x86/UV2: Work around BAU bug
[pandora-kernel.git] / arch / x86 / platform / uv / tlb_uv.c
index c425ff1..9010ca7 100644 (file)
@@ -157,13 +157,14 @@ static int __init uvhub_to_first_apicid(int uvhub)
  * clear of the Timeout bit (as well) will free the resource. No reply will
  * be sent (the hardware will only do one reply per message).
  */
-static void reply_to_message(struct msg_desc *mdp, struct bau_control *bcp)
+static void reply_to_message(struct msg_desc *mdp, struct bau_control *bcp,
+                                               int do_acknowledge)
 {
        unsigned long dw;
        struct bau_pq_entry *msg;
 
        msg = mdp->msg;
-       if (!msg->canceled) {
+       if (!msg->canceled && do_acknowledge) {
                dw = (msg->swack_vec << UV_SW_ACK_NPENDING) | msg->swack_vec;
                write_mmr_sw_ack(dw);
        }
@@ -212,8 +213,8 @@ static void bau_process_retry_msg(struct msg_desc *mdp,
                        if (mmr & (msg_res << UV_SW_ACK_NPENDING)) {
                                unsigned long mr;
                                /*
-                                * is the resource timed out?
-                                * make everyone ignore the cancelled message.
+                                * Is the resource timed out?
+                                * Make everyone ignore the cancelled message.
                                 */
                                msg2->canceled = 1;
                                stat->d_canceled++;
@@ -231,8 +232,8 @@ static void bau_process_retry_msg(struct msg_desc *mdp,
  * Do all the things a cpu should do for a TLB shootdown message.
  * Other cpu's may come here at the same time for this message.
  */
-static void bau_process_message(struct msg_desc *mdp,
-                                       struct bau_control *bcp)
+static void bau_process_message(struct msg_desc *mdp, struct bau_control *bcp,
+                                               int do_acknowledge)
 {
        short socket_ack_count = 0;
        short *sp;
@@ -284,8 +285,9 @@ static void bau_process_message(struct msg_desc *mdp,
                if (msg_ack_count == bcp->cpus_in_uvhub) {
                        /*
                         * All cpus in uvhub saw it; reply
+                        * (unless we are in the UV2 workaround)
                         */
-                       reply_to_message(mdp, bcp);
+                       reply_to_message(mdp, bcp, do_acknowledge);
                }
        }
 
@@ -491,27 +493,138 @@ static int uv1_wait_completion(struct bau_desc *bau_desc,
 /*
  * UV2 has an extra bit of status in the ACTIVATION_STATUS_2 register.
  */
-static unsigned long uv2_read_status(unsigned long offset, int rshft, int cpu)
+static unsigned long uv2_read_status(unsigned long offset, int rshft, int desc)
 {
        unsigned long descriptor_status;
        unsigned long descriptor_status2;
 
        descriptor_status = ((read_lmmr(offset) >> rshft) & UV_ACT_STATUS_MASK);
-       descriptor_status2 = (read_mmr_uv2_status() >> cpu) & 0x1UL;
+       descriptor_status2 = (read_mmr_uv2_status() >> desc) & 0x1UL;
        descriptor_status = (descriptor_status << 1) | descriptor_status2;
        return descriptor_status;
 }
 
