[PATCH] x86: Merge x86_32 and x86_64 cpu_idle()

[PATCH] x86: Merge x86_32 and x86_64 cpu_idle()

[Richard Weinberger]

Both functions are mostly identical, so we can merge them.

Signed-off-by: Richard Weinberger <richard@nod.at>
---
 arch/x86/include/asm/idle.h  |    1 +
 arch/x86/kernel/process.c    |  114 ++++++++++++++++++++++++++++++++++++++++++
 arch/x86/kernel/process_32.c |   60 ----------------------
 arch/x86/kernel/process_64.c |  109 ----------------------------------------
 4 files changed, 115 insertions(+), 169 deletions(-)

diff --git a/arch/x86/include/asm/idle.h b/arch/x86/include/asm/idle.h
index f49253d7..c5d1785 100644
--- a/arch/x86/include/asm/idle.h
+++ b/arch/x86/include/asm/idle.h
@@ -14,6 +14,7 @@ void exit_idle(void);
 #else /* !CONFIG_X86_64 */
 static inline void enter_idle(void) { }
 static inline void exit_idle(void) { }
+static inline void __exit_idle(void) { }
 #endif /* CONFIG_X86_64 */
 
 void amd_e400_remove_cpu(int cpu);
diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
index 15763af..6d32f9f 100644
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -12,6 +12,9 @@
 #include <linux/user-return-notifier.h>
 #include <linux/dmi.h>
 #include <linux/utsname.h>
+#include <linux/stackprotector.h>
+#include <linux/tick.h>
+#include <linux/cpuidle.h>
 #include <trace/events/power.h>
 #include <linux/hw_breakpoint.h>
 #include <asm/cpu.h>
@@ -22,6 +25,24 @@
 #include <asm/uaccess.h>
 #include <asm/i387.h>
 #include <asm/debugreg.h>
+#include <asm/nmi.h>
+
+#ifdef CONFIG_X86_64
+static DEFINE_PER_CPU(unsigned char, is_idle);
+static ATOMIC_NOTIFIER_HEAD(idle_notifier);
+
+void idle_notifier_register(struct notifier_block *n)
+{
+	atomic_notifier_chain_register(&idle_notifier, n);
+}
+EXPORT_SYMBOL_GPL(idle_notifier_register);
+
+void idle_notifier_unregister(struct notifier_block *n)
+{
+	atomic_notifier_chain_unregister(&idle_notifier, n);
+}
+EXPORT_SYMBOL_GPL(idle_notifier_unregister);
+#endif
 
 struct kmem_cache *task_xstate_cachep;
 EXPORT_SYMBOL_GPL(task_xstate_cachep);
@@ -370,6 +391,99 @@ static inline int hlt_use_halt(void)
 }
 #endif
 
+#ifndef CONFIG_SMP
+static inline void play_dead(void)
+{
+	BUG();
+}
+#endif
+
+#ifdef CONFIG_X86_64
+void enter_idle(void)
+{
+	percpu_write(is_idle, 1);
+	atomic_notifier_call_chain(&idle_notifier, IDLE_START, NULL);
+}
+
+static void __exit_idle(void)
+{
+	if (x86_test_and_clear_bit_percpu(0, is_idle) == 0)
+		return;
+	atomic_notifier_call_chain(&idle_notifier, IDLE_END, NULL);
+}
+
+/* Called from interrupts to signify idle end */
+void exit_idle(void)
+{
+	/* idle loop has pid 0 */
+	if (current->pid)
+		return;
+	__exit_idle();
+}
+#endif
+
+/*
+ * The idle thread. There's no useful work to be
+ * done, so just try to conserve power and have a
+ * low exit latency (ie sit in a loop waiting for
+ * somebody to say that they'd like to reschedule)
+ */
+void cpu_idle()
+{
+	/*
+	 * If we're the non-boot CPU, nothing set the stack canary up
+	 * for us.  CPU0 already has it initialized but no harm in
+	 * doing it again.  This is a good place for updating it, as
+	 * we wont ever return from this function (so the invalid
+	 * canaries already on the stack wont ever trigger).
+	 */
+	boot_init_stack_canary();
+	current_thread_info()->status |= TS_POLLING;
+
+	while (1) {
+		tick_nohz_idle_enter();
+
+		while (!need_resched()) {
+			rmb();
+
+			if (cpu_is_offline(smp_processor_id()))
+				play_dead();
+
+			/*
+			 * Idle routines should keep interrupts disabled
+			 * from here on, until they go to idle.
+			 * Otherwise, idle callbacks can misfire.
+			 */
+			local_touch_nmi();
+			local_irq_disable();
+
+			enter_idle();
+
+			/* Don't trace irqs off for idle */
+			stop_critical_timings();
+
+			/* enter_idle() needs rcu for notifiers */
+			rcu_idle_enter();
+
+			if (cpuidle_idle_call())
+				pm_idle();
+
+			rcu_idle_exit();
+			start_critical_timings();
+
+			/* In many cases the interrupt that ended idle
+			   has already called exit_idle. But some idle
+			   loops can be woken up without interrupt. */
+			__exit_idle();
+		}
+
+		tick_nohz_idle_exit();
+		preempt_enable_no_resched();
+		schedule();
+		preempt_disable();
+	}
+}
+
 /*
  * We use this if we don't have any better
  * idle routine..
diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c
index c08d1ff..9bf7c10 100644
--- a/arch/x86/kernel/process_32.c
+++ b/arch/x86/kernel/process_32.c
@@ -9,7 +9,6 @@
  * This file handles the architecture-dependent parts of process handling..
  */
 
-#include <linux/stackprotector.h>
 #include <linux/cpu.h>
 #include <linux/errno.h>
 #include <linux/sched.h>
@@ -31,14 +30,12 @@
 #include <linux/kallsyms.h>
 #include <linux/ptrace.h>
 #include <linux/personality.h>
-#include <linux/tick.h>
 #include <linux/percpu.h>
 #include <linux/prctl.h>
 #include <linux/ftrace.h>
 #include <linux/uaccess.h>
 #include <linux/io.h>
 #include <linux/kdebug.h>
-#include <linux/cpuidle.h>
 
 #include <asm/pgtable.h>
 #include <asm/system.h>
@@ -57,7 +54,6 @@
 #include <asm/idle.h>
 #include <asm/syscalls.h>
 #include <asm/debugreg.h>
-#include <asm/nmi.h>
 
 asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
 
@@ -69,62 +65,6 @@ unsigned long thread_saved_pc(struct task_struct *tsk)
 	return ((unsigned long *)tsk->thread.sp)[3];
 }
 
-#ifndef CONFIG_SMP
-static inline void play_dead(void)
-{
-	BUG();
-}
-#endif
-
-/*
- * The idle thread. There's no useful work to be
- * done, so just try to conserve power and have a
- * low exit latency (ie sit in a loop waiting for
- * somebody to say that they'd like to reschedule)
- */
-void cpu_idle(void)
-{
-	int cpu = smp_processor_id();
-
-	/*
-	 * If we're the non-boot CPU, nothing set the stack canary up
-	 * for us.  CPU0 already has it initialized but no harm in
-	 * doing it again.  This is a good place for updating it, as
-	 * we wont ever return from this function (so the invalid
-	 * canaries already on the stack wont ever trigger).
-	 */
-	boot_init_stack_canary();
-
-	current_thread_info()->status |= TS_POLLING;
-
-	/* endless idle loop with no priority at all */
-	while (1) {
-		tick_nohz_idle_enter();
-		rcu_idle_enter();
-		while (!need_resched()) {
-
-			check_pgt_cache();
-			rmb();
-
-			if (cpu_is_offline(cpu))
-				play_dead();
-
-			local_touch_nmi();
-			local_irq_disable();
-			/* Don't trace irqs off for idle */
-			stop_critical_timings();
-			if (cpuidle_idle_call())
-				pm_idle();
-			start_critical_timings();
-		}
-		rcu_idle_exit();
-		tick_nohz_idle_exit();
-		preempt_enable_no_resched();
-		schedule();
-		preempt_disable();
-	}
-}
-
 void __show_regs(struct pt_regs *regs, int all)
 {
 	unsigned long cr0 = 0L, cr2 = 0L, cr3 = 0L, cr4 = 0L;
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index cfa5c90..4f862d7 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -14,7 +14,6 @@
  * This file handles the architecture-dependent parts of process handling..
  */
 
-#include <linux/stackprotector.h>
 #include <linux/cpu.h>
 #include <linux/errno.h>
 #include <linux/sched.h>
@@ -32,12 +31,10 @@
 #include <linux/notifier.h>
 #include <linux/kprobes.h>
 #include <linux/kdebug.h>
-#include <linux/tick.h>
 #include <linux/prctl.h>
 #include <linux/uaccess.h>
 #include <linux/io.h>
 #include <linux/ftrace.h>
-#include <linux/cpuidle.h>
 
 #include <asm/pgtable.h>
 #include <asm/system.h>
@@ -51,116 +48,10 @@
 #include <asm/idle.h>
 #include <asm/syscalls.h>
 #include <asm/debugreg.h>
-#include <asm/nmi.h>
 
 asmlinkage extern void ret_from_fork(void);
 
