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- From bb0c3b0175240bf152fd7c644821a0cf9f77c37c Mon Sep 17 00:00:00 2001
- From: Evgeniy Didin <[email protected]>
- Date: Fri, 15 Mar 2019 18:53:38 +0300
- Subject: [PATCH] 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 <[email protected]>
- Signed-off-by: Alexey Brodkin <[email protected]>
- Signed-off-by: Evgeniy Didin <[email protected]>
- ---
- 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(-)
- --- 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
-
- ;----------------------------------------------------------------
- --- a/arch/arc/kernel/setup.c
- +++ b/arch/arc/kernel/setup.c
- @@ -450,6 +450,8 @@ static inline bool uboot_arg_invalid(uns
- /* 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;
- @@ -488,7 +490,7 @@ 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");
- }
- --- 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)
|
