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
get_trap_ip(struct pt_regs * regs)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
is_valid_bugaddr(unsigned long addr)40 int is_valid_bugaddr(unsigned long addr)
41 {
42 return 1;
43 }
44
do_report_trap(struct pt_regs * regs,int si_signo,int si_code,char * str)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
do_trap(struct pt_regs * regs,int si_signo,int si_code,char * str)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
do_per_trap(struct pt_regs * regs)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
default_trap_handler(struct pt_regs * regs)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
do_fp_trap(struct pt_regs * regs,__u32 fpc)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
translation_exception(struct pt_regs * regs)140 void translation_exception(struct pt_regs *regs)
141 {
142 /* May never happen. */
143 panic("Translation exception");
144 }
145
illegal_op(struct pt_regs * regs)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
vector_exception(struct pt_regs * regs)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
data_exception(struct pt_regs * regs)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
space_switch_exception(struct pt_regs * regs)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
monitor_event_exception(struct pt_regs * regs)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
kernel_stack_overflow(struct pt_regs * regs)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
test_monitor_call(void)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
trap_init(void)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
