Xen devel - Dec 2008 - Writing C program on Stubdom

Hi, list!

          Currently I am trying to write C programs on Stubdom. In my
understanding, the c-stubdom is trying to show us that we can just write
standard C programs,  linking it to mini-os,(with the APP_OBJS points to the
appropriate obj files), then we can run the program as a separate Xen
Domain, am I right?

          I successfully compiled the c-stubdom ( by "make c-stubdom"
in
XEN_ROOT/stubdom ), and i got the mini-os.gz. Does it mean that i can use it
as a kernel to create a new domain, and what it would do is simply out put
"hello wolrd" then hangs up? But i get the VMWare crash when i tried
to do
this. ( Yes, i deployed XEN 3.3 in VMware).

         On the other hand, to find out how stubdom links applications (such
ioemu, grub) with MiniOS, I examined the Makefile in XEN_ROOT/stubdom, I
noticed that it is achieved by passing "APP_OBJ= target objects" to
the make
command of miniOS. In the Makefile of MiniOS, I found the following scripts:

$(OBJ_DIR)/$(TARGET)_app.o: $(APP_OBJS) app.lds
    $(LD) -r -d $(LDFLAGS) -\( $^ -\) $(APP_LDLIBS) --undefined main -o $@

         Is the purpose of this scrpits to adjust the APP_OBJS according to
app.lds, so it can be linked to MiniOS?

then:

$(OBJ_DIR)/$(TARGET): links $(OBJS) $(OBJ_DIR)/$(TARGET)_app.o arch_lib
    $(LD) -r $(LDFLAGS) $(HEAD_OBJ) $(OBJ_DIR)/$(TARGET)_app.o $(OBJS)
$(LDARCHLIB) $(LDLIBS) -o $@.o
    $(OBJCOPY) -w -G $(GLOBAL_PREFIX)* -G _start $@.o $@.o

         Above scripts replaces the "__attribute__((weak)) int
app_main(start_info_t *si)" within XEN_ROOT/Extra/Mini-os/Kernel.c with the
adjusted APP_OBJS?

         Thanks!

-- 
Regards!
Ryan


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Hello,

阮安邦, le Fri 12 Dec 2008 17:01:06 +0800, a écrit :
> In my understanding, the c-stubdom is trying to show us that we can
> just write standard C programs, linking it to mini-os,(with the
> APP_OBJS points to the appropriate obj files), then we can run the
> program as a separate Xen Domain, am I right?
Yes.
> Does it mean that i can use it as a kernel to create a new domain, and
> what it would do is simply out put "hello wolrd" then hangs up?
Yes.
> But i get the VMWare crash when i tried to do this. (
> Yes, i deployed XEN 3.3 in VMware).
You mean _VMWare_ crashes?  Well that''s our fault then :)
> $(OBJ_DIR)/$(TARGET)_app.o: $(APP_OBJS) app.lds
>     $(LD) -r -d $(LDFLAGS) -\( $^ -\) $(APP_LDLIBS) --undefined main -o $@
>          
>          Is the purpose of this scrpits to adjust the APP_OBJS according to
> app.lds, so it can be linked to MiniOS?
Yes.
> $(OBJ_DIR)/$(TARGET): links $(OBJS) $(OBJ_DIR)/$(TARGET)_app.o arch_lib
>     $(LD) -r $(LDFLAGS) $(HEAD_OBJ) $(OBJ_DIR)/$(TARGET)_app.o $(OBJS) $
> (LDARCHLIB) $(LDLIBS) -o $@.o
>     $(OBJCOPY) -w -G $(GLOBAL_PREFIX)* -G _start $@.o $@.o
> 
>          Above scripts replaces the "__attribute__((weak)) int
app_main
> (start_info_t *si)" within XEN_ROOT/Extra/Mini-os/Kernel.c with the
adjusted
> APP_OBJS?
Yes, in order to replace the default "test" app_main of mini-os.

Samuel

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