locking, arch/ia64: Reduce <asm/smp.h> header dependencies by moving XTP bits into the new <asm/xtp.h> header

We want to remove the #include <asm/io.h> from <asm/smp.h>, but for this
we have to move the XTP bits into a separate header first (as these bits
rely on <asm/io.h> definitions), and include them in the .c files that rely
on those APIs.

Co-developed-by: Ingo Molnar <[e-mail]>
Signed-off-by: Peter Zijlstra <[e-mail]>
Signed-off-by: Ingo Molnar <[e-mail]>

arch/ia64/include/asm/smp.h

···
 #include <linux/bitops.h>
 #include <linux/irqreturn.h>
 
-#include <asm/io.h>
 #include <asm/param.h>
 #include <asm/processor.h>
 #include <asm/ptrace.h>
···
 
 #ifdef CONFIG_SMP
 
-#define XTP_OFFSET		0x1e0008
-
-#define SMP_IRQ_REDIRECTION	(1 << 0)
-#define SMP_IPI_REDIRECTION	(1 << 1)
-
 #define raw_smp_processor_id() (current_thread_info()->cpu)
 
 extern struct smp_boot_data {
···
 DECLARE_PER_CPU_SHARED_ALIGNED(cpumask_t, cpu_sibling_map);
 extern int smp_num_siblings;
 extern void __iomem *ipi_base_addr;
-extern unsigned char smp_int_redirect;
 
 extern volatile int ia64_cpu_to_sapicid[];
 #define cpu_physical_id(i)	ia64_cpu_to_sapicid[i]
···
 		if (cpu_physical_id(i) == cpuid)
 			break;
 	return i;
-}
-
-/*
- * XTP control functions:
- *	min_xtp   : route all interrupts to this CPU
- *	normal_xtp: nominal XTP value
- *	max_xtp   : never deliver interrupts to this CPU.
- */
-
-static inline void
-min_xtp (void)
-{
-	if (smp_int_redirect & SMP_IRQ_REDIRECTION)
-		writeb(0x00, ipi_base_addr + XTP_OFFSET); /* XTP to min */
-}
-
-static inline void
-normal_xtp (void)
-{
-	if (smp_int_redirect & SMP_IRQ_REDIRECTION)
-		writeb(0x08, ipi_base_addr + XTP_OFFSET); /* XTP normal */
-}
-
-static inline void
-max_xtp (void)
-{
-	if (smp_int_redirect & SMP_IRQ_REDIRECTION)
-		writeb(0x0f, ipi_base_addr + XTP_OFFSET); /* Set XTP to max */
 }
 
 /* Upping and downing of CPUs */

arch/ia64/include/asm/xtp.h

···
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_IA64_XTP_H
+#define _ASM_IA64_XTP_H
+
+#include <asm/io.h>
+
+#ifdef CONFIG_SMP
+
+#define XTP_OFFSET		0x1e0008
+
+#define SMP_IRQ_REDIRECTION	(1 << 0)
+#define SMP_IPI_REDIRECTION	(1 << 1)
+
+extern unsigned char smp_int_redirect;
+
+/*
+ * XTP control functions:
+ *	min_xtp   : route all interrupts to this CPU
+ *	normal_xtp: nominal XTP value
+ *	max_xtp   : never deliver interrupts to this CPU.
+ */
+
+static inline void
+min_xtp (void)
+{
+	if (smp_int_redirect & SMP_IRQ_REDIRECTION)
+		writeb(0x00, ipi_base_addr + XTP_OFFSET); /* XTP to min */
+}
+
+static inline void
+normal_xtp (void)
+{
+	if (smp_int_redirect & SMP_IRQ_REDIRECTION)
+		writeb(0x08, ipi_base_addr + XTP_OFFSET); /* XTP normal */
+}
+
+static inline void
+max_xtp (void)
+{
+	if (smp_int_redirect & SMP_IRQ_REDIRECTION)
+		writeb(0x0f, ipi_base_addr + XTP_OFFSET); /* Set XTP to max */
+}
+
+#endif /* CONFIG_SMP */
+
+#endif /* _ASM_IA64_XTP_Hy */

arch/ia64/kernel/iosapic.c

···
 #include <asm/iosapic.h>
 #include <asm/processor.h>
 #include <asm/ptrace.h>
+#include <asm/xtp.h>
 
 #undef DEBUG_INTERRUPT_ROUTING
 

arch/ia64/kernel/irq.c

···
 #include <linux/kernel_stat.h>
 
 #include <asm/mca.h>
+#include <asm/xtp.h>
 
 /*
  * 'what should we do if we get a hw irq event on an illegal vector'.

arch/ia64/kernel/process.c

···
 #include <linux/uaccess.h>
 #include <asm/unwind.h>
 #include <asm/user.h>
+#include <asm/xtp.h>
 
 #include "entry.h"
 

arch/ia64/kernel/sal.c

···
 #include <asm/page.h>
 #include <asm/sal.h>
 #include <asm/pal.h>
+#include <asm/xtp.h>
 
  __cacheline_aligned DEFINE_SPINLOCK(sal_lock);
 unsigned long sal_platform_features;

arch/ia64/kernel/setup.c

···
 #include <asm/tlbflush.h>
 #include <asm/unistd.h>
 #include <asm/uv/uv.h>
+#include <asm/xtp.h>
 
 #if defined(CONFIG_SMP) && (IA64_CPU_SIZE > PAGE_SIZE)
 # error "struct cpuinfo_ia64 too big!"

arch/ia64/kernel/smp.c

···
 #include <asm/tlbflush.h>
 #include <asm/unistd.h>
 #include <asm/mca.h>
+#include <asm/xtp.h>
 
 /*
  * Note: alignment of 4 entries/cacheline was empirically determined

arch/parisc/include/asm/timex.h

···
 #ifndef _ASMPARISC_TIMEX_H
 #define _ASMPARISC_TIMEX_H
 
+#include <asm/special_insns.h>
 
 #define CLOCK_TICK_RATE	1193180 /* Underlying HZ */