Core locking and MPU

Overview

Macros
#define	LWIP_MPU_COMPATIBLE   0
#define	LWIP_TCPIP_CORE_LOCKING   1
#define	LWIP_TCPIP_CORE_LOCKING_INPUT   0
#define	SYS_LIGHTWEIGHT_PROT   1
#define	LWIP_ASSERT_CORE_LOCKED()
#define	LWIP_MARK_TCPIP_THREAD()

Macro Definition Documentation

#define LWIP_MPU_COMPATIBLE   0

LWIP_MPU_COMPATIBLE: enables special memory management mechanism which makes lwip able to work on MPU (Memory Protection Unit) system by not passing stack-pointers to other threads (this decreases performance as memory is allocated from pools instead of keeping it on the stack)

#define LWIP_TCPIP_CORE_LOCKING   1

LWIP_TCPIP_CORE_LOCKING Creates a global mutex that is held during TCPIP thread operations. Can be locked by client code to perform lwIP operations without changing into TCPIP thread using callbacks. See LOCK_TCPIP_CORE() and UNLOCK_TCPIP_CORE(). Your system should provide mutexes supporting priority inversion to use this.

#define LWIP_TCPIP_CORE_LOCKING_INPUT   0

LWIP_TCPIP_CORE_LOCKING_INPUT: when LWIP_TCPIP_CORE_LOCKING is enabled, this lets tcpip_input() grab the mutex for input packets as well, instead of allocating a message and passing it to tcpip_thread.

ATTENTION: this does not work when tcpip_input() is called from interrupt context!

#define SYS_LIGHTWEIGHT_PROT   1

SYS_LIGHTWEIGHT_PROT==1: enable inter-task protection (and task-vs-interrupt protection) for certain critical regions during buffer allocation, deallocation and memory allocation and deallocation. ATTENTION: This is required when using lwIP from more than one context! If you disable this, you must be sure what you are doing!

#define LWIP_ASSERT_CORE_LOCKED

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Macro/function to check whether lwIP's threading/locking requirements are satisfied during current function call. This macro usually calls a function that is implemented in the OS-dependent sys layer and performs the following checks:

• Not in ISR (this should be checked for NO_SYS==1, too!)
• If LWIP_TCPIP_CORE_LOCKING = 1: TCPIP core lock is held
• If LWIP_TCPIP_CORE_LOCKING = 0: function is called from TCPIP thread

  See Also

  Multithreading

#define LWIP_MARK_TCPIP_THREAD

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Called as first thing in the lwIP TCPIP thread. Can be used in conjunction with LWIP_ASSERT_CORE_LOCKED to check core locking.

See Also

Multithreading