Index: head/sys/amd64/include/vmparam.h
===================================================================
--- head/sys/amd64/include/vmparam.h
+++ head/sys/amd64/include/vmparam.h
@@ -254,6 +254,11 @@
 #define	VM_BATCHQUEUE_SIZE	31
 
 /*
+ * The pmap can create non-transparent large page mappings.
+ */
+#define	PMAP_HAS_LARGEPAGES	1
+
+/*
  * Need a page dump array for minidump.
  */
 #define MINIDUMP_PAGE_TRACKING	1
Index: head/sys/arm/include/vmparam.h
===================================================================
--- head/sys/arm/include/vmparam.h
+++ head/sys/arm/include/vmparam.h
@@ -194,6 +194,11 @@
 #define	DEVMAP_MAX_VADDR	ARM_VECTORS_HIGH
 
 /*
+ * No non-transparent large page support in the pmap.
+ */
+#define	PMAP_HAS_LARGEPAGES	0
+
+/*
  * Need a page dump array for minidump.
  */
 #define MINIDUMP_PAGE_TRACKING	1
Index: head/sys/arm64/include/vmparam.h
===================================================================
--- head/sys/arm64/include/vmparam.h
+++ head/sys/arm64/include/vmparam.h
@@ -244,6 +244,11 @@
 #define	DEVMAP_MAX_VADDR	VM_MAX_KERNEL_ADDRESS
 
 /*
+ * The pmap can create non-transparent large page mappings.
+ */
+#define	PMAP_HAS_LARGEPAGES	1
+
+/*
  * Need a page dump array for minidump.
  */
 #define MINIDUMP_PAGE_TRACKING	1
Index: head/sys/i386/include/vmparam.h
===================================================================
--- head/sys/i386/include/vmparam.h
+++ head/sys/i386/include/vmparam.h
@@ -241,6 +241,11 @@
 #define	DMAP_TO_PHYS(x)	({ panic("No direct map exists"); 0; })
 
 /*
+ * No non-transparent large page support in the pmap.
+ */
+#define	PMAP_HAS_LARGEPAGES	0
+
+/*
  * Need a page dump array for minidump.
  */
 #define MINIDUMP_PAGE_TRACKING	1
Index: head/sys/kern/uipc_shm.c
===================================================================
--- head/sys/kern/uipc_shm.c
+++ head/sys/kern/uipc_shm.c
@@ -1067,10 +1067,8 @@
 		return (EINVAL);
 
 	largepage = (shmflags & SHM_LARGEPAGE) != 0;
-#if !defined(__amd64__)
-	if (largepage)
+	if (largepage && !PMAP_HAS_LARGEPAGES)
 		return (ENOTTY);
-#endif
 
 	/*
 	 * Currently only F_SEAL_SEAL may be set when creating or opening shmfd.
Index: head/sys/mips/include/vmparam.h
===================================================================
--- head/sys/mips/include/vmparam.h
+++ head/sys/mips/include/vmparam.h
@@ -198,6 +198,11 @@
 #define	DMAP_TO_PHYS(x)	MIPS_DIRECT_TO_PHYS(x)
 
 /*
+ * No non-transparent large page support in the pmap.
+ */
+#define	PMAP_HAS_LARGEPAGES	0
+
+/*
  * Need a page dump array for minidump.
  */
 #define MINIDUMP_PAGE_TRACKING	1
Index: head/sys/powerpc/include/vmparam.h
===================================================================
--- head/sys/powerpc/include/vmparam.h
+++ head/sys/powerpc/include/vmparam.h
@@ -327,4 +327,9 @@
 	KASSERT(hw_direct_map, ("Direct map not provided by PMAP"));	\
 	(x) &~ DMAP_BASE_ADDRESS; })
 
+/*
+ * No non-transparent large page support in the pmap.
+ */
+#define	PMAP_HAS_LARGEPAGES	0
+
 #endif /* _MACHINE_VMPARAM_H_ */
Index: head/sys/riscv/include/vmparam.h
===================================================================
--- head/sys/riscv/include/vmparam.h
+++ head/sys/riscv/include/vmparam.h
@@ -237,6 +237,11 @@
 #define	DEVMAP_MAX_VADDR	VM_MAX_KERNEL_ADDRESS
 
 /*
+ * No non-transparent large page support in the pmap.
+ */
+#define	PMAP_HAS_LARGEPAGES	0
+
+/*
  * Need a page dump array for minidump.
  */
 #define MINIDUMP_PAGE_TRACKING	1
Index: head/sys/vm/vm_fault.c
===================================================================
--- head/sys/vm/vm_fault.c
+++ head/sys/vm/vm_fault.c
@@ -487,6 +487,8 @@
 	 * populate only busies the first page in superpage run.
 	 */
 	if (bdry_idx != 0) {
+		KASSERT(PMAP_HAS_LARGEPAGES,
+		    ("missing pmap support for large pages"));
 		m = vm_page_lookup(fs->first_object, pager_first);
 		vm_fault_populate_check_page(m);
 		VM_OBJECT_WUNLOCK(fs->first_object);