Add stubdomain support. See stubdom/README for usage details.

- Move PAGE_SIZE and STACK_SIZE into __PAGE_SIZE and __STACK_SIZE in
  arch_limits.h so as to permit getting them from there without
  pulling all the internal Mini-OS defines.
- Setup a xen-elf cross-compilation environment in stubdom/cross-root
- Add a POSIX layer on top of Mini-OS by linking against the newlib C
  library and lwIP, and implementing the Unixish part in mini-os/lib/sys.c
- Cross-compile zlib and libpci too.
- Add an xs.h-compatible layer on top of Mini-OS' xenbus.
- Cross-compile libxc with an additional xc_minios.c and a few things
  disabled.
- Cross-compile ioemu with an additional block-vbd, but without sound,
  tpm and other details.  A few hacks are needed:
  - Align ide and scsi buffers at least on sector size to permit
  direct transmission to the block backend. While we are at it, just
  page-align it to possibly save a segment. Also, limit the scsi
  buffer size because of limitations of the block paravirtualization
  protocol.
  - Allocate big tables dynamically rather that letting them go to
  bss: when Mini-OS gets installed in memory, bss is not lazily
  allocated, and doing so during Mini-OS is unnecessarily trick while
  we can simply use malloc.
- Had to change the Mini-OS compilation somehow, so as to export
  Mini-OS compilation flags to the Makefiles of libxc and ioemu.

Signed-off-by: Samuel Thibault <samuel.thibault@eu.citrix.com>

1 files changed, 44 insertions, 0 deletions

diff --git a/extras/mini-os/sched.c b/extras/mini-os/sched.c
index 18b3f01538..19a102f056 100644
--- a/extras/mini-os/sched.c
+++ b/extras/mini-os/sched.c
@@ -56,6 +56,7 @@
 
 struct thread *idle_thread = NULL;
 LIST_HEAD(exited_threads);
+static int threads_started;
 
 void inline print_runqueue(void)
 {
@@ -172,6 +173,9 @@ struct thread* create_thread(char *name, void (*function)(void *), void *data)
     /* Not runable, not exited, not sleeping */
     thread->flags = 0;
     thread->wakeup_time = 0LL;
+#ifdef HAVE_LIBC
+    _REENT_INIT_PTR((&thread->reent))
+#endif
     set_runnable(thread);
     local_irq_save(flags);
     if(idle_thread != NULL) {
@@ -185,6 +189,42 @@ struct thread* create_thread(char *name, void (*function)(void *), void *data)
     return thread;
 }
 
+#ifdef HAVE_LIBC
+static struct _reent callback_reent;
+struct _reent *__getreent(void)
+{
+    struct _reent *_reent;
+
+    if (!threads_started)
+	_reent = _impure_ptr;
+    else if (in_callback)
+	_reent = &callback_reent;
+    else
+	_reent = &get_current()->reent;
+
+#ifndef NDEBUG
+#if defined(__x86_64__) || defined(__x86__)
+    {
+#ifdef __x86_64__
+	register unsigned long sp asm ("rsp");
+#else
+	register unsigned long sp asm ("esp");
+#endif
+	if ((sp & (STACK_SIZE-1)) < STACK_SIZE / 16) {
+	    static int overflowing;
+	    if (!overflowing) {
+		overflowing = 1;
+		printk("stack overflow\n");
+		BUG();
+	    }
+	}
+    }
+#endif
+#endif
+    return _reent;
+}
+#endif
+
 void exit_thread(void)
 {
     unsigned long flags;
@@ -228,6 +268,7 @@ void wake(struct thread *thread)
 void idle_thread_fn(void *unused)
 {
     s_time_t until;
+    threads_started = 1;
     unsigned long flags;
     struct list_head *iterator;
     struct thread *next, *thread;
@@ -297,6 +338,9 @@ void init_sched(void)
 {
     printk("Initialising scheduler\n");
 
+#ifdef HAVE_LIBC
+    _REENT_INIT_PTR((&callback_reent))
+#endif
     idle_thread = create_thread("Idle", idle_thread_fn, NULL);
     INIT_LIST_HEAD(&idle_thread->thread_list);
 }