LoongArch: Fix the !CONFIG_SMP build

1, We assume arch/loongarch/include/asm/smp.h be included in include/
   linux/smp.h is valid and the reverse inclusion isn't. So remove the
   <linux/smp.h> in arch/loongarch/include/asm/smp.h.
2, arch/loongarch/include/asm/smp.h is only needed when CONFIG_SMP,
   and setup.c include it only because it need plat_smp_setup(). So,
   reorganize setup.c & smp.h, and then remove <asm/smp.h> in setup.c.
3, Fix cacheinfo.c and percpu.h build error by adding the missing header
   files when !CONFIG_SMP.
4, Fix acpi.c build error by adding CONFIG_SMP guards.
5, Move irq_stat definition from smp.c to irq.c and fix its declaration.
6, Select CONFIG_SMP for CONFIG_NUMA, similar as other architectures do.
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

arch/loongarch/Kconfig

@@ -343,6 +343,7 @@ config NR_CPUS
 
 config NUMA
 	bool "NUMA Support"
+	select SMP
 	select ACPI_NUMA if ACPI
 	help
 	  Say Y to compile the kernel with NUMA (Non-Uniform Memory Access)

arch/loongarch/include/asm/hardirq.h

@@ -19,7 +19,7 @@ typedef struct {
 	unsigned int __softirq_pending;
 } ____cacheline_aligned irq_cpustat_t;
 
-DECLARE_PER_CPU_ALIGNED(irq_cpustat_t, irq_stat);
+DECLARE_PER_CPU_SHARED_ALIGNED(irq_cpustat_t, irq_stat);
 
 #define __ARCH_IRQ_STAT
 

arch/loongarch/include/asm/percpu.h

@@ -6,6 +6,7 @@
 #define __ASM_PERCPU_H
 
 #include <asm/cmpxchg.h>
+#include <asm/loongarch.h>
 
 /* Use r21 for fast access */
 register unsigned long __my_cpu_offset __asm__("$r21");

arch/loongarch/include/asm/smp.h

@@ -9,10 +9,16 @@
 #include <linux/atomic.h>
 #include <linux/bitops.h>
 #include <linux/linkage.h>
-#include <linux/smp.h>
 #include <linux/threads.h>
 #include <linux/cpumask.h>
 
+extern int smp_num_siblings;
+extern int num_processors;
+extern int disabled_cpus;
+extern cpumask_t cpu_sibling_map[];
+extern cpumask_t cpu_core_map[];
+extern cpumask_t cpu_foreign_map[];
+
 void loongson3_smp_setup(void);
 void loongson3_prepare_cpus(unsigned int max_cpus);
 void loongson3_boot_secondary(int cpu, struct task_struct *idle);
@@ -25,26 +31,11 @@ int loongson3_cpu_disable(void);
 void loongson3_cpu_die(unsigned int cpu);
 #endif
 
-#ifdef CONFIG_SMP
-
 static inline void plat_smp_setup(void)
 {
 	loongson3_smp_setup();
 }
 
-#else /* !CONFIG_SMP */
-
-static inline void plat_smp_setup(void) { }
-
-#endif /* !CONFIG_SMP */
-
-extern int smp_num_siblings;
-extern int num_processors;
-extern int disabled_cpus;
-extern cpumask_t cpu_sibling_map[];
-extern cpumask_t cpu_core_map[];
-extern cpumask_t cpu_foreign_map[];
-
 static inline int raw_smp_processor_id(void)
 {
 #if defined(__VDSO__)

arch/loongarch/kernel/acpi.c

@@ -138,6 +138,7 @@ void __init acpi_boot_table_init(void)
 	}
 }
 
+#ifdef CONFIG_SMP
 static int set_processor_mask(u32 id, u32 flags)
 {
 
@@ -166,15 +167,18 @@ static int set_processor_mask(u32 id, u32 flags)
 
 	return cpu;
 }
+#endif
 
 static void __init acpi_process_madt(void)
 {
+#ifdef CONFIG_SMP
 	int i;
 
 	for (i = 0; i < NR_CPUS; i++) {
 		__cpu_number_map[i] = -1;
 		__cpu_logical_map[i] = -1;
 	}
+#endif
 
 	loongson_sysconf.nr_cpus = num_processors;
 }

arch/loongarch/kernel/cacheinfo.c

@@ -4,6 +4,7 @@
  *
  * Copyright (C) 2020-2022 Loongson Technology Corporation Limited
  */
+#include <asm/cpu-info.h>
 #include <linux/cacheinfo.h>
 
 /* Populates leaf and increments to next leaf */

arch/loongarch/kernel/irq.c

@@ -22,6 +22,8 @@
 #include <asm/setup.h>
 
 DEFINE_PER_CPU(unsigned long, irq_stack);
+DEFINE_PER_CPU_SHARED_ALIGNED(irq_cpustat_t, irq_stat);
+EXPORT_PER_CPU_SYMBOL(irq_stat);
 
 struct irq_domain *cpu_domain;
 struct irq_domain *liointc_domain;
@@ -56,8 +58,11 @@ int arch_show_interrupts(struct seq_file *p, int prec)
 
 void __init init_IRQ(void)
 {
-	int i, r, ipi_irq;
+	int i;
+#ifdef CONFIG_SMP
+	int r, ipi_irq;
 	static int ipi_dummy_dev;
+#endif
 	unsigned int order = get_order(IRQ_STACK_SIZE);
 	struct page *page;
 

arch/loongarch/kernel/setup.c

@@ -39,7 +39,6 @@
 #include <asm/pgalloc.h>
 #include <asm/sections.h>
 #include <asm/setup.h>
-#include <asm/smp.h>
 #include <asm/time.h>
 
 #define SMBIOS_BIOSSIZE_OFFSET		0x09
@@ -349,8 +348,6 @@ static void __init prefill_possible_map(void)
 
 	nr_cpu_ids = possible;
 }
-#else
-static inline void prefill_possible_map(void) {}
 #endif
 
 void __init setup_arch(char **cmdline_p)
@@ -367,8 +364,10 @@ void __init setup_arch(char **cmdline_p)
 	arch_mem_init(cmdline_p);
 
 	resource_init();
+#ifdef CONFIG_SMP
 	plat_smp_setup();
 	prefill_possible_map();
+#endif
 
 	paging_init();
 }

arch/loongarch/kernel/smp.c

@@ -66,8 +66,6 @@ static cpumask_t cpu_core_setup_map;
 
 struct secondary_data cpuboot_data;
 static DEFINE_PER_CPU(int, cpu_state);
-DEFINE_PER_CPU_SHARED_ALIGNED(irq_cpustat_t, irq_stat);
-EXPORT_PER_CPU_SYMBOL(irq_stat);
 
 enum ipi_msg_type {
 	IPI_RESCHEDULE,