tcg-s390: Allocate the code_gen_buffer near the main program.
This allows the use of direct calls to the helpers,
and a direct branch back to the epilogue.
Signed-off-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
diff --git a/exec.c b/exec.c
index aedfda4..4273797 100644
--- a/exec.c
+++ b/exec.c
@@ -519,6 +519,13 @@
start = (void *) 0x01000000UL;
if (code_gen_buffer_size > 16 * 1024 * 1024)
code_gen_buffer_size = 16 * 1024 * 1024;
+#elif defined(__s390x__)
+ /* Map the buffer so that we can use direct calls and branches. */
+ /* We have a +- 4GB range on the branches; leave some slop. */
+ if (code_gen_buffer_size > (3ul * 1024 * 1024 * 1024)) {
+ code_gen_buffer_size = 3ul * 1024 * 1024 * 1024;
+ }
+ start = (void *)0x90000000UL;
#endif
code_gen_buffer = mmap(start, code_gen_buffer_size,
PROT_WRITE | PROT_READ | PROT_EXEC,
