MIPS: Allow __cpu_number_map to be larger than NR_CPUS

In systems where the CPU id space is sparse, this allows a smaller
NR_CPUS to be chosen, thus keeping internal data structures smaller.
Signed-off-by: David Daney <david.daney@cavium.com>
Signed-off-by: Carlos Munoz <cmunoz@caviumnetworks.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/17388/
[jhogan@kernel.org: Add depends on SMP to fix
 "warning: symbol value '' invalid for MIPS_NR_CPU_NR_MAP"]
Signed-off-by: James Hogan <jhogan@kernel.org>

arch/mips/Kconfig

@@ -915,7 +915,8 @@ config CAVIUM_OCTEON_SOC
 	select USE_OF
 	select ARCH_SPARSEMEM_ENABLE
 	select SYS_SUPPORTS_SMP
-	select NR_CPUS_DEFAULT_16
+	select NR_CPUS_DEFAULT_64
+	select MIPS_NR_CPU_NR_MAP_1024
 	select BUILTIN_DTB
 	select MTD_COMPLEX_MAPPINGS
 	select SYS_SUPPORTS_RELOCATABLE
@@ -2725,6 +2726,15 @@ config NR_CPUS
 config MIPS_PERF_SHARED_TC_COUNTERS
 	bool
 
+config MIPS_NR_CPU_NR_MAP_1024
+	bool
+
+config MIPS_NR_CPU_NR_MAP
+	int
+	depends on SMP
+	default 1024 if MIPS_NR_CPU_NR_MAP_1024
+	default NR_CPUS if !MIPS_NR_CPU_NR_MAP_1024
+
 #
 # Timer Interrupt Frequency Configuration
 #

arch/mips/include/asm/smp.h

@@ -29,7 +29,7 @@ extern cpumask_t cpu_foreign_map[];
 
 /* Map from cpu id to sequential logical cpu number.  This will only
    not be idempotent when cpus failed to come on-line.	*/
-extern int __cpu_number_map[NR_CPUS];
+extern int __cpu_number_map[CONFIG_MIPS_NR_CPU_NR_MAP];
 #define cpu_number_map(cpu)  __cpu_number_map[cpu]
 
 /* The reverse map from sequential logical cpu number to cpu id.  */

arch/mips/kernel/smp.c

@@ -48,7 +48,7 @@
 #include <asm/setup.h>
 #include <asm/maar.h>
 
-int __cpu_number_map[NR_CPUS];		/* Map physical to logical */
+int __cpu_number_map[CONFIG_MIPS_NR_CPU_NR_MAP];   /* Map physical to logical */
 EXPORT_SYMBOL(__cpu_number_map);
 
 int __cpu_logical_map[NR_CPUS];		/* Map logical to physical */