debug.gdb

@@ -1,3 +1,7 @@
 target remote localhost:1234
 set disassembly-flavor intel
 display/4i $rip
+
+# Trying to debug that flanterm page fault
+
+# b plot_char_unscaled_uncanvas if $rdi == 0 || $rsi == 0 || $rdx == 0 || $r10 == 0

src/config.h

@@ -11,7 +11,7 @@
 #define PEPPEROS_VERSION_MAJOR "0"
 #define PEPPEROS_VERSION_MINOR "0"
 #define PEPPEROS_VERSION_PATCH "58"
-#define PEPPEROS_SPLASH "pepperOS version "PEPPEROS_VERSION_MAJOR"."PEPPEROS_VERSION_MINOR"."PEPPEROS_VERSION_PATCH"\n"
+#define PEPPEROS_SPLASH "\x1b[38;5;196mPepperOS\x1b[0m version "PEPPEROS_VERSION_MAJOR"."PEPPEROS_VERSION_MINOR"."PEPPEROS_VERSION_PATCH"\n"
 
 /* process */
 #define PROCESS_NAME_MAX 64

src/debug/panic.c

@@ -9,7 +9,9 @@ void panic(struct cpu_status_t* ctx, const char* str)
 	if (ctx == NULL)
 	{
 		DEBUG("\x1b[38;5;231m\x1b[48;5;196mKernel panic!!!\x1b[0m Something went horribly wrong! (no cpu ctx)");
+		fctprintf((void*)&skputc, 0, "\x1b[38;5;231m\x1b[48;5;27m");
 		DIE_DEBUG(str);
+		fctprintf((void*)&skputc, 0, "\x1b[0m");
 		skputc('\r');
 		skputc('\n');
 		DEBUG("\x1b[38;5;231m\x1b[48;5;196mend Kernel panic - halting...\x1b[0m");

src/io/term/flanterm_backends/fb.c

@@ -25,6 +25,8 @@
  * POSSIBILITY OF SUCH DAMAGE.
  */
 
+#include <kernel.h>
+
 #ifdef __cplusplus
 #error "Please do not compile Flanterm as C++ code! Flanterm should be compiled as C99 or newer."
 #endif
@@ -662,6 +664,17 @@ static void plot_char_unscaled_canvas(struct flanterm_context *_ctx, struct flan
 }
 
 static void plot_char_unscaled_uncanvas(struct flanterm_context *_ctx, struct flanterm_fb_char *c, size_t x, size_t y) {
+    
+    if (_ctx == NULL)
+    {
+        panic(NULL, "plot_char_unscaled_uncanvas: _ctx is NULL");
+    }
+
+    if (c == NULL)
+    {
+        panic(NULL, "plot_char_unscaled_uncanvas: c is NULL");
+    }
+    
     struct flanterm_fb_context *ctx = (void *)_ctx;
 
     if (x >= _ctx->cols || y >= _ctx->rows) {
@@ -953,6 +966,12 @@ static void draw_cursor(struct flanterm_context *_ctx) {
 }
 
 static void flanterm_fb_double_buffer_flush(struct flanterm_context *_ctx) {
+
+    if (_ctx == NULL)
+    {
+        panic(NULL, "flanterm_fb_double_buffer_flush: _ctx is NULL");
+    }
+
     struct flanterm_fb_context *ctx = (void *)_ctx;
 
     if (_ctx->cursor_enabled) {

src/mem/heap/kheap.c

@@ -23,40 +23,36 @@ static uintptr_t end;
 // Kernel root table (level 4)
 extern uint64_t *kernel_pml4;
 
-static void kheap_grow(size_t size)
-{
-    size_t pages = ALIGN_UP(size + sizeof(struct heap_block_t), PAGE_SIZE) / PAGE_SIZE;
-    
-    if (pages == 0) pages = 1;
-    
-    for (size_t i = 0; i < pages; i++)
-    {
-        kheap_map_page();
-    }
-}
-
-void kheap_map_page()
-{
-    uintptr_t phys = pmm_alloc();
-    paging_map_page(kernel_pml4, end, phys, PTE_PRESENT | PTE_WRITABLE | PTE_NOEXEC);
-    end += PAGE_SIZE;
-    //DEBUG("Mapped first kheap page");
-}
-
 void kheap_init()
 {
     kheap_start = ALIGN_UP(kernel_virt_base + KERNEL_SIZE, PAGE_SIZE);
-    end = kheap_start;
+    
+    size_t heap_pages = ALIGN_UP(KHEAP_SIZE, PAGE_SIZE) / PAGE_SIZE;
+    DEBUG("Mapping %d kernel heap pages at 0x%p", heap_pages, kheap_start);
 
