svn commit: r286060 - in releng/10.2/sys: kern sparc64/include sparc64/sparc64
Marius Strobl
marius at FreeBSD.org
Thu Jul 30 02:45:38 UTC 2015
Author: marius
Date: Thu Jul 30 02:45:35 2015
New Revision: 286060
URL: https://svnweb.freebsd.org/changeset/base/286060
Log:
MFC: r285839 (r286055 in stable/10)
o Revert the other functional half of r239864, i. e. the merge of r134227
from x86 to use smp_ipi_mtx spin lock not only for smp_rendezvous_cpus()
but also for the MD cache invalidation, TLB demapping and remote register
reading IPIs due to the following reasons:
- The cross-IPI SMP deadlock x86 otherwise is subject to can't happen on
sparc64. That's because on sparc64, spin locks don't disable interrupts
completely but only raise the processor interrupt level to PIL_TICK. This
means that IPIs still get delivered and direct dispatch IPIs such as the
cache invalidation etc. IPIs in question are still executed.
- In smp_rendezvous_cpus(), smp_ipi_mtx is held not only while sending an
IPI_RENDEZVOUS, but until all CPUs have processed smp_rendezvous_action().
Consequently, smp_ipi_mtx may be locked for an extended amount of time as
queued IPIs (as opposed to the direct ones) such as IPI_RENDEZVOUS are
scheduled via a soft interrupt. Moreover, given that this soft interrupt
is only delivered at PIL_RENDEZVOUS, processing of smp_rendezvous_action()
on a target may be interrupted by f. e. a tick interrupt at PIL_TICK, in
turn leading to the target in question trying to send an IPI by itself
while IPI_RENDEZVOUS isn't fully handled, yet, and, thus, resulting in a
deadlock.
o As mentioned in the commit message of r245850, on least some sun4u platforms
concurrent sending of IPIs by different CPUs is fatal. Therefore, hold the
reintroduced MD ipi_mtx also while delivering cross-traps via MI helpers,
i. e. ipi_{all_but_self,cpu,selected}().
o Akin to x86, let the last CPU to process cpu_mp_bootstrap() set smp_started
instead of the BSP in cpu_mp_unleash(). This ensures that all APs actually
are started, when smp_started is no longer 0.
o In all MD and MI IPI helpers, check for smp_started == 1 rather than for
smp_cpus > 1 or nothing at all. This avoids races during boot causing IPIs
trying to be delivered to APs that in fact aren't up and running, yet.
While at it, move setting of the cpu_ipi_{selected,single}() pointers to
the appropriate delivery functions from mp_init() to cpu_mp_start() where
it's better suited and allows to get rid of the global isjbus variable.
o Given that now concurrent IPI delivery no longer is possible, also nuke
the delays before completely disabling interrupts again in the CPU-specific
cross-trap delivery functions, previously giving other CPUs a window for
sending IPIs on their part. Actually, we now should be able to entirely get
rid of completely disabling interrupts in these functions. Such a change
needs more testing, though.
o In {s,}tick_get_timecount_mp(), make the {s,}tick variable static. While not
necessary for correctness, this avoids page faults when accessing the stack
of a foreign CPU as {s,}tick now is locked into the TLBs as part of static
kernel data. Hence, {s,}tick_get_timecount_mp() always execute as fast as
possible, avoiding jitter.
