1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * bootstr.c: Boot string/argument acquisition from the PROM. 4 * 5 * Copyright(C) 1995 David S. Miller (davem@caip.rutgers.edu) 6 */ 7 8 #include <linux/string.h> 9 #include <asm/oplib.h> 10 #include <linux/init.h> 11 12 #define BARG_LEN 256 13 static char barg_buf[BARG_LEN] = { 0 }; 14 static char fetched __initdata = 0; 15 16 char * __init 17 prom_getbootargs(void) 18 { 19 int iter; 20 char *cp, *arg; 21 22 /* This check saves us from a panic when bootfd patches args. */ 23 if (fetched) { 24 return barg_buf; 25 } 26 27 switch (prom_vers) { 28 case PROM_V0: 29 cp = barg_buf; 30 /* Start from 1 and go over fd(0,0,0)kernel */ 31 for (iter = 1; iter < 8; iter++) { 32 arg = (*(romvec->pv_v0bootargs))->argv[iter]; 33 if (arg == NULL) 34 break; 35 while (*arg != 0) { 36 /* Leave place for space and null. */ 37 if (cp >= barg_buf + BARG_LEN - 2) 38 /* We might issue a warning here. */ 39 break; 40 *cp++ = *arg++; 41 } 42 *cp++ = ' '; 43 if (cp >= barg_buf + BARG_LEN - 1) 44 /* We might issue a warning here. */ 45 break; 46 } 47 *cp = 0; 48 break; 49 case PROM_V2: 50 case PROM_V3: 51 /* 52 * V3 PROM cannot supply as with more than 128 bytes 53 * of an argument. But a smart bootstrap loader can. 54 */ 55 strlcpy(barg_buf, *romvec->pv_v2bootargs.bootargs, sizeof(barg_buf)); 56 break; 57 default: 58 break; 59 } 60 61 fetched = 1; 62 return barg_buf; 63 } 64