ARM64 MMU fixes #72706
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ARM64 MMU fixes #72706
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Existing code confused table usage and table reference counts together. This obviously doesn't work. A table with one reference to it and one populated PTE is not the same as a table with 2 references to it and no PTe in use. So split the two concepts and adjust the code accordingly. A page needs to have its PTE usage count drop to zero before the last reference is released. When both counts are 0 then the page is free. Signed-off-by: Nicolas Pitre <npitre@baylibre.com>
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This code was never formally tested before... and without the preceding commit it obviously didn't work either. Signed-off-by: Nicolas Pitre <npitre@baylibre.com>
carlocaione
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May 22, 2024
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Looking at my own code I couldn't convince myself it was OK.
So I wrote a test and guess what? The code was broken... of course.
Here's the fix which required a slight rethinking of the page table
usage tracking. And more tests.