// SPDX-License-Identifier: GPL-2.0
/*
 * bootstr.c:  Boot string/argument acquisition from the PROM.
 *
 * Copyright(C) 1995 David S. Miller (davem@caip.rutgers.edu)
 */

#include <linux/string.h>
#include <asm/oplib.h>
#include <linux/init.h>

#define BARG_LEN  256
static char barg_buf[BARG_LEN] = { 0 };
static char fetched __initdata = 0;

char * __init
prom_getbootargs(void)
{
        int iter;
        char *cp, *arg;

        /* This check saves us from a panic when bootfd patches args. */
        if (fetched) {
                return barg_buf;
        }

        switch (prom_vers) {
        case PROM_V0:
                cp = barg_buf;
                /* Start from 1 and go over fd(0,0,0)kernel */
                for (iter = 1; iter < 8; iter++) {
                        arg = (*(romvec->pv_v0bootargs))->argv[iter];
                        if (arg == NULL)
                                break;
                        while (*arg != 0) {
                                /* Leave place for space and null. */
                                if (cp >= barg_buf + BARG_LEN - 2)
                                        /* We might issue a warning here. */
                                        break;
                                *cp++ = *arg++;
                        }
                        *cp++ = ' ';
                        if (cp >= barg_buf + BARG_LEN - 1)
                                /* We might issue a warning here. */
                                break;
                }
                *cp = 0;
                break;
        case PROM_V2:
        case PROM_V3:
                /*
                 * V3 PROM cannot supply as with more than 128 bytes
                 * of an argument. But a smart bootstrap loader can.
                 */
                strscpy(barg_buf, *romvec->pv_v2bootargs.bootargs, sizeof(barg_buf));
                break;
        default:
                break;
        }

        fetched = 1;
        return barg_buf;
}