x86: Factor out TIF_IA32 from 32-bit address space

Factor out IA32 (compatibility instruction set) from 32-bit address
space in the thread_info flags; this is a precondition patch for x32
support.

Originally-by: H. J. Lu <hjl.tools@gmail.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Link: http://lkml.kernel.org/n/tip-4pr1xnnksprt7t0h3w5fw4rv@git.kernel.org
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index 9b9fe4a..0e900d0 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -508,6 +508,7 @@
 
 	/* Make sure to be in 64bit mode */
 	clear_thread_flag(TIF_IA32);
+	clear_thread_flag(TIF_ADDR32);
 
 	/* Ensure the corresponding mm is not marked. */
 	if (current->mm)
@@ -526,6 +527,7 @@
 
 	/* Make sure to be in 32bit mode */
 	set_thread_flag(TIF_IA32);
+	set_thread_flag(TIF_ADDR32);
 	current->personality |= force_personality32;
 
 	/* Mark the associated mm as containing 32-bit tasks. */
diff --git a/arch/x86/kernel/sys_x86_64.c b/arch/x86/kernel/sys_x86_64.c
index 0514890..f921df8 100644
--- a/arch/x86/kernel/sys_x86_64.c
+++ b/arch/x86/kernel/sys_x86_64.c
@@ -98,7 +98,7 @@
 static void find_start_end(unsigned long flags, unsigned long *begin,
 			   unsigned long *end)
 {
-	if (!test_thread_flag(TIF_IA32) && (flags & MAP_32BIT)) {
+	if (!test_thread_flag(TIF_ADDR32) && (flags & MAP_32BIT)) {
 		unsigned long new_begin;
 		/* This is usually used needed to map code in small
 		   model, so it needs to be in the first 31bit. Limit
@@ -144,7 +144,7 @@
 		    (!vma || addr + len <= vma->vm_start))
 			return addr;
 	}
-	if (((flags & MAP_32BIT) || test_thread_flag(TIF_IA32))
+	if (((flags & MAP_32BIT) || test_thread_flag(TIF_ADDR32))
 	    && len <= mm->cached_hole_size) {
 		mm->cached_hole_size = 0;
 		mm->free_area_cache = begin;
@@ -205,7 +205,7 @@
 		return addr;
 
 	/* for MAP_32BIT mappings we force the legact mmap base */
-	if (!test_thread_flag(TIF_IA32) && (flags & MAP_32BIT))
+	if (!test_thread_flag(TIF_ADDR32) && (flags & MAP_32BIT))
 		goto bottomup;
 
 	/* requesting a specific address */