268 lines
6.9 KiB
C
268 lines
6.9 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* S390 version
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* Copyright IBM Corp. 1999, 2000
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* Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com),
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* Denis Joseph Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com),
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*
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* Derived from "arch/i386/kernel/traps.c"
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* Copyright (C) 1991, 1992 Linus Torvalds
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*/
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/*
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* 'Traps.c' handles hardware traps and faults after we have saved some
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* state in 'asm.s'.
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*/
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#include <linux/kprobes.h>
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#include <linux/kdebug.h>
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#include <linux/extable.h>
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#include <linux/ptrace.h>
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#include <linux/sched.h>
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#include <linux/sched/debug.h>
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#include <linux/mm.h>
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#include <linux/slab.h>
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#include <linux/uaccess.h>
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#include <linux/cpu.h>
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#include <asm/fpu/api.h>
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#include "entry.h"
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static inline void __user *get_trap_ip(struct pt_regs *regs)
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{
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unsigned long address;
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if (regs->int_code & 0x200)
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address = *(unsigned long *)(current->thread.trap_tdb + 24);
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else
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address = regs->psw.addr;
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return (void __user *) (address - (regs->int_code >> 16));
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}
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int is_valid_bugaddr(unsigned long addr)
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{
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return 1;
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}
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void do_report_trap(struct pt_regs *regs, int si_signo, int si_code, char *str)
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{
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if (user_mode(regs)) {
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force_sig_fault(si_signo, si_code, get_trap_ip(regs), current);
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report_user_fault(regs, si_signo, 0);
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} else {
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const struct exception_table_entry *fixup;
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fixup = search_exception_tables(regs->psw.addr);
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if (fixup)
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regs->psw.addr = extable_fixup(fixup);
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else {
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enum bug_trap_type btt;
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btt = report_bug(regs->psw.addr, regs);
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if (btt == BUG_TRAP_TYPE_WARN)
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return;
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die(regs, str);
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}
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}
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}
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static void do_trap(struct pt_regs *regs, int si_signo, int si_code, char *str)
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{
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if (notify_die(DIE_TRAP, str, regs, 0,
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regs->int_code, si_signo) == NOTIFY_STOP)
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return;
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do_report_trap(regs, si_signo, si_code, str);
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}
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NOKPROBE_SYMBOL(do_trap);
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void do_per_trap(struct pt_regs *regs)
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{
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if (notify_die(DIE_SSTEP, "sstep", regs, 0, 0, SIGTRAP) == NOTIFY_STOP)
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return;
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if (!current->ptrace)
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return;
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force_sig_fault(SIGTRAP, TRAP_HWBKPT,
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(void __force __user *) current->thread.per_event.address, current);
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}
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NOKPROBE_SYMBOL(do_per_trap);
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void default_trap_handler(struct pt_regs *regs)
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{
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if (user_mode(regs)) {
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report_user_fault(regs, SIGSEGV, 0);
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do_exit(SIGSEGV);
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} else
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die(regs, "Unknown program exception");
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}
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#define DO_ERROR_INFO(name, signr, sicode, str) \
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void name(struct pt_regs *regs) \
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{ \
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do_trap(regs, signr, sicode, str); \
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}
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DO_ERROR_INFO(addressing_exception, SIGILL, ILL_ILLADR,
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"addressing exception")
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DO_ERROR_INFO(execute_exception, SIGILL, ILL_ILLOPN,
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"execute exception")
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DO_ERROR_INFO(divide_exception, SIGFPE, FPE_INTDIV,
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"fixpoint divide exception")
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DO_ERROR_INFO(overflow_exception, SIGFPE, FPE_INTOVF,
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"fixpoint overflow exception")
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DO_ERROR_INFO(hfp_overflow_exception, SIGFPE, FPE_FLTOVF,
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"HFP overflow exception")
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DO_ERROR_INFO(hfp_underflow_exception, SIGFPE, FPE_FLTUND,
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"HFP underflow exception")
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DO_ERROR_INFO(hfp_significance_exception, SIGFPE, FPE_FLTRES,
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"HFP significance exception")
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DO_ERROR_INFO(hfp_divide_exception, SIGFPE, FPE_FLTDIV,
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"HFP divide exception")
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DO_ERROR_INFO(hfp_sqrt_exception, SIGFPE, FPE_FLTINV,
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"HFP square root exception")
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DO_ERROR_INFO(operand_exception, SIGILL, ILL_ILLOPN,
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"operand exception")
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DO_ERROR_INFO(privileged_op, SIGILL, ILL_PRVOPC,
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"privileged operation")
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DO_ERROR_INFO(special_op_exception, SIGILL, ILL_ILLOPN,
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"special operation exception")
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DO_ERROR_INFO(transaction_exception, SIGILL, ILL_ILLOPN,
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"transaction constraint exception")
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static inline void do_fp_trap(struct pt_regs *regs, __u32 fpc)
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{
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int si_code = 0;
