s390/fpu: remove regs member from struct fpu

KVM was the only user which modified the regs pointer in struct fpu. Remove
the pointer and convert the rest of the core fpu code to directly access
the save area embedded within struct fpu.

Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>

arch/s390/include/asm/fpu-types.h

@@ -13,7 +13,6 @@
 
 struct fpu {
 	__u32 fpc;		/* Floating-point control */
-	void *regs;		/* Pointer to the current save area */
 	union {
 		/* Floating-point register save area */
 		freg_t fprs[__NUM_FPRS];

arch/s390/include/asm/processor.h

@@ -202,7 +202,6 @@ typedef struct thread_struct thread_struct;
 
 #define INIT_THREAD {							\
 	.ksp = sizeof(init_stack) + (unsigned long) &init_stack,	\
-	.ufpu.regs = (void *)init_task.thread.ufpu.fprs,		\
 	.last_break = 1,						\
 }
 

arch/s390/kernel/fpu.c

@@ -110,13 +110,12 @@ EXPORT_SYMBOL(__kernel_fpu_end);
 void __load_user_fpu_regs(void)
 {
 	struct fpu *state = &current->thread.ufpu;
-	void *regs = current->thread.ufpu.regs;
 
 	fpu_lfpc_safe(&state->fpc);
 	if (likely(cpu_has_vx()))
-		load_vx_regs(regs);
+		load_vx_regs(state->vxrs);
 	else
-		load_fp_regs(regs);
+		load_fp_regs(state->fprs);
 	clear_thread_flag(TIF_FPU);
 }
 
@@ -132,21 +131,19 @@ void save_user_fpu_regs(void)
 {
 	unsigned long flags;
 	struct fpu *state;
-	void *regs;
 
 	local_irq_save(flags);
 
 	if (test_thread_flag(TIF_FPU))
 		goto out;
 
 	state = &current->thread.ufpu;
-	regs = current->thread.ufpu.regs;
 
 	fpu_stfpc(&state->fpc);
 	if (likely(cpu_has_vx()))
-		save_vx_regs(regs);
+		save_vx_regs(state->vxrs);
 	else
-		save_fp_regs(regs);
+		save_fp_regs(state->fprs);
 	set_thread_flag(TIF_FPU);
 out:
 	local_irq_restore(flags);

arch/s390/kernel/process.c

@@ -94,7 +94,6 @@ int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
 	save_user_fpu_regs();
 
 	*dst = *src;
-	dst->thread.ufpu.regs = dst->thread.ufpu.fprs;
 	dst->thread.kfpu_flags = 0;
 
 	/*