Context Switching Primitives for AArch64 #744
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…i-rs is fully merged
…uld be set in descriptors.
…alization to `memory`
…plemented the creation and filling of a new page table; Implemented the switch to the new page table
This reverts commit ff3944a.
36 tasks
…h64-context-switching
…h64-context-switching
kevinaboos
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Jan 3, 2023
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Looks good!
Linux only saves/restores x18 - x29 on aarch64, which apparently corresponds to the set of callee-saved registers. If you change your implementation to that, does everything still work correctly?
https://github.com/torvalds/linux/blob/69b41ac87e4a664de78a395ff97166f0b2943210/arch/arm64/kernel/entry.S#L820
… "first register" & rename fr/lr
Indeed, it still works correctly 👌 |
kevinaboos
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Jan 4, 2023
…h64-context-switching
Co-authored-by: Kevin Boos <[email protected]>
kevinaboos
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Jan 11, 2023
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* Currently this only saves callee-saved registers, which includes `x19` through `x30`, in which `x29` is the frame register and `x30` is the link register (holds the return address). * We designate `x28` as the register used to pass a new task's ID to its entry point. b88a23a
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This builds on #701.
This draft PR contains "regular" context switching primitives for aarch64:
context_switch_regularfunction (same signature as on x86_64):_prev_stack_pointer),_next_stack_pointer_value),create_stackis a utility function which allocates a 16-page long initial task stack; you have to give it a function pointer (such as the address oflanding_pad) which will be executed if you usecontext_switch_regularwith that new stack.landing_padis a "task" function which simply re-triggers a context switch to return to the original main task.These are used in
mainjust before infinite looping as a demonstration.