diff --git a/sys/powerpc/aim/trap_subr32.S b/sys/powerpc/aim/trap_subr32.S
index 7c154a8da38..80329cd0ff6 100644
--- a/sys/powerpc/aim/trap_subr32.S
+++ b/sys/powerpc/aim/trap_subr32.S
@@ -748,6 +748,8 @@ k_trap:
 /* Call C interrupt dispatcher: */
 trapagain:
 	addi	%r3,%r1,8
+	addi	%r4,%r1,-4		/* Clear any existing reservations */
+	stwcx.	%r3,0,%r4		
 	bl	CNAME(powerpc_interrupt)
 	.globl	CNAME(trapexit)		/* backtrace code sentinel */
 CNAME(trapexit):
diff --git a/sys/powerpc/aim/trap_subr64.S b/sys/powerpc/aim/trap_subr64.S
index 5d4148a55d8..66c543f4e2a 100644
--- a/sys/powerpc/aim/trap_subr64.S
+++ b/sys/powerpc/aim/trap_subr64.S
@@ -508,6 +508,8 @@ trapagain:
 	lis	%r3,tocbase@ha
 	ld	%r2,tocbase@l(%r3)
 	addi	%r3,%r1,48
+	addi	%r4,%r1,-8		/* Clear any existing reservations */
+	stdcx.	%r3,0,%r4		
 	bl	CNAME(powerpc_interrupt)
 	nop