Merge branch 'x86-cleanups-for-linus' of git://git.kernel.org/pub/scm/linux/kernel...

[linux-2.6-block.git] / arch / x86 / kernel / process_32.c

diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c
index 59f4524984afacd10b456dcdca4abbc2237d7ecb..540140284f60ec62fc1a623ec2f3ee47249a1748 100644 (file)
--- a/arch/x86/kernel/process_32.c
+++ b/arch/x86/kernel/process_32.c
@@ -58,12 +58,10 @@
 #include <asm/idle.h>
 #include <asm/syscalls.h>
 #include <asm/ds.h>
+#include <asm/debugreg.h>
 
 asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
 
-DEFINE_PER_CPU(struct task_struct *, current_task) = &init_task;
-EXPORT_PER_CPU_SYMBOL(current_task);
-
 /*
  * Return saved PC of a blocked thread.
  */
@@ -137,7 +135,7 @@ void __show_regs(struct pt_regs *regs, int all)
                ss = regs->ss & 0xffff;
                gs = get_user_gs(regs);
        } else {
-               sp = (unsigned long) (&regs->sp);
+               sp = kernel_stack_pointer(regs);
                savesegment(ss, ss);
                savesegment(gs, gs);
        }
@@ -262,7 +260,12 @@ int copy_thread(unsigned long clone_flags, unsigned long sp,
 
        task_user_gs(p) = get_user_gs(regs);
 
+       p->thread.io_bitmap_ptr = NULL;
        tsk = current;
+       err = -ENOMEM;
+
+       memset(p->thread.ptrace_bps, 0, sizeof(p->thread.ptrace_bps));
+
        if (unlikely(test_tsk_thread_flag(tsk, TIF_IO_BITMAP))) {
                p->thread.io_bitmap_ptr = kmemdup(tsk->thread.io_bitmap_ptr,
                                                IO_BITMAP_BYTES, GFP_KERNEL);
@@ -350,14 +353,21 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
                                 *next = &next_p->thread;
        int cpu = smp_processor_id();
        struct tss_struct *tss = &per_cpu(init_tss, cpu);
+       bool preload_fpu;
 
        /* never put a printk in __switch_to... printk() calls wake_up*() indirectly */
 
-       __unlazy_fpu(prev_p);
+       /*
+        * 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;
 
+       __unlazy_fpu(prev_p);
 
        /* we're going to use this soon, after a few expensive things */
-       if (next_p->fpu_counter > 5)
+       if (preload_fpu)
                prefetch(next->xstate);
 
        /*
@@ -398,6 +408,11 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
                     task_thread_info(next_p)->flags & _TIF_WORK_CTXSW_NEXT))
                __switch_to_xtra(prev_p, next_p, tss);
 
+       /* If we're going to preload the fpu context, make sure clts
+          is run while we're batching the cpu state updates. */
+       if (preload_fpu)
+               clts();
+
        /*
         * Leave lazy mode, flushing any hypercalls made here.
         * This must be done before restoring TLS segments so
@@ -407,15 +422,8 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
         */
        arch_end_context_switch(next_p);
 
-       /* 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
-        *
-        * tsk_used_math() checks prevent calling math_state_restore(),
-        * which can sleep in the case of !tsk_used_math()
-        */
-       if (tsk_used_math(next_p) && next_p->fpu_counter > 5)
-               math_state_restore();
+       if (preload_fpu)
+               __math_state_restore();
 
        /*
         * Restore %gs if needed (which is common)