x86/platform/uv: Remove UV BAU TLB Shootdown Handler

The Broadcast Assist Unit (BAU) TLB shootdown handler is being rewritten
to become the UV BAU APIC driver. It is designed to speed up sending
IPIs to selective CPUs within the system. Remove the current TLB
shutdown handler (tlb_uv.c) file and a couple of kernel hooks in the
interim.

Signed-off-by: Mike Travis <mike.travis@hpe.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Dimitri Sivanich <dimitri.sivanich@hpe.com>
Link: https://lkml.kernel.org/r/20201005203929.148656-2-mike.travis@hpe.com

2 files changed, 1 insertions, 2098 deletions

diff --git a/arch/x86/platform/uv/Makefile b/arch/x86/platform/uv/Makefile
index a3693c829e2e..224ff0504890 100644
--- a/arch/x86/platform/uv/Makefile
+++ b/arch/x86/platform/uv/Makefile
@@ -1,2 +1,2 @@
 # SPDX-License-Identifier: GPL-2.0-only
-obj-$(CONFIG_X86_UV)		+= tlb_uv.o bios_uv.o uv_irq.o uv_sysfs.o uv_time.o uv_nmi.o
+obj-$(CONFIG_X86_UV)		+= bios_uv.o uv_irq.o uv_sysfs.o uv_time.o uv_nmi.o
diff --git a/arch/x86/platform/uv/tlb_uv.c b/arch/x86/platform/uv/tlb_uv.c
deleted file mode 100644
index 62ea907668f8..000000000000
--- a/arch/x86/platform/uv/tlb_uv.c
+++ /dev/null
@@ -1,2097 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0-or-later
-/*
- *	SGI UltraViolet TLB flush routines.
- *
- *	(c) 2008-2014 Cliff Wickman <cpw@sgi.com>, SGI.
- */
-#include <linux/seq_file.h>
-#include <linux/proc_fs.h>
-#include <linux/debugfs.h>
-#include <linux/kernel.h>
-#include <linux/slab.h>
-#include <linux/delay.h>
-
-#include <asm/mmu_context.h>
-#include <asm/uv/uv.h>
-#include <asm/uv/uv_mmrs.h>
-#include <asm/uv/uv_hub.h>
-#include <asm/uv/uv_bau.h>
-#include <asm/apic.h>
-#include <asm/tsc.h>
-#include <asm/irq_vectors.h>
-#include <asm/timer.h>
-
-static struct bau_operations ops __ro_after_init;
-
-static int timeout_us;
-static bool nobau = true;
-static int nobau_perm;
-
-/* tunables: */
-static int max_concurr		= MAX_BAU_CONCURRENT;
-static int max_concurr_const	= MAX_BAU_CONCURRENT;
-static int plugged_delay	= PLUGGED_DELAY;
-static int plugsb4reset		= PLUGSB4RESET;
-static int giveup_limit		= GIVEUP_LIMIT;
-static int timeoutsb4reset	= TIMEOUTSB4RESET;
-static int ipi_reset_limit	= IPI_RESET_LIMIT;
-static int complete_threshold	= COMPLETE_THRESHOLD;
-static int congested_respns_us	= CONGESTED_RESPONSE_US;
-static int congested_reps	= CONGESTED_REPS;
-static int disabled_period	= DISABLED_PERIOD;
-
-static struct tunables tunables[] = {
-	{&max_concurr,           MAX_BAU_CONCURRENT}, /* must be [0] */
-	{&plugged_delay,         PLUGGED_DELAY},
-	{&plugsb4reset,          PLUGSB4RESET},
-	{&timeoutsb4reset,       TIMEOUTSB4RESET},
-	{&ipi_reset_limit,       IPI_RESET_LIMIT},
-	{&complete_threshold,    COMPLETE_THRESHOLD},
-	{&congested_respns_us,   CONGESTED_RESPONSE_US},
-	{&congested_reps,        CONGESTED_REPS},
-	{&disabled_period,       DISABLED_PERIOD},
-	{&giveup_limit,          GIVEUP_LIMIT}
-};
-
-static struct dentry *tunables_dir;
-
-/* these correspond to the statistics printed by ptc_seq_show() */
-static char *stat_description[] = {
-	"sent:     number of shootdown messages sent",
-	"stime:    time spent sending messages",
-	"numuvhubs: number of hubs targeted with shootdown",
-	"numuvhubs16: number times 16 or more hubs targeted",
-	"numuvhubs8: number times 8 or more hubs targeted",
-	"numuvhubs4: number times 4 or more hubs targeted",
-	"numuvhubs2: number times 2 or more hubs targeted",
-	"numuvhubs1: number times 1 hub targeted",
-	"numcpus:  number of cpus targeted with shootdown",
-	"dto:      number of destination timeouts",
-	"retries:  destination timeout retries sent",
-	"rok:   :  destination timeouts successfully retried",
-	"resetp:   ipi-style resource resets for plugs",
-	"resett:   ipi-style resource resets for timeouts",
-	"giveup:   fall-backs to ipi-style shootdowns",
-	"sto:      number of source timeouts",
-	"bz:       number of stay-busy's",
-	"throt:    number times spun in throttle",
-	"swack:   image of UVH_LB_BAU_INTD_SOFTWARE_ACKNOWLEDGE",
