uaccess: remove CONFIG_SET_FS

There are no remaining callers of set_fs(), so CONFIG_SET_FS
can be removed globally, along with the thread_info field and
any references to it.

This turns access_ok() into a cheaper check against TASK_SIZE_MAX.

As CONFIG_SET_FS is now gone, drop all remaining references to
set_fs()/get_fs(), mm_segment_t, user_addr_max() and uaccess_kernel().

Acked-by: Sam Ravnborg <sam@ravnborg.org> # for sparc32 changes
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Tested-by: Sergey Matyukevich <sergey.matyukevich@synopsys.com> # for arc changes
Acked-by: Stafford Horne <shorne@gmail.com> # [openrisc, asm-generic]
Acked-by: Dinh Nguyen <dinguyen@kernel.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

6 files changed, 0 insertions, 101 deletions

diff --git a/arch/xtensa/Kconfig b/arch/xtensa/Kconfig
index 8ac599aa6d99..09f7616a0b46 100644
--- a/arch/xtensa/Kconfig
+++ b/arch/xtensa/Kconfig
@@ -40,7 +40,6 @@ config XTENSA
 	select IRQ_DOMAIN
 	select MODULES_USE_ELF_RELA
 	select PERF_USE_VMALLOC
-	select SET_FS
 	select TRACE_IRQFLAGS_SUPPORT
 	select VIRT_TO_BUS
 	help
diff --git a/arch/xtensa/include/asm/asm-uaccess.h b/arch/xtensa/include/asm/asm-uaccess.h
index 7f6cf4151843..7cec869136e3 100644
--- a/arch/xtensa/include/asm/asm-uaccess.h
+++ b/arch/xtensa/include/asm/asm-uaccess.h
@@ -24,76 +24,6 @@
 #include <asm/processor.h>
 
 /*
- * These assembly macros mirror the C macros in asm/uaccess.h.  They
- * should always have identical functionality.  See
- * arch/xtensa/kernel/sys.S for usage.
- */
-
-#define KERNEL_DS	0
-#define USER_DS		1
-
-/*
- * get_fs reads current->thread.current_ds into a register.
- * On Entry:
- * 	<ad>	anything
- * 	<sp>	stack
- * On Exit:
- * 	<ad>	contains current->thread.current_ds
- */
-	.macro	get_fs	ad, sp
-	GET_CURRENT(\ad,\sp)
-#if THREAD_CURRENT_DS > 1020
-	addi	\ad, \ad, TASK_THREAD
-	l32i	\ad, \ad, THREAD_CURRENT_DS - TASK_THREAD
-#else
-	l32i	\ad, \ad, THREAD_CURRENT_DS
-#endif
-	.endm
-
-/*
- * set_fs sets current->thread.current_ds to some value.
- * On Entry:
- *	<at>	anything (temp register)
- *	<av>	value to write
- *	<sp>	stack
- * On Exit:
- *	<at>	destroyed (actually, current)
- *	<av>	preserved, value to write
- */
-	.macro	set_fs	at, av, sp
-	GET_CURRENT(\at,\sp)
-	s32i	\av, \at, THREAD_CURRENT_DS
-	.endm
-
-/*
- * kernel_ok determines whether we should bypass addr/size checking.
- * See the equivalent C-macro version below for clarity.
- * On success, kernel_ok branches to a label indicated by parameter
- * <success>.  This implies that the macro falls through to the next
- * insruction on an error.
- *
- * Note that while this macro can be used independently, we designed
- * in for optimal use in the access_ok macro below (i.e., we fall
- * through on error).
- *
- * On Entry:
- * 	<at>		anything (temp register)
- * 	<success>	label to branch to on success; implies
- * 			fall-through macro on error
- * 	<sp>		stack pointer
- * On Exit:
- * 	<at>		destroyed (actually, current->thread.current_ds)
- */
-
-#if ((KERNEL_DS != 0) || (USER_DS == 0))
-# error Assembly macro kernel_ok fails
-#endif
-	.macro	kernel_ok  at, sp, success
-	get_fs	\at, \sp
-	beqz	\at, \success
-	.endm
-
-/*
  * user_ok determines whether the access to user-space memory is allowed.
  * See the equivalent C-macro version below for clarity.
  *
@@ -147,7 +77,6 @@
  * 	<at>	destroyed
  */
 	.macro	access_ok  aa, as, at, sp, error
-	kernel_ok  \at, \sp, .Laccess_ok_\@
 	user_ok    \aa, \as, \at, \error
 .Laccess_ok_\@:
 	.endm
diff --git a/arch/xtensa/include/asm/processor.h b/arch/xtensa/include/asm/processor.h
index 37d3e9887fe7..abad7c3df46f 100644
--- a/arch/xtensa/include/asm/processor.h
+++ b/arch/xtensa/include/asm/processor.h
@@ -152,18 +152,12 @@
  */
 #define SPILL_SLOT_CALL12(sp, reg) (*(((unsigned long *)(sp)) - 16 + (reg)))
 
