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
|
From ec54842bfce8240815a9ce7a1db0935851fe9ea8 Mon Sep 17 00:00:00 2001
From: Evgeniy Didin <Evgeniy.Didin@synopsys.com>
Date: Fri, 15 Mar 2019 18:53:38 +0300
Subject: [PATCH 42/96] arc add OWRTDTB section
This change allows OpenWRT to patch resulting kernel binary with
external .dtb.
That allows us to re-use exactky the same vmlinux on different boards
given its ARC core configurations match (at least cache line sizes etc).
""patch-dtb" searches for ASCII "OWRTDTB:" strign and copies external
.dtb right after it, keeping the string in place.
Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
Signed-off-by: Alexey Brodkin <abrodkin@synopsys.com>
Signed-off-by: Evgeniy Didin <Evgeniy.Didin@synopsys.com>
---
arch/arc/kernel/head.S | 10 ++++++++++
arch/arc/kernel/setup.c | 4 +++-
arch/arc/kernel/vmlinux.lds.S | 13 +++++++++++++
3 files changed, 26 insertions(+), 1 deletion(-)
diff --git a/arch/arc/kernel/head.S b/arch/arc/kernel/head.S
index 9152782444b5..167d81ce6ab7 100644
--- a/arch/arc/kernel/head.S
+++ b/arch/arc/kernel/head.S
@@ -88,6 +88,16 @@
DSP_EARLY_INIT
.endm
+ ; Here "patch-dtb" will embed external .dtb
+ ; Note "patch-dtb" searches for ASCII "OWRTDTB:" string
+ ; and pastes .dtb right after it, hense the string precedes
+ ; __image_dtb symbol.
+ .section .owrt, "aw",@progbits
+ .ascii "OWRTDTB:"
+ENTRY(__image_dtb)
+ .fill 0x4000
+END(__image_dtb)
+
.section .init.text, "ax",@progbits
;----------------------------------------------------------------
diff --git a/arch/arc/kernel/setup.c b/arch/arc/kernel/setup.c
index 41f07b3e594e..d0c3e7817022 100644
--- a/arch/arc/kernel/setup.c
+++ b/arch/arc/kernel/setup.c
@@ -495,6 +495,8 @@ static inline bool uboot_arg_invalid(unsigned long addr)
/* We always pass 0 as magic from U-boot */
#define UBOOT_MAGIC_VALUE 0
+extern struct boot_param_header __image_dtb;
+
void __init handle_uboot_args(void)
{
bool use_embedded_dtb = true;
@@ -533,7 +535,7 @@ void __init handle_uboot_args(void)
ignore_uboot_args:
if (use_embedded_dtb) {
- machine_desc = setup_machine_fdt(__dtb_start);
+ machine_desc = setup_machine_fdt(&__image_dtb);
if (!machine_desc)
panic("Embedded DT invalid\n");
}
diff --git a/arch/arc/kernel/vmlinux.lds.S b/arch/arc/kernel/vmlinux.lds.S
index 529ae50f9fe2..ecdcd6842c0d 100644
--- a/arch/arc/kernel/vmlinux.lds.S
+++ b/arch/arc/kernel/vmlinux.lds.S
@@ -27,6 +27,19 @@ SECTIONS
. = CONFIG_LINUX_LINK_BASE;
+ /*
+ * In OpenWRT we want to patch built binary embedding .dtb of choice.
+ * This is implemented with "patch-dtb" utility which searches for
+ * "OWRTDTB:" string in first 16k of image and if it is found
+ * copies .dtb right after mentioned string.
+ *
+ * Note: "OWRTDTB:" won't be overwritten with .dtb, .dtb will follow it.
+ */
+ .owrt : {
+ *(.owrt)
+ . = ALIGN(PAGE_SIZE);
+ }
+
_int_vec_base_lds = .;
.vector : {
*(.vector)
--
2.37.2
|
