From: Andy Lutomirski <luto@kernel.org>
To: x86@kernel.org, linux-kernel@vger.kernel.org
Cc: Borislav Petkov <bp@alien8.de>, Fenghua Yu <fenghua.yu@intel.com>,
Oleg Nesterov <oleg@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
Sai Praneeth Prakhya <sai.praneeth.prakhya@intel.com>,
yu-cheng yu <yu-cheng.yu@intel.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
Rik van Riel <riel@redhat.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Andy Lutomirski <luto@kernel.org>
Subject: [PATCH v2 4/5] x86/fpu: Speed up lazy FPU restores slightly
Date: Sun, 24 Jan 2016 14:38:09 -0800 [thread overview]
Message-ID: <980004297e233c27066d54e71382c44cdd36ef7c.1453675014.git.luto@kernel.org> (raw)
In-Reply-To: <cover.1453675014.git.luto@kernel.org>
In-Reply-To: <cover.1453675014.git.luto@kernel.org>
If we have an FPU, there's no need to check CR0 for FPU emulation.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
---
arch/x86/kernel/traps.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index 87f80febf477..36a9c017540e 100644
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -752,7 +752,7 @@ do_device_not_available(struct pt_regs *regs, long error_code)
RCU_LOCKDEP_WARN(!rcu_is_watching(), "entry code didn't wake RCU");
#ifdef CONFIG_MATH_EMULATION
- if (read_cr0() & X86_CR0_EM) {
+ if (!boot_cpu_has(X86_FEATURE_FPU) && (read_cr0() & X86_CR0_EM)) {
struct math_emu_info info = { };
conditional_sti(regs);
--
2.5.0
next prev parent reply other threads:[~2016-01-24 22:38 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-24 22:38 [PATCH v2 0/5] x86/fpu: eagerfpu fixes, speedups, and default enablement Andy Lutomirski
2016-01-24 22:38 ` [PATCH v2 1/5] x86/fpu: Fix math emulation in eager fpu mode Andy Lutomirski
2016-02-09 16:10 ` [tip:x86/fpu] " tip-bot for Andy Lutomirski
2016-01-24 22:38 ` [PATCH v2 2/5] x86/fpu: Fix FNSAVE usage in eagerfpu mode Andy Lutomirski
2016-01-25 15:40 ` Dave Hansen
2016-01-25 17:25 ` Andy Lutomirski
2016-01-25 17:26 ` Dave Hansen
2016-02-09 16:10 ` [tip:x86/fpu] " tip-bot for Andy Lutomirski
2016-01-24 22:38 ` [PATCH v2 3/5] x86/fpu: Fold fpu_copy into fpu__copy Andy Lutomirski
2016-02-09 16:10 ` [tip:x86/fpu] x86/fpu: Fold fpu_copy() into fpu__copy() tip-bot for Andy Lutomirski
2016-01-24 22:38 ` Andy Lutomirski [this message]
2016-02-09 16:11 ` [tip:x86/fpu] x86/fpu: Speed up lazy FPU restores slightly tip-bot for Andy Lutomirski
2016-01-24 22:38 ` [PATCH v2 5/5] x86/fpu: Default eagerfpu=on on all CPUs Andy Lutomirski
2016-02-09 16:11 ` [tip:x86/fpu] " tip-bot for Andy Lutomirski
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=980004297e233c27066d54e71382c44cdd36ef7c.1453675014.git.luto@kernel.org \
--to=luto@kernel.org \
--cc=bp@alien8.de \
--cc=dave.hansen@linux.intel.com \
--cc=fenghua.yu@intel.com \
--cc=linux-kernel@vger.kernel.org \
--cc=oleg@redhat.com \
--cc=peterz@infradead.org \
--cc=riel@redhat.com \
--cc=sai.praneeth.prakhya@intel.com \
--cc=torvalds@linux-foundation.org \
--cc=x86@kernel.org \
--cc=yu-cheng.yu@intel.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.