arm64: stacktrace: make struct stackframe private to stacktrace.c

Now that arm64 uses arch_stack_walk() consistently, struct stackframe is
only used within stacktrace.c. To make it easier to read and maintain
this code, it would be nicer if the definition were there too.

Move the definition into stacktrace.c.

There should be no functional change as a result of this patch.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Madhavan T. Venkataraman <madvenka@linux.microsoft.com>
Cc: Mark Brown <broonie@kernel.org>
Cc: Will Deacon <will@kernel.org>
Reviewed-by: Madhavan T. Venkataraman <madvenka@linux.microsoft.com>
Reviwed-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Kalesh Singh <kaleshsingh@google.com> for the series.
Link: https://lore.kernel.org/r/20220413145910.3060139-4-mark.rutland@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

1 files changed, 32 insertions, 0 deletions

diff --git a/arch/arm64/kernel/stacktrace.c b/arch/arm64/kernel/stacktrace.c
index 08af9ca9a845..073d0941a5b6 100644
--- a/arch/arm64/kernel/stacktrace.c
+++ b/arch/arm64/kernel/stacktrace.c
@@ -18,6 +18,38 @@
 #include <asm/stack_pointer.h>
 #include <asm/stacktrace.h>
 
+/*
+ * A snapshot of a frame record or fp/lr register values, along with some
+ * accounting information necessary for robust unwinding.
+ *
+ * @fp:          The fp value in the frame record (or the real fp)
+ * @pc:          The lr value in the frame record (or the real lr)
+ *
+ * @stacks_done: Stacks which have been entirely unwound, for which it is no
+ *               longer valid to unwind to.
+ *
+ * @prev_fp:     The fp that pointed to this frame record, or a synthetic value
+ *               of 0. This is used to ensure that within a stack, each
+ *               subsequent frame record is at an increasing address.
+ * @prev_type:   The type of stack this frame record was on, or a synthetic
+ *               value of STACK_TYPE_UNKNOWN. This is used to detect a
+ *               transition from one stack to another.
+ *
+ * @kr_cur:      When KRETPROBES is selected, holds the kretprobe instance
+ *               associated with the most recently encountered replacement lr
+ *               value.
+ */
+struct stackframe {
+	unsigned long fp;
+	unsigned long pc;
+	DECLARE_BITMAP(stacks_done, __NR_STACK_TYPES);
+	unsigned long prev_fp;
+	enum stack_type prev_type;
+#ifdef CONFIG_KRETPROBES
+	struct llist_node *kr_cur;
+#endif
+};
+
 static notrace void start_backtrace(struct stackframe *frame, unsigned long fp,
 				    unsigned long pc)
 {