[v2,2/4] exit_thread: remove empty bodies

diff --git a/arch/Kconfig b/arch/Kconfig
index 81869a5e7e17..0f298f9123dc 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -517,6 +517,11 @@  config HAVE_ARCH_MMAP_RND_BITS
 	  - ARCH_MMAP_RND_BITS_MIN
 	  - ARCH_MMAP_RND_BITS_MAX
 
+config HAVE_EXIT_THREAD
+	bool
+	help
+	  An architecture implements exit_thread.
+
 config ARCH_MMAP_RND_BITS_MIN
 	int
 
diff --git a/arch/alpha/kernel/process.c b/arch/alpha/kernel/process.c
index 84d13263ce46..b483156698d5 100644
--- a/arch/alpha/kernel/process.c
+++ b/arch/alpha/kernel/process.c
@@ -210,14 +210,6 @@  start_thread(struct pt_regs * regs, unsigned long pc, unsigned long sp)
 }
 EXPORT_SYMBOL(start_thread);
 
-/*
- * Free current thread data structures etc..
- */
-void
-exit_thread(void)
-{
-}
-
 void
 flush_thread(void)
 {
diff --git a/arch/arc/kernel/process.c b/arch/arc/kernel/process.c
index a3f750e76b68..b5db9e7fd649 100644
--- a/arch/arc/kernel/process.c
+++ b/arch/arc/kernel/process.c
@@ -183,13 +183,6 @@  void flush_thread(void)
 {
 }
 
-/*
- * Free any architecture-specific thread data structures, etc.
- */
-void exit_thread(void)
-{
-}
-
 int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu)
 {
 	return 0;
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index cdfa6c2b7626..0846026c84de 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -50,6 +50,7 @@  config ARM
 	select HAVE_DMA_CONTIGUOUS if MMU
 	select HAVE_DYNAMIC_FTRACE if (!XIP_KERNEL) && !CPU_ENDIAN_BE32 && MMU
 	select HAVE_EFFICIENT_UNALIGNED_ACCESS if (CPU_V6 || CPU_V6K || CPU_V7) && MMU
+	select HAVE_EXIT_THREAD
 	select HAVE_FTRACE_MCOUNT_RECORD if (!XIP_KERNEL)
 	select HAVE_FUNCTION_GRAPH_TRACER if (!THUMB2_KERNEL)
 	select HAVE_FUNCTION_TRACER if (!XIP_KERNEL)
diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c
index 80624829db61..5655f756e4f2 100644
--- a/arch/arm64/kernel/process.c
+++ b/arch/arm64/kernel/process.c
@@ -200,13 +200,6 @@  void show_regs(struct pt_regs * regs)
 	__show_regs(regs);
 }
 
-/*
- * Free current thread data structures etc..
- */
-void exit_thread(void)
-{
-}
-
 static void tls_thread_flush(void)
 {
 	asm ("msr tpidr_el0, xzr");
diff --git a/arch/avr32/Kconfig b/arch/avr32/Kconfig
index b6878eb64884..37d9c02be634 100644
--- a/arch/avr32/Kconfig
+++ b/arch/avr32/Kconfig
@@ -4,6 +4,7 @@  config AVR32
 	# that we usually don't need on AVR32.
 	select EXPERT
 	select HAVE_CLK
+	select HAVE_EXIT_THREAD
 	select HAVE_OPROFILE
 	select HAVE_KPROBES
 	select VIRT_TO_BUS
diff --git a/arch/blackfin/include/asm/processor.h b/arch/blackfin/include/asm/processor.h
index 7acd46653df3..0c265aba94ad 100644
--- a/arch/blackfin/include/asm/processor.h
+++ b/arch/blackfin/include/asm/processor.h
@@ -76,13 +76,6 @@  static inline void release_thread(struct task_struct *dead_task)
 }
 
 /*
- * Free current thread data structures etc..
- */
-static inline void exit_thread(void)
-{
-}
-
-/*
  * Return saved PC of a blocked thread.
  */
 #define thread_saved_pc(tsk)	(tsk->thread.pc)
diff --git a/arch/c6x/kernel/process.c b/arch/c6x/kernel/process.c
index 3ae9f5a166a0..0ee7686a78f3 100644
--- a/arch/c6x/kernel/process.c
+++ b/arch/c6x/kernel/process.c
@@ -82,10 +82,6 @@  void flush_thread(void)
 {
 }
 
