1 files changed, 150 insertions, 10 deletions

diff --git a/arch/arm64/kernel/stacktrace.c b/arch/arm64/kernel/stacktrace.c
index 2729faaee4b4..1d9d51d7627f 100644
--- a/arch/arm64/kernel/stacktrace.c
+++ b/arch/arm64/kernel/stacktrace.c
@@ -20,6 +20,22 @@
 #include <asm/stack_pointer.h>
 #include <asm/stacktrace.h>
 
+enum kunwind_source {
+	KUNWIND_SOURCE_UNKNOWN,
+	KUNWIND_SOURCE_FRAME,
+	KUNWIND_SOURCE_CALLER,
+	KUNWIND_SOURCE_TASK,
+	KUNWIND_SOURCE_REGS_PC,
+};
+
+union unwind_flags {
+	unsigned long	all;
+	struct {
+		unsigned long	fgraph : 1,
+				kretprobe : 1;
+	};
+};
+
 /*
  * Kernel unwind state
  *
@@ -37,6 +53,9 @@ struct kunwind_state {
 #ifdef CONFIG_KRETPROBES
 	struct llist_node *kr_cur;
 #endif
+	enum kunwind_source source;
+	union unwind_flags flags;
+	struct pt_regs *regs;
 };
 
 static __always_inline void
@@ -45,6 +64,9 @@ kunwind_init(struct kunwind_state *state,
 {
 	unwind_init_common(&state->common);
 	state->task = task;
+	state->source = KUNWIND_SOURCE_UNKNOWN;
+	state->flags.all = 0;
+	state->regs = NULL;
 }
 
 /*
@@ -60,8 +82,10 @@ kunwind_init_from_regs(struct kunwind_state *state,
 {
 	kunwind_init(state, current);
 
+	state->regs = regs;
 	state->common.fp = regs->regs[29];
 	state->common.pc = regs->pc;
+	state->source = KUNWIND_SOURCE_REGS_PC;
 }
 
 /*
@@ -79,6 +103,7 @@ kunwind_init_from_caller(struct kunwind_state *state)
 
 	state->common.fp = (unsigned long)__builtin_frame_address(1);
 	state->common.pc = (unsigned long)__builtin_return_address(0);
+	state->source = KUNWIND_SOURCE_CALLER;
 }
 
 /*
@@ -99,6 +124,7 @@ kunwind_init_from_task(struct kunwind_state *state,
 
 	state->common.fp = thread_saved_fp(task);
 	state->common.pc = thread_saved_pc(task);
+	state->source = KUNWIND_SOURCE_TASK;
 }
 
 static __always_inline int
@@ -111,9 +137,12 @@ kunwind_recover_return_address(struct kunwind_state *state)
 		orig_pc = ftrace_graph_ret_addr(state->task, &state->graph_idx,
 						state->common.pc,
 						(void *)state->common.fp);
-		if (WARN_ON_ONCE(state->common.pc == orig_pc))
+		if (state->common.pc == orig_pc) {
+			WARN_ON_ONCE(state->task == current);
 			return -EINVAL;
+		}
 		state->common.pc = orig_pc;
+		state->flags.fgraph = 1;
 	}
 #endif /* CONFIG_FUNCTION_GRAPH_TRACER */
 
@@ -124,12 +153,95 @@ kunwind_recover_return_address(struct kunwind_state *state)
 						  (void *)state->common.fp,
 						  &state->kr_cur);
 		state->common.pc = orig_pc;
+		state->flags.kretprobe = 1;
 	}
 #endif /* CONFIG_KRETPROBES */
 
