Фото: Hannah Mckay / Reuters
What surprised me was that this entire walk is fully hardware-driven -- no microcode involvement at all. The state machine reads the page directory entry, reads the page table entry, checks permissions, and writes back the Accessed and Dirty bits, all autonomously. Since it's hardware-driven, it runs in parallel with the microcode and needs its own memory bus arbitration -- the paging unit must share the bus with both data accesses from the microcode and prefetch requests from the instruction queue.
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While we do recognize the importance of platform security and user safety, the Android platform already includes multiple security mechanisms that do not require central registration. Forcibly injecting an alien security model that runs counter to Android’s historic open nature threatens innovation, competition, privacy, and user freedom. We urge Google to withdraw this policy and work with the open-source and security communities on less restrictive alternatives.
The pieces of this medieval puzzle are starting to come together. But there are still some questions.