-void exit_thread(void)
-{
-}
-
 /*
  * Do necessary setup to start up a newly executed thread.
  */
diff --git a/arch/cris/Kconfig b/arch/cris/Kconfig
index e086f9e93728..10a5ccb85cd6 100644
--- a/arch/cris/Kconfig
+++ b/arch/cris/Kconfig
@@ -62,6 +62,7 @@  config CRIS
 	select OLD_SIGSUSPEND
 	select OLD_SIGACTION
 	select ARCH_REQUIRE_GPIOLIB
+	select HAVE_EXIT_THREAD if ETRAX_ARCH_V32
 	select IRQ_DOMAIN if ETRAX_ARCH_V32
 	select OF if ETRAX_ARCH_V32
 	select OF_EARLY_FLATTREE if ETRAX_ARCH_V32
diff --git a/arch/cris/arch-v10/kernel/process.c b/arch/cris/arch-v10/kernel/process.c
index 02b783457be0..96e5afef6b47 100644
--- a/arch/cris/arch-v10/kernel/process.c
+++ b/arch/cris/arch-v10/kernel/process.c
@@ -35,15 +35,6 @@  void default_idle(void)
 	local_irq_enable();
 }
 
-/*
- * Free current thread data structures etc..
- */
-
-void exit_thread(void)
-{
-	/* Nothing needs to be done.  */
-}
-
 /* if the watchdog is enabled, we can simply disable interrupts and go
  * into an eternal loop, and the watchdog will reset the CPU after 0.1s
  * if on the other hand the watchdog wasn't enabled, we just enable it and wait
diff --git a/arch/frv/include/asm/processor.h b/arch/frv/include/asm/processor.h
index ae8d423e79d9..73f0a79ad8e6 100644
--- a/arch/frv/include/asm/processor.h
+++ b/arch/frv/include/asm/processor.h
@@ -97,13 +97,6 @@  extern asmlinkage void *restore_user_regs(const struct user_context *target, ...
 #define forget_segments()		do { } while (0)
 
 /*
- * Free current thread data structures etc..
- */
-static inline void exit_thread(void)
-{
-}
-
-/*
  * Return saved PC of a blocked thread.
  */
 extern unsigned long thread_saved_pc(struct task_struct *tsk);
diff --git a/arch/h8300/include/asm/processor.h b/arch/h8300/include/asm/processor.h
index 54e3fd83c336..111df7397ac7 100644
--- a/arch/h8300/include/asm/processor.h
+++ b/arch/h8300/include/asm/processor.h
@@ -111,13 +111,6 @@  static inline void release_thread(struct task_struct *dead_task)
 }
 
 /*
- * Free current thread data structures etc..
- */
-static inline void exit_thread(void)
-{
-}
-
-/*
  * Return saved PC of a blocked thread.
  */
 unsigned long thread_saved_pc(struct task_struct *tsk);
diff --git a/arch/hexagon/kernel/process.c b/arch/hexagon/kernel/process.c
index a9ebd471823a..d9edfd3fc52a 100644
--- a/arch/hexagon/kernel/process.c
+++ b/arch/hexagon/kernel/process.c
@@ -137,13 +137,6 @@  void release_thread(struct task_struct *dead_task)
 }
 
 /*
- * Free any architecture-specific thread data structures, etc.
- */
-void exit_thread(void)
-{
-}
-
-/*
  * Some archs flush debug and FPU info here
  */
 void flush_thread(void)
diff --git a/arch/ia64/Kconfig b/arch/ia64/Kconfig
index b534ebab36ea..f80758cb7157 100644
--- a/arch/ia64/Kconfig
+++ b/arch/ia64/Kconfig
@@ -18,6 +18,7 @@  config IA64
 	select ACPI_SYSTEM_POWER_STATES_SUPPORT if ACPI
 	select ARCH_MIGHT_HAVE_ACPI_PDC if ACPI
 	select HAVE_UNSTABLE_SCHED_CLOCK
+	select HAVE_EXIT_THREAD
 	select HAVE_IDE
 	select HAVE_OPROFILE
 	select HAVE_KPROBES
diff --git a/arch/m32r/kernel/process.c b/arch/m32r/kernel/process.c
index e69221d581d5..a88b1f01e91f 100644
--- a/arch/m32r/kernel/process.c
+++ b/arch/m32r/kernel/process.c
@@ -101,15 +101,6 @@  void show_regs(struct pt_regs * regs)
 #endif
 }
 