+/*
+ * Return whether the status of the descriptor that is normally used for this
+ * cpu (the one indexed by its hub-relative cpu number) is busy.
+ * The status of the original 32 descriptors is always reflected in the 64
+ * bits of UVH_LB_BAU_SB_ACTIVATION_STATUS_0.
+ * The bit provided by the activation_status_2 register is irrelevant to
+ * the status if it is only being tested for busy or not busy.
+ */
+int normal_busy(struct bau_control *bcp)
+{
+       int cpu = bcp->uvhub_cpu;
+       int mmr_offset;
+       int right_shift;
+
+       mmr_offset = UVH_LB_BAU_SB_ACTIVATION_STATUS_0;
+       right_shift = cpu * UV_ACT_STATUS_SIZE;
+       return (((((read_lmmr(mmr_offset) >> right_shift) &
+                               UV_ACT_STATUS_MASK)) << 1) == UV2H_DESC_BUSY);
+}
+
+/*
+ * Entered when a bau descriptor has gone into a permanent busy wait because
+ * of a hardware bug.
+ * Workaround the bug.
+ */
+int handle_uv2_busy(struct bau_control *bcp)
+{
+       int busy_one = bcp->using_desc;
+       int normal = bcp->uvhub_cpu;
+       int selected = -1;
+       int i;
+       unsigned long descriptor_status;
+       unsigned long status;
+       int mmr_offset;
+       struct bau_desc *bau_desc_old;
+       struct bau_desc *bau_desc_new;
+       struct bau_control *hmaster = bcp->uvhub_master;
+       struct ptc_stats *stat = bcp->statp;
+       cycles_t ttm;
+
+       stat->s_uv2_wars++;
+       spin_lock(&hmaster->uvhub_lock);
+       /* try for the original first */
+       if (busy_one != normal) {
+               if (!normal_busy(bcp))
+                       selected = normal;
+       }
+       if (selected < 0) {
+               /* can't use the normal, select an alternate */
+               mmr_offset = UVH_LB_BAU_SB_ACTIVATION_STATUS_1;
+               descriptor_status = read_lmmr(mmr_offset);
+
+               /* scan available descriptors 32-63 */
+               for (i = 0; i < UV_CPUS_PER_AS; i++) {
+                       if ((hmaster->inuse_map & (1 << i)) == 0) {
+                               status = ((descriptor_status >>
+                                               (i * UV_ACT_STATUS_SIZE)) &
+                                               UV_ACT_STATUS_MASK) << 1;
+                               if (status != UV2H_DESC_BUSY) {
+                                       selected = i + UV_CPUS_PER_AS;
+                                       break;
+                               }
+                       }
+               }
+       }
+
+       if (busy_one != normal)
+               /* mark the busy alternate as not in-use */
+               hmaster->inuse_map &= ~(1 << (busy_one - UV_CPUS_PER_AS));
+
+       if (selected >= 0) {
+               /* switch to the selected descriptor */
+               if (selected != normal) {
+                       /* set the selected alternate as in-use */
+                       hmaster->inuse_map |=
+                                       (1 << (selected - UV_CPUS_PER_AS));
+                       if (selected > stat->s_uv2_wars_hw)
+                               stat->s_uv2_wars_hw = selected;
+               }
+               bau_desc_old = bcp->descriptor_base;
+               bau_desc_old += (ITEMS_PER_DESC * busy_one);
+               bcp->using_desc = selected;
+               bau_desc_new = bcp->descriptor_base;
+               bau_desc_new += (ITEMS_PER_DESC * selected);
+               *bau_desc_new = *bau_desc_old;
+       } else {
+               /*
+                * All are busy. Wait for the normal one for this cpu to
+                * free up.
+                */
+               stat->s_uv2_war_waits++;
+               spin_unlock(&hmaster->uvhub_lock);
+               ttm = get_cycles();
+               do {
+                       cpu_relax();
+               } while (normal_busy(bcp));
+               spin_lock(&hmaster->uvhub_lock);
+               /* switch to the original descriptor */
+               bcp->using_desc = normal;
+               bau_desc_old = bcp->descriptor_base;
+               bau_desc_old += (ITEMS_PER_DESC * bcp->using_desc);
+               bcp->using_desc = (ITEMS_PER_DESC * normal);
+               bau_desc_new = bcp->descriptor_base;
+               bau_desc_new += (ITEMS_PER_DESC * normal);
+               *bau_desc_new = *bau_desc_old; /* copy the entire descriptor */
+       }
+       spin_unlock(&hmaster->uvhub_lock);
+       return FLUSH_RETRY_BUSYBUG;
+}
+
 static int uv2_wait_completion(struct bau_desc *bau_desc,
                                unsigned long mmr_offset, int right_shift,
                                struct bau_control *bcp, long try)
 {
        unsigned long descriptor_stat;
        cycles_t ttm;
-       int cpu = bcp->uvhub_cpu;
+       int desc = bcp->using_desc;
+       long busy_reps = 0;
        struct ptc_stats *stat = bcp->statp;
 