-	"recv:     shootdown messages received",
-	"rtime:    time spent processing messages",
-	"all:      shootdown all-tlb messages",
-	"one:      shootdown one-tlb messages",
-	"mult:     interrupts that found multiple messages",
-	"none:     interrupts that found no messages",
-	"retry:    number of retry messages processed",
-	"canc:     number messages canceled by retries",
-	"nocan:    number retries that found nothing to cancel",
-	"reset:    number of ipi-style reset requests processed",
-	"rcan:     number messages canceled by reset requests",
-	"disable:  number times use of the BAU was disabled",
-	"enable:   number times use of the BAU was re-enabled"
-};
-
-static int __init setup_bau(char *arg)
-{
-	int result;
-
-	if (!arg)
-		return -EINVAL;
-
-	result = strtobool(arg, &nobau);
-	if (result)
-		return result;
-
-	/* we need to flip the logic here, so that bau=y sets nobau to false */
-	nobau = !nobau;
-
-	if (!nobau)
-		pr_info("UV BAU Enabled\n");
-	else
-		pr_info("UV BAU Disabled\n");
-
-	return 0;
-}
-early_param("bau", setup_bau);
-
-/* base pnode in this partition */
-static int uv_base_pnode __read_mostly;
-
-static DEFINE_PER_CPU(struct ptc_stats, ptcstats);
-static DEFINE_PER_CPU(struct bau_control, bau_control);
-static DEFINE_PER_CPU(cpumask_var_t, uv_flush_tlb_mask);
-
-static void
-set_bau_on(void)
-{
-	int cpu;
-	struct bau_control *bcp;
-
-	if (nobau_perm) {
-		pr_info("BAU not initialized; cannot be turned on\n");
-		return;
-	}
-	nobau = false;
-	for_each_present_cpu(cpu) {
-		bcp = &per_cpu(bau_control, cpu);
-		bcp->nobau = false;
-	}
-	pr_info("BAU turned on\n");
-	return;
-}
-
-static void
-set_bau_off(void)
-{
-	int cpu;
-	struct bau_control *bcp;
-
-	nobau = true;
-	for_each_present_cpu(cpu) {
-		bcp = &per_cpu(bau_control, cpu);
-		bcp->nobau = true;
-	}
-	pr_info("BAU turned off\n");
-	return;
-}
-
-/*
- * Determine the first node on a uvhub. 'Nodes' are used for kernel
- * memory allocation.
- */
-static int __init uvhub_to_first_node(int uvhub)
-{
-	int node, b;
-
-	for_each_online_node(node) {
-		b = uv_node_to_blade_id(node);
-		if (uvhub == b)
-			return node;
-	}
-	return -1;
-}
-
-/*
- * Determine the apicid of the first cpu on a uvhub.
- */
-static int __init uvhub_to_first_apicid(int uvhub)
-{
-	int cpu;
-
-	for_each_present_cpu(cpu)
-		if (uvhub == uv_cpu_to_blade_id(cpu))
-			return per_cpu(x86_cpu_to_apicid, cpu);
-	return -1;
-}
-
-/*
- * Free a software acknowledge hardware resource by clearing its Pending
- * bit. This will return a reply to the sender.
- * If the message has timed out, a reply has already been sent by the
- * hardware but the resource has not been released. In that case our
- * 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,
-						int do_acknowledge)
-{
-	unsigned long dw;
-	struct bau_pq_entry *msg;
-
-	msg = mdp->msg;
-	if (!msg->canceled && do_acknowledge) {
-		dw = (msg->swack_vec << UV_SW_ACK_NPENDING) | msg->swack_vec;
-		ops.write_l_sw_ack(dw);
-	}
-	msg->replied_to = 1;
-	msg->swack_vec = 0;
-}
-
-/*
- * Process the receipt of a RETRY message
- */
-static void bau_process_retry_msg(struct msg_desc *mdp,
-					struct bau_control *bcp)
-{
-	int i;
-	int cancel_count = 0;
-	unsigned long msg_res;
-	unsigned long mmr = 0;
-	struct bau_pq_entry *msg = mdp->msg;
-	struct bau_pq_entry *msg2;
-	struct ptc_stats *stat = bcp->statp;
-
-	stat->d_retries++;
-	/*
-	 * cancel any message from msg+1 to the retry itself
-	 */
-	for (msg2 = msg+1, i = 0; i < DEST_Q_SIZE; msg2++, i++) {
-		if (msg2 > mdp->queue_last)
-			msg2 = mdp->queue_first;
-		if (msg2 == msg)
-			break;
-
-		/* same conditions for cancellation as do_reset */
-		if ((msg2->replied_to == 0) && (msg2->canceled == 0) &&
-		    (msg2->swack_vec) && ((msg2->swack_vec &
-			msg->swack_vec) == 0) &&
-		    (msg2->sending_cpu == msg->sending_cpu) &&
-		    (msg2->msg_type != MSG_NOOP)) {
-			mmr = ops.read_l_sw_ack();
-			msg_res = msg2->swack_vec;
-			/*
-			 * This is a message retry; clear the resources held
-			 * by the previous message only if they timed out.
