From 71270226b14733a4b1f2cde58ea9265caa50b38d Mon Sep 17 00:00:00 2001 From: Adrian Panella Date: Thu, 9 Mar 2017 09:37:17 +0100 Subject: [PATCH 67/69] generic: Mangle bootloader's kernel arguments The command-line arguments provided by the boot loader will be appended to a new device tree property: bootloader-args. If there is a property "append-rootblock" in DT under /chosen and a root= option in bootloaders command line it will be parsed and added to DT bootargs with the form: XX. Only command line ATAG will be processed, the rest of the ATAGs sent by bootloader will be ignored. This is usefull in dual boot systems, to get the current root partition without afecting the rest of the system. Signed-off-by: Adrian Panella --- arch/arm/Kconfig | 11 +++++ arch/arm/boot/compressed/atags_to_fdt.c | 72 ++++++++++++++++++++++++++++++++- init/main.c | 16 ++++++++ 3 files changed, 98 insertions(+), 1 deletion(-) --- a/arch/arm/Kconfig +++ b/arch/arm/Kconfig @@ -1824,6 +1824,17 @@ config ARM_ATAG_DTB_COMPAT_CMDLINE_EXTEN The command-line arguments provided by the boot loader will be appended to the the device tree bootargs property. +config ARM_ATAG_DTB_COMPAT_CMDLINE_MANGLE + bool "Append rootblock parsing bootloader's kernel arguments" + help + The command-line arguments provided by the boot loader will be + appended to a new device tree property: bootloader-args. + If there is a property "append-rootblock" in DT under /chosen + and a root= option in bootloaders command line it will be parsed + and added to DT bootargs with the form: XX. + Only command line ATAG will be processed, the rest of the ATAGs + sent by bootloader will be ignored. + endchoice config CMDLINE --- a/arch/arm/boot/compressed/atags_to_fdt.c +++ b/arch/arm/boot/compressed/atags_to_fdt.c @@ -4,6 +4,8 @@ #if defined(CONFIG_ARM_ATAG_DTB_COMPAT_CMDLINE_EXTEND) #define do_extend_cmdline 1 +#elif defined(CONFIG_ARM_ATAG_DTB_COMPAT_CMDLINE_MANGLE) +#define do_extend_cmdline 1 #else #define do_extend_cmdline 0 #endif @@ -67,6 +69,80 @@ static uint32_t get_cell_size(const void return cell_size; } +#if defined(CONFIG_ARM_ATAG_DTB_COMPAT_CMDLINE_MANGLE) +/** + * taken from arch/x86/boot/string.c + * local_strstr - Find the first substring in a %NUL terminated string + * @s1: The string to be searched + * @s2: The string to search for + */ +static char *local_strstr(const char *s1, const char *s2) +{ + size_t l1, l2; + + l2 = strlen(s2); + if (!l2) + return (char *)s1; + l1 = strlen(s1); + while (l1 >= l2) { + l1--; + if (!memcmp(s1, s2, l2)) + return (char *)s1; + s1++; + } + return NULL; +} + +static char *append_rootblock(char *dest, const char *str, int len, void *fdt) +{ + char *ptr, *end, *tmp; + char *root="root="; + char *find_rootblock; + int i, l; + const char *rootblock; + + find_rootblock = getprop(fdt, "/chosen", "find-rootblock", &l); + if(!find_rootblock) + find_rootblock = root; + + //ARM doesn't have __HAVE_ARCH_STRSTR, so it was copied from x86 + ptr = local_strstr(str, find_rootblock); + + if(!ptr) + return dest; + + end = strchr(ptr, ' '); + end = end ? (end - 1) : (strchr(ptr, 0) - 1); + + // Some boards ubi.mtd=XX,ZZZZ, so let's check for '," too. + tmp = strchr(ptr, ','); + + if(tmp) + end = end < tmp ? end : tmp - 1; + + //find partition number (assumes format root=/dev/mtdXX | /dev/mtdblockXX | yy:XX | ubi.mtd=XX,ZZZZ ) + for( i = 0; end >= ptr && *end >= '0' && *end <= '9'; end--, i++); + ptr = end + 1; + + /* if append-rootblock property is set use it to append to command line */ + rootblock = getprop(fdt, "/chosen", "append-rootblock", &l); + if(rootblock != NULL) { + if(*dest != ' ') { + *dest = ' '; + dest++; + len++; + } + if (len + l + i <= COMMAND_LINE_SIZE) { + memcpy(dest, rootblock, l); + dest += l - 1; + memcpy(dest, ptr, i); + dest += i; + } + } + return dest; +} +#endif + static void merge_fdt_bootargs(void *fdt, const char *fdt_cmdline) { char cmdline[COMMAND_LINE_SIZE]; @@ -86,12 +162,21 @@ static void merge_fdt_bootargs(void *fdt /* and append the ATAG_CMDLINE */ if (fdt_cmdline) { + +#if defined(CONFIG_ARM_ATAG_DTB_COMPAT_CMDLINE_MANGLE) + //save original bootloader args + //and append ubi.mtd with root partition number to current cmdline + setprop_string(fdt, "/chosen", "bootloader-args", fdt_cmdline); + ptr = append_rootblock(ptr, fdt_cmdline, len, fdt); + +#else len = strlen(fdt_cmdline); if (ptr - cmdline + len + 2 < COMMAND_LINE_SIZE) { *ptr++ = ' '; memcpy(ptr, fdt_cmdline, len); ptr += len; } +#endif } *ptr = '\0'; @@ -166,7 +251,9 @@ int atags_to_fdt(void *atag_list, void * else setprop_string(fdt, "/chosen", "bootargs", atag->u.cmdline.cmdline); - } else if (atag->hdr.tag == ATAG_MEM) { + } +#ifndef CONFIG_ARM_ATAG_DTB_COMPAT_CMDLINE_MANGLE + else if (atag->hdr.tag == ATAG_MEM) { if (memcount >= sizeof(mem_reg_property)/4) continue; if (!atag->u.mem.size) @@ -210,6 +297,10 @@ int atags_to_fdt(void *atag_list, void * setprop(fdt, "/memory", "reg", mem_reg_property, 4 * memcount * memsize); } +#else + + } +#endif return fdt_pack(fdt); } --- a/init/main.c +++ b/init/main.c @@ -104,6 +104,10 @@ #define CREATE_TRACE_POINTS #include +#if defined(CONFIG_ARM_ATAG_DTB_COMPAT_CMDLINE_MANGLE) +#include +#endif + static int kernel_init(void *); extern void init_IRQ(void); @@ -633,6 +637,18 @@ asmlinkage __visible void __init start_k pr_notice("Kernel command line: %s\n", boot_command_line); /* parameters may set static keys */ jump_label_init(); + +#if defined(CONFIG_ARM_ATAG_DTB_COMPAT_CMDLINE_MANGLE) + //Show bootloader's original command line for reference + if(of_chosen) { + const char *prop = of_get_property(of_chosen, "bootloader-args", NULL); + if(prop) + pr_notice("Bootloader command line (ignored): %s\n", prop); + else + pr_notice("Bootloader command line not present\n"); + } +#endif + parse_early_param(); after_dashes = parse_args("Booting kernel", static_command_line, __start___param,