Index: sys/stand/efiboot/exec.c
===================================================================
RCS file: /cvsroot/src/sys/stand/efiboot/exec.c,v
retrieving revision 1.19
diff -u -p -r1.19 exec.c
--- sys/stand/efiboot/exec.c	10 Oct 2020 19:17:39 -0000	1.19
+++ sys/stand/efiboot/exec.c	12 Dec 2020 09:36:10 -0000
@@ -41,8 +41,17 @@ extern char twiddle_toggle;
 
 u_long load_offset = 0;
 
+#ifndef PAGE_SIZE
+#define PAGE_SIZE	(4 * 1024)
+#endif
 #define	FDT_SPACE	(4 * 1024 * 1024)
-#define	FDT_ALIGN	((2 * 1024 * 1024) - 1)
+#define	FDT_ALIGN	(2 * 1024 * 1024)
+
+/*
+ * Wild guess at how big kernend_extra might get, or how much memory
+ * valloc_pages will use.
+ */
+#define KERNEL_EARLYALLOCATIONS	(32 * 4 * 1024)
 
 static EFI_PHYSICAL_ADDRESS initrd_addr, dtb_addr, rndseed_addr, efirng_addr;
 static u_long initrd_size = 0, dtb_size = 0, rndseed_size = 0, efirng_size = 0;
@@ -242,7 +251,7 @@ int
 exec_netbsd(const char *fname, const char *args)
 {
 	EFI_PHYSICAL_ADDRESS addr;
-	u_long marks[MARK_MAX], alloc_size;
+	u_long marks[MARK_MAX], alloc_size, fdt_offset;
 	EFI_STATUS status;
 	int fd, ohowto;
 
@@ -260,8 +269,17 @@ exec_netbsd(const char *fname, const cha
 		return EIO;
 	}
 	close(fd);
+
 	marks[MARK_END] = (((u_long) marks[MARK_END] + sizeof(int) - 1)) & (-sizeof(int));
-	alloc_size = marks[MARK_END] - marks[MARK_START] + FDT_SPACE + EFIBOOT_ALIGN;
+
+	alloc_size = marks[MARK_END] - marks[MARK_START];	// kernel size
+	alloc_size = (alloc_size + PAGE_SIZE - 1) & -PAGE_SIZE;
+	alloc_size += KERNEL_EARLYALLOCATIONS;
+	alloc_size = (alloc_size + FDT_ALIGN - 1) & ~(FDT_ALIGN - 1);
+
+	fdt_offset = alloc_size;
+	alloc_size += FDT_SPACE;				// fdt max space
+	alloc_size = (alloc_size + EFIBOOT_ALIGN - 1) & ~(EFIBOOT_ALIGN - 1);
 
 #ifdef EFIBOOT_ALLOCATE_MAX_ADDRESS
 	addr = EFIBOOT_ALLOCATE_MAX_ADDRESS;
@@ -279,7 +297,7 @@ exec_netbsd(const char *fname, const cha
 	}
 
 	memset(marks, 0, sizeof(marks));
-	load_offset = (addr + EFIBOOT_ALIGN) & ~(EFIBOOT_ALIGN - 1);
+	load_offset = (addr + EFIBOOT_ALIGN - 1) & ~(EFIBOOT_ALIGN - 1);
 	fd = loadfile(fname, marks, LOAD_KERNEL);
 	if (fd < 0) {
 		printf("boot: %s: %s\n", fname, strerror(errno));
@@ -308,7 +326,7 @@ exec_netbsd(const char *fname, const cha
 		load_file(get_rndseed_path(), 0, false,
 		    &rndseed_addr, &rndseed_size);
 
-		efi_fdt_init((marks[MARK_END] + FDT_ALIGN) & ~FDT_ALIGN, FDT_ALIGN + 1);
+		efi_fdt_init(marks[MARK_START] + fdt_offset, FDT_SPACE);
 		load_modules(fname);
 		load_fdt_overlays();
 		efi_fdt_initrd(initrd_addr, initrd_size);