-       descriptor_stat = uv2_read_status(mmr_offset, right_shift, cpu);
+       descriptor_stat = uv2_read_status(mmr_offset, right_shift, desc);
 
        /* spin on the status MMR, waiting for it to go idle */
        while (descriptor_stat != UV2H_DESC_IDLE) {
@@ -542,12 +655,23 @@ static int uv2_wait_completion(struct bau_desc *bau_desc,
                        bcp->conseccompletes = 0;
                        return FLUSH_RETRY_TIMEOUT;
                } else {
+                       busy_reps++;
+                       if (busy_reps > 1000000) {
+                               /* not to hammer on the clock */
+                               busy_reps = 0;
+                               ttm = get_cycles();
+                               if ((ttm - bcp->send_message) >
+                                       (bcp->clocks_per_100_usec)) {
+                                       return handle_uv2_busy(bcp);
+                               }
+                       }
                        /*
                         * descriptor_stat is still BUSY
                         */
                        cpu_relax();
                }
-               descriptor_stat = uv2_read_status(mmr_offset, right_shift, cpu);
+               descriptor_stat = uv2_read_status(mmr_offset, right_shift,
+                                                                       desc);
        }
        bcp->conseccompletes++;
        return FLUSH_COMPLETE;
@@ -563,14 +687,14 @@ static int wait_completion(struct bau_desc *bau_desc,
 {
        int right_shift;
        unsigned long mmr_offset;
-       int cpu = bcp->uvhub_cpu;
+       int desc = bcp->using_desc;
 
-       if (cpu < UV_CPUS_PER_AS) {
+       if (desc < UV_CPUS_PER_AS) {
                mmr_offset = UVH_LB_BAU_SB_ACTIVATION_STATUS_0;
-               right_shift = cpu * UV_ACT_STATUS_SIZE;
+               right_shift = desc * UV_ACT_STATUS_SIZE;
        } else {
                mmr_offset = UVH_LB_BAU_SB_ACTIVATION_STATUS_1;
-               right_shift = ((cpu - UV_CPUS_PER_AS) * UV_ACT_STATUS_SIZE);
+               right_shift = ((desc - UV_CPUS_PER_AS) * UV_ACT_STATUS_SIZE);
        }
 
        if (bcp->uvhub_version == 1)
@@ -752,8 +876,7 @@ static void handle_cmplt(int completion_status, struct bau_desc *bau_desc,
  * Returns 1 if it gives up entirely and the original cpu mask is to be
  * returned to the kernel.
  */
-int uv_flush_send_and_wait(struct bau_desc *bau_desc,
-                       struct cpumask *flush_mask, struct bau_control *bcp)
+int uv_flush_send_and_wait(struct cpumask *flush_mask, struct bau_control *bcp)
 {
        int seq_number = 0;
        int completion_stat = 0;
@@ -766,20 +889,24 @@ int uv_flush_send_and_wait(struct bau_desc *bau_desc,
        struct bau_control *hmaster = bcp->uvhub_master;
        struct uv1_bau_msg_header *uv1_hdr = NULL;
        struct uv2_bau_msg_header *uv2_hdr = NULL;
+       struct bau_desc *bau_desc;
 
-       if (bcp->uvhub_version == 1) {
-               uv1 = 1;
+       if (bcp->uvhub_version == 1)
                uv1_throttle(hmaster, stat);
-               uv1_hdr = &bau_desc->header.uv1_hdr;
-       } else
-               uv2_hdr = &bau_desc->header.uv2_hdr;
 
        while (hmaster->uvhub_quiesce)
                cpu_relax();
 
        time1 = get_cycles();
        do {
-               if (try == 0) {
+               bau_desc = bcp->descriptor_base;
+               bau_desc += (ITEMS_PER_DESC * bcp->using_desc);
+               if (bcp->uvhub_version == 1) {
+                       uv1 = 1;
+                       uv1_hdr = &bau_desc->header.uv1_hdr;
+               } else
+                       uv2_hdr = &bau_desc->header.uv2_hdr;
+               if ((try == 0) || (completion_stat == FLUSH_RETRY_BUSYBUG)) {
                        if (uv1)
                                uv1_hdr->msg_type = MSG_REGULAR;
                        else
@@ -797,13 +924,14 @@ int uv_flush_send_and_wait(struct bau_desc *bau_desc,
                        uv1_hdr->sequence = seq_number;
                else
                        uv2_hdr->sequence = seq_number;
-               index = (1UL << AS_PUSH_SHIFT) | bcp->uvhub_cpu;
+               index = (1UL << AS_PUSH_SHIFT) | bcp->using_desc;
                bcp->send_message = get_cycles();
 
