backtrace

2 files changed, 48 insertions, 0 deletions

diff --git a/kernel/lib/backtrace.c b/kernel/lib/backtrace.c
new file mode 100644
index 0000000..fb708b2
--- /dev/null
+++ b/kernel/lib/backtrace.c
@@ -0,0 +1,46 @@
+#include <lib.h>
+
+struct stackframe {
+	struct stackframe *rbp;
+	void *rip;
+};
+
+size_t backtrace(void **dst, size_t len)
+{
+	struct stackframe *rbp;
+	__asm__("mov %%rbp, %0" : "=r"(rbp));
+	return backtrace_ex(dst, len, rbp->rip, rbp->rbp);
+}
+
+size_t backtrace_ex(void **dst, size_t len, void *ip, void *bp)
+{
+	struct stackframe *frame = bp;
+	__asm__("mov %%rbp, %0" : "=r"(frame));
+	if (len > 0) {
+		dst[0] = ip;
+	}
+	size_t i;
+	for (i = 1; frame && i < len; i++) {
+		dst[i] = frame->rip;
+		frame = frame->rbp;
+	}
+	return i;
+}
+
+void log_backtrace(void)
+{
+	struct stackframe *rbp;
+	__asm__("mov %%rbp, %0" : "=r"(rbp));
+	log_backtrace_ex(rbp->rip, rbp->rbp);
+}
+
+void log_backtrace_ex(void *ip, void *bp)
+{
+	struct stackframe *frame = bp;
+	kputs("Stack trace:\n");
+	kprintf("  %p\n", ip);
+	while (frame) {
+		kprintf("  %p\n", frame->rip);
+		frame = frame->rbp;
+	}
+}
diff --git a/kernel/lib/panic.c b/kernel/lib/panic.c
index 5381041..d3db908 100644
--- a/kernel/lib/panic.c
+++ b/kernel/lib/panic.c
@@ -1,3 +1,4 @@
+#include "lib/klib.h"
 #include <lib.h>
 #include <stdarg.h>
 #include <comus/asm.h>
@@ -10,6 +11,7 @@ __attribute__((noreturn)) void panic(const char *format, ...)
 	kprintf("\n\n!!! PANIC !!!\n");
 	kvprintf(format, list);
 	kprintf("\n\n");
+	log_backtrace();
 
 	while (1)
 		halt();