[PATCH v3] mips: DEC: honor CONFIG_MIPS_FP_SUPPORT=n

[Randy Dunlap]

Include the DECstation interrupt handler in opting out of
FPU support.

Fixes a linker error:

mips-linux-ld: arch/mips/dec/int-handler.o: in function `fpu':
(.text+0x148): undefined reference to `handle_fpe_int'

Fixes: 183b40f992c8 ("MIPS: Allow FP support to be disabled")
Signed-off-by: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
Reported-by: kernel test robot <lkp@xxxxxxxxx>
Cc: Paul Burton <paulburton@xxxxxxxxxx>
Cc: Thomas Bogendoerfer <tsbogend@xxxxxxxxxxxxxxxx>
Cc: Maciej W. Rozycki <macro@xxxxxxxxxxx>
Cc: linux-mips@xxxxxxxxxxxxxxx
---
v2: add another ifdef block in int-handler.S; (Maciej)
    add an ifdef block in dec/setup.c; (Maciej)
v3: use IS_ENABLED() instead of an ifdef block in dec/setup.c; (Maciej)

 arch/mips/dec/int-handler.S |    6 +++---
 arch/mips/dec/setup.c       |    3 ++-
 2 files changed, 5 insertions(+), 4 deletions(-)

--- linux-next-20220303.orig/arch/mips/dec/int-handler.S
+++ linux-next-20220303/arch/mips/dec/int-handler.S
@@ -131,7 +131,7 @@
 		 */
 		mfc0	t0,CP0_CAUSE		# get pending interrupts
 		mfc0	t1,CP0_STATUS
-#ifdef CONFIG_32BIT
+#if defined(CONFIG_32BIT) && defined(CONFIG_MIPS_FP_SUPPORT)
 		lw	t2,cpu_fpu_mask
 #endif
 		andi	t0,ST0_IM		# CAUSE.CE may be non-zero!
@@ -139,7 +139,7 @@
 
 		beqz	t0,spurious
 
-#ifdef CONFIG_32BIT
+#if defined(CONFIG_32BIT) && defined(CONFIG_MIPS_FP_SUPPORT)
 		 and	t2,t0
 		bnez	t2,fpu			# handle FPU immediately
 #endif
@@ -280,7 +280,7 @@ handle_it:
 		j	dec_irq_dispatch
 		 nop
 
-#ifdef CONFIG_32BIT
+#if defined(CONFIG_32BIT) && defined(CONFIG_MIPS_FP_SUPPORT)
 fpu:
 		lw	t0,fpu_kstat_irq
 		nop
--- linux-next-20220303.orig/arch/mips/dec/setup.c
+++ linux-next-20220303/arch/mips/dec/setup.c
@@ -746,7 +746,8 @@ void __init arch_init_irq(void)
 		dec_interrupt[DEC_IRQ_HALT] = -1;
 
 	/* Register board interrupts: FPU and cascade. */
-	if (dec_interrupt[DEC_IRQ_FPU] >= 0 && cpu_has_fpu) {
+	if (IS_ENABLED(CONFIG_MIPS_FP_SUPPORT) &&
+	    dec_interrupt[DEC_IRQ_FPU] >= 0 && cpu_has_fpu) {
 		struct irq_desc *desc_fpu;
 		int irq_fpu;