[Qemu-devel] [5844] arm: Reserve code buffer in memory range reachable for pc-relative branch.

[Andrzej Zaborowski]

Revision: 5844
          http://svn.sv.gnu.org/viewvc/?view=rev&root=qemu&revision=5844
Author:   balrog
Date:     2008-12-01 02:10:17 +0000 (Mon, 01 Dec 2008)

Log Message:
-----------
arm: Reserve code buffer in memory range reachable for pc-relative branch.

Unfortunately this range is so narrow that I'm not sure if it makes more
sense to always use memory load to pc kind of branch instead.

Modified Paths:
--------------
    trunk/exec.c

Modified: trunk/exec.c
===================================================================
--- trunk/exec.c        2008-12-01 02:02:37 UTC (rev 5843)
+++ trunk/exec.c        2008-12-01 02:10:17 UTC (rev 5844)
@@ -436,6 +436,12 @@
         start = (void *) 0x60000000UL;
         if (code_gen_buffer_size > (512 * 1024 * 1024))
             code_gen_buffer_size = (512 * 1024 * 1024);
+#elif defined(__arm__)
+        /* Map the buffer below 64M, so we can use direct calls and branches */
+        flags |= MAP_FIXED;
+        start = (void *) 0x01000000UL;
+        if (code_gen_buffer_size > 16 * 1024 * 1024)
+            code_gen_buffer_size = 16 * 1024 * 1024;
 #endif
         code_gen_buffer = mmap(start, code_gen_buffer_size,
                                PROT_WRITE | PROT_READ | PROT_EXEC,