 DEFINE_PER_CPU(unsigned long, old_rsp);
-static DEFINE_PER_CPU(unsigned char, is_idle);
-
-static ATOMIC_NOTIFIER_HEAD(idle_notifier);
-
-void idle_notifier_register(struct notifier_block *n)
-{
-	atomic_notifier_chain_register(&idle_notifier, n);
-}
-EXPORT_SYMBOL_GPL(idle_notifier_register);
-
-void idle_notifier_unregister(struct notifier_block *n)
-{
-	atomic_notifier_chain_unregister(&idle_notifier, n);
-}
-EXPORT_SYMBOL_GPL(idle_notifier_unregister);
-
-void enter_idle(void)
-{
-	percpu_write(is_idle, 1);
-	atomic_notifier_call_chain(&idle_notifier, IDLE_START, NULL);
-}
-
-static void __exit_idle(void)
-{
-	if (x86_test_and_clear_bit_percpu(0, is_idle) == 0)
-		return;
-	atomic_notifier_call_chain(&idle_notifier, IDLE_END, NULL);
-}
-
-/* Called from interrupts to signify idle end */
-void exit_idle(void)
-{
-	/* idle loop has pid 0 */
-	if (current->pid)
-		return;
-	__exit_idle();
-}
-
-#ifndef CONFIG_SMP
-static inline void play_dead(void)
-{
-	BUG();
-}
-#endif
-
-/*
- * The idle thread. There's no useful work to be
- * done, so just try to conserve power and have a
- * low exit latency (ie sit in a loop waiting for
- * somebody to say that they'd like to reschedule)
- */
-void cpu_idle(void)
-{
-	current_thread_info()->status |= TS_POLLING;
-
-	/*
-	 * If we're the non-boot CPU, nothing set the stack canary up
-	 * for us.  CPU0 already has it initialized but no harm in
-	 * doing it again.  This is a good place for updating it, as
-	 * we wont ever return from this function (so the invalid
-	 * canaries already on the stack wont ever trigger).
-	 */
-	boot_init_stack_canary();
-
-	/* endless idle loop with no priority at all */
-	while (1) {
-		tick_nohz_idle_enter();
-		while (!need_resched()) {
-
-			rmb();
-
-			if (cpu_is_offline(smp_processor_id()))
-				play_dead();
-			/*
-			 * Idle routines should keep interrupts disabled
-			 * from here on, until they go to idle.
-			 * Otherwise, idle callbacks can misfire.
-			 */
-			local_touch_nmi();
-			local_irq_disable();
-			enter_idle();
-			/* Don't trace irqs off for idle */
-			stop_critical_timings();
-
-			/* enter_idle() needs rcu for notifiers */
-			rcu_idle_enter();
-
-			if (cpuidle_idle_call())
-				pm_idle();
-
-			rcu_idle_exit();
-			start_critical_timings();
-
-			/* In many cases the interrupt that ended idle
-			   has already called exit_idle. But some idle
-			   loops can be woken up without interrupt. */
-			__exit_idle();
-		}
-
-		tick_nohz_idle_exit();
-		preempt_enable_no_resched();
-		schedule();
-		preempt_disable();
-	}
-}
 
 /* Prints also some state that isn't saved in the pt_regs */
 void __show_regs(struct pt_regs *regs, int all)
-- 
1.7.7.3

Re: [PATCH] x86: Merge x86_32 and x86_64 cpu_idle()

[H. Peter Anvin]

On 03/16/2012 01:18 PM, Richard Weinberger wrote:
> +/*
> + * The idle thread. There's no useful work to be
> + * done, so just try to conserve power and have a
> + * low exit latency (ie sit in a loop waiting for
> + * somebody to say that they'd like to reschedule)
> + */
> +void cpu_idle()

Thou shalt not, in the language of C, under any circumstances, on the
pain of death, declare or define a function with an empty set of
parentheses, for though in the language of C++ it meaneth the same as
(void), in C it meaneth (...) which is of meaningless as there be no
anchor argument by which the types of the varadic arguments can be
expressed, and which misleadeth the compiler into allowing unsavory code
and in some cases generate really ugly stuff for varadic handling.

	-hpa

[PATCH v2] x86: Merge x86_32 and x86_64 cpu_idle()

[Richard Weinberger]

Both functions are mostly identical, so we can merge them.

Signed-off-by: Richard Weinberger <richard@nod.at>
---
 arch/x86/include/asm/idle.h  |    1 +
 arch/x86/kernel/process.c    |  114 ++++++++++++++++++++++++++++++++++++++++++
 arch/x86/kernel/process_32.c |   60 ----------------------
 arch/x86/kernel/process_64.c |  109 ----------------------------------------
 4 files changed, 115 insertions(+), 169 deletions(-)

diff --git a/arch/x86/include/asm/idle.h b/arch/x86/include/asm/idle.h
index f49253d7..c5d1785 100644
--- a/arch/x86/include/asm/idle.h
+++ b/arch/x86/include/asm/idle.h
@@ -14,6 +14,7 @@ void exit_idle(void);
 #else /* !CONFIG_X86_64 */
 static inline void enter_idle(void) { }
 static inline void exit_idle(void) { }
+static inline void __exit_idle(void) { }
 #endif /* CONFIG_X86_64 */
 
 void amd_e400_remove_cpu(int cpu);
diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
index 15763af..11a2c29 100644
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -12,6 +12,9 @@
 #include <linux/user-return-notifier.h>
 #include <linux/dmi.h>
 #include <linux/utsname.h>
+#include <linux/stackprotector.h>
+#include <linux/tick.h>
+#include <linux/cpuidle.h>
 #include <trace/events/power.h>
 #include <linux/hw_breakpoint.h>
 #include <asm/cpu.h>
@@ -22,6 +25,24 @@
 #include <asm/uaccess.h>
 #include <asm/i387.h>
 #include <asm/debugreg.h>
+#include <asm/nmi.h>
+
+#ifdef CONFIG_X86_64
+static DEFINE_PER_CPU(unsigned char, is_idle);
+static ATOMIC_NOTIFIER_HEAD(idle_notifier);
+
+void idle_notifier_register(struct notifier_block *n)
+{
+	atomic_notifier_chain_register(&idle_notifier, n);
+}
+EXPORT_SYMBOL_GPL(idle_notifier_register);
+
+void idle_notifier_unregister(struct notifier_block *n)
+{
+	atomic_notifier_chain_unregister(&idle_notifier, n);
+}
+EXPORT_SYMBOL_GPL(idle_notifier_unregister);
+#endif
 
 struct kmem_cache *task_xstate_cachep;
 EXPORT_SYMBOL_GPL(task_xstate_cachep);
@@ -370,6 +391,99 @@ static inline int hlt_use_halt(void)
 }
 #endif
 
+#ifndef CONFIG_SMP
+static inline void play_dead(void)
+{
+	BUG();
+}
+#endif
+
+#ifdef CONFIG_X86_64
+void enter_idle(void)
+{
+	percpu_write(is_idle, 1);
+	atomic_notifier_call_chain(&idle_notifier, IDLE_START, NULL);
+}
+
+static void __exit_idle(void)
+{
+	if (x86_test_and_clear_bit_percpu(0, is_idle) == 0)
+		return;
+	atomic_notifier_call_chain(&idle_notifier, IDLE_END, NULL);
+}
+
+/* Called from interrupts to signify idle end */
+void exit_idle(void)
+{
+	/* idle loop has pid 0 */
+	if (current->pid)
+		return;
+	__exit_idle();
+}
+#endif
+
+/*
+ * The idle thread. There's no useful work to be
+ * done, so just try to conserve power and have a
+ * low exit latency (ie sit in a loop waiting for
+ * somebody to say that they'd like to reschedule)
+ */
+void cpu_idle(void)
+{
+	/*
+	 * If we're the non-boot CPU, nothing set the stack canary up
+	 * for us.  CPU0 already has it initialized but no harm in
+	 * doing it again.  This is a good place for updating it, as
+	 * we wont ever return from this function (so the invalid
+	 * canaries already on the stack wont ever trigger).
+	 */
+	boot_init_stack_canary();
+	current_thread_info()->status |= TS_POLLING;
+
+	while (1) {
+		tick_nohz_idle_enter();
+
+		while (!need_resched()) {
+			rmb();
+
+			if (cpu_is_offline(smp_processor_id()))
+				play_dead();
+
+			/*
+			 * Idle routines should keep interrupts disabled
+			 * from here on, until they go to idle.
+			 * Otherwise, idle callbacks can misfire.
+			 */
+			local_touch_nmi();
+			local_irq_disable();
+
+			enter_idle();
+
+			/* Don't trace irqs off for idle */
+			stop_critical_timings();
+
+			/* enter_idle() needs rcu for notifiers */
+			rcu_idle_enter();
+
+			if (cpuidle_idle_call())
+				pm_idle();
+
+			rcu_idle_exit();
+			start_critical_timings();
+
+			/* In many cases the interrupt that ended idle
+			   has already called exit_idle. But some idle
+			   loops can be woken up without interrupt. */
+			__exit_idle();
+		}
+
+		tick_nohz_idle_exit();
+		preempt_enable_no_resched();
+		schedule();
+		preempt_disable();
+	}
+}
+
 /*
  * We use this if we don't have any better
  * idle routine..
diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c
index c08d1ff..9bf7c10 100644
--- a/arch/x86/kernel/process_32.c
+++ b/arch/x86/kernel/process_32.c
@@ -9,7 +9,6 @@
  * This file handles the architecture-dependent parts of process handling..
  */
 
