[PATCH] x86/entry: Fix build with older toolchains

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

Binutils older than 2.29 doesn't know INCSSPD.

Fixes: 8e186f98ce0e ("x86: Use indirect calls in reset-stack infrastructure")
Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
CC: Jan Beulich <JBeulich@xxxxxxxx>
CC: Roger Pau Monné <roger.pau@xxxxxxxxxx>
---
 xen/arch/x86/x86_64/entry.S | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/xen/arch/x86/x86_64/entry.S b/xen/arch/x86/x86_64/entry.S
index 461bbc355872..a4615e1ccbaf 100644
--- a/xen/arch/x86/x86_64/entry.S
+++ b/xen/arch/x86/x86_64/entry.S
@@ -650,7 +650,9 @@ FUNC(continue_pv_domain)
          * JMPed to.  Drop the return address.
          */
         add   $8, %rsp
+#ifdef CONFIG_XEN_SHSTK
         ALTERNATIVE "", "mov $2, %eax; incsspd %eax", X86_FEATURE_XEN_SHSTK
+#endif
 
         call  check_wakeup_from_wait
 ret_from_intr:

base-commit: d5887c0decbd90e798b24ed696628645b04632fb
-- 
2.30.2