Convert all indirect jumps in 32bit checksum assembler code to use
non-speculative sequences when CONFIG_RETPOLINE is enabled.

Signed-off-by: David Woodhouse <d...@amazon.co.uk>
Signed-off-by: Thomas Gleixner <t...@linutronix.de>
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/1515508997-6154-10-git-send-email-d...@amazon.co.uk
---
 arch/x86/lib/checksum_32.S | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/arch/x86/lib/checksum_32.S b/arch/x86/lib/checksum_32.S
index 4d34bb5..46e71a7 100644
--- a/arch/x86/lib/checksum_32.S
+++ b/arch/x86/lib/checksum_32.S
@@ -29,7 +29,8 @@
 #include <asm/errno.h>
 #include <asm/asm.h>
 #include <asm/export.h>
-                               
+#include <asm/nospec-branch.h>
+
 /*
  * computes a partial checksum, e.g. for TCP/UDP fragments
  */
@@ -156,7 +157,7 @@ ENTRY(csum_partial)
        negl %ebx
        lea 45f(%ebx,%ebx,2), %ebx
        testl %esi, %esi
-       jmp *%ebx
+       JMP_NOSPEC %ebx
 
        # Handle 2-byte-aligned regions
 20:    addw (%esi), %ax
@@ -439,7 +440,7 @@ ENTRY(csum_partial_copy_generic)
        andl $-32,%edx
        lea 3f(%ebx,%ebx), %ebx
        testl %esi, %esi 
-       jmp *%ebx
+       JMP_NOSPEC %ebx
 1:     addl $64,%esi
        addl $64,%edi 
        SRC(movb -32(%edx),%bl) ; SRC(movb (%edx),%bl)
-- 
2.7.4

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