MIPS: Move r4k FP code from r4k_switch.S to r4k_fpu.S

Move _save_fp(), _restore_fp(), _save_msa(), _restore_msa(),
_init_msa_upper() & _init_fpu() out of r4k_switch.S & into r4k_fpu.S.
This allows us to clean up the way in which Octeon includes the default
r4k implementations of these FP functions despite replacing resume(),
and makes CONFIG_R4K_FPU more straightforwardly represent all
configurations that have an R4K-style FPU, including Octeon.

Besides cleaning up this will be useful for later patches which disable
FP support.

[ralf@linux-mips.org: Fixed build issues reported by Arnd Bergmann
<arnd@arndb.de>]

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/16237/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/Kconfig

@@ -2241,7 +2241,7 @@ config CPU_GENERIC_DUMP_TLB
 
 config CPU_R4K_FPU
 	bool
-	default y if !(CPU_R3000 || CPU_TX39XX || CPU_CAVIUM_OCTEON)
+	default y if !(CPU_R3000 || CPU_TX39XX)
 
 config CPU_R4K_CACHE_TLB
 	bool

arch/mips/kernel/Makefile

@@ -35,10 +35,15 @@ obj-$(CONFIG_MODULES)		+= module.o
 obj-$(CONFIG_FTRACE_SYSCALLS)	+= ftrace.o
 obj-$(CONFIG_FUNCTION_TRACER)	+= mcount.o ftrace.o
 
-obj-$(CONFIG_CPU_R4K_FPU)	+= r4k_fpu.o r4k_switch.o
-obj-$(CONFIG_CPU_R3000)		+= r2300_fpu.o r2300_switch.o
-obj-$(CONFIG_CPU_TX39XX)	+= r2300_fpu.o r2300_switch.o
-obj-$(CONFIG_CPU_CAVIUM_OCTEON)	+= r4k_fpu.o octeon_switch.o
+sw-y				:= r4k_switch.o
+sw-$(CONFIG_CPU_R3000)		:= r2300_switch.o
+sw-$(CONFIG_CPU_TX39XX)		:= r2300_switch.o
+sw-$(CONFIG_CPU_CAVIUM_OCTEON)	:= octeon_switch.o
+obj-y				+= $(sw-y)
+
+obj-$(CONFIG_CPU_R4K_FPU)	+= r4k_fpu.o
+obj-$(CONFIG_CPU_R3000)		+= r2300_fpu.o
+obj-$(CONFIG_CPU_TX39XX)	+= r2300_fpu.o
 
 obj-$(CONFIG_SMP)		+= smp.o
 obj-$(CONFIG_SMP_UP)		+= smp-up.o

arch/mips/kernel/octeon_switch.S

@@ -10,12 +10,13 @@
  * Copyright (C) 2000 MIPS Technologies, Inc.
  *    written by Carsten Langgaard, carstenl@mips.com
  */
+#include <asm/asm.h>
+#include <asm/export.h>
+#include <asm/asm-offsets.h>
+#include <asm/mipsregs.h>
+#include <asm/regdef.h>
+#include <asm/stackframe.h>
 
-#define USE_ALTERNATE_RESUME_IMPL 1
-	.set push
-	.set arch=mips64r2
-#include "r4k_switch.S"
-	.set pop
 /*
  * task_struct *resume(task_struct *prev, task_struct *next,
  *		       struct thread_info *next_ti)

arch/mips/kernel/r4k_fpu.S

@@ -15,6 +15,7 @@
 #include <asm/asm.h>
 #include <asm/asmmacro.h>
 #include <asm/errno.h>
+#include <asm/export.h>
 #include <asm/fpregdef.h>
 #include <asm/mipsregs.h>
 #include <asm/asm-offsets.h>
@@ -34,6 +35,201 @@
 	.previous
 	.endm
 