PR: 201245
Approved by: re (gjb)
Modified:
releng/10.2/sys/kern/subr_witness.c
releng/10.2/sys/sparc64/include/smp.h
releng/10.2/sys/sparc64/sparc64/machdep.c
releng/10.2/sys/sparc64/sparc64/mp_machdep.c
releng/10.2/sys/sparc64/sparc64/tick.c
Directory Properties:
releng/10.2/ (props changed)
Modified: releng/10.2/sys/kern/subr_witness.c
==============================================================================
--- releng/10.2/sys/kern/subr_witness.c Thu Jul 30 02:23:09 2015 (r286059)
+++ releng/10.2/sys/kern/subr_witness.c Thu Jul 30 02:45:35 2015 (r286060)
@@ -666,6 +666,9 @@ static struct witness_order_list_entry o
*/
{ "intrcnt", &lock_class_mtx_spin },
{ "icu", &lock_class_mtx_spin },
+#if defined(SMP) && defined(__sparc64__)
+ { "ipi", &lock_class_mtx_spin },
+#endif
#ifdef __i386__
{ "allpmaps", &lock_class_mtx_spin },
{ "descriptor tables", &lock_class_mtx_spin },
Modified: releng/10.2/sys/sparc64/include/smp.h
==============================================================================
--- releng/10.2/sys/sparc64/include/smp.h Thu Jul 30 02:23:09 2015 (r286059)
+++ releng/10.2/sys/sparc64/include/smp.h Thu Jul 30 02:45:35 2015 (r286060)
@@ -39,13 +39,15 @@
#ifndef LOCORE
+#include <sys/param.h>
#include <sys/cpuset.h>
+#include <sys/lock.h>
+#include <sys/mutex.h>
#include <sys/proc.h>
#include <sys/sched.h>
#include <sys/smp.h>
#include <machine/intr_machdep.h>
-#include <machine/pcb.h>
#include <machine/tte.h>
#define IDR_BUSY 0x0000000000000001ULL
@@ -96,6 +98,7 @@ struct ipi_tlb_args {
};
#define ita_va ita_start
+struct pcb;
struct pcpu;
extern struct pcb stoppcbs[];
@@ -108,8 +111,9 @@ extern cpu_ipi_selected_t *cpu_ipi_selec
typedef void cpu_ipi_single_t(u_int, u_long, u_long, u_long);
extern cpu_ipi_single_t *cpu_ipi_single;
-void mp_init(u_int cpu_impl);
+void mp_init(void);
+extern struct mtx ipi_mtx;
extern struct ipi_cache_args ipi_cache_args;
extern struct ipi_rd_args ipi_rd_args;
extern struct ipi_tlb_args ipi_tlb_args;
@@ -139,23 +143,37 @@ ipi_all_but_self(u_int ipi)
{
cpuset_t cpus;
+ if (__predict_false(smp_started == 0))
+ return;
cpus = all_cpus;
+ sched_pin();
CPU_CLR(PCPU_GET(cpuid), &cpus);
+ mtx_lock_spin(&ipi_mtx);
cpu_ipi_selected(cpus, 0, (u_long)tl_ipi_level, ipi);
+ mtx_unlock_spin(&ipi_mtx);
+ sched_unpin();
}
static __inline void
ipi_selected(cpuset_t cpus, u_int ipi)
{
+ if (__predict_false(smp_started == 0 || CPU_EMPTY(&cpus)))
+ return;
+ mtx_lock_spin(&ipi_mtx);
cpu_ipi_selected(cpus, 0, (u_long)tl_ipi_level, ipi);
+ mtx_unlock_spin(&ipi_mtx);
}
static __inline void
ipi_cpu(int cpu, u_int ipi)
{
+ if (__predict_false(smp_started == 0))
+ return;
+ mtx_lock_spin(&ipi_mtx);
cpu_ipi_single(cpu, 0, (u_long)tl_ipi_level, ipi);
+ mtx_unlock_spin(&ipi_mtx);
}
#if defined(_MACHINE_PMAP_H_) && defined(_SYS_MUTEX_H_)
@@ -165,11 +183,11 @@ ipi_dcache_page_inval(void *func, vm_pad
{
struct ipi_cache_args *ica;
