um: Rework uaccess code

Rework UML's uaccess code to reuse as much as possible
from asm-generic/uaccess.c.

Signed-off-by: Richard Weinberger <richard@nod.at>

arch/x86/um/asm/checksum.h

@@ -3,6 +3,7 @@
 
 #include <linux/string.h>
 #include <linux/in6.h>
+#include <linux/uaccess.h>
 
 /*
  * computes the checksum of a memory block at buff, length len,

arch/x86/um/asm/elf.h

@@ -200,8 +200,6 @@ typedef elf_greg_t elf_gregset_t[ELF_NGREG];
 
 typedef struct user_i387_struct elf_fpregset_t;
 
-#define task_pt_regs(t) (&(t)->thread.regs)
-
 struct task_struct;
 
 extern int elf_core_copy_fpregs(struct task_struct *t, elf_fpregset_t *fpu);

arch/x86/um/asm/processor.h

@@ -28,6 +28,8 @@ static inline void rep_nop(void)
 #define cpu_relax()		rep_nop()
 #define cpu_relax_lowlatency()	cpu_relax()
 
+#define task_pt_regs(t) (&(t)->thread.regs)
+
 #include <asm/processor-generic.h>
 
 #endif

arch/x86/um/asm/segment.h

@@ -7,4 +7,12 @@ extern int host_gdt_entry_tls_min;
 #define GDT_ENTRY_TLS_MIN host_gdt_entry_tls_min
 #define GDT_ENTRY_TLS_MAX (GDT_ENTRY_TLS_MIN + GDT_ENTRY_TLS_ENTRIES - 1)
 
+typedef struct {
+	unsigned long seg;
+} mm_segment_t;
+
+#define MAKE_MM_SEG(s)	((mm_segment_t) { (s) })
+#define KERNEL_DS	MAKE_MM_SEG(~0UL)
+#define USER_DS		MAKE_MM_SEG(TASK_SIZE)
+
 #endif