X-Git-Url: https://gitweb.dragonflybsd.org/dragonfly.git/blobdiff_plain/5c26bcd6e16a9635d747a67bbcec500e43b8e91f..cc9b6223b2987bd6f07ca869665f420285917156:/sys/platform/pc64/x86_64/exception.S

diff --git a/sys/platform/pc64/x86_64/exception.S b/sys/platform/pc64/x86_64/exception.S
index 55343042d2..8377d21325 100644
--- a/sys/platform/pc64/x86_64/exception.S
+++ b/sys/platform/pc64/x86_64/exception.S
@@ -48,6 +48,8 @@
 
 	.text
 
+	.globl	lwkt_switch_return
+
 /*****************************************************************************/
 /* Trap handling                                                             */
 /*****************************************************************************/
@@ -418,8 +420,17 @@ nmi_restoreregs:
  *
  * The MP lock is not held at any point but the critcount is bumped
  * on entry to prevent interruption of the trampoline at a bad point.
+ *
+ * This is effectively what td->td_switch() returns to.  It 'returns' the
+ * old thread in %rax and since this is not returning to a td->td_switch()
+ * call from lwkt_switch() we must handle the cleanup for the old thread
+ * by calling lwkt_switch_return().
+ *
+ * fork_trampoline(%rax:otd, %rbx:func, %r12:arg)
  */
 ENTRY(fork_trampoline)
+	movq	%rax,%rdi
+	call	lwkt_switch_return
 	movq	PCPU(curthread),%rax
 	decl	TD_CRITCOUNT(%rax)