Merge branch 'for-linus-4.3-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/rw/uml

Pull UML fixes from Richard Weinberger:
 "This contains four overdue UML regression fixes"

* 'for-linus-4.3-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/rw/uml:
  um: Fix kernel mode fault condition
  um: Fix waitpid() usage in helper code
  um: Do not rely on libc to provide modify_ldt()
  um: Fix out-of-tree build

arch/um/Makefile

@@ -70,8 +70,8 @@ KBUILD_AFLAGS += $(ARCH_INCLUDE)
 
 USER_CFLAGS = $(patsubst $(KERNEL_DEFINES),,$(patsubst -I%,,$(KBUILD_CFLAGS))) \
 		$(ARCH_INCLUDE) $(MODE_INCLUDE) $(filter -I%,$(CFLAGS)) \
-		-D_FILE_OFFSET_BITS=64 -idirafter include \
-		-D__KERNEL__ -D__UM_HOST__
+		-D_FILE_OFFSET_BITS=64 -idirafter $(srctree)/include \
+		-idirafter $(obj)/include -D__KERNEL__ -D__UM_HOST__
 
 #This will adjust *FLAGS accordingly to the platform.
 include $(ARCH_DIR)/Makefile-os-$(OS)

arch/um/kernel/trap.c

@@ -220,7 +220,7 @@ unsigned long segv(struct faultinfo fi, unsigned long ip, int is_user,
 		show_regs(container_of(regs, struct pt_regs, regs));
 		panic("Segfault with no mm");
 	}
-	else if (!is_user && address < TASK_SIZE) {
+	else if (!is_user && address > PAGE_SIZE && address < TASK_SIZE) {
 		show_regs(container_of(regs, struct pt_regs, regs));
 		panic("Kernel tried to access user memory at addr 0x%lx, ip 0x%lx",
 		       address, ip);

arch/um/os-Linux/helper.c

@@ -96,7 +96,7 @@ int run_helper(void (*pre_exec)(void *), void *pre_data, char **argv)
 			       "ret = %d\n", -n);
 			ret = n;
 		}
-		CATCH_EINTR(waitpid(pid, NULL, __WCLONE));
+		CATCH_EINTR(waitpid(pid, NULL, __WALL));
 	}
 
 out_free2:
@@ -129,7 +129,7 @@ int run_helper_thread(int (*proc)(void *), void *arg, unsigned int flags,
 		return err;
 	}
 	if (stack_out == NULL) {
-		CATCH_EINTR(pid = waitpid(pid, &status, __WCLONE));
+		CATCH_EINTR(pid = waitpid(pid, &status, __WALL));
 		if (pid < 0) {
 			err = -errno;
 			printk(UM_KERN_ERR "run_helper_thread - wait failed, "
@@ -148,7 +148,7 @@ int run_helper_thread(int (*proc)(void *), void *arg, unsigned int flags,
 int helper_wait(int pid)
 {
 	int ret, status;
-	int wflags = __WCLONE;
+	int wflags = __WALL;
 
 	CATCH_EINTR(ret = waitpid(pid, &status, wflags));
 	if (ret < 0) {

arch/x86/um/ldt.c

@@ -12,7 +12,10 @@
 #include <skas.h>
 #include <sysdep/tls.h>
 
-extern int modify_ldt(int func, void *ptr, unsigned long bytecount);
+static inline int modify_ldt (int func, void *ptr, unsigned long bytecount)
+{
+	return syscall(__NR_modify_ldt, func, ptr, bytecount);
+}
 
 static long write_ldt_entry(struct mm_id *mm_idp, int func,
 		     struct user_desc *desc, void **addr, int done)