-			 * If it has not timed out we have an unexpected
-			 * situation to report.
-			 */
-			if (mmr & (msg_res << UV_SW_ACK_NPENDING)) {
-				unsigned long mr;
-				/*
-				 * Is the resource timed out?
-				 * Make everyone ignore the cancelled message.
-				 */
-				msg2->canceled = 1;
-				stat->d_canceled++;
-				cancel_count++;
-				mr = (msg_res << UV_SW_ACK_NPENDING) | msg_res;
-				ops.write_l_sw_ack(mr);
-			}
-		}
-	}
-	if (!cancel_count)
-		stat->d_nocanceled++;
-}
-
-/*
- * 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,
-						int do_acknowledge)
-{
-	short socket_ack_count = 0;
-	short *sp;
-	struct atomic_short *asp;
-	struct ptc_stats *stat = bcp->statp;
-	struct bau_pq_entry *msg = mdp->msg;
-	struct bau_control *smaster = bcp->socket_master;
-
-	/*
-	 * This must be a normal message, or retry of a normal message
-	 */
-	if (msg->address == TLB_FLUSH_ALL) {
-		flush_tlb_local();
-		stat->d_alltlb++;
-	} else {
-		flush_tlb_one_user(msg->address);
-		stat->d_onetlb++;
-	}
-	stat->d_requestee++;
-
-	/*
-	 * One cpu on each uvhub has the additional job on a RETRY
-	 * of releasing the resource held by the message that is
-	 * being retried.  That message is identified by sending
-	 * cpu number.
-	 */
-	if (msg->msg_type == MSG_RETRY && bcp == bcp->uvhub_master)
-		bau_process_retry_msg(mdp, bcp);
-
-	/*
-	 * This is a swack message, so we have to reply to it.
-	 * Count each responding cpu on the socket. This avoids
-	 * pinging the count's cache line back and forth between
-	 * the sockets.
-	 */
-	sp = &smaster->socket_acknowledge_count[mdp->msg_slot];
-	asp = (struct atomic_short *)sp;
-	socket_ack_count = atom_asr(1, asp);
-	if (socket_ack_count == bcp->cpus_in_socket) {
-		int msg_ack_count;
-		/*
-		 * Both sockets dump their completed count total into
-		 * the message's count.
-		 */
-		*sp = 0;
-		asp = (struct atomic_short *)&msg->acknowledge_count;
-		msg_ack_count = atom_asr(socket_ack_count, asp);
-
-		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, do_acknowledge);
-		}
-	}
-
-	return;
-}
-
-/*
- * Determine the first cpu on a pnode.
- */
-static int pnode_to_first_cpu(int pnode, struct bau_control *smaster)
-{
-	int cpu;
-	struct hub_and_pnode *hpp;
-
-	for_each_present_cpu(cpu) {
-		hpp = &smaster->thp[cpu];
-		if (pnode == hpp->pnode)
-			return cpu;
-	}
-	return -1;
-}
-
-/*
- * Last resort when we get a large number of destination timeouts is
- * to clear resources held by a given cpu.
- * Do this with IPI so that all messages in the BAU message queue
- * can be identified by their nonzero swack_vec field.
- *
- * This is entered for a single cpu on the uvhub.
- * The sender want's this uvhub to free a specific message's
- * swack resources.
- */
-static void do_reset(void *ptr)
-{
-	int i;
-	struct bau_control *bcp = &per_cpu(bau_control, smp_processor_id());
-	struct reset_args *rap = (struct reset_args *)ptr;
-	struct bau_pq_entry *msg;
-	struct ptc_stats *stat = bcp->statp;
-
-	stat->d_resets++;
-	/*
-	 * We're looking for the given sender, and
-	 * will free its swack resource.
-	 * If all cpu's finally responded after the timeout, its
-	 * message 'replied_to' was set.
-	 */
-	for (msg = bcp->queue_first, i = 0; i < DEST_Q_SIZE; msg++, i++) {
-		unsigned long msg_res;
-		/* do_reset: same conditions for cancellation as
-		   bau_process_retry_msg() */
-		if ((msg->replied_to == 0) &&
-		    (msg->canceled == 0) &&
-		    (msg->sending_cpu == rap->sender) &&
-		    (msg->swack_vec) &&
-		    (msg->msg_type != MSG_NOOP)) {
-			unsigned long mmr;
-			unsigned long mr;
-			/*
-			 * make everyone else ignore this message
-			 */
-			msg->canceled = 1;
-			/*
-			 * only reset the resource if it is still pending
-			 */
-			mmr = ops.read_l_sw_ack();
-			msg_res = msg->swack_vec;
-			mr = (msg_res << UV_SW_ACK_NPENDING) | msg_res;
-			if (mmr & msg_res) {
-				stat->d_rcanceled++;
-				ops.write_l_sw_ack(mr);
-			}
-		}
-	}
-	return;
-}
-
-/*
- * Use IPI to get all target uvhubs to release resources held by
- * a given sending cpu number.
