From 30c91d576e9ea41c963e7f28643219bda73b0ddc Mon Sep 17 00:00:00 2001 From: "David S. Miller" Date: Tue, 21 Feb 2006 16:55:23 -0800 Subject: [PATCH] [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 --- arch/sparc64/kernel/process.c | 81 ++++++++++++++--------------------- 1 file changed, 32 insertions(+), 49 deletions(-) diff --git a/arch/sparc64/kernel/process.c b/arch/sparc64/kernel/process.c index 1ab8283efc4c..1c7ca2f712d9 100644 --- a/arch/sparc64/kernel/process.c +++ b/arch/sparc64/kernel/process.c @@ -46,62 +46,47 @@ #include #include #include +#include /* #define VERBOSE_SHOWREGS */ -/* - * Nothing special yet... - */ -void default_idle(void) -{ -} - - - -#ifndef CONFIG_SMP - -/* - * the idle loop on a Sparc... ;) - */ -void cpu_idle(void) +static void sparc64_yield(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 (tlb_type != hypervisor) + return; - preempt_enable_no_resched(); - schedule(); - preempt_disable(); - check_pgt_cache(); + clear_thread_flag(TIF_POLLING_NRFLAG); + smp_mb__after_clear_bit(); + + while (!need_resched()) { + unsigned long pstate; + + /* Disable interrupts. */ + __asm__ __volatile__( + "rdpr %%pstate, %0\n\t" + "andn %0, %1, %0\n\t" + "wrpr %0, %%g0, %%pstate" + : "=&r" (pstate) + : "i" (PSTATE_IE)); + + if (!need_resched()) + sun4v_cpu_yield(); + + /* 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); -- 2.30.2