x86/mpx: Move bd_addr to mm_context_t

Currently bd_addr lives in mm_struct, which is otherwise architecture
independent. Architecture-specific data is supposed to live within
mm_context_t (itself contained in mm_struct).

Other x86-specific context like the pkey accounting data lives in
mm_context_t, and there's no readon the MPX data can't also live there.
So as to keep the arch-specific data togather, and to set a good example
for others, this patch moves bd_addr into x86's mm_context_t.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/1481892055-24596-1-git-send-email-mark.rutland@arm.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

arch/x86/include/asm/mmu.h

@@ -31,6 +31,10 @@ typedef struct {
 	u16 pkey_allocation_map;
 	s16 execute_only_pkey;
 #endif
+#ifdef CONFIG_X86_INTEL_MPX
+	/* address of the bounds directory */
+	void __user *bd_addr;
+#endif
 } mm_context_t;
 
 #ifdef CONFIG_SMP