- */
-static void reset_with_ipi(struct pnmask *distribution, struct bau_control *bcp)
-{
-	int pnode;
-	int apnode;
-	int maskbits;
-	int sender = bcp->cpu;
-	cpumask_t *mask = bcp->uvhub_master->cpumask;
-	struct bau_control *smaster = bcp->socket_master;
-	struct reset_args reset_args;
-
-	reset_args.sender = sender;
-	cpumask_clear(mask);
-	/* find a single cpu for each uvhub in this distribution mask */
-	maskbits = sizeof(struct pnmask) * BITSPERBYTE;
-	/* each bit is a pnode relative to the partition base pnode */
-	for (pnode = 0; pnode < maskbits; pnode++) {
-		int cpu;
-		if (!bau_uvhub_isset(pnode, distribution))
-			continue;
-		apnode = pnode + bcp->partition_base_pnode;
-		cpu = pnode_to_first_cpu(apnode, smaster);
-		cpumask_set_cpu(cpu, mask);
-	}
-
-	/* IPI all cpus; preemption is already disabled */
-	smp_call_function_many(mask, do_reset, (void *)&reset_args, 1);
-	return;
-}
-
-/*
- * Not to be confused with cycles_2_ns() from tsc.c; this gives a relative
- * number, not an absolute. It converts a duration in cycles to a duration in
- * ns.
- */
-static inline unsigned long long cycles_2_ns(unsigned long long cyc)
-{
-	struct cyc2ns_data data;
-	unsigned long long ns;
-
-	cyc2ns_read_begin(&data);
-	ns = mul_u64_u32_shr(cyc, data.cyc2ns_mul, data.cyc2ns_shift);
-	cyc2ns_read_end();
-
-	return ns;
-}
-
-/*
- * The reverse of the above; converts a duration in ns to a duration in cycles.
- */
-static inline unsigned long long ns_2_cycles(unsigned long long ns)
-{
-	struct cyc2ns_data data;
-	unsigned long long cyc;
-
-	cyc2ns_read_begin(&data);
-	cyc = (ns << data.cyc2ns_shift) / data.cyc2ns_mul;
-	cyc2ns_read_end();
-
-	return cyc;
-}
-
-static inline unsigned long cycles_2_us(unsigned long long cyc)
-{
-	return cycles_2_ns(cyc) / NSEC_PER_USEC;
-}
-
-static inline cycles_t sec_2_cycles(unsigned long sec)
-{
-	return ns_2_cycles(sec * NSEC_PER_SEC);
-}
-
-static inline unsigned long long usec_2_cycles(unsigned long usec)
-{
-	return ns_2_cycles(usec * NSEC_PER_USEC);
-}
-
-/*
- * wait for all cpus on this hub to finish their sends and go quiet
- * leaves uvhub_quiesce set so that no new broadcasts are started by
- * bau_flush_send_and_wait()
- */
-static inline void quiesce_local_uvhub(struct bau_control *hmaster)
-{
-	atom_asr(1, (struct atomic_short *)&hmaster->uvhub_quiesce);
-}
-
-/*
- * mark this quiet-requestor as done
- */
-static inline void end_uvhub_quiesce(struct bau_control *hmaster)
-{
-	atom_asr(-1, (struct atomic_short *)&hmaster->uvhub_quiesce);
-}
-
-/*
- * UV2 could have an extra bit of status in the ACTIVATION_STATUS_2 register.
- * But not currently used.
- */
-static unsigned long uv2_3_read_status(unsigned long offset, int rshft, int desc)
-{
-	return ((read_lmmr(offset) >> rshft) & UV_ACT_STATUS_MASK) << 1;
-}
-
-/*
- * Entered when a bau descriptor has gone into a permanent busy wait because
- * of a hardware bug.
- * Workaround the bug.
- */
-static int handle_uv2_busy(struct bau_control *bcp)
-{
-	struct ptc_stats *stat = bcp->statp;
-
-	stat->s_uv2_wars++;
-	bcp->busy = 1;
-	return FLUSH_GIVEUP;
-}
-
-static int uv2_3_wait_completion(struct bau_desc *bau_desc,
-				struct bau_control *bcp, long try)
-{
-	unsigned long descriptor_stat;
-	cycles_t ttm;
-	u64 mmr_offset = bcp->status_mmr;
-	int right_shift = bcp->status_index;
-	int desc = bcp->uvhub_cpu;
-	long busy_reps = 0;
-	struct ptc_stats *stat = bcp->statp;
-
-	descriptor_stat = uv2_3_read_status(mmr_offset, right_shift, desc);
-
-	/* spin on the status MMR, waiting for it to go idle */
-	while (descriptor_stat != UV2H_DESC_IDLE) {
-		if (descriptor_stat == UV2H_DESC_SOURCE_TIMEOUT) {
-			/*
-			 * A h/w bug on the destination side may
-			 * have prevented the message being marked
-			 * pending, thus it doesn't get replied to
-			 * and gets continually nacked until it times
-			 * out with a SOURCE_TIMEOUT.