-    // At least 1 page must be mapped for it to work
+    uintptr_t current_addr = kheap_start;
-    kheap_map_page();
+
+    // Map/alloc enough pages for heap (KHEAP_SIZE)
+    for (size_t i=0; i<heap_pages; i++)
+    {
+        uintptr_t phys = pmm_alloc();
+        if (phys == 0)
+        {
+            panic(NULL, "Not enough memory available to initialize kernel heap.");
+        }
+
+        paging_map_page(kernel_pml4, current_addr, phys, PTE_PRESENT | PTE_WRITABLE);
+        current_addr += PAGE_SIZE;
+    }
+
+    end = current_addr;
 
     // Give linked list head its properties
     head = (struct heap_block_t*)kheap_start;
-    head->size = PAGE_SIZE - sizeof(struct heap_block_t);
+    head->size = (end-kheap_start) - sizeof(struct heap_block_t);
     head->free = true;
     head->next = NULL;
-    DEBUG("kernel heap initialized, head=0x%p, max_size=%u bytes", head, KHEAP_SIZE);
+    DEBUG("Kernel heap initialized, head=0x%p, size=%u bytes", head, head->size);
 }
 
 void* kmalloc(size_t size)
@@ -73,12 +69,12 @@ void* kmalloc(size_t size)
         if (curr->free && curr->size >= size)
         {
             // We split the block if it is big enough
-            if (curr->size >= size + BLOCK_MIN_SIZE)
+            if (curr->size >= size + sizeof(struct heap_block_t) + 16)
             {
                 //struct heap_block_t* new_block = (struct heap_block_t*)((uintptr_t)curr + sizeof(struct heap_block_t) + size);
-                struct heap_block_t* split = (struct heap_block_t*)((uintptr_t)curr + sizeof(*curr) + size);
+                struct heap_block_t* split = (struct heap_block_t*)((uintptr_t)curr + sizeof(struct heap_block_t) + size);
                 
-                split->size = curr->size - size - sizeof(*curr);
+                split->size = curr->size - size - sizeof(struct heap_block_t);
                 split->free = true;
                 split->next = curr->next;
 
@@ -94,25 +90,12 @@ void* kmalloc(size_t size)
         curr = curr->next;
     }
 
-    // If we're here it means we didn't have enough memory
+    // No growing. If we're here it means the initial pool
-    // for the block allocation. So we will allocate more..
+    // wasn't sufficient. Too bad.
-    uintptr_t old_end = end;
+    DEBUG("Kernel heap is OUT OF MEMORY!");
-    kheap_grow(size + sizeof(struct heap_block_t));
+    // if we were terrorists maybe we should panic
-
+    // or just wait for others to free stuff?
-    struct heap_block_t* block = (struct heap_block_t*)old_end;
+    return NULL;
-    block->size = ALIGN_UP(end - old_end - sizeof(struct heap_block_t), 16);
-    block->free = true;
-    block->next = NULL;
-
-    // Put the block at the end of the list
-    curr = head;
-    while (curr->next)
-    {
-        curr = curr->next;
-    }
-    curr->next = block;
-
-    return kmalloc(size);
 }
 
 void kfree(void* ptr)

src/mem/heap/kheap.h

@@ -14,13 +14,15 @@
 
 #include <stdbool.h>
 #include <stddef.h>
+#include <stdint.h>
 
 struct heap_block_t
 {
     size_t size;
-    bool free;
+    bool free; // 1byte
+    uint8_t reserved[7]; // (7+1 = 8 bytes)
     struct heap_block_t* next;
-};
+} __attribute__((aligned(16)));
 
 void kheap_init();
 void* kmalloc(size_t size);

src/mem/paging/paging.c

@@ -123,7 +123,7 @@ void paging_init()
     DEBUG("Kernel lives at virt=0x%p phys=0x%p", kernel_virt_base, kernel_phys_base);
 
     kernel_pml4 = alloc_page_table();
-
+    
     // for debug
     uint64_t page_count = 0;
 

src/sched/scheduler.c

@@ -21,6 +21,18 @@ void scheduler_init()
 
 struct cpu_status_t* scheduler_schedule(struct cpu_status_t* context)
 {
+    if (context == NULL)
+    {
+        panic(NULL, "Scheduler called with NULL context"); 
+    }
+
+    if (current_process == NULL)
+    {
+        // Wtf happened
+        current_process = processes_list;
+        //panic(NULL, "Scheduler called without current process");
+    }
+
     current_process->context = context;
     //current_process->status = READY;
 

src/sched/task.S

@@ -1,7 +0,0 @@
-; Task (process) switching
-
-bits 64
-
-global switch_to_task
-switch_to_task:
-