Commit 15a7d5ee authored by Committed by ROOLBrowse files
Add Service_PagesUnsafe64 & PagesSafe64
These use a page block with a 64bit address fields (matching OS_Memory 64). The page list(s) contain the full list of pages involved in the operation, unlike the 32bit PagesUnsafe / PagesSafe calls, which only list pages which have 32bit addresses. The kernel issues the service calls in the following order: 1. Service_PagesUnsafe64 2. Service_PagesUnsafe 3. Service_PagesSafe 4. Service_PagesSafe64 Since only one PagesUnsafe operation can occur at a time, a program which supports both service calls can safely ignore the PagesUnsafe / PagesSafe calls if a PagesUnsafe64 operation is in progress (the PagesUnsafe call will only list a subset of the pages from the PagesUnsafe64 call). The 32bit PagesUnsafe / PagesSafe calls will be skipped if no 32bit pages are being replaced. The addition of these calls means that NeedsSpecificPages DAs (and PMPs) can now request pages which have large physical addresses. Note that the page replacement logic now has the restriction that pages which have 32bit physical addresses can only be replaced by other pages which have 32bit physical addresses. This is necessary to ensure that users of the old 32bit APIs see the page replacement take place. However it does mean that programs will be unable to claim pages of low RAM which are in use if there are not enough free low RAM pages in the free pool. A future optimisation would be to update the service calls so that they don't list required pages which are in the free pool; if all the required pages are in the free pool this would allow the service calls (and FIQ claiming) to be skipped completely.
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