1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
|
From 71270226b14733a4b1f2cde58ea9265caa50b38d Mon Sep 17 00:00:00 2001
From: Adrian Panella <ianchi74@outlook.com>
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: <append-rootblock>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 <ianchi74@outlook.com>
---
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
@@ -1780,6 +1780,17 @@ 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: <append-rootblock>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
@@ -5,6 +5,8 @@
#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
@@ -69,6 +71,80 @@ 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];
@@ -88,12 +164,21 @@ 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';
@@ -168,7 +253,9 @@ 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)
@@ -212,6 +299,10 @@ 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
@@ -110,6 +110,10 @@
#include <kunit/test.h>
+#if defined(CONFIG_ARM_ATAG_DTB_COMPAT_CMDLINE_MANGLE)
+#include <linux/of.h>
+#endif
+
static int kernel_init(void *);
extern void init_IRQ(void);
@@ -905,6 +909,18 @@ asmlinkage __visible void __init __no_sa
pr_notice("Kernel command line: %s\n", saved_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,
|
