[S390] cpu topology support for s390.

Add s390 backend so we can give the scheduler some hints about the
cpu topology.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>

1 files changed, 272 insertions, 0 deletions

diff --git a/arch/s390/kernel/topology.c b/arch/s390/kernel/topology.c
new file mode 100644
index 000000000000..369dc1c3bd10
--- /dev/null
+++ b/arch/s390/kernel/topology.c
@@ -0,0 +1,272 @@
+/*
+ *  arch/s390/kernel/topology.c
+ *
+ *    Copyright IBM Corp. 2007
+ *    Author(s): Heiko Carstens <heiko.carstens@de.ibm.com>
+ */
+
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/init.h>
+#include <linux/device.h>
+#include <linux/bootmem.h>
+#include <linux/sched.h>
+#include <linux/workqueue.h>
+#include <linux/cpu.h>
+#include <linux/smp.h>
+#include <asm/delay.h>
+#include <asm/s390_ext.h>
+#include <asm/sysinfo.h>
+
+#define CPU_BITS 64
+
+struct tl_cpu {
+        unsigned char reserved[6];
+        unsigned short origin;
+        unsigned long mask[CPU_BITS / BITS_PER_LONG];
+};
+
+struct tl_container {
+        unsigned char reserved[8];
+};
+
+union tl_entry {
+        unsigned char nl;
+        struct tl_cpu cpu;
+        struct tl_container container;
+};
+
+#define NR_MAG 6
+
+struct tl_info {
+        unsigned char reserved0[2];
+        unsigned short length;
+        unsigned char mag[NR_MAG];
+        unsigned char reserved1;
+        unsigned char mnest;
+        unsigned char reserved2[4];
+        union tl_entry tle[0];
+};
+
+struct core_info {
+        struct core_info *next;
+        cpumask_t mask;
+};
+
+static void topology_work_fn(struct work_struct *work);
+static struct tl_info *tl_info;
+static struct core_info core_info;
+static int machine_has_topology;
+static int machine_has_topology_irq;
+static struct timer_list topology_timer;
+static void set_topology_timer(void);
+static DECLARE_WORK(topology_work, topology_work_fn);
+
+cpumask_t cpu_coregroup_map(unsigned int cpu)
+{
+        struct core_info *core = &core_info;
+        cpumask_t mask;
+
+        cpus_clear(mask);
+        if (!machine_has_topology)
+                return cpu_present_map;
+        mutex_lock(&smp_cpu_state_mutex);
+        while (core) {
+                if (cpu_isset(cpu, core->mask)) {
+                        mask = core->mask;
+                        break;
+                }
+                core = core->next;
+        }
+        mutex_unlock(&smp_cpu_state_mutex);
+        if (cpus_empty(mask))
+                mask = cpumask_of_cpu(cpu);
+        return mask;
+}
+
+static void add_cpus_to_core(struct tl_cpu *tl_cpu, struct core_info *core)
+{
+        unsigned int cpu;
+
+        for (cpu = find_first_bit(&tl_cpu->mask[0], CPU_BITS);
+             cpu < CPU_BITS;
+             cpu = find_next_bit(&tl_cpu->mask[0], CPU_BITS, cpu + 1))
+        {
+                unsigned int rcpu, lcpu;
+
+                rcpu = CPU_BITS - 1 - cpu + tl_cpu->origin;
+                for_each_present_cpu(lcpu) {
+                        if (__cpu_logical_map[lcpu] == rcpu)
+                                cpu_set(lcpu, core->mask);
+                }
+        }
+}
+
+static void clear_cores(void)
+{
+        struct core_info *core = &core_info;
+
+        while (core) {
+                cpus_clear(core->mask);
+                core = core->next;
+        }
+}
+
+static union tl_entry *next_tle(union tl_entry *tle)
+{
+        if (tle->nl)
+                return (union tl_entry *)((struct tl_container *)tle + 1);
+        else
+                return (union tl_entry *)((struct tl_cpu *)tle + 1);
+}
+
+static void tl_to_cores(struct tl_info *info)
+{
+        union tl_entry *tle, *end;
+        struct core_info *core = &core_info;
+
+        mutex_lock(&smp_cpu_state_mutex);
+        clear_cores();
+        tle = (union tl_entry *)&info->tle;
+        end = (union tl_entry *)((unsigned long)info + info->length);
