x86/tss: Move I/O bitmap data into a seperate struct

Move the non hardware portion of I/O bitmap data into a seperate struct for
readability sake.
Originally-by: NIngo Molnar <mingo@kernel.org>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

arch/x86/include/asm/processor.h

@@ -328,11 +328,11 @@ struct x86_hw_tss {
  * IO-bitmap sizes:
  */
 #define IO_BITMAP_BITS			65536
-#define IO_BITMAP_BYTES			(IO_BITMAP_BITS/8)
-#define IO_BITMAP_LONGS			(IO_BITMAP_BYTES/sizeof(long))
+#define IO_BITMAP_BYTES			(IO_BITMAP_BITS / BITS_PER_BYTE)
+#define IO_BITMAP_LONGS			(IO_BITMAP_BYTES / sizeof(long))
 
-#define IO_BITMAP_OFFSET_VALID				\
-	(offsetof(struct tss_struct, io_bitmap) -	\
+#define IO_BITMAP_OFFSET_VALID					\
+	(offsetof(struct tss_struct, io_bitmap.bitmap) -	\
 	 offsetof(struct tss_struct, x86_tss))
 
 /*
@@ -356,14 +356,10 @@ struct entry_stack_page {
 	struct entry_stack stack;
 } __aligned(PAGE_SIZE);
 
-struct tss_struct {
-	/*
-	 * The fixed hardware portion.  This must not cross a page boundary
-	 * at risk of violating the SDM's advice and potentially triggering
-	 * errata.
-	 */
-	struct x86_hw_tss	x86_tss;
-
+/*
+ * All IO bitmap related data stored in the TSS:
+ */
+struct x86_io_bitmap {
 	/*
 	 * Store the dirty size of the last io bitmap offender. The next
 	 * one will have to do the cleanup as the switch out to a non io
@@ -371,7 +367,7 @@ struct tss_struct {
 	 * outside of the TSS limit. So for sane tasks there is no need to
 	 * actually touch the io_bitmap at all.
 	 */
-	unsigned int		io_bitmap_prev_max;
+	unsigned int		prev_max;
 
 	/*
 	 * The extra 1 is there because the CPU will access an
@@ -379,7 +375,18 @@ struct tss_struct {
 	 * bitmap. The extra byte must be all 1 bits, and must
 	 * be within the limit.
 	 */
-	unsigned long		io_bitmap[IO_BITMAP_LONGS + 1];
+	unsigned long		bitmap[IO_BITMAP_LONGS + 1];
+};
+
+struct tss_struct {
+	/*
+	 * The fixed hardware portion.  This must not cross a page boundary
+	 * at risk of violating the SDM's advice and potentially triggering
+	 * errata.
+	 */
+	struct x86_hw_tss	x86_tss;
+
+	struct x86_io_bitmap	io_bitmap;
 } __aligned(PAGE_SIZE);
 
 DECLARE_PER_CPU_PAGE_ALIGNED(struct tss_struct, cpu_tss_rw);

arch/x86/kernel/cpu/common.c

@@ -1861,8 +1861,8 @@ void cpu_init(void)
 	/* Initialize the TSS. */
 	tss_setup_ist(tss);
 	tss->x86_tss.io_bitmap_base = IO_BITMAP_OFFSET_INVALID;
-	tss->io_bitmap_prev_max = 0;
-	memset(tss->io_bitmap, 0xff, sizeof(tss->io_bitmap));
+	tss->io_bitmap.prev_max = 0;
+	memset(tss->io_bitmap.bitmap, 0xff, sizeof(tss->io_bitmap.bitmap));
 	set_tss_desc(cpu, &get_cpu_entry_area(cpu)->tss.x86_tss);
 
 	load_TR_desc();

arch/x86/kernel/ioport.c

@@ -81,9 +81,9 @@ long ksys_ioperm(unsigned long from, unsigned long num, int turn_on)
 
 	/* Update the TSS */
 	tss = this_cpu_ptr(&cpu_tss_rw);
-	memcpy(tss->io_bitmap, t->io_bitmap_ptr, bytes_updated);
+	memcpy(tss->io_bitmap.bitmap, t->io_bitmap_ptr, bytes_updated);
 	/* Store the new end of the zero bits */
-	tss->io_bitmap_prev_max = bytes;
+	tss->io_bitmap.prev_max = bytes;
 	/* Make the bitmap base in the TSS valid */
 	tss->x86_tss.io_bitmap_base = IO_BITMAP_OFFSET_VALID;
 	/* Make sure the TSS limit covers the I/O bitmap. */

arch/x86/kernel/process.c

@@ -374,11 +374,11 @@ static inline void switch_to_bitmap(struct thread_struct *next,
 		 * bits permitted, then the copy needs to cover those as
 		 * well so they get turned off.
 		 */
-		memcpy(tss->io_bitmap, next->io_bitmap_ptr,
-		       max(tss->io_bitmap_prev_max, next->io_bitmap_max));
+		memcpy(tss->io_bitmap.bitmap, next->io_bitmap_ptr,
+		       max(tss->io_bitmap.prev_max, next->io_bitmap_max));
 
 		/* Store the new max and set io_bitmap_base valid */
-		tss->io_bitmap_prev_max = next->io_bitmap_max;
+		tss->io_bitmap.prev_max = next->io_bitmap_max;
 		tss->x86_tss.io_bitmap_base = IO_BITMAP_OFFSET_VALID;
 
 		/*