x86: cleanup stack protector

Impact: cleanup

Make the following cleanups.

* remove duplicate comment from boot_init_stack_canary() which fits
  better in the other place - cpu_idle().

* move stack_canary offset check from __switch_to() to
  boot_init_stack_canary().

Signed-off-by: Tejun Heo <tj@kernel.org>

1 files changed, 0 insertions, 7 deletions

diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index aa89eabf09e0..088bc9a0f82c 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -638,13 +638,6 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
         percpu_write(kernel_stack,
                   (unsigned long)task_stack_page(next_p) +
                   THREAD_SIZE - KERNEL_STACK_OFFSET);
-#ifdef CONFIG_CC_STACKPROTECTOR
-        /*
-         * Build time only check to make sure the stack_canary is at
-         * offset 40 in the pda; this is a gcc ABI requirement
-         */
-        BUILD_BUG_ON(offsetof(struct x8664_pda, stack_canary) != 40);
-#endif
 
         /*
          * Now maybe reload the debug registers and handle I/O bitmaps