On Fri, 12 Apr 2024 14:50:46 GMT, Vladimir Kempik <vkem...@openjdk.org> wrote:
> Hello Sergey. W^X mode was initially forced by Apple to prevent writing to > executable memory, as a security feature. This change just eliminates this > security feature at all, doesn't it ? Basically: "want to write to Executable > memory ? ok, here you go" Yes @VladimirKempik, you are right. No, we should not do this. Instead, when we enter the VM we could track the current state of W^X and whenever we enter a block that needs to write into code space we would set W if needed. When we leave the VM or when we call back into Java we would set X, if needed. The cost of doing this would be small, but we'd have to find all the blocks that need to write into code space. This might be more effort than we want to make, though. So where would be need to make the transitions to W? At a guess, whenever we start assembling something, and in all of the methods in nativeInst_aarch64.?pp, and in class Patcher. And to X, in the call stub and a few other places. That would minimize the transitions exactly to the set of places we actually need. ------------- PR Comment: https://git.openjdk.org/jdk/pull/18762#issuecomment-2051977752
