From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756030AbeEaSBO (ORCPT ); Thu, 31 May 2018 14:01:14 -0400 Received: from mga01.intel.com ([192.55.52.88]:18555 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755948AbeEaR7B (ORCPT ); Thu, 31 May 2018 13:59:01 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.49,463,1520924400"; d="scan'208";a="60725523" From: "Chang S. Bae" To: Andy Lutomirski , "H . Peter Anvin" , Thomas Gleixner , Ingo Molnar Cc: Andi Kleen , Dave Hansen , Markus T Metzger , "Ravi V . Shankar" , "Chang S . Bae" , linux-kernel@vger.kernel.org Subject: [PATCH V2 08/15] x86/fsgsbase/64: Add intrinsics/macros for FSGSBASE instructions Date: Thu, 31 May 2018 10:58:38 -0700 Message-Id: <1527789525-8857-9-git-send-email-chang.seok.bae@intel.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1527789525-8857-1-git-send-email-chang.seok.bae@intel.com> References: <1527789525-8857-1-git-send-email-chang.seok.bae@intel.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Andi Kleen Add C intrinsics and assembler macros for the new RD/WR FS/GS BASE instructions. Very straight forward. Used in followon patch. [luto: rename the variables from fs and gs to fsbase and gsbase and make fsgs.h safe to include on 32-bit kernels.] v2: Use __always_inline Signed-off-by: Andi Kleen Signed-off-by: Andy Lutomirski [chang: Replace new instruction macros with GAS-compatible and renaming. Note: if GCC supports it, we can add -mfsgsbase to CFLAGS and use the builtins here for extra performance.] Signed-off-by: Chang S. Bae Cc: H. Peter Anvin Cc: Dave Hansen Cc: Thomas Gleixner Cc: Ingo Molnar --- arch/x86/include/asm/fsgsbase.h | 70 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 70 insertions(+) diff --git a/arch/x86/include/asm/fsgsbase.h b/arch/x86/include/asm/fsgsbase.h index 0d4fbef..ed42015 100644 --- a/arch/x86/include/asm/fsgsbase.h +++ b/arch/x86/include/asm/fsgsbase.h @@ -18,6 +18,42 @@ unsigned long read_task_gsbase(struct task_struct *task); int write_task_fsbase(struct task_struct *task, unsigned long fsbase); int write_task_gsbase(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(".byte 0xf3, 0x48, 0x0f, 0xae, 0xc0 # rdfsbaseq %%rax" + : "=a" (fsbase) + :: "memory"); + return fsbase; +} + +static __always_inline unsigned long rdgsbase(void) +{ + unsigned long gsbase; + + asm volatile(".byte 0xf3, 0x48, 0x0f, 0xae, 0xc8 # rdgsbaseq %%rax;" + : "=a" (gsbase) + :: "memory"); + return gsbase; +} + +static __always_inline void wrfsbase(unsigned long fsbase) +{ + asm volatile(".byte 0xf3, 0x48, 0x0f, 0xae, 0xd0 # wrfsbaseq %%rax" + :: "a" (fsbase) + : "memory"); +} + +static __always_inline void wrgsbase(unsigned long gsbase) +{ + asm volatile(".byte 0xf3, 0x48, 0x0f, 0xae, 0xd8 # wrgsbaseq %%rax;" + :: "a" (gsbase) + : "memory"); +} + /* Helper functions for reading/writing FS/GS base */ static inline unsigned long read_fsbase(void) @@ -42,6 +78,40 @@ void write_inactive_gsbase(unsigned long gsbase); #endif /* CONFIG_X86_64 */ +#else /* __ASSEMBLY__ */ + +#ifdef CONFIG_X86_64 + +#include + +.macro RDGSBASE opd + REG_TYPE rdgsbase_opd_type \opd + .if rdgsbase_opd_type == REG_TYPE_R64 + R64_NUM rdgsbase_opd \opd + .byte 0xf3 + PFX_REX rdgsbase_opd 0 W = 1 + .else + .error "RDGSBASE: only for 64-bit value" + .endif + .byte 0xf, 0xae + MODRM 0xc0 rdgsbase_opd 1 +.endm + +.macro WRGSBASE opd + REG_TYPE wrgsbase_opd_type \opd + .if wrgsbase_opd_type == REG_TYPE_R64 + R64_NUM wrgsbase_opd \opd + .byte 0xf3 + PFX_REX wrgsbase_opd 0 W = 1 + .else + .error "WRGSBASE: only for 64-bit value" + .endif + .byte 0xf, 0xae + MODRM 0xd0 wrgsbase_opd 1 +.endm + +#endif /* CONFIG_X86_64 */ + #endif /* __ASSEMBLY__ */ #endif /* _ASM_FSGSBASE_H */ -- 2.7.4