-			 */
-			stat->s_stimeout++;
-			return FLUSH_GIVEUP;
-		} else if (descriptor_stat == UV2H_DESC_DEST_TIMEOUT) {
-			ttm = get_cycles();
-
-			/*
-			 * Our retries may be blocked by all destination
-			 * swack resources being consumed, and a timeout
-			 * pending.  In that case hardware returns the
-			 * ERROR that looks like a destination timeout.
-			 * Without using the extended status we have to
-			 * deduce from the short time that this was a
-			 * strong nack.
-			 */
-			if (cycles_2_us(ttm - bcp->send_message) < timeout_us) {
-				bcp->conseccompletes = 0;
-				stat->s_plugged++;
-				/* FLUSH_RETRY_PLUGGED causes hang on boot */
-				return FLUSH_GIVEUP;
-			}
-			stat->s_dtimeout++;
-			bcp->conseccompletes = 0;
-			/* FLUSH_RETRY_TIMEOUT causes hang on boot */
-			return FLUSH_GIVEUP;
-		} 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->timeout_interval)
-					return handle_uv2_busy(bcp);
-			}
-			/*
-			 * descriptor_stat is still BUSY
-			 */
-			cpu_relax();
-		}
-		descriptor_stat = uv2_3_read_status(mmr_offset, right_shift, desc);
-	}
-	bcp->conseccompletes++;
-	return FLUSH_COMPLETE;
-}
-
-/*
- * Returns the status of current BAU message for cpu desc as a bit field
- * [Error][Busy][Aux]
- */
-static u64 read_status(u64 status_mmr, int index, int desc)
-{
-	u64 stat;
-
-	stat = ((read_lmmr(status_mmr) >> index) & UV_ACT_STATUS_MASK) << 1;
-	stat |= (read_lmmr(UVH_LB_BAU_SB_ACTIVATION_STATUS_2) >> desc) & 0x1;
-
-	return stat;
-}
-
-static int uv4_wait_completion(struct bau_desc *bau_desc,
-				struct bau_control *bcp, long try)
-{
-	struct ptc_stats *stat = bcp->statp;
-	u64 descriptor_stat;
-	u64 mmr = bcp->status_mmr;
-	int index = bcp->status_index;
-	int desc = bcp->uvhub_cpu;
-
-	descriptor_stat = read_status(mmr, index, desc);
-
-	/* spin on the status MMR, waiting for it to go idle */
-	while (descriptor_stat != UV2H_DESC_IDLE) {
-		switch (descriptor_stat) {
-		case UV2H_DESC_SOURCE_TIMEOUT:
-			stat->s_stimeout++;
-			return FLUSH_GIVEUP;
-
-		case UV2H_DESC_DEST_TIMEOUT:
-			stat->s_dtimeout++;
-			bcp->conseccompletes = 0;
-			return FLUSH_RETRY_TIMEOUT;
-
-		case UV2H_DESC_DEST_STRONG_NACK:
-			stat->s_plugged++;
-			bcp->conseccompletes = 0;
-			return FLUSH_RETRY_PLUGGED;
-
-		case UV2H_DESC_DEST_PUT_ERR:
-			bcp->conseccompletes = 0;
-			return FLUSH_GIVEUP;
-
-		default:
-			/* descriptor_stat is still BUSY */
-			cpu_relax();
-		}
-		descriptor_stat = read_status(mmr, index, desc);
-	}
-	bcp->conseccompletes++;
-	return FLUSH_COMPLETE;
-}
-
-/*
- * Our retries are blocked by all destination sw ack resources being
- * in use, and a timeout is pending. In that case hardware immediately
- * returns the ERROR that looks like a destination timeout.
