sparc: Use generic idle loop

Add generic cpu_idle support

sparc32:
- replace call to cpu_idle() with cpu_startup_entry()
- add arch_cpu_idle()

sparc64:
- smp_callin() now include cpu_startup_entry() call so we can
  skip calling cpu_idle from assembler
- add arch_cpu_idle() and arch_cpu_idle_dead()

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Reviewed-by: "Srivatsa S. Bhat" <srivatsa.bhat@linux.vnet.ibm.com>
Cc: torvalds@linux-foundation.org
Cc: rusty@rustcorp.com.au
Cc: paulmck@linux.vnet.ibm.com
Cc: peterz@infradead.org
Cc: magnus.damm@gmail.com
Acked-by: David Miller <davem@davemloft.net>
Link: http://lkml.kernel.org/r/20130411193850.GA2330@merkur.ravnborg.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

diff --git a/arch/sparc/Kconfig b/arch/sparc/Kconfig
index 3d361f236308c13cde14286379ec418af3e52990..ee5eacc5a6499c8d3cf856ca6ae02307ebbf69a2 100644 (file)
--- a/arch/sparc/Kconfig
+++ b/arch/sparc/Kconfig
@@ -37,6 +37,7 @@ config SPARC
        select GENERIC_SMP_IDLE_THREAD
        select GENERIC_CMOS_UPDATE
        select GENERIC_CLOCKEVENTS
+       select GENERIC_IDLE_LOOP
        select GENERIC_STRNCPY_FROM_USER
        select GENERIC_STRNLEN_USER
        select MODULES_USE_ELF_RELA

diff --git a/arch/sparc/kernel/hvtramp.S b/arch/sparc/kernel/hvtramp.S
index 9365432904d64eb7ef017506991eab7bcbea4f2f..605c960b2fa642df6030c7f3a1b9ae12bc6f1eba 100644 (file)
--- a/arch/sparc/kernel/hvtramp.S
+++ b/arch/sparc/kernel/hvtramp.S
@@ -128,8 +128,7 @@ hv_cpu_startup:
 
        call            smp_callin
         nop
-       call            cpu_idle
-        mov            0, %o0
+
        call            cpu_panic
         nop
 

diff --git a/arch/sparc/kernel/process_32.c b/arch/sparc/kernel/process_32.c
index 62eede13831a2685694986165c5ac11a36daceda..c85241006e32853a0cb71e768a99506aa2b9e246 100644 (file)
--- a/arch/sparc/kernel/process_32.c
+++ b/arch/sparc/kernel/process_32.c
@@ -64,23 +64,12 @@ extern void fpsave(unsigned long *, unsigned long *, void *, unsigned long *);
 struct task_struct *last_task_used_math = NULL;
 struct thread_info *current_set[NR_CPUS];
 
-/*
- * the idle loop on a Sparc... ;)
- */
-void cpu_idle(void)
+/* Idle loop support. */
+void arch_cpu_idle(void)
 {
-       set_thread_flag(TIF_POLLING_NRFLAG);
-
-       /* endless idle loop with no priority at all */
-       for (;;) {
-               while (!need_resched()) {
-                       if (sparc_idle)
-                               (*sparc_idle)();
-                       else
-                               cpu_relax();
-               }
-               schedule_preempt_disabled();
-       }
+       if (sparc_idle)
+               (*sparc_idle)();
+       local_irq_enable();
 }
 
 /* XXX cli/sti -> local_irq_xxx here, check this works once SMP is fixed. */

diff --git a/arch/sparc/kernel/process_64.c b/arch/sparc/kernel/process_64.c
index cdb80b2adbe0f7a02068e073480fb14e6211b8ae..9fbf0d14a361e3a8e4702b01eb0c09492168fc55 100644 (file)
--- a/arch/sparc/kernel/process_64.c
+++ b/arch/sparc/kernel/process_64.c
@@ -52,20 +52,17 @@
 
 #include "kstack.h"
 
-static void sparc64_yield(int cpu)
+/* Idle loop support on sparc64. */
+void arch_cpu_idle(void)
 {
        if (tlb_type != hypervisor) {
                touch_nmi_watchdog();
-               return;
-       }
-
-       clear_thread_flag(TIF_POLLING_NRFLAG);
-       smp_mb__after_clear_bit();
-
-       while (!need_resched() && !cpu_is_offline(cpu)) {
+       } else {
                unsigned long pstate;
 
