hvmloader: Fix _start-relative calculation of hypercall page address.

We got away with it because _start-HYPERCALL_PHYSICAL_ADDRESS happens
to equal HYPERCALL_PHYSICAL_ADDRESS.

Signed-off-by: Keir Fraser <keir@xen.org>
xen-unstable changeset:   23244:024b06de81ca
xen-unstable date:        Mon Apr 18 18:08:47 2011 +0100

tools/firmware/hvmloader/config.h

@@ -41,6 +41,7 @@ extern unsigned long pci_mem_start, pci_mem_end;
 #define SMBIOS_PHYSICAL_ADDRESS       0x000EB000
 #define SMBIOS_MAXIMUM_SIZE           0x00005000
 #define ROMBIOS_PHYSICAL_ADDRESS      0x000F0000
+#define HVMLOADER_PHYSICAL_ADDRESS    0x00100000
 
 /* Offsets from E820_PHYSICAL_ADDRESS. */
 #define E820_NR_OFFSET                0x0

tools/firmware/hvmloader/hypercall.h

@@ -39,7 +39,8 @@
  * NB. Hypercall address needs to be relative to a linkage symbol for
  * some version of ld to relocate the relative calls properly.
  */
-#define hypercall_pa "_start - " STR(HYPERCALL_PHYSICAL_ADDRESS)
+#define hypercall_pa "_start - " STR(HVMLOADER_PHYSICAL_ADDRESS) \
+                           " + " STR(HYPERCALL_PHYSICAL_ADDRESS)
 
 #define _hypercall0(type, name)						\
 ({									\