x86/entry: Remove unused 'kernel_stack' per-cpu variable

Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
Acked-by: Andy Lutomirski <luto@kernel.org>
Cc: Alexei Starovoitov <ast@plumgrid.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Drewry <wad@chromium.org>
Link: http://lkml.kernel.org/r/1429889495-27850-2-git-send-email-dvlasenk@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thread_info.h
index d656a36..4722889 100644 (file)
--- a/arch/x86/include/asm/thread_info.h
+++ b/arch/x86/include/asm/thread_info.h
@@ -177,8 +177,6 @@ struct thread_info {
  */
 #ifndef __ASSEMBLY__
 
-DECLARE_PER_CPU(unsigned long, kernel_stack);
-
 static inline struct thread_info *current_thread_info(void)
 {
        return (struct thread_info *)(current_top_of_stack() - THREAD_SIZE);

diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index a62cf04..6bec0b5 100644 (file)
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -1155,10 +1155,6 @@ static __init int setup_disablecpuid(char *arg)
 }
 __setup("clearcpuid=", setup_disablecpuid);
 
-DEFINE_PER_CPU(unsigned long, kernel_stack) =
-       (unsigned long)&init_thread_union + THREAD_SIZE;
-EXPORT_PER_CPU_SYMBOL(kernel_stack);
-
 #ifdef CONFIG_X86_64
 struct desc_ptr idt_descr = { NR_VECTORS * 16 - 1, (unsigned long) idt_table };
 struct desc_ptr debug_idt_descr = { NR_VECTORS * 16 - 1,

diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c
index 8ed2106..a99900c 100644 (file)
--- a/arch/x86/kernel/process_32.c
+++ b/arch/x86/kernel/process_32.c
@@ -302,13 +302,10 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
        arch_end_context_switch(next_p);
 
        /*
-        * Reload esp0, kernel_stack, and current_top_of_stack.  This changes
+        * Reload esp0 and cpu_current_top_of_stack.  This changes
         * current_thread_info().
         */
        load_sp0(tss, next);
-       this_cpu_write(kernel_stack,
-                      (unsigned long)task_stack_page(next_p) +
-                      THREAD_SIZE);
        this_cpu_write(cpu_current_top_of_stack,
                       (unsigned long)task_stack_page(next_p) +
                       THREAD_SIZE);

diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index ddfdbf7..8213450 100644 (file)
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -409,9 +409,6 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
        /* Reload esp0 and ss1.  This changes current_thread_info(). */
        load_sp0(tss, next);
 
-       this_cpu_write(kernel_stack,
-               (unsigned long)task_stack_page(next_p) + THREAD_SIZE);
-
        /*
         * Now maybe reload the debug registers and handle I/O bitmaps
         */

diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index 50e547e..023cccf 100644 (file)
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -792,8 +792,6 @@ void common_cpu_up(unsigned int cpu, struct task_struct *idle)
        clear_tsk_thread_flag(idle, TIF_FORK);
        initial_gs = per_cpu_offset(cpu);
 #endif
-       per_cpu(kernel_stack, cpu) =
-               (unsigned long)task_stack_page(idle) + THREAD_SIZE;
 }
 
 /*