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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 4/6] x86/fsgsbase/64: Factor out load FS/GS segments from __switch_to
Date: Mon,  4 Jun 2018 12:24:27 -0700	[thread overview]
Message-ID: <1528140269-26205-5-git-send-email-chang.seok.bae@intel.com> (raw)
In-Reply-To: <1528140269-26205-1-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: Andy Lutomirski <luto@kernel.org>
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:[~2018-06-04 19:24 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-06-04 19:24 [PATCH 0/6] x86: infrastructure to enable FSGSBASE Chang S. Bae
2018-06-04 19:24 ` [PATCH 1/6] x86/fsgsbase/64: Introduce FS/GS base helper functions Chang S. Bae
2018-06-04 19:24 ` [PATCH 2/6] x86/fsgsbase/64: Make ptrace read FS/GS base accurately Chang S. Bae
2018-06-04 19:24 ` [PATCH 3/6] x86/fsgsbase/64: Use FS/GS base helpers in core dump Chang S. Bae
2018-06-04 19:24 ` Chang S. Bae [this message]
2018-06-04 19:24 ` [PATCH 5/6] x86/msr: write_rdtscp_aux() to use wrmsr_safe() Chang S. Bae
2018-06-04 19:24 ` [PATCH 6/6] x86/vdso: Move out the CPU number store Chang S. Bae
2018-06-05  3:57   ` Mika Penttilä
2018-06-05  4:44     ` Bae, Chang Seok
2018-06-05  5:19       ` Mika Penttilä
2018-06-05  5:36     ` H. Peter Anvin
2018-06-05  6:03       ` Mika Penttilä
2018-06-05 10:22       ` Andy Lutomirski
2018-06-13  6:53   ` [lkp-robot] [x86/vdso] ab1bcc4420: BUG:kernel_hang_in_boot_stage kernel test robot

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