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-rw-r--r--arch/x86/kernel/fpu/core.c18
1 files changed, 18 insertions, 0 deletions
diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c
index 1015af1ae562..375852cf8fac 100644
--- a/arch/x86/kernel/fpu/core.c
+++ b/arch/x86/kernel/fpu/core.c
@@ -753,6 +753,24 @@ void switch_fpu_return(void)
}
EXPORT_SYMBOL_GPL(switch_fpu_return);
+void fpregs_lock_and_load(void)
+{
+ /*
+ * fpregs_lock() only disables preemption (mostly). So modifying state
+ * in an interrupt could screw up some in progress fpregs operation.
+ * Warn about it.
+ */
+ WARN_ON_ONCE(!irq_fpu_usable());
+ WARN_ON_ONCE(current->flags & PF_KTHREAD);
+
+ fpregs_lock();
+
+ fpregs_assert_state_consistent();
+
+ if (test_thread_flag(TIF_NEED_FPU_LOAD))
+ fpregs_restore_userregs();
+}
+
#ifdef CONFIG_X86_DEBUG_FPU
/*
* If current FPU state according to its tracking (loaded FPU context on this