From f9f130ff2ec93c5949576bbfb168cc9530c23649 Mon Sep 17 00:00:00 2001

From: Srikar Dronamraju <srikar@linux.vnet.ibm.com>

Date: Mon, 10 Aug 2020 12:48:31 +0530

Subject: [PATCH] powerpc/numa: Detect support for coregroup

References: bsc#1209999 ltc#202140 bsc#1142685 ltc#179509 FATE#327775 git-fixes

Patch-mainline: v5.10-rc1

Git-commit: f9f130ff2ec93c5949576bbfb168cc9530c23649

Add support for grouping cores based on the device-tree classification.

- The last domain in the associativity domains always refers to the

core.

- If primary reference domain happens to be the penultimate domain in

the associativity domains device-tree property, then there are no

coregroups. However if its not a penultimate domain, then there are

coregroups. There can be more than one coregroup. For now we would be

interested in the last or the smallest coregroups, i.e one sub-group

per DIE.

Currently there are no firmwares that are exposing this grouping. Hence

allow the basis for grouping to be abstract.  Once the firmware starts

using this grouping, code would be added to detect the type of grouping

and adjust the sd domain flags accordingly.

Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>

Reviewed-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Link: https://lore.kernel.org/r/20200810071834.92514-8-srikar@linux.vnet.ibm.com

Acked-by: Michal Suchanek <msuchanek@suse.de>

---

 arch/powerpc/include/asm/smp.h |  1 +

 arch/powerpc/kernel/smp.c      |  1 +

 arch/powerpc/mm/numa.c         | 34 +++++++++++++++++++++-------------

 3 files changed, 23 insertions(+), 13 deletions(-)

diff --git a/arch/powerpc/include/asm/smp.h b/arch/powerpc/include/asm/smp.h

index b727f5f7b8f9..041f0b97c45b 100644

--- a/arch/powerpc/include/asm/smp.h

+++ b/arch/powerpc/include/asm/smp.h

@@ -28,6 +28,7 @@

 extern int boot_cpuid;

 extern int spinning_secondaries;

 extern u32 *cpu_to_phys_id;

+extern bool coregroup_enabled;

 extern void cpu_die(void);

 extern int cpu_to_chip_id(int cpu);

diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c

--- a/arch/powerpc/kernel/smp.c

+++ b/arch/powerpc/kernel/smp.c

@@ -75,6 +75,7 @@ static DEFINE_PER_CPU(int, cpu_state) = { 0 };

 struct thread_info *secondary_ti;

 bool has_big_cores;

+bool coregroup_enabled;

 DEFINE_PER_CPU(cpumask_var_t, cpu_sibling_map);

 DEFINE_PER_CPU(cpumask_var_t, cpu_smallcore_map);

diff --git a/arch/powerpc/mm/numa.c b/arch/powerpc/mm/numa.c

index 481951ac3e55..b2c44c5a81fb 100644

--- a/arch/powerpc/mm/numa.c

+++ b/arch/powerpc/mm/numa.c

@@ -897,7 +897,9 @@ static void __init setup_node_data(int nid, u64 start_pfn, u64 end_pfn)

 static void __init find_possible_nodes(void)

 {

 	struct device_node *rtas;

-	u32 numnodes, i;

+	const __be32 *domains;

+	int prop_length, max_nodes;

+	u32 i;

 	if (!numa_enabled)

 		return;

@@ -906,25 +908,31 @@ static void __init find_possible_nodes(void)

 	if (!rtas)

 		return;

-	if (of_property_read_u32_index(rtas, "ibm,current-associativity-domains",

-				min_common_depth, &numnodes)) {

-		/*

-		 * ibm,current-associativity-domains is a fairly recent

-		 * property. If it doesn't exist, then fallback on

-		 * ibm,max-associativity-domains. Current denotes what the

-		 * platform can support compared to max which denotes what the

-		 * Hypervisor can support.

-		 */

-		if (of_property_read_u32_index(rtas, "ibm,max-associativity-domains",

-				min_common_depth, &numnodes))

+	/*

+	 * ibm,current-associativity-domains is a fairly recent property. If

+	 * it doesn't exist, then fallback on ibm,max-associativity-domains.

+	 * Current denotes what the platform can support compared to max

+	 * which denotes what the Hypervisor can support.

+	 */

+	domains = of_get_property(rtas, "ibm,current-associativity-domains",

+					&prop_length);

+	if (!domains) {

+		domains = of_get_property(rtas, "ibm,max-associativity-domains",

+					&prop_length);

+		if (!domains)

 			goto out;

 	}

-	for (i = 0; i < numnodes; i++) {

+	max_nodes = of_read_number(&domains[min_common_depth], 1);

+	for (i = 0; i < max_nodes; i++) {

 		if (!node_possible(i))

 			node_set(i, node_possible_map);

 	}

+	prop_length /= sizeof(int);

+	if (prop_length > min_common_depth + 2)

+		coregroup_enabled = 1;

+

 out:

 	of_node_put(rtas);

 }

-- 

2.40.0