arm64: stacktrace: move dump_backtrace() to kunwind_stack_walk()

Currently dump_backtrace() can only print the PC value at each step of
the unwind, as this is all the information that arch_stack_walk()
passes to the dump_backtrace_entry() callback.

In future we'd like to print some additional information, such as the
origin of entries (e.g. PC, LR, FP) and/or the reliability thereof.

In preparation for doing so, this patch moves dump_backtrace() over to
kunwind_stack_walk(), which passes the full kunwind_state to the
callback.

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

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Reviewed-by: Puranjay Mohan <puranjay12@gmail.com>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Josh Poimboeuf <jpoimboe@kernel.org>
Cc: Kalesh Singh <kaleshsingh@google.com>
Cc: Madhavan T. Venkataraman <madvenka@linux.microsoft.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20241017092538.1859841-7-mark.rutland@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

Author: mrutland-arm

arch/arm64/kernel/stacktrace.c

@@ -294,10 +294,10 @@ 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 bool dump_backtrace_entry(const struct kunwind_state *state, void *arg)
 {
 	char *loglvl = arg;
-	printk("%s %pSb\n", loglvl, (void *)where);
+	printk("%s %pSb\n", loglvl, (void *)state->common.pc);
 	return true;
 }
 
@@ -316,7 +316,7 @@ 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);
 }