[Xen-devel] [PATCH v4 3/4] x86: fix indirect thunk usage of CONFIG_INDIRECT_THUNK

[Roger Pau Monne <roger.pau@xxxxxxxxxx>]

When indirect_thunk_asm.h is instantiated directly into assembly files
CONFIG_INDIRECT_THUNK might not be defined, and thus using .if against
it is wrong.

Add a check to define CONFIG_INDIRECT_THUNK to 0 if not defined, so
that using .if CONFIG_INDIRECT_THUNK is always correct.

This suppresses the following clang error:

<instantiation>:8:9: error: expected absolute expression
    .if CONFIG_INDIRECT_THUNK == 1
        ^
<instantiation>:1:1: note: while in macro instantiation
INDIRECT_BRANCH call %rdx
^
entry.S:589:9: note: while in macro instantiation
        INDIRECT_CALL %rdx
        ^

Signed-off-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
---
Cc: Jan Beulich <jbeulich@xxxxxxxx>
Cc: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
 xen/include/asm-x86/indirect_thunk_asm.h | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/xen/include/asm-x86/indirect_thunk_asm.h 
b/xen/include/asm-x86/indirect_thunk_asm.h
index 96bcc25497..ad83986b2d 100644
--- a/xen/include/asm-x86/indirect_thunk_asm.h
+++ b/xen/include/asm-x86/indirect_thunk_asm.h
@@ -3,6 +3,10 @@
  * usual #ifdef'ary to turn into comments.
  */
 
+.ifndef CONFIG_INDIRECT_THUNK
+    .equ CONFIG_INDIRECT_THUNK, 0
+.endif
+
 .macro INDIRECT_BRANCH insn:req arg:req
 /*
  * Create an indirect branch.  insn is one of call/jmp, arg is a single
-- 
2.16.1


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