Fix kalloc. Now the HEAP START and HEAP END globals are defined by the linker script.

2 files changed, 13 insertions, 8 deletions

diff --git a/src/kern/main.c b/src/kern/main.c
index 1eedb59..a6743d5 100644
--- a/src/kern/main.c
+++ b/src/kern/main.c
@@ -2,6 +2,8 @@
 #include "arch/stm32l4xxx/peripherals/clock.h"
 #include "arch/stm32l4xxx/peripherals/system.h"
 #include "kern/log.h"
+#include "kern/panic.h"
+#include "kern/init.h"
 
 void on_systick() /* Overrides weak-symbol on_systick. */
 {
@@ -14,6 +16,8 @@ void on_systick() /* Overrides weak-symbol on_systick. */
 int main()
 {
   klogf("Hello, World! Clock Mhz: %d\n", (uint32_t)get_clock_mhz());
+  klogf("Heap Start: %p\n", &HEAP_START);
+  klogf("Heap End  : %p\n", &HEAP_STOP);
 
   /* Set the countdown to start from 10,000,0000. */
   SCB.strv_r = 10000000;
diff --git a/src/kern/mem.c b/src/kern/mem.c
index eb4527e..533b394 100644
--- a/src/kern/mem.c
+++ b/src/kern/mem.c
@@ -1,7 +1,6 @@
 #include "kern/mem.h"
 
 #include "arch.h"
-
 #include "kern/common.h"
 #include "kern/panic.h"
 
@@ -55,8 +54,11 @@ static_assert(offsetof(kalloc_node_t, mem) == 4, "Offset check failed.");
 
 kalloc_node_t* kalloc_start;
 
-#define kalloc_node_out_of_range(node) \
-  ((uint8_t*)(node) == ((uint8_t*)&DATA_SEGMENT_STOP) + MAX_HEAP_SIZE)
+#define HEAP_START_ADDR ((ptrdiff_t)&HEAP_START)
+#define REAL_HEAP_START \
+  (*((unsigned char*)((HEAP_START_ADDR & (~3)) + (HEAP_START_ADDR % 4 != 0))))
+#define MAX_HEAP_SIZE ((&HEAP_STOP - &REAL_HEAP_START))
+#define kalloc_node_out_of_range(node) ((void*)(node) >= (void*)&HEAP_STOP)
 
 #define kalloc_node_next(cur) \
   ((kalloc_node_t*)(((uint8_t*)(cur)) + (((cur)->size + 1) * 4)))
@@ -76,7 +78,7 @@ kalloc_node_t* kalloc_start;
 void* kalloc(size_t size)
 {
   if (!kalloc_start) {
-    kalloc_start = (kalloc_node_t*)DATA_SEGMENT_STOP_ADDR;
+    kalloc_start = (kalloc_node_t*)&REAL_HEAP_START;
     memset(kalloc_start, 0, sizeof(kalloc_node_t));
     kalloc_start->size = (MAX_HEAP_SIZE / 4) - 1;
     kalloc_start->canary = CANARY;
@@ -224,16 +226,15 @@ int debug_kalloc_assert_consistency(char* error, size_t len)
     total_size += cur->size + 1;
 
     kalloc_node_t* next = kalloc_node_next(cur);
-    if ((uint8_t*)next == ((uint8_t*)&DATA_SEGMENT_STOP) + MAX_HEAP_SIZE) {
+    if ((void*)next == (void*)&HEAP_STOP) {
       break;
-    } else if (
-        (uint8_t*)next > (uint8_t*)DATA_SEGMENT_STOP_ADDR + MAX_HEAP_SIZE) {
+    } else if ((void*)next > (void*)&HEAP_STOP) {
       snprintf(
           error,
           len,
           "Next node points is out of bounds. %p vs max of %p\n",
           next,
-          (void*)(DATA_SEGMENT_STOP_ADDR + MAX_HEAP_SIZE));
+          &HEAP_STOP);
       return 1;
     }