-#include <linux/stackprotector.h>
 #include <linux/cpu.h>
 #include <linux/errno.h>
 #include <linux/sched.h>
@@ -31,14 +30,12 @@
 #include <linux/kallsyms.h>
 #include <linux/ptrace.h>
 #include <linux/personality.h>
-#include <linux/tick.h>
 #include <linux/percpu.h>
 #include <linux/prctl.h>
 #include <linux/ftrace.h>
 #include <linux/uaccess.h>
 #include <linux/io.h>
 #include <linux/kdebug.h>
-#include <linux/cpuidle.h>
 
 #include <asm/pgtable.h>
 #include <asm/system.h>
@@ -57,7 +54,6 @@
 #include <asm/idle.h>
 #include <asm/syscalls.h>
 #include <asm/debugreg.h>
-#include <asm/nmi.h>
 
 asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
 
@@ -69,62 +65,6 @@ unsigned long thread_saved_pc(struct task_struct *tsk)
 	return ((unsigned long *)tsk->thread.sp)[3];
 }
 
-#ifndef CONFIG_SMP
-static inline void play_dead(void)
-{
-	BUG();
-}
-#endif
-
-/*
- * The idle thread. There's no useful work to be
- * done, so just try to conserve power and have a
- * low exit latency (ie sit in a loop waiting for
- * somebody to say that they'd like to reschedule)
- */
-void cpu_idle(void)
-{
-	int cpu = smp_processor_id();
-
-	/*
-	 * If we're the non-boot CPU, nothing set the stack canary up
-	 * for us.  CPU0 already has it initialized but no harm in
-	 * doing it again.  This is a good place for updating it, as
-	 * we wont ever return from this function (so the invalid
-	 * canaries already on the stack wont ever trigger).
-	 */
-	boot_init_stack_canary();
-
-	current_thread_info()->status |= TS_POLLING;
-
-	/* endless idle loop with no priority at all */
-	while (1) {
-		tick_nohz_idle_enter();
-		rcu_idle_enter();
-		while (!need_resched()) {
-
-			check_pgt_cache();
-			rmb();
-
-			if (cpu_is_offline(cpu))
-				play_dead();
-
-			local_touch_nmi();
-			local_irq_disable();
-			/* Don't trace irqs off for idle */
-			stop_critical_timings();
-			if (cpuidle_idle_call())
-				pm_idle();
-			start_critical_timings();
-		}
-		rcu_idle_exit();
-		tick_nohz_idle_exit();
-		preempt_enable_no_resched();
-		schedule();
-		preempt_disable();
-	}
-}
-
 void __show_regs(struct pt_regs *regs, int all)
 {
 	unsigned long cr0 = 0L, cr2 = 0L, cr3 = 0L, cr4 = 0L;
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index cfa5c90..4f862d7 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -14,7 +14,6 @@
  * This file handles the architecture-dependent parts of process handling..
  */
 
-#include <linux/stackprotector.h>
 #include <linux/cpu.h>
 #include <linux/errno.h>
 #include <linux/sched.h>
@@ -32,12 +31,10 @@
 #include <linux/notifier.h>
 #include <linux/kprobes.h>
 #include <linux/kdebug.h>
-#include <linux/tick.h>
 #include <linux/prctl.h>
 #include <linux/uaccess.h>
 #include <linux/io.h>
 #include <linux/ftrace.h>
-#include <linux/cpuidle.h>
 
 #include <asm/pgtable.h>
 #include <asm/system.h>
@@ -51,116 +48,10 @@
 #include <asm/idle.h>
 #include <asm/syscalls.h>
 #include <asm/debugreg.h>
-#include <asm/nmi.h>
 
 asmlinkage extern void ret_from_fork(void);
 
 DEFINE_PER_CPU(unsigned long, old_rsp);
-static DEFINE_PER_CPU(unsigned char, is_idle);
-
-static ATOMIC_NOTIFIER_HEAD(idle_notifier);
-
-void idle_notifier_register(struct notifier_block *n)
-{
-	atomic_notifier_chain_register(&idle_notifier, n);
-}
-EXPORT_SYMBOL_GPL(idle_notifier_register);
-
-void idle_notifier_unregister(struct notifier_block *n)
-{
-	atomic_notifier_chain_unregister(&idle_notifier, n);
-}
-EXPORT_SYMBOL_GPL(idle_notifier_unregister);
-
-void enter_idle(void)
-{
-	percpu_write(is_idle, 1);
-	atomic_notifier_call_chain(&idle_notifier, IDLE_START, NULL);
-}
-
-static void __exit_idle(void)
-{
-	if (x86_test_and_clear_bit_percpu(0, is_idle) == 0)
-		return;
-	atomic_notifier_call_chain(&idle_notifier, IDLE_END, NULL);
-}
-
-/* Called from interrupts to signify idle end */
-void exit_idle(void)
-{
-	/* idle loop has pid 0 */
-	if (current->pid)
-		return;
-	__exit_idle();
-}
-
-#ifndef CONFIG_SMP
-static inline void play_dead(void)
-{
-	BUG();
-}
-#endif
-
-/*
- * The idle thread. There's no useful work to be
- * done, so just try to conserve power and have a
- * low exit latency (ie sit in a loop waiting for
- * somebody to say that they'd like to reschedule)
- */
-void cpu_idle(void)
-{
-	current_thread_info()->status |= TS_POLLING;
-
-	/*
-	 * If we're the non-boot CPU, nothing set the stack canary up
-	 * for us.  CPU0 already has it initialized but no harm in
-	 * doing it again.  This is a good place for updating it, as
-	 * we wont ever return from this function (so the invalid
-	 * canaries already on the stack wont ever trigger).
-	 */
-	boot_init_stack_canary();
-
-	/* endless idle loop with no priority at all */
-	while (1) {
-		tick_nohz_idle_enter();
-		while (!need_resched()) {
-
-			rmb();
-
-			if (cpu_is_offline(smp_processor_id()))
-				play_dead();
-			/*
-			 * Idle routines should keep interrupts disabled
-			 * from here on, until they go to idle.
-			 * Otherwise, idle callbacks can misfire.
-			 */
-			local_touch_nmi();
-			local_irq_disable();
-			enter_idle();
-			/* Don't trace irqs off for idle */
-			stop_critical_timings();
-
-			/* enter_idle() needs rcu for notifiers */
-			rcu_idle_enter();
-
-			if (cpuidle_idle_call())
-				pm_idle();
-
-			rcu_idle_exit();
-			start_critical_timings();
-
-			/* In many cases the interrupt that ended idle
-			   has already called exit_idle. But some idle
-			   loops can be woken up without interrupt. */
-			__exit_idle();
-		}
-
-		tick_nohz_idle_exit();
-		preempt_enable_no_resched();
-		schedule();
-		preempt_disable();
-	}
-}
 
 /* Prints also some state that isn't saved in the pt_regs */
 void __show_regs(struct pt_regs *regs, int all)
-- 
1.7.7.3

Re: [PATCH v2] x86: Merge x86_32 and x86_64 cpu_idle()

[Frederic Weisbecker]

On Fri, Mar 16, 2012 at 10:40:10PM +0100, Richard Weinberger wrote:
> Both functions are mostly identical, so we can merge them.
> 
> Signed-off-by: Richard Weinberger <richard@nod.at>

Looks like a good idea.

Thanks.

Acked-by: Frederic Weisbecker <fweisbec@gmail.com>

Re: [PATCH v2] x86: Merge x86_32 and x86_64 cpu_idle()

[Ingo Molnar]

* Richard Weinberger <richard@nod.at> wrote:

> Both functions are mostly identical, so we can merge them.
> 
> Signed-off-by: Richard Weinberger <richard@nod.at>
> ---
>  arch/x86/include/asm/idle.h  |    1 +
>  arch/x86/kernel/process.c    |  114 ++++++++++++++++++++++++++++++++++++++++++
>  arch/x86/kernel/process_32.c |   60 ----------------------
>  arch/x86/kernel/process_64.c |  109 ----------------------------------------
>  4 files changed, 115 insertions(+), 169 deletions(-)

Doesn't apply on latest -tip:

patching file arch/x86/include/asm/idle.h
patching file arch/x86/kernel/process.c
Hunk #2 succeeded at 26 with fuzz 2 (offset 1 line).
Hunk #3 succeeded at 392 (offset 1 line).
patching file arch/x86/kernel/process_32.c
Hunk #3 succeeded at 55 (offset 1 line).
Hunk #4 FAILED at 65.
1 out of 4 hunks FAILED -- rejects in file arch/x86/kernel/process_32.c
patching file arch/x86/kernel/process_64.c
Hunk #3 FAILED at 48.
1 out of 3 hunks FAILED -- rejects in file arch/x86/kernel/process_64.c

Is a good idea otherwise.

