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This patch extends the RAM session interface with the ability to allocate DMA buffers. The client specifies the type of RAM dataspace to allocate via the new 'cached' argument of the 'Ram_session::alloc()' function. By default, 'cached' is true, which correponds to the common case and the original behavior. When setting 'cached' to 'false', core takes the precautions needed to register the memory as uncached in the page table of each process that has the dataspace attached. Currently, the support for allocating DMA buffers is implemented for Fiasco.OC only. On x86 platforms, it is generally not needed. But on platforms with more relaxed cache coherence (such as ARM), user-level device drivers should always use uncacheable memory for DMA transactions.
This is the example operating system based on the Genode OS framework: :_Init_: is the first real process in the system. The provided implementation uses a very simple XML parser to read its configuration files. :_Drivers_: The example OS has basic drivers for frame buffer, mouse and keyboard input, the PCI bus, the real-time clock, and system-specific timers. :_Server_: The only server in the example OS is Nitpicker, a minimal-complexity GUI server. :_Test_: are also part of the example OS. You may have a look at the fork bomb as a simple system stress test. :_Ldso_: is the dynamic linker used for loading executables that are linked against shared libraries. :_Lib_: contains libraries used by the components of the OS repository, in particular the device-driver kit, the alarm framework, and support for dynamic linking.