openwrt/target/linux/generic/pending-5.10/332-arc-add-OWRTDTB-section.patch
Olliver Schinagl d5bf46bbe8
generic: Convert incorrect generic/5.10 patches
OpenWRT's developer guide prefers having actual patches so they an be
sent upstream more easily.

However, in this case, Adding proper fields also allows for `git am` to
properly function. Some of these patches are quite old, and lack much
traceable history.

This commit tries to rectify that, by digging in the history to find
where and how it was first added.

It is by no means perfect and also shows some patches that should have
been long gone.

Signed-off-by: Olliver Schinagl <oliver@schinagl.nl>
2022-10-01 02:47:56 +02:00

85 lines
2.5 KiB
Diff

From bb0c3b0175240bf152fd7c644821a0cf9f77c37c 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] 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(-)
--- 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
@@ -495,6 +495,8 @@ 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;
@@ -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");
}
--- 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)