linux: vmalloc_sync_all() is not a no-op when running in PAE mode on Xen.

Also vmalloc_sync_all() is only defined for x86 architectures so make
use of it in driver code conditional on CONFIG_X86.
Signed-off-by: Keir Fraser <keir@xensource.com>

linux-2.6-xen-sparse/arch/i386/mm/fault-xen.c

@@ -731,7 +731,7 @@ do_sigbus:
 	force_sig_info_fault(SIGBUS, BUS_ADRERR, address, tsk);
 }
 
-#ifndef CONFIG_X86_PAE
+#if !HAVE_SHARED_KERNEL_PMD
 void vmalloc_sync_all(void)
 {
 	/*

linux-2.6-xen-sparse/drivers/xen/util.c

@@ -31,7 +31,9 @@ struct vm_struct *alloc_vm_area(unsigned long size)
 	}
 
 	/* Map page directories into every address space. */
+#ifdef CONFIG_X86
 	vmalloc_sync_all();
+#endif
 
 	return area;
 }

linux-2.6-xen-sparse/include/asm-i386/mach-xen/asm/pgtable-3level.h

@@ -180,6 +180,6 @@ static inline pmd_t pfn_pmd(unsigned long page_nr, pgprot_t pgprot)
 
 #define __pmd_free_tlb(tlb, x)		do { } while (0)
 
-#define vmalloc_sync_all() ((void)0)
+void vmalloc_sync_all(void);
 
 #endif /* _I386_PGTABLE_3LEVEL_H */