1 files changed, 61 insertions, 0 deletions
diff --git a/arch/alpha/kernel/stacktrace.c b/arch/alpha/kernel/stacktrace.c
new file mode 100644
index 000000000000..74d95f591039
--- /dev/null
+++ b/arch/alpha/kernel/stacktrace.c
@@ -0,0 +1,61 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/sched.h>
+#include <linux/sched/task_stack.h>
+#include <linux/stacktrace.h>
+#include <linux/kallsyms.h>
+
+#include <asm/thread_info.h>
+#include <asm/ptrace.h>
+
+static __always_inline unsigned long alpha_get_current_ksp(void)
+{
+	unsigned long sp;
+
+	asm volatile("mov $30, %0" : "=r"(sp));
+	return sp;
+}
+
+static void alpha_scan_kernel_stack(unsigned long ksp,
+				    stack_trace_consume_fn consume_entry,
+				    void *cookie)
+{
+	unsigned long *p = (unsigned long *)ksp;
+
+	if (unlikely(ksp & (sizeof(unsigned long) - 1)))
+		return;
+
+	while (!kstack_end(p)) {
+		unsigned long addr = READ_ONCE_NOCHECK(*p++);
+
+		if (!__kernel_text_address(addr))
+			continue;
+
+		if (!consume_entry(cookie, addr))
+			break;
+	}
+}
+
+noinline void arch_stack_walk(stack_trace_consume_fn consume_entry,
+				      void *cookie,
+				      struct task_struct *task,
+				      struct pt_regs *regs)
+{
+	unsigned long ksp;
+
+	if (!task)
+		task = current;
+
+	if (regs && task == current) {
+		/*
+		 * pt_regs is stored on the kernel stack; regs+1 matches
+		 * what arch/alpha/kernel/traps.c uses as the trace start.
+		 */
+		ksp = (unsigned long)(regs + 1);
+	} else if (task == current) {
+		ksp = alpha_get_current_ksp();
+	} else {
+		ksp = task_thread_info(task)->pcb.ksp;
+	}
+
+	alpha_scan_kernel_stack(ksp, consume_entry, cookie);
+}