linux-kernel - [tip:x86/fpu] x86/fpu: Fix "x86/fpu: Legacy x87 FPU detected" message

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Date:   Wed, 25 Jan 2017 03:42:01 -0800
From:   tip-bot for Andy Lutomirski <tipbot@...or.com>
To:     linux-tip-commits@...r.kernel.org
Cc:     tedheadster@...il.com, riel@...hat.com, gnomes@...rguk.ukuu.org.uk,
        fenghua.yu@...el.com, mingo@...nel.org, luto@...nel.org,
        torvalds@...ux-foundation.org, hpa@...or.com,
        yu-cheng.yu@...el.com, peterz@...radead.org, bp@...e.de,
        bp@...en8.de, brgerst@...il.com, oleg@...hat.com,
        linux-kernel@...r.kernel.org, dave.hansen@...ux.intel.com,
        tglx@...utronix.de
Subject: [tip:x86/fpu] x86/fpu: Fix "x86/fpu: Legacy x87 FPU detected"
 message

Commit-ID:  9170fb409437b246078bcad3f1481d32dfe2ca28
Gitweb:     http://git.kernel.org/tip/9170fb409437b246078bcad3f1481d32dfe2ca28
Author:     Andy Lutomirski <luto@...nel.org>
AuthorDate: Wed, 18 Jan 2017 11:15:40 -0800
Committer:  Ingo Molnar <mingo@...nel.org>
CommitDate: Wed, 25 Jan 2017 10:12:42 +0100

x86/fpu: Fix "x86/fpu: Legacy x87 FPU detected" message

That message isn't at all clear -- what does "Legacy x87" even mean?

Clarify it.  If there's no FPU, say:

  x86/fpu: No FPU detected

If there's an FPU that doesn't have XSAVE, say:

  x86/fpu: x87 FPU will use FSAVE|FXSAVE

Signed-off-by: Andy Lutomirski <luto@...nel.org>
Reviewed-by: Borislav Petkov <bp@...e.de>
Cc: Borislav Petkov <bp@...en8.de>
Cc: Brian Gerst <brgerst@...il.com>
Cc: Dave Hansen <dave.hansen@...ux.intel.com>
Cc: Fenghua Yu <fenghua.yu@...el.com>
Cc: H. Peter Anvin <hpa@...or.com>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Matthew Whitehead <tedheadster@...il.com>
Cc: Oleg Nesterov <oleg@...hat.com>
Cc: One Thousand Gnomes <gnomes@...rguk.ukuu.org.uk>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Rik van Riel <riel@...hat.com>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: Yu-cheng Yu <yu-cheng.yu@...el.com>
Link: http://lkml.kernel.org/r/bb839385e18e27bca23fe8666dfdad8170473045.1484705016.git.luto@kernel.org
[ Small tweaks to the messages. ]
Signed-off-by: Ingo Molnar <mingo@...nel.org>
---
 arch/x86/kernel/fpu/xstate.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c
index 1d77704..96002f1 100644
--- a/arch/x86/kernel/fpu/xstate.c
+++ b/arch/x86/kernel/fpu/xstate.c
@@ -705,8 +705,14 @@ void __init fpu__init_system_xstate(void)
 	WARN_ON_FPU(!on_boot_cpu);
 	on_boot_cpu = 0;
 
+	if (!boot_cpu_has(X86_FEATURE_FPU)) {
+		pr_info("x86/fpu: No FPU detected\n");
+		return;
+	}
+
 	if (!boot_cpu_has(X86_FEATURE_XSAVE)) {
-		pr_info("x86/fpu: Legacy x87 FPU detected.\n");
+		pr_info("x86/fpu: x87 FPU will use %s\n",
+			boot_cpu_has(X86_FEATURE_FXSR) ? "FXSAVE" : "FSAVE");
 		return;
 	}