 	return 0;
 }
 
+static __always_inline
+int kunwind_next_regs_pc(struct kunwind_state *state)
+{
+	struct stack_info *info;
+	unsigned long fp = state->common.fp;
+	struct pt_regs *regs;
+
+	regs = container_of((u64 *)fp, struct pt_regs, stackframe.record.fp);
+
+	info = unwind_find_stack(&state->common, (unsigned long)regs, sizeof(*regs));
+	if (!info)
+		return -EINVAL;
+
+	unwind_consume_stack(&state->common, info, (unsigned long)regs,
+			     sizeof(*regs));
+
+	state->regs = regs;
+	state->common.pc = regs->pc;
+	state->common.fp = regs->regs[29];
+	state->regs = NULL;
+	state->source = KUNWIND_SOURCE_REGS_PC;
+	return 0;
+}
+
+static __always_inline int
+kunwind_next_frame_record_meta(struct kunwind_state *state)
+{
+	struct task_struct *tsk = state->task;
+	unsigned long fp = state->common.fp;
+	struct frame_record_meta *meta;
+	struct stack_info *info;
+
+	info = unwind_find_stack(&state->common, fp, sizeof(*meta));
+	if (!info)
+		return -EINVAL;
+
+	meta = (struct frame_record_meta *)fp;
+	switch (READ_ONCE(meta->type)) {
+	case FRAME_META_TYPE_FINAL:
+		if (meta == &task_pt_regs(tsk)->stackframe)
+			return -ENOENT;
+		WARN_ON_ONCE(tsk == current);
+		return -EINVAL;
+	case FRAME_META_TYPE_PT_REGS:
+		return kunwind_next_regs_pc(state);
+	default:
+		WARN_ON_ONCE(tsk == current);
+		return -EINVAL;
+	}
+}
+
+static __always_inline int
+kunwind_next_frame_record(struct kunwind_state *state)
+{
+	unsigned long fp = state->common.fp;
+	struct frame_record *record;
+	struct stack_info *info;
+	unsigned long new_fp, new_pc;
+
+	if (fp & 0x7)
+		return -EINVAL;
+
+	info = unwind_find_stack(&state->common, fp, sizeof(*record));
+	if (!info)
+		return -EINVAL;
+
+	record = (struct frame_record *)fp;
+	new_fp = READ_ONCE(record->fp);
+	new_pc = READ_ONCE(record->lr);
+
+	if (!new_fp && !new_pc)
+		return kunwind_next_frame_record_meta(state);
+
+	unwind_consume_stack(&state->common, info, fp, sizeof(*record));
+
+	state->common.fp = new_fp;
+	state->common.pc = new_pc;
+	state->source = KUNWIND_SOURCE_FRAME;
+
+	return 0;
+}
+
 /*
  * Unwind from one frame record (A) to the next frame record (B).
  *
@@ -140,15 +252,21 @@ kunwind_recover_return_address(struct kunwind_state *state)
 static __always_inline int
 kunwind_next(struct kunwind_state *state)
 {
-	struct task_struct *tsk = state->task;
-	unsigned long fp = state->common.fp;
 	int err;
 
-	/* Final frame; nothing to unwind */
-	if (fp == (unsigned long)task_pt_regs(tsk)->stackframe)
-		return -ENOENT;
+	state->flags.all = 0;
+
+	switch (state->source) {
+	case KUNWIND_SOURCE_FRAME:
+	case KUNWIND_SOURCE_CALLER:
+	case KUNWIND_SOURCE_TASK:
+	case KUNWIND_SOURCE_REGS_PC:
+		err = kunwind_next_frame_record(state);
+		break;
+	default:
+		err = -EINVAL;
+	}
 
-	err = unwind_next_frame_record(&state->common);
 	if (err)
 		return err;
 
@@ -294,10 +412,32 @@ noinline noinstr void arch_bpf_stack_walk(bool (*consume_entry)(void *cookie, u6
 	kunwind_stack_walk(arch_bpf_unwind_consume_entry, &data, current, NULL);
 }
 
-static bool dump_backtrace_entry(void *arg, unsigned long where)
+static const char *state_source_string(const struct kunwind_state *state)
 {
+	switch (state->source) {
+	case KUNWIND_SOURCE_FRAME:	return NULL;
+	case KUNWIND_SOURCE_CALLER:	return "C";
+	case KUNWIND_SOURCE_TASK:	return "T";
+	case KUNWIND_SOURCE_REGS_PC:	return "P";
+	default:			return "U";
+	}
+}
+
+static bool dump_backtrace_entry(const struct kunwind_state *state, void *arg)
+{
+	const char *source = state_source_string(state);
+	union unwind_flags flags = state->flags;
+	bool has_info = source || flags.all;
 	char *loglvl = arg;
-	printk("%s %pSb\n", loglvl, (void *)where);
+
+	printk("%s %pSb%s%s%s%s%s\n", loglvl,
+		(void *)state->common.pc,
+		has_info ? " (" : "",
+		source ? source : "",
+		flags.fgraph ? "F" : "",
+		flags.kretprobe ? "K" : "",
+		has_info ? ")" : "");
+
 	return true;
 }
 
@@ -316,7 +456,7 @@ void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk,
 		return;
 
 	printk("%sCall trace:\n", loglvl);
-	arch_stack_walk(dump_backtrace_entry, (void *)loglvl, tsk, regs);
+	kunwind_stack_walk(dump_backtrace_entry, (void *)loglvl, tsk, regs);
 
 	put_task_stack(tsk);
 }