parisc: Add CPU topology support

Add topology support, including multi-core scheduler support on
PA8800/PA8900 CPUs and enhanced output in /proc/cpuinfo, e.g.
lscpu now reports on a single-socket, dual-core machine:

Architecture:          parisc64
CPU(s):                2
On-line CPU(s) list:   0,1
Thread(s) per core:    1
Core(s) per socket:    2
Socket(s):             1
CPU family:            PA-RISC 2.0
Model name:            PA8800 (Mako)

Signed-off-by: Helge Deller <deller@gmx.de>

diff --git a/arch/parisc/Kconfig b/arch/parisc/Kconfig
index 1fd3eb5b66c6c6586c028b9002dcb185f6d54e56..7171c21bb0af324927436acd6b55a6a0815a11d5 100644 (file)
--- a/arch/parisc/Kconfig
+++ b/arch/parisc/Kconfig
@@ -32,6 +32,7 @@ config PARISC
        select GENERIC_PCI_IOMAP
        select ARCH_HAVE_NMI_SAFE_CMPXCHG
        select GENERIC_SMP_IDLE_THREAD
+       select GENERIC_CPU_DEVICES
        select GENERIC_STRNCPY_FROM_USER
        select SYSCTL_ARCH_UNALIGN_ALLOW
        select SYSCTL_EXCEPTION_TRACE
@@ -288,6 +289,21 @@ config SMP
 
          If you don't know what to do here, say N.
 
+config PARISC_CPU_TOPOLOGY
+       bool "Support cpu topology definition"
+       depends on SMP
+       default y
+       help
+         Support PARISC cpu topology definition.
+
+config SCHED_MC
+       bool "Multi-core scheduler support"
+       depends on PARISC_CPU_TOPOLOGY && PA8X00
+       help
+         Multi-core scheduler support improves the CPU scheduler's decision
+         making when dealing with multi-core CPU chips at a cost of slightly
+         increased overhead in some places. If unsure say N here.
+
 config IRQSTACKS
        bool "Use separate kernel stacks when processing interrupts"
        default y

diff --git a/arch/parisc/include/asm/topology.h b/arch/parisc/include/asm/topology.h
new file mode 100644 (file)
index 0000000..6f0750c
--- /dev/null
+++ b/arch/parisc/include/asm/topology.h
@@ -0,0 +1,36 @@
+#ifndef _ASM_PARISC_TOPOLOGY_H
+#define _ASM_PARISC_TOPOLOGY_H
+
+#ifdef CONFIG_PARISC_CPU_TOPOLOGY
+
+#include <linux/cpumask.h>
+
+struct cputopo_parisc {
+       int thread_id;
+       int core_id;
+       int socket_id;
+       cpumask_t thread_sibling;
+       cpumask_t core_sibling;
+};
+
+extern struct cputopo_parisc cpu_topology[NR_CPUS];
+
+#define topology_physical_package_id(cpu)      (cpu_topology[cpu].socket_id)
+#define topology_core_id(cpu)          (cpu_topology[cpu].core_id)
+#define topology_core_cpumask(cpu)     (&cpu_topology[cpu].core_sibling)
+#define topology_sibling_cpumask(cpu)  (&cpu_topology[cpu].thread_sibling)
+
+void init_cpu_topology(void);
+void store_cpu_topology(unsigned int cpuid);
+const struct cpumask *cpu_coregroup_mask(int cpu);
+
+#else
+
+static inline void init_cpu_topology(void) { }
+static inline void store_cpu_topology(unsigned int cpuid) { }
+
+#endif
+
+#include <asm-generic/topology.h>
+
+#endif /* _ASM_ARM_TOPOLOGY_H */

diff --git a/arch/parisc/kernel/Makefile b/arch/parisc/kernel/Makefile
index 649dc3eda4488205346c19912b9dc2baae4b2863..eafd06ab59ef8db3b21aabccc5021a05877e38f7 100644 (file)
--- a/arch/parisc/kernel/Makefile
+++ b/arch/parisc/kernel/Makefile
@@ -9,8 +9,7 @@ obj-y           := cache.o pacache.o setup.o pdt.o traps.o time.o irq.o \
                   pa7300lc.o syscall.o entry.o sys_parisc.o firmware.o \
                   ptrace.o hardware.o inventory.o drivers.o \
                   signal.o hpmc.o real2.o parisc_ksyms.o unaligned.o \
-                  process.o processor.o pdc_cons.o pdc_chassis.o unwind.o \
-                  topology.o
+                  process.o processor.o pdc_cons.o pdc_chassis.o unwind.o
 
