1 files changed, 26 insertions, 17 deletions

diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index 416fb9282f4f..c422eebb0c58 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -16,6 +16,7 @@
 
 #include <stdarg.h>
 
+#include <linux/stackprotector.h>
 #include <linux/cpu.h>
 #include <linux/errno.h>
 #include <linux/sched.h>
@@ -46,7 +47,6 @@
 #include <asm/processor.h>
 #include <asm/i387.h>
 #include <asm/mmu_context.h>
-#include <asm/pda.h>
 #include <asm/prctl.h>
 #include <asm/desc.h>
 #include <asm/proto.h>
@@ -57,6 +57,12 @@
 
 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);
+static DEFINE_PER_CPU(unsigned char, is_idle);
+
 unsigned long kernel_thread_flags = CLONE_VM | CLONE_UNTRACED;
 
 static ATOMIC_NOTIFIER_HEAD(idle_notifier);
@@ -75,13 +81,13 @@ EXPORT_SYMBOL_GPL(idle_notifier_unregister);
 
 void enter_idle(void)
 {
-        write_pda(isidle, 1);
+        percpu_write(is_idle, 1);
         atomic_notifier_call_chain(&idle_notifier, IDLE_START, NULL);
 }
 
 static void __exit_idle(void)
 {
-        if (test_and_clear_bit_pda(0, isidle) == 0)
+        if (x86_test_and_clear_bit_percpu(0, is_idle) == 0)
                 return;
         atomic_notifier_call_chain(&idle_notifier, IDLE_END, NULL);
 }
@@ -111,6 +117,17 @@ static inline void play_dead(void)
 void cpu_idle(void)
 {
         current_thread_info()->status |= TS_POLLING;
+
+        /*
+         * If we're the non-boot CPU, nothing set the PDA stack
+         * canary up for us - and if we are the boot CPU we have
+         * a 0 stack canary. This is a good place for updating
+         * it, as we wont ever return from this function (so the
+         * invalid canaries already on the stack wont ever
+         * trigger):
+         */
+        boot_init_stack_canary();
+
         /* endless idle loop with no priority at all */
         while (1) {
                 tick_nohz_stop_sched_tick(1);
@@ -392,7 +409,7 @@ 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;
@@ -613,21 +630,13 @@ __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);
-        write_pda(pcurrent, next_p);
+        prev->usersp = percpu_read(old_rsp);
+        percpu_write(old_rsp, next->usersp);
+        percpu_write(current_task, next_p);
 
-        write_pda(kernelstack,
+        percpu_write(kernel_stack,
                   (unsigned long)task_stack_page(next_p) +
-                  THREAD_SIZE - PDA_STACKOFFSET);
-#ifdef CONFIG_CC_STACKPROTECTOR
-        write_pda(stack_canary, next_p->stack_canary);
-        /*
-         * 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
+                  THREAD_SIZE - KERNEL_STACK_OFFSET);
 
         /*
          * Now maybe reload the debug registers and handle I/O bitmaps