diff options
Diffstat (limited to 'nixos/modules/kernel-patches/0042-arc-add-OWRTDTB-section.patch')
| -rw-r--r-- | nixos/modules/kernel-patches/0042-arc-add-OWRTDTB-section.patch | 93 |
1 files changed, 93 insertions, 0 deletions
diff --git a/nixos/modules/kernel-patches/0042-arc-add-OWRTDTB-section.patch b/nixos/modules/kernel-patches/0042-arc-add-OWRTDTB-section.patch new file mode 100644 index 0000000..402ea47 --- /dev/null +++ b/nixos/modules/kernel-patches/0042-arc-add-OWRTDTB-section.patch @@ -0,0 +1,93 @@ +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 + |