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

arch/x86/include/asm/mpx.h

@@ -59,15 +59,15 @@ siginfo_t *mpx_generate_siginfo(struct pt_regs *regs);
 int mpx_handle_bd_fault(void);
 static inline int kernel_managing_mpx_tables(struct mm_struct *mm)
 {
-	return (mm->bd_addr != MPX_INVALID_BOUNDS_DIR);
+	return (mm->context.bd_addr != MPX_INVALID_BOUNDS_DIR);
 }
 static inline void mpx_mm_init(struct mm_struct *mm)
 {
 	/*
 	 * NULL is theoretically a valid place to put the bounds
 	 * directory, so point this at an invalid address.
 	 */
-	mm->bd_addr = MPX_INVALID_BOUNDS_DIR;
+	mm->context.bd_addr = MPX_INVALID_BOUNDS_DIR;
 }
 void mpx_notify_unmap(struct mm_struct *mm, struct vm_area_struct *vma,
 		      unsigned long start, unsigned long end);

arch/x86/mm/mpx.c

@@ -350,12 +350,12 @@ int mpx_enable_management(void)
 	 * The copy_xregs_to_kernel() beneath get_xsave_field_ptr() is
 	 * expected to be relatively expensive. Storing the bounds
 	 * directory here means that we do not have to do xsave in the
-	 * unmap path; we can just use mm->bd_addr instead.
+	 * unmap path; we can just use mm->context.bd_addr instead.
 	 */
 	bd_base = mpx_get_bounds_dir();
 	down_write(&mm->mmap_sem);
-	mm->bd_addr = bd_base;
-	if (mm->bd_addr == MPX_INVALID_BOUNDS_DIR)
+	mm->context.bd_addr = bd_base;
+	if (mm->context.bd_addr == MPX_INVALID_BOUNDS_DIR)
 		ret = -ENXIO;
 
 	up_write(&mm->mmap_sem);
@@ -370,7 +370,7 @@ int mpx_disable_management(void)
 		return -ENXIO;
 
 	down_write(&mm->mmap_sem);
-	mm->bd_addr = MPX_INVALID_BOUNDS_DIR;
+	mm->context.bd_addr = MPX_INVALID_BOUNDS_DIR;
 	up_write(&mm->mmap_sem);
 	return 0;
 }
@@ -947,7 +947,7 @@ static int try_unmap_single_bt(struct mm_struct *mm,
 		end = bta_end_vaddr;
 	}
 
-	bde_vaddr = mm->bd_addr + mpx_get_bd_entry_offset(mm, start);
+	bde_vaddr = mm->context.bd_addr + mpx_get_bd_entry_offset(mm, start);
 	ret = get_bt_addr(mm, bde_vaddr, &bt_addr);
 	/*
 	 * No bounds table there, so nothing to unmap.

include/linux/mm_types.h

@@ -508,10 +508,6 @@ struct mm_struct {
 	bool tlb_flush_pending;
 #endif
 	struct uprobes_state uprobes_state;
-#ifdef CONFIG_X86_INTEL_MPX
-	/* address of the bounds directory */
-	void __user *bd_addr;
-#endif
 #ifdef CONFIG_HUGETLB_PAGE
 	atomic_long_t hugetlb_usage;
 #endif