 ifdef CONFIG_FUNCTION_TRACER
 # Do not profile debug and lowlevel utilities
@@ -30,5 +29,6 @@ obj-$(CONFIG_AUDIT)   += audit.o
 obj64-$(CONFIG_AUDIT)  += compat_audit.o
 # only supported for PCX-W/U in 64-bit mode at the moment
 obj-$(CONFIG_64BIT)    += perf.o perf_asm.o $(obj64-y)
+obj-$(CONFIG_PARISC_CPU_TOPOLOGY)      += topology.o
 obj-$(CONFIG_FUNCTION_TRACER)          += ftrace.o
 obj-$(CONFIG_FUNCTION_GRAPH_TRACER)    += ftrace.o

diff --git a/arch/parisc/kernel/processor.c b/arch/parisc/kernel/processor.c
index e120d63c1b285ad545c2281de0abbbcc2dde6e08..45cc65902fcebb88edc6f98d96241d4a1dbf7617 100644 (file)
--- a/arch/parisc/kernel/processor.c
+++ b/arch/parisc/kernel/processor.c
@@ -184,6 +184,9 @@ static int __init processor_probe(struct parisc_device *dev)
        p->txn_addr = txn_addr; /* save CPU IRQ address */
        p->cpu_num = cpu_info.cpu_num;
        p->cpu_loc = cpu_info.cpu_loc;
+
+       store_cpu_topology(cpuid);
+
 #ifdef CONFIG_SMP
        /*
        ** FIXME: review if any other initialization is clobbered
@@ -325,6 +328,8 @@ int __init init_per_cpu(int cpunum)
        set_firmware_width();
        ret = pdc_coproc_cfg(&coproc_cfg);
 
+       store_cpu_topology(cpunum);
+
        if(ret >= 0 && coproc_cfg.ccr_functional) {
                mtctl(coproc_cfg.ccr_functional, 10);  /* 10 == Coprocessor Control Reg */
 
@@ -388,6 +393,14 @@ show_cpuinfo (struct seq_file *m, void *v)
                                 boot_cpu_data.cpu_hz / 1000000,
                                 boot_cpu_data.cpu_hz % 1000000  );
 
+#ifdef CONFIG_PARISC_CPU_TOPOLOGY
+               seq_printf(m, "physical id\t: %d\n",
+                               topology_physical_package_id(cpu));
+               seq_printf(m, "siblings\t: %d\n",
+                               cpumask_weight(topology_core_cpumask(cpu)));
+               seq_printf(m, "core id\t\t: %d\n", topology_core_id(cpu));
+#endif
+
                seq_printf(m, "capabilities\t:");
                if (boot_cpu_data.pdc.capabilities & PDC_MODEL_OS32)
                        seq_puts(m, " os32");

diff --git a/arch/parisc/kernel/setup.c b/arch/parisc/kernel/setup.c
index f7d0c3b33d70a53b5350729f1e3d59b2e803749b..0e9675f857a5ca910769b8de1335cd318d0e2c9d 100644 (file)
--- a/arch/parisc/kernel/setup.c
+++ b/arch/parisc/kernel/setup.c
@@ -408,6 +408,8 @@ void __init start_parisc(void)
 
        cpunum = smp_processor_id();
 
+       init_cpu_topology();
+
        set_firmware_width_unlocked();
 
        ret = pdc_coproc_cfg_unlocked(&coproc_cfg);

diff --git a/arch/parisc/kernel/topology.c b/arch/parisc/kernel/topology.c
index f5159381fdd6f04be4679a0dd66ab474bb78f490..0a10e4ddc528f76f40364a3e3b49ece350d91519 100644 (file)
--- a/arch/parisc/kernel/topology.c
+++ b/arch/parisc/kernel/topology.c
@@ -1,37 +1,142 @@
 /*
- * arch/parisc/kernel/topology.c - Populate sysfs with topology information
+ * arch/parisc/kernel/topology.c
  *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
+ * Copyright (C) 2017 Helge Deller <deller@gmx.de>
  *
- * This program is distributed in the hope that it will be useful, but
- * WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
- * NON INFRINGEMENT.  See the GNU General Public License for more
- * details.
+ * based on arch/arm/kernel/topology.c
  *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
  */
 
-#include <linux/init.h>
-#include <linux/smp.h>
-#include <linux/cpu.h>
-#include <linux/cache.h>
+#include <linux/percpu.h>
+#include <linux/sched.h>
+#include <linux/sched/topology.h>
 
