riscv: stacktrace: fix usage of ftrace_graph_ret_addr()

ftrace_graph_ret_addr() takes an `idx` integer pointer that is used to
optimize the stack unwinding. Pass it a valid pointer to utilize the
optimizations that might be available in the future.

The commit is making riscv's usage of ftrace_graph_ret_addr() match
x86_64.

Signed-off-by: Puranjay Mohan <puranjay@kernel.org>
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Link: https://lore.kernel.org/r/20240618145820.62112-1-puranjay@kernel.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>

diff --git a/arch/riscv/kernel/stacktrace.c b/arch/riscv/kernel/stacktrace.c
index 0d3f00eb0baee382295bc8594dd18fa493aa3558..10e311b2759d39d4480f1c3274c313c01b7efcb4 100644 (file)
--- a/arch/riscv/kernel/stacktrace.c
+++ b/arch/riscv/kernel/stacktrace.c
@@ -32,6 +32,7 @@ void notrace walk_stackframe(struct task_struct *task, struct pt_regs *regs,
                             bool (*fn)(void *, unsigned long), void *arg)
 {
        unsigned long fp, sp, pc;
+       int graph_idx = 0;
        int level = 0;
 
        if (regs) {
@@ -68,7 +69,7 @@ void notrace walk_stackframe(struct task_struct *task, struct pt_regs *regs,
                        pc = regs->ra;
                } else {
                        fp = frame->fp;
-                       pc = ftrace_graph_ret_addr(current, NULL, frame->ra,
+                       pc = ftrace_graph_ret_addr(current, &graph_idx, frame->ra,
                                                   &frame->ra);
                        if (pc == (unsigned long)ret_from_exception) {
                                if (unlikely(!__kernel_text_address(pc) || !fn(arg, pc)))