Thanks,

	Ingo

Re: [PATCH v2] x86: Merge x86_32 and x86_64 cpu_idle()

[Richard Weinberger]

Am 23.03.2012 13:25, schrieb Ingo Molnar:
>
> * Richard Weinberger<richard@nod.at>  wrote:
>
>> Both functions are mostly identical, so we can merge them.
>>
>> Signed-off-by: Richard Weinberger<richard@nod.at>
>> ---
>>   arch/x86/include/asm/idle.h  |    1 +
>>   arch/x86/kernel/process.c    |  114 ++++++++++++++++++++++++++++++++++++++++++
>>   arch/x86/kernel/process_32.c |   60 ----------------------
>>   arch/x86/kernel/process_64.c |  109 ----------------------------------------
>>   4 files changed, 115 insertions(+), 169 deletions(-)
>
> Doesn't apply on latest -tip:
>
> patching file arch/x86/include/asm/idle.h
> patching file arch/x86/kernel/process.c
> Hunk #2 succeeded at 26 with fuzz 2 (offset 1 line).
> Hunk #3 succeeded at 392 (offset 1 line).
> patching file arch/x86/kernel/process_32.c
> Hunk #3 succeeded at 55 (offset 1 line).
> Hunk #4 FAILED at 65.
> 1 out of 4 hunks FAILED -- rejects in file arch/x86/kernel/process_32.c
> patching file arch/x86/kernel/process_64.c
> Hunk #3 FAILED at 48.
> 1 out of 3 hunks FAILED -- rejects in file arch/x86/kernel/process_64.c
>

It was based on Linus' tree.
I'll rebase it on -tip.

Thanks,
//richard

Re: [PATCH v2] x86: Merge x86_32 and x86_64 cpu_idle()

[Ingo Molnar]

* Richard Weinberger <richard@nod.at> wrote:

> Am 23.03.2012 13:25, schrieb Ingo Molnar:
> >
> >* Richard Weinberger<richard@nod.at>  wrote:
> >
> >>Both functions are mostly identical, so we can merge them.
> >>
> >>Signed-off-by: Richard Weinberger<richard@nod.at>
> >>---
> >>  arch/x86/include/asm/idle.h  |    1 +
> >>  arch/x86/kernel/process.c    |  114 ++++++++++++++++++++++++++++++++++++++++++
> >>  arch/x86/kernel/process_32.c |   60 ----------------------
> >>  arch/x86/kernel/process_64.c |  109 ----------------------------------------
> >>  4 files changed, 115 insertions(+), 169 deletions(-)
> >
> >Doesn't apply on latest -tip:
> >
> >patching file arch/x86/include/asm/idle.h
> >patching file arch/x86/kernel/process.c
> >Hunk #2 succeeded at 26 with fuzz 2 (offset 1 line).
> >Hunk #3 succeeded at 392 (offset 1 line).
> >patching file arch/x86/kernel/process_32.c
> >Hunk #3 succeeded at 55 (offset 1 line).
> >Hunk #4 FAILED at 65.
> >1 out of 4 hunks FAILED -- rejects in file arch/x86/kernel/process_32.c
> >patching file arch/x86/kernel/process_64.c
> >Hunk #3 FAILED at 48.
> >1 out of 3 hunks FAILED -- rejects in file arch/x86/kernel/process_64.c
> >
> 
> It was based on Linus' tree.

The conflicts were against Linus's tree - the merge window added 
new code there.

> I'll rebase it on -tip.

Thanks!

	Ingo

[PATCH] x86: Merge x86_32 and x86_64 cpu_idle()

[Richard Weinberger]

Both functions are mostly identical, so we can merge them.

Signed-off-by: Richard Weinberger <richard@nod.at>
---
 arch/x86/include/asm/idle.h  |    1 +
 arch/x86/kernel/process.c    |  114 ++++++++++++++++++++++++++++++++++++++++++
 arch/x86/kernel/process_32.c |   58 ---------------------
 arch/x86/kernel/process_64.c |  107 ---------------------------------------
 4 files changed, 115 insertions(+), 165 deletions(-)

diff --git a/arch/x86/include/asm/idle.h b/arch/x86/include/asm/idle.h
index f49253d7..c5d1785 100644
--- a/arch/x86/include/asm/idle.h
+++ b/arch/x86/include/asm/idle.h
@@ -14,6 +14,7 @@ void exit_idle(void);
 #else /* !CONFIG_X86_64 */
 static inline void enter_idle(void) { }
 static inline void exit_idle(void) { }
+static inline void __exit_idle(void) { }
 #endif /* CONFIG_X86_64 */
 
 void amd_e400_remove_cpu(int cpu);
diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
index 14baf78..29309c4 100644
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -12,6 +12,9 @@
 #include <linux/user-return-notifier.h>
 #include <linux/dmi.h>
 #include <linux/utsname.h>
+#include <linux/stackprotector.h>
+#include <linux/tick.h>
+#include <linux/cpuidle.h>
 #include <trace/events/power.h>
 #include <linux/hw_breakpoint.h>
 #include <asm/cpu.h>
@@ -23,6 +26,24 @@
 #include <asm/i387.h>
 #include <asm/fpu-internal.h>
 #include <asm/debugreg.h>
+#include <asm/nmi.h>
+
+#ifdef CONFIG_X86_64
+static DEFINE_PER_CPU(unsigned char, is_idle);
+static ATOMIC_NOTIFIER_HEAD(idle_notifier);
+
+void idle_notifier_register(struct notifier_block *n)
+{
+	atomic_notifier_chain_register(&idle_notifier, n);
+}
+EXPORT_SYMBOL_GPL(idle_notifier_register);
+
+void idle_notifier_unregister(struct notifier_block *n)
+{
+	atomic_notifier_chain_unregister(&idle_notifier, n);
+}
+EXPORT_SYMBOL_GPL(idle_notifier_unregister);
+#endif
 
 struct kmem_cache *task_xstate_cachep;
 EXPORT_SYMBOL_GPL(task_xstate_cachep);
@@ -371,6 +392,99 @@ static inline int hlt_use_halt(void)
 }
 #endif
 
+#ifndef CONFIG_SMP
+static inline void play_dead(void)
+{
+	BUG();
+}
+#endif
+
+#ifdef CONFIG_X86_64
+void enter_idle(void)
+{
+	percpu_write(is_idle, 1);
+	atomic_notifier_call_chain(&idle_notifier, IDLE_START, NULL);
+}
+
+static void __exit_idle(void)
+{
+	if (x86_test_and_clear_bit_percpu(0, is_idle) == 0)
+		return;
+	atomic_notifier_call_chain(&idle_notifier, IDLE_END, NULL);
+}
+
+/* Called from interrupts to signify idle end */
+void exit_idle(void)
+{
+	/* idle loop has pid 0 */
+	if (current->pid)
+		return;
+	__exit_idle();
+}
+#endif
+
+/*
+ * The idle thread. There's no useful work to be
+ * done, so just try to conserve power and have a
+ * low exit latency (ie sit in a loop waiting for
+ * somebody to say that they'd like to reschedule)
+ */
+void cpu_idle(void)
+{
+	/*
+	 * If we're the non-boot CPU, nothing set the stack canary up
+	 * for us.  CPU0 already has it initialized but no harm in
+	 * doing it again.  This is a good place for updating it, as
+	 * we wont ever return from this function (so the invalid
+	 * canaries already on the stack wont ever trigger).
+	 */
+	boot_init_stack_canary();
+	current_thread_info()->status |= TS_POLLING;
+
+	while (1) {
+		tick_nohz_idle_enter();
+
+		while (!need_resched()) {
+			rmb();
+
+			if (cpu_is_offline(smp_processor_id()))
+				play_dead();
+
+			/*
+			 * Idle routines should keep interrupts disabled
+			 * from here on, until they go to idle.
+			 * Otherwise, idle callbacks can misfire.
+			 */
+			local_touch_nmi();
+			local_irq_disable();
+
+			enter_idle();
+
+			/* Don't trace irqs off for idle */
+			stop_critical_timings();
+
+			/* enter_idle() needs rcu for notifiers */
+			rcu_idle_enter();
+
+			if (cpuidle_idle_call())
+				pm_idle();
+
+			rcu_idle_exit();
+			start_critical_timings();
+
+			/* In many cases the interrupt that ended idle
+			   has already called exit_idle. But some idle
+			   loops can be woken up without interrupt. */
+			__exit_idle();
+		}
+
+		tick_nohz_idle_exit();
+		preempt_enable_no_resched();
+		schedule();
+		preempt_disable();
+	}
+}
+
 /*
  * We use this if we don't have any better
  * idle routine..
diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c
index 9d7d484..ea207c2 100644
--- a/arch/x86/kernel/process_32.c
+++ b/arch/x86/kernel/process_32.c
@@ -9,7 +9,6 @@
  * This file handles the architecture-dependent parts of process handling..
  */
 
-#include <linux/stackprotector.h>
 #include <linux/cpu.h>
 #include <linux/errno.h>
 #include <linux/sched.h>
@@ -31,14 +30,12 @@
 #include <linux/kallsyms.h>
 #include <linux/ptrace.h>
 #include <linux/personality.h>
-#include <linux/tick.h>
 #include <linux/percpu.h>
 #include <linux/prctl.h>
 #include <linux/ftrace.h>
 #include <linux/uaccess.h>
 #include <linux/io.h>
 #include <linux/kdebug.h>
-#include <linux/cpuidle.h>
 
