x86-64: Move current task from PDA to per-cpu and consolidate with 32-bit.

Signed-off-by: Brian Gerst <brgerst@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

5 files changed, 7 insertions, 9 deletions

diff --git a/arch/x86/kernel/asm-offsets_64.c b/arch/x86/kernel/asm-offsets_64.c
index cae6697c0991..4f7a210e1e58 100644
--- a/arch/x86/kernel/asm-offsets_64.c
+++ b/arch/x86/kernel/asm-offsets_64.c
@@ -51,7 +51,6 @@ int main(void)
 #define ENTRY(entry) DEFINE(pda_ ## entry, offsetof(struct x8664_pda, entry))
         ENTRY(kernelstack); 
         ENTRY(oldrsp); 
-        ENTRY(pcurrent); 
         ENTRY(irqcount);
         DEFINE(pda_size, sizeof(struct x8664_pda));
         BLANK();
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index 4221e920886d..b50e38d16888 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -903,10 +903,7 @@ void __cpuinit pda_init(int cpu)
         pda->kernelstack = (unsigned long)stack_thread_info() -
                                  PDA_STACKOFFSET + THREAD_SIZE;
 
-        if (cpu == 0) {
-                /* others are initialized in smpboot.c */
-                pda->pcurrent = &init_task;
-        } else {
+        if (cpu != 0) {
                 if (pda->nodenumber == 0 && cpu_to_node(cpu) != NUMA_NO_NODE)
                         pda->nodenumber = cpu_to_node(cpu);
         }
diff --git a/arch/x86/kernel/dumpstack_64.c b/arch/x86/kernel/dumpstack_64.c
index 28e26a4315df..d35db5993fd6 100644
--- a/arch/x86/kernel/dumpstack_64.c
+++ b/arch/x86/kernel/dumpstack_64.c
@@ -242,7 +242,7 @@ void show_registers(struct pt_regs *regs)
         int i;
         unsigned long sp;
         const int cpu = smp_processor_id();
-        struct task_struct *cur = cpu_pda(cpu)->pcurrent;
+        struct task_struct *cur = current;
 
         sp = regs->sp;
         printk("CPU %d ", cpu);
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index 416fb9282f4f..e00c31a4b3c0 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -57,6 +57,9 @@
 
 asmlinkage extern void ret_from_fork(void);
 
+DEFINE_PER_CPU(struct task_struct *, current_task) = &init_task;
+EXPORT_PER_CPU_SYMBOL(current_task);
+
 unsigned long kernel_thread_flags = CLONE_VM | CLONE_UNTRACED;
 
 static ATOMIC_NOTIFIER_HEAD(idle_notifier);
@@ -615,7 +618,7 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
          */
         prev->usersp = read_pda(oldrsp);
         write_pda(oldrsp, next->usersp);
-        write_pda(pcurrent, next_p);
+        percpu_write(current_task, next_p);
 
         write_pda(kernelstack,
                   (unsigned long)task_stack_page(next_p) +
diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index 2f0e0f1090f6..5854be0fb804 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -790,13 +790,12 @@ static int __cpuinit do_boot_cpu(int apicid, int cpu)
 
         set_idle_for_cpu(cpu, c_idle.idle);
 do_rest:
-#ifdef CONFIG_X86_32
         per_cpu(current_task, cpu) = c_idle.idle;
+#ifdef CONFIG_X86_32
         init_gdt(cpu);
         /* Stack for startup_32 can be just as for start_secondary onwards */
         irq_ctx_init(cpu);
 #else
-        cpu_pda(cpu)->pcurrent = c_idle.idle;
         clear_tsk_thread_flag(c_idle.idle, TIF_FORK);
         initial_gs = per_cpu_offset(cpu);
 #endif