RISC-V: Parse cpu topology during boot.

Currently, there are no topology defined for RISC-V.
Parse the cpu-map node from device tree and setup the
cpu topology.

CPU topology after applying the patch.
$cat /sys/devices/system/cpu/cpu2/topology/core_siblings_list
0-3
$cat /sys/devices/system/cpu/cpu3/topology/core_siblings_list
0-3
$cat /sys/devices/system/cpu/cpu3/topology/physical_package_id
0
$cat /sys/devices/system/cpu/cpu3/topology/core_id
3

Signed-off-by: Atish Patra <atish.patra@wdc.com>
Acked-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Paul Walmsley <paul.walmsley@sifive.com>

diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 59a4727..86ee362 100644 (file)
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -48,6 +48,7 @@ config RISCV
        select PCI_MSI if PCI
        select RISCV_TIMER
        select GENERIC_IRQ_MULTI_HANDLER
+       select GENERIC_ARCH_TOPOLOGY if SMP
        select ARCH_HAS_PTE_SPECIAL
        select ARCH_HAS_MMIOWB
        select HAVE_EBPF_JIT if 64BIT

diff --git a/arch/riscv/kernel/smpboot.c b/arch/riscv/kernel/smpboot.c
index 7462a44..18ae6da 100644 (file)
--- a/arch/riscv/kernel/smpboot.c
+++ b/arch/riscv/kernel/smpboot.c
@@ -8,6 +8,7 @@
  * Copyright (C) 2017 SiFive
  */
 
+#include <linux/arch_topology.h>
 #include <linux/module.h>
 #include <linux/init.h>
 #include <linux/kernel.h>
@@ -35,6 +36,7 @@ static DECLARE_COMPLETION(cpu_running);
 
 void __init smp_prepare_boot_cpu(void)
 {
+       init_cpu_topology();
 }
 
 void __init smp_prepare_cpus(unsigned int max_cpus)
@@ -138,6 +140,7 @@ asmlinkage void __init smp_callin(void)
 
        trap_init();
        notify_cpu_starting(smp_processor_id());
+       update_siblings_masks(smp_processor_id());
        set_cpu_online(smp_processor_id(), 1);
        /*
         * Remote TLB flushes are ignored while the CPU is offline, so emit