 #include <asm/pgtable.h>
 #include <asm/system.h>
@@ -58,7 +55,6 @@
 #include <asm/idle.h>
 #include <asm/syscalls.h>
 #include <asm/debugreg.h>
-#include <asm/nmi.h>
 
 asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
 
@@ -70,60 +66,6 @@ unsigned long thread_saved_pc(struct task_struct *tsk)
 	return ((unsigned long *)tsk->thread.sp)[3];
 }
 
-#ifndef CONFIG_SMP
-static inline void play_dead(void)
-{
-	BUG();
-}
-#endif
-
-/*
- * The idle thread. There's no useful work to be
- * done, so just try to conserve power and have a
- * low exit latency (ie sit in a loop waiting for
- * somebody to say that they'd like to reschedule)
- */
-void cpu_idle(void)
-{
-	int cpu = smp_processor_id();
-
-	/*
-	 * If we're the non-boot CPU, nothing set the stack canary up
-	 * for us.  CPU0 already has it initialized but no harm in
-	 * doing it again.  This is a good place for updating it, as
-	 * we wont ever return from this function (so the invalid
-	 * canaries already on the stack wont ever trigger).
-	 */
-	boot_init_stack_canary();
-
-	current_thread_info()->status |= TS_POLLING;
-
-	/* endless idle loop with no priority at all */
-	while (1) {
-		tick_nohz_idle_enter();
-		rcu_idle_enter();
-		while (!need_resched()) {
-
-			check_pgt_cache();
-			rmb();
-
-			if (cpu_is_offline(cpu))
-				play_dead();
-
-			local_touch_nmi();
-			local_irq_disable();
-			/* Don't trace irqs off for idle */
-			stop_critical_timings();
-			if (cpuidle_idle_call())
-				pm_idle();
-			start_critical_timings();
-		}
-		rcu_idle_exit();
-		tick_nohz_idle_exit();
-		schedule_preempt_disabled();
-	}
-}
-
 void __show_regs(struct pt_regs *regs, int all)
 {
 	unsigned long cr0 = 0L, cr2 = 0L, cr3 = 0L, cr4 = 0L;
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index 1deb467..d367757 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -14,7 +14,6 @@
  * This file handles the architecture-dependent parts of process handling..
  */
 
-#include <linux/stackprotector.h>
 #include <linux/cpu.h>
 #include <linux/errno.h>
 #include <linux/sched.h>
@@ -32,12 +31,10 @@
 #include <linux/notifier.h>
 #include <linux/kprobes.h>
 #include <linux/kdebug.h>
-#include <linux/tick.h>
 #include <linux/prctl.h>
 #include <linux/uaccess.h>
 #include <linux/io.h>
 #include <linux/ftrace.h>
-#include <linux/cpuidle.h>
 
 #include <asm/pgtable.h>
 #include <asm/system.h>
@@ -52,114 +49,10 @@
 #include <asm/idle.h>
 #include <asm/syscalls.h>
 #include <asm/debugreg.h>
-#include <asm/nmi.h>
 
 asmlinkage extern void ret_from_fork(void);
 
 DEFINE_PER_CPU(unsigned long, old_rsp);
-static DEFINE_PER_CPU(unsigned char, is_idle);
-
-static ATOMIC_NOTIFIER_HEAD(idle_notifier);
-
-void idle_notifier_register(struct notifier_block *n)
-{
-	atomic_notifier_chain_register(&idle_notifier, n);
-}
-EXPORT_SYMBOL_GPL(idle_notifier_register);
-
-void idle_notifier_unregister(struct notifier_block *n)
-{
-	atomic_notifier_chain_unregister(&idle_notifier, n);
-}
-EXPORT_SYMBOL_GPL(idle_notifier_unregister);
-
-void enter_idle(void)
-{
-	percpu_write(is_idle, 1);
-	atomic_notifier_call_chain(&idle_notifier, IDLE_START, NULL);
-}
-
-static void __exit_idle(void)
-{
-	if (x86_test_and_clear_bit_percpu(0, is_idle) == 0)
-		return;
-	atomic_notifier_call_chain(&idle_notifier, IDLE_END, NULL);
-}
-
-/* Called from interrupts to signify idle end */
-void exit_idle(void)
-{
-	/* idle loop has pid 0 */
-	if (current->pid)
-		return;
-	__exit_idle();
-}
-
-#ifndef CONFIG_SMP
-static inline void play_dead(void)
-{
-	BUG();
-}
-#endif
-
-/*
- * The idle thread. There's no useful work to be
- * done, so just try to conserve power and have a
- * low exit latency (ie sit in a loop waiting for
- * somebody to say that they'd like to reschedule)
- */
-void cpu_idle(void)
-{
-	current_thread_info()->status |= TS_POLLING;
-
-	/*
-	 * If we're the non-boot CPU, nothing set the stack canary up
-	 * for us.  CPU0 already has it initialized but no harm in
-	 * doing it again.  This is a good place for updating it, as
-	 * we wont ever return from this function (so the invalid
-	 * canaries already on the stack wont ever trigger).
-	 */
-	boot_init_stack_canary();
-
-	/* endless idle loop with no priority at all */
-	while (1) {
-		tick_nohz_idle_enter();
-		while (!need_resched()) {
-
-			rmb();
-
-			if (cpu_is_offline(smp_processor_id()))
-				play_dead();
-			/*
-			 * Idle routines should keep interrupts disabled
-			 * from here on, until they go to idle.
-			 * Otherwise, idle callbacks can misfire.
-			 */
-			local_touch_nmi();
-			local_irq_disable();
-			enter_idle();
-			/* Don't trace irqs off for idle */
-			stop_critical_timings();
-
-			/* enter_idle() needs rcu for notifiers */
-			rcu_idle_enter();
-
-			if (cpuidle_idle_call())
-				pm_idle();
-
-			rcu_idle_exit();
-			start_critical_timings();
-
-			/* In many cases the interrupt that ended idle
-			   has already called exit_idle. But some idle
-			   loops can be woken up without interrupt. */
-			__exit_idle();
-		}
-
-		tick_nohz_idle_exit();
-		schedule_preempt_disabled();
-	}
-}
 
 /* Prints also some state that isn't saved in the pt_regs */
 void __show_regs(struct pt_regs *regs, int all)
-- 
1.7.7.3

Re: [PATCH] x86: Merge x86_32 and x86_64 cpu_idle()

[Ingo Molnar]

* Richard Weinberger <richard@nod.at> wrote:

> Both functions are mostly identical, so we can merge them.

Okay, so while looking at the patch I got a bit worried about 
the 'mostly' qualifier ;-)

You could ease that worry by adding an explanation to the 
changelog that itemizes the differences, explains which 
architecture is affected by the changes in what way and gives us 
the warm fuzzy feeling that everything has been considered and 
no ill can come out of using a 'mostly' identical idling 
function in the future.

( You should also pick up Frederic's ack for the next
  submission of this patch. )

Thanks,

	Ingo

[PATCH] x86: Merge x86_32 and x86_64 cpu_idle()

[Richard Weinberger]

Both functions are mostly identical.
The differences are:

- x86_32's cpu_idle() makes use of check_pgt_cache(), which is a nop
  on both x86_32 and x86_64.
- x86_64's cpu_idle() uses enter/__exit_idle/(), on x86_32 these
  function are a nop.
- In contrast to x86_32, x86_64 calls rcu_idle_enter/exit() in the
  innermost loop because idle notifications need RCU.
  Calling these function on x86_32 also in the innermost loop does not
  hurt.

So we can merge both functions.

Signed-off-by: Richard Weinberger <richard@nod.at>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
---
 arch/x86/include/asm/idle.h  |    1 +
 arch/x86/kernel/process.c    |  114 ++++++++++++++++++++++++++++++++++++++++++
 arch/x86/kernel/process_32.c |   58 ---------------------
 arch/x86/kernel/process_64.c |  107 ---------------------------------------
 4 files changed, 115 insertions(+), 165 deletions(-)

diff --git a/arch/x86/include/asm/idle.h b/arch/x86/include/asm/idle.h
index f49253d7..c5d1785 100644
--- a/arch/x86/include/asm/idle.h
+++ b/arch/x86/include/asm/idle.h
@@ -14,6 +14,7 @@ void exit_idle(void);
 #else /* !CONFIG_X86_64 */
 static inline void enter_idle(void) { }
 static inline void exit_idle(void) { }
+static inline void __exit_idle(void) { }
 #endif /* CONFIG_X86_64 */
 
 void amd_e400_remove_cpu(int cpu);
diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
index 14baf78..29309c4 100644
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -12,6 +12,9 @@
 #include <linux/user-return-notifier.h>
 #include <linux/dmi.h>
 #include <linux/utsname.h>
+#include <linux/stackprotector.h>
+#include <linux/tick.h>
+#include <linux/cpuidle.h>
 #include <trace/events/power.h>
 #include <linux/hw_breakpoint.h>
 #include <asm/cpu.h>
@@ -23,6 +26,24 @@
 #include <asm/i387.h>
 #include <asm/fpu-internal.h>
 #include <asm/debugreg.h>
+#include <asm/nmi.h>
+
+#ifdef CONFIG_X86_64
+static DEFINE_PER_CPU(unsigned char, is_idle);
+static ATOMIC_NOTIFIER_HEAD(idle_notifier);
+
+void idle_notifier_register(struct notifier_block *n)
+{
+	atomic_notifier_chain_register(&idle_notifier, n);
+}
+EXPORT_SYMBOL_GPL(idle_notifier_register);
+
+void idle_notifier_unregister(struct notifier_block *n)
+{
+	atomic_notifier_chain_unregister(&idle_notifier, n);
+}
+EXPORT_SYMBOL_GPL(idle_notifier_unregister);
+#endif
 
 struct kmem_cache *task_xstate_cachep;
 EXPORT_SYMBOL_GPL(task_xstate_cachep);
@@ -371,6 +392,99 @@ static inline int hlt_use_halt(void)
 }
 #endif
 
