On Mon, Aug 31, 2015 at 2:28 AM, Gernot Heiser <[email protected]> wrote:
> On 31 Aug 2015, at 18:57 , Raymond Jennings <[email protected]> wrote: > > > Is there an easy way for one task to share address space with another task > directly or does it have to go through the kernel/os and be emulated? > > > there’s nothing stopping you mapping the same frame into two different > address spaces (provided you have the rights to do so). > > I noticed that support for mapping memory is mostly low level assignment > of physical frames to virtual frames via page tables, unlike Mach which > uses memory objects. > > IPC using shared memory policy needs to be considered and established. Shared read-write both processes need to have the (exact?) same levels. Shared rw --> ro is one way and the sender needs to be trusted to do the correct things with data it has access to. There is more to be considered... in a machine eyes-only needs a policy where a decision can be made but no other output is permitted policy. Without a policy and strategy things get unsecured in a hurry. One might simply use files and allow page cache to accelerate communication. Device drivers... ? -- T o m M i t c h e l l
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