+/*
+ * Save a thread's fp context.
+ */
+LEAF(_save_fp)
+EXPORT_SYMBOL(_save_fp)
+#if defined(CONFIG_64BIT) || defined(CONFIG_CPU_MIPS32_R2) || \
+		defined(CONFIG_CPU_MIPS32_R6)
+	mfc0	t0, CP0_STATUS
+#endif
+	fpu_save_double a0 t0 t1		# clobbers t1
+	jr	ra
+	END(_save_fp)
+
+/*
+ * Restore a thread's fp context.
+ */
+LEAF(_restore_fp)
+#if defined(CONFIG_64BIT) || defined(CONFIG_CPU_MIPS32_R2) || \
+		defined(CONFIG_CPU_MIPS32_R6)
+	mfc0	t0, CP0_STATUS
+#endif
+	fpu_restore_double a0 t0 t1		# clobbers t1
+	jr	ra
+	END(_restore_fp)
+
+#ifdef CONFIG_CPU_HAS_MSA
+
+/*
+ * Save a thread's MSA vector context.
+ */
+LEAF(_save_msa)
+EXPORT_SYMBOL(_save_msa)
+	msa_save_all	a0
+	jr	ra
+	END(_save_msa)
+
+/*
+ * Restore a thread's MSA vector context.
+ */
+LEAF(_restore_msa)
+	msa_restore_all	a0
+	jr	ra
+	END(_restore_msa)
+
+LEAF(_init_msa_upper)
+	msa_init_all_upper
+	jr	ra
+	END(_init_msa_upper)
+
+#endif
+
+/*
+ * Load the FPU with signalling NANS.  This bit pattern we're using has
+ * the property that no matter whether considered as single or as double
+ * precision represents signaling NANS.
+ *
+ * The value to initialize fcr31 to comes in $a0.
+ */
+
+	.set push
+	SET_HARDFLOAT
+
+LEAF(_init_fpu)
+	mfc0	t0, CP0_STATUS
+	li	t1, ST0_CU1
+	or	t0, t1
+	mtc0	t0, CP0_STATUS
+	enable_fpu_hazard
+
+	ctc1	a0, fcr31
+
+	li	t1, -1				# SNaN
+
+#ifdef CONFIG_64BIT
+	sll	t0, t0, 5
+	bgez	t0, 1f				# 16 / 32 register mode?
+
+	dmtc1	t1, $f1
+	dmtc1	t1, $f3
+	dmtc1	t1, $f5
+	dmtc1	t1, $f7
+	dmtc1	t1, $f9
+	dmtc1	t1, $f11
+	dmtc1	t1, $f13
+	dmtc1	t1, $f15
+	dmtc1	t1, $f17
+	dmtc1	t1, $f19
+	dmtc1	t1, $f21
+	dmtc1	t1, $f23
+	dmtc1	t1, $f25
+	dmtc1	t1, $f27
+	dmtc1	t1, $f29
+	dmtc1	t1, $f31
+1:
+#endif
+
+#ifdef CONFIG_CPU_MIPS32
+	mtc1	t1, $f0
+	mtc1	t1, $f1
+	mtc1	t1, $f2
+	mtc1	t1, $f3
+	mtc1	t1, $f4
+	mtc1	t1, $f5
+	mtc1	t1, $f6
+	mtc1	t1, $f7
+	mtc1	t1, $f8
+	mtc1	t1, $f9
+	mtc1	t1, $f10
+	mtc1	t1, $f11
+	mtc1	t1, $f12
+	mtc1	t1, $f13
+	mtc1	t1, $f14
+	mtc1	t1, $f15
+	mtc1	t1, $f16
+	mtc1	t1, $f17
+	mtc1	t1, $f18
+	mtc1	t1, $f19
+	mtc1	t1, $f20
+	mtc1	t1, $f21
+	mtc1	t1, $f22
+	mtc1	t1, $f23
+	mtc1	t1, $f24
+	mtc1	t1, $f25
+	mtc1	t1, $f26
+	mtc1	t1, $f27
+	mtc1	t1, $f28
+	mtc1	t1, $f29
+	mtc1	t1, $f30
+	mtc1	t1, $f31
+
+#if defined(CONFIG_CPU_MIPS32_R2) || defined(CONFIG_CPU_MIPS32_R6)
+	.set    push
+	.set    MIPS_ISA_LEVEL_RAW
+	.set	fp=64
+	sll     t0, t0, 5			# is Status.FR set?
+	bgez    t0, 1f				# no: skip setting upper 32b
+
+	mthc1   t1, $f0
+	mthc1   t1, $f1
+	mthc1   t1, $f2
+	mthc1   t1, $f3
+	mthc1   t1, $f4
+	mthc1   t1, $f5
+	mthc1   t1, $f6
+	mthc1   t1, $f7
+	mthc1   t1, $f8
+	mthc1   t1, $f9
+	mthc1   t1, $f10
+	mthc1   t1, $f11
+	mthc1   t1, $f12
+	mthc1   t1, $f13
+	mthc1   t1, $f14
+	mthc1   t1, $f15
+	mthc1   t1, $f16
+	mthc1   t1, $f17
+	mthc1   t1, $f18
+	mthc1   t1, $f19
+	mthc1   t1, $f20
+	mthc1   t1, $f21
+	mthc1   t1, $f22
+	mthc1   t1, $f23
+	mthc1   t1, $f24
+	mthc1   t1, $f25
+	mthc1   t1, $f26
+	mthc1   t1, $f27
+	mthc1   t1, $f28
+	mthc1   t1, $f29
+	mthc1   t1, $f30
+	mthc1   t1, $f31
+1:	.set    pop
+#endif /* CONFIG_CPU_MIPS32_R2 || CONFIG_CPU_MIPS32_R6 */
+#else
+	.set	MIPS_ISA_ARCH_LEVEL_RAW
+	dmtc1	t1, $f0
+	dmtc1	t1, $f2
+	dmtc1	t1, $f4
+	dmtc1	t1, $f6
+	dmtc1	t1, $f8
+	dmtc1	t1, $f10
+	dmtc1	t1, $f12
+	dmtc1	t1, $f14
+	dmtc1	t1, $f16
+	dmtc1	t1, $f18
+	dmtc1	t1, $f20
+	dmtc1	t1, $f22
+	dmtc1	t1, $f24
+	dmtc1	t1, $f26
+	dmtc1	t1, $f28
+	dmtc1	t1, $f30
+#endif
+	jr	ra
+	END(_init_fpu)
+
+	.set pop	/* SET_HARDFLOAT */
+
 	.set	noreorder
 
 /**