Automatic stack location selection (SYS or HEAP), remove unnecessary board generator option

Author: d-a-v

cores/esp8266/cont.h

@@ -45,6 +45,12 @@ typedef struct cont_ {
         unsigned* struct_start;
 } cont_t;
 
+/* Not static, used in core_esp8266_postmortem.c.
+ * Placed into noinit section because we assign value to this variable
+ * before .bss is zero-filled, and need to preserve the value.
+ */
+extern cont_t* g_pcont __attribute__((section(".noinit")));
+
 // Initialize the cont_t structure before calling cont_run
 void cont_init(cont_t*);
 

cores/esp8266/core_esp8266_app_entry_noextra4k.cpp

@@ -0,0 +1,38 @@
+/*
+ *  This is the original app_entry() not providing extra 4K heap, but allowing
+ *  the use of WPS.
+ *
+ *  see comments in core_esp8266_main.cpp's app_entry()
+ *
+ */
+
+#include <c_types.h>
+#include "cont.h"
+#include "coredecls.h"
+
+// calls to this function must *always* be inlined
+void disable_extra4k_at_link_time (void)
+{
+    /*
+     * does nothing
+     * allows overriding the core_esp8266_main.cpp's app_entry()
+     * by this one below, at link time
+     *
+     */
+}
+
+/* the following code is linked only if a call to the above function is made somewhere */
+
+extern "C" void call_user_start();
+
+/* this is the default NONOS-SDK user's heap location */
+static cont_t g_cont __attribute__ ((aligned (16)));
+
+extern "C" void ICACHE_RAM_ATTR app_entry_redefinable(void)
+{
+    /* this is the default NONOS-SDK user's heap location */
+    g_pcont = &g_cont;
+
+    /* Call the entry point of the SDK code. */
+    call_user_start();
+}

cores/esp8266/core_esp8266_main.cpp

@@ -175,10 +175,15 @@ void init_done() {
 
    WPS beeing flawed by its poor security, or not beeing used by lots of
    users, it has been decided that we are still going to use that memory for
-   user's stack and disable the use of WPS, with an option to revert that
-   back at the user's discretion.  This selection can be done with the
-   global define NO_EXTRA_4K_HEAP.  An option has been added to the board
-   generator script.
+   user's stack and disable the use of WPS.
+
+   app_entry() jumps to app_entry_custom() defined as "weakref" calling
+   itself a weak customizable function, allowing to use another one when
+   this is required (see core_esp8266_app_entry_noextra4k.cpp, used by WPS).
+
+   (note: setting app_entry() itself as "weak" is not sufficient and always
+    ends up with the other "noextra4k" one linked, maybe because it has a
+    default value in linker scripts).
 
    References:
    https://github.com/esp8266/Arduino/pull/4553
@@ -188,31 +193,25 @@ void init_done() {
 
 */
 
-#ifdef NO_EXTRA_4K_HEAP
-/* this is the default NONOS-SDK user's heap location */
-cont_t g_cont __attribute__ ((aligned (16)));
-#endif
-
-extern "C" void ICACHE_RAM_ATTR app_entry(void)
+extern "C" void ICACHE_RAM_ATTR app_entry_redefinable(void) __attribute__((weak));
+extern "C" void ICACHE_RAM_ATTR app_entry_redefinable(void)
 {
-#ifdef NO_EXTRA_4K_HEAP
-
-    /* this is the default NONOS-SDK user's heap location */
-    g_pcont = &g_cont;
-
-#else
-
     /* Allocate continuation context on this SYS stack,
        and save pointer to it. */
     cont_t s_cont __attribute__((aligned(16)));
     g_pcont = &s_cont;
 
-#endif
-
     /* Call the entry point of the SDK code. */
     call_user_start();
 }
 
+static void ICACHE_RAM_ATTR app_entry_custom (void) __attribute__((weakref("app_entry_redefinable")));
+
+extern "C" void ICACHE_RAM_ATTR app_entry (void)
+{
+    return app_entry_custom();
+}
+
 extern "C" void user_init(void) {
     struct rst_info *rtc_info_ptr = system_get_rst_info();
     memcpy((void *) &resetInfo, (void *) rtc_info_ptr, sizeof(resetInfo));

cores/esp8266/coredecls.h

@@ -8,11 +8,17 @@ extern "C" {
 
 // TODO: put declarations here, get rid of -Wno-implicit-function-declaration
 
+
 extern bool timeshift64_is_set;
 
+void esp_yield();
+void esp_schedule();
 void tune_timeshift64 (uint64_t now_us);
 void settimeofday_cb (void (*cb)(void));
 
