x86-64: Move oldrsp from PDA to per-cpu.

tj: * in asm-offsets_64.c, pda.h inclusion shouldn't be removed as pda
      is still referenced in the file
    * s/oldrsp/old_rsp/

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

1 files changed, 5 insertions, 3 deletions

diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index 6c5f57602108..480128918926 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -60,6 +60,8 @@ asmlinkage extern void ret_from_fork(void);
 DEFINE_PER_CPU(struct task_struct *, current_task) = &init_task;
 EXPORT_PER_CPU_SYMBOL(current_task);
 
+DEFINE_PER_CPU(unsigned long, old_rsp);
+
 unsigned long kernel_thread_flags = CLONE_VM | CLONE_UNTRACED;
 
 static ATOMIC_NOTIFIER_HEAD(idle_notifier);
@@ -395,7 +397,7 @@ start_thread(struct pt_regs *regs, unsigned long new_ip, unsigned long new_sp)
         load_gs_index(0);
         regs->ip                = new_ip;
         regs->sp                = new_sp;
-        write_pda(oldrsp, new_sp);
+        percpu_write(old_rsp, new_sp);
         regs->cs                = __USER_CS;
         regs->ss                = __USER_DS;
         regs->flags             = 0x200;
@@ -616,8 +618,8 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
         /*
          * Switch the PDA and FPU contexts.
          */
-        prev->usersp = read_pda(oldrsp);
-        write_pda(oldrsp, next->usersp);
+        prev->usersp = percpu_read(old_rsp);
+        percpu_write(old_rsp, next->usersp);
         percpu_write(current_task, next_p);
 
         percpu_write(kernel_stack,