patch-2.4.19 linux-2.4.19/arch/ia64/sn/kernel/sn1/sn1_smp.c

• Lines: 475
• Date: Fri Aug 2 17:39:43 2002
• Orig file: linux-2.4.18/arch/ia64/sn/kernel/sn1/sn1_smp.c
• Orig date: Wed Dec 31 16:00:00 1969

diff -urN linux-2.4.18/arch/ia64/sn/kernel/sn1/sn1_smp.c linux-2.4.19/arch/ia64/sn/kernel/sn1/sn1_smp.c
@@ -0,0 +1,474 @@
+/*
+ * SN1 Platform specific SMP Support
+ *
+ * Copyright (C) 2000-2002 Silicon Graphics, Inc. All rights reserved.
+ * 
+ * This program is free software; you can redistribute it and/or modify it 
+ * under the terms of version 2 of the GNU General Public License 
+ * as published by the Free Software Foundation.
+ * 
+ * This program is distributed in the hope that it would be useful, but 
+ * WITHOUT ANY WARRANTY; without even the implied warranty of 
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 
+ * 
+ * Further, this software is distributed without any warranty that it is 
+ * free of the rightful claim of any third person regarding infringement 
+ * or the like.  Any license provided herein, whether implied or 
+ * otherwise, applies only to this software file.  Patent licenses, if 
+ * any, provided herein do not apply to combinations of this program with 
+ * other software, or any other product whatsoever.
+ * 
+ * You should have received a copy of the GNU General Public 
+ * License along with this program; if not, write the Free Software 
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston MA 02111-1307, USA.
+ * 
+ * Contact information:  Silicon Graphics, Inc., 1600 Amphitheatre Pkwy, 
+ * Mountain View, CA  94043, or:
+ * 
+ * http://www.sgi.com 
+ * 
+ * For further information regarding this notice, see: 
+ * 
+ * http://oss.sgi.com/projects/GenInfo/NoticeExplan
+ */
+
+#include <linux/config.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/spinlock.h>
+#include <linux/threads.h>
+#include <linux/sched.h>
+#include <linux/smp.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/mmzone.h>
+
+#include <asm/processor.h>
+#include <asm/irq.h>
+#include <asm/sal.h>
+#include <asm/system.h>
+#include <asm/io.h>
+#include <asm/smp.h>
+#include <asm/hw_irq.h>
+#include <asm/current.h>
+#include <asm/delay.h>
+#include <asm/sn/sn_cpuid.h>
+
+/*
+ * The following structure is used to pass params thru smp_call_function
+ * to other cpus for flushing TLB ranges.
+ */
+typedef struct {
+	unsigned long	start;
+	unsigned long	end;
+	unsigned long	nbits;
+	unsigned int	rid;
+	atomic_t	unfinished_count;
+} ptc_params_t;
+
+#define NUMPTC	512
+
+static ptc_params_t	ptcParamArray[NUMPTC] __attribute__((__aligned__(128)));
+
+/* use separate cache lines on ptcParamsNextByCpu to avoid false sharing */
+static ptc_params_t	*ptcParamsNextByCpu[NR_CPUS*16] __attribute__((__aligned__(128)));
+static volatile ptc_params_t	*ptcParamsEmpty __cacheline_aligned;
+
+/*REFERENCED*/
+static spinlock_t ptcParamsLock __cacheline_aligned = SPIN_LOCK_UNLOCKED;
+
+static int ptcInit = 0;
+#ifdef PTCDEBUG
+static int ptcParamsAllBusy = 0;		/* debugging/statistics */
+static int ptcCountBacklog = 0;
+static int ptcBacklog[NUMPTC+1];
+static char ptcParamsCounts[NR_CPUS][NUMPTC] __attribute__((__aligned__(128)));
+static char ptcParamsResults[NR_CPUS][NUMPTC] __attribute__((__aligned__(128)));
+#endif
+
+/*
+ * Make smp_send_flush_tlbsmp_send_flush_tlb() a weak reference,
+ * so that we get a clean compile with the ia64 patch without the
+ * actual SN1 specific code in arch/ia64/kernel/smp.c.
+ */
+extern void smp_send_flush_tlb (void) __attribute((weak));
+
+/*
+ * The following table/struct is for remembering PTC coherency domains. It
+ * is also used to translate sapicid into cpuids. We dont want to start 
+ * cpus unless we know their cache domain.
