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.


git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@5844 c046a42c-6fe2-441c-8c8c-71466251a162

1 files changed, 6 insertions, 0 deletions

diff --git a/exec.c b/exec.c
index 3523c9577e..1aa64327af 100644
--- a/exec.c
+++ b/exec.c
@@ -436,6 +436,12 @@ static void code_gen_alloc(unsigned long tb_size)
         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,