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/* FPC[2] is Data Exception Code */
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if ((fpc & 0x00000300) == 0) {
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/* bits 6 and 7 of DXC are 0 iff IEEE exception */
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if (fpc & 0x8000) /* invalid fp operation */
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si_code = FPE_FLTINV;
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else if (fpc & 0x4000) /* div by 0 */
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si_code = FPE_FLTDIV;
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else if (fpc & 0x2000) /* overflow */
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si_code = FPE_FLTOVF;
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else if (fpc & 0x1000) /* underflow */
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si_code = FPE_FLTUND;
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else if (fpc & 0x0800) /* inexact */
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si_code = FPE_FLTRES;
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}
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do_trap(regs, SIGFPE, si_code, "floating point exception");
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}
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void translation_exception(struct pt_regs *regs)
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{
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/* May never happen. */
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panic("Translation exception");
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}
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void illegal_op(struct pt_regs *regs)
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{
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__u8 opcode[6];
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__u16 __user *location;
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int is_uprobe_insn = 0;
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int signal = 0;
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location = get_trap_ip(regs);
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if (user_mode(regs)) {
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if (get_user(*((__u16 *) opcode), (__u16 __user *) location))
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return;
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if (*((__u16 *) opcode) == S390_BREAKPOINT_U16) {
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if (current->ptrace)
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force_sig_fault(SIGTRAP, TRAP_BRKPT, location, current);
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else
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signal = SIGILL;
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#ifdef CONFIG_UPROBES
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} else if (*((__u16 *) opcode) == UPROBE_SWBP_INSN) {
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is_uprobe_insn = 1;
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#endif
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} else
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signal = SIGILL;
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}
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/*
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* We got either an illegal op in kernel mode, or user space trapped
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* on a uprobes illegal instruction. See if kprobes or uprobes picks
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* it up. If not, SIGILL.
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*/
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if (is_uprobe_insn || !user_mode(regs)) {
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if (notify_die(DIE_BPT, "bpt", regs, 0,
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3, SIGTRAP) != NOTIFY_STOP)
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signal = SIGILL;
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}
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if (signal)
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do_trap(regs, signal, ILL_ILLOPC, "illegal operation");
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}
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NOKPROBE_SYMBOL(illegal_op);
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DO_ERROR_INFO(specification_exception, SIGILL, ILL_ILLOPN,
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"specification exception");
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void vector_exception(struct pt_regs *regs)
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{
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int si_code, vic;
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if (!MACHINE_HAS_VX) {
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do_trap(regs, SIGILL, ILL_ILLOPN, "illegal operation");
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return;
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}
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/* get vector interrupt code from fpc */
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save_fpu_regs();
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vic = (current->thread.fpu.fpc & 0xf00) >> 8;
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switch (vic) {
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case 1: /* invalid vector operation */
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si_code = FPE_FLTINV;
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break;
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case 2: /* division by zero */
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si_code = FPE_FLTDIV;
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break;
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case 3: /* overflow */
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si_code = FPE_FLTOVF;
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break;
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case 4: /* underflow */
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si_code = FPE_FLTUND;
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break;
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case 5: /* inexact */
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si_code = FPE_FLTRES;
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break;
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default: /* unknown cause */
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si_code = 0;
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}
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do_trap(regs, SIGFPE, si_code, "vector exception");
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}
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void data_exception(struct pt_regs *regs)
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{
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int signal = 0;
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save_fpu_regs();
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if (current->thread.fpu.fpc & FPC_DXC_MASK)
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signal = SIGFPE;
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else
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signal = SIGILL;
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if (signal == SIGFPE)
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do_fp_trap(regs, current->thread.fpu.fpc);
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else if (signal)
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do_trap(regs, signal, ILL_ILLOPN, "data exception");
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}
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void space_switch_exception(struct pt_regs *regs)
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{
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/* Set user psw back to home space mode. */
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if (user_mode(regs))
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regs->psw.mask |= PSW_ASC_HOME;
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/* Send SIGILL. */
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do_trap(regs, SIGILL, ILL_PRVOPC, "space switch event");
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}
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void kernel_stack_overflow(struct pt_regs *regs)
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{
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bust_spinlocks(1);
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printk("Kernel stack overflow.\n");
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show_regs(regs);
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bust_spinlocks(0);
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panic("Corrupt kernel stack, can't continue.");
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}
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NOKPROBE_SYMBOL(kernel_stack_overflow);
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void __init trap_init(void)
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{
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local_mcck_enable();
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}
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