MIPS: Remove struct task_struct fpu state when CONFIG_MIPS_FP_SUPPORT=n

When CONFIG_MIPS_FP_SUPPORT=n we don't support floating point & so don't
need to preserve floating point context for tasks. Remove that context
from struct task_struct.

Signed-off-by: Paul Burton <paul.burton@mips.com>
Patchwork: https://patchwork.linux-mips.org/patch/21013/
Cc: linux-mips@linux-mips.org

arch/mips/include/asm/processor.h

@@ -255,8 +255,10 @@ struct thread_struct {
 	/* Saved cp0 stuff. */
 	unsigned long cp0_status;
 
+#ifdef CONFIG_MIPS_FP_SUPPORT
 	/* Saved fpu/fpu emulator stuff. */
 	struct mips_fpu_struct fpu FPU_ALIGN;
+#endif
 	/* Assigned branch delay slot 'emulation' frame */
 	atomic_t bd_emu_frame;
 	/* PC of the branch from a branch delay slot 'emulation' */
@@ -299,6 +301,17 @@ struct thread_struct {
 #define FPAFF_INIT
 #endif /* CONFIG_MIPS_MT_FPAFF */
 
+#ifdef CONFIG_MIPS_FP_SUPPORT
+# define FPU_INIT						\
+	.fpu			= {				\
+		.fpr		= {{{0,},},},			\
+		.fcr31		= 0,				\
+		.msacsr		= 0,				\
+	},
+#else
+# define FPU_INIT
+#endif
+
 #define INIT_THREAD  {						\
 	/*							\
 	 * Saved main processor registers			\
@@ -321,11 +334,7 @@ struct thread_struct {
 	/*							\
 	 * Saved FPU/FPU emulator stuff				\
 	 */							\
-	.fpu			= {				\
-		.fpr		= {{{0,},},},			\
-		.fcr31		= 0,				\
-		.msacsr		= 0,				\
-	},							\
+	FPU_INIT						\
 	/*							\
 	 * FPU affinity state (null if not FPAFF)		\
 	 */							\

arch/mips/kernel/asm-offsets.c

@@ -123,7 +123,6 @@ void output_thread_defines(void)
 	OFFSET(THREAD_REG31, task_struct, thread.reg31);
 	OFFSET(THREAD_STATUS, task_struct,
 	       thread.cp0_status);
-	OFFSET(THREAD_FPU, task_struct, thread.fpu);
 
 	OFFSET(THREAD_BVADDR, task_struct, \
 	       thread.cp0_badvaddr);
@@ -135,8 +134,11 @@ void output_thread_defines(void)
 	BLANK();
 }
 
+#ifdef CONFIG_MIPS_FP_SUPPORT
 void output_thread_fpu_defines(void)
 {
+	OFFSET(THREAD_FPU, task_struct, thread.fpu);
+
 	OFFSET(THREAD_FPR0, task_struct, thread.fpu.fpr[0]);
 	OFFSET(THREAD_FPR1, task_struct, thread.fpu.fpr[1]);
 	OFFSET(THREAD_FPR2, task_struct, thread.fpu.fpr[2]);
@@ -174,6 +176,7 @@ void output_thread_fpu_defines(void)
 	OFFSET(THREAD_MSA_CSR, task_struct, thread.fpu.msacsr);
 	BLANK();
 }
+#endif
 
 void output_mm_defines(void)
 {
@@ -341,6 +344,7 @@ void output_pm_defines(void)
 }
 #endif
 
+#ifdef CONFIG_MIPS_FP_SUPPORT
 void output_kvm_defines(void)
 {
 	COMMENT(" KVM/MIPS Specific offsets. ");
@@ -382,6 +386,7 @@ void output_kvm_defines(void)
 	OFFSET(VCPU_MSA_CSR, kvm_vcpu_arch, fpu.msacsr);
 	BLANK();
 }
+#endif
 
 #ifdef CONFIG_MIPS_CPS
 void output_cps_defines(void)