Messages in this thread |  | | | Date | Wed, 15 Jul 2009 18:24:46 +0900 | | From | Paul Mundt <> | | Subject | Re: [PATCH v2] NOMMU: add support for Memory Protection Units (MPU) |
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On Tue, Jul 14, 2009 at 06:22:06PM +0100, David Howells wrote: > Mike Frysinger <vapier@gentoo.org> wrote: > > > Some architectures (like the Blackfin arch) implement some of the > > "simpler" features that one would expect out of a MMU such as memory > > protection. In our case, we actually get read/write/exec protection > > down to the page boundary so processes can't stomp on each other let > > alone the kernel. There is a performance decrease (which depends greatly > > on the workload) however as the hardware/software interaction was not > > optimized at design time. > > It occurs to me that I could probably test this on FRV by using the MMU in a > limited way. How do you actually keep track of the protections applied? Do > you have a single global page table that is managed by the mmap code on a > per-VMA basis? > SH can do this as well for the single-address-space mode in the MMU, but in that case I would still use a global page table.
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