1 From 71270226b14733a4b1f2cde58ea9265caa50b38d Mon Sep 17 00:00:00 2001
2 From: Adrian Panella <ianchi74@outlook.com>
3 Date: Thu, 9 Mar 2017 09:37:17 +0100
4 Subject: [PATCH 67/69] generic: Mangle bootloader's kernel arguments
6 The command-line arguments provided by the boot loader will be
7 appended to a new device tree property: bootloader-args.
8 If there is a property "append-rootblock" in DT under /chosen
9 and a root= option in bootloaders command line it will be parsed
10 and added to DT bootargs with the form: <append-rootblock>XX.
11 Only command line ATAG will be processed, the rest of the ATAGs
12 sent by bootloader will be ignored.
13 This is usefull in dual boot systems, to get the current root partition
14 without afecting the rest of the system.
16 Signed-off-by: Adrian Panella <ianchi74@outlook.com>
18 This patch has been modified to be mvebu specific. The original patch
19 did not pass the bootloader cmdline on if no append-rootblock stanza
20 was found, resulting in blank cmdline and failure to boot.
22 Signed-off-by: Michael Gray <michael.gray@lantisproject.com>
24 arch/arm/Kconfig | 11 ++++
25 arch/arm/boot/compressed/atags_to_fdt.c | 85 ++++++++++++++++++++++++-
26 init/main.c | 16 +++++
27 3 files changed, 111 insertions(+), 1 deletion(-)
29 --- a/arch/arm/Kconfig
30 +++ b/arch/arm/Kconfig
31 @@ -1777,6 +1777,17 @@ config ARM_ATAG_DTB_COMPAT_CMDLINE_EXTEN
32 The command-line arguments provided by the boot loader will be
33 appended to the the device tree bootargs property.
35 +config ARM_ATAG_DTB_COMPAT_CMDLINE_MANGLE
36 + bool "Append rootblock parsing bootloader's kernel arguments"
38 + The command-line arguments provided by the boot loader will be
39 + appended to a new device tree property: bootloader-args.
40 + If there is a property "append-rootblock" in DT under /chosen
41 + and a root= option in bootloaders command line it will be parsed
42 + and added to DT bootargs with the form: <append-rootblock>XX.
43 + Only command line ATAG will be processed, the rest of the ATAGs
44 + sent by bootloader will be ignored.
49 --- a/arch/arm/boot/compressed/atags_to_fdt.c
50 +++ b/arch/arm/boot/compressed/atags_to_fdt.c
53 #if defined(CONFIG_ARM_ATAG_DTB_COMPAT_CMDLINE_EXTEND)
54 #define do_extend_cmdline 1
55 +#elif defined(CONFIG_ARM_ATAG_DTB_COMPAT_CMDLINE_MANGLE)
56 +#define do_extend_cmdline 1
58 #define do_extend_cmdline 0
60 @@ -69,6 +71,72 @@ static uint32_t get_cell_size(const void
64 +#if defined(CONFIG_ARM_ATAG_DTB_COMPAT_CMDLINE_MANGLE)
66 +static char *append_rootblock(char *dest, const char *str, int len, void *fdt)
71 + const char *rootblock;
73 + //ARM doesn't have __HAVE_ARCH_STRSTR, so search manually
77 + //first find an 'r' at the begining or after a space
80 + ptr = strchr(ptr, 'r');
84 + } while (ptr != str && *(ptr-1) != ' ');
86 + //then check for the rest
87 + for(i = 1; i <= 4; i++)
88 + if(*(ptr+i) != *(root+i)) break;
92 + end = strchr(ptr, ' ');
93 + end = end ? (end - 1) : (strchr(ptr, 0) - 1);
95 + //find partition number (assumes format root=/dev/mtdXX | /dev/mtdblockXX | yy:XX )
96 + for( i = 0; end >= ptr && *end >= '0' && *end <= '9'; end--, i++);
99 + /* if append-rootblock property is set use it to append to command line */
100 + rootblock = getprop(fdt, "/chosen", "append-rootblock", &l);
101 + if (rootblock == NULL)
104 + if (*dest != ' ') {
110 + if (len + l + i <= COMMAND_LINE_SIZE) {
111 + memcpy(dest, rootblock, l);
113 + memcpy(dest, ptr, i);
121 + if (len + 1 < COMMAND_LINE_SIZE) {
122 + memcpy(dest, str, len);
130 static void merge_fdt_bootargs(void *fdt, const char *fdt_cmdline)
132 char cmdline[COMMAND_LINE_SIZE];
133 @@ -88,12 +156,21 @@ static void merge_fdt_bootargs(void *fdt
135 /* and append the ATAG_CMDLINE */
138 +#if defined(CONFIG_ARM_ATAG_DTB_COMPAT_CMDLINE_MANGLE)
139 + //save original bootloader args
140 + //and append ubi.mtd with root partition number to current cmdline
141 + setprop_string(fdt, "/chosen", "bootloader-args", fdt_cmdline);
142 + ptr = append_rootblock(ptr, fdt_cmdline, len, fdt);
145 len = strlen(fdt_cmdline);
146 if (ptr - cmdline + len + 2 < COMMAND_LINE_SIZE) {
148 memcpy(ptr, fdt_cmdline, len);
155 @@ -168,7 +245,9 @@ int atags_to_fdt(void *atag_list, void *
157 setprop_string(fdt, "/chosen", "bootargs",
158 atag->u.cmdline.cmdline);
159 - } else if (atag->hdr.tag == ATAG_MEM) {
161 +#ifndef CONFIG_ARM_ATAG_DTB_COMPAT_CMDLINE_MANGLE
162 + else if (atag->hdr.tag == ATAG_MEM) {
163 if (memcount >= sizeof(mem_reg_property)/4)
165 if (!atag->u.mem.size)
166 @@ -212,6 +291,10 @@ int atags_to_fdt(void *atag_list, void *
167 setprop(fdt, "/memory", "reg", mem_reg_property,
168 4 * memcount * memsize);
175 return fdt_pack(fdt);
181 #include <kunit/test.h>
183 +#if defined(CONFIG_ARM_ATAG_DTB_COMPAT_CMDLINE_MANGLE)
184 +#include <linux/of.h>
187 static int kernel_init(void *);
189 extern void init_IRQ(void);
190 @@ -904,6 +908,18 @@ asmlinkage __visible void __init __no_sa
193 pr_notice("Kernel command line: %s\n", saved_command_line);
195 +#if defined(CONFIG_ARM_ATAG_DTB_COMPAT_CMDLINE_MANGLE)
196 + //Show bootloader's original command line for reference
198 + const char *prop = of_get_property(of_chosen, "bootloader-args", NULL);
200 + pr_notice("Bootloader command line (ignored): %s\n", prop);
202 + pr_notice("Bootloader command line not present\n");
206 /* parameters may set static keys */