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

Pull x86 fpu changes from Ingo Molnar:
 "Various x86 FPU handling cleanups, refactorings and fixes (Borislav
  Petkov, Oleg Nesterov, Rik van Riel)"

* 'x86-fpu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (21 commits)
  x86/fpu: Kill eager_fpu_init_bp()
  x86/fpu: Don't allocate fpu->state for swapper/0
  x86/fpu: Rename drop_init_fpu() to fpu_reset_state()
  x86/fpu: Fold __drop_fpu() into its sole user
  x86/fpu: Don't abuse drop_init_fpu() in flush_thread()
  x86/fpu: Use restore_init_xstate() instead of math_state_restore() on kthread exec
  x86/fpu: Introduce restore_init_xstate()
  x86/fpu: Document user_fpu_begin()
  x86/fpu: Factor out memset(xstate, 0) in fpu_finit() paths
  x86/fpu: Change xstateregs_get()/set() to use ->xsave.i387 rather than ->fxsave
  x86/fpu: Don't abuse FPU in kernel threads if use_eager_fpu()
  x86/fpu: Always allow FPU in interrupt if use_eager_fpu()
  x86/fpu: __kernel_fpu_begin() should clear fpu_owner_task even if use_eager_fpu()
  x86/fpu: Also check fpu_lazy_restore() when use_eager_fpu()
  x86/fpu: Use task_disable_lazy_fpu_restore() helper
  x86/fpu: Use an explicit if/else in switch_fpu_prepare()
  x86/fpu: Introduce task_disable_lazy_fpu_restore() helper
  x86/fpu: Move lazy restore functions up a few lines
  x86/fpu: Change math_error() to use unlazy_fpu(), kill (now) unused save_init_fpu()
  x86/fpu: Don't do __thread_fpu_end() if use_eager_fpu()
  ...

1 files changed, 10 insertions, 29 deletions

diff --git a/arch/x86/kernel/xsave.c b/arch/x86/kernel/xsave.c
index cdc6cf903078..87a815b85f3e 100644
--- a/arch/x86/kernel/xsave.c
+++ b/arch/x86/kernel/xsave.c
@@ -342,7 +342,7 @@ int __restore_xstate_sig(void __user *buf, void __user *buf_fx, int size)
 			 config_enabled(CONFIG_IA32_EMULATION));
 
 	if (!buf) {
-		drop_init_fpu(tsk);
+		fpu_reset_state(tsk);
 		return 0;
 	}
 
@@ -416,7 +416,7 @@ int __restore_xstate_sig(void __user *buf, void __user *buf_fx, int size)
 		 */
 		user_fpu_begin();
 		if (restore_user_xstate(buf_fx, xstate_bv, fx_only)) {
-			drop_init_fpu(tsk);
+			fpu_reset_state(tsk);
 			return -1;
 		}
 	}
@@ -678,19 +678,13 @@ void xsave_init(void)
 	this_func();
 }
 
-static inline void __init eager_fpu_init_bp(void)
-{
-	current->thread.fpu.state =
-	    alloc_bootmem_align(xstate_size, __alignof__(struct xsave_struct));
-	if (!init_xstate_buf)
-		setup_init_fpu_buf();
-}
-
-void eager_fpu_init(void)
+/*
+ * setup_init_fpu_buf() is __init and it is OK to call it here because
+ * init_xstate_buf will be unset only once during boot.
+ */
+void __init_refok eager_fpu_init(void)
 {
-	static __refdata void (*boot_func)(void) = eager_fpu_init_bp;
-
-	clear_used_math();
+	WARN_ON(used_math());
 	current_thread_info()->status = 0;
 
 	if (eagerfpu == ENABLE)
@@ -701,21 +695,8 @@ void eager_fpu_init(void)
 		return;
 	}
 
-	if (boot_func) {
-		boot_func();
-		boot_func = NULL;
-	}
-
-	/*
-	 * This is same as math_state_restore(). But use_xsave() is
-	 * not yet patched to use math_state_restore().
-	 */
-	init_fpu(current);
-	__thread_fpu_begin(current);
-	if (cpu_has_xsave)
-		xrstor_state(init_xstate_buf, -1);
-	else
-		fxrstor_checking(&init_xstate_buf->i387);
+	if (!init_xstate_buf)
+		setup_init_fpu_buf();
 }
 
 /*