- if (smp_cpus == 1)
+ if (__predict_false(smp_started == 0))
return (NULL);
sched_pin();
ica = &ipi_cache_args;
- mtx_lock_spin(&smp_ipi_mtx);
+ mtx_lock_spin(&ipi_mtx);
ica->ica_mask = all_cpus;
CPU_CLR(PCPU_GET(cpuid), &ica->ica_mask);
ica->ica_pa = pa;
@@ -182,11 +200,11 @@ ipi_icache_page_inval(void *func, vm_pad
{
struct ipi_cache_args *ica;
- if (smp_cpus == 1)
+ if (__predict_false(smp_started == 0))
return (NULL);
sched_pin();
ica = &ipi_cache_args;
- mtx_lock_spin(&smp_ipi_mtx);
+ mtx_lock_spin(&ipi_mtx);
ica->ica_mask = all_cpus;
CPU_CLR(PCPU_GET(cpuid), &ica->ica_mask);
ica->ica_pa = pa;
@@ -199,11 +217,11 @@ ipi_rd(u_int cpu, void *func, u_long *va
{
struct ipi_rd_args *ira;
- if (smp_cpus == 1)
+ if (__predict_false(smp_started == 0))
return (NULL);
sched_pin();
ira = &ipi_rd_args;
- mtx_lock_spin(&smp_ipi_mtx);
+ mtx_lock_spin(&ipi_mtx);
CPU_SETOF(cpu, &ira->ira_mask);
ira->ira_val = val;
cpu_ipi_single(cpu, 0, (u_long)func, (u_long)ira);
@@ -216,7 +234,7 @@ ipi_tlb_context_demap(struct pmap *pm)
struct ipi_tlb_args *ita;
cpuset_t cpus;
- if (smp_cpus == 1)
+ if (__predict_false(smp_started == 0))
return (NULL);
sched_pin();
cpus = pm->pm_active;
@@ -227,7 +245,7 @@ ipi_tlb_context_demap(struct pmap *pm)
return (NULL);
}
ita = &ipi_tlb_args;
- mtx_lock_spin(&smp_ipi_mtx);
+ mtx_lock_spin(&ipi_mtx);
ita->ita_mask = cpus;
ita->ita_pmap = pm;
cpu_ipi_selected(cpus, 0, (u_long)tl_ipi_tlb_context_demap,
@@ -241,7 +259,7 @@ ipi_tlb_page_demap(struct pmap *pm, vm_o
struct ipi_tlb_args *ita;
cpuset_t cpus;
- if (smp_cpus == 1)
+ if (__predict_false(smp_started == 0))
return (NULL);
sched_pin();
cpus = pm->pm_active;
@@ -252,7 +270,7 @@ ipi_tlb_page_demap(struct pmap *pm, vm_o
return (NULL);
}
ita = &ipi_tlb_args;
- mtx_lock_spin(&smp_ipi_mtx);
+ mtx_lock_spin(&ipi_mtx);
ita->ita_mask = cpus;
ita->ita_pmap = pm;
ita->ita_va = va;
@@ -266,7 +284,7 @@ ipi_tlb_range_demap(struct pmap *pm, vm_
struct ipi_tlb_args *ita;
cpuset_t cpus;
- if (smp_cpus == 1)
+ if (__predict_false(smp_started == 0))
return (NULL);
sched_pin();
cpus = pm->pm_active;
@@ -277,7 +295,7 @@ ipi_tlb_range_demap(struct pmap *pm, vm_
return (NULL);
}
ita = &ipi_tlb_args;
- mtx_lock_spin(&smp_ipi_mtx);
+ mtx_lock_spin(&ipi_mtx);
ita->ita_mask = cpus;
ita->ita_pmap = pm;
ita->ita_start = start;
@@ -292,10 +310,10 @@ ipi_wait(void *cookie)
{
volatile cpuset_t *mask;
- if ((mask = cookie) != NULL) {
+ if (__predict_false((mask = cookie) != NULL)) {
while (!CPU_EMPTY(mask))
;
- mtx_unlock_spin(&smp_ipi_mtx);
+ mtx_unlock_spin(&ipi_mtx);
sched_unpin();
}
}
Modified: releng/10.2/sys/sparc64/sparc64/machdep.c
==============================================================================
--- releng/10.2/sys/sparc64/sparc64/machdep.c Thu Jul 30 02:23:09 2015 (r286059)
+++ releng/10.2/sys/sparc64/sparc64/machdep.c Thu Jul 30 02:45:35 2015 (r286060)
