1 files changed, 120 insertions, 0 deletions
diff --git a/arch/powerpc/oprofile/backtrace.c b/arch/powerpc/oprofile/backtrace.c
new file mode 100644
index 000000000..9db7ada79
--- /dev/null
+++ b/arch/powerpc/oprofile/backtrace.c
@@ -0,0 +1,120 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/**
+ * Copyright (C) 2005 Brian Rogan <bcr6@cornell.edu>, IBM
+ *
+**/
+
+#include <linux/time.h>
+#include <linux/oprofile.h>
+#include <linux/sched.h>
+#include <asm/processor.h>
+#include <linux/uaccess.h>
+#include <linux/compat.h>
+#include <asm/oprofile_impl.h>
+
+#define STACK_SP(STACK)		*(STACK)
+
+#define STACK_LR64(STACK)	*((unsigned long *)(STACK) + 2)
+#define STACK_LR32(STACK)	*((unsigned int *)(STACK) + 1)
+
+#ifdef CONFIG_PPC64
+#define STACK_LR(STACK)		STACK_LR64(STACK)
+#else
+#define STACK_LR(STACK)		STACK_LR32(STACK)
+#endif
+
+static unsigned int user_getsp32(unsigned int sp, int is_first)
+{
+	unsigned int stack_frame[2];
+	void __user *p = compat_ptr(sp);
+
+	/*
+	 * The most likely reason for this is that we returned -EFAULT,
+	 * which means that we've done all that we can do from
+	 * interrupt context.
+	 */
+	if (copy_from_user_nofault(stack_frame, (void __user *)p,
+			sizeof(stack_frame)))
+		return 0;
+
+	if (!is_first)
+		oprofile_add_trace(STACK_LR32(stack_frame));
+
+	/*
+	 * We do not enforce increasing stack addresses here because
+	 * we may transition to a different stack, eg a signal handler.
+	 */
+	return STACK_SP(stack_frame);
+}
+
+#ifdef CONFIG_PPC64
+static unsigned long user_getsp64(unsigned long sp, int is_first)
+{
+	unsigned long stack_frame[3];
+
+	if (copy_from_user_nofault(stack_frame, (void __user *)sp,
+			sizeof(stack_frame)))
+		return 0;
+
+	if (!is_first)
+		oprofile_add_trace(STACK_LR64(stack_frame));
+
+	return STACK_SP(stack_frame);
+}
+#endif
+
+static unsigned long kernel_getsp(unsigned long sp, int is_first)
+{
+	unsigned long *stack_frame = (unsigned long *)sp;
+
+	if (!validate_sp(sp, current, STACK_FRAME_OVERHEAD))
+		return 0;
+
+	if (!is_first)
+		oprofile_add_trace(STACK_LR(stack_frame));
+
+	/*
+	 * We do not enforce increasing stack addresses here because
+	 * we might be transitioning from an interrupt stack to a kernel
+	 * stack. validate_sp() is designed to understand this, so just
+	 * use it.
+	 */
+	return STACK_SP(stack_frame);
+}
+
+void op_powerpc_backtrace(struct pt_regs * const regs, unsigned int depth)
+{
+	unsigned long sp = regs->gpr[1];
+	int first_frame = 1;
+
+	/* We ditch the top stackframe so need to loop through an extra time */
+	depth += 1;
+
+	if (!user_mode(regs)) {
+		while (depth--) {
+			sp = kernel_getsp(sp, first_frame);
+			if (!sp)
+				break;
+			first_frame = 0;
+		}
+	} else {
+#ifdef CONFIG_PPC64
+		if (!is_32bit_task()) {
+			while (depth--) {
+				sp = user_getsp64(sp, first_frame);
+				if (!sp)
+					break;
+				first_frame = 0;
+			}
+			return;
+		}
+#endif
+
+		while (depth--) {
+			sp = user_getsp32(sp, first_frame);
+			if (!sp)
+				break;
+			first_frame = 0;
+		}
+	}
+}