rom service in user space / how to add Rom_module - users

3 Sep 2009


      Hi,
I've implemented my own rom service based on Genode::Rom_root and
Genode::Rom_fs inside a server. Basically the service seems to work.
If I open a Rom_connection on a file that I've added to my Rom_fs
before, I get a valid Dataspace_capability.
By using a Genode::Dataspace_client, I can see that the size and the
base address of the Dataspace correspond to the values that I've passed
to the Rom_module I've inserted into my Rom_fs before.
The problem is, that the data inside the Dataspace is 0.
Here the code:
Dataspace_capability file_cap;
    Rom_connection rom(filename, unique_name);
    try {
        file_cap = rom.dataspace();
    } catch (Rom_file_missing) {
        printf("Error: Could not access file "%s" from ROM
service.\n", filename);
        return 0;
    }
if(!file_cap.valid())
        PWRN("file cap not valid!!");
    void* addr = env()->rm_session()->attach(file_cap);
    Genode::Dataspace_client dsc(file_cap);
    PDBG("rom module filename: %s", filename);
    PDBG("rom module base address: 0x%lx", dsc.phys_addr());
    PDBG("rom module size: 0x%zx", dsc.size());
    PDBG("some data: 0x%x", *(int*)addr);
.. and the corresponding output:
rom module filename: pci_drv
rom module base address: 0x3333000
rom module size: 0x26000
some data: 0x0
My understanding is, that the constructor of Rom_module
needs a physical base address.
How can I copy data to a memory location, that is still available in
another context?
I've tried out the following but this does not work:
// for now we copy data from core's to our local rom service
    Genode::Dataspace_capability file_cap;
    Rom_connection rom(filename);
    try {
        file_cap = rom.dataspace();
    } catch (Rom_file_missing) {
        printf("Error: Could not access file "%s" from ROM
service.\n", filename);
    }
void* addr = env()->rm_session()->attach(file_cap);
    Genode::Dataspace_client dsc_source(file_cap);
/* create new Rom_module */
    Genode::Ram_dataspace *ram_dsc = new (env()->heap())
Genode::Ram_dataspace(env()->ram_session(), dsc_source.size());
    Genode::Dataspace_client dsc(ram_dsc->cap());
Genode::memcpy(ram_dsc->local_addr<void>(), addr,
dsc_source.size());
Rom_module *r = new (&_sliced_heap) Rom_module(dsc.phys_addr(),
dsc_source.size(), filename);
    PDBG("rom module filename: %s", filename);
    PDBG("rom module base address: 0x%lx", dsc_source.phys_addr());
    PDBG("rom module size: 0x%zx", dsc_source.size());
    PDBG("dataspace base address: 0x%lx", dsc.phys_addr());
    PDBG("some data: 0x%x", *(int*)ram_dsc->local_addr<void>());
    _rom_fs.insert(r);
    _rom_fs.print_fs();
The output in this context is ok:
rom module filename: pci_drv
rom module base address: 0x3140000
rom module size: 0x26000
dataspace base address: 0x3333000
some data: 0x464c457f
Is there an Allocator that I can use?
Thx,
Oliver