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Subject[RFT PATCH v1 4/4] RISC-V: Parse cpu topology during boot.
Date
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>
---
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 55da93f4..b0b1fe1a 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -42,6 +42,7 @@ config RISCV
select THREAD_INFO_IN_TASK
select RISCV_TIMER
select GENERIC_IRQ_MULTI_HANDLER
+ select GENERIC_ARCH_TOPOLOGY if SMP
select ARCH_HAS_PTE_SPECIAL

config MMU
diff --git a/arch/riscv/kernel/smpboot.c b/arch/riscv/kernel/smpboot.c
index 18cda0e8..5f435af7 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>
@@ -42,6 +43,7 @@ void *__cpu_up_task_pointer[NR_CPUS];

void __init smp_prepare_boot_cpu(void)
{
+ init_cpu_topology();
}

void __init smp_prepare_cpus(unsigned int max_cpus)
@@ -115,6 +117,7 @@ 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
--
2.7.4
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