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-rw-r--r--page-vary.c79
1 files changed, 6 insertions, 73 deletions
diff --git a/page-vary.c b/page-vary.c
index 344f9fcf76..057c7f1815 100644
--- a/page-vary.c
+++ b/page-vary.c
@@ -17,92 +17,25 @@
* License along with this library; if not, see <http://www.gnu.org/licenses/>.
*/
+#define IN_PAGE_VARY 1
+
#include "qemu/osdep.h"
#include "qemu-common.h"
-
-#define IN_EXEC_VARY 1
-
#include "exec/exec-all.h"
-#ifdef TARGET_PAGE_BITS_VARY
-# ifdef CONFIG_ATTRIBUTE_ALIAS
-/*
- * We want to declare the "target_page" variable as const, which tells
- * the compiler that it can cache any value that it reads across calls.
- * This avoids multiple assertions and multiple reads within any one user.
- *
- * This works because we finish initializing the data before we ever read
- * from the "target_page" symbol.
- *
- * This also requires that we have a non-constant symbol by which we can
- * perform the actual initialization, and which forces the data to be
- * allocated within writable memory. Thus "init_target_page", and we use
- * that symbol exclusively in the two functions that initialize this value.
- *
- * The "target_page" symbol is created as an alias of "init_target_page".
- */
-static TargetPageBits init_target_page;
-
-/*
- * Note that this is *not* a redundant decl, this is the definition of
- * the "target_page" symbol. The syntax for this definition requires
- * the use of the extern keyword. This seems to be a GCC bug in
- * either the syntax for the alias attribute or in -Wredundant-decls.
- *
- * See https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91765
- */
-# pragma GCC diagnostic push
-# pragma GCC diagnostic ignored "-Wredundant-decls"
-
-extern const TargetPageBits target_page
- __attribute__((alias("init_target_page")));
-
-# pragma GCC diagnostic pop
-# else
-/*
- * When aliases are not supported then we force two different declarations,
- * by way of suppressing the header declaration with IN_EXEC_VARY.
- * We assume that on such an old compiler, LTO cannot be used, and so the
- * compiler cannot not detect the mismatched declarations, and all is well.
- */
-TargetPageBits target_page;
-# define init_target_page target_page
-# endif
-#endif
-
bool set_preferred_target_page_bits(int bits)
{
- /*
- * The target page size is the lowest common denominator for all
- * the CPUs in the system, so we can only make it smaller, never
- * larger. And we can't make it smaller once we've committed to
- * a particular size.
- */
#ifdef TARGET_PAGE_BITS_VARY
assert(bits >= TARGET_PAGE_BITS_MIN);
- if (init_target_page.bits == 0 || init_target_page.bits > bits) {
- if (init_target_page.decided) {
- return false;
- }
- init_target_page.bits = bits;
- }
-#endif
+ return set_preferred_target_page_bits_common(bits);
+#else
return true;
+#endif
}
void finalize_target_page_bits(void)
{
#ifdef TARGET_PAGE_BITS_VARY
- if (init_target_page.bits == 0) {
- init_target_page.bits = TARGET_PAGE_BITS_MIN;
- }
- init_target_page.mask = (target_long)-1 << init_target_page.bits;
- init_target_page.decided = true;
-
- /*
- * For the benefit of an -flto build, prevent the compiler from
- * hoisting a read from target_page before we finish initializing.
- */
- barrier();
+ finalize_target_page_bits_common(TARGET_PAGE_BITS_MIN);
#endif
}