-/*
- * Free current thread data structures etc..
- */
-void exit_thread(void)
-{
-	/* Nothing to do. */
-	DPRINTK("pid = %d\n", current->pid);
-}
-
 void flush_thread(void)
 {
 	DPRINTK("pid = %d\n", current->pid);
diff --git a/arch/m68k/include/asm/processor.h b/arch/m68k/include/asm/processor.h
index 20dda1d4b860..a6ce2ec8d693 100644
--- a/arch/m68k/include/asm/processor.h
+++ b/arch/m68k/include/asm/processor.h
@@ -153,13 +153,6 @@  static inline void release_thread(struct task_struct *dead_task)
 {
 }
 
-/*
- * Free current thread data structures etc..
- */
-static inline void exit_thread(void)
-{
-}
-
 extern unsigned long thread_saved_pc(struct task_struct *tsk);
 
 unsigned long get_wchan(struct task_struct *p);
diff --git a/arch/metag/Kconfig b/arch/metag/Kconfig
index a0fa88da3e31..e47a08d72819 100644
--- a/arch/metag/Kconfig
+++ b/arch/metag/Kconfig
@@ -11,6 +11,7 @@  config METAG
 	select HAVE_DEBUG_KMEMLEAK
 	select HAVE_DEBUG_STACKOVERFLOW
 	select HAVE_DYNAMIC_FTRACE
+	select HAVE_EXIT_THREAD
 	select HAVE_FTRACE_MCOUNT_RECORD
 	select HAVE_FUNCTION_TRACER
 	select HAVE_KERNEL_BZIP2
diff --git a/arch/metag/include/asm/processor.h b/arch/metag/include/asm/processor.h
index 0838ca699764..a0333ebcac35 100644
--- a/arch/metag/include/asm/processor.h
+++ b/arch/metag/include/asm/processor.h
@@ -134,8 +134,6 @@  static inline void release_thread(struct task_struct *dead_task)
 #define copy_segments(tsk, mm)		do { } while (0)
 #define release_segments(mm)		do { } while (0)
 
-extern void exit_thread(void);
-
 /*
  * Return saved PC of a blocked thread.
  */
diff --git a/arch/microblaze/include/asm/processor.h b/arch/microblaze/include/asm/processor.h
index 497a988d79c2..c38d0dd91134 100644
--- a/arch/microblaze/include/asm/processor.h
+++ b/arch/microblaze/include/asm/processor.h
@@ -70,11 +70,6 @@  static inline void release_thread(struct task_struct *dead_task)
 {
 }
 
-/* Free all resources held by a thread. */
-static inline void exit_thread(void)
-{
-}
-
 extern unsigned long thread_saved_pc(struct task_struct *t);
 
 extern unsigned long get_wchan(struct task_struct *p);
@@ -127,11 +122,6 @@  static inline void release_thread(struct task_struct *dead_task)
 {
 }
 
-/* Free current thread data structures etc.  */
-static inline void exit_thread(void)
-{
-}
-
 /* Return saved (kernel) PC of a blocked thread.  */
 #  define thread_saved_pc(tsk)	\
 	((tsk)->thread.regs ? (tsk)->thread.regs->r15 : 0)
diff --git a/arch/mips/include/asm/processor.h b/arch/mips/include/asm/processor.h
index 06469df2b638..cfa15bad43af 100644
--- a/arch/mips/include/asm/processor.h
+++ b/arch/mips/include/asm/processor.h
@@ -359,10 +359,6 @@  static inline void flush_thread(void)
 {
 }
 
-static inline void exit_thread(void)
-{
-}
-
 unsigned long get_wchan(struct task_struct *p);
 
