
120 "fixpoint overflow exception")
121 DO_ERROR_INFO(hfp_overflow_exception, SIGFPE, FPE_FLTOVF,
122 "HFP overflow exception")
123 DO_ERROR_INFO(hfp_underflow_exception, SIGFPE, FPE_FLTUND,
124 "HFP underflow exception")
125 DO_ERROR_INFO(hfp_significance_exception, SIGFPE, FPE_FLTRES,
126 "HFP significance exception")
127 DO_ERROR_INFO(hfp_divide_exception, SIGFPE, FPE_FLTDIV,
128 "HFP divide exception")
129 DO_ERROR_INFO(hfp_sqrt_exception, SIGFPE, FPE_FLTINV,
130 "HFP square root exception")
131 DO_ERROR_INFO(operand_exception, SIGILL, ILL_ILLOPN,
133 DO_ERROR_INFO(privileged_op, SIGILL, ILL_PRVOPC,
134 "privileged operation")
135 DO_ERROR_INFO(special_op_exception, SIGILL, ILL_ILLOPN,
136 "special operation exception")
137 DO_ERROR_INFO(transaction_exception, SIGILL, ILL_ILLOPN,
138 "transaction constraint exception")
140 static inline void do_fp_trap(struct pt_regs *regs, __u32 fpc)
143 /* FPC[2] is Data Exception Code */
144 if ((fpc & 0x00000300) == 0) {
145 /* bits 6 and 7 of DXC are 0 iff IEEE exception */
146 if (fpc & 0x8000) /* invalid fp operation */
147 si_code = FPE_FLTINV;
148 else if (fpc & 0x4000) /* div by 0 */
149 si_code = FPE_FLTDIV;
150 else if (fpc & 0x2000) /* overflow */
151 si_code = FPE_FLTOVF;
152 else if (fpc & 0x1000) /* underflow */
153 si_code = FPE_FLTUND;
154 else if (fpc & 0x0800) /* inexact */
155 si_code = FPE_FLTRES;
157 do_trap(regs, SIGFPE, si_code, "floating point exception");
160 void translation_exception(struct pt_regs *regs)
162 /* May never happen. */
163 panic("Translation exception");
166 void illegal_op(struct pt_regs *regs)
170 __u16 __user *location;
171 int is_uprobe_insn = 0;
174 location = get_trap_ip(regs);
176 if (user_mode(regs)) {
177 if (get_user(*((__u16 *) opcode), (__u16 __user *) location))
179 if (*((__u16 *) opcode) == S390_BREAKPOINT_U16) {
180 if (current->ptrace) {
181 info.si_signo = SIGTRAP;
183 info.si_code = TRAP_BRKPT;
184 info.si_addr = location;
185 force_sig_info(SIGTRAP, &info, current);
188 #ifdef CONFIG_UPROBES
189 } else if (*((__u16 *) opcode) == UPROBE_SWBP_INSN) {
196 * We got either an illegal op in kernel mode, or user space trapped
197 * on a uprobes illegal instruction. See if kprobes or uprobes picks
198 * it up. If not, SIGILL.
200 if (is_uprobe_insn || !user_mode(regs)) {
201 if (notify_die(DIE_BPT, "bpt", regs, 0,
202 3, SIGTRAP) != NOTIFY_STOP)
206 do_trap(regs, signal, ILL_ILLOPC, "illegal operation");
208 NOKPROBE_SYMBOL(illegal_op);
210 DO_ERROR_INFO(specification_exception, SIGILL, ILL_ILLOPN,
211 "specification exception");
213 void vector_exception(struct pt_regs *regs)
217 if (!MACHINE_HAS_VX) {
218 do_trap(regs, SIGILL, ILL_ILLOPN, "illegal operation");
222 /* get vector interrupt code from fpc */
224 vic = (current->thread.fpu.fpc & 0xf00) >> 8;
226 case 1: /* invalid vector operation */
227 si_code = FPE_FLTINV;
229 case 2: /* division by zero */
230 si_code = FPE_FLTDIV;
232 case 3: /* overflow */
233 si_code = FPE_FLTOVF;
235 case 4: /* underflow */
236 si_code = FPE_FLTUND;
238 case 5: /* inexact */
239 si_code = FPE_FLTRES;
241 default: /* unknown cause */
244 do_trap(regs, SIGFPE, si_code, "vector exception");
247 void data_exception(struct pt_regs *regs)
252 if (current->thread.fpu.fpc & FPC_DXC_MASK)
256 if (signal == SIGFPE)
257 do_fp_trap(regs, current->thread.fpu.fpc);
259 do_trap(regs, signal, ILL_ILLOPN, "data exception");
262 void space_switch_exception(struct pt_regs *regs)
264 /* Set user psw back to home space mode. */
266 regs->psw.mask |= PSW_ASC_HOME;
268 do_trap(regs, SIGILL, ILL_PRVOPC, "space switch event");
271 void kernel_stack_overflow(struct pt_regs *regs)
274 printk("Kernel stack overflow.\n");
277 panic("Corrupt kernel stack, can't continue.");
279 NOKPROBE_SYMBOL(kernel_stack_overflow);
281 void __init trap_init(void)