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Commit 30c91d57 authored by David S. Miller's avatar David S. Miller
Browse files

[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: default avatarDavid S. Miller <davem@davemloft.net>
parent 689126a4

arch/sparc64/kernel/process.c

+32 −49
Original line number Diff line number Diff line
@@ -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));

	}



#else

	set_thread_flag(TIF_POLLING_NRFLAG);

}



/*

 * 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);