Re: [PATCH v5 06/39] x86/fpu: Add helper for modifying xstate
From: "Edgecombe, Rick P" <rick.p.edgecombe@intel.com>
Date: 2023-02-01 17:32:48
Also in:
linux-arch, linux-doc, linux-mm, lkml
On Wed, 2023-02-01 at 12:01 +0100, Borislav Petkov wrote:
On Thu, Jan 19, 2023 at 01:22:44PM -0800, Rick Edgecombe wrote:quoted
+void fpregs_lock_and_load(void) +{ + /* + * fpregs_lock() only disables preemption (mostly). So modifying state + * in an interrupt could screw up some in progress fpregs operation, + * but appear to work. Warn about it.I don't like comments where it sounds like we don't know what we're doing. "Appear to work"?
I can change it. This patch started with the observation that modifying xstate from the kernel had been gotten wrong a couple times in the past, so that is what this is referencing. Since then, the fancy automatic solution got boiled down to this helper and a couple warnings.