debug macros in std

include/std.h

@@ -31,4 +31,17 @@ int checkStringLength(const char *string);
 // Formatted output
 void myprintf(const char *format, ...);
 
+// Debug helpers
+#define PANIC(msg) panic(__FILE__, __LINE__, msg)
+#define ASSERT(cond) do {\
+  if (!(cond)) {\
+    PANIC("assertion failed: " #cond);\
+  }\
+} while (0)
+#define TODO() PANIC("not implemented")
+#define UNREACHABLE() PANIC("unreachable")
+// don't use this directly, use the macros above
+__attribute__ ((noreturn))
+void panic(const char *file, unsigned int line, const char *msg);
+
 #endif // KARLOS_UTILITY_H

src/kernel.c

@@ -82,7 +82,7 @@ void _start() {
 
     uint16_t bdf;
     if (pci_search(0x1AF4, 0x1001, &bdf) && pci_search(0x1AF4, 0x1042, &bdf)) {
-        panic("couldn't find virtio_blk device!");
+        PANIC("couldn't find virtio_blk device!");
     }
     myprintf("found virtio_blk device at bdf %u .", bdf);
   // read BARs
@@ -111,7 +111,7 @@ void _start() {
       */
 
   // hang for now
-    panic("end of kernel");
+    PANIC("end of kernel");
 }
 
 /**************************

src/pci.c

@@ -8,9 +8,7 @@
 #define PCI_CONFIG_DATA_PORT 0xCFC
 
 uint16_t pci_bdf_make(uint8_t bus, uint8_t dev, uint8_t fun) {
-    if (dev >= 32 || fun >= 8) {
-        panic("pci_bdf_make");
-    }
+    ASSERT(dev < 32 && fun < 8);
     return ((uint16_t)bus << 8) | ((uint16_t)dev << 3) | (uint16_t)fun;
 }
 
@@ -34,9 +32,7 @@ void pci_config_write_u32(uint16_t bdf, uint8_t offset, uint32_t value) {
 }
 
 struct pci_bar_desc pci_bar_desc_read(uint16_t bdf, uint8_t barnum) {
-    if (barnum >= 6) {
-        panic("pci_config_read_bar");
-    }
+    ASSERT(barnum < 6);
 
   // get basic information
   // https://en.wikipedia.org/wiki/PCI_configuration_space
@@ -46,9 +42,7 @@ struct pci_bar_desc pci_bar_desc_read(uint16_t bdf, uint8_t barnum) {
     desc.type = bar & 0x1;
     if (desc.type == PCI_BAR_TYPE_MEM) {
         desc.locatable = (bar >> 1) & 0x3;
-        if (desc.locatable == 3) {
-            panic("pci_config_read_bar");
-        }
+        ASSERT(desc.locatable != 3);
         desc.prefetchable = (bar >> 3) & 0x1;
         desc.address = bar & 0xfffffff0;
     } else {

src/std.c

@@ -527,3 +527,11 @@ void myprintf(const char *format, ...) {
     }
     va_end(args);
 }
+
+/* --- Debug helpers --- */
+__attribute__((noreturn)) void panic(const char *file, unsigned int line, const char *msg) {
+    myprintf("PANIC@%s:%d: %s\n", file, line, msg);
+    while (1) {
+        // loop forever
+    }
+}