svn commit: r245850 - in head/sys/sparc64: include sparc64
Marius Strobl
marius at FreeBSD.org
Wed Jan 23 22:52:21 UTC 2013
Author: marius
Date: Wed Jan 23 22:52:20 2013
New Revision: 245850
URL: http://svnweb.freebsd.org/changeset/base/245850
Log:
Revert the part of r239864 which removed obtaining the SMP mutex around
reading registers from other CPUs. As it turns out, the hardware doesn't
really like concurrent IPI'ing causing adverse effects. Also the thought
deadlock when using this spin lock here and the targeted CPU(s) are also
holding or in case of nested locks can't actually happen. This is due to
the fact that on sparc64, spinlock_enter() only raises the PIL but doesn't
disable interrupts completely. Thus direct cross calls as used for the
register reading (and all other MD IPI needs) still will be executed by
the targeted CPU(s) in that case.
MFC after: 3 days
Modified:
head/sys/sparc64/include/smp.h
head/sys/sparc64/sparc64/tick.c
Modified: head/sys/sparc64/include/smp.h
==============================================================================
--- head/sys/sparc64/include/smp.h Wed Jan 23 21:44:48 2013 (r245849)
+++ head/sys/sparc64/include/smp.h Wed Jan 23 22:52:20 2013 (r245850)
@@ -42,6 +42,7 @@
#include <sys/cpuset.h>
#include <sys/proc.h>
#include <sys/sched.h>
+#include <sys/smp.h>
#include <machine/intr_machdep.h>
#include <machine/pcb.h>
@@ -202,6 +203,7 @@ ipi_rd(u_int cpu, void *func, u_long *va
return (NULL);
sched_pin();
ira = &ipi_rd_args;
+ mtx_lock_spin(&smp_ipi_mtx);
CPU_SETOF(cpu, &ira->ira_mask);
ira->ira_val = val;
cpu_ipi_single(cpu, 0, (u_long)func, (u_long)ira);
@@ -298,18 +300,6 @@ ipi_wait(void *cookie)
}
}
-static __inline void
-ipi_wait_unlocked(void *cookie)
-{
- volatile cpuset_t *mask;
-
- if ((mask = cookie) != NULL) {
- while (!CPU_EMPTY(mask))
- ;
- sched_unpin();
- }
-}
-
#endif /* _MACHINE_PMAP_H_ && _SYS_MUTEX_H_ */
#endif /* !LOCORE */
@@ -368,12 +358,6 @@ ipi_wait(void *cookie __unused)
}
static __inline void
-ipi_wait_unlocked(void *cookie __unused)
-{
-
-}
-
-static __inline void
tl_ipi_cheetah_dcache_page_inval(void)
{
Modified: head/sys/sparc64/sparc64/tick.c
==============================================================================
--- head/sys/sparc64/sparc64/tick.c Wed Jan 23 21:44:48 2013 (r245849)
+++ head/sys/sparc64/sparc64/tick.c Wed Jan 23 22:52:20 2013 (r245850)
@@ -334,7 +334,7 @@ stick_get_timecount_mp(struct timecounte
if (curcpu == 0)
stick = rdstick();
else
- ipi_wait_unlocked(ipi_rd(0, tl_ipi_stick_rd, &stick));
+ ipi_wait(ipi_rd(0, tl_ipi_stick_rd, &stick));
sched_unpin();
return (stick);
}
@@ -348,7 +348,7 @@ tick_get_timecount_mp(struct timecounter
if (curcpu == 0)
tick = rd(tick);
else
- ipi_wait_unlocked(ipi_rd(0, tl_ipi_tick_rd, &tick));
+ ipi_wait(ipi_rd(0, tl_ipi_tick_rd, &tick));
sched_unpin();
return (tick);
}
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