@@ -503,7 +503,7 @@ sparc64_init(caddr_t mdp, u_long o1, u_l
}
#ifdef SMP
- mp_init(cpu_impl);
+ mp_init();
#endif
/*
Modified: releng/10.2/sys/sparc64/sparc64/mp_machdep.c
==============================================================================
--- releng/10.2/sys/sparc64/sparc64/mp_machdep.c Thu Jul 30 02:23:09 2015 (r286059)
+++ releng/10.2/sys/sparc64/sparc64/mp_machdep.c Thu Jul 30 02:45:35 2015 (r286060)
@@ -82,6 +82,7 @@ __FBSDID("$FreeBSD$");
#include <machine/atomic.h>
#include <machine/bus.h>
#include <machine/cpu.h>
+#include <machine/cpufunc.h>
#include <machine/md_var.h>
#include <machine/metadata.h>
#include <machine/ofw_machdep.h>
@@ -113,12 +114,13 @@ struct ipi_rd_args ipi_rd_args;
struct ipi_tlb_args ipi_tlb_args;
struct pcb stoppcbs[MAXCPU];
+struct mtx ipi_mtx;
+
cpu_ipi_selected_t *cpu_ipi_selected;
cpu_ipi_single_t *cpu_ipi_single;
static vm_offset_t mp_tramp;
static u_int cpuid_to_mid[MAXCPU];
-static int isjbus;
static volatile cpuset_t shutdown_cpus;
static void ap_count(phandle_t node, u_int mid, u_int cpu_impl);
@@ -138,7 +140,7 @@ static cpu_ipi_single_t spitfire_ipi_sin
SYSINIT(cpu_mp_unleash, SI_SUB_SMP, SI_ORDER_FIRST, cpu_mp_unleash, NULL);
void
-mp_init(u_int cpu_impl)
+mp_init(void)
{
struct tte *tp;
int i;
@@ -157,24 +159,6 @@ mp_init(u_int cpu_impl)
}
for (i = 0; i < PAGE_SIZE; i += sizeof(vm_offset_t))
flush(mp_tramp + i);
-
- /*
- * On UP systems cpu_ipi_selected() can be called while
- * cpu_mp_start() wasn't so initialize these here.
- */
- if (cpu_impl == CPU_IMPL_ULTRASPARCIIIi ||
- cpu_impl == CPU_IMPL_ULTRASPARCIIIip) {
- isjbus = 1;
- cpu_ipi_selected = jalapeno_ipi_selected;
- cpu_ipi_single = jalapeno_ipi_single;
- } else if (cpu_impl == CPU_IMPL_SPARC64V ||
- cpu_impl >= CPU_IMPL_ULTRASPARCIII) {
- cpu_ipi_selected = cheetah_ipi_selected;
- cpu_ipi_single = cheetah_ipi_single;
- } else {
- cpu_ipi_selected = spitfire_ipi_selected;
- cpu_ipi_single = spitfire_ipi_single;
- }
}
static void
@@ -219,7 +203,7 @@ foreach_ap(phandle_t node, void (*func)(
* Probe for other CPUs.
*/
void
-cpu_mp_setmaxid()
+cpu_mp_setmaxid(void)
{
CPU_SETOF(curcpu, &all_cpus);
@@ -277,6 +261,25 @@ sun4u_startcpu(phandle_t cpu, void *func
void
cpu_mp_start(void)
{
+ u_int cpu_impl, isjbus;
+
+ mtx_init(&ipi_mtx, "ipi", NULL, MTX_SPIN);
+
+ isjbus = 0;
+ cpu_impl = PCPU_GET(impl);
+ if (cpu_impl == CPU_IMPL_ULTRASPARCIIIi ||
+ cpu_impl == CPU_IMPL_ULTRASPARCIIIip) {
+ isjbus = 1;
+ cpu_ipi_selected = jalapeno_ipi_selected;
+ cpu_ipi_single = jalapeno_ipi_single;
+ } else if (cpu_impl == CPU_IMPL_SPARC64V ||
+ cpu_impl >= CPU_IMPL_ULTRASPARCIII) {
+ cpu_ipi_selected = cheetah_ipi_selected;
+ cpu_ipi_single = cheetah_ipi_single;
+ } else {
+ cpu_ipi_selected = spitfire_ipi_selected;
+ cpu_ipi_single = spitfire_ipi_single;
+ }
intr_setup(PIL_AST, cpu_ipi_ast, -1, NULL, NULL);
intr_setup(PIL_RENDEZVOUS, (ih_func_t *)smp_rendezvous_action,
