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I fully expect apples M1 chip to get a spectre type vulnerability at some point and then any improvements it had will disappear.
by thinkingemote 5y ago
I fully expect apples M1 chip to get a spectre type vulnerability at some point and then any improvements it had will disappear.
- mhh__ 5y agoM1 is vulnerable to Spectre (some variants at least) as far as I'm aware. Any speculation around memory accesses will yield this.
- zsmi 5y agoThat why the solution is to only allow speculation when it's "ok". M1 is believed to have a number of Spectre-esq security mechanisms built into it to determine just that. For example: https://patents.google.com/patent/US20200192673A1 https://patents.google.com/patent/US20200192673A1 Also, In dougallj's code [1] the zero of registers should be superfluous so it is assumed the function below is needed to make the experiments run stably by claiming ownership of the registers as part of a general anti-speculation security mechanism. static int add_prep(uint32_t *ibuf, int instr_type); The M1 explainer [2] has lot of interesting ideas like this contained inside it. [1] https://gist.github.com/dougallj/5bafb113492047c865c0c8cfbc930155 https://gist.github.com/dougallj/5bafb113492047c865c0c8cfbc9... [2] https://news.ycombinator.com/item?id=28549954 https://news.ycombinator.com/item?id=28549954