From: Yu-cheng Yu <yu-cheng.yu@intel.com>
To: linux-kernel@vger.kernel.org, x86@kernel.org,
"H. Peter Anvin" <hpa@zytor.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
Tony Luck <tony.luck@intel.com>,
Andy Lutomirski <luto@kernel.org>, Borislav Petkov <bp@alien8.de>,
Rik van Riel <riel@surriel.com>,
"Ravi V. Shankar" <ravi.v.shankar@intel.com>,
Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
Fenghua Yu <fenghua.yu@intel.com>,
Peter Zijlstra <peterz@infradead.org>
Cc: Yu-cheng Yu <yu-cheng.yu@intel.com>
Subject: [PATCH 3/3] x86/fpu/xstate: WARN_ONCE on checking alignment of disabled xfeatures
Date: Thu, 9 Jan 2020 13:14:52 -0800 [thread overview]
Message-ID: <20200109211452.27369-4-yu-cheng.yu@intel.com> (raw)
In-Reply-To: <20200109211452.27369-1-yu-cheng.yu@intel.com>
An XSAVES component's alignment/offset is meaningful only when the feature
is enabled. Return zero and WARN_ONCE on checking alignment of disabled
features.
Signed-off-by: Yu-cheng Yu <yu-cheng.yu@intel.com>
Reviewed-by: Dave Hansen <dave.hansen@linux.intel.com>
---
arch/x86/kernel/fpu/xstate.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c
index 73314e8fce02..4fa494073289 100644
--- a/arch/x86/kernel/fpu/xstate.c
+++ b/arch/x86/kernel/fpu/xstate.c
@@ -330,6 +330,13 @@ static int xfeature_is_aligned(int xfeature_nr)
u32 eax, ebx, ecx, edx;
CHECK_XFEATURE(xfeature_nr);
+
+ if (!xfeature_enabled(xfeature_nr)) {
+ WARN_ONCE(1, "Checking alignment of disabled xfeature %d\n",
+ xfeature_nr);
+ return 0;
+ }
+
cpuid_count(XSTATE_CPUID, xfeature_nr, &eax, &ebx, &ecx, &edx);
/*
* The value returned by ECX[1] indicates the alignment
--
2.21.0
next prev parent reply other threads:[~2020-01-09 21:17 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-09 21:14 [PATCH 0/3] Fix two issues in XSAVES offset calculation Yu-cheng Yu
2020-01-09 21:14 ` [PATCH 1/3] x86/fpu/xstate: Fix last_good_offset in setup_xstate_features() Yu-cheng Yu
2020-02-11 18:56 ` Borislav Petkov
2020-02-12 14:50 ` [tip: x86/fpu] " tip-bot2 for Yu-cheng Yu
2020-01-09 21:14 ` [PATCH 2/3] x86/fpu/xstate: Fix XSAVES offsets in setup_xstate_comp() Yu-cheng Yu
2020-02-12 14:50 ` [tip: x86/fpu] " tip-bot2 for Yu-cheng Yu
2020-01-09 21:14 ` Yu-cheng Yu [this message]
2020-02-12 14:50 ` [tip: x86/fpu] x86/fpu/xstate: Warn when checking alignment of disabled xfeatures tip-bot2 for Yu-cheng Yu
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