--- /dev/null
+From 13bb6d8dd9138927950a520a288401db82871dc9 Mon Sep 17 00:00:00 2001
+From: Christian Marangi <ansuelsmth@gmail.com>
+Date: Sun, 21 Jan 2024 23:36:57 +0100
+Subject: [PATCH] ARM: decompressor: support for ATAGs rootblock parsing
+
+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: <append-rootblock>XX.
+
+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 <ianchi74@outlook.com>
+[ reworked to a cleaner patch ]
+Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
+---
+ arch/arm/Kconfig | 10 +++
+ arch/arm/boot/compressed/atags_to_fdt.c | 102 ++++++++++++++++++++++--
+ init/main.c | 12 +++
+ 3 files changed, 117 insertions(+), 7 deletions(-)
+
+--- a/arch/arm/Kconfig
++++ b/arch/arm/Kconfig
+@@ -1599,6 +1599,16 @@ 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: <append-rootblock>XX.
++
+ endchoice
+
+ config CMDLINE_OVERRIDE
+--- a/arch/arm/boot/compressed/atags_to_fdt.c
++++ b/arch/arm/boot/compressed/atags_to_fdt.c
+@@ -3,7 +3,8 @@
+ #include <asm/setup.h>
+ #include <libfdt.h>
+
+-#if defined(CONFIG_ARM_ATAG_DTB_COMPAT_CMDLINE_EXTEND)
++#if defined(CONFIG_ARM_ATAG_DTB_COMPAT_CMDLINE_EXTEND) || \
++ defined(CONFIG_ARM_ATAG_DTB_COMPAT_CMDLINE_MANGLE)
+ #define do_extend_cmdline 1
+ #else
+ #define do_extend_cmdline 0
+@@ -69,6 +70,83 @@ static uint32_t get_cell_size(const void
+ return cell_size;
+ }
+
++/**
++ * 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;
++ const char *root="root=";
++ const 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;
++}
++
+ static void merge_fdt_bootargs(void *fdt, const char *fdt_cmdline)
+ {
+ char cmdline[COMMAND_LINE_SIZE];
+@@ -86,13 +164,23 @@ static void merge_fdt_bootargs(void *fdt
+ ptr += len - 1;
+ }
+
+- /* and append the ATAG_CMDLINE */
+ if (fdt_cmdline) {
+- len = strlen(fdt_cmdline);
+- if (ptr - cmdline + len + 2 < COMMAND_LINE_SIZE) {
+- *ptr++ = ' ';
+- memcpy(ptr, fdt_cmdline, len);
+- ptr += len;
++ if (IS_ENABLED(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 {
++ /* and append the ATAG_CMDLINE */
++ len = strlen(fdt_cmdline);
++ if (ptr - cmdline + len + 2 < COMMAND_LINE_SIZE) {
++ *ptr++ = ' ';
++ memcpy(ptr, fdt_cmdline, len);
++ ptr += len;
++ }
+ }
+ }
+ *ptr = '\0';
+--- a/init/main.c
++++ b/init/main.c
+@@ -28,6 +28,7 @@
+ #include <linux/initrd.h>
+ #include <linux/memblock.h>
+ #include <linux/acpi.h>
++#include <linux/of.h>
+ #include <linux/bootconfig.h>
+ #include <linux/console.h>
+ #include <linux/nmi.h>
+@@ -995,6 +996,17 @@ asmlinkage __visible void __init __no_sa
+ pr_notice("Kernel command line: %s\n", saved_command_line);
+ /* parameters may set static keys */
+ jump_label_init();
++
++ /* Show bootloader's original command line for reference */
++ if (IS_ENABLED(CONFIG_ARM_ATAG_DTB_COMPAT_CMDLINE_MANGLE) && 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");
++ }
++
+ parse_early_param();
+ after_dashes = parse_args("Booting kernel",
+ static_command_line, __start___param,
projects / openwrt / staging / ansuel.git / blobdiff