diff --git a/arch/arm/setup.c b/arch/arm/setup.c
index 05b405b..b65023c 100644
--- a/arch/arm/setup.c
+++ b/arch/arm/setup.c
@@ -9,13 +9,6 @@
 #include <libfdt.h>
 
 /*
- * This structure contains start-of-day info, such as pagetable base pointer,
- * address of the shared_info structure, and things like that.
- * On x86, the hypervisor passes it to us. On ARM, we fill it in ourselves.
- */
-union start_info_union start_info_union;
-
-/*
  * Shared page for communicating with the hypervisor.
  * Events flags go here, for example.
  */
@@ -47,7 +40,6 @@ void arch_init(void *dtb_pointer, uint32_t physical_offset)
     /* Map shared_info page */
     HYPERVISOR_shared_info = map_shared_info(NULL);
 
-    /* Fill in start_info */
     get_console(NULL);
     get_xenbus(NULL);
 
diff --git a/arch/x86/setup.c b/arch/x86/setup.c
index 278e88f..50aa504 100644
--- a/arch/x86/setup.c
+++ b/arch/x86/setup.c
@@ -40,12 +40,6 @@
 shared_info_t *HYPERVISOR_shared_info;
 
 /*
- * This structure contains start-of-day info, such as pagetable base pointer,
- * address of the shared_info structure, and things like that.
- */
-union start_info_union start_info_union;
-
-/*
  * Just allocate the kernel stack here. SS:ESP is set up to point here
  * in head.S.
  */
@@ -151,7 +145,6 @@ arch_init(void *par)
 	/* Setup memory management info from start_info. */
 	arch_mm_preinit(par);
 
-	/* Copy the start_info struct to a globally-accessible area. */
 	/* WARN: don't do printk before here, it uses information from
 	   shared_info. Use xprintk instead. */
 	get_console(par);
@@ -162,7 +155,6 @@ arch_init(void *par)
 	HYPERVISOR_shared_info = map_shared_info(par);
 
 	si = par;
-	memcpy(&start_info, si, sizeof(*si));
 
 	/* print out some useful information  */
 	printk("Xen Minimal OS!\n");
diff --git a/daytime.c b/daytime.c
index 7dc0de0..6049e78 100644
--- a/daytime.c
+++ b/daytime.c
@@ -60,7 +60,7 @@ void run_server(void *p)
 }
 
 
-int app_main(start_info_t *si)
+int app_main(void *p)
 {
     create_thread("server", run_server, NULL);
     return 0;
diff --git a/include/hypervisor.h b/include/hypervisor.h
index 7c44702..3073a8a 100644
--- a/include/hypervisor.h
+++ b/include/hypervisor.h
@@ -26,17 +26,6 @@
 #include <xen/hvm/hvm_op.h>
 #include <mini-os/traps.h>
 
-/*
- * a placeholder for the start of day information passed up from the hypervisor
- */
-union start_info_union
-{
-    start_info_t start_info;
-    char padding[512];
-};
-extern union start_info_union start_info_union;
-#define start_info (start_info_union.start_info)
-
 /* hypervisor.c */
 #ifndef CONFIG_PARAVIRT
 int hvm_get_parameter(int idx, uint64_t *value);
diff --git a/kernel.c b/kernel.c
index f22997e..0d84a9b 100644
--- a/kernel.c
+++ b/kernel.c
@@ -110,9 +110,9 @@ static void shutdown_thread(void *p)
 
 
 /* This should be overridden by the application we are linked against. */
-__attribute__((weak)) int app_main(start_info_t *si)
+__attribute__((weak)) int app_main(void *p)
 {
-    printk("kernel.c: dummy main: start_info=%p\n", si);
+    printk("kernel.c: dummy main: par=%p\n", p);
     return 0;
 }
 
@@ -149,7 +149,7 @@ void start_kernel(void)
 #endif
 
     /* Call (possibly overridden) app_main() */
-    app_main(&start_info);
+    app_main(NULL);
 
     /* Everything initialised, start idle thread */
     run_idle_thread();
diff --git a/main.c b/main.c
index 71e3be3..263364c 100644
--- a/main.c
+++ b/main.c
@@ -185,10 +185,10 @@ void _exit(int ret)
     do_exit();
 }
 
-int app_main(start_info_t *si)
+int app_main(void *p)
 {
-    printk("main.c: dummy main: start_info=%p\n", si);
-    main_thread = create_thread("main", call_main, si);
+    printk("main.c: dummy main: par=%p\n", p);
+    main_thread = create_thread("main", call_main, p);
     return 0;
 }
 #endif
diff --git a/test.c b/test.c
index 154af49..42a2666 100644
--- a/test.c
+++ b/test.c
@@ -552,28 +552,28 @@ static void shutdown_thread(void *p)
 }
 #endif
 
-int app_main(start_info_t *si)
+int app_main(void *p)
 {
-    printk("Test main: start_info=%p\n", si);
+    printk("Test main: par=%p\n", p);
 #ifdef CONFIG_XENBUS
-    create_thread("xenbus_tester", xenbus_tester, si);
+    create_thread("xenbus_tester", xenbus_tester, p);
 #endif
-    create_thread("periodic_thread", periodic_thread, si);
+    create_thread("periodic_thread", periodic_thread, p);
 #ifdef CONFIG_NETFRONT
-    create_thread("netfront", netfront_thread, si);
+    create_thread("netfront", netfront_thread, p);
 #endif
 #ifdef CONFIG_BLKFRONT
-    create_thread("blkfront", blkfront_thread, si);
+    create_thread("blkfront", blkfront_thread, p);
 #endif
 #if defined(CONFIG_FBFRONT) && defined(CONFIG_KBDFRONT)
-    create_thread("fbfront", fbfront_thread, si);
-    create_thread("kbdfront", kbdfront_thread, si);
+    create_thread("fbfront", fbfront_thread, p);
+    create_thread("kbdfront", kbdfront_thread, p);
 #endif
 #ifdef CONFIG_PCIFRONT
-    create_thread("pcifront", pcifront_thread, si);
+    create_thread("pcifront", pcifront_thread, p);
 #endif
 #ifdef CONFIG_XENBUS
-    create_thread("shutdown", shutdown_thread, si);
+    create_thread("shutdown", shutdown_thread, p);
 #endif
     return 0;
 }