-               /* Disable interrupts. */
+                /* The sun4v sleeping code requires that we have PSTATE.IE cleared over
+                 * the cpu sleep hypervisor call.
+                 */
                __asm__ __volatile__(
                        "rdpr %%pstate, %0\n\t"
                        "andn %0, %1, %0\n\t"
@@ -73,7 +70,7 @@ static void sparc64_yield(int cpu)
                        : "=&r" (pstate)
                        : "i" (PSTATE_IE));
 
-               if (!need_resched() && !cpu_is_offline(cpu))
+               if (!need_resched() && !cpu_is_offline(smp_processor_id()))
                        sun4v_cpu_yield();
 
                /* Re-enable interrupts. */
@@ -84,36 +81,16 @@ static void sparc64_yield(int cpu)
                        : "=&r" (pstate)
                        : "i" (PSTATE_IE));
        }
-
-       set_thread_flag(TIF_POLLING_NRFLAG);
+       local_irq_enable();
 }
 
-/* The idle loop on sparc64. */
-void cpu_idle(void)
-{
-       int cpu = smp_processor_id();
-
-       set_thread_flag(TIF_POLLING_NRFLAG);
-
-       while(1) {
-               tick_nohz_idle_enter();
-               rcu_idle_enter();
-
-               while (!need_resched() && !cpu_is_offline(cpu))
-                       sparc64_yield(cpu);
-
-               rcu_idle_exit();
-               tick_nohz_idle_exit();
-
 #ifdef CONFIG_HOTPLUG_CPU
-               if (cpu_is_offline(cpu)) {
-                       sched_preempt_enable_no_resched();
-                       cpu_play_dead();
-               }
-#endif
-               schedule_preempt_disabled();
-       }
+void arch_cpu_idle_dead()
+{
+       sched_preempt_enable_no_resched();
+       cpu_play_dead();
 }
+#endif
 
 #ifdef CONFIG_COMPAT
 static void show_regwindow32(struct pt_regs *regs)

diff --git a/arch/sparc/kernel/smp_32.c b/arch/sparc/kernel/smp_32.c
index 9e7e6d718367b18ddc2fe1c354e7509c6c524384..e3f2b81c23f14cfd9513b01b0b4c7365e61d9d77 100644 (file)
--- a/arch/sparc/kernel/smp_32.c
+++ b/arch/sparc/kernel/smp_32.c
@@ -369,7 +369,7 @@ void __cpuinit sparc_start_secondary(void *arg)
        local_irq_enable();
 
        wmb();
-       cpu_idle();
+       cpu_startup_entry(CPUHP_ONLINE);
 
        /* We should never reach here! */
        BUG();

diff --git a/arch/sparc/kernel/smp_64.c b/arch/sparc/kernel/smp_64.c
index 537eb66abd0654054aef7402ffaf857ad3971a85..c025ffce7a406a5237a9e465d2f325686db4a7d8 100644 (file)
--- a/arch/sparc/kernel/smp_64.c
+++ b/arch/sparc/kernel/smp_64.c
@@ -127,6 +127,8 @@ void __cpuinit smp_callin(void)
 
        /* idle thread is expected to have preempt disabled */
        preempt_disable();
+
+       cpu_startup_entry(CPUHP_ONLINE);
 }
 
 void cpu_panic(void)

diff --git a/arch/sparc/kernel/trampoline_64.S b/arch/sparc/kernel/trampoline_64.S
index da1b781b5e65bd8f84d210f7bdb2e9d00022ae5c..2e973a26fbda9cd9ddbc2c30017fc316eb691af4 100644 (file)
--- a/arch/sparc/kernel/trampoline_64.S
+++ b/arch/sparc/kernel/trampoline_64.S
@@ -407,8 +407,7 @@ after_lock_tlb:
 
        call            smp_callin
         nop
-       call            cpu_idle
-        mov            0, %o0
+
        call            cpu_panic
         nop
 1:     b,a,pt          %xcc, 1b