-typedef struct {
-	unsigned long seg;
-} mm_segment_t;
-
 struct thread_struct {
 
 	/* kernel's return address and stack pointer for context switching */
 	unsigned long ra; /* kernel's a0: return address and window call size */
 	unsigned long sp; /* kernel's a1: stack pointer */
 
-	mm_segment_t current_ds;    /* see uaccess.h for example uses */
-
 	/* struct xtensa_cpuinfo info; */
 
 	unsigned long bad_vaddr; /* last user fault */
@@ -186,7 +180,6 @@ struct thread_struct {
 {									\
 	ra:		0, 						\
 	sp:		sizeof(init_stack) + (long) &init_stack,	\
-	current_ds:	{0},						\
 	/*info:		{0}, */						\
 	bad_vaddr:	0,						\
 	bad_uaddr:	0,						\
diff --git a/arch/xtensa/include/asm/thread_info.h b/arch/xtensa/include/asm/thread_info.h
index a312333a9add..f6fcbba1d02f 100644
--- a/arch/xtensa/include/asm/thread_info.h
+++ b/arch/xtensa/include/asm/thread_info.h
@@ -52,8 +52,6 @@ struct thread_info {
 	__u32			cpu;		/* current CPU */
 	__s32			preempt_count;	/* 0 => preemptable,< 0 => BUG*/
 
-	mm_segment_t		addr_limit;	/* thread address space */
-
 	unsigned long		cpenable;
 #if XCHAL_HAVE_EXCLUSIVE
 	/* result of the most recent exclusive store */
@@ -81,7 +79,6 @@ struct thread_info {
 	.flags		= 0,			\
 	.cpu		= 0,			\
 	.preempt_count	= INIT_PREEMPT_COUNT,	\
-	.addr_limit	= KERNEL_DS,		\
 }
 
 /* how to get the thread information struct from C */
diff --git a/arch/xtensa/include/asm/uaccess.h b/arch/xtensa/include/asm/uaccess.h
index 0edd9e4b23d0..56aec6d504fe 100644
--- a/arch/xtensa/include/asm/uaccess.h
+++ b/arch/xtensa/include/asm/uaccess.h
@@ -19,22 +19,6 @@
 #include <linux/prefetch.h>
 #include <asm/types.h>
 #include <asm/extable.h>
-
-/*
- * The fs value determines whether argument validity checking should
- * be performed or not.  If get_fs() == USER_DS, checking is
- * performed, with get_fs() == KERNEL_DS, checking is bypassed.
- *
- * For historical reasons (Data Segment Register?), these macros are
- * grossly misnamed.
- */
-
-#define KERNEL_DS	((mm_segment_t) { 0 })
-#define USER_DS		((mm_segment_t) { 1 })
-
-#define get_fs()	(current->thread.current_ds)
-#define set_fs(val)	(current->thread.current_ds = (val))
-
 #include <asm-generic/access_ok.h>
 
 /*
diff --git a/arch/xtensa/kernel/asm-offsets.c b/arch/xtensa/kernel/asm-offsets.c
index dc5c83cad9be..f1fd1390d069 100644
--- a/arch/xtensa/kernel/asm-offsets.c
+++ b/arch/xtensa/kernel/asm-offsets.c
@@ -87,7 +87,6 @@ int main(void)
 	OFFSET(TI_STSTUS, thread_info, status);
 	OFFSET(TI_CPU, thread_info, cpu);
 	OFFSET(TI_PRE_COUNT, thread_info, preempt_count);
-	OFFSET(TI_ADDR_LIMIT, thread_info, addr_limit);
 
 	/* struct thread_info (offset from start_struct) */
 	DEFINE(THREAD_RA, offsetof (struct task_struct, thread.ra));
@@ -108,8 +107,6 @@ int main(void)
 #endif
 	DEFINE(THREAD_XTREGS_USER, offsetof (struct thread_info, xtregs_user));
 	DEFINE(XTREGS_USER_SIZE, sizeof(xtregs_user_t));
-	DEFINE(THREAD_CURRENT_DS, offsetof (struct task_struct, \
-	       thread.current_ds));
 
 	/* struct mm_struct */
 	DEFINE(MM_USERS, offsetof(struct mm_struct, mm_users));