xpc_partition.c

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/*
 * 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.
 *
 * Copyright (c) 2004-2008 Silicon Graphics, Inc.  All Rights Reserved.
 */

/*
 * Cross Partition Communication (XPC) partition support.
 *
 *  This is the part of XPC that detects the presence/absence of
 *  other partitions. It provides a heartbeat and monitors the
 *  heartbeats of other partitions.
 *
 */

#include <linux/device.h>
#include <linux/hardirq.h>
#include <linux/slab.h>
#include "xpc.h"
#include <asm/uv/uv_hub.h>

/* XPC is exiting flag */
int xpc_exiting;

/* this partition's reserved page pointers */
struct xpc_rsvd_page *xpc_rsvd_page;
static unsigned long *xpc_part_nasids;
unsigned long *xpc_mach_nasids;

static int xpc_nasid_mask_nbytes;   /* #of bytes in nasid mask */
int xpc_nasid_mask_nlongs;  /* #of longs in nasid mask */

struct xpc_partition *xpc_partitions;

/*
 * Guarantee that the kmalloc'd memory is cacheline aligned.
 */
void *
xpc_kmalloc_cacheline_aligned(size_t size, gfp_t flags, void **base)
{
    /* see if kmalloc will give us cachline aligned memory by default */
    *base = kmalloc(size, flags);
    if (*base == NULL)
        return NULL;

    if ((u64)*base == L1_CACHE_ALIGN((u64)*base))
        return *base;

    kfree(*base);

    /* nope, we'll have to do it ourselves */
    *base = kmalloc(size + L1_CACHE_BYTES, flags);
    if (*base == NULL)
        return NULL;

    return (void *)L1_CACHE_ALIGN((u64)*base);
}

/*
 * Given a nasid, get the physical address of the  partition's reserved page
 * for that nasid. This function returns 0 on any error.
 */
static unsigned long
xpc_get_rsvd_page_pa(int nasid)
{
    enum xp_retval ret;
    u64 cookie = 0;
    unsigned long rp_pa = nasid;    /* seed with nasid */
    size_t len = 0;
    size_t buf_len = 0;
    void *buf = buf;
    void *buf_base = NULL;
    enum xp_retval (*get_partition_rsvd_page_pa)
        (void *, u64 *, unsigned long *, size_t *) =
        xpc_arch_ops.get_partition_rsvd_page_pa;

    while (1) {

        /* !!! rp_pa will need to be _gpa on UV.
         * ??? So do we save it into the architecture specific parts
         * ??? of the xpc_partition structure? Do we rename this
         * ??? function or have two versions? Rename rp_pa for UV to
         * ??? rp_gpa?
         */
        ret = get_partition_rsvd_page_pa(buf, &cookie, &rp_pa, &len);

        dev_dbg(xpc_part, "SAL returned with ret=%d, cookie=0x%016lx, "
            "address=0x%016lx, len=0x%016lx\n", ret,
            (unsigned long)cookie, rp_pa, len);

        if (ret != xpNeedMoreInfo)
            break;

        /* !!! L1_CACHE_ALIGN() is only a sn2-bte_copy requirement */
        if (is_shub())
            len = L1_CACHE_ALIGN(len);

        if (len > buf_len) {
            if (buf_base != NULL)
                kfree(buf_base);
            buf_len = L1_CACHE_ALIGN(len);
            buf = xpc_kmalloc_cacheline_aligned(buf_len, GFP_KERNEL,
                                &buf_base);
            if (buf_base == NULL) {
                dev_err(xpc_part, "unable to kmalloc "
                    "len=0x%016lx\n", buf_len);
                ret = xpNoMemory;
                break;
            }
        }

        ret = xp_remote_memcpy(xp_pa(buf), rp_pa, len);
        if (ret != xpSuccess) {
            dev_dbg(xpc_part, "xp_remote_memcpy failed %d\n", ret);
            break;
        }
    }

    kfree(buf_base);

    if (ret != xpSuccess)
        rp_pa = 0;

    dev_dbg(xpc_part, "reserved page at phys address 0x%016lx\n", rp_pa);
    return rp_pa;
}

/*
 * Fill the partition reserved page with the information needed by
 * other partitions to discover we are alive and establish initial
 * communications.
 */
int
xpc_setup_rsvd_page(void)
{
    int ret;
    struct xpc_rsvd_page *rp;
    unsigned long rp_pa;
    unsigned long new_ts_jiffies;

