x86/uaccess: Move thread_info::addr_limit to thread_struct

struct thread_info is a legacy mess.  To prepare for its partial removal,
move thread_info::addr_limit out.

As an added benefit, this way is simpler.

Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/15bee834d09402b47ac86f2feccdf6529f9bc5b0.1468527351.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

4 files changed, 14 insertions, 19 deletions

diff --git a/arch/x86/include/asm/checksum_32.h b/arch/x86/include/asm/checksum_32.h
index 532f85e..7b53743 100644
--- a/arch/x86/include/asm/checksum_32.h
+++ b/arch/x86/include/asm/checksum_32.h
@@ -2,8 +2,7 @@
 #define _ASM_X86_CHECKSUM_32_H
 
 #include <linux/in6.h>
-
-#include <asm/uaccess.h>
+#include <linux/uaccess.h>
 
 /*
  * computes the checksum of a memory block at buff, length len,
diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index cbdfe5f..89314ed 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -371,6 +371,10 @@ extern unsigned int xstate_size;
 
 struct perf_event;
 
+typedef struct {
+	unsigned long		seg;
+} mm_segment_t;
+
 struct thread_struct {
 	/* Cached TLS descriptors: */
 	struct desc_struct	tls_array[GDT_ENTRY_TLS_ENTRIES];
@@ -419,6 +423,8 @@ struct thread_struct {
 	/* Max allowed port in the bitmap, in bytes: */
 	unsigned		io_bitmap_max;
 
+	mm_segment_t		addr_limit;
+
 	unsigned int		sig_on_uaccess_err:1;
 	unsigned int		uaccess_err:1;	/* uaccess failed */
 
@@ -493,11 +499,6 @@ static inline void load_sp0(struct tss_struct *tss,
 #define set_iopl_mask native_set_iopl_mask
 #endif /* CONFIG_PARAVIRT */
 
-typedef struct {
-	unsigned long		seg;
-} mm_segment_t;
-
-
 /* Free all resources held by a thread. */
 extern void release_thread(struct task_struct *);
 
@@ -719,6 +720,7 @@ static inline void spin_lock_prefetch(const void *x)
 	.sp0			= TOP_OF_INIT_STACK,			  \
 	.sysenter_cs		= __KERNEL_CS,				  \
 	.io_bitmap_ptr		= NULL,					  \
+	.addr_limit		= KERNEL_DS,				  \
 }
 
 extern unsigned long thread_saved_pc(struct task_struct *tsk);
@@ -768,8 +770,9 @@ extern unsigned long thread_saved_pc(struct task_struct *tsk);
 #define STACK_TOP		TASK_SIZE
 #define STACK_TOP_MAX		TASK_SIZE_MAX
 
-#define INIT_THREAD  { \
-	.sp0 = TOP_OF_INIT_STACK \
+#define INIT_THREAD  {						\
+	.sp0			= TOP_OF_INIT_STACK,		\
+	.addr_limit		= KERNEL_DS,			\
 }
 
 /*
diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thread_info.h
index 7c47bb6..89bff04 100644
--- a/arch/x86/include/asm/thread_info.h
+++ b/arch/x86/include/asm/thread_info.h
@@ -57,7 +57,6 @@ struct thread_info {
 	__u32			flags;		/* low level flags */
 	__u32			status;		/* thread synchronous flags */
 	__u32			cpu;		/* current CPU */
-	mm_segment_t		addr_limit;
 };
 
 #define INIT_THREAD_INFO(tsk)			\
@@ -65,7 +64,6 @@ struct thread_info {
 	.task		= &tsk,			\
 	.flags		= 0,			\
 	.cpu		= 0,			\
-	.addr_limit	= KERNEL_DS,		\
 }
 
 #define init_thread_info	(init_thread_union.thread_info)
@@ -184,11 +182,6 @@ static inline unsigned long current_stack_pointer(void)
 # define cpu_current_top_of_stack (cpu_tss + TSS_sp0)
 #endif
 
-/* Load thread_info address into "reg" */
-#define GET_THREAD_INFO(reg) \
-	_ASM_MOV PER_CPU_VAR(cpu_current_top_of_stack),reg ; \
-	_ASM_SUB $(THREAD_SIZE),reg ;
-
 /*
  * ASM operand which evaluates to a 'thread_info' address of
  * the current task, if it is known that "reg" is exactly "off"
diff --git a/arch/x86/include/asm/uaccess.h b/arch/x86/include/asm/uaccess.h
index 8f66e56..c03bfb6 100644
--- a/arch/x86/include/asm/uaccess.h
+++ b/arch/x86/include/asm/uaccess.h
@@ -29,12 +29,12 @@
 #define USER_DS 	MAKE_MM_SEG(TASK_SIZE_MAX)
 
 #define get_ds()	(KERNEL_DS)
-#define get_fs()	(current_thread_info()->addr_limit)
-#define set_fs(x)	(current_thread_info()->addr_limit = (x))
+#define get_fs()	(current->thread.addr_limit)
+#define set_fs(x)	(current->thread.addr_limit = (x))
 
 #define segment_eq(a, b)	((a).seg == (b).seg)
 
-#define user_addr_max() (current_thread_info()->addr_limit.seg)
+#define user_addr_max() (current->thread.addr_limit.seg)
 #define __addr_ok(addr) 	\
 	((unsigned long __force)(addr) < user_addr_max())