[PATCH 4/6] x86/alternatives: Add an auxilary section

From	Borislav Petkov <bp@alien8.de>
Newsgroups	linux.kernel
Subject	[PATCH 4/6] x86/alternatives: Add an auxilary section
Date	2016-01-24 10:40 +0100
Message-ID	<qUpjk-2Lg-9@gated-at.bofh.it> (permalink)
References	<qUpjj-2Lg-3@gated-at.bofh.it>
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From: Borislav Petkov <bp@suse.de>

Add .altinstr_aux for additional instructions which will be used before
and/or during patching. All stuff which needs more sophisticated
patching should go there. See next patch.

Signed-off-by: Borislav Petkov <bp@suse.de>
---
 arch/x86/kernel/vmlinux.lds.S | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S
index 4f1994257a18..04afe9b7e52a 100644
--- a/arch/x86/kernel/vmlinux.lds.S
+++ b/arch/x86/kernel/vmlinux.lds.S
@@ -195,6 +195,17 @@ SECTIONS
 	:init
 #endif
 
+	/*
+	 * Section for code used exclusively before alternatives are run. All
+	 * references to such code must be patched out by alternatives, normally
+	 * by using X86_FEATURE_ALWAYS CPU feature bit.
+	 *
+	 * See static_cpu_has() for an example.
+	 */
+	.altinstr_aux : AT(ADDR(.altinstr_aux) - LOAD_OFFSET) {
+		*(.altinstr_aux)
+	}
+
 	INIT_DATA_SECTION(16)
 
 	.x86_cpu_dev.init : AT(ADDR(.x86_cpu_dev.init) - LOAD_OFFSET) {
-- 
2.3.5

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[PATCH 4/6] x86/alternatives: Add an auxilary section Borislav Petkov <bp@alien8.de> - 2016-01-24 10:40 +0100

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