unix/alloc: Add option to use uPy's alloc-exec implementation even for libffi.

When built for Linux, libffi includes very bloated and workaround exec-alloc
implementation required to work around SELinux and other "sekuritee" features
which real people don't use. MicroPython has own alloc-exec implementation,
used to alloc memory for @micropython.native code. With this option enabled,
uPy's implementation will override libffi's. This saves 11K on x86_64 (and
that accounts for more than half of the libffi code size).

TODO: Possibly, we want to refactor this option to allow either use uPy's
implementation even for libffi, or allow to use libffi's implementation even
for uPy.

1 files changed, 5 insertions, 0 deletions

diff --git a/unix/mpconfigport.h b/unix/mpconfigport.h
index c824a46fd..20ad2e26d 100644
--- a/unix/mpconfigport.h
+++ b/unix/mpconfigport.h
@@ -234,6 +234,11 @@ void mp_unix_free_exec(void *ptr, mp_uint_t size);
 void mp_unix_mark_exec(void);
 #define MP_PLAT_ALLOC_EXEC(min_size, ptr, size) mp_unix_alloc_exec(min_size, ptr, size)
 #define MP_PLAT_FREE_EXEC(ptr, size) mp_unix_free_exec(ptr, size)
+#ifndef MICROPY_FORCE_PLAT_ALLOC_EXEC
+// Use MP_PLAT_ALLOC_EXEC for any executable memory allocation, including for FFI
+// (overriding libffi own implementation)
+#define MICROPY_FORCE_PLAT_ALLOC_EXEC (1)
+#endif
 
 #if MICROPY_PY_OS_DUPTERM
 #define MP_PLAT_PRINT_STRN(str, len) mp_hal_stdout_tx_strn_cooked(str, len)