-static DEFINE_PER_CPU(struct cpu, cpu_devices);
+#include <asm/topology.h>
 
-static int __init topology_init(void)
+ /*
+  * cpu topology table
+  */
+struct cputopo_parisc cpu_topology[NR_CPUS] __read_mostly;
+EXPORT_SYMBOL_GPL(cpu_topology);
+
+const struct cpumask *cpu_coregroup_mask(int cpu)
 {
-       int num;
+       return &cpu_topology[cpu].core_sibling;
+}
+
+static void update_siblings_masks(unsigned int cpuid)
+{
+       struct cputopo_parisc *cpu_topo, *cpuid_topo = &cpu_topology[cpuid];
+       int cpu;
+
+       /* update core and thread sibling masks */
+       for_each_possible_cpu(cpu) {
+               cpu_topo = &cpu_topology[cpu];
+
+               if (cpuid_topo->socket_id != cpu_topo->socket_id)
+                       continue;
+
+               cpumask_set_cpu(cpuid, &cpu_topo->core_sibling);
+               if (cpu != cpuid)
+                       cpumask_set_cpu(cpu, &cpuid_topo->core_sibling);
+
+               if (cpuid_topo->core_id != cpu_topo->core_id)
+                       continue;
+
+               cpumask_set_cpu(cpuid, &cpu_topo->thread_sibling);
+               if (cpu != cpuid)
+                       cpumask_set_cpu(cpu, &cpuid_topo->thread_sibling);
+       }
+       smp_wmb();
+}
+
+static int dualcores_found __initdata;
+
+/*
+ * store_cpu_topology is called at boot when only one cpu is running
+ * and with the mutex cpu_hotplug.lock locked, when several cpus have booted,
+ * which prevents simultaneous write access to cpu_topology array
+ */
+void __init store_cpu_topology(unsigned int cpuid)
+{
+       struct cputopo_parisc *cpuid_topo = &cpu_topology[cpuid];
+       struct cpuinfo_parisc *p;
+       int max_socket = -1;
+       unsigned long cpu;
+
+       /* If the cpu topology has been already set, just return */
+       if (cpuid_topo->core_id != -1)
+               return;
 
-       for_each_present_cpu(num) {
-               register_cpu(&per_cpu(cpu_devices, num), num);
+       /* create cpu topology mapping */
+       cpuid_topo->thread_id = -1;
+       cpuid_topo->core_id = 0;
+
+       p = &per_cpu(cpu_data, cpuid);
+       for_each_online_cpu(cpu) {
+               const struct cpuinfo_parisc *cpuinfo = &per_cpu(cpu_data, cpu);
+
+               if (cpu == cpuid) /* ignore current cpu */
+                       continue;
+
+               if (cpuinfo->cpu_loc == p->cpu_loc) {
+                       cpuid_topo->core_id = cpu_topology[cpu].core_id;
+                       if (p->cpu_loc) {
+                               cpuid_topo->core_id++;
+                               cpuid_topo->socket_id = cpu_topology[cpu].socket_id;
+                               dualcores_found = 1;
+                               continue;
+                       }
+               }
+
+               if (cpuid_topo->socket_id == -1)
+                       max_socket = max(max_socket, cpu_topology[cpu].socket_id);
        }
-       return 0;
+
+       if (cpuid_topo->socket_id == -1)
+               cpuid_topo->socket_id = max_socket + 1;
+
+       update_siblings_masks(cpuid);
+
+       pr_info("CPU%u: thread %d, cpu %d, socket %d\n",
+               cpuid, cpu_topology[cpuid].thread_id,
+               cpu_topology[cpuid].core_id,
+               cpu_topology[cpuid].socket_id);
 }
 
-subsys_initcall(topology_init);
+static struct sched_domain_topology_level parisc_mc_topology[] = {
+#ifdef CONFIG_SCHED_MC
+       { cpu_coregroup_mask, cpu_core_flags, SD_INIT_NAME(MC) },
+#endif
+
+       { cpu_cpu_mask, SD_INIT_NAME(DIE) },
+       { NULL, },
+};
+
+/*
+ * init_cpu_topology is called at boot when only one cpu is running
+ * which prevent simultaneous write access to cpu_topology array
+ */
+void __init init_cpu_topology(void)
+{
+       unsigned int cpu;
+
+       /* init core mask and capacity */
+       for_each_possible_cpu(cpu) {
+               struct cputopo_parisc *cpu_topo = &(cpu_topology[cpu]);
+
+               cpu_topo->thread_id = -1;
+               cpu_topo->core_id =  -1;
+               cpu_topo->socket_id = -1;
+               cpumask_clear(&cpu_topo->core_sibling);
+               cpumask_clear(&cpu_topo->thread_sibling);
+       }
+       smp_wmb();
+
+       /* Set scheduler topology descriptor */
+       if (dualcores_found)
+               set_sched_topology(parisc_mc_topology);
+}