From: kaf24@firebug.cl.cam.ac.uk <kaf24@firebug.cl.cam.ac.uk>
Date: Mon, 10 Apr 2006 16:32:30 +0000 (+0100)
Subject: Fail the build if NR_hypercalls is not a power of two.
X-Git-Tag: archive/raspbian/4.8.0-1+rpi1~1^2~16158^2~7^2
X-Git-Url: https://dgit.raspbian.org/%22http://www.example.com/cgi/success//%22http:/www.example.com/cgi/success/?a=commitdiff_plain;h=7ddc2369b20e6b9e4f067585d8c7389b33b00abb;p=xen.git

Fail the build if NR_hypercalls is not a power of two.
Making this requirement clearer originally suggested by
Muli Ben Yehuda.

Signed-off-by: Keir Fraser <keir@xensource.com>
---

diff --git a/xen/include/asm-x86/config.h b/xen/include/asm-x86/config.h
index 23aabeb2b9..35efb1ba63 100644
--- a/xen/include/asm-x86/config.h
+++ b/xen/include/asm-x86/config.h
@@ -65,8 +65,13 @@
 
 #define barrier() __asm__ __volatile__("": : :"memory")
 
+/* A power-of-two value greater than or equal to number of hypercalls. */
 #define NR_hypercalls 32
 
+#if NR_hypercalls & (NR_hypercalls - 1)
+#error "NR_hypercalls must be a power-of-two value"
+#endif
+
 #ifndef NDEBUG
 #define MEMORY_GUARD
 #ifdef __x86_64__