+ */
+#ifdef PTC_NOTYET
+sn_sapicid_info_t	sn_sapicid_info[NR_CPUS];
+#endif
+
+/**
+ * sn1_ptc_l_range - purge local translation cache
+ * @start: start of virtual address range
+ * @end: end of virtual address range
+ * @nbits: specifies number of bytes to purge per instruction (num = 1<<(nbits & 0xfc))
+ *
+ * Purges the range specified from the local processor's translation cache
+ * (as opposed to the translation registers).  Note that more than the specified
+ * range *may* be cleared from the cache by some processors.
+ *
+ * This is probably not good enough, but I don't want to try to make it better 
+ * until I get some statistics on a running system. At a minimum, we should only 
+ * send IPIs to 1 processor in each TLB domain & have it issue a ptc.g on it's 
+ * own FSB. Also, we only have to serialize per FSB, not globally.
+ *
+ * More likely, we will have to do some work to reduce the frequency of calls to
+ * this routine.
+ */
+static inline void
+sn1_ptc_l_range(unsigned long start, unsigned long end, unsigned long nbits)
+{
+	do {
+		__asm__ __volatile__ ("ptc.l %0,%1" :: "r"(start), "r"(nbits<<2) : "memory");
+		start += (1UL << nbits);
+	} while (start < end);
+	ia64_srlz_d();
+}
+
+/**
+ * sn1_received_flush_tlb - cpu tlb flush routine
+ *
+ * Flushes the TLB of a given processor.
+ */
+void
+sn1_received_flush_tlb(void)
+{
+	unsigned long	start, end, nbits;
+	unsigned int	rid, saved_rid;
+	int		cpu = smp_processor_id();
+	int		result;
+	ptc_params_t	*ptcParams;
+
+	ptcParams = ptcParamsNextByCpu[cpu*16];
+	if (ptcParams == ptcParamsEmpty)
+		return;
+
+	do {
+		start = ptcParams->start;
+		saved_rid = (unsigned int) ia64_get_rr(start);
+		end = ptcParams->end;
+		nbits = ptcParams->nbits;
+		rid = ptcParams->rid;
+
+		if (saved_rid != rid) {
+			ia64_set_rr(start, (unsigned long)rid);
+			ia64_srlz_d();
+		}
+
+		sn1_ptc_l_range(start, end, nbits);
+
+		if (saved_rid != rid) 
+			ia64_set_rr(start, (unsigned long)saved_rid);
+
+		ia64_srlz_i();
+
+		result = atomic_dec(&ptcParams->unfinished_count);
+#ifdef PTCDEBUG
+		{
+		    int i = ptcParams-&ptcParamArray[0];
+		    ptcParamsResults[cpu][i] = (char) result;
+		    ptcParamsCounts[cpu][i]++;
+		}
+#endif /* PTCDEBUG */
+
+		if (++ptcParams == &ptcParamArray[NUMPTC])
+			ptcParams = &ptcParamArray[0];
+
+	} while (ptcParams != ptcParamsEmpty);
+
+	ptcParamsNextByCpu[cpu*16] = ptcParams;
+}
+
+/**
+ * sn1_global_tlb_purge - flush a translation cache range on all processors
+ * @start: start of virtual address range to flush
+ * @end: end of virtual address range
+ * @nbits: specifies number of bytes to purge per instruction (num = 1<<(nbits & 0xfc))
+ *
+ * Flushes the translation cache of all processors from @start to @end.
+ */
+void
+sn1_global_tlb_purge (unsigned long start, unsigned long end, unsigned long nbits)
+{
+	ptc_params_t	*params;
+	ptc_params_t	*next;
+	unsigned long	irqflags;
+#ifdef PTCDEBUG
+	ptc_params_t	*nextnext;
+	int		backlog = 0;
+#endif
+
+	if (smp_num_cpus == 1) {
+		sn1_ptc_l_range(start, end, nbits);
+		return;
+	}
+
+	if (in_interrupt()) {
+		/*
+		 *  If at interrupt level and cannot get spinlock, 
+		 *  then do something useful by flushing own tlbflush queue
+		 *  so as to avoid a possible deadlock.
