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Disable using wait in cpu_idle() until a better solution to timer and

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interrupt handling can be implemented.
This commit is contained in:
adrian 2011-10-01 05:56:25 +00:00
parent e7b8707889
commit 373e645211
1 changed files with 16 additions and 0 deletions
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16
sys/mips/mips/machdep.c
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@ -485,9 +485,24 @@ spinlock_exit(void)
/*
* call platform specific code to halt (until next interrupt) for the idle loop
*/
/*
* This is disabled because of three issues:
*
* + By calling critical_enter(), any interrupt which occurs after that but
* before the wait instruction will be handled but not serviced (in the case
* of a netisr) because preemption is not allowed at this point;
* + Any fast interrupt handler which schedules an immediate or fast callout
* will not occur until the wait instruction is interrupted, as the clock
* has already been set by cpu_idleclock();
* + There is currently no known way to atomically enable interrupts and call
* wait, which is how the i386/amd64 code gets around (1). Thus even if
* interrupts were disabled and reenabled just before the wait call, any
* interrupt that did occur may not interrupt wait.
*/
void
cpu_idle(int busy)
{
#if 0
KASSERT((mips_rd_status() & MIPS_SR_INT_IE) != 0,
("interrupts disabled in idle process."));
KASSERT((mips_rd_status() & MIPS_INT_MASK) != 0,
@ -502,6 +517,7 @@ cpu_idle(int busy)
cpu_activeclock();
critical_exit();
}
#endif
}
int