+#ifndef CONFIG_SMP
+static inline void play_dead(void)
+{
+	BUG();
+}
+#endif
+
+#ifdef CONFIG_X86_64
+void enter_idle(void)
+{
+	percpu_write(is_idle, 1);
+	atomic_notifier_call_chain(&idle_notifier, IDLE_START, NULL);
+}
+
+static void __exit_idle(void)
+{
+	if (x86_test_and_clear_bit_percpu(0, is_idle) == 0)
+		return;
+	atomic_notifier_call_chain(&idle_notifier, IDLE_END, NULL);
+}
+
+/* Called from interrupts to signify idle end */
+void exit_idle(void)
+{
+	/* idle loop has pid 0 */
+	if (current->pid)
+		return;
+	__exit_idle();
+}
+#endif
+
+/*
+ * The idle thread. There's no useful work to be
+ * done, so just try to conserve power and have a
+ * low exit latency (ie sit in a loop waiting for
+ * somebody to say that they'd like to reschedule)
+ */
+void cpu_idle(void)
+{
+	/*
+	 * If we're the non-boot CPU, nothing set the stack canary up
+	 * for us.  CPU0 already has it initialized but no harm in
+	 * doing it again.  This is a good place for updating it, as
+	 * we wont ever return from this function (so the invalid
+	 * canaries already on the stack wont ever trigger).
+	 */
+	boot_init_stack_canary();
+	current_thread_info()->status |= TS_POLLING;
+
+	while (1) {
+		tick_nohz_idle_enter();
+
+		while (!need_resched()) {
+			rmb();
+
+			if (cpu_is_offline(smp_processor_id()))
+				play_dead();
+
+			/*
+			 * Idle routines should keep interrupts disabled
+			 * from here on, until they go to idle.
+			 * Otherwise, idle callbacks can misfire.
+			 */
+			local_touch_nmi();
+			local_irq_disable();
+
+			enter_idle();
+
+			/* Don't trace irqs off for idle */
+			stop_critical_timings();
+
+			/* enter_idle() needs rcu for notifiers */
+			rcu_idle_enter();
+
+			if (cpuidle_idle_call())
+				pm_idle();
+
+			rcu_idle_exit();
+			start_critical_timings();
+
+			/* In many cases the interrupt that ended idle
+			   has already called exit_idle. But some idle
+			   loops can be woken up without interrupt. */
+			__exit_idle();
+		}
+
+		tick_nohz_idle_exit();
+		preempt_enable_no_resched();
+		schedule();
+		preempt_disable();
+	}
+}
+
 /*
  * We use this if we don't have any better
  * idle routine..
diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c
index 9d7d484..ea207c2 100644
--- a/arch/x86/kernel/process_32.c
+++ b/arch/x86/kernel/process_32.c
@@ -9,7 +9,6 @@
  * This file handles the architecture-dependent parts of process handling..
  */
 
-#include <linux/stackprotector.h>
 #include <linux/cpu.h>
 #include <linux/errno.h>
 #include <linux/sched.h>
@@ -31,14 +30,12 @@
 #include <linux/kallsyms.h>
 #include <linux/ptrace.h>
 #include <linux/personality.h>
-#include <linux/tick.h>
 #include <linux/percpu.h>
 #include <linux/prctl.h>
 #include <linux/ftrace.h>
 #include <linux/uaccess.h>
 #include <linux/io.h>
 #include <linux/kdebug.h>
-#include <linux/cpuidle.h>
 
 #include <asm/pgtable.h>
 #include <asm/system.h>
@@ -58,7 +55,6 @@
 #include <asm/idle.h>
 #include <asm/syscalls.h>
 #include <asm/debugreg.h>
-#include <asm/nmi.h>
 
 asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
 
@@ -70,60 +66,6 @@ unsigned long thread_saved_pc(struct task_struct *tsk)
 	return ((unsigned long *)tsk->thread.sp)[3];
 }
 
-#ifndef CONFIG_SMP
-static inline void play_dead(void)
-{
-	BUG();
-}
-#endif
-
-/*
- * The idle thread. There's no useful work to be
- * done, so just try to conserve power and have a
- * low exit latency (ie sit in a loop waiting for
- * somebody to say that they'd like to reschedule)
- */
-void cpu_idle(void)
-{
-	int cpu = smp_processor_id();
-
-	/*
-	 * If we're the non-boot CPU, nothing set the stack canary up
-	 * for us.  CPU0 already has it initialized but no harm in
-	 * doing it again.  This is a good place for updating it, as
-	 * we wont ever return from this function (so the invalid
-	 * canaries already on the stack wont ever trigger).
-	 */
-	boot_init_stack_canary();
-
-	current_thread_info()->status |= TS_POLLING;
-
-	/* endless idle loop with no priority at all */
-	while (1) {
-		tick_nohz_idle_enter();
-		rcu_idle_enter();
-		while (!need_resched()) {
-
-			check_pgt_cache();
-			rmb();
-
-			if (cpu_is_offline(cpu))
-				play_dead();
-
-			local_touch_nmi();
-			local_irq_disable();
-			/* Don't trace irqs off for idle */
-			stop_critical_timings();
-			if (cpuidle_idle_call())
-				pm_idle();
-			start_critical_timings();
-		}
-		rcu_idle_exit();
-		tick_nohz_idle_exit();
-		schedule_preempt_disabled();
-	}
-}
-
 void __show_regs(struct pt_regs *regs, int all)
 {
 	unsigned long cr0 = 0L, cr2 = 0L, cr3 = 0L, cr4 = 0L;
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index 1deb467..d367757 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -14,7 +14,6 @@
  * This file handles the architecture-dependent parts of process handling..
  */
 
-#include <linux/stackprotector.h>
 #include <linux/cpu.h>
 #include <linux/errno.h>
 #include <linux/sched.h>
@@ -32,12 +31,10 @@
 #include <linux/notifier.h>
 #include <linux/kprobes.h>
 #include <linux/kdebug.h>
-#include <linux/tick.h>
 #include <linux/prctl.h>
 #include <linux/uaccess.h>
 #include <linux/io.h>
 #include <linux/ftrace.h>
-#include <linux/cpuidle.h>
 
 #include <asm/pgtable.h>
 #include <asm/system.h>
@@ -52,114 +49,10 @@
 #include <asm/idle.h>
 #include <asm/syscalls.h>
 #include <asm/debugreg.h>
-#include <asm/nmi.h>
 
 asmlinkage extern void ret_from_fork(void);
 
 DEFINE_PER_CPU(unsigned long, old_rsp);
-static DEFINE_PER_CPU(unsigned char, is_idle);
-
-static ATOMIC_NOTIFIER_HEAD(idle_notifier);
-
-void idle_notifier_register(struct notifier_block *n)
-{
-	atomic_notifier_chain_register(&idle_notifier, n);
-}
-EXPORT_SYMBOL_GPL(idle_notifier_register);
-
-void idle_notifier_unregister(struct notifier_block *n)
-{
-	atomic_notifier_chain_unregister(&idle_notifier, n);
-}
-EXPORT_SYMBOL_GPL(idle_notifier_unregister);
-
-void enter_idle(void)
-{
-	percpu_write(is_idle, 1);
-	atomic_notifier_call_chain(&idle_notifier, IDLE_START, NULL);
-}
-
-static void __exit_idle(void)
-{
-	if (x86_test_and_clear_bit_percpu(0, is_idle) == 0)
-		return;
-	atomic_notifier_call_chain(&idle_notifier, IDLE_END, NULL);
-}
-
-/* Called from interrupts to signify idle end */
-void exit_idle(void)
-{
-	/* idle loop has pid 0 */
-	if (current->pid)
-		return;
-	__exit_idle();
-}
-
-#ifndef CONFIG_SMP
-static inline void play_dead(void)
-{
-	BUG();
-}
-#endif
-
-/*
- * The idle thread. There's no useful work to be
- * done, so just try to conserve power and have a
- * low exit latency (ie sit in a loop waiting for
- * somebody to say that they'd like to reschedule)
- */
-void cpu_idle(void)
-{
-	current_thread_info()->status |= TS_POLLING;
-
-	/*
-	 * If we're the non-boot CPU, nothing set the stack canary up
-	 * for us.  CPU0 already has it initialized but no harm in
-	 * doing it again.  This is a good place for updating it, as
-	 * we wont ever return from this function (so the invalid
-	 * canaries already on the stack wont ever trigger).
-	 */
-	boot_init_stack_canary();
-
-	/* endless idle loop with no priority at all */
-	while (1) {
-		tick_nohz_idle_enter();
-		while (!need_resched()) {
-
-			rmb();
-
-			if (cpu_is_offline(smp_processor_id()))
-				play_dead();
-			/*
-			 * Idle routines should keep interrupts disabled
-			 * from here on, until they go to idle.
-			 * Otherwise, idle callbacks can misfire.
-			 */
-			local_touch_nmi();
-			local_irq_disable();
-			enter_idle();
-			/* Don't trace irqs off for idle */
-			stop_critical_timings();
-
-			/* enter_idle() needs rcu for notifiers */
-			rcu_idle_enter();
-
-			if (cpuidle_idle_call())
-				pm_idle();
-
-			rcu_idle_exit();
-			start_critical_timings();
-
-			/* In many cases the interrupt that ended idle
-			   has already called exit_idle. But some idle
-			   loops can be woken up without interrupt. */
-			__exit_idle();
-		}
-
-		tick_nohz_idle_exit();
-		schedule_preempt_disabled();
-	}
-}
 