    /* get the local reserved page's address */

    preempt_disable();
    rp_pa = xpc_get_rsvd_page_pa(xp_cpu_to_nasid(smp_processor_id()));
    preempt_enable();
    if (rp_pa == 0) {
        dev_err(xpc_part, "SAL failed to locate the reserved page\n");
        return -ESRCH;
    }
    rp = (struct xpc_rsvd_page *)__va(xp_socket_pa(rp_pa));

    if (rp->SAL_version < 3) {
        /* SAL_versions < 3 had a SAL_partid defined as a u8 */
        rp->SAL_partid &= 0xff;
    }
    BUG_ON(rp->SAL_partid != xp_partition_id);

    if (rp->SAL_partid < 0 || rp->SAL_partid >= xp_max_npartitions) {
        dev_err(xpc_part, "the reserved page's partid of %d is outside "
            "supported range (< 0 || >= %d)\n", rp->SAL_partid,
            xp_max_npartitions);
        return -EINVAL;
    }

    rp->version = XPC_RP_VERSION;
    rp->max_npartitions = xp_max_npartitions;

    /* establish the actual sizes of the nasid masks */
    if (rp->SAL_version == 1) {
        /* SAL_version 1 didn't set the nasids_size field */
        rp->SAL_nasids_size = 128;
    }
    xpc_nasid_mask_nbytes = rp->SAL_nasids_size;
    xpc_nasid_mask_nlongs = BITS_TO_LONGS(rp->SAL_nasids_size *
                          BITS_PER_BYTE);

    /* setup the pointers to the various items in the reserved page */
    xpc_part_nasids = XPC_RP_PART_NASIDS(rp);
    xpc_mach_nasids = XPC_RP_MACH_NASIDS(rp);

    ret = xpc_arch_ops.setup_rsvd_page(rp);
    if (ret != 0)
        return ret;

    /*
     * Set timestamp of when reserved page was setup by XPC.
     * This signifies to the remote partition that our reserved
     * page is initialized.
     */
    new_ts_jiffies = jiffies;
    if (new_ts_jiffies == 0 || new_ts_jiffies == rp->ts_jiffies)
        new_ts_jiffies++;
    rp->ts_jiffies = new_ts_jiffies;

    xpc_rsvd_page = rp;
    return 0;
}

void
xpc_teardown_rsvd_page(void)
{
    /* a zero timestamp indicates our rsvd page is not initialized */
    xpc_rsvd_page->ts_jiffies = 0;
}

/*
 * Get a copy of a portion of the remote partition's rsvd page.
 *
 * remote_rp points to a buffer that is cacheline aligned for BTE copies and
 * is large enough to contain a copy of their reserved page header and
 * part_nasids mask.
 */
enum xp_retval
xpc_get_remote_rp(int nasid, unsigned long *discovered_nasids,
          struct xpc_rsvd_page *remote_rp, unsigned long *remote_rp_pa)
{
    int l;
    enum xp_retval ret;

    /* get the reserved page's physical address */

    *remote_rp_pa = xpc_get_rsvd_page_pa(nasid);
    if (*remote_rp_pa == 0)
        return xpNoRsvdPageAddr;

    /* pull over the reserved page header and part_nasids mask */
    ret = xp_remote_memcpy(xp_pa(remote_rp), *remote_rp_pa,
                   XPC_RP_HEADER_SIZE + xpc_nasid_mask_nbytes);
    if (ret != xpSuccess)
        return ret;

    if (discovered_nasids != NULL) {
        unsigned long *remote_part_nasids =
            XPC_RP_PART_NASIDS(remote_rp);

        for (l = 0; l < xpc_nasid_mask_nlongs; l++)
            discovered_nasids[l] |= remote_part_nasids[l];
    }

    /* zero timestamp indicates the reserved page has not been setup */
    if (remote_rp->ts_jiffies == 0)
        return xpRsvdPageNotSet;

    if (XPC_VERSION_MAJOR(remote_rp->version) !=
        XPC_VERSION_MAJOR(XPC_RP_VERSION)) {
        return xpBadVersion;
    }