- */
-static void destination_plugged(struct bau_desc *bau_desc,
-			struct bau_control *bcp,
-			struct bau_control *hmaster, struct ptc_stats *stat)
-{
-	udelay(bcp->plugged_delay);
-	bcp->plugged_tries++;
-
-	if (bcp->plugged_tries >= bcp->plugsb4reset) {
-		bcp->plugged_tries = 0;
-
-		quiesce_local_uvhub(hmaster);
-
-		spin_lock(&hmaster->queue_lock);
-		reset_with_ipi(&bau_desc->distribution, bcp);
-		spin_unlock(&hmaster->queue_lock);
-
-		end_uvhub_quiesce(hmaster);
-
-		bcp->ipi_attempts++;
-		stat->s_resets_plug++;
-	}
-}
-
-static void destination_timeout(struct bau_desc *bau_desc,
-			struct bau_control *bcp, struct bau_control *hmaster,
-			struct ptc_stats *stat)
-{
-	hmaster->max_concurr = 1;
-	bcp->timeout_tries++;
-	if (bcp->timeout_tries >= bcp->timeoutsb4reset) {
-		bcp->timeout_tries = 0;
-
-		quiesce_local_uvhub(hmaster);
-
-		spin_lock(&hmaster->queue_lock);
-		reset_with_ipi(&bau_desc->distribution, bcp);
-		spin_unlock(&hmaster->queue_lock);
-
-		end_uvhub_quiesce(hmaster);
-
-		bcp->ipi_attempts++;
-		stat->s_resets_timeout++;
-	}
-}
-
-/*
- * Stop all cpus on a uvhub from using the BAU for a period of time.
- * This is reversed by check_enable.
- */
-static void disable_for_period(struct bau_control *bcp, struct ptc_stats *stat)
-{
-	int tcpu;
-	struct bau_control *tbcp;
-	struct bau_control *hmaster;
-	cycles_t tm1;
-
-	hmaster = bcp->uvhub_master;
-	spin_lock(&hmaster->disable_lock);
-	if (!bcp->baudisabled) {
-		stat->s_bau_disabled++;
-		tm1 = get_cycles();
-		for_each_present_cpu(tcpu) {
-			tbcp = &per_cpu(bau_control, tcpu);
-			if (tbcp->uvhub_master == hmaster) {
-				tbcp->baudisabled = 1;
-				tbcp->set_bau_on_time =
-					tm1 + bcp->disabled_period;
-			}
-		}
-	}
-	spin_unlock(&hmaster->disable_lock);
-}
-
-static void count_max_concurr(int stat, struct bau_control *bcp,
-				struct bau_control *hmaster)
-{
-	bcp->plugged_tries = 0;
-	bcp->timeout_tries = 0;
-	if (stat != FLUSH_COMPLETE)
-		return;
-	if (bcp->conseccompletes <= bcp->complete_threshold)
-		return;
-	if (hmaster->max_concurr >= hmaster->max_concurr_const)
-		return;
-	hmaster->max_concurr++;
-}
-
-static void record_send_stats(cycles_t time1, cycles_t time2,
-		struct bau_control *bcp, struct ptc_stats *stat,
-		int completion_status, int try)
-{
-	cycles_t elapsed;
-
-	if (time2 > time1) {
-		elapsed = time2 - time1;
-		stat->s_time += elapsed;
-
-		if ((completion_status == FLUSH_COMPLETE) && (try == 1)) {
-			bcp->period_requests++;
-			bcp->period_time += elapsed;
-			if ((elapsed > usec_2_cycles(bcp->cong_response_us)) &&
-			    (bcp->period_requests > bcp->cong_reps) &&
-			    ((bcp->period_time / bcp->period_requests) >
-					usec_2_cycles(bcp->cong_response_us))) {
-				stat->s_congested++;
-				disable_for_period(bcp, stat);
-			}
-		}
-	} else
-		stat->s_requestor--;
-
-	if (completion_status == FLUSH_COMPLETE && try > 1)
-		stat->s_retriesok++;
-	else if (completion_status == FLUSH_GIVEUP) {
-		stat->s_giveup++;
-		if (get_cycles() > bcp->period_end)
-			bcp->period_giveups = 0;
-		bcp->period_giveups++;
-		if (bcp->period_giveups == 1)
-			bcp->period_end = get_cycles() + bcp->disabled_period;
-		if (bcp->period_giveups > bcp->giveup_limit) {
-			disable_for_period(bcp, stat);
-			stat->s_giveuplimit++;
-		}
-	}
-}
-
-/*
- * Handle the completion status of a message send.
- */
-static void handle_cmplt(int completion_status, struct bau_desc *bau_desc,
-			struct bau_control *bcp, struct bau_control *hmaster,
-			struct ptc_stats *stat)
-{
-	if (completion_status == FLUSH_RETRY_PLUGGED)
-		destination_plugged(bau_desc, bcp, hmaster, stat);
-	else if (completion_status == FLUSH_RETRY_TIMEOUT)
-		destination_timeout(bau_desc, bcp, hmaster, stat);
-}
-
-/*
- * Send a broadcast and wait for it to complete.
- *
- * The flush_mask contains the cpus the broadcast is to be sent to including
- * cpus that are on the local uvhub.
- *
- * Returns 0 if all flushing represented in the mask was done.
- * Returns 1 if it gives up entirely and the original cpu mask is to be
- * returned to the kernel.