 /* Prints also some state that isn't saved in the pt_regs */
 void __show_regs(struct pt_regs *regs, int all)
-- 
1.7.7.3

[tip:x86/urgent] x86: Merge the x86_32 and x86_64 cpu_idle() functions

[tip-bot for Richard Weinberger]

Commit-ID:  90e240142bd31ff10aeda5a280a53153f4eff004
Gitweb:     http://git.kernel.org/tip/90e240142bd31ff10aeda5a280a53153f4eff004
Author:     Richard Weinberger <richard@nod.at>
AuthorDate: Sun, 25 Mar 2012 23:00:04 +0200
Committer:  Ingo Molnar <mingo@kernel.org>
CommitDate: Mon, 26 Mar 2012 03:16:07 +0200

x86: Merge the x86_32 and x86_64 cpu_idle() functions

Both functions are mostly identical.
The differences are:

- x86_32's cpu_idle() makes use of check_pgt_cache(), which is a
  nop on both x86_32 and x86_64.

- x86_64's cpu_idle() uses enter/__exit_idle/(), on x86_32 these
  function are a nop.

- In contrast to x86_32, x86_64 calls rcu_idle_enter/exit() in
  the innermost loop because idle notifications need RCU.
  Calling these function on x86_32 also in the innermost loop
  does not hurt.

So we can merge both functions.

Signed-off-by: Richard Weinberger <richard@nod.at>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: paulmck@linux.vnet.ibm.com
Cc: josh@joshtriplett.org
Cc: tj@kernel.org
Link: http://lkml.kernel.org/r/1332709204-22496-1-git-send-email-richard@nod.at
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 arch/x86/include/asm/idle.h  |    1 +
 arch/x86/kernel/process.c    |  114 ++++++++++++++++++++++++++++++++++++++++++
 arch/x86/kernel/process_32.c |   58 ---------------------
 arch/x86/kernel/process_64.c |  107 ---------------------------------------
 4 files changed, 115 insertions(+), 165 deletions(-)

diff --git a/arch/x86/include/asm/idle.h b/arch/x86/include/asm/idle.h
index f49253d7..c5d1785 100644
--- a/arch/x86/include/asm/idle.h
+++ b/arch/x86/include/asm/idle.h
@@ -14,6 +14,7 @@ void exit_idle(void);
 #else /* !CONFIG_X86_64 */
 static inline void enter_idle(void) { }
 static inline void exit_idle(void) { }
+static inline void __exit_idle(void) { }
 #endif /* CONFIG_X86_64 */
 
 void amd_e400_remove_cpu(int cpu);
diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
index 14baf78..29309c4 100644
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -12,6 +12,9 @@
 #include <linux/user-return-notifier.h>
 #include <linux/dmi.h>
 #include <linux/utsname.h>
+#include <linux/stackprotector.h>
+#include <linux/tick.h>
+#include <linux/cpuidle.h>
 #include <trace/events/power.h>
 #include <linux/hw_breakpoint.h>
 #include <asm/cpu.h>
@@ -23,6 +26,24 @@
 #include <asm/i387.h>
 #include <asm/fpu-internal.h>
 #include <asm/debugreg.h>
+#include <asm/nmi.h>
+
+#ifdef CONFIG_X86_64
+static DEFINE_PER_CPU(unsigned char, is_idle);
+static ATOMIC_NOTIFIER_HEAD(idle_notifier);
+
+void idle_notifier_register(struct notifier_block *n)
+{
+	atomic_notifier_chain_register(&idle_notifier, n);
+}
+EXPORT_SYMBOL_GPL(idle_notifier_register);
+
+void idle_notifier_unregister(struct notifier_block *n)
+{
+	atomic_notifier_chain_unregister(&idle_notifier, n);
+}
+EXPORT_SYMBOL_GPL(idle_notifier_unregister);
+#endif
 
 struct kmem_cache *task_xstate_cachep;
 EXPORT_SYMBOL_GPL(task_xstate_cachep);
@@ -371,6 +392,99 @@ static inline int hlt_use_halt(void)
 }
 #endif
 
+#ifndef CONFIG_SMP
+static inline void play_dead(void)
+{
+	BUG();
+}
+#endif
+
+#ifdef CONFIG_X86_64
+void enter_idle(void)
+{
+	percpu_write(is_idle, 1);
+	atomic_notifier_call_chain(&idle_notifier, IDLE_START, NULL);
+}
+
+static void __exit_idle(void)
+{
+	if (x86_test_and_clear_bit_percpu(0, is_idle) == 0)
+		return;
+	atomic_notifier_call_chain(&idle_notifier, IDLE_END, NULL);
+}
+
+/* Called from interrupts to signify idle end */
+void exit_idle(void)
+{
+	/* idle loop has pid 0 */
+	if (current->pid)
+		return;
+	__exit_idle();
+}
+#endif
+
+/*
+ * The idle thread. There's no useful work to be
+ * done, so just try to conserve power and have a
+ * low exit latency (ie sit in a loop waiting for
+ * somebody to say that they'd like to reschedule)
+ */
+void cpu_idle(void)
+{
+	/*
+	 * If we're the non-boot CPU, nothing set the stack canary up
+	 * for us.  CPU0 already has it initialized but no harm in
+	 * doing it again.  This is a good place for updating it, as
+	 * we wont ever return from this function (so the invalid
+	 * canaries already on the stack wont ever trigger).
+	 */
+	boot_init_stack_canary();
+	current_thread_info()->status |= TS_POLLING;
+
+	while (1) {
+		tick_nohz_idle_enter();
+
+		while (!need_resched()) {
+			rmb();
+
+			if (cpu_is_offline(smp_processor_id()))
+				play_dead();
+
+			/*
+			 * Idle routines should keep interrupts disabled
+			 * from here on, until they go to idle.
+			 * Otherwise, idle callbacks can misfire.
+			 */
+			local_touch_nmi();
+			local_irq_disable();
+
+			enter_idle();
+
+			/* Don't trace irqs off for idle */
+			stop_critical_timings();
+
+			/* enter_idle() needs rcu for notifiers */
+			rcu_idle_enter();
+
+			if (cpuidle_idle_call())
+				pm_idle();
+
+			rcu_idle_exit();
+			start_critical_timings();
+
+			/* In many cases the interrupt that ended idle
+			   has already called exit_idle. But some idle
+			   loops can be woken up without interrupt. */
+			__exit_idle();
+		}
+
+		tick_nohz_idle_exit();
+		preempt_enable_no_resched();
+		schedule();
+		preempt_disable();
+	}
+}
+
 /*
  * We use this if we don't have any better
  * idle routine..
diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c
index 9d7d484..ea207c2 100644
--- a/arch/x86/kernel/process_32.c
+++ b/arch/x86/kernel/process_32.c
@@ -9,7 +9,6 @@
  * This file handles the architecture-dependent parts of process handling..
  */
 
-#include <linux/stackprotector.h>
 #include <linux/cpu.h>
 #include <linux/errno.h>
 #include <linux/sched.h>
@@ -31,14 +30,12 @@
 #include <linux/kallsyms.h>
 #include <linux/ptrace.h>
 #include <linux/personality.h>
-#include <linux/tick.h>
 #include <linux/percpu.h>
 #include <linux/prctl.h>
 #include <linux/ftrace.h>
 #include <linux/uaccess.h>
 #include <linux/io.h>
 #include <linux/kdebug.h>
-#include <linux/cpuidle.h>
 
 #include <asm/pgtable.h>
 #include <asm/system.h>
@@ -58,7 +55,6 @@
 #include <asm/idle.h>
 #include <asm/syscalls.h>
 #include <asm/debugreg.h>
-#include <asm/nmi.h>
 
 asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
 
@@ -70,60 +66,6 @@ unsigned long thread_saved_pc(struct task_struct *tsk)
 	return ((unsigned long *)tsk->thread.sp)[3];
 }
 
