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-rw-r--r--arch/s390/kernel/traps.c267
1 files changed, 267 insertions, 0 deletions
diff --git a/arch/s390/kernel/traps.c b/arch/s390/kernel/traps.c
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+++ b/arch/s390/kernel/traps.c
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+// SPDX-License-Identifier: GPL-2.0
+/*
+ * S390 version
+ * Copyright IBM Corp. 1999, 2000
+ * Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com),
+ * Denis Joseph Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com),
+ *
+ * Derived from "arch/i386/kernel/traps.c"
+ * Copyright (C) 1991, 1992 Linus Torvalds
+ */
+
+/*
+ * 'Traps.c' handles hardware traps and faults after we have saved some
+ * state in 'asm.s'.
+ */
+#include <linux/kprobes.h>
+#include <linux/kdebug.h>
+#include <linux/extable.h>
+#include <linux/ptrace.h>
+#include <linux/sched.h>
+#include <linux/sched/debug.h>
+#include <linux/mm.h>
+#include <linux/slab.h>
+#include <linux/uaccess.h>
+#include <linux/cpu.h>
+#include <asm/fpu/api.h>
+#include "entry.h"
+
+static inline void __user *get_trap_ip(struct pt_regs *regs)
+{
+ unsigned long address;
+
+ if (regs->int_code & 0x200)
+ address = *(unsigned long *)(current->thread.trap_tdb + 24);
+ else
+ address = regs->psw.addr;
+ return (void __user *) (address - (regs->int_code >> 16));
+}
+
+int is_valid_bugaddr(unsigned long addr)
+{
+ return 1;
+}
+
+void do_report_trap(struct pt_regs *regs, int si_signo, int si_code, char *str)
+{
+ if (user_mode(regs)) {
+ force_sig_fault(si_signo, si_code, get_trap_ip(regs), current);
+ report_user_fault(regs, si_signo, 0);
+ } else {
+ const struct exception_table_entry *fixup;
+ fixup = search_exception_tables(regs->psw.addr);
+ if (fixup)
+ regs->psw.addr = extable_fixup(fixup);
+ else {
+ enum bug_trap_type btt;
+
+ btt = report_bug(regs->psw.addr, regs);
+ if (btt == BUG_TRAP_TYPE_WARN)
+ return;
+ die(regs, str);
+ }
+ }
+}
+
+static void do_trap(struct pt_regs *regs, int si_signo, int si_code, char *str)
+{
+ if (notify_die(DIE_TRAP, str, regs, 0,
+ regs->int_code, si_signo) == NOTIFY_STOP)
+ return;
+ do_report_trap(regs, si_signo, si_code, str);
+}
+NOKPROBE_SYMBOL(do_trap);
+
+void do_per_trap(struct pt_regs *regs)
+{
+ if (notify_die(DIE_SSTEP, "sstep", regs, 0, 0, SIGTRAP) == NOTIFY_STOP)
+ return;
+ if (!current->ptrace)
+ return;
+ force_sig_fault(SIGTRAP, TRAP_HWBKPT,
+ (void __force __user *) current->thread.per_event.address, current);
+}
+NOKPROBE_SYMBOL(do_per_trap);
+
+void default_trap_handler(struct pt_regs *regs)
+{
+ if (user_mode(regs)) {
+ report_user_fault(regs, SIGSEGV, 0);
+ do_exit(SIGSEGV);
+ } else
+ die(regs, "Unknown program exception");
+}
+
+#define DO_ERROR_INFO(name, signr, sicode, str) \
+void name(struct pt_regs *regs) \
+{ \
+ do_trap(regs, signr, sicode, str); \
+}
+
+DO_ERROR_INFO(addressing_exception, SIGILL, ILL_ILLADR,
+ "addressing exception")
+DO_ERROR_INFO(execute_exception, SIGILL, ILL_ILLOPN,
+ "execute exception")
+DO_ERROR_INFO(divide_exception, SIGFPE, FPE_INTDIV,
+ "fixpoint divide exception")
+DO_ERROR_INFO(overflow_exception, SIGFPE, FPE_INTOVF,
+ "fixpoint overflow exception")
+DO_ERROR_INFO(hfp_overflow_exception, SIGFPE, FPE_FLTOVF,
+ "HFP overflow exception")
+DO_ERROR_INFO(hfp_underflow_exception, SIGFPE, FPE_FLTUND,
+ "HFP underflow exception")
+DO_ERROR_INFO(hfp_significance_exception, SIGFPE, FPE_FLTRES,
+ "HFP significance exception")
+DO_ERROR_INFO(hfp_divide_exception, SIGFPE, FPE_FLTDIV,
+ "HFP divide exception")
+DO_ERROR_INFO(hfp_sqrt_exception, SIGFPE, FPE_FLTINV,
+ "HFP square root exception")
+DO_ERROR_INFO(operand_exception, SIGILL, ILL_ILLOPN,
+ "operand exception")