- */
-static int uv_flush_send_and_wait(struct cpumask *flush_mask,
-				  struct bau_control *bcp,
-				  struct bau_desc *bau_desc)
-{
-	int seq_number = 0;
-	int completion_stat = 0;
-	long try = 0;
-	unsigned long index;
-	cycles_t time1;
-	cycles_t time2;
-	struct ptc_stats *stat = bcp->statp;
-	struct bau_control *hmaster = bcp->uvhub_master;
-	struct uv2_3_bau_msg_header *uv2_3_hdr = NULL;
-
-	while (hmaster->uvhub_quiesce)
-		cpu_relax();
-
-	time1 = get_cycles();
-	uv2_3_hdr = &bau_desc->header.uv2_3_hdr;
-
-	do {
-		if (try == 0) {
-			uv2_3_hdr->msg_type = MSG_REGULAR;
-			seq_number = bcp->message_number++;
-		} else {
-			uv2_3_hdr->msg_type = MSG_RETRY;
-			stat->s_retry_messages++;
-		}
-
-		uv2_3_hdr->sequence = seq_number;
-		index = (1UL << AS_PUSH_SHIFT) | bcp->uvhub_cpu;
-		bcp->send_message = get_cycles();
-
-		write_mmr_activation(index);
-
-		try++;
-		completion_stat = ops.wait_completion(bau_desc, bcp, try);
-
-		handle_cmplt(completion_stat, bau_desc, bcp, hmaster, stat);
-
-		if (bcp->ipi_attempts >= bcp->ipi_reset_limit) {
-			bcp->ipi_attempts = 0;
-			stat->s_overipilimit++;
-			completion_stat = FLUSH_GIVEUP;
-			break;
-		}
-		cpu_relax();
-	} while ((completion_stat == FLUSH_RETRY_PLUGGED) ||
-		 (completion_stat == FLUSH_RETRY_TIMEOUT));
-
-	time2 = get_cycles();
-
-	count_max_concurr(completion_stat, bcp, hmaster);
-
-	while (hmaster->uvhub_quiesce)
-		cpu_relax();
-
-	atomic_dec(&hmaster->active_descriptor_count);
-
-	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;
-}
-
-/*
- * The BAU is disabled for this uvhub. When the disabled time period has
- * expired re-enable it.
- * Return 0 if it is re-enabled for all cpus on this uvhub.
- */
-static int check_enable(struct bau_control *bcp, struct ptc_stats *stat)
-{
-	int tcpu;
-	struct bau_control *tbcp;
-	struct bau_control *hmaster;
-
-	hmaster = bcp->uvhub_master;
-	spin_lock(&hmaster->disable_lock);
-	if (bcp->baudisabled && (get_cycles() >= bcp->set_bau_on_time)) {
-		stat->s_bau_reenabled++;
-		for_each_present_cpu(tcpu) {
-			tbcp = &per_cpu(bau_control, tcpu);
-			if (tbcp->uvhub_master == hmaster) {
-				tbcp->baudisabled = 0;
-				tbcp->period_requests = 0;
-				tbcp->period_time = 0;
-				tbcp->period_giveups = 0;
-			}
-		}
-		spin_unlock(&hmaster->disable_lock);
-		return 0;
-	}
-	spin_unlock(&hmaster->disable_lock);
-	return -1;
-}
-
-static void record_send_statistics(struct ptc_stats *stat, int locals, int hubs,
-				int remotes, struct bau_desc *bau_desc)
-{
-	stat->s_requestor++;
-	stat->s_ntargcpu += remotes + locals;
-	stat->s_ntargremotes += remotes;
-	stat->s_ntarglocals += locals;
-
-	/* uvhub statistics */
-	hubs = bau_uvhub_weight(&bau_desc->distribution);
-	if (locals) {
-		stat->s_ntarglocaluvhub++;
-		stat->s_ntargremoteuvhub += (hubs - 1);
-	} else
-		stat->s_ntargremoteuvhub += hubs;
-
-	stat->s_ntarguvhub += hubs;
-
-	if (hubs >= 16)
-		stat->s_ntarguvhub16++;
-	else if (hubs >= 8)
-		stat->s_ntarguvhub8++;
-	else if (hubs >= 4)
-		stat->s_ntarguvhub4++;
-	else if (hubs >= 2)
-		stat->s_ntarguvhub2++;
-	else
-		stat->s_ntarguvhub1++;
-}
-
-/*
- * Translate a cpu mask to the uvhub distribution mask in the BAU
- * activation descriptor.
- */
-static int set_distrib_bits(struct cpumask *flush_mask, struct bau_control *bcp,
-			struct bau_desc *bau_desc, int *localsp, int *remotesp)
-{
-	int cpu;
-	int pnode;
-	int cnt = 0;
-	struct hub_and_pnode *hpp;
-
-	for_each_cpu(cpu, flush_mask) {
-		/*
-		 * The distribution vector is a bit map of pnodes, relative
-		 * to the partition base pnode (and the partition base nasid
-		 * in the header).
-		 * Translate cpu to pnode and hub using a local memory array.
