MIPS: MT: core_nvpes function to retrieve VPE count

This function simply returns the number of VPEs present in the current
core, or 1 if the core does not implement the MT ASE. In SMP kernels
this will typically equal smp_num_siblings, however it will also be
usable in UP kernels and helps prepare for the possibility of a
heterogenous system where the VPE count is not the same across all
cores.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6665/Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/include/asm/mipsmtregs.h

@@ -176,6 +176,17 @@
 
 #ifndef __ASSEMBLY__
 
+static inline unsigned core_nvpes(void)
+{
+	unsigned conf0;
+
+	if (!cpu_has_mipsmt)
+		return 1;
+
+	conf0 = read_c0_mvpconf0();
+	return ((conf0 & MVPCONF0_PVPE) >> MVPCONF0_PVPE_SHIFT) + 1;
+}
+
 static inline unsigned int dvpe(void)
 {
 	int res = 0;