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.pa...@wdc.com>
---
 arch/riscv/Kconfig          | 1 +
 arch/riscv/kernel/smpboot.c | 3 +++
 2 files changed, 4 insertions(+)

diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index eb56c82d8aa1..ac87a0ec8b5c 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -47,6 +47,7 @@ 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 HAVE_EBPF_JIT if 64BIT
 
diff --git a/arch/riscv/kernel/smpboot.c b/arch/riscv/kernel/smpboot.c
index 7a0b62252524..54f89d5b19ba 100644
--- a/arch/riscv/kernel/smpboot.c
+++ b/arch/riscv/kernel/smpboot.c
@@ -16,6 +16,7 @@
  * GNU General Public License for more details.
  */
 
+#include <linux/arch_topology.h>
 #include <linux/module.h>
 #include <linux/init.h>
 #include <linux/kernel.h>
@@ -43,6 +44,7 @@ static DECLARE_COMPLETION(cpu_running);
 
 void __init smp_prepare_boot_cpu(void)
 {
+       init_cpu_topology();
 }
 
 void __init smp_prepare_cpus(unsigned int max_cpus)
@@ -146,6 +148,7 @@ 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
-- 
2.21.0

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