s390/uaccess: always run the kernel in home space

Simplify the uaccess code by removing the user_mode=home option.
The kernel will now always run in the home space mode.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

5 files changed, 15 insertions, 35 deletions

diff --git a/arch/s390/include/asm/mmu_context.h b/arch/s390/include/asm/mmu_context.h
index 9f973d8de90e..5d1f950704dc 100644
--- a/arch/s390/include/asm/mmu_context.h
+++ b/arch/s390/include/asm/mmu_context.h
@@ -40,14 +40,8 @@ static inline void update_mm(struct mm_struct *mm, struct task_struct *tsk)
 	pgd_t *pgd = mm->pgd;
 
 	S390_lowcore.user_asce = mm->context.asce_bits | __pa(pgd);
-	if (s390_user_mode != HOME_SPACE_MODE) {
-		/* Load primary space page table origin. */
-		asm volatile(LCTL_OPCODE" 1,1,%0\n"
-			     : : "m" (S390_lowcore.user_asce) );
-	} else
-		/* Load home space page table origin. */
-		asm volatile(LCTL_OPCODE" 13,13,%0"
-			     : : "m" (S390_lowcore.user_asce) );
+	/* Load primary space page table origin. */
+	asm volatile(LCTL_OPCODE" 1,1,%0\n" : : "m" (S390_lowcore.user_asce));
 	set_fs(current->thread.mm_segment);
 }
 
diff --git a/arch/s390/include/asm/processor.h b/arch/s390/include/asm/processor.h
index 50256f05fbcf..3caaf6548ef5 100644
--- a/arch/s390/include/asm/processor.h
+++ b/arch/s390/include/asm/processor.h
@@ -134,14 +134,14 @@ struct stack_frame {
  * Do necessary setup to start up a new thread.
  */
 #define start_thread(regs, new_psw, new_stackp) do {			\
-	regs->psw.mask	= psw_user_bits | PSW_MASK_EA | PSW_MASK_BA;	\
+	regs->psw.mask	= PSW_USER_BITS | PSW_MASK_EA | PSW_MASK_BA;	\
 	regs->psw.addr	= new_psw | PSW_ADDR_AMODE;			\
 	regs->gprs[15]	= new_stackp;					\
 	execve_tail();							\
 } while (0)
 
 #define start_thread31(regs, new_psw, new_stackp) do {			\
-	regs->psw.mask	= psw_user_bits | PSW_MASK_BA;			\
+	regs->psw.mask	= PSW_USER_BITS | PSW_MASK_BA;			\
 	regs->psw.addr	= new_psw | PSW_ADDR_AMODE;			\
 	regs->gprs[15]	= new_stackp;					\
 	__tlb_flush_mm(current->mm);					\
@@ -343,9 +343,9 @@ __set_psw_mask(unsigned long mask)
 }
 
 #define local_mcck_enable() \
-	__set_psw_mask(psw_kernel_bits | PSW_MASK_DAT | PSW_MASK_MCHECK)
+	__set_psw_mask(PSW_KERNEL_BITS | PSW_MASK_DAT | PSW_MASK_MCHECK)
 #define local_mcck_disable() \
-	__set_psw_mask(psw_kernel_bits | PSW_MASK_DAT)
+	__set_psw_mask(PSW_KERNEL_BITS | PSW_MASK_DAT)
 
 /*
  * Basic Machine Check/Program Check Handler.
diff --git a/arch/s390/include/asm/ptrace.h b/arch/s390/include/asm/ptrace.h
index 52b56533c57c..9c82cebddabd 100644
--- a/arch/s390/include/asm/ptrace.h
+++ b/arch/s390/include/asm/ptrace.h
@@ -10,8 +10,11 @@
 
 #ifndef __ASSEMBLY__
 
-extern long psw_kernel_bits;
-extern long psw_user_bits;
+#define PSW_KERNEL_BITS	(PSW_DEFAULT_KEY | PSW_MASK_BASE | PSW_ASC_HOME | \
+			 PSW_MASK_EA | PSW_MASK_BA)
+#define PSW_USER_BITS	(PSW_MASK_DAT | PSW_MASK_IO | PSW_MASK_EXT | \
+			 PSW_DEFAULT_KEY | PSW_MASK_BASE | PSW_MASK_MCHECK | \
+			 PSW_MASK_PSTATE | PSW_ASC_PRIMARY)
 