 #define __KSTK_TOS(tsk) ((unsigned long)task_stack_page(tsk) + \
diff --git a/arch/mn10300/Kconfig b/arch/mn10300/Kconfig
index 06ddb5501ab1..9627e81a6cbb 100644
--- a/arch/mn10300/Kconfig
+++ b/arch/mn10300/Kconfig
@@ -1,5 +1,6 @@ 
 config MN10300
 	def_bool y
+	select HAVE_EXIT_THREAD
 	select HAVE_OPROFILE
 	select HAVE_UID16
 	select GENERIC_IRQ_SHOW
diff --git a/arch/nios2/include/asm/processor.h b/arch/nios2/include/asm/processor.h
index c2ba45c159c7..1c953f0cadbf 100644
--- a/arch/nios2/include/asm/processor.h
+++ b/arch/nios2/include/asm/processor.h
@@ -75,11 +75,6 @@  static inline void release_thread(struct task_struct *dead_task)
 {
 }
 
-/* Free current thread data structures etc.. */
-static inline void exit_thread(void)
-{
-}
-
 /* Return saved PC of a blocked thread. */
 #define thread_saved_pc(tsk)	((tsk)->thread.kregs->ea)
 
diff --git a/arch/openrisc/include/asm/processor.h b/arch/openrisc/include/asm/processor.h
index 4d235e3d2534..70334c9f7d24 100644
--- a/arch/openrisc/include/asm/processor.h
+++ b/arch/openrisc/include/asm/processor.h
@@ -85,15 +85,6 @@  void release_thread(struct task_struct *);
 unsigned long get_wchan(struct task_struct *p);
 
 /*
- * Free current thread data structures etc..
- */
-
-extern inline void exit_thread(void)
-{
-	/* Nothing needs to be done.  */
-}
-
-/*
  * Return saved PC of a blocked thread. For now, this is the "user" PC
  */
 extern unsigned long thread_saved_pc(struct task_struct *t);
diff --git a/arch/parisc/kernel/process.c b/arch/parisc/kernel/process.c
index 809905a811ed..40639439d8b3 100644
--- a/arch/parisc/kernel/process.c
+++ b/arch/parisc/kernel/process.c
@@ -144,13 +144,6 @@  void machine_power_off(void)
 void (*pm_power_off)(void) = machine_power_off;
 EXPORT_SYMBOL(pm_power_off);
 
-/*
- * Free current thread data structures etc..
- */
-void exit_thread(void)
-{
-}
-
 void flush_thread(void)
 {
 	/* Only needs to handle fpu stuff or perf monitors.
diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index 612df305886b..e323020d91dd 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -1326,10 +1326,6 @@  void show_regs(struct pt_regs * regs)
 		show_instructions(regs);
 }
 
-void exit_thread(void)
-{
-}
-
 void flush_thread(void)
 {
 #ifdef CONFIG_HAVE_HW_BREAKPOINT
diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index 43b25835325f..37941df616d9 100644
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -130,6 +130,7 @@  config S390
 	select HAVE_DMA_API_DEBUG
 	select HAVE_DYNAMIC_FTRACE
 	select HAVE_DYNAMIC_FTRACE_WITH_REGS
+	select HAVE_EXIT_THREAD
 	select HAVE_FTRACE_MCOUNT_RECORD
 	select HAVE_FUNCTION_GRAPH_TRACER
 	select HAVE_FUNCTION_TRACER
diff --git a/arch/score/kernel/process.c b/arch/score/kernel/process.c
index a1519ad3d49d..aae9480706c2 100644
--- a/arch/score/kernel/process.c
+++ b/arch/score/kernel/process.c
@@ -56,8 +56,6 @@  void start_thread(struct pt_regs *regs, unsigned long pc, unsigned long sp)
 	regs->regs[0] = sp;
 }
 
-void exit_thread(void) {}
-
 /*
  * When a process does an "exec", machine state like FPU and debug
  * registers need to be reset.  This is a hook function for that.
diff --git a/arch/sh/Kconfig b/arch/sh/Kconfig
index 7ed20fc3fc81..cb93af8f8017 100644
--- a/arch/sh/Kconfig
+++ b/arch/sh/Kconfig
@@ -71,6 +71,7 @@  config SUPERH32
 
 config SUPERH64
 	def_bool ARCH = "sh64"
+	select HAVE_EXIT_THREAD
 	select KALLSYMS
 
 config ARCH_DEFCONFIG
diff --git a/arch/sh/kernel/process_32.c b/arch/sh/kernel/process_32.c
index 2885fc9d9dcd..ee12e9451874 100644
--- a/arch/sh/kernel/process_32.c
+++ b/arch/sh/kernel/process_32.c
@@ -76,13 +76,6 @@  void start_thread(struct pt_regs *regs, unsigned long new_pc,
 }
 EXPORT_SYMBOL(start_thread);
 
