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 "asm/irqflags.h"
17 #include "asm/ptrace.h"
18 #include <linux/kprobes.h>
19 #include <linux/kdebug.h>
20 #include <linux/randomize_kstack.h>
21 #include <linux/extable.h>
22 #include <linux/ptrace.h>
23 #include <linux/sched.h>
24 #include <linux/sched/debug.h>
26 #include <linux/slab.h>
27 #include <linux/uaccess.h>
28 #include <linux/cpu.h>
29 #include <linux/entry-common.h>
30 #include <asm/asm-extable.h>
31 #include <asm/fpu/api.h>
32 #include <asm/vtime.h>
35 static inline void __user *get_trap_ip(struct pt_regs *regs)
37 unsigned long address;
39 if (regs->int_code & 0x200)
40 address = current->thread.trap_tdb.data[3];
42 address = regs->psw.addr;
43 return (void __user *) (address - (regs->int_code >> 16));
46 int is_valid_bugaddr(unsigned long addr)
51 void do_report_trap(struct pt_regs *regs, int si_signo, int si_code, char *str)
53 if (user_mode(regs)) {
54 force_sig_fault(si_signo, si_code, get_trap_ip(regs));
55 report_user_fault(regs, si_signo, 0);
57 if (!fixup_exception(regs))
62 static void do_trap(struct pt_regs *regs, int si_signo, int si_code, char *str)
64 if (notify_die(DIE_TRAP, str, regs, 0,
65 regs->int_code, si_signo) == NOTIFY_STOP)
67 do_report_trap(regs, si_signo, si_code, str);
69 NOKPROBE_SYMBOL(do_trap);
71 void do_per_trap(struct pt_regs *regs)
73 if (notify_die(DIE_SSTEP, "sstep", regs, 0, 0, SIGTRAP) == NOTIFY_STOP)
77 force_sig_fault(SIGTRAP, TRAP_HWBKPT,
78 (void __force __user *) current->thread.per_event.address);
80 NOKPROBE_SYMBOL(do_per_trap);
82 static void default_trap_handler(struct pt_regs *regs)
84 if (user_mode(regs)) {
85 report_user_fault(regs, SIGSEGV, 0);
86 force_exit_sig(SIGSEGV);
88 die(regs, "Unknown program exception");
91 #define DO_ERROR_INFO(name, signr, sicode, str) \
92 static void name(struct pt_regs *regs) \
94 do_trap(regs, signr, sicode, str); \
97 DO_ERROR_INFO(addressing_exception, SIGILL, ILL_ILLADR,
98 "addressing exception")
99 DO_ERROR_INFO(execute_exception, SIGILL, ILL_ILLOPN,
101 DO_ERROR_INFO(divide_exception, SIGFPE, FPE_INTDIV,
102 "fixpoint divide exception")
103 DO_ERROR_INFO(overflow_exception, SIGFPE, FPE_INTOVF,
104 "fixpoint overflow exception")
105 DO_ERROR_INFO(hfp_overflow_exception, SIGFPE, FPE_FLTOVF,
106 "HFP overflow exception")
107 DO_ERROR_INFO(hfp_underflow_exception, SIGFPE, FPE_FLTUND,
108 "HFP underflow exception")
109 DO_ERROR_INFO(hfp_significance_exception, SIGFPE, FPE_FLTRES,
110 "HFP significance exception")
111 DO_ERROR_INFO(hfp_divide_exception, SIGFPE, FPE_FLTDIV,
112 "HFP divide exception")
113 DO_ERROR_INFO(hfp_sqrt_exception, SIGFPE, FPE_FLTINV,
114 "HFP square root exception")
115 DO_ERROR_INFO(operand_exception, SIGILL, ILL_ILLOPN,
117 DO_ERROR_INFO(privileged_op, SIGILL, ILL_PRVOPC,
118 "privileged operation")
119 DO_ERROR_INFO(special_op_exception, SIGILL, ILL_ILLOPN,
120 "special operation exception")
121 DO_ERROR_INFO(transaction_exception, SIGILL, ILL_ILLOPN,
122 "transaction constraint exception")
124 static inline void do_fp_trap(struct pt_regs *regs, __u32 fpc)
127 /* FPC[2] is Data Exception Code */
128 if ((fpc & 0x00000300) == 0) {