+        while (tle < end) {
+                switch (tle->nl) {
+                case 5:
+                case 4:
+                case 3:
+                case 2:
+                        break;
+                case 1:
+                        core = core->next;
+                        break;
+                case 0:
+                        add_cpus_to_core(&tle->cpu, core);
+                        break;
+                default:
+                        clear_cores();
+                        machine_has_topology = 0;
+                        return;
+                }
+                tle = next_tle(tle);
+        }
+        mutex_unlock(&smp_cpu_state_mutex);
+}
+
+static int ptf(void)
+{
+        int rc;
+
+        asm volatile(
+                "       .insn   rre,0xb9a20000,%1,%1\n"
+                "       ipm     %0\n"
+                "       srl     %0,28\n"
+                : "=d" (rc)
+                : "d" (2UL)  : "cc");
+        return rc;
+}
+
+void arch_update_cpu_topology(void)
+{
+        struct tl_info *info = tl_info;
+        struct sys_device *sysdev;
+        int cpu;
+
+        if (!machine_has_topology)
+                return;
+        ptf();
+        stsi(info, 15, 1, 2);
+        tl_to_cores(info);
+        for_each_online_cpu(cpu) {
+                sysdev = get_cpu_sysdev(cpu);
+                kobject_uevent(&sysdev->kobj, KOBJ_CHANGE);
+        }
+}
+
+static void topology_work_fn(struct work_struct *work)
+{
+        arch_reinit_sched_domains();
+}
+
+static void topology_timer_fn(unsigned long ignored)
+{
+        if (ptf())
+                schedule_work(&topology_work);
+        set_topology_timer();
+}
+
+static void set_topology_timer(void)
+{
+        topology_timer.function = topology_timer_fn;
+        topology_timer.data = 0;
+        topology_timer.expires = jiffies + 60 * HZ;
+        add_timer(&topology_timer);
+}
+
+static void topology_interrupt(__u16 code)
+{
+        schedule_work(&topology_work);
+}
+
+static int __init init_topology_update(void)
+{
+        int rc;
+
+        if (!machine_has_topology)
+                return 0;
+        init_timer(&topology_timer);
+        if (machine_has_topology_irq) {
+                rc = register_external_interrupt(0x2005, topology_interrupt);
+                if (rc)
+                        return rc;
+                ctl_set_bit(0, 8);
+        }
+        else
+                set_topology_timer();
+        return 0;
+}
+__initcall(init_topology_update);
+
+void __init s390_init_cpu_topology(void)
+{
+        unsigned long long facility_bits;
+        struct tl_info *info;
+        struct core_info *core;
+        int nr_cores;
+        int i;
+
+        if (stfle(&facility_bits, 1) <= 0)
+                return;
+        if (!(facility_bits & (1ULL << 52)) || !(facility_bits & (1ULL << 61)))
+                return;
+        machine_has_topology = 1;
+
+        if (facility_bits & (1ULL << 51))
+                machine_has_topology_irq = 1;
+
+        tl_info = alloc_bootmem_pages(PAGE_SIZE);
+        if (!tl_info)
+                goto error;
+        info = tl_info;
+        stsi(info, 15, 1, 2);
+
+        nr_cores = info->mag[NR_MAG - 2];
+        for (i = 0; i < info->mnest - 2; i++)
+                nr_cores *= info->mag[NR_MAG - 3 - i];
+
+        printk(KERN_INFO "CPU topology:");
+        for (i = 0; i < NR_MAG; i++)
+                printk(" %d", info->mag[i]);
+        printk(" / %d\n", info->mnest);
+
+        core = &core_info;
+        for (i = 0; i < nr_cores; i++) {
+                core->next = alloc_bootmem(sizeof(struct core_info));
+                core = core->next;
+                if (!core)
+                        goto error;
+        }
+        return;
+error:
+        machine_has_topology = 0;
+        machine_has_topology_irq = 0;
+}