[PATCH] sparc: Use generic idle loop

Sam Ravnborg
2013-03-29T20:29:30Z

Add generic cpu_idle support

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

sparc64:
- smp_callin() includes cpu_startup_entry() call so we can
skip calling cpu_idle from assembler
- add arch_cpu_idle_enter() and arch_cpu_idle_dead()

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Cc: David S. Miller <davem@davemloft.net>

---
This patch is on top of smp/testing in the tip tree.
It is build tested on sparc32 + sparc64

Sam

diff --git a/arch/sparc/Kconfig b/arch/sparc/Kconfig
index 3d361f2..5f22169 100644
--- a/arch/sparc/Kconfig
+++ b/arch/sparc/Kconfig
@@ -39,6 +39,7 @@ config SPARC
select GENERIC_CLOCKEVENTS
select GENERIC_STRNCPY_FROM_USER
select GENERIC_STRNLEN_USER
+ select GENERIC_IDLE_LOOP
select MODULES_USE_ELF_RELA
select ODD_RT_SIGACTION
select OLD_SIGSUSPEND
diff --git a/arch/sparc/kernel/hvtramp.S b/arch/sparc/kernel/hvtramp.S
index 9365432..605c960 100644
--- 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 62eede1..ec92959 100644
--- a/arch/sparc/kernel/process_32.c
+++ b/arch/sparc/kernel/process_32.c
@@ -64,23 +64,13 @@ 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)
+/* the idle loop on a Sparc... ;) */
+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)();
+ else
+ cpu_relax();
}

/* 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 cdb80b2..5ed6b02 100644
--- a/arch/sparc/kernel/process_64.c
+++ b/arch/sparc/kernel/process_64.c
@@ -52,8 +52,13 @@

#include "kstack.h"

-static void sparc64_yield(int cpu)
+/* The idle loop on sparc64. */
+void arch_cpu_idle_enter()
{
+ int cpu;
+
+ cpu = smp_processor_id();
+
if (tlb_type != hypervisor) {
touch_nmi_watchdog();
return;
@@ -88,31 +93,10 @@ static void sparc64_yield(int cpu)
set_thread_flag(TIF_POLLING_NRFLAG);
}

-/* The idle loop on sparc64. */
-void cpu_idle(void)
+void arch_cpu_idle_dead()
{
- 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();
- }
+ sched_preempt_enable_no_resched();
+ cpu_play_dead();
}

#ifdef CONFIG_COMPAT
diff --git a/arch/sparc/kernel/smp_32.c b/arch/sparc/kernel/smp_32.c
index 9e7e6d7..e3f2b81 100644
--- 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 537eb66..c025ffc 100644
--- 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 da1b781..2e973a2 100644
--- 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