parisc: Enable -mlong-calls gcc option by default when !CONFIG_MODULES

When building a kernel without module support, the CONFIG_MLONGCALL option
needs to be enabled in order to reach symbols which are outside of a 22-bit
branch.

This patch changes the autodetection in the Kconfig script to always enable
CONFIG_MLONGCALL when modules are disabled and uses a far call to
preempt_schedule_irq() in intr_do_preempt() to reach the symbol in all cases.

Signed-off-by: Helge Deller <deller@gmx.de>
Reported-by: kernel test robot <lkp@intel.com>
Cc: stable@vger.kernel.org # v5.6+

arch/parisc/Kconfig

@@ -202,9 +202,8 @@ config PREFETCH
 	depends on PA8X00 || PA7200
 
 config MLONGCALLS
-	bool "Enable the -mlong-calls compiler option for big kernels"
-	default y if !MODULES || UBSAN || FTRACE
-	default n
+	def_bool y if !MODULES || UBSAN || FTRACE
+	bool "Enable the -mlong-calls compiler option for big kernels" if MODULES && !UBSAN && !FTRACE
 	depends on PA8X00
 	help
 	  If you configure the kernel to include many drivers built-in instead

arch/parisc/kernel/entry.S

@@ -997,10 +997,17 @@ intr_do_preempt:
 	bb,<,n	%r20, 31 - PSW_SM_I, intr_restore
 	nop
 
+	/* ssm PSW_SM_I done later in intr_restore */
+#ifdef CONFIG_MLONGCALLS
+	ldil	L%intr_restore, %r2
+	load32	preempt_schedule_irq, %r1
+	bv	%r0(%r1)
+	ldo	R%intr_restore(%r2), %r2
+#else
+	ldil	L%intr_restore, %r1
 	BL	preempt_schedule_irq, %r2
-	nop
-
-	b,n	intr_restore		/* ssm PSW_SM_I done by intr_restore */
+	ldo	R%intr_restore(%r1), %r2
+#endif
 #endif /* CONFIG_PREEMPTION */
 
 	/*