interpreters/python: add patch to set _PyRuntime section

By setting a specific region for the `_PyRuntime` structure, it is
possible to move it to the external memory, for instance, freeing
the internal memory (this structure occupies around 140KiB).

Author: tmedicci

interpreters/python/Makefile

@@ -80,6 +80,7 @@ $(CPYTHON_UNPACKNAME): $(CPYTHON_ZIP)
 	$(Q) patch -p1 -d $(CPYTHON_UNPACKNAME) < patch$(DELIM)0009-include-nuttx-sys-select-header-to-define-FD_SETSIZE.patch
 	$(Q) patch -p1 -d $(CPYTHON_UNPACKNAME) < patch$(DELIM)0010-check-for-the-d_ino-member-of-the-structure-dirent.patch
 	$(Q) patch -p1 -d $(CPYTHON_UNPACKNAME) < patch$(DELIM)0011-avoid-redefinition-warning-if-UNUSED-is-already-defi.patch
+	$(Q) patch -p1 -d $(CPYTHON_UNPACKNAME) < patch$(DELIM)0012-hack-place-_PyRuntime-structure-into-PSRAM-bss-regio.patch
 
 $(HOSTPYTHON):
 	mkdir -p $(HOSTBUILD)

interpreters/python/patch/0012-hack-place-_PyRuntime-structure-into-PSRAM-bss-regio.patch

@@ -0,0 +1,54 @@
+From d1e903f516849c535455904b3c3f8a33665c1a88 Mon Sep 17 00:00:00 2001
+From: Ivan Grokhotkov <[email protected]>
+Date: Wed, 23 Oct 2024 16:52:52 +0200
+Subject: [PATCH 12/12] hack: place _PyRuntime structure into PSRAM bss region,
+ initialize later
+
+_PyRuntime occupies around 100kB of RAM in .data region, making it
+hard to fit the interpreter into the available static RAM.
+This patch moves it into PSRAM using section attribute. Normally
+we shouldn't need this as we can specify placements in ldfragments,
+however in this specific case I couldn't get it to work.
+Since the structure is now in .bss, add a function which will assign
+it the initial value.
+
+The proper fix might be to support .data segment on PSRAM in IDF,
+as well as to fix whatever ldgen issue prevents this variable from
+being moved to PSRAM.
+
+Co-authored-by: Tiago Medicci Serrano <[email protected]>
+---
+ Python/pylifecycle.c | 11 +++++++++++
+ 1 file changed, 11 insertions(+)
+
+diff --git a/Python/pylifecycle.c b/Python/pylifecycle.c
+index 1701a1cd217..2a8e544f0ac 100644
+--- a/Python/pylifecycle.c
++++ b/Python/pylifecycle.c
+@@ -102,12 +102,23 @@ __attribute__((
+ _PyRuntimeState _PyRuntime
+ #if defined(__linux__) && (defined(__GNUC__) || defined(__clang__))
+ __attribute__ ((section (".PyRuntime")))
++#elif defined(ESP_PLATFORM)
++__attribute__ ((section (".PyRuntime")))
+ #endif
+ = _PyRuntimeState_INIT(_PyRuntime, _Py_Debug_Cookie);
+ _Py_COMP_DIAG_POP
+ 
+ static int runtime_initialized = 0;
+ 
++void _PyRuntime_Early_Init(void) {
++#if defined(ESP_PLATFORM)
++    // Normally, _PyRuntime is in .data and is initialized by the C runtime.
++    // This function allows us to place it into external RAM .bss section
++    // and initialize it manually, saving some internal RAM.
++    _PyRuntime = (struct pyruntimestate) _PyRuntimeState_INIT(_PyRuntime, _Py_Debug_Cookie);
++#endif
++}
++
+ PyStatus
+ _PyRuntime_Initialize(void)
+ {
+-- 
+2.47.1
+