-/*
- * Free current thread data structures etc..
- */
-void exit_thread(void)
-{
-}
-
 void flush_thread(void)
 {
 	struct task_struct *tsk = current;
diff --git a/arch/sparc/Kconfig b/arch/sparc/Kconfig
index 57ffaf285c2f..b66aea06e9c9 100644
--- a/arch/sparc/Kconfig
+++ b/arch/sparc/Kconfig
@@ -20,6 +20,7 @@  config SPARC
 	select HAVE_OPROFILE
 	select HAVE_ARCH_KGDB if !SMP || SPARC64
 	select HAVE_ARCH_TRACEHOOK
+	select HAVE_EXIT_THREAD
 	select SYSCTL_EXCEPTION_TRACE
 	select ARCH_WANT_OPTIONAL_GPIOLIB
 	select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
diff --git a/arch/tile/Kconfig b/arch/tile/Kconfig
index 81719302b056..174746225577 100644
--- a/arch/tile/Kconfig
+++ b/arch/tile/Kconfig
@@ -3,6 +3,7 @@ 
 
 config TILE
 	def_bool y
+	select HAVE_EXIT_THREAD
 	select HAVE_PERF_EVENTS
 	select USE_PMC if PERF_EVENTS
 	select HAVE_DMA_API_DEBUG
diff --git a/arch/um/kernel/process.c b/arch/um/kernel/process.c
index 48af59aae129..0b04711f1f18 100644
--- a/arch/um/kernel/process.c
+++ b/arch/um/kernel/process.c
@@ -103,10 +103,6 @@  void interrupt_end(void)
 		tracehook_notify_resume(regs);
 }
 
-void exit_thread(void)
-{
-}
-
 int get_current_pid(void)
 {
 	return task_pid_nr(current);
diff --git a/arch/unicore32/kernel/process.c b/arch/unicore32/kernel/process.c
index b008e9961465..00299c927852 100644
--- a/arch/unicore32/kernel/process.c
+++ b/arch/unicore32/kernel/process.c
@@ -201,13 +201,6 @@  void show_regs(struct pt_regs *regs)
 	__backtrace();
 }
 
-/*
- * Free current thread data structures etc..
- */
-void exit_thread(void)
-{
-}
-
 void flush_thread(void)
 {
 	struct thread_info *thread = current_thread_info();
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 6bc6f9832d67..8f6196084eac 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -105,6 +105,7 @@  config X86
 	select HAVE_DYNAMIC_FTRACE
 	select HAVE_DYNAMIC_FTRACE_WITH_REGS
 	select HAVE_EFFICIENT_UNALIGNED_ACCESS
+	select HAVE_EXIT_THREAD
 	select HAVE_FENTRY			if X86_64
 	select HAVE_FTRACE_MCOUNT_RECORD
 	select HAVE_FUNCTION_GRAPH_FP_TEST
diff --git a/arch/xtensa/Kconfig b/arch/xtensa/Kconfig
index e832d3e9835e..c6b2ee78b617 100644
--- a/arch/xtensa/Kconfig
+++ b/arch/xtensa/Kconfig
@@ -15,6 +15,7 @@  config XTENSA
 	select GENERIC_PCI_IOMAP
 	select GENERIC_SCHED_CLOCK
 	select HAVE_DMA_API_DEBUG
+	select HAVE_EXIT_THREAD
 	select HAVE_FUNCTION_TRACER
 	select HAVE_FUTEX_CMPXCHG if !MMU
 	select HAVE_HW_BREAKPOINT if PERF_EVENTS
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 362c0e20ebbb..de5370802828 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -2646,7 +2646,14 @@  static inline int copy_thread_tls(
 }
 #endif
 extern void flush_thread(void);
+
+#ifdef CONFIG_HAVE_EXIT_THREAD
 extern void exit_thread(void);
+#else
+static inline void exit_thread(void)
+{
+}
+#endif
 
 extern void exit_files(struct task_struct *);
 extern void __cleanup_sighand(struct sighand_struct *);