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/extable.h>
21 #include <linux/ptrace.h>
22 #include <linux/sched.h>
23 #include <linux/sched/debug.h>
25 #include <linux/slab.h>
26 #include <linux/uaccess.h>
27 #include <linux/cpu.h>
28 #include <linux/entry-common.h>
29 #include <asm/fpu/api.h>
30 #include <asm/vtime.h>
33 static inline void __user *get_trap_ip(struct pt_regs *regs)
35 unsigned long address;
37 if (regs->int_code & 0x200)
38 address = *(unsigned long *)(current->thread.trap_tdb + 24);
40 address = regs->psw.addr;
41 return (void __user *) (address - (regs->int_code >> 16));
44 int is_valid_bugaddr(unsigned long addr)
49 void do_report_trap(struct pt_regs *regs, int si_signo, int si_code, char *str)
51 if (user_mode(regs)) {
52 force_sig_fault(si_signo, si_code, get_trap_ip(regs));
53 report_user_fault(regs, si_signo, 0);
55 const struct exception_table_entry *fixup;
56 fixup = s390_search_extables(regs->psw.addr);
57 if (!fixup || !ex_handle(fixup, 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 void default_trap_handler(struct pt_regs *regs)
84 if (user_mode(regs)) {
85 report_user_fault(regs, SIGSEGV, 0);
88 die(regs, "Unknown program exception");
91 #define DO_ERROR_INFO(name, signr, sicode, str) \
92 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 void translation_exception(struct pt_regs *regs)
146 /* May never happen. */
147 panic("Translation exception");
150 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 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 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 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 void monitor_event_exception(struct pt_regs *regs)
246 const struct exception_table_entry *fixup;
251 switch (report_bug(regs->psw.addr - (regs->int_code >> 16), regs)) {
252 case BUG_TRAP_TYPE_NONE:
253 fixup = s390_search_extables(regs->psw.addr);
255 ex_handle(fixup, regs);
257 case BUG_TRAP_TYPE_WARN:
259 case BUG_TRAP_TYPE_BUG:
260 die(regs, "monitor event");
265 void kernel_stack_overflow(struct pt_regs *regs)
268 printk("Kernel stack overflow.\n");
271 panic("Corrupt kernel stack, can't continue.");
273 NOKPROBE_SYMBOL(kernel_stack_overflow);
275 static void __init test_monitor_call(void)
286 panic("Monitor call doesn't work!\n");
289 void __init trap_init(void)
291 sort_extable(__start_dma_ex_table, __stop_dma_ex_table);
296 void noinstr __do_pgm_check(struct pt_regs *regs)
298 unsigned long last_break = S390_lowcore.breaking_event_addr;
299 unsigned int trapnr, syscall_redirect = 0;
300 irqentry_state_t state;
302 regs->int_code = *(u32 *)&S390_lowcore.pgm_ilc;
303 regs->int_parm_long = S390_lowcore.trans_exc_code;
305 state = irqentry_enter(regs);
307 if (user_mode(regs)) {
309 if (last_break < 4096)
311 current->thread.last_break = last_break;
312 regs->args[0] = last_break;
315 if (S390_lowcore.pgm_code & 0x0200) {
316 /* transaction abort */
317 memcpy(¤t->thread.trap_tdb, &S390_lowcore.pgm_tdb, 256);
320 if (S390_lowcore.pgm_code & PGM_INT_CODE_PER) {
321 if (user_mode(regs)) {
322 struct per_event *ev = ¤t->thread.per_event;
324 set_thread_flag(TIF_PER_TRAP);
325 ev->address = S390_lowcore.per_address;
326 ev->cause = *(u16 *)&S390_lowcore.per_code;
327 ev->paid = S390_lowcore.per_access_id;
329 /* PER event in kernel is kprobes */
330 __arch_local_irq_ssm(regs->psw.mask & ~PSW_MASK_PER);
336 if (!irqs_disabled_flags(regs->psw.mask))
338 __arch_local_irq_ssm(regs->psw.mask & ~PSW_MASK_PER);
340 trapnr = regs->int_code & PGM_INT_CODE_MASK;
342 pgm_check_table[trapnr](regs);
343 syscall_redirect = user_mode(regs) && test_pt_regs_flag(regs, PIF_SYSCALL);
346 irqentry_exit(regs, state);
348 if (syscall_redirect) {
349 enter_from_user_mode(regs);
351 regs->orig_gpr2 = regs->gprs[2];