From f51e7146740514347d6c5526a2c393e224a19c0d Mon Sep 17 00:00:00 2001
From: Kalesh Singh <kaleshsingh@google.com>
Date: Tue, 26 Jul 2022 00:37:38 -0700
Subject: arm64: stacktrace: Factor out common unwind()

Move unwind() to stacktrace/common.h, and as a result
the kernel unwind_next() to asm/stacktrace.h. This allow
reusing unwind() in the implementation of the nVHE HYP
stack unwinder, later in the series.

Signed-off-by: Kalesh Singh <kaleshsingh@google.com>
Reviewed-by: Fuad Tabba <tabba@google.com>
Reviewed-by: Mark Brown <broonie@kernel.org>
Tested-by: Fuad Tabba <tabba@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20220726073750.3219117-6-kaleshsingh@google.com
---
 arch/arm64/kernel/stacktrace.c | 67 ------------------------------------------
 1 file changed, 67 deletions(-)

(limited to 'arch/arm64/kernel')

diff --git a/arch/arm64/kernel/stacktrace.c b/arch/arm64/kernel/stacktrace.c
index eef3cf6bf2d7..9fa60ee48499 100644
--- a/arch/arm64/kernel/stacktrace.c
+++ b/arch/arm64/kernel/stacktrace.c
@@ -7,14 +7,12 @@
 #include <linux/kernel.h>
 #include <linux/export.h>
 #include <linux/ftrace.h>
-#include <linux/kprobes.h>
 #include <linux/sched.h>
 #include <linux/sched/debug.h>
 #include <linux/sched/task_stack.h>
 #include <linux/stacktrace.h>
 
 #include <asm/irq.h>
-#include <asm/pointer_auth.h>
 #include <asm/stack_pointer.h>
 #include <asm/stacktrace.h>
 
@@ -69,71 +67,6 @@ static inline void unwind_init_from_task(struct unwind_state *state,
 	state->pc = thread_saved_pc(task);
 }
 
-/*
- * Unwind from one frame record (A) to the next frame record (B).
- *
- * We terminate early if the location of B indicates a malformed chain of frame
- * records (e.g. a cycle), determined based on the location and fp value of A
- * and the location (but not the fp value) of B.
- */
-static int notrace unwind_next(struct unwind_state *state)
-{
-	struct task_struct *tsk = state->task;
-	unsigned long fp = state->fp;
-	struct stack_info info;
-	int err;
-
-	/* Final frame; nothing to unwind */
-	if (fp == (unsigned long)task_pt_regs(tsk)->stackframe)
-		return -ENOENT;
-
-	err = unwind_next_common(state, &info, NULL);
-	if (err)
-		return err;
-
-	state->pc = ptrauth_strip_insn_pac(state->pc);
-
-#ifdef CONFIG_FUNCTION_GRAPH_TRACER
-	if (tsk->ret_stack &&
-		(state->pc == (unsigned long)return_to_handler)) {
-		unsigned long orig_pc;
-		/*
-		 * This is a case where function graph tracer has
-		 * modified a return address (LR) in a stack frame
-		 * to hook a function return.
-		 * So replace it to an original value.
-		 */
-		orig_pc = ftrace_graph_ret_addr(tsk, NULL, state->pc,
-						(void *)state->fp);
-		if (WARN_ON_ONCE(state->pc == orig_pc))
-			return -EINVAL;
-		state->pc = orig_pc;
-	}
-#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
-#ifdef CONFIG_KRETPROBES
-	if (is_kretprobe_trampoline(state->pc))
-		state->pc = kretprobe_find_ret_addr(tsk, (void *)state->fp, &state->kr_cur);
-#endif
-
-	return 0;
-}
-NOKPROBE_SYMBOL(unwind_next);
-
-static void notrace unwind(struct unwind_state *state,
-			   stack_trace_consume_fn consume_entry, void *cookie)
-{
-	while (1) {
-		int ret;
-
-		if (!consume_entry(cookie, state->pc))
-			break;
-		ret = unwind_next(state);
-		if (ret < 0)
-			break;
-	}
-}
-NOKPROBE_SYMBOL(unwind);
-
 static bool dump_backtrace_entry(void *arg, unsigned long where)
 {
 	char *loglvl = arg;
-- 
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