// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2001 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
 * Copyright (C) 2013 Richard Weinberger <richard@nod.at>
 * Copyright (C) 2014 Google Inc., Author: Daniel Walter <dwalter@google.com>
 */

#include <linux/kallsyms.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/stacktrace.h>
#include <linux/module.h>
#include <linux/uaccess.h>
#include <asm/stacktrace.h>

void dump_trace(struct task_struct *tsk,
                const struct stacktrace_ops *ops,
                void *data)
{
        int reliable = 0;
        unsigned long *sp, bp, addr;
        struct pt_regs *segv_regs = tsk->thread.segv_regs;
        struct stack_frame *frame;

        bp = get_frame_pointer(tsk, segv_regs);
        sp = get_stack_pointer(tsk, segv_regs);

        frame = (struct stack_frame *)bp;
        while (((long) sp & (THREAD_SIZE-1)) != 0) {
                addr = READ_ONCE_NOCHECK(*sp);
                if (__kernel_text_address(addr)) {
                        reliable = 0;
                        if ((unsigned long) sp == bp + sizeof(long)) {
                                frame = frame ? frame->next_frame : NULL;
                                bp = (unsigned long)frame;
                                reliable = 1;
                        }
                        ops->address(data, addr, reliable);
                }
                sp++;
        }
}

static void save_addr(void *data, unsigned long address, int reliable)
{
        struct stack_trace *trace = data;

        if (!reliable)
                return;
        if (trace->nr_entries >= trace->max_entries)
                return;

        trace->entries[trace->nr_entries++] = address;
}

static const struct stacktrace_ops dump_ops = {
        .address = save_addr
};

static void __save_stack_trace(struct task_struct *tsk, struct stack_trace *trace)
{
        dump_trace(tsk, &dump_ops, trace);
}

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

void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
{
        __save_stack_trace(tsk, trace);
}
EXPORT_SYMBOL_GPL(save_stack_trace_tsk);