 /*
  * The pt_regs struct defines the way the registers are stored on
diff --git a/arch/s390/include/asm/setup.h b/arch/s390/include/asm/setup.h
index 59880dbaf360..df802ee14af6 100644
--- a/arch/s390/include/asm/setup.h
+++ b/arch/s390/include/asm/setup.h
@@ -48,13 +48,6 @@ void detect_memory_layout(struct mem_chunk chunk[], unsigned long maxsize);
 void create_mem_hole(struct mem_chunk mem_chunk[], unsigned long addr,
 		     unsigned long size);
 
-#define PRIMARY_SPACE_MODE	0
-#define ACCESS_REGISTER_MODE	1
-#define SECONDARY_SPACE_MODE	2
-#define HOME_SPACE_MODE		3
-
-extern unsigned int s390_user_mode;
-
 /*
  * Machine features detected in head.S
  */
diff --git a/arch/s390/include/asm/uaccess.h b/arch/s390/include/asm/uaccess.h
index 9c33ed4e666f..79330af9a5f8 100644
--- a/arch/s390/include/asm/uaccess.h
+++ b/arch/s390/include/asm/uaccess.h
@@ -94,9 +94,7 @@ static inline unsigned long extable_fixup(const struct exception_table_entry *x)
 
 struct uaccess_ops {
 	size_t (*copy_from_user)(size_t, const void __user *, void *);
-	size_t (*copy_from_user_small)(size_t, const void __user *, void *);
 	size_t (*copy_to_user)(size_t, void __user *, const void *);
-	size_t (*copy_to_user_small)(size_t, void __user *, const void *);
 	size_t (*copy_in_user)(size_t, void __user *, const void __user *);
 	size_t (*clear_user)(size_t, void __user *);
 	size_t (*strnlen_user)(size_t, const char __user *);
@@ -106,22 +104,20 @@ struct uaccess_ops {
 };
 
 extern struct uaccess_ops uaccess;
-extern struct uaccess_ops uaccess_std;
 extern struct uaccess_ops uaccess_mvcos;
-extern struct uaccess_ops uaccess_mvcos_switch;
 extern struct uaccess_ops uaccess_pt;
 
 extern int __handle_fault(unsigned long, unsigned long, int);
 
 static inline int __put_user_fn(size_t size, void __user *ptr, void *x)
 {
-	size = uaccess.copy_to_user_small(size, ptr, x);
+	size = uaccess.copy_to_user(size, ptr, x);
 	return size ? -EFAULT : size;
 }
 
 static inline int __get_user_fn(size_t size, const void __user *ptr, void *x)
 {
-	size = uaccess.copy_from_user_small(size, ptr, x);
+	size = uaccess.copy_from_user(size, ptr, x);
 	return size ? -EFAULT : size;
 }
 
@@ -226,10 +222,7 @@ extern int __get_user_bad(void) __attribute__((noreturn));
 static inline unsigned long __must_check
 __copy_to_user(void __user *to, const void *from, unsigned long n)
 {
-	if (__builtin_constant_p(n) && (n <= 256))
-		return uaccess.copy_to_user_small(n, to, from);
-	else
-		return uaccess.copy_to_user(n, to, from);
+	return uaccess.copy_to_user(n, to, from);
 }
 
 #define __copy_to_user_inatomic __copy_to_user
@@ -275,10 +268,7 @@ copy_to_user(void __user *to, const void *from, unsigned long n)
 static inline unsigned long __must_check
 __copy_from_user(void *to, const void __user *from, unsigned long n)
 {
-	if (__builtin_constant_p(n) && (n <= 256))
-		return uaccess.copy_from_user_small(n, from, to);
-	else
-		return uaccess.copy_from_user(n, from, to);
+	return uaccess.copy_from_user(n, from, to);
 }
 
 extern void copy_from_user_overflow(void)