@@ -360,7 +363,7 @@ cpu_mp_announce(void)
}
static void
-cpu_mp_unleash(void *v)
+cpu_mp_unleash(void *v __unused)
{
volatile struct cpu_start_args *csa;
struct pcpu *pc;
@@ -407,7 +410,6 @@ cpu_mp_unleash(void *v)
membar(StoreLoad);
csa->csa_count = 0;
- smp_started = 1;
}
void
@@ -464,6 +466,9 @@ cpu_mp_bootstrap(struct pcpu *pc)
while (csa->csa_count != 0)
;
+ if (smp_cpus == mp_ncpus)
+ atomic_store_rel_int(&smp_started, 1);
+
/* Start per-CPU event timers. */
cpu_initclocks_ap();
@@ -530,7 +535,7 @@ cpu_ipi_stop(struct trapframe *tf __unus
}
static void
-cpu_ipi_preempt(struct trapframe *tf)
+cpu_ipi_preempt(struct trapframe *tf __unused)
{
sched_preempt(curthread);
@@ -573,9 +578,11 @@ spitfire_ipi_single(u_int cpu, u_long d0
u_int mid;
int i;
+ mtx_assert(&ipi_mtx, MA_OWNED);
KASSERT(cpu != curcpu, ("%s: CPU can't IPI itself", __func__));
KASSERT((ldxa(0, ASI_INTR_DISPATCH_STATUS) & IDR_BUSY) == 0,
("%s: outstanding dispatch", __func__));
+
mid = cpuid_to_mid[cpu];
for (i = 0; i < IPI_RETRIES; i++) {
s = intr_disable();
@@ -601,12 +608,6 @@ spitfire_ipi_single(u_int cpu, u_long d0
intr_restore(s);
if ((ids & (IDR_BUSY | IDR_NACK)) == 0)
return;
- /*
- * Leave interrupts enabled for a bit before retrying
- * in order to avoid deadlocks if the other CPU is also
- * trying to send an IPI.
- */
- DELAY(2);
}
if (kdb_active != 0 || panicstr != NULL)
printf("%s: couldn't send IPI to module 0x%u\n",
@@ -624,10 +625,12 @@ cheetah_ipi_single(u_int cpu, u_long d0,
u_int mid;
int i;
+ mtx_assert(&ipi_mtx, MA_OWNED);
KASSERT(cpu != curcpu, ("%s: CPU can't IPI itself", __func__));
KASSERT((ldxa(0, ASI_INTR_DISPATCH_STATUS) &
IDR_CHEETAH_ALL_BUSY) == 0,
("%s: outstanding dispatch", __func__));
+
mid = cpuid_to_mid[cpu];
for (i = 0; i < IPI_RETRIES; i++) {
s = intr_disable();
@@ -644,12 +647,6 @@ cheetah_ipi_single(u_int cpu, u_long d0,
intr_restore(s);
if ((ids & (IDR_BUSY | IDR_NACK)) == 0)
return;
- /*
- * Leave interrupts enabled for a bit before retrying
- * in order to avoid deadlocks if the other CPU is also
- * trying to send an IPI.
- */
- DELAY(2);
}
if (kdb_active != 0 || panicstr != NULL)
printf("%s: couldn't send IPI to module 0x%u\n",
@@ -669,13 +666,14 @@ cheetah_ipi_selected(cpuset_t cpus, u_lo
u_int cpu;
int i;
+ mtx_assert(&ipi_mtx, MA_OWNED);
+ KASSERT(!CPU_EMPTY(&cpus), ("%s: no CPUs to IPI", __func__));
KASSERT(!CPU_ISSET(curcpu, &cpus), ("%s: CPU can't IPI itself",
__func__));
KASSERT((ldxa(0, ASI_INTR_DISPATCH_STATUS) &
IDR_CHEETAH_ALL_BUSY) == 0,
("%s: outstanding dispatch", __func__));
- if (CPU_EMPTY(&cpus))
- return;
+
ids = 0;
for (i = 0; i < IPI_RETRIES * mp_ncpus; i++) {
s = intr_disable();
@@ -709,12 +707,6 @@ cheetah_ipi_selected(cpuset_t cpus, u_lo
}
if (CPU_EMPTY(&cpus))
return;
- /*
- * Leave interrupts enabled for a bit before retrying
- * in order to avoid deadlocks if the other CPUs are
- * also trying to send IPIs.
