LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
From: "Chang S. Bae" <chang.seok.bae@intel.com>
To: Andy Lutomirski <luto@kernel.org>,
	"H . Peter Anvin" <hpa@zytor.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@kernel.org>
Cc: Andi Kleen <ak@linux.intel.com>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	Markus T Metzger <markus.t.metzger@intel.com>,
	"Ravi V . Shankar" <ravi.v.shankar@intel.com>,
	"Chang S . Bae" <chang.seok.bae@intel.com>,
	LKML <linux-kernel@vger.kernel.org>
Subject: [PATCH v3 4/7] x86/fsgsbase/64: Factor out load FS/GS segments from __switch_to
Date: Thu,  7 Jun 2018 10:06:05 -0700	[thread overview]
Message-ID: <1528391168-22224-5-git-send-email-chang.seok.bae@intel.com> (raw)
In-Reply-To: <1528391168-22224-1-git-send-email-chang.seok.bae@intel.com>

Instead of open code, load_fsgs() will cleanup __switch_to
and symmetric with FS/GS segment save. When FSGSBASE
enabled, X86_FEATURE_FSGSBASE check will be incorporated.

Signed-off-by: Chang S. Bae <chang.seok.bae@intel.com>
Reviewed-by: Andi Kleen <ak@linux.intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Andy Lutomirski <luto@kernel.org>
---
 arch/x86/kernel/process_64.c | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index e498671..cebf240 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -279,6 +279,15 @@ static __always_inline void load_seg_legacy(unsigned short prev_index,
 	}
 }
 
+static __always_inline void load_fsgs(struct thread_struct *prev,
+				      struct thread_struct *next)
+{
+	load_seg_legacy(prev->fsindex, prev->fsbase,
+			next->fsindex, next->fsbase, FS);
+	load_seg_legacy(prev->gsindex, prev->gsbase,
+			next->gsindex, next->gsbase, GS);
+}
+
 static unsigned long task_seg_base(struct task_struct *task,
 				   unsigned short selector)
 {
@@ -588,10 +597,7 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p)
 	if (unlikely(next->ds | prev->ds))
 		loadsegment(ds, next->ds);
 
-	load_seg_legacy(prev->fsindex, prev->fsbase,
-			next->fsindex, next->fsbase, FS);
-	load_seg_legacy(prev->gsindex, prev->gsbase,
-			next->gsindex, next->gsbase, GS);
+	load_fsgs(prev, next);
 
 	switch_fpu_finish(next_fpu, cpu);
 
-- 
2.7.4

  parent reply	other threads:[~2018-06-07 17:07 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-06-07 17:06 [PATCH v3 0/7] x86: infrastructure to enable FSGSBASE Chang S. Bae
2018-06-07 17:06 ` [PATCH v3 1/7] x86/fsgsbase/64: Introduce FS/GS base helper functions Chang S. Bae
2018-06-07 17:06 ` [PATCH v3 2/7] x86/fsgsbase/64: Make ptrace read FS/GS base accurately Chang S. Bae
2018-06-07 17:06 ` [PATCH v3 3/7] x86/fsgsbase/64: Use FS/GS base helpers in core dump Chang S. Bae
2018-06-07 17:06 ` Chang S. Bae [this message]
2018-06-18 22:06   ` [PATCH v3 4/7] x86/fsgsbase/64: Factor out load FS/GS segments from __switch_to Andy Lutomirski
2018-06-07 17:06 ` [PATCH v3 5/7] x86/segments/64: Rename PER_CPU segment to CPU_NUMBER Chang S. Bae
2018-06-07 17:06 ` [PATCH v3 6/7] x86/vdso: Introduce CPU number helper functions Chang S. Bae
2018-06-18 22:07   ` Andy Lutomirski
2018-06-07 17:06 ` [PATCH v3 7/7] x86/vdso: Move out the CPU number store Chang S. Bae
2018-06-18 22:08   ` Andy Lutomirski
2018-06-18 23:12     ` Bae, Chang Seok

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=1528391168-22224-5-git-send-email-chang.seok.bae@intel.com \
    --to=chang.seok.bae@intel.com \
    --cc=ak@linux.intel.com \
    --cc=dave.hansen@linux.intel.com \
    --cc=hpa@zytor.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=luto@kernel.org \
    --cc=markus.t.metzger@intel.com \
    --cc=mingo@kernel.org \
    --cc=ravi.v.shankar@intel.com \
    --cc=tglx@linutronix.de \
    --subject='Re: [PATCH v3 4/7] x86/fsgsbase/64: Factor out load FS/GS segments from __switch_to' \
    /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

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).