Initial import

1 files changed, 342 insertions, 0 deletions

diff --git a/arch/s390/kernel/traps.c b/arch/s390/kernel/traps.c
new file mode 100644
index 000000000..4d96c9f53
--- /dev/null
+++ b/arch/s390/kernel/traps.c
@@ -0,0 +1,342 @@
+/*
+ *  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/module.h>
+#include <linux/ptrace.h>
+#include <linux/sched.h>
+#include <linux/mm.h>
+#include <linux/slab.h>
+#include <asm/switch_to.h>
+#include "entry.h"
+
+int show_unhandled_signals = 1;
+
+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)) & PSW_ADDR_INSN);
+}
+
+static inline void report_user_fault(struct pt_regs *regs, int signr)
+{
+	if ((task_pid_nr(current) > 1) && !show_unhandled_signals)
+		return;
+	if (!unhandled_signal(current, signr))
+		return;
+	if (!printk_ratelimit())
+		return;
+	printk("User process fault: interruption code %04x ilc:%d ",
+	       regs->int_code & 0xffff, regs->int_code >> 17);
+	print_vma_addr("in ", regs->psw.addr & PSW_ADDR_INSN);
+	printk("\n");
+	show_regs(regs);
+}
+
+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)
+{
+	siginfo_t info;
+
+	if (user_mode(regs)) {
+		info.si_signo = si_signo;
+		info.si_errno = 0;
+		info.si_code = si_code;
+		info.si_addr = get_trap_ip(regs);
+		force_sig_info(si_signo, &info, current);
+		report_user_fault(regs, si_signo);
+        } else {
+                const struct exception_table_entry *fixup;
+                fixup = search_exception_tables(regs->psw.addr & PSW_ADDR_INSN);
+                if (fixup)
+			regs->psw.addr = extable_fixup(fixup) | PSW_ADDR_AMODE;
+		else {
+			enum bug_trap_type btt;
+
+			btt = report_bug(regs->psw.addr & PSW_ADDR_INSN, 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)
+{
+	siginfo_t info;
+
+	if (notify_die(DIE_SSTEP, "sstep", regs, 0, 0, SIGTRAP) == NOTIFY_STOP)
+		return;
+	if (!current->ptrace)
+		return;
+	info.si_signo = SIGTRAP;
+	info.si_errno = 0;
+	info.si_code = TRAP_HWBKPT;
+	info.si_addr =
+		(void __force __user *) current->thread.per_event.address;
+	force_sig_info(SIGTRAP, &info, current);
+}
+NOKPROBE_SYMBOL(do_per_trap);
+
+void default_trap_handler(struct pt_regs *regs)
+{
+	if (user_mode(regs)) {
+		report_user_fault(regs, SIGSEGV);
+		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, int 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)
+{
+	siginfo_t info;
+        __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) {
+				info.si_signo = SIGTRAP;
+				info.si_errno = 0;
+				info.si_code = TRAP_BRKPT;
+				info.si_addr = location;
+				force_sig_info(SIGTRAP, &info, 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");
+
+int alloc_vector_registers(struct task_struct *tsk)
+{
+	__vector128 *vxrs;
+	int i;
+
+	/* Allocate vector register save area. */
+	vxrs = kzalloc(sizeof(__vector128) * __NUM_VXRS,
+		       GFP_KERNEL|__GFP_REPEAT);
+	if (!vxrs)
+		return -ENOMEM;
+	preempt_disable();
+	if (tsk == current)
+		save_fp_regs(tsk->thread.fp_regs.fprs);
+	/* Copy the 16 floating point registers */
+	for (i = 0; i < 16; i++)
+		*(freg_t *) &vxrs[i] = tsk->thread.fp_regs.fprs[i];
+	tsk->thread.vxrs = vxrs;
+	if (tsk == current) {
+		__ctl_set_bit(0, 17);
+		restore_vx_regs(vxrs);
+	}
+	preempt_enable();
+	return 0;
+}
+
+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 */
+	asm volatile("stfpc %0" : "=m" (current->thread.fp_regs.fpc));
+	vic = (current->thread.fp_regs.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");
+}
+
+static int __init disable_vector_extension(char *str)
+{
+	S390_lowcore.machine_flags &= ~MACHINE_FLAG_VX;
+	return 1;
+}
+__setup("novx", disable_vector_extension);
+
+void data_exception(struct pt_regs *regs)
+{
+	__u16 __user *location;
+	int signal = 0;
+
+	location = get_trap_ip(regs);
+
+	asm volatile("stfpc %0" : "=m" (current->thread.fp_regs.fpc));
+	/* Check for vector register enablement */
+	if (MACHINE_HAS_VX && !current->thread.vxrs &&
+	    (current->thread.fp_regs.fpc & FPC_DXC_MASK) == 0xfe00) {
+		alloc_vector_registers(current);
+		/* Vector data exception is suppressing, rewind psw. */
+		regs->psw.addr = __rewind_psw(regs->psw, regs->int_code >> 16);
+		clear_pt_regs_flag(regs, PIF_PER_TRAP);
+		return;
+	}
+	if (current->thread.fp_regs.fpc & FPC_DXC_MASK)
+		signal = SIGFPE;
+	else
+		signal = SIGILL;
+	if (signal == SIGFPE)
+		do_fp_trap(regs, current->thread.fp_regs.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();
+}