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[SPARC64]: Use sun4v_cpu_idle() in cpu_idle() on SUN4V. 

We have to turn off the "polling nrflag" bit when we sleep
the cpu like this, so that we'll get a cross-cpu interrupt
to wake the processor up from the yield.

We also have to disable PSTATE_IE in %pstate around the yield
call and recheck need_resched() in order to avoid any races.

Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
David S. Miller 2006-02-21 16:55:23 -08:00
parent 689126a48a
commit 30c91d576e
1 changed files with 28 additions and 45 deletions
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73
arch/sparc64/kernel/process.c
View File

@ -46,62 +46,47 @@
#include <asm/cpudata.h>
#include <asm/mmu_context.h>
#include <asm/unistd.h>
#include <asm/hypervisor.h>
/* #define VERBOSE_SHOWREGS */
/*
* Nothing special yet...
*/
void default_idle(void)
static void sparc64_yield(void)
{
}
if (tlb_type != hypervisor)
return;
clear_thread_flag(TIF_POLLING_NRFLAG);
smp_mb__after_clear_bit();
while (!need_resched()) {
unsigned long pstate;
#ifndef CONFIG_SMP
/* Disable interrupts. */
__asm__ __volatile__(
"rdpr %%pstate, %0\n\t"
"andn %0, %1, %0\n\t"
"wrpr %0, %%g0, %%pstate"
: "=&r" (pstate)
: "i" (PSTATE_IE));
/*
* the idle loop on a Sparc... ;)
*/
void cpu_idle(void)
{
/* endless idle loop with no priority at all */
for (;;) {
/* If current->work.need_resched is zero we should really
* setup for a system wakup event and execute a shutdown
* instruction.
*
* But this requires writing back the contents of the
* L2 cache etc. so implement this later. -DaveM
*/
while (!need_resched())
barrier();
if (!need_resched())
sun4v_cpu_yield();
preempt_enable_no_resched();
schedule();
preempt_disable();
check_pgt_cache();
/* Re-enable interrupts. */
__asm__ __volatile__(
"rdpr %%pstate, %0\n\t"
"or %0, %1, %0\n\t"
"wrpr %0, %%g0, %%pstate"
: "=&r" (pstate)
: "i" (PSTATE_IE));
}
set_thread_flag(TIF_POLLING_NRFLAG);
}
#else
/*
* the idle loop on a UltraMultiPenguin...
*
* TIF_POLLING_NRFLAG is set because we do not sleep the cpu
* inside of the idler task, so an interrupt is not needed
* to get a clean fast response.
*
* XXX Reverify this assumption... -DaveM
*
* Addendum: We do want it to do something for the signal
* delivery case, we detect that by just seeing
* if we are trying to send this to an idler or not.
*/
/* The idle loop on sparc64. */
void cpu_idle(void)
{
cpuinfo_sparc *cpuinfo = &local_cpu_data();
set_thread_flag(TIF_POLLING_NRFLAG);
while(1) {
@ -109,13 +94,11 @@ void cpu_idle(void)
preempt_enable_no_resched();
schedule();
preempt_disable();
check_pgt_cache();
}
sparc64_yield();
}
}
#endif
extern char reboot_command [];
extern void (*prom_palette)(int);