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        Peter Zijlstra <peterz@infradead.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@kernel.org>,
        "Srivatsa S. Bhat" <srivatsa@csail.mit.edu>,
        "Matt Helsley (VMware)" <matt.helsley@gmail.com>,
        Alexey Makhalov <amakhalov@vmware.com>,
        Bo Gan <ganb@vmware.com>
Subject: [PATCH 4.4 25/43] x86/alternatives: Add an auxilary section
Date: Mon, 16 Jul 2018 09:36:30 +0200
Message-Id: <20180716073514.609955270@linuxfoundation.org>
In-Reply-To: <20180716073511.796555857@linuxfoundation.org>
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4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Borislav Petkov <bp@suse.de>

commit 337e4cc84021212a87b04b77b65cccc49304909e upstream

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>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1453842730-28463-8-git-send-email-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Srivatsa S. Bhat <srivatsa@csail.mit.edu>
Reviewed-by: Matt Helsley (VMware) <matt.helsley@gmail.com>
Reviewed-by: Alexey Makhalov <amakhalov@vmware.com>
Reviewed-by: Bo Gan <ganb@vmware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

 arch/x86/kernel/vmlinux.lds.S |   11 +++++++++++
 1 file changed, 11 insertions(+)

--- a/arch/x86/kernel/vmlinux.lds.S
+++ b/arch/x86/kernel/vmlinux.lds.S
@@ -202,6 +202,17 @@ 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) {