x86/entry: Fix build with older toolchains

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@citrix.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
(cherry picked from commit a9fa82500818a8d8ce5f2843f1577bd2c29d088e)

diff --git a/xen/arch/x86/x86_64/entry.S b/xen/arch/x86/x86_64/entry.S
index 9c256746baa4f9829c5b52900d51ac1653256981..1ecf900eee991054816951a311b4422cb5983cd2 100644 (file)
--- a/xen/arch/x86/x86_64/entry.S
+++ b/xen/arch/x86/x86_64/entry.S
@@ -643,7 +643,9 @@ ENTRY(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: