From 22b5de86a521b87131ddfd27eca67723836e7be2 Mon Sep 17 00:00:00 2001
From: Ian Martin <ian@locicontrols.com>
Date: Mon, 24 Oct 2016 12:40:44 -0400
Subject: [PATCH] add mpu_stack_guard pseudomodule (just Cortex-M for now)
triggers an exception during stack overflow,
but at a cost of 32-63 bytes of RAM per thread.
---
Makefile.pseudomodules | 1 +
cpu/cortexm_common/vectors_cortexm.c | 19 +++++++++++++++++++
2 files changed, 20 insertions(+)
diff --git a/Makefile.pseudomodules b/Makefile.pseudomodules
index e90712cf7d..9e02789345 100644
--- a/Makefile.pseudomodules
+++ b/Makefile.pseudomodules
@@ -34,6 +34,7 @@ PSEUDOMODULES += lwip_stats
PSEUDOMODULES += lwip_tcp
PSEUDOMODULES += lwip_udp
PSEUDOMODULES += lwip_udplite
+PSEUDOMODULES += mpu_stack_guard
PSEUDOMODULES += netdev_default
PSEUDOMODULES += netif
PSEUDOMODULES += netstats
diff --git a/cpu/cortexm_common/vectors_cortexm.c b/cpu/cortexm_common/vectors_cortexm.c
index a5b5c38129..74e584cd27 100644
--- a/cpu/cortexm_common/vectors_cortexm.c
+++ b/cpu/cortexm_common/vectors_cortexm.c
@@ -28,9 +28,14 @@
#include "cpu.h"
#include "kernel_init.h"
#include "board.h"
+#include "mpu.h"
#include "panic.h"
#include "vectors_cortexm.h"
+#ifndef SRAM_BASE
+#define SRAM_BASE 0
+#endif
+
/**
* @brief Memory markers, defined in the linker script
* @{
@@ -48,6 +53,8 @@ extern uint32_t _sram;
extern uint32_t _eram;
/** @} */
+static const uintptr_t stack_base = (uintptr_t)&_sstack;
+
/**
* @brief Allocation of the interrupt stack
*/
@@ -94,6 +101,18 @@ void reset_handler_default(void)
*(dst++) = 0;
}
+#ifdef MODULE_MPU_STACK_GUARD
+ if (stack_base != SRAM_BASE) {
+ mpu_configure(
+ 0, /* MPU region 0 */
+ stack_base + 31, /* Base Address (rounded up) */
+ MPU_ATTR(1, AP_RO_RO, 0, 1, 0, 1, MPU_SIZE_32B) /* Attributes and Size */
+ );
+
+ mpu_enable();
+ }
+#endif
+
post_startup();
/* initialize the board (which also initiates CPU initialization) */
--
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