129 /* bits 6 and 7 of DXC are 0 iff IEEE exception */
130 if (fpc & 0x8000) /* invalid fp operation */
131 si_code = FPE_FLTINV;
132 else if (fpc & 0x4000) /* div by 0 */
133 si_code = FPE_FLTDIV;
134 else if (fpc & 0x2000) /* overflow */
135 si_code = FPE_FLTOVF;
136 else if (fpc & 0x1000) /* underflow */
137 si_code = FPE_FLTUND;
138 else if (fpc & 0x0800) /* inexact */
139 si_code = FPE_FLTRES;
141 do_trap(regs, SIGFPE, si_code, "floating point exception");
144 static void translation_specification_exception(struct pt_regs *regs)
146 /* May never happen. */
147 panic("Translation-Specification Exception");
150 static void illegal_op(struct pt_regs *regs)
153 __u16 __user *location;
154 int is_uprobe_insn = 0;
157 location = get_trap_ip(regs);
159 if (user_mode(regs)) {
160 if (get_user(*((__u16 *) opcode), (__u16 __user *) location))
162 if (*((__u16 *) opcode) == S390_BREAKPOINT_U16) {
164 force_sig_fault(SIGTRAP, TRAP_BRKPT, location);
167 #ifdef CONFIG_UPROBES
168 } else if (*((__u16 *) opcode) == UPROBE_SWBP_INSN) {
175 * We got either an illegal op in kernel mode, or user space trapped
176 * on a uprobes illegal instruction. See if kprobes or uprobes picks
177 * it up. If not, SIGILL.
179 if (is_uprobe_insn || !user_mode(regs)) {
180 if (notify_die(DIE_BPT, "bpt", regs, 0,
181 3, SIGTRAP) != NOTIFY_STOP)
185 do_trap(regs, signal, ILL_ILLOPC, "illegal operation");
187 NOKPROBE_SYMBOL(illegal_op);
189 DO_ERROR_INFO(specification_exception, SIGILL, ILL_ILLOPN,
190 "specification exception");
192 static void vector_exception(struct pt_regs *regs)
196 if (!MACHINE_HAS_VX) {
197 do_trap(regs, SIGILL, ILL_ILLOPN, "illegal operation");
201 /* get vector interrupt code from fpc */
203 vic = (current->thread.fpu.fpc & 0xf00) >> 8;
205 case 1: /* invalid vector operation */
206 si_code = FPE_FLTINV;
208 case 2: /* division by zero */
209 si_code = FPE_FLTDIV;
211 case 3: /* overflow */
212 si_code = FPE_FLTOVF;
214 case 4: /* underflow */
215 si_code = FPE_FLTUND;
217 case 5: /* inexact */
218 si_code = FPE_FLTRES;
220 default: /* unknown cause */
223 do_trap(regs, SIGFPE, si_code, "vector exception");
226 static void data_exception(struct pt_regs *regs)
229 if (current->thread.fpu.fpc & FPC_DXC_MASK)
230 do_fp_trap(regs, current->thread.fpu.fpc);
232 do_trap(regs, SIGILL, ILL_ILLOPN, "data exception");
235 static void space_switch_exception(struct pt_regs *regs)
237 /* Set user psw back to home space mode. */
239 regs->psw.mask |= PSW_ASC_HOME;
241 do_trap(regs, SIGILL, ILL_PRVOPC, "space switch event");
244 static void monitor_event_exception(struct pt_regs *regs)
249 switch (report_bug(regs->psw.addr - (regs->int_code >> 16), regs)) {
250 case BUG_TRAP_TYPE_NONE:
251 fixup_exception(regs);
253 case BUG_TRAP_TYPE_WARN:
255 case BUG_TRAP_TYPE_BUG:
256 die(regs, "monitor event");
261 void kernel_stack_overflow(struct pt_regs *regs)
264 printk("Kernel stack overflow.\n");
267 panic("Corrupt kernel stack, can't continue.");
269 NOKPROBE_SYMBOL(kernel_stack_overflow);
271 static void __init test_monitor_call(void)
275 if (!IS_ENABLED(CONFIG_BUG))
284 panic("Monitor call doesn't work!\n");
