diff --git a/Documentation/x86_64/boot-options.txt b/Documentation/x86_64/boot-options.txt
index e97a4c8fe6ead5ff4220c7e9f7972d833a852581..74b77f9e91bc5cc5692eee19fc0b4b6be3a49302 100644
--- a/Documentation/x86_64/boot-options.txt
+++ b/Documentation/x86_64/boot-options.txt
@@ -203,6 +203,7 @@ IOMMU
 	    When off all DMA over >4GB is forced through an IOMMU or bounce
 	    buffering.
    nodac    Forbid DMA >4GB
+   panic    Always panic when IOMMU overflows
 
   swiotlb=pages[,force]
 
diff --git a/arch/x86_64/kernel/pci-dma.c b/arch/x86_64/kernel/pci-dma.c
index 58be7929b4e2d8b65cde7f1ca620b1b64acdd870..f8d857453f8afaf5fc839060cf1ad07dc69d13dc 100644
--- a/arch/x86_64/kernel/pci-dma.c
+++ b/arch/x86_64/kernel/pci-dma.c
@@ -245,6 +245,7 @@ EXPORT_SYMBOL(dma_set_mask);
    noaperture Don't touch the aperture for AGP.
    allowdac Allow DMA >4GB
    nodac    Forbid DMA >4GB
+   panic    Force panic when IOMMU overflows
 */
 __init int iommu_setup(char *p)
 {