    /* check that both remote and local partids are valid for each side */
    if (remote_rp->SAL_partid < 0 ||
        remote_rp->SAL_partid >= xp_max_npartitions ||
        remote_rp->max_npartitions <= xp_partition_id) {
        return xpInvalidPartid;
    }

    if (remote_rp->SAL_partid == xp_partition_id)
        return xpLocalPartid;

    return xpSuccess;
}

/*
 * See if the other side has responded to a partition deactivate request
 * from us. Though we requested the remote partition to deactivate with regard
 * to us, we really only need to wait for the other side to disengage from us.
 */
int
xpc_partition_disengaged(struct xpc_partition *part)
{
    short partid = XPC_PARTID(part);
    int disengaged;

    disengaged = !xpc_arch_ops.partition_engaged(partid);
    if (part->disengage_timeout) {
        if (!disengaged) {
            if (time_is_after_jiffies(part->disengage_timeout)) {
                /* timelimit hasn't been reached yet */
                return 0;
            }

            /*
             * Other side hasn't responded to our deactivate
             * request in a timely fashion, so assume it's dead.
             */

            dev_info(xpc_part, "deactivate request to remote "
                 "partition %d timed out\n", partid);
            xpc_disengage_timedout = 1;
            xpc_arch_ops.assume_partition_disengaged(partid);
            disengaged = 1;
        }
        part->disengage_timeout = 0;

        /* cancel the timer function, provided it's not us */
        if (!in_interrupt())
            del_singleshot_timer_sync(&part->disengage_timer);

        DBUG_ON(part->act_state != XPC_P_AS_DEACTIVATING &&
            part->act_state != XPC_P_AS_INACTIVE);
        if (part->act_state != XPC_P_AS_INACTIVE)
            xpc_wakeup_channel_mgr(part);

        xpc_arch_ops.cancel_partition_deactivation_request(part);
    }
    return disengaged;
}

/*
 * Mark specified partition as active.
 */
enum xp_retval
xpc_mark_partition_active(struct xpc_partition *part)
{
    unsigned long irq_flags;
    enum xp_retval ret;

    dev_dbg(xpc_part, "setting partition %d to ACTIVE\n", XPC_PARTID(part));

    spin_lock_irqsave(&part->act_lock, irq_flags);
    if (part->act_state == XPC_P_AS_ACTIVATING) {
        part->act_state = XPC_P_AS_ACTIVE;
        ret = xpSuccess;
    } else {
        DBUG_ON(part->reason == xpSuccess);
        ret = part->reason;
    }
    spin_unlock_irqrestore(&part->act_lock, irq_flags);

    return ret;
}

/*
 * Start the process of deactivating the specified partition.
 */
void
xpc_deactivate_partition(const int line, struct xpc_partition *part,
             enum xp_retval reason)
{
    unsigned long irq_flags;

    spin_lock_irqsave(&part->act_lock, irq_flags);

    if (part->act_state == XPC_P_AS_INACTIVE) {
        XPC_SET_REASON(part, reason, line);
        spin_unlock_irqrestore(&part->act_lock, irq_flags);
        if (reason == xpReactivating) {
            /* we interrupt ourselves to reactivate partition */
            xpc_arch_ops.request_partition_reactivation(part);
        }
        return;
    }
    if (part->act_state == XPC_P_AS_DEACTIVATING) {
        if ((part->reason == xpUnloading && reason != xpUnloading) ||
            reason == xpReactivating) {
            XPC_SET_REASON(part, reason, line);
        }
        spin_unlock_irqrestore(&part->act_lock, irq_flags);
        return;
    }

    part->act_state = XPC_P_AS_DEACTIVATING;
    XPC_SET_REASON(part, reason, line);

    spin_unlock_irqrestore(&part->act_lock, irq_flags);

    /* ask remote partition to deactivate with regard to us */
    xpc_arch_ops.request_partition_deactivation(part);

    /* set a timelimit on the disengage phase of the deactivation request */
    part->disengage_timeout = jiffies + (xpc_disengage_timelimit * HZ);
    part->disengage_timer.expires = part->disengage_timeout;
    add_timer(&part->disengage_timer);

    dev_dbg(xpc_part, "bringing partition %d down, reason = %d\n",
        XPC_PARTID(part), reason);

    xpc_partition_going_down(part, reason);
}

/*
 * Mark specified partition as inactive.
 */
void
xpc_mark_partition_inactive(struct xpc_partition *part)
{
    unsigned long irq_flags;

    dev_dbg(xpc_part, "setting partition %d to INACTIVE\n",
        XPC_PARTID(part));

    spin_lock_irqsave(&part->act_lock, irq_flags);
    part->act_state = XPC_P_AS_INACTIVE;
    spin_unlock_irqrestore(&part->act_lock, irq_flags);
    part->remote_rp_pa = 0;
}