+		 */
+		while (!spin_trylock(&ptcParamsLock)) {
+			local_irq_save(irqflags);
+			sn1_received_flush_tlb();
+			local_irq_restore(irqflags);
+			udelay(10);	/* take it easier on the bus */	
+		}
+	} else {
+		spin_lock(&ptcParamsLock);
+	}
+
+	if (!ptcInit) {
+		int cpu;
+		ptcInit = 1;
+		memset(ptcParamArray, 0, sizeof(ptcParamArray));
+		ptcParamsEmpty = &ptcParamArray[0];
+		for (cpu=0; cpu<NR_CPUS; cpu++)
+			ptcParamsNextByCpu[cpu*16] = &ptcParamArray[0];
+
+#ifdef PTCDEBUG
+		memset(ptcBacklog, 0, sizeof(ptcBacklog));
+		memset(ptcParamsCounts, 0, sizeof(ptcParamsCounts));
+		memset(ptcParamsResults, 0, sizeof(ptcParamsResults));
+#endif	/* PTCDEBUG */
+	}
+
+	params = (ptc_params_t *) ptcParamsEmpty;
+	next = (ptc_params_t *) ptcParamsEmpty + 1;
+	if (next == &ptcParamArray[NUMPTC])
+		next = &ptcParamArray[0];
+
+#ifdef PTCDEBUG
+	nextnext = next + 1;
+	if (nextnext == &ptcParamArray[NUMPTC])
+		nextnext = &ptcParamArray[0];
+
+	if (ptcCountBacklog) {
+		/* quick count of backlog */
+		ptc_params_t *ptr;
+
+		/* check the current pointer to the beginning */
+		ptr = params;
+		while(--ptr >= &ptcParamArray[0]) {
+			if (atomic_read(&ptr->unfinished_count) == 0)
+				break;
+			++backlog;
+		}
+
+		if (backlog) {
+			/* check the end of the array */
+			ptr = &ptcParamArray[NUMPTC];
+			while (--ptr > params) {
+				if (atomic_read(&ptr->unfinished_count) == 0)
+					break;
+				++backlog;
+			}
+		}
+		ptcBacklog[backlog]++;
+	}
+#endif	/* PTCDEBUG */
+
+	/* wait for the next entry to clear...should be rare */
+	if (atomic_read(&next->unfinished_count) > 0) {
+#ifdef PTCDEBUG
+		ptcParamsAllBusy++;
+
+		if (atomic_read(&nextnext->unfinished_count) == 0) {
+		    if (atomic_read(&next->unfinished_count) > 0) {
+			panic("\nnonzero next zero nextnext %lx %lx\n",
+			    (long)next, (long)nextnext);
+		    }
+		}
+#endif
+
+		/* it could be this cpu that is behind */
+		local_irq_save(irqflags);
+		sn1_received_flush_tlb();
+		local_irq_restore(irqflags);
+
+		/* now we know it's not this cpu, so just wait */
+		while (atomic_read(&next->unfinished_count) > 0) {
+			barrier();
+		}
+	}
+
+	params->start = start;
+	params->end = end;
+	params->nbits = nbits;
+	params->rid = (unsigned int) ia64_get_rr(start);
+	atomic_set(&params->unfinished_count, smp_num_cpus);
+
+	/* The atomic_set above can hit memory *after* the update
+	 * to ptcParamsEmpty below, which opens a timing window
+	 * that other cpus can squeeze into!
+	 */
+	mb();
+
+	/* everything is ready to process:
+	 *	-- global lock is held
+	 *	-- new entry + 1 is free
+	 *	-- new entry is set up
+	 * so now:
+	 *	-- update the global next pointer
+	 *	-- unlock the global lock
+	 *	-- send IPI to notify other cpus
+	 *	-- process the data ourselves
+	 */
+	ptcParamsEmpty = next;
+	spin_unlock(&ptcParamsLock);
+	smp_send_flush_tlb();
+
+	local_irq_save(irqflags);
+	sn1_received_flush_tlb();
+	local_irq_restore(irqflags);
+
+	/* Currently we don't think global TLB purges need to be atomic.
+	 * All CPUs get sent IPIs, so if they haven't done the purge,
+	 * they're busy with interrupts that are at the IPI level, which is
+	 * priority 15.  We're asserting that any code at that level
+	 * shouldn't be using user TLB entries.  To change this to wait
+	 * for all the flushes to complete, enable the following code.
+	 */
+#ifdef SN1_SYNCHRONOUS_GLOBAL_TLB_PURGE
+	/* this code is not tested */
+	/* wait for the flush to complete */
+	while (atomic_read(&params.unfinished_count) > 1)
+		barrier();
+
+	atomic_set(&params->unfinished_count, 0);
+#endif
+}
+
+/**
+ * sn_send_IPI_phys - send an IPI to a Nasid and slice
+ * @physid: physical cpuid to receive the interrupt.
