From ba41c0911dc70b1794e00e3974dd092cd4fe2afb Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Mario=20H=C3=BCttel?= <mario.huettel@gmx.net>
Date: Mon, 7 Sep 2020 21:03:37 +0200
Subject: [PATCH] Add necessary sections for stack protection area and
 implement fill function

---
 .../include/reflow-controller/stack-check.h   |  4 ++
 stm-firmware/stack-check.c                    | 43 ++++++++++++++++++-
 stm-firmware/stm32f407vet6_flash.ld           |  7 +++
 3 files changed, 52 insertions(+), 2 deletions(-)

diff --git a/stm-firmware/include/reflow-controller/stack-check.h b/stm-firmware/include/reflow-controller/stack-check.h
index 8e0e290..c51a3a7 100644
--- a/stm-firmware/include/reflow-controller/stack-check.h
+++ b/stm-firmware/include/reflow-controller/stack-check.h
@@ -50,4 +50,8 @@ static inline uint32_t read_stack_pointer()
 	return stack_pointer;
 }
 
+int stack_check_init_corruption_detect_area(void);
+
+int stack_check_corruption_detect_area(void);
+
 #endif /* __STACK_CHECK_H__ */
diff --git a/stm-firmware/stack-check.c b/stm-firmware/stack-check.c
index 666014d..41e55e7 100644
--- a/stm-firmware/stack-check.c
+++ b/stm-firmware/stack-check.c
@@ -20,9 +20,10 @@
 
 #include <reflow-controller/stack-check.h>
 #include <stdint.h>
+#include <stm-periph/rng.h>
 
 extern char __ld_top_of_stack;
-extern char __ld_eheap;
+extern char __ld_end_stack;
 
 int32_t stack_check_get_usage()
 {
@@ -41,7 +42,45 @@ int32_t stack_check_get_free()
 	uint32_t stack_ptr;
 
 	stack_ptr = read_stack_pointer();
-	upper_heap_boundary = (uint32_t)&__ld_eheap;
+	upper_heap_boundary = (uint32_t)&__ld_end_stack;
 
 	return stack_ptr - upper_heap_boundary;
 }
+
+extern uint32_t __ld_start_stack_corruption_detect_area;
+extern uint32_t __ld_end_stack_corruption_detect_area;
+
+int stack_check_init_corruption_detect_area(void)
+{
+	volatile uint32_t *ptr = &__ld_start_stack_corruption_detect_area;
+	volatile uint32_t *end_ptr = &__ld_end_stack_corruption_detect_area;
+	enum random_number_error rng_stat;
+	uint32_t rng_number;
+	int ret = 0;
+
+	end_ptr--;
+
+	random_number_gen_init(false);
+
+	while (ptr < end_ptr) {
+		rng_stat = random_number_gen_get_number(&rng_number, true);
+
+		if (rng_stat != RNG_ERROR_OK) {
+			ret = -1;
+			goto exit_deinit_rng;
+		}
+
+		*ptr = rng_number;
+		ptr++;
+	}
+
+exit_deinit_rng:
+	random_number_gen_deinit();
+
+	return ret;
+}
+
+int stack_check_corruption_detect_area(void)
+{
+
+}
diff --git a/stm-firmware/stm32f407vet6_flash.ld b/stm-firmware/stm32f407vet6_flash.ld
index e1f503a..bbb2809 100644
--- a/stm-firmware/stm32f407vet6_flash.ld
+++ b/stm-firmware/stm32f407vet6_flash.ld
@@ -25,6 +25,7 @@
 /* USER PARAMETERS */
 __ld_stack_size = 0x3000;
 __ld_heap_size  = 0x2100;
+__stack_corruption_area_size = 64;
 
 /* END OF USER PARAMETERS */
 ENTRY(Reset_Handler)
@@ -150,6 +151,12 @@ SECTIONS
 		__ld_sheap = .;
 		. = . + __ld_heap_size;
 		__ld_eheap = .;
+		. = ALIGN(4)
+		__ld_start_stack_corruption_detect_area = .;
+		. = . + __stack_corruption_area_size;
+		. = ALIGN(4);
+		__ld_end_stack_corruption_detect_area = .;
+		__ld_end_stack = .
 		. = . + __ld_stack_size;
 		. = ALIGN(4);
 	} >RAM