Re: [PATCH v8 03/27] x86/fpu/xstate: Change names to separate XSAVES system and user states
flat view
From: Borislav Petkov <bp@alien8.de>
Date: 2019-08-21 14:45:46
Also in:
linux-arch, linux-doc, linux-mm, lkml
On Tue, Aug 13, 2019 at 01:52:01PM -0700, Yu-cheng Yu wrote:
Control-flow Enforcement (CET) MSR contents are XSAVES system states. To support CET, introduce XSAVES system states first. XSAVES is a "supervisor" instruction and, comparing to XSAVE, saves additional "supervisor" states that can be modified only from CPL 0. However, these states are per-task and not kernel's own. Rename "supervisor" states to "system" states to clearly separate them from "user" states. Signed-off-by: Yu-cheng Yu <redacted> --- arch/x86/include/asm/fpu/internal.h | 4 +- arch/x86/include/asm/fpu/xstate.h | 20 +++---- arch/x86/kernel/fpu/init.c | 2 +- arch/x86/kernel/fpu/signal.c | 10 ++-- arch/x86/kernel/fpu/xstate.c | 86 ++++++++++++++--------------- 5 files changed, 60 insertions(+), 62 deletions(-)
...
quoted hunk ↗ jump to hunk
diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c index e5cb67d67c03..d560e8861a3c 100644 --- a/arch/x86/kernel/fpu/xstate.c +++ b/arch/x86/kernel/fpu/xstate.c@@ -54,13 +54,16 @@ static short xsave_cpuid_features[] __initdata = { }; /* - * Mask of xstate features supported by the CPU and the kernel: + * XSAVES system states can only be modified from CPL 0 and saved by + * XSAVES. The rest are user states. The following is a mask of + * supported user state features derived from boot_cpu_has() and
...derived from detected CPUID feature flags and
SUPPORTED_XFEATURES_MASK.
--
Regards/Gruss,
Boris.
Good mailing practices for 400: avoid top-posting and trim the reply.