+DO_ERROR_INFO(privileged_op, SIGILL, ILL_PRVOPC,
+ "privileged operation")
+DO_ERROR_INFO(special_op_exception, SIGILL, ILL_ILLOPN,
+ "special operation exception")
+DO_ERROR_INFO(transaction_exception, SIGILL, ILL_ILLOPN,
+ "transaction constraint exception")
+
+static inline void do_fp_trap(struct pt_regs *regs, __u32 fpc)
+{
+ int si_code = 0;
+ /* FPC[2] is Data Exception Code */
+ if ((fpc & 0x00000300) == 0) {
+ /* bits 6 and 7 of DXC are 0 iff IEEE exception */
+ if (fpc & 0x8000) /* invalid fp operation */
+ si_code = FPE_FLTINV;
+ else if (fpc & 0x4000) /* div by 0 */
+ si_code = FPE_FLTDIV;
+ else if (fpc & 0x2000) /* overflow */
+ si_code = FPE_FLTOVF;
+ else if (fpc & 0x1000) /* underflow */
+ si_code = FPE_FLTUND;
+ else if (fpc & 0x0800) /* inexact */
+ si_code = FPE_FLTRES;
+ }
+ do_trap(regs, SIGFPE, si_code, "floating point exception");
+}
+
+void translation_exception(struct pt_regs *regs)
+{
+ /* May never happen. */
+ panic("Translation exception");
+}
+
+void illegal_op(struct pt_regs *regs)
+{
+ __u8 opcode[6];
+ __u16 __user *location;
+ int is_uprobe_insn = 0;
+ int signal = 0;
+
+ location = get_trap_ip(regs);
+
+ if (user_mode(regs)) {
+ if (get_user(*((__u16 *) opcode), (__u16 __user *) location))
+ return;
+ if (*((__u16 *) opcode) == S390_BREAKPOINT_U16) {
+ if (current->ptrace)
+ force_sig_fault(SIGTRAP, TRAP_BRKPT, location, current);
+ else
+ signal = SIGILL;
+#ifdef CONFIG_UPROBES
+ } else if (*((__u16 *) opcode) == UPROBE_SWBP_INSN) {
+ is_uprobe_insn = 1;
+#endif
+ } else
+ signal = SIGILL;
+ }
+ /*
+ * We got either an illegal op in kernel mode, or user space trapped
+ * on a uprobes illegal instruction. See if kprobes or uprobes picks
+ * it up. If not, SIGILL.
+ */
+ if (is_uprobe_insn || !user_mode(regs)) {
+ if (notify_die(DIE_BPT, "bpt", regs, 0,
+ 3, SIGTRAP) != NOTIFY_STOP)
+ signal = SIGILL;
+ }
+ if (signal)
+ do_trap(regs, signal, ILL_ILLOPC, "illegal operation");
+}
+NOKPROBE_SYMBOL(illegal_op);
+
+DO_ERROR_INFO(specification_exception, SIGILL, ILL_ILLOPN,
+ "specification exception");
+
+void vector_exception(struct pt_regs *regs)
+{
+ int si_code, vic;
+
+ if (!MACHINE_HAS_VX) {
+ do_trap(regs, SIGILL, ILL_ILLOPN, "illegal operation");
+ return;
+ }
+
+ /* get vector interrupt code from fpc */
+ save_fpu_regs();
+ vic = (current->thread.fpu.fpc & 0xf00) >> 8;
+ switch (vic) {
+ case 1: /* invalid vector operation */
+ si_code = FPE_FLTINV;
+ break;
+ case 2: /* division by zero */
+ si_code = FPE_FLTDIV;
+ break;
+ case 3: /* overflow */
+ si_code = FPE_FLTOVF;
+ break;
+ case 4: /* underflow */
+ si_code = FPE_FLTUND;
+ break;
+ case 5: /* inexact */
+ si_code = FPE_FLTRES;
+ break;
+ default: /* unknown cause */
+ si_code = 0;
+ }
+ do_trap(regs, SIGFPE, si_code, "vector exception");
+}
+
+void data_exception(struct pt_regs *regs)
+{
+ int signal = 0;
+
+ save_fpu_regs();
+ if (current->thread.fpu.fpc & FPC_DXC_MASK)
+ signal = SIGFPE;
+ else
+ signal = SIGILL;
+ if (signal == SIGFPE)
+ do_fp_trap(regs, current->thread.fpu.fpc);
+ else if (signal)
+ do_trap(regs, signal, ILL_ILLOPN, "data exception");
+}
+
+void space_switch_exception(struct pt_regs *regs)
+{
+ /* Set user psw back to home space mode. */
+ if (user_mode(regs))
+ regs->psw.mask |= PSW_ASC_HOME;
+ /* Send SIGILL. */
+ do_trap(regs, SIGILL, ILL_PRVOPC, "space switch event");
+}
+
+void kernel_stack_overflow(struct pt_regs *regs)
+{
+ bust_spinlocks(1);
+ printk("Kernel stack overflow.\n");
+ show_regs(regs);
+ bust_spinlocks(0);
+ panic("Corrupt kernel stack, can't continue.");
+}
+NOKPROBE_SYMBOL(kernel_stack_overflow);
+
+void __init trap_init(void)
+{
+ local_mcck_enable();
+}
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