                write_mmr_activation(index);
 
                try++;
                completion_stat = wait_completion(bau_desc, bcp, try);
+               /* UV2: wait_completion() may change the bcp->using_desc */
 
                handle_cmplt(completion_stat, bau_desc, bcp, hmaster, stat);
 
@@ -814,6 +942,7 @@ int uv_flush_send_and_wait(struct bau_desc *bau_desc,
                }
                cpu_relax();
        } while ((completion_stat == FLUSH_RETRY_PLUGGED) ||
+                (completion_stat == FLUSH_RETRY_BUSYBUG) ||
                 (completion_stat == FLUSH_RETRY_TIMEOUT));
 
        time2 = get_cycles();
@@ -828,6 +957,7 @@ int uv_flush_send_and_wait(struct bau_desc *bau_desc,
        record_send_stats(time1, time2, bcp, stat, completion_stat, try);
 
        if (completion_stat == FLUSH_GIVEUP)
+               /* FLUSH_GIVEUP will fall back to using IPI's for tlb flush */
                return 1;
        return 0;
 }
@@ -983,7 +1113,7 @@ const struct cpumask *uv_flush_tlb_others(const struct cpumask *cpumask,
                stat->s_ntargself++;
 
        bau_desc = bcp->descriptor_base;
-       bau_desc += (ITEMS_PER_DESC * bcp->uvhub_cpu);
+       bau_desc += (ITEMS_PER_DESC * bcp->using_desc);
        bau_uvhubs_clear(&bau_desc->distribution, UV_DISTRIBUTION_SIZE);
        if (set_distrib_bits(flush_mask, bcp, bau_desc, &locals, &remotes))
                return NULL;
@@ -996,12 +1126,85 @@ const struct cpumask *uv_flush_tlb_others(const struct cpumask *cpumask,
         * uv_flush_send_and_wait returns 0 if all cpu's were messaged,
         * or 1 if it gave up and the original cpumask should be returned.
         */
-       if (!uv_flush_send_and_wait(bau_desc, flush_mask, bcp))
+       if (!uv_flush_send_and_wait(flush_mask, bcp))
                return NULL;
        else
                return cpumask;
 }
 
+/*
+ * Search the message queue for any 'other' message with the same software
+ * acknowledge resource bit vector.
+ */
+struct bau_pq_entry *find_another_by_swack(struct bau_pq_entry *msg,
+                       struct bau_control *bcp, unsigned char swack_vec)
+{
+       struct bau_pq_entry *msg_next = msg + 1;
+
+       if (msg_next > bcp->queue_last)
+               msg_next = bcp->queue_first;
+       while ((msg_next->swack_vec != 0) && (msg_next != msg)) {
+               if (msg_next->swack_vec == swack_vec)
+                       return msg_next;
+               msg_next++;
+               if (msg_next > bcp->queue_last)
+                       msg_next = bcp->queue_first;
+       }
+       return NULL;
+}
+
+/*
+ * UV2 needs to work around a bug in which an arriving message has not
+ * set a bit in the UVH_LB_BAU_INTD_SOFTWARE_ACKNOWLEDGE register.
+ * Such a message must be ignored.
+ */
+void process_uv2_message(struct msg_desc *mdp, struct bau_control *bcp)
+{
+       unsigned long mmr_image;
+       unsigned char swack_vec;
+       struct bau_pq_entry *msg = mdp->msg;
+       struct bau_pq_entry *other_msg;
+
+       mmr_image = read_mmr_sw_ack();
+       swack_vec = msg->swack_vec;
+
+       if ((swack_vec & mmr_image) == 0) {
+               /*
+                * This message was assigned a swack resource, but no
+                * reserved acknowlegment is pending.
+                * The bug has prevented this message from setting the MMR.
+                * And no other message has used the same sw_ack resource.
+                * Do the requested shootdown but do not reply to the msg.
+                * (the 0 means make no acknowledge)
+                */
+               bau_process_message(mdp, bcp, 0);
+               return;
+       }
+
+       /*
+        * Some message has set the MMR 'pending' bit; it might have been
+        * another message.  Look for that message.
+        */
+       other_msg = find_another_by_swack(msg, bcp, msg->swack_vec);
+       if (other_msg) {
+               /* There is another.  Do not ack the current one. */
+               bau_process_message(mdp, bcp, 0);
+               /*
+                * Let the natural processing of that message acknowledge
+                * it. Don't get the processing of sw_ack's out of order.
+                */
+               return;
+       }
+
+       /*
+        * There is no other message using this sw_ack, so it is safe to
+        * acknowledge it.
+        */
+       bau_process_message(mdp, bcp, 1);
+
+       return;
+}
+
 /*
  * The BAU message interrupt comes here. (registered by set_intr_gate)
  * See entry_64.S
@@ -1038,9 +1241,11 @@ void uv_bau_message_interrupt(struct pt_regs *regs)
                count++;
 
