xen/virtual-region: Drop setup_virtual_regions()

All other actions it used to perform have been converted to build-time
initialisation.  The extable setup can done at build time too.

This is one fewer setup step required to get exceptions working.

Take the opportunity to move 'core' into read_mostly, where it probably should
have lived all along.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Luca Fancellu <luca.fancellu@arm.com>
Tested-by: Luca Fancellu <luca.fancellu@arm.com>

xen/arch/arm/setup.c

@@ -719,7 +719,6 @@ void asmlinkage __init start_xen(unsigned long boot_phys_offset,
     percpu_init_areas();
     set_processor_id(0); /* needed early, for smp_processor_id() */
 
-    setup_virtual_regions(NULL, NULL);
     /* Initialize traps early allow us to get backtrace when an error occurred */
     init_traps();
 

xen/arch/x86/setup.c

@@ -1014,8 +1014,6 @@ void asmlinkage __init noreturn __start_xen(unsigned long mbi_p)
     smp_prepare_boot_cpu();
     sort_exception_tables();
 
-    setup_virtual_regions(__start___ex_table, __stop___ex_table);
-
     /* Full exception support from here on in. */
 
     rdmsrl(MSR_EFER, this_cpu(efer));

xen/common/virtual_region.c

@@ -26,7 +26,7 @@ static struct virtual_region core, core_init;
 #define LIST_ENTRY_CORE() { .next = &core_init.list,      .prev = &virtual_region_list }
 #define LIST_ENTRY_INIT() { .next = &virtual_region_list, .prev = &core.list }
 
-static struct virtual_region core = {
+static struct virtual_region core __read_mostly = {
     .list = LIST_ENTRY_CORE(),
     .text_start = _stext,
     .text_end = _etext,
@@ -39,6 +39,11 @@ static struct virtual_region core = {
         { __start_bug_frames_2, __stop_bug_frames_2 },
         { __start_bug_frames_3, __stop_bug_frames_3 },
     },
+
+#ifdef CONFIG_HAS_EX_TABLE
+    .ex = __start___ex_table,
+    .ex_end = __stop___ex_table,
+#endif
 };
 
 /* Becomes irrelevant when __init sections are cleared. */
@@ -53,6 +58,11 @@ static struct virtual_region core_init __initdata = {
         { __start_bug_frames_2, __stop_bug_frames_2 },
         { __start_bug_frames_3, __stop_bug_frames_3 },
     },
+
+#ifdef CONFIG_HAS_EX_TABLE
+    .ex = __start___ex_table,
+    .ex_end = __stop___ex_table,
+#endif
 };
 
 /*
@@ -161,13 +171,6 @@ void __init unregister_init_virtual_region(void)
     remove_virtual_region(&core_init);
 }
 
-void __init setup_virtual_regions(const struct exception_table_entry *start,
-                                  const struct exception_table_entry *end)
-{
-    core_init.ex = core.ex = start;
-    core_init.ex_end = core.ex_end = end;
-}
-
 /*
  * Local variables:
  * mode: C

xen/include/xen/virtual_region.h

@@ -32,13 +32,13 @@ struct virtual_region
         const struct bug_frame *start, *stop; /* Pointers to array of bug frames. */
     } frame[BUGFRAME_NR];
 
+#ifdef CONFIG_HAS_EX_TABLE
     const struct exception_table_entry *ex;
     const struct exception_table_entry *ex_end;
+#endif
 };
 
 const struct virtual_region *find_text_region(unsigned long addr);
-void setup_virtual_regions(const struct exception_table_entry *start,
-                           const struct exception_table_entry *end);
 void unregister_init_virtual_region(void);
 void register_virtual_region(struct virtual_region *r);
 void unregister_virtual_region(struct virtual_region *r);