Morello copy_page cherry-pick#22
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heshamelmatary wants to merge 2 commits into
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Regular writes zero the capability tags in memory, which is exactly what we want in clear_page(), but in copy_page() we want to preserve the tags of the source page. We can achieve this by using capability loads/stores to copy both data and tags. Signed-off-by: Kevin Brodsky <kevin.brodsky@arm.com>
We have just done away with runtime detection for Morello in early initialisation paths. As a result, standard runtime detection based on the Morello CPU capability (ARM64_MORELLO) is now pointless (and misleading). Remove all uses of the ARM64_MORELLO capability. In assembly, this allows us to simplify quite a few paths. In C, the CPU capability is only used through the system_supports_morello() function. We preserve that function for convenience, making it rely purely on the CONFIG macro. Where it is used inside a code region that is already #ifdef'd on the macro, it becomes a no-op and we remove it. The Morello CPU feature itself is preserved, as well as runtime detection for it (based on the Morello and TTPBHA ID fields). This is not essential, but makes it easy to keep HWCAP2_MORELLO exposed to userspace, and reading the ID fields is marginally useful in case Morello hardware somehow did not set them to the right value. Signed-off-by: Kevin Brodsky <kevin.brodsky@arm.com>
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Can probably squash both commits of @kevin-brodsky-arm would prefer that. |
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