From 5e2ae7ac19220c75d23c2c2f8433d0296d41ddad Mon Sep 17 00:00:00 2001
From: Liu Zhi Fu <liuzhifu@espressif.com>
Date: Thu, 15 Dec 2016 14:37:21 +0800
Subject: [PATCH 1/2] lwip: fix lwip dual core issue
Call xSemaphoreGiveFromISR instead xSemaphoreGive when the calling context is in critical section.
---
components/lwip/port/freertos/sys_arch.c | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)
diff --git a/components/lwip/port/freertos/sys_arch.c b/components/lwip/port/freertos/sys_arch.c
index 8d0dd08c58..9efb151e8e 100755
--- a/components/lwip/port/freertos/sys_arch.c
+++ b/components/lwip/port/freertos/sys_arch.c
@@ -42,6 +42,8 @@
/* This is the number of threads that can be started with sys_thread_new() */
#define SYS_THREAD_MAX 4
+static bool g_lwip_in_critical_section = false;
+
#if !LWIP_COMPAT_MUTEX
/** Create a new mutex
* @param mutex pointer to the mutex to create
@@ -122,7 +124,11 @@ sys_sem_new(sys_sem_t *sem, u8_t count)
void
sys_sem_signal(sys_sem_t *sem)
{
- xSemaphoreGive(*sem);
+ if (g_lwip_in_critical_section){
+ xSemaphoreGiveFromISR(*sem, NULL);
+ } else {
+ xSemaphoreGive(*sem);
+ }
}
/*-----------------------------------------------------------------------------------*/
@@ -453,6 +459,7 @@ sys_prot_t
sys_arch_protect(void)
{
portENTER_CRITICAL(&g_lwip_mux);
+ g_lwip_in_critical_section = true;
return (sys_prot_t) 1;
}
@@ -467,6 +474,7 @@ void
sys_arch_unprotect(sys_prot_t pval)
{
(void) pval;
+ g_lwip_in_critical_section = false;
portEXIT_CRITICAL(&g_lwip_mux);
}
From 55726385a44a565b707707a91d12adacc7cbcd61 Mon Sep 17 00:00:00 2001
From: Liu Zhi Fu <liuzhifu@espressif.com>
Date: Thu, 15 Dec 2016 15:06:00 +0800
Subject: [PATCH 2/2] add more comments and call portYIELD when necessary
---
components/lwip/port/freertos/sys_arch.c | 14 +++++++++++++-
1 file changed, 13 insertions(+), 1 deletion(-)
diff --git a/components/lwip/port/freertos/sys_arch.c b/components/lwip/port/freertos/sys_arch.c
index 9efb151e8e..97ee32d1bd 100755
--- a/components/lwip/port/freertos/sys_arch.c
+++ b/components/lwip/port/freertos/sys_arch.c
@@ -43,6 +43,7 @@
#define SYS_THREAD_MAX 4
static bool g_lwip_in_critical_section = false;
+static BaseType_t g_lwip_critical_section_needs_taskswitch;
#if !LWIP_COMPAT_MUTEX
/** Create a new mutex
@@ -125,7 +126,14 @@ void
sys_sem_signal(sys_sem_t *sem)
{
if (g_lwip_in_critical_section){
- xSemaphoreGiveFromISR(*sem, NULL);
+ /* In function event_callback in sockets.c, lwip signals a semaphore inside a critical
+ * section. According to the FreeRTOS documentation for FreertosTaskEnterCritical, it's
+ * not allowed to call any FreeRTOS API function within a critical region. Unfortunately,
+ * it's not feasible to rework the affected region in LWIP. As a solution, when in a
+ * critical region, we call xSemaphoreGiveFromISR. This routine is hand-vetted to work
+ * in a critical region and it will not cause a task switch.
+ */
+ xSemaphoreGiveFromISR(*sem, &g_lwip_critical_section_needs_taskswitch);
} else {
xSemaphoreGive(*sem);
}
@@ -476,6 +484,10 @@ sys_arch_unprotect(sys_prot_t pval)
(void) pval;
g_lwip_in_critical_section = false;
portEXIT_CRITICAL(&g_lwip_mux);
+ if (g_lwip_critical_section_needs_taskswitch){
+ g_lwip_critical_section_needs_taskswitch = 0;
+ portYIELD();
+ }
}
/*-----------------------------------------------------------------------------------*/