[PATCH v2 07/12] x86/retpoline/checksum32: Convert assembler indirect jumps

From: Andi Kleen
Date: Wed Jan 03 2018 - 21:01:59 EST


From: Andi Kleen <ak@xxxxxxxxxxxxxxx>

Convert all indirect jumps in 32bit checksum assembler code to use
non speculative sequences.

Based on code from David Woodhouse and Tim Chen

Signed-off-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>
---
arch/x86/lib/checksum_32.S | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/arch/x86/lib/checksum_32.S b/arch/x86/lib/checksum_32.S
index 4d34bb548b41..d19862183d4b 100644
--- a/arch/x86/lib/checksum_32.S
+++ b/arch/x86/lib/checksum_32.S
@@ -29,6 +29,7 @@
#include <asm/errno.h>
#include <asm/asm.h>
#include <asm/export.h>
+#include <asm/jump-asm.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
+ NOSPEC_JMP %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
+ NOSPEC_JMP %ebx
1: addl $64,%esi
addl $64,%edi
SRC(movb -32(%edx),%bl) ; SRC(movb (%edx),%bl)
--
2.14.3