| developer | f11ee16 | 2022-04-12 11:17:45 +0800 | [diff] [blame] | 1 | From bb0c3b0175240bf152fd7c644821a0cf9f77c37c Mon Sep 17 00:00:00 2001 |
| 2 | From: Evgeniy Didin <Evgeniy.Didin@synopsys.com> |
| 3 | Date: Fri, 15 Mar 2019 18:53:38 +0300 |
| 4 | Subject: [PATCH] arc add OWRTDTB section |
| 5 | |
| 6 | This change allows OpenWRT to patch resulting kernel binary with |
| 7 | external .dtb. |
| 8 | |
| 9 | That allows us to re-use exactky the same vmlinux on different boards |
| 10 | given its ARC core configurations match (at least cache line sizes etc). |
| 11 | |
| 12 | ""patch-dtb" searches for ASCII "OWRTDTB:" strign and copies external |
| 13 | .dtb right after it, keeping the string in place. |
| 14 | |
| 15 | Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com> |
| 16 | Signed-off-by: Alexey Brodkin <abrodkin@synopsys.com> |
| 17 | Signed-off-by: Evgeniy Didin <Evgeniy.Didin@synopsys.com> |
| 18 | --- |
| 19 | arch/arc/kernel/head.S | 10 ++++++++++ |
| 20 | arch/arc/kernel/setup.c | 4 +++- |
| 21 | arch/arc/kernel/vmlinux.lds.S | 13 +++++++++++++ |
| 22 | 3 files changed, 26 insertions(+), 1 deletion(-) |
| 23 | |
| 24 | --- a/arch/arc/kernel/head.S |
| 25 | +++ b/arch/arc/kernel/head.S |
| 26 | @@ -61,6 +61,16 @@ |
| 27 | #endif |
| 28 | .endm |
| 29 | |
| 30 | + ; Here "patch-dtb" will embed external .dtb |
| 31 | + ; Note "patch-dtb" searches for ASCII "OWRTDTB:" string |
| 32 | + ; and pastes .dtb right after it, hense the string precedes |
| 33 | + ; __image_dtb symbol. |
| 34 | + .section .owrt, "aw",@progbits |
| 35 | + .ascii "OWRTDTB:" |
| 36 | +ENTRY(__image_dtb) |
| 37 | + .fill 0x4000 |
| 38 | +END(__image_dtb) |
| 39 | + |
| 40 | .section .init.text, "ax",@progbits |
| 41 | |
| 42 | ;---------------------------------------------------------------- |
| 43 | --- a/arch/arc/kernel/setup.c |
| 44 | +++ b/arch/arc/kernel/setup.c |
| 45 | @@ -492,6 +492,8 @@ static inline bool uboot_arg_invalid(uns |
| 46 | /* We always pass 0 as magic from U-boot */ |
| 47 | #define UBOOT_MAGIC_VALUE 0 |
| 48 | |
| 49 | +extern struct boot_param_header __image_dtb; |
| 50 | + |
| 51 | void __init handle_uboot_args(void) |
| 52 | { |
| 53 | bool use_embedded_dtb = true; |
| 54 | @@ -530,7 +532,7 @@ void __init handle_uboot_args(void) |
| 55 | ignore_uboot_args: |
| 56 | |
| 57 | if (use_embedded_dtb) { |
| 58 | - machine_desc = setup_machine_fdt(__dtb_start); |
| 59 | + machine_desc = setup_machine_fdt(&__image_dtb); |
| 60 | if (!machine_desc) |
| 61 | panic("Embedded DT invalid\n"); |
| 62 | } |
| 63 | --- a/arch/arc/kernel/vmlinux.lds.S |
| 64 | +++ b/arch/arc/kernel/vmlinux.lds.S |
| 65 | @@ -27,6 +27,19 @@ SECTIONS |
| 66 | |
| 67 | . = CONFIG_LINUX_LINK_BASE; |
| 68 | |
| 69 | + /* |
| 70 | + * In OpenWRT we want to patch built binary embedding .dtb of choice. |
| 71 | + * This is implemented with "patch-dtb" utility which searches for |
| 72 | + * "OWRTDTB:" string in first 16k of image and if it is found |
| 73 | + * copies .dtb right after mentioned string. |
| 74 | + * |
| 75 | + * Note: "OWRTDTB:" won't be overwritten with .dtb, .dtb will follow it. |
| 76 | + */ |
| 77 | + .owrt : { |
| 78 | + *(.owrt) |
| 79 | + . = ALIGN(PAGE_SIZE); |
| 80 | + } |
| 81 | + |
| 82 | _int_vec_base_lds = .; |
| 83 | .vector : { |
| 84 | *(.vector) |