+// calls to this function must *always* be inlined
+void disable_extra4k_at_link_time (void) __attribute__((noinline));
+
 #ifdef __cplusplus
 }
 #endif

libraries/ESP8266WiFi/src/ESP8266WiFiSTA-WPS.cpp

@@ -0,0 +1,84 @@
+
+#include "ESP8266WiFi.h"
+#include "ESP8266WiFiGeneric.h"
+#include "ESP8266WiFiSTA.h"
+
+void wifi_wps_status_cb(wps_cb_status status);
+
+/**
+ * WPS config
+ * so far only WPS_TYPE_PBC is supported (SDK 1.2.0)
+ * @return ok
+ */
+bool beginWPSConfig(void) {
+
+    if(!WiFi.enableSTA(true)) {
+        // enable STA failed
+        return false;
+    }
+
+    WiFi.disconnect();
+
+    DEBUGV("wps begin\n");
+
+    if(!wifi_wps_disable()) {
+        DEBUGV("wps disable failed\n");
+        return false;
+    }
+
+    // so far only WPS_TYPE_PBC is supported (SDK 1.2.0)
+    if(!wifi_wps_enable(WPS_TYPE_PBC)) {
+        DEBUGV("wps enable failed\n");
+        return false;
+    }
+
+    if(!wifi_set_wps_cb((wps_st_cb_t) &wifi_wps_status_cb)) {
+        DEBUGV("wps cb failed\n");
+        return false;
+    }
+
+    if(!wifi_wps_start()) {
+        DEBUGV("wps start failed\n");
+        return false;
+    }
+
+    esp_yield();
+    // will return here when wifi_wps_status_cb fires
+
+    return true;
+}
+
+/**
+ * WPS callback
+ * @param status wps_cb_status
+ */
+void wifi_wps_status_cb(wps_cb_status status) {
+    DEBUGV("wps cb status: %d\r\n", status);
+    switch(status) {
+        case WPS_CB_ST_SUCCESS:
+            if(!wifi_wps_disable()) {
+                DEBUGV("wps disable failed\n");
+            }
+            wifi_station_connect();
+            break;
+        case WPS_CB_ST_FAILED:
+            DEBUGV("wps FAILED\n");
+            break;
+        case WPS_CB_ST_TIMEOUT:
+            DEBUGV("wps TIMEOUT\n");
+            break;
+        case WPS_CB_ST_WEP:
+            DEBUGV("wps WEP\n");
+            break;
+        case WPS_CB_ST_UNK:
+            DEBUGV("wps UNKNOWN\n");
+            if(!wifi_wps_disable()) {
+                DEBUGV("wps disable failed\n");
+            }
+            break;
+    }
+    // TODO user function to get status
+
+    esp_schedule(); // resume the beginWPSConfig function
+}
+

libraries/ESP8266WiFi/src/ESP8266WiFiSTA.cpp

@@ -571,90 +571,6 @@ int32_t ESP8266WiFiSTAClass::RSSI(void) {
 // -------------------------------------------------- STA remote configure -----------------------------------------------
 // -----------------------------------------------------------------------------------------------------------------------
 
-#ifdef NO_EXTRA_4K_HEAP
-/* NO_EXTRA_4K_HEAP's description in cores/esp8266/core_esp8266_main.cpp */
-
-void wifi_wps_status_cb(wps_cb_status status);
-
-/**
- * WPS config
- * so far only WPS_TYPE_PBC is supported (SDK 1.2.0)
- * @return ok
- */
-bool ESP8266WiFiSTAClass::beginWPSConfig(void) {
-
-    if(!WiFi.enableSTA(true)) {
-        // enable STA failed
-        return false;
-    }
-
-    disconnect();
-
-    DEBUGV("wps begin\n");
-
-    if(!wifi_wps_disable()) {
-        DEBUGV("wps disable failed\n");
-        return false;
-    }
-
-    // so far only WPS_TYPE_PBC is supported (SDK 1.2.0)
-    if(!wifi_wps_enable(WPS_TYPE_PBC)) {
-        DEBUGV("wps enable failed\n");
-        return false;
-    }
-
-    if(!wifi_set_wps_cb((wps_st_cb_t) &wifi_wps_status_cb)) {
-        DEBUGV("wps cb failed\n");
-        return false;
-    }
-
-    if(!wifi_wps_start()) {
-        DEBUGV("wps start failed\n");
-        return false;
-    }
-
-    esp_yield();
-    // will return here when wifi_wps_status_cb fires
-
-    return true;
-}
-
-/**
- * WPS callback
- * @param status wps_cb_status
- */
-void wifi_wps_status_cb(wps_cb_status status) {
-    DEBUGV("wps cb status: %d\r\n", status);
-    switch(status) {
-        case WPS_CB_ST_SUCCESS:
-            if(!wifi_wps_disable()) {
-                DEBUGV("wps disable failed\n");
-            }
-            wifi_station_connect();
-            break;
-        case WPS_CB_ST_FAILED:
-            DEBUGV("wps FAILED\n");
-            break;
-        case WPS_CB_ST_TIMEOUT:
-            DEBUGV("wps TIMEOUT\n");
-            break;
-        case WPS_CB_ST_WEP:
-            DEBUGV("wps WEP\n");
-            break;
-        case WPS_CB_ST_UNK:
-            DEBUGV("wps UNKNOWN\n");
-            if(!wifi_wps_disable()) {
-                DEBUGV("wps disable failed\n");
-            }
-            break;
-    }
-    // TODO user function to get status
-
-    esp_schedule(); // resume the beginWPSConfig function
-}
-
-#endif // NO_EXTRA_4K_HEAP
-
 bool ESP8266WiFiSTAClass::_smartConfigStarted = false;
 bool ESP8266WiFiSTAClass::_smartConfigDone = false;
 

