util: move qemu_real_host_page_size/mask to osdep.h

These only depend on the host and therefore belong in the common
osdep, not in a target-dependent object.

While at it, query the host during an init constructor, which guarantees
the page size will be well-defined throughout the execution of the program.

Suggested-by: Richard Henderson <rth@twiddle.net>
Reviewed-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Emilio G. Cota <cota@braap.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

exec.c

@@ -120,8 +120,6 @@ int use_icount;
 
 uintptr_t qemu_host_page_size;
 intptr_t qemu_host_page_mask;
-uintptr_t qemu_real_host_page_size;
-intptr_t qemu_real_host_page_mask;
 
 bool set_preferred_target_page_bits(int bits)
 {
@@ -3606,8 +3604,6 @@ void page_size_init(void)
 {
     /* NOTE: we can always suppose that qemu_host_page_size >=
        TARGET_PAGE_SIZE */
-    qemu_real_host_page_size = getpagesize();
-    qemu_real_host_page_mask = -(intptr_t)qemu_real_host_page_size;
     if (qemu_host_page_size == 0) {
         qemu_host_page_size = qemu_real_host_page_size;
     }

include/exec/cpu-all.h

@@ -229,8 +229,6 @@ extern int target_page_bits;
 /* Using intptr_t ensures that qemu_*_page_mask is sign-extended even
  * when intptr_t is 32-bit and we are aligning a long long.
  */
-extern uintptr_t qemu_real_host_page_size;
-extern intptr_t qemu_real_host_page_mask;
 extern uintptr_t qemu_host_page_size;
 extern intptr_t qemu_host_page_mask;
 

include/qemu/osdep.h

@@ -505,6 +505,12 @@ char *qemu_get_pid_name(pid_t pid);
  */
 pid_t qemu_fork(Error **errp);
 
+/* Using intptr_t ensures that qemu_*_page_mask is sign-extended even
+ * when intptr_t is 32-bit and we are aligning a long long.
+ */
+extern uintptr_t qemu_real_host_page_size;
+extern intptr_t qemu_real_host_page_mask;
+
 extern int qemu_icache_linesize;
 extern int qemu_dcache_linesize;
 

util/Makefile.objs

@@ -40,6 +40,7 @@ util-obj-y += buffer.o
 util-obj-y += timed-average.o
 util-obj-y += base64.o
 util-obj-y += log.o
+util-obj-y += pagesize.o
 util-obj-y += qdist.o
 util-obj-y += qht.o
 util-obj-y += range.o

util/pagesize.c

@@ -0,0 +1,18 @@
+/*
+ * pagesize.c - query the host about its page size
+ *
+ * Copyright (C) 2017, Emilio G. Cota <cota@braap.org>
+ * License: GNU GPL, version 2 or later.
+ *   See the COPYING file in the top-level directory.
+ */
+
+#include "qemu/osdep.h"
+
+uintptr_t qemu_real_host_page_size;
+intptr_t qemu_real_host_page_mask;
+
+static void __attribute__((constructor)) init_real_host_page_size(void)
+{
+    qemu_real_host_page_size = getpagesize();
+    qemu_real_host_page_mask = -(intptr_t)qemu_real_host_page_size;
+}