1 files changed, 5 insertions, 25 deletions

diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index 9b9fe4a85c87..cfa5c90c01db 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -286,6 +286,7 @@ int copy_thread(unsigned long clone_flags, unsigned long sp,
 
         set_tsk_thread_flag(p, TIF_FORK);
 
+        p->fpu_counter = 0;
         p->thread.io_bitmap_ptr = NULL;
 
         savesegment(gs, p->thread.gsindex);
@@ -386,18 +387,9 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
         int cpu = smp_processor_id();
         struct tss_struct *tss = &per_cpu(init_tss, cpu);
         unsigned fsindex, gsindex;
-        bool preload_fpu;
+        fpu_switch_t fpu;
 
-        /*
-         * If the task has used fpu the last 5 timeslices, just do a full
-         * restore of the math state immediately to avoid the trap; the
-         * chances of needing FPU soon are obviously high now
-         */
-        preload_fpu = tsk_used_math(next_p) && next_p->fpu_counter > 5;
-
-        /* we're going to use this soon, after a few expensive things */
-        if (preload_fpu)
-                prefetch(next->fpu.state);
+        fpu = switch_fpu_prepare(prev_p, next_p, cpu);
 
         /*
          * Reload esp0, LDT and the page table pointer:
@@ -427,13 +419,6 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
 
         load_TLS(next, cpu);
 
-        /* Must be after DS reload */
-        __unlazy_fpu(prev_p);
-
-        /* Make sure cpu is ready for new context */
-        if (preload_fpu)
-                clts();
-
         /*
          * Leave lazy mode, flushing any hypercalls made here.
          * This must be done before restoring TLS segments so
@@ -474,6 +459,8 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
                 wrmsrl(MSR_KERNEL_GS_BASE, next->gs);
         prev->gsindex = gsindex;
 
+        switch_fpu_finish(next_p, fpu);
+
         /*
          * Switch the PDA and FPU contexts.
          */
@@ -492,13 +479,6 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
                      task_thread_info(prev_p)->flags & _TIF_WORK_CTXSW_PREV))
                 __switch_to_xtra(prev_p, next_p, tss);
 
-        /*
-         * Preload the FPU context, now that we've determined that the
-         * task is likely to be using it. 
-         */
-        if (preload_fpu)
-                __math_state_restore();
-
         return prev_p;
 }