- */
- DELAY(2 * mp_ncpus);
}
if (kdb_active != 0 || panicstr != NULL)
printf("%s: couldn't send IPI (cpus=%s ids=0x%lu)\n",
@@ -732,10 +724,12 @@ jalapeno_ipi_single(u_int cpu, u_long d0
u_int busy, busynack, mid;
int i;
+ mtx_assert(&ipi_mtx, MA_OWNED);
KASSERT(cpu != curcpu, ("%s: CPU can't IPI itself", __func__));
KASSERT((ldxa(0, ASI_INTR_DISPATCH_STATUS) &
IDR_CHEETAH_ALL_BUSY) == 0,
("%s: outstanding dispatch", __func__));
+
mid = cpuid_to_mid[cpu];
busy = IDR_BUSY << (2 * mid);
busynack = (IDR_BUSY | IDR_NACK) << (2 * mid);
@@ -754,12 +748,6 @@ jalapeno_ipi_single(u_int cpu, u_long d0
intr_restore(s);
if ((ids & busynack) == 0)
return;
- /*
- * Leave interrupts enabled for a bit before retrying
- * in order to avoid deadlocks if the other CPU is also
- * trying to send an IPI.
- */
- DELAY(2);
}
if (kdb_active != 0 || panicstr != NULL)
printf("%s: couldn't send IPI to module 0x%u\n",
@@ -778,13 +766,14 @@ jalapeno_ipi_selected(cpuset_t cpus, u_l
u_int cpu;
int i;
+ mtx_assert(&ipi_mtx, MA_OWNED);
+ KASSERT(!CPU_EMPTY(&cpus), ("%s: no CPUs to IPI", __func__));
KASSERT(!CPU_ISSET(curcpu, &cpus), ("%s: CPU can't IPI itself",
__func__));
KASSERT((ldxa(0, ASI_INTR_DISPATCH_STATUS) &
IDR_CHEETAH_ALL_BUSY) == 0,
("%s: outstanding dispatch", __func__));
- if (CPU_EMPTY(&cpus))
- return;
+
ids = 0;
for (i = 0; i < IPI_RETRIES * mp_ncpus; i++) {
s = intr_disable();
@@ -811,12 +800,6 @@ jalapeno_ipi_selected(cpuset_t cpus, u_l
if ((ids & (IDR_NACK <<
(2 * cpuid_to_mid[cpu]))) == 0)
CPU_CLR(cpu, &cpus);
- /*
- * Leave interrupts enabled for a bit before retrying
- * in order to avoid deadlocks if the other CPUs are
- * also trying to send IPIs.
- */
- DELAY(2 * mp_ncpus);
}
if (kdb_active != 0 || panicstr != NULL)
printf("%s: couldn't send IPI (cpus=%s ids=0x%lu)\n",
Modified: releng/10.2/sys/sparc64/sparc64/tick.c
==============================================================================
--- releng/10.2/sys/sparc64/sparc64/tick.c Thu Jul 30 02:23:09 2015 (r286059)
+++ releng/10.2/sys/sparc64/sparc64/tick.c Thu Jul 30 02:45:35 2015 (r286060)
@@ -31,8 +31,6 @@ __FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
-#include <sys/lock.h>
-#include <sys/mutex.h>
#include <sys/pcpu.h>
#include <sys/proc.h>
#include <sys/sched.h>
@@ -46,7 +44,6 @@ __FBSDID("$FreeBSD$");
#include <vm/vm.h>
#include <vm/pmap.h>
-#include <machine/cpu.h>
#include <machine/frame.h>
#include <machine/intr_machdep.h>
#include <machine/smp.h>
@@ -326,7 +323,7 @@ tick_get_timecount_up(struct timecounter
static u_int
stick_get_timecount_mp(struct timecounter *tc)
{
- u_long stick;
+ static u_long stick;
sched_pin();
if (curcpu == 0)
@@ -340,7 +337,7 @@ stick_get_timecount_mp(struct timecounte
static u_int
tick_get_timecount_mp(struct timecounter *tc)
{
- u_long tick;
+ static u_long tick;
sched_pin();
if (curcpu == 0)
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