                msgdesc.msg_slot = msg - msgdesc.queue_first;
-               msgdesc.swack_slot = ffs(msg->swack_vec) - 1;
                msgdesc.msg = msg;
-               bau_process_message(&msgdesc, bcp);
+               if (bcp->uvhub_version == 2)
+                       process_uv2_message(&msgdesc, bcp);
+               else
+                       bau_process_message(&msgdesc, bcp, 1);
 
                msg++;
                if (msg > msgdesc.queue_last)
@@ -1158,7 +1363,7 @@ static int ptc_seq_show(struct seq_file *file, void *data)
                seq_printf(file,
                        "all one mult none retry canc nocan reset rcan ");
                seq_printf(file,
-                       "disable enable\n");
+                       "disable enable wars warshw warwaits\n");
        }
        if (cpu < num_possible_cpus() && cpu_online(cpu)) {
                stat = &per_cpu(ptcstats, cpu);
@@ -1189,8 +1394,10 @@ static int ptc_seq_show(struct seq_file *file, void *data)
                           stat->d_nomsg, stat->d_retries, stat->d_canceled,
                           stat->d_nocanceled, stat->d_resets,
                           stat->d_rcanceled);
-               seq_printf(file, "%ld %ld\n",
-                       stat->s_bau_disabled, stat->s_bau_reenabled);
+               seq_printf(file, "%ld %ld %ld %ld %ld\n",
+                       stat->s_bau_disabled, stat->s_bau_reenabled,
+                       stat->s_uv2_wars, stat->s_uv2_wars_hw,
+                       stat->s_uv2_war_waits);
        }
        return 0;
 }
@@ -1564,6 +1771,7 @@ static void pq_init(int node, int pnode)
        write_mmr_payload_first(pnode, pn_first);
        write_mmr_payload_tail(pnode, first);
        write_mmr_payload_last(pnode, last);
+       write_gmmr_sw_ack(pnode, 0xffffUL);
 
        /* in effect, all msg_type's are set to MSG_NOOP */
        memset(pqp, 0, sizeof(struct bau_pq_entry) * DEST_Q_SIZE);
@@ -1651,6 +1859,7 @@ static void __init init_per_cpu_tunables(void)
                bcp->cong_response_us           = congested_respns_us;
                bcp->cong_reps                  = congested_reps;
                bcp->cong_period                = congested_period;
+               bcp->clocks_per_100_usec =      usec_2_cycles(100);
        }
 }
 
@@ -1771,6 +1980,7 @@ static int scan_sock(struct socket_desc *sdp, struct uvhub_desc *bdp,
                }
                bcp->uvhub_master = *hmasterp;
                bcp->uvhub_cpu = uv_cpu_hub_info(cpu)->blade_processor_id;
+               bcp->using_desc = bcp->uvhub_cpu;
                if (bcp->uvhub_cpu >= MAX_CPUS_PER_UVHUB) {
                        printk(KERN_EMERG "%d cpus per uvhub invalid\n",
                                bcp->uvhub_cpu);