287 void __init trap_init(void)
293 static void (*pgm_check_table[128])(struct pt_regs *regs);
295 void noinstr __do_pgm_check(struct pt_regs *regs)
298 irqentry_state_t state;
300 regs->int_code = S390_lowcore.pgm_int_code;
301 regs->int_parm_long = S390_lowcore.trans_exc_code;
303 state = irqentry_enter(regs);
305 if (user_mode(regs)) {
307 if (!static_branch_likely(&cpu_has_bear)) {
308 if (regs->last_break < 4096)
309 regs->last_break = 1;
311 current->thread.last_break = regs->last_break;
314 if (S390_lowcore.pgm_code & 0x0200) {
315 /* transaction abort */
316 current->thread.trap_tdb = S390_lowcore.pgm_tdb;
319 if (S390_lowcore.pgm_code & PGM_INT_CODE_PER) {
320 if (user_mode(regs)) {
321 struct per_event *ev = ¤t->thread.per_event;
323 set_thread_flag(TIF_PER_TRAP);
324 ev->address = S390_lowcore.per_address;
325 ev->cause = S390_lowcore.per_code_combined;
326 ev->paid = S390_lowcore.per_access_id;
328 /* PER event in kernel is kprobes */
329 __arch_local_irq_ssm(regs->psw.mask & ~PSW_MASK_PER);
335 if (!irqs_disabled_flags(regs->psw.mask))
337 __arch_local_irq_ssm(regs->psw.mask & ~PSW_MASK_PER);
339 trapnr = regs->int_code & PGM_INT_CODE_MASK;
341 pgm_check_table[trapnr](regs);
344 irqentry_exit(regs, state);
348 * The program check table contains exactly 128 (0x00-0x7f) entries. Each
349 * line defines the function to be called corresponding to the program check
352 static void (*pgm_check_table[128])(struct pt_regs *regs) = {
353 [0x00] = default_trap_handler,
355 [0x02] = privileged_op,
356 [0x03] = execute_exception,
357 [0x04] = do_protection_exception,
358 [0x05] = addressing_exception,
359 [0x06] = specification_exception,
360 [0x07] = data_exception,
361 [0x08] = overflow_exception,
362 [0x09] = divide_exception,
363 [0x0a] = overflow_exception,
364 [0x0b] = divide_exception,
365 [0x0c] = hfp_overflow_exception,
366 [0x0d] = hfp_underflow_exception,
367 [0x0e] = hfp_significance_exception,
368 [0x0f] = hfp_divide_exception,
369 [0x10] = do_dat_exception,
370 [0x11] = do_dat_exception,
371 [0x12] = translation_specification_exception,
372 [0x13] = special_op_exception,
373 [0x14] = default_trap_handler,
374 [0x15] = operand_exception,
375 [0x16] = default_trap_handler,
376 [0x17] = default_trap_handler,
377 [0x18] = transaction_exception,
378 [0x19] = default_trap_handler,
379 [0x1a] = default_trap_handler,
380 [0x1b] = vector_exception,
381 [0x1c] = space_switch_exception,
382 [0x1d] = hfp_sqrt_exception,
383 [0x1e ... 0x37] = default_trap_handler,
384 [0x38] = do_dat_exception,
385 [0x39] = do_dat_exception,
386 [0x3a] = do_dat_exception,
387 [0x3b] = do_dat_exception,
388 [0x3c] = default_trap_handler,
389 [0x3d] = do_secure_storage_access,
390 [0x3e] = do_non_secure_storage_access,
391 [0x3f] = do_secure_storage_violation,
392 [0x40] = monitor_event_exception,
393 [0x41 ... 0x7f] = default_trap_handler,
396 #define COND_TRAP(x) asm( \
397 ".weak " __stringify(x) "\n\t" \
398 ".set " __stringify(x) "," \
399 __stringify(default_trap_handler))
401 COND_TRAP(do_secure_storage_access);
402 COND_TRAP(do_non_secure_storage_access);
403 COND_TRAP(do_secure_storage_violation);