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From: "Chang S. Bae" <chang.seok.bae@intel.com>
To: Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@kernel.org>, Andy Lutomirski <luto@kernel.org>,
	"H . Peter Anvin" <hpa@zytor.com>,
	Andi Kleen <ak@linux.intel.com>
Cc: Ravi Shankar <ravi.v.shankar@intel.com>,
	"Chang S . Bae" <chang.seok.bae@intel.com>,
	LKML <linux-kernel@vger.kernel.org>
Subject: [RESEND PATCH v6 03/12] x86/fsgsbase/64: Add intrinsics for FSGSBASE instructions
Date: Fri, 15 Mar 2019 13:06:36 -0700
Message-ID: <1552680405-5265-4-git-send-email-chang.seok.bae@intel.com> (raw)
In-Reply-To: <1552680405-5265-1-git-send-email-chang.seok.bae@intel.com>

From: Andi Kleen <ak@linux.intel.com>

Add C intrinsics and assembler macros for the new FSBASE and GSBASE
instructions.

Very straight forward. Used in followon patches.

[ luto: Rename the variables from FS and GS to FSBASE and GSBASE and
  make <asm/fsgsbase.h> safe to include on 32-bit kernels. ]

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Chang S. Bae <chang.seok.bae@intel.com>
Reviewed-by: Andy Lutomirski <luto@kernel.org>
Reviewed-by: Andi Kleen <ak@linux.intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
---
 arch/x86/include/asm/fsgsbase.h | 30 ++++++++++++++++++++++++++++++
 1 file changed, 30 insertions(+)

diff --git a/arch/x86/include/asm/fsgsbase.h b/arch/x86/include/asm/fsgsbase.h
index bca4c743de77..fdd1177499b4 100644
--- a/arch/x86/include/asm/fsgsbase.h
+++ b/arch/x86/include/asm/fsgsbase.h
@@ -19,6 +19,36 @@ extern unsigned long x86_gsbase_read_task(struct task_struct *task);
 extern void x86_fsbase_write_task(struct task_struct *task, unsigned long fsbase);
 extern void x86_gsbase_write_task(struct task_struct *task, unsigned long gsbase);
 
+/* Must be protected by X86_FEATURE_FSGSBASE check. */
+
+static __always_inline unsigned long rdfsbase(void)
+{
+	unsigned long fsbase;
+
+	asm volatile("rdfsbase %0" : "=r" (fsbase) :: "memory");
+
+	return fsbase;
+}
+
+static __always_inline unsigned long rdgsbase(void)
+{
+	unsigned long gsbase;
+
+	asm volatile("rdgsbase %0" : "=r" (gsbase) :: "memory");
+
+	return gsbase;
+}
+
+static __always_inline void wrfsbase(unsigned long fsbase)
+{
+	asm volatile("wrfsbase %0" :: "r" (fsbase) : "memory");
+}
+
+static __always_inline void wrgsbase(unsigned long gsbase)
+{
+	asm volatile("wrgsbase %0" :: "r" (gsbase) : "memory");
+}
+
 /* Helper functions for reading/writing FS/GS base */
 
 static inline unsigned long x86_fsbase_read_cpu(void)
-- 
2.19.1


  parent reply index

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-03-15 20:06 [RESEND PATCH v6 00/12] x86: Enable " Chang S. Bae
2019-03-15 20:06 ` [RESEND PATCH v6 01/12] x86/fsgsbase/64: Add 'unsafe_fsgsbase' to enable CR4.FSGSBASE Chang S. Bae
2019-03-15 20:06 ` [RESEND PATCH v6 02/12] kbuild: Raise the minimum required binutils version to 2.21 Chang S. Bae
2019-03-15 20:06 ` Chang S. Bae [this message]
2019-03-15 20:06 ` [RESEND PATCH v6 04/12] x86/fsgsbase/64: Enable FSGSBASE instructions in the helper functions Chang S. Bae
2019-03-25 11:38   ` Thomas Gleixner
2019-03-25 12:46     ` Thomas Gleixner
2019-03-25 13:05       ` Thomas Gleixner
2019-03-26  0:38     ` Andi Kleen
2019-03-26 15:01       ` New feature/ABI review process [was Re: [RESEND PATCH v6 04/12] x86/fsgsbase/64:..] Thomas Gleixner
2019-03-26 22:56         ` Andi Kleen
2019-03-27 21:15           ` Thomas Gleixner
2019-03-15 20:06 ` [RESEND PATCH v6 05/12] x86/fsgsbase/64: Preserve FS/GS state in __switch_to() if FSGSBASE is on Chang S. Bae
2019-03-15 20:06 ` [RESEND PATCH v6 06/12] x86/fsgsbase/64: When copying a thread, use the FSGSBASE instructions if available Chang S. Bae
2019-03-15 20:06 ` [RESEND PATCH v6 07/12] x86/fsgsbase/64: Introduce the FIND_PERCPU_BASE macro Chang S. Bae
2019-03-25  9:02   ` Thomas Gleixner
2019-05-01 13:52     ` Bae, Chang Seok
2019-03-15 20:06 ` [RESEND PATCH v6 08/12] x86/fsgsbase/64: Use the per-CPU base as GSBASE at the paranoid_entry Chang S. Bae
2019-03-25  9:44   ` Thomas Gleixner
2019-04-05  8:35     ` Thomas Gleixner
2019-04-05 13:50       ` Andy Lutomirski
2019-05-01 13:52         ` Bae, Chang Seok
2019-05-01 17:40           ` Andy Lutomirski
2019-05-01 18:01             ` Bae, Chang Seok
     [not found]               ` <7029A32B-958E-4C1E-8B5F-D49BA68E4755@intel.com>
2019-05-01 20:25                 ` Andy Lutomirski
2019-05-01 21:04                   ` Bae, Chang Seok
2019-05-02  0:29                     ` Andy Lutomirski
2019-05-06 22:56     ` Bae, Chang Seok
2019-03-15 20:06 ` [RESEND PATCH v6 09/12] selftests/x86/fsgsbase: Test WRGSBASE Chang S. Bae
2019-03-15 20:06 ` [RESEND PATCH v6 10/12] x86/fsgsbase/64: Enable FSGSBASE by default and add a chicken bit Chang S. Bae
2019-03-15 20:06 ` [RESEND PATCH v6 11/12] x86/elf: Enumerate kernel FSGSBASE capability in AT_HWCAP2 Chang S. Bae
2019-03-15 20:06 ` [RESEND PATCH v6 12/12] x86/fsgsbase/64: Add documentation for FSGSBASE Chang S. Bae
2019-03-30 16:15   ` Randy Dunlap
2019-03-26  0:43 ` [RESEND PATCH v6 00/12] x86: Enable FSGSBASE instructions Andy Lutomirski

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