[PATCH] UML: add generic BUG support

The BUG changes in -mm3 need some arch support.  This patch adds the UML
support needed.  For the most part, it was stolen from the underlying
architecture.  The exception is the kernel eip < PAGE_OFFSET test, which is
wrong for skas mode UMLs.

Signed-off-by: Jeff Dike <jdike@addtoit.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

arch/um/Kconfig

@@ -47,6 +47,11 @@ config GENERIC_CALIBRATE_DELAY
 	bool
 	default y
 
+config GENERIC_BUG
+	bool
+	default y
+	depends on BUG
+
 # Used in kernel/irq/manage.c and include/linux/irq.h
 config IRQ_RELEASE_METHOD
 	bool

arch/um/sys-i386/Makefile

@@ -1,4 +1,4 @@
-obj-y = bugs.o checksum.o delay.o fault.o ksyms.o ldt.o ptrace.o \
+obj-y = bug.o bugs.o checksum.o delay.o fault.o ksyms.o ldt.o ptrace.o \
 	ptrace_user.o setjmp.o signal.o sigcontext.o syscalls.o sysrq.o \
 	sys_call_table.o tls.o
 

arch/um/sys-i386/bug.c

@@ -0,0 +1,20 @@
+/*
+ * Copyright (C) 2006 Jeff Dike (jdike@addtoit.com)
+ * Licensed under the GPL V2
+ */
+
+#include <linux/uaccess.h>
+
+/* Mostly copied from i386/x86_86 - eliminated the eip < PAGE_OFFSET because
+ * that's not relevent in skas mode.
+ */
+
+int is_valid_bugaddr(unsigned long eip)
+{
+	unsigned short ud2;
+
+	if (probe_kernel_address((unsigned short __user *)eip, ud2))
+		return 0;
+
+	return ud2 == 0x0b0f;
+}

arch/um/sys-x86_64/Makefile

@@ -4,7 +4,7 @@
 # Licensed under the GPL
 #
 
-obj-y = bugs.o delay.o fault.o ldt.o mem.o ptrace.o ptrace_user.o \
+obj-y = bug.o bugs.o delay.o fault.o ldt.o mem.o ptrace.o ptrace_user.o \
 	setjmp.o sigcontext.o signal.o syscalls.o syscall_table.o sysrq.o \
 	ksyms.o tls.o
 

arch/um/sys-x86_64/bug.c

@@ -0,0 +1,20 @@
+/*
+ * Copyright (C) 2006 Jeff Dike (jdike@addtoit.com)
+ * Licensed under the GPL V2
+ */
+
+#include <linux/uaccess.h>
+
+/* Mostly copied from i386/x86_86 - eliminated the eip < PAGE_OFFSET because
+ * that's not relevent in skas mode.
+ */
+
+int is_valid_bugaddr(unsigned long eip)
+{
+	unsigned short ud2;
+
+	if (probe_kernel_address((unsigned short __user *)eip, ud2))
+		return 0;
+
+	return ud2 == 0x0b0f;
+}

include/asm-um/bug.h

@@ -1,4 +1,6 @@
 #ifndef __UM_BUG_H
 #define __UM_BUG_H
-#include <asm-generic/bug.h>
+
+#include <asm/arch/bug.h>
+
 #endif