+ * @vector: command to send
+ * @delivery_mode: delivery mechanism
+ *
+ * Sends an IPI (interprocessor interrupt) to the processor specified by
+ * @physid
+ *
+ * @delivery_mode can be one of the following
+ *
+ * %IA64_IPI_DM_INT - pend an interrupt
+ * %IA64_IPI_DM_PMI - pend a PMI
+ * %IA64_IPI_DM_NMI - pend an NMI
+ * %IA64_IPI_DM_INIT - pend an INIT interrupt
+ */
+void
+sn_send_IPI_phys(long physid, int vector, int delivery_mode)
+{
+	long		*p;
+	long		nasid, slice;
+
+	static int 	off[4] = {0x1800080, 0x1800088, 0x1a00080, 0x1a00088};
+
+	nasid = cpu_physical_id_to_nasid(physid);
+        slice = cpu_physical_id_to_slice(physid);
+
+	p = (long*)(0xc0000a0000000000LL | (nasid<<33) | off[slice]);
+
+#if defined(ZZZBRINGUP)
+	{
+	static int count=0;
+	if (count++ < 10) printk("ZZ sendIPI 0x%x vec %d, nasid 0x%lx, slice %ld, adr 0x%lx\n",
+		smp_processor_id(), vector, nasid, slice, (long)p);
+	}
+#endif
+	mb();
+	*p = (delivery_mode << 8) | (vector & 0xff);
+}
+
+
+/**
+ * sn1_send_IPI - send an IPI to a processor
+ * @cpuid: target of the IPI
+ * @vector: command to send
+ * @delivery_mode: delivery mechanism
+ * @redirect: redirect the IPI?
+ *
+ * Sends an IPI (interprocessor interrupt) to the processor specified by
+ * @cpuid.  @delivery_mode can be one of the following
+ *
+ * %IA64_IPI_DM_INT - pend an interrupt
+ * %IA64_IPI_DM_PMI - pend a PMI
+ * %IA64_IPI_DM_NMI - pend an NMI
+ * %IA64_IPI_DM_INIT - pend an INIT interrupt
+ */
+void
+sn1_send_IPI(int cpuid, int vector, int delivery_mode, int redirect)
+{
+	long		physid;
+
+	physid = cpu_physical_id(cpuid);
+
+	sn_send_IPI_phys(physid, vector, delivery_mode);
+}
+#ifdef CONFIG_SMP
+
+#ifdef PTC_NOTYET
+static void __init
+process_sal_ptc_domain_info(ia64_sal_ptc_domain_info_t *di, int domain)
+{
+	ia64_sal_ptc_domain_proc_entry_t	*pe;
+	int 					i, sapicid, cpuid;
+
+	pe = __va(di->proc_list);
+	for (i=0; i<di->proc_count; i++, pe++) {
+		sapicid = id_eid_to_sapicid(pe->id, pe->eid);
+		cpuid = cpu_logical_id(sapicid);
+		sn_sapicid_info[cpuid].domain = domain;
+		sn_sapicid_info[cpuid].sapicid = sapicid;
+	}
+}
+
+
+static void __init
+process_sal_desc_ptc(ia64_sal_desc_ptc_t *ptc)
+{
+	ia64_sal_ptc_domain_info_t	*di;
+	int i;
+
+	di = __va(ptc->domain_info);
+	for (i=0; i<ptc->num_domains; i++, di++) {
+		process_sal_ptc_domain_info(di, i);	
+	}
+}
+#endif /* PTC_NOTYET */
+
+/**
+ * init_sn1_smp_config - setup PTC domains per processor
+ */
+void __init
+init_sn1_smp_config(void)
+{
+	if (!ia64_ptc_domain_info)  {
+		printk("SMP: Can't find PTC domain info. Forcing UP mode\n");
+		smp_num_cpus = 1;
+		return;
+	}
+
+#ifdef PTC_NOTYET
+	memset (sn_sapicid_info, -1, sizeof(sn_sapicid_info));
+	process_sal_desc_ptc(ia64_ptc_domain_info);
+#endif
+}
+
+#else /* CONFIG_SMP */
+
+void __init
+init_sn1_smp_config(void)
+{
+
+#ifdef PTC_NOTYET
+	sn_sapicid_info[0].sapicid = hard_smp_processor_id();
+#endif
+}
+
+#endif /* CONFIG_SMP */