// SPDX-License-Identifier: GPL-2.0-only
#include <linux/sched.h>
#include <linux/sched/debug.h>
#include <linux/stacktrace.h>
#include <linux/thread_info.h>
#include <linux/ftrace.h>
#include <linux/export.h>
#include <asm/ptrace.h>
#include <asm/stacktrace.h>

#include "kstack.h"

static void __save_stack_trace(struct thread_info *tp,
                               struct stack_trace *trace,
                               bool skip_sched)
{
        unsigned long ksp, fp;
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
        struct task_struct *t;
        int graph = 0;
#endif

        if (tp == current_thread_info()) {
                stack_trace_flush();
                __asm__ __volatile__("mov %%fp, %0" : "=r" (ksp));
        } else {
                ksp = tp->ksp;
        }

        fp = ksp + STACK_BIAS;
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
        t = tp->task;
#endif
        do {
                struct sparc_stackf *sf;
                struct pt_regs *regs;
                unsigned long pc;

                if (!kstack_valid(tp, fp))
                        break;

                sf = (struct sparc_stackf *) fp;
                regs = (struct pt_regs *) (sf + 1);

                if (kstack_is_trap_frame(tp, regs)) {
                        if (!(regs->tstate & TSTATE_PRIV))
                                break;
                        pc = regs->tpc;
                        fp = regs->u_regs[UREG_I6] + STACK_BIAS;
                } else {
                        pc = sf->callers_pc;
                        fp = (unsigned long)sf->fp + STACK_BIAS;
                }

                if (trace->skip > 0)
                        trace->skip--;
                else if (!skip_sched || !in_sched_functions(pc)) {
                        trace->entries[trace->nr_entries++] = pc;
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
                        if ((pc + 8UL) == (unsigned long) &return_to_handler) {
                                struct ftrace_ret_stack *ret_stack;
                                ret_stack = ftrace_graph_get_ret_stack(t,
                                                                       graph);
                                if (ret_stack) {
                                        pc = ret_stack->ret;
                                        if (trace->nr_entries <
                                            trace->max_entries)
                                                trace->entries[trace->nr_entries++] = pc;
                                        graph++;
                                }
                        }
#endif
                }
        } while (trace->nr_entries < trace->max_entries);
}

void save_stack_trace(struct stack_trace *trace)
{
        __save_stack_trace(current_thread_info(), trace, false);
}
EXPORT_SYMBOL_GPL(save_stack_trace);

void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
{
        struct thread_info *tp = task_thread_info(tsk);

        __save_stack_trace(tp, trace, true);
}
EXPORT_SYMBOL_GPL(save_stack_trace_tsk);