Commit-ID:  8081a6f40dc2f74d40424addf2f5a63c5b85107b
Gitweb:     https://git.kernel.org/tip/8081a6f40dc2f74d40424addf2f5a63c5b85107b
Author:     David Woodhouse <d...@amazon.co.uk>
AuthorDate: Tue, 9 Jan 2018 14:43:14 +0000
Committer:  Thomas Gleixner <t...@linutronix.de>
CommitDate: Tue, 9 Jan 2018 16:17:54 +0100

x86/retpoline/xen: Convert Xen hypercall indirect jumps

Convert indirect call in Xen hypercall to use non-speculative sequence,
when CONFIG_RETPOLINE is enabled.

Signed-off-by: David Woodhouse <d...@amazon.co.uk>
Signed-off-by: Thomas Gleixner <t...@linutronix.de>
Reviewed-by: Juergen Gross <jgr...@suse.com>
Acked-by: Arjan van de Ven <ar...@linux.intel.com>
Acked-by: Ingo Molnar <mi...@kernel.org>
Cc: gno...@lxorguk.ukuu.org.uk
Cc: Rik van Riel <r...@redhat.com>
Cc: Andi Kleen <a...@linux.intel.com>
Cc: Peter Zijlstra <pet...@infradead.org>
Cc: Linus Torvalds <torva...@linux-foundation.org>
Cc: Jiri Kosina <ji...@kernel.org>
Cc: Andy Lutomirski <l...@amacapital.net>
Cc: Dave Hansen <dave.han...@intel.com>
Cc: Kees Cook <keesc...@google.com>
Cc: Tim Chen <tim.c.c...@linux.intel.com>
Cc: Greg Kroah-Hartman <gre...@linux-foundation.org>
Cc: Paul Turner <p...@google.com>
Link: 
https://lkml.kernel.org/r/1515508997-6154-9-git-send-email-d...@amazon.co.uk

---
 arch/x86/include/asm/xen/hypercall.h | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/arch/x86/include/asm/xen/hypercall.h 
b/arch/x86/include/asm/xen/hypercall.h
index 7cb282e..bfd8826 100644
--- a/arch/x86/include/asm/xen/hypercall.h
+++ b/arch/x86/include/asm/xen/hypercall.h
@@ -44,6 +44,7 @@
 #include <asm/page.h>
 #include <asm/pgtable.h>
 #include <asm/smap.h>
+#include <asm/nospec-branch.h>
 
 #include <xen/interface/xen.h>
 #include <xen/interface/sched.h>
@@ -217,9 +218,9 @@ privcmd_call(unsigned call,
        __HYPERCALL_5ARG(a1, a2, a3, a4, a5);
 
        stac();
-       asm volatile("call *%[call]"
+       asm volatile(CALL_NOSPEC
                     : __HYPERCALL_5PARAM
-                    : [call] "a" (&hypercall_page[call])
+                    : [thunk_target] "a" (&hypercall_page[call])
                     : __HYPERCALL_CLOBBER5);
        clac();
 

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