linux-kernel - [PATCH 3/8] x86: Add intrinsics/macros for new rd/wr fs/gs base instructions

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <1413349911-3620-3-git-send-email-andi@firstfloor.org>
Date:	Tue, 14 Oct 2014 22:11:46 -0700
From:	Andi Kleen <andi@...stfloor.org>
To:	linux-kernel@...r.kernel.org
Cc:	x86@...nel.org, Andi Kleen <ak@...ux.intel.com>
Subject: [PATCH 3/8] x86: Add intrinsics/macros for new rd/wr fs/gs base instructions

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

Add C intrinsics and assembler macros for the new rd/wr fs/gs base
instructions and for swapgs.

Very straight forward. Used in followon patch.

For assembler only a few standard registers used by entry_64.S
are defined.

Signed-off-by: Andi Kleen <ak@...ux.intel.com>
---
 arch/x86/include/asm/fsgs.h | 54 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 54 insertions(+)
 create mode 100644 arch/x86/include/asm/fsgs.h

diff --git a/arch/x86/include/asm/fsgs.h b/arch/x86/include/asm/fsgs.h
new file mode 100644
index 0000000..1df5085
--- /dev/null
+++ b/arch/x86/include/asm/fsgs.h
@@ -0,0 +1,54 @@
+#ifndef _ASM_FSGS_H
+#define _ASM_FSGS_H 1
+
+#ifndef __ASSEMBLY__
+
+static inline void swapgs(void)
+{
+	asm volatile("swapgs" ::: "memory");
+}
+
+/* Must be protected by X86_FEATURE_FSGSBASE check. */
+
+static inline unsigned long rdgsbase(void)
+{
+	unsigned long gs;
+	asm volatile(".byte 0xf3,0x48,0x0f,0xae,0xc8 # rdgsbaseq %%rax"
+			: "=a" (gs)
+			:: "memory");
+	return gs;
+}
+
+static inline unsigned long rdfsbase(void)
+{
+	unsigned long fs;
+	asm volatile(".byte 0xf3,0x48,0x0f,0xae,0xc0 # rdfsbaseq %%rax"
+			: "=a" (fs)
+			:: "memory");
+	return fs;
+}
+
+static inline void wrgsbase(unsigned long gs)
+{
+	asm volatile(".byte 0xf3,0x48,0x0f,0xae,0xd8 # wrgsbaseq %%rax"
+			:: "a" (gs)
+			: "memory");
+}
+
+static inline void wrfsbase(unsigned long fs)
+{
+	asm volatile(".byte 0xf3,0x48,0x0f,0xae,0xd0 # wrfsbaseq %%rax"
+			:: "a" (fs)
+			: "memory");
+}
+
+#else
+
+/* Handle old assemblers. */
+#define RDGSBASE_R15 .byte 0xf3,0x49,0x0f,0xae,0xcf
+#define WRGSBASE_RDI .byte 0xf3,0x48,0x0f,0xae,0xdf
+#define WRGSBASE_R15 .byte 0xf3,0x49,0x0f,0xae,0xdf
+
+#endif /* __ASSEMBLY__ */
+
+#endif
-- 
1.9.3

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/