/*
 * SAL has provided a partition and machine mask.  The partition mask
 * contains a bit for each even nasid in our partition.  The machine
 * mask contains a bit for each even nasid in the entire machine.
 *
 * Using those two bit arrays, we can determine which nasids are
 * known in the machine.  Each should also have a reserved page
 * initialized if they are available for partitioning.
 */
void
xpc_discovery(void)
{
    void *remote_rp_base;
    struct xpc_rsvd_page *remote_rp;
    unsigned long remote_rp_pa;
    int region;
    int region_size;
    int max_regions;
    int nasid;
    struct xpc_rsvd_page *rp;
    unsigned long *discovered_nasids;
    enum xp_retval ret;

    remote_rp = xpc_kmalloc_cacheline_aligned(XPC_RP_HEADER_SIZE +
                          xpc_nasid_mask_nbytes,
                          GFP_KERNEL, &remote_rp_base);
    if (remote_rp == NULL)
        return;

    discovered_nasids = kzalloc(sizeof(long) * xpc_nasid_mask_nlongs,
                    GFP_KERNEL);
    if (discovered_nasids == NULL) {
        kfree(remote_rp_base);
        return;
    }

    rp = (struct xpc_rsvd_page *)xpc_rsvd_page;

    /*
     * The term 'region' in this context refers to the minimum number of
     * nodes that can comprise an access protection grouping. The access
     * protection is in regards to memory, IOI and IPI.
     */
    region_size = xp_region_size;

    if (is_uv())
        max_regions = 256;
    else {
        max_regions = 64;

        switch (region_size) {
        case 128:
            max_regions *= 2;
        case 64:
            max_regions *= 2;
        case 32:
            max_regions *= 2;
            region_size = 16;
            DBUG_ON(!is_shub2());
        }
    }

    for (region = 0; region < max_regions; region++) {

        if (xpc_exiting)
            break;

        dev_dbg(xpc_part, "searching region %d\n", region);

        for (nasid = (region * region_size * 2);
             nasid < ((region + 1) * region_size * 2); nasid += 2) {

            if (xpc_exiting)
                break;

            dev_dbg(xpc_part, "checking nasid %d\n", nasid);

            if (test_bit(nasid / 2, xpc_part_nasids)) {
                dev_dbg(xpc_part, "PROM indicates Nasid %d is "
                    "part of the local partition; skipping "
                    "region\n", nasid);
                break;
            }

            if (!(test_bit(nasid / 2, xpc_mach_nasids))) {
                dev_dbg(xpc_part, "PROM indicates Nasid %d was "
                    "not on Numa-Link network at reset\n",
                    nasid);
                continue;
            }

            if (test_bit(nasid / 2, discovered_nasids)) {
                dev_dbg(xpc_part, "Nasid %d is part of a "
                    "partition which was previously "
                    "discovered\n", nasid);
                continue;
            }

            /* pull over the rsvd page header & part_nasids mask */

            ret = xpc_get_remote_rp(nasid, discovered_nasids,
                        remote_rp, &remote_rp_pa);
            if (ret != xpSuccess) {
                dev_dbg(xpc_part, "unable to get reserved page "
                    "from nasid %d, reason=%d\n", nasid,
                    ret);

                if (ret == xpLocalPartid)
                    break;

                continue;
            }

            xpc_arch_ops.request_partition_activation(remote_rp,
                             remote_rp_pa, nasid);
        }
    }

    kfree(discovered_nasids);
    kfree(remote_rp_base);
}

/*
 * Given a partid, get the nasids owned by that partition from the
 * remote partition's reserved page.
 */
enum xp_retval
xpc_initiate_partid_to_nasids(short partid, void *nasid_mask)
{
    struct xpc_partition *part;
    unsigned long part_nasid_pa;

    part = &xpc_partitions[partid];
    if (part->remote_rp_pa == 0)
        return xpPartitionDown;

    memset(nasid_mask, 0, xpc_nasid_mask_nbytes);

    part_nasid_pa = (unsigned long)XPC_RP_PART_NASIDS(part->remote_rp_pa);

    return xp_remote_memcpy(xp_pa(nasid_mask), part_nasid_pa,
                xpc_nasid_mask_nbytes);
}