-#ifndef CONFIG_SMP
-static inline void play_dead(void)
-{
-	BUG();
-}
-#endif
-
-/*
- * The idle thread. There's no useful work to be
- * done, so just try to conserve power and have a
- * low exit latency (ie sit in a loop waiting for
- * somebody to say that they'd like to reschedule)
- */
-void cpu_idle(void)
-{
-	int cpu = smp_processor_id();
-
-	/*
-	 * If we're the non-boot CPU, nothing set the stack canary up
-	 * for us.  CPU0 already has it initialized but no harm in
-	 * doing it again.  This is a good place for updating it, as
-	 * we wont ever return from this function (so the invalid
-	 * canaries already on the stack wont ever trigger).
-	 */
-	boot_init_stack_canary();
-
-	current_thread_info()->status |= TS_POLLING;
-
-	/* endless idle loop with no priority at all */
-	while (1) {
-		tick_nohz_idle_enter();
-		rcu_idle_enter();
-		while (!need_resched()) {
-
-			check_pgt_cache();
-			rmb();
-
-			if (cpu_is_offline(cpu))
-				play_dead();
-
-			local_touch_nmi();
-			local_irq_disable();
-			/* Don't trace irqs off for idle */
-			stop_critical_timings();
-			if (cpuidle_idle_call())
-				pm_idle();
-			start_critical_timings();
-		}
-		rcu_idle_exit();
-		tick_nohz_idle_exit();
-		schedule_preempt_disabled();
-	}
-}
-
 void __show_regs(struct pt_regs *regs, int all)
 {
 	unsigned long cr0 = 0L, cr2 = 0L, cr3 = 0L, cr4 = 0L;
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index 292da13..ce5e34f 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -14,7 +14,6 @@
  * This file handles the architecture-dependent parts of process handling..
  */
 
-#include <linux/stackprotector.h>
 #include <linux/cpu.h>
 #include <linux/errno.h>
 #include <linux/sched.h>
@@ -32,12 +31,10 @@
 #include <linux/notifier.h>
 #include <linux/kprobes.h>
 #include <linux/kdebug.h>
-#include <linux/tick.h>
 #include <linux/prctl.h>
 #include <linux/uaccess.h>
 #include <linux/io.h>
 #include <linux/ftrace.h>
-#include <linux/cpuidle.h>
 
 #include <asm/pgtable.h>
 #include <asm/system.h>
@@ -52,114 +49,10 @@
 #include <asm/idle.h>
 #include <asm/syscalls.h>
 #include <asm/debugreg.h>
-#include <asm/nmi.h>
 
 asmlinkage extern void ret_from_fork(void);
 
 DEFINE_PER_CPU(unsigned long, old_rsp);
-static DEFINE_PER_CPU(unsigned char, is_idle);
-
-static ATOMIC_NOTIFIER_HEAD(idle_notifier);
-
-void idle_notifier_register(struct notifier_block *n)
-{
-	atomic_notifier_chain_register(&idle_notifier, n);
-}
-EXPORT_SYMBOL_GPL(idle_notifier_register);
-
-void idle_notifier_unregister(struct notifier_block *n)
-{
-	atomic_notifier_chain_unregister(&idle_notifier, n);
-}
-EXPORT_SYMBOL_GPL(idle_notifier_unregister);
-
-void enter_idle(void)
-{
-	percpu_write(is_idle, 1);
-	atomic_notifier_call_chain(&idle_notifier, IDLE_START, NULL);
-}
-
-static void __exit_idle(void)
-{
-	if (x86_test_and_clear_bit_percpu(0, is_idle) == 0)
-		return;
-	atomic_notifier_call_chain(&idle_notifier, IDLE_END, NULL);
-}
-
-/* Called from interrupts to signify idle end */
-void exit_idle(void)
-{
-	/* idle loop has pid 0 */
-	if (current->pid)
-		return;
-	__exit_idle();
-}
-
-#ifndef CONFIG_SMP
-static inline void play_dead(void)
-{
-	BUG();
-}
-#endif
-
-/*
- * The idle thread. There's no useful work to be
- * done, so just try to conserve power and have a
- * low exit latency (ie sit in a loop waiting for
- * somebody to say that they'd like to reschedule)
- */
-void cpu_idle(void)
-{
-	current_thread_info()->status |= TS_POLLING;
-
-	/*
-	 * If we're the non-boot CPU, nothing set the stack canary up
-	 * for us.  CPU0 already has it initialized but no harm in
-	 * doing it again.  This is a good place for updating it, as
-	 * we wont ever return from this function (so the invalid
-	 * canaries already on the stack wont ever trigger).
-	 */
-	boot_init_stack_canary();
-
-	/* endless idle loop with no priority at all */
-	while (1) {
-		tick_nohz_idle_enter();
-		while (!need_resched()) {
-
-			rmb();
-
-			if (cpu_is_offline(smp_processor_id()))
-				play_dead();
-			/*
-			 * Idle routines should keep interrupts disabled
-			 * from here on, until they go to idle.
-			 * Otherwise, idle callbacks can misfire.
-			 */
-			local_touch_nmi();
-			local_irq_disable();
-			enter_idle();
-			/* Don't trace irqs off for idle */
-			stop_critical_timings();
-
-			/* enter_idle() needs rcu for notifiers */
-			rcu_idle_enter();
-
-			if (cpuidle_idle_call())
-				pm_idle();
-
-			rcu_idle_exit();
-			start_critical_timings();
-
-			/* In many cases the interrupt that ended idle
-			   has already called exit_idle. But some idle
-			   loops can be woken up without interrupt. */
-			__exit_idle();
-		}
-
-		tick_nohz_idle_exit();
-		schedule_preempt_disabled();
-	}
-}
 
 /* Prints also some state that isn't saved in the pt_regs */
 void __show_regs(struct pt_regs *regs, int all)

[PATCH] checkpatch.pl: Check for functions without a real prototype

[Richard Weinberger]

Functions like this one are evil:

void foo()
{
	...
}

Signed-off-by: Richard Weinberger <richard@nod.at>
CC: hpa@zytor.com
---
 scripts/checkpatch.pl |   13 +++++++++++++
 1 files changed, 13 insertions(+), 0 deletions(-)

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index a3b9782..acc5e0f 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -2304,6 +2304,19 @@ sub process {
 			      "open brace '{' following function declarations go on the next line\n" . $herecurr);
 		}
 
+		if ($line=~/$Type\s*$Ident\(\)/) {
+			ERROR("FUNCTION_NO_PROTOTYPE",
+"Function without a real prototype\n" . $herecurr .
+"Thou shalt not, in the language of C, under any circumstances, on the
+pain of death, declare or define a function with an empty set of
+parentheses, for though in the language of C++ it meaneth the same as
+(void), in C it meaneth (...) which is of meaningless as there be no
+anchor argument by which the types of the varadic arguments can be
+expressed, and which misleadeth the compiler into allowing unsavory code
+and in some cases generate really ugly stuff for varadic handling.
+	-hpa\n");
+		}
+
 # open braces for enum, union and struct go on the same line.
 		if ($line =~ /^.\s*{/ &&
 		    $prevline =~ /^.\s*(?:typedef\s+)?(enum|union|struct)(?:\s+$Ident)?\s*$/) {
-- 
1.7.7.3

Re: [PATCH] checkpatch.pl: Check for functions without a real prototype

[Joe Perches]

On Sat, 2012-03-17 at 00:04 +0100, Richard Weinberger wrote:
> Functions like this one are evil:
> void foo()
> {
> 	...
> }
[]
> diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
[]
> @@ -2304,6 +2304,19 @@ sub process {
[]
> +		if ($line=~/$Type\s*$Ident\(\)/) {

Perhaps this should be:
		if ($line =~ /(\b$Type\s+$Ident)\s*\(\s*\)/) {

> +			ERROR("FUNCTION_NO_PROTOTYPE",
> +"Function without a real prototype\n" . $herecurr .

Sensible, but maybe:
"Bad function definition - $1() should probably be $1(void)\n"

> +"Thou shalt not, in the language of C, under any circumstances, on the
> +pain of death, declare or define a function with an empty set of
> +parentheses, for though in the language of C++ it meaneth the same as
> +(void), in C it meaneth (...) which is of meaningless as there be no
> +anchor argument by which the types of the varadic arguments can be
> +expressed, and which misleadeth the compiler into allowing unsavory code
> +and in some cases generate really ugly stuff for varadic handling.
> +	-hpa\n");

Humorous once, painful in twice, annoying after.

cheers,  Joe

Re: [PATCH] checkpatch.pl: Check for functions without a real prototype

[Richard Weinberger]

[-- Attachment #1: Type: text/plain, Size: 999 bytes --]

Am 17.03.2012 00:31, schrieb Joe Perches:
> Perhaps this should be:
> 		if ($line =~ /(\b$Type\s+$Ident)\s*\(\s*\)/) {

Makes sense.

>> +			ERROR("FUNCTION_NO_PROTOTYPE",
>> +"Function without a real prototype\n" . $herecurr .
> 
> Sensible, but maybe:
> "Bad function definition - $1() should probably be $1(void)\n"

Too.

>> +"Thou shalt not, in the language of C, under any circumstances, on the
>> +pain of death, declare or define a function with an empty set of
>> +parentheses, for though in the language of C++ it meaneth the same as
>> +(void), in C it meaneth (...) which is of meaningless as there be no
>> +anchor argument by which the types of the varadic arguments can be
>> +expressed, and which misleadeth the compiler into allowing unsavory code
>> +and in some cases generate really ugly stuff for varadic handling.
>> +	-hpa\n");
> 
> Humorous once, painful in twice, annoying after.
> 

It has to be annoying and painful. :-)

Thanks,
//richard


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