-		 */
-		hpp = &bcp->socket_master->thp[cpu];
-		pnode = hpp->pnode - bcp->partition_base_pnode;
-		bau_uvhub_set(pnode, &bau_desc->distribution);
-		cnt++;
-		if (hpp->uvhub == bcp->uvhub)
-			(*localsp)++;
-		else
-			(*remotesp)++;
-	}
-	if (!cnt)
-		return 1;
-	return 0;
-}
-
-/*
- * globally purge translation cache of a virtual address or all TLB's
- * @cpumask: mask of all cpu's in which the address is to be removed
- * @mm: mm_struct containing virtual address range
- * @start: start virtual address to be removed from TLB
- * @end: end virtual address to be remove from TLB
- * @cpu: the current cpu
- *
- * This is the entry point for initiating any UV global TLB shootdown.
- *
- * Purges the translation caches of all specified processors of the given
- * virtual address, or purges all TLB's on specified processors.
- *
- * The caller has derived the cpumask from the mm_struct.  This function
- * is called only if there are bits set in the mask. (e.g. flush_tlb_page())
- *
- * The cpumask is converted into a uvhubmask of the uvhubs containing
- * those cpus.
- *
- * Note that this function should be called with preemption disabled.
- *
- * Returns NULL if all remote flushing was done.
- * Returns pointer to cpumask if some remote flushing remains to be
- * done.  The returned pointer is valid till preemption is re-enabled.
- */
-const struct cpumask *uv_flush_tlb_others(const struct cpumask *cpumask,
-					  const struct flush_tlb_info *info)
-{
-	unsigned int cpu = smp_processor_id();
-	int locals = 0, remotes = 0, hubs = 0;
-	struct bau_desc *bau_desc;
-	struct cpumask *flush_mask;
-	struct ptc_stats *stat;
-	struct bau_control *bcp;
-	unsigned long descriptor_status, status, address;
-
-	bcp = &per_cpu(bau_control, cpu);
-
-	if (bcp->nobau)
-		return cpumask;
-
-	stat = bcp->statp;
-	stat->s_enters++;
-
-	if (bcp->busy) {
-		descriptor_status =
-			read_lmmr(UVH_LB_BAU_SB_ACTIVATION_STATUS_0);
-		status = ((descriptor_status >> (bcp->uvhub_cpu *
-			UV_ACT_STATUS_SIZE)) & UV_ACT_STATUS_MASK) << 1;
-		if (status == UV2H_DESC_BUSY)
-			return cpumask;
-		bcp->busy = 0;
-	}
-
-	/* bau was disabled due to slow response */
-	if (bcp->baudisabled) {
-		if (check_enable(bcp, stat)) {
-			stat->s_ipifordisabled++;
-			return cpumask;
-		}
-	}
-
-	/*
-	 * Each sending cpu has a per-cpu mask which it fills from the caller's
-	 * cpu mask.  All cpus are converted to uvhubs and copied to the
-	 * activation descriptor.
-	 */
-	flush_mask = (struct cpumask *)per_cpu(uv_flush_tlb_mask, cpu);
-	/* don't actually do a shootdown of the local cpu */
-	cpumask_andnot(flush_mask, cpumask, cpumask_of(cpu));
-
-	if (cpumask_test_cpu(cpu, cpumask))
-		stat->s_ntargself++;
-
-	bau_desc = bcp->descriptor_base;
-	bau_desc += (ITEMS_PER_DESC * bcp->uvhub_cpu);
-	bau_uvhubs_clear(&bau_desc->distribution, UV_DISTRIBUTION_SIZE);
-	if (set_distrib_bits(flush_mask, bcp, bau_desc, &locals, &remotes))
-		return NULL;
-
-	record_send_statistics(stat, locals, hubs, remotes, bau_desc);
-
-	if (!info->end || (info->end - info->start) <= PAGE_SIZE)
-		address = info->start;
-	else
-		address = TLB_FLUSH_ALL;
-
-	switch (bcp->uvhub_version) {
-	case UV_BAU_V2:
-	case UV_BAU_V3:
-		bau_desc->payload.uv2_3.address = address;
-		bau_desc->payload.uv2_3.sending_cpu = cpu;
-		break;
-	case UV_BAU_V4:
-		bau_desc->payload.uv4.address = address;
-		bau_desc->payload.uv4.sending_cpu = cpu;
-		bau_desc->payload.uv4.qualifier = BAU_DESC_QUALIFIER;
-		break;
-	}
-
-	/*
-	 * 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(flush_mask, bcp, bau_desc))
-		return NULL;
-	else
-		return cpumask;
-}
-
-/*
- * Search the message queue for any 'other' unprocessed message with the
- * same software acknowledge resource bit vector as the 'msg' message.
- */
-static struct bau_pq_entry *find_another_by_swack(struct bau_pq_entry *msg,
-						  struct bau_control *bcp)
-{
-	struct bau_pq_entry *msg_next = msg + 1;
-	unsigned char swack_vec = msg->swack_vec;
-
-	if (msg_next > bcp->queue_last)
-		msg_next = bcp->queue_first;
-	while (msg_next != msg) {
-		if ((msg_next->canceled == 0) && (msg_next->replied_to == 0) &&
-				(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.
- */
-static 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 = ops.read_l_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.