Re: [PATCH v18 24/25] x86/cet/shstk: Add arch_prctl functions for shadow stack
From: Yu, Yu-cheng <hidden>
Date: 2021-01-29 19:59:55
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linux-arch, linux-doc, linux-mm, lkml
On 1/29/2021 11:15 AM, Dave Hansen wrote:
On 1/29/21 10:56 AM, Yu, Yu-cheng wrote:quoted
On 1/29/2021 9:07 AM, Dave Hansen wrote:quoted
On 1/27/21 1:25 PM, Yu-cheng Yu wrote:
[...]
quoted
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What's the point of doing copy_status_to_user() if the processor doesn't support CET? In other words, shouldn't this be below the CPU feature check?The thought was to tell the difference between the kernel itself does not support CET and the system does not have CET. And, if the kernel supports it, show CET status of the thread.Why would that matter to userspace? If they want to know if the processor has CET support there are existing ways to do it. I don't think this should be part of the ABI.
Ok, I will make it: if (!cpu_feature_enabled(X86_FEATURE_CET)) ...