libraries/ESP8266WiFi/src/ESP8266WiFiSTA.h

@@ -27,7 +27,9 @@
 #include "ESP8266WiFiType.h"
 #include "ESP8266WiFiGeneric.h"
 #include "user_interface.h"
+#include "coredecls.h" // disable_extra4k_at_link_time()
 
+extern bool beginWPSConfig(void);
 
 class ESP8266WiFiSTAClass {
         // ----------------------------------------------------------------------------------------------
@@ -93,14 +95,12 @@ class ESP8266WiFiSTAClass {
 
     public:
 
-#ifdef NO_EXTRA_4K_HEAP
-        bool beginWPSConfig(void);
-#else
-        inline bool beginWPSConfig(void) __attribute__((always_inline)) {
-            return WPS_is_unavailable_in_this_configuration__Please_check_FAQ_or_board_generator_tool();
+        inline bool beginWPSConfig(void) __attribute__((always_inline))
+        {
+            disable_extra4k_at_link_time(); // this call must always be inlined
+            return ::beginWPSConfig();
         }
-#endif
-
+        
         bool beginSmartConfig();
         bool stopSmartConfig();
         bool smartConfigDone();

libraries/ESP8266WiFi/src/WiFiClientSecureBearSSL.cpp

@@ -1260,13 +1260,13 @@ bool WiFiClientSecure::loadPrivateKey(Stream& stream, size_t size) {
 
 extern "C" {
 #include <cont.h>
-  extern cont_t g_cont;
+  extern cont_t *g_pcont;
   extern size_t br_esp8266_stack_proxy_usage();
 
   void _BearSSLCheckStack(const char *fcn, const char *file, int line) {
     static int cnt = 0;
     register uint32_t *sp asm("a1");
-    int freestack = 4 * (sp - g_cont.stack);
+    int freestack = 4 * (sp - g_pcont->stack);
     int freeheap = ESP.getFreeHeap();
     static int laststack, lastheap, laststack2;
     if ((laststack != freestack) || (lastheap != freeheap) || (laststack2 != (int)br_esp8266_stack_proxy_usage())) {

libraries/esp8266/examples/extra4kchecker/extra4kchecker.ino

@@ -0,0 +1,42 @@
+
+/*
+   This is a debugging / validation test only
+
+   It demonstrates the effect of calling
+       disable_extra4k_at_link_time()
+
+   Currently only WPS is using that call
+
+   released to public domain
+*/
+
+#include <ESP8266WiFi.h>
+#include <cont.h>
+
+#define USE_WPS 0 // try me with 0 or 1
+
+extern cont_t* g_pcont;
+
+void setup() {
+
+  Serial.begin(115200);
+  Serial.setDebugOutput(true);
+  WiFi.mode(WIFI_STA);
+  bool sysstack = (((unsigned long)g_pcont) >> 16) == 0x3fff;
+  Serial.printf("\nUsing sys stack: %s\ncont: %p (USER:0x3ffe SYS:0x3fff)\n"
+                "check https://github.com/esp8266/esp8266-wiki/wiki/Memory-Map)\n",
+                sysstack ? "YES" : "NO",
+                g_pcont);
+
+  Serial.printf("FreeHeap: %d (~52112 without WPS, ~46832 with)\n", ESP.getFreeHeap());
+
+#if USE_WPS
+  Serial.printf("starting WPS...\n");
+  Serial.printf("wps: %d\n", WiFi.beginWPSConfig());
+#else
+  Serial.printf("done\n");
+#endif
+}
+
+void loop() {
+}