# HG changeset patch
# User Taylor R Campbell <riastradh@NetBSD.org>
# Date 1593986494 0
#      Sun Jul 05 22:01:34 2020 +0000
# Branch trunk
# Node ID e3ed1cb517acd719687149cf86009853595595c5
# Parent  ccf3ee876dd2fa7edc8531fa6e52bbc168efa9ca
WIP: fpu_save_lwp: try to avoid stts/MDL_FPU_IN_CPU race

diff -r ccf3ee876dd2 -r e3ed1cb517ac sys/arch/x86/x86/fpu.c
--- a/sys/arch/x86/x86/fpu.c	Sun Jul 05 14:24:05 2020 +0000
+++ b/sys/arch/x86/x86/fpu.c	Sun Jul 05 22:01:34 2020 +0000
@@ -155,8 +155,28 @@ fpu_save_lwp(struct lwp *l)
 	kpreempt_disable();
 	if (l->l_md.md_flags & MDL_FPU_IN_CPU) {
 		KASSERT((l->l_flag & LW_SYSTEM) == 0);
+#if 1
+		/* XXX inline fpu_area_save */
+		switch (x86_fpu_save) {
+		case FPU_SAVE_FSAVE:
+			fnsave(area);
+			break;
+		case FPU_SAVE_FXSAVE:
+			fxsave(area);
+			break;
+		case FPU_SAVE_XSAVE:
+			xsave(area, x86_xsave_features);
+			break;
+		case FPU_SAVE_XSAVEOPT:
+			xsaveopt(area, x86_xsave_features);
+			break;
+		}
+		l->l_md.md_flags &= ~MDL_FPU_IN_CPU;
+		stts();
+#else
 		fpu_area_save(area, x86_xsave_features);
 		l->l_md.md_flags &= ~MDL_FPU_IN_CPU;
+#endif
 	}
 	kpreempt_enable();
 }