[U-Boot] [PATCH 3/4] arm64: Non-manual relocation
FengHua
fenghua at phytium.com.cn
Fri Oct 4 18:13:18 CEST 2013
> This turns off CONFIG_NEEDS_MANUAL_RELOC and turns on -pie.
>
> The bss part of the linker script is changed to be more like arm32,
> as the previous arm64 approach was generating bad relocations (even
> readelf didn't like them).
>
> relocate_64.S is made to look more like relocate.S, and then changed to
> support RELA style relocations rather than REL.
>
> Signed-off-by: Scott Wood <scottwood at freescale.com>
> ---
> arch/arm/config.mk | 2 --
> arch/arm/cpu/armv8/config.mk | 1 -
> arch/arm/cpu/armv8/u-boot.lds | 32 +++++++++++++++++++++++-------
> arch/arm/include/asm/config.h | 5 -----
> arch/arm/lib/crt0_64.S | 7 ++-----
> arch/arm/lib/relocate_64.S | 41 ++++++++++++++++++++-------------------
> include/configs/vexpress_aemv8a.h | 3 +++
> 7 files changed, 51 insertions(+), 40 deletions(-)
>
> diff --git a/arch/arm/config.mk b/arch/arm/config.mk
> index 95c07ad..96d2d88 100644
> --- a/arch/arm/config.mk
> +++ b/arch/arm/config.mk
> @@ -74,9 +74,7 @@ endif
> endif
>
> # needed for relocation
> -ifndef CONFIG_ARM64
> LDFLAGS_u-boot += -pie
> -endif
>
> #
> # FIXME: binutils versions < 2.22 have a bug in the assembler where
> diff --git a/arch/arm/cpu/armv8/config.mk b/arch/arm/cpu/armv8/config.mk
> index 9f36d59..027a68c 100644
> --- a/arch/arm/cpu/armv8/config.mk
> +++ b/arch/arm/cpu/armv8/config.mk
> @@ -13,4 +13,3 @@ PLATFORM_NO_UNALIGNED := $(PF_NO_UNALIGNED)
> PF_CPPFLAGS_ARMV8 := $(call cc-option, -march=armv8-a)
> PLATFORM_CPPFLAGS += $(PF_CPPFLAGS_ARMV8)
> PLATFORM_CPPFLAGS += $(PF_NO_UNALIGNED)
> -PLATFORM_CPPFLAGS += -fpic
> diff --git a/arch/arm/cpu/armv8/u-boot.lds b/arch/arm/cpu/armv8/u-boot.lds
> index 328d477..4c12222 100644
> --- a/arch/arm/cpu/armv8/u-boot.lds
> +++ b/arch/arm/cpu/armv8/u-boot.lds
> @@ -41,25 +41,43 @@ SECTIONS
> }
>
> . = ALIGN(8);
> - .reloc : {
> - __rel_got_start = .;
> - *(.got)
> - __rel_got_end = .;
> - }
>
> .image_copy_end :
> {
> *(.__image_copy_end)
> }
>
> + . = ALIGN(8);
> +
> + .rel_dyn_start :
> + {
> + *(.__rel_dyn_start)
> + }
> +
> + .rela.dyn : {
> + *(.rela*)
> + }
> +
> + .rel_dyn_end :
> + {
> + *(.__rel_dyn_end)
> + }
> +
> _end = .;
>
> . = ALIGN(8);
> +
> + .bss_start : {
> + KEEP(*(.__bss_start));
> + }
> +
> .bss : {
> - __bss_start = .;
> *(.bss*)
> . = ALIGN(8);
> - __bss_end = .;
> + }
> +
> + .bss_end : {
> + KEEP(*(.__bss_end));
> }
>
> /DISCARD/ : { *(.dynsym) }
> diff --git a/arch/arm/include/asm/config.h b/arch/arm/include/asm/config.h
> index 0ee131d..de4d01e 100644
> --- a/arch/arm/include/asm/config.h
> +++ b/arch/arm/include/asm/config.h
> @@ -11,11 +11,6 @@
> #define CONFIG_SYS_BOOT_RAMDISK_HIGH
>
> #ifdef CONFIG_ARM64
> -/*
> - * Currently, GOT is used to relocate u-boot and
> - * configuration CONFIG_NEEDS_MANUAL_RELOC is needed.
> - */
> -#define CONFIG_NEEDS_MANUAL_RELOC
> #define CONFIG_PHYS_64BIT
> #endif
>
> diff --git a/arch/arm/lib/crt0_64.S b/arch/arm/lib/crt0_64.S
> index ddd46eb..7756396 100644
> --- a/arch/arm/lib/crt0_64.S
> +++ b/arch/arm/lib/crt0_64.S
> @@ -94,11 +94,8 @@ relocation_return:
> /*
> * Clear BSS section
> */
> - ldr x9, [x18, #GD_RELOC_OFF] /* x9 <- gd->reloc_off */
> - ldr x0, =__bss_start
> - add x0, x0, x9 /* x0 <- __bss_start in RAM */
> - ldr x1, =__bss_end
> - add x1, x1, x9 /* x1 <- __bss_end in RAM */
> + ldr x0, =__bss_start /* this is auto-relocated! */
> + ldr x1, =__bss_end /* this is auto-relocated! */
> mov x2, #0
> clear_loop:
> str x2, [x0]
> diff --git a/arch/arm/lib/relocate_64.S b/arch/arm/lib/relocate_64.S
> index 29c3239..7fba9e2 100644
> --- a/arch/arm/lib/relocate_64.S
> +++ b/arch/arm/lib/relocate_64.S
> @@ -16,40 +16,41 @@
> * void relocate_code (addr_moni)
> *
> * This function relocates the monitor code.
> - *
> - * NOTE:
> - * GOT is used and configuration CONFIG_NEEDS_MANUAL_RELOC is needed.
> + * x0 holds the destination address.
> */
> ENTRY(relocate_code)
> /*
> * Copy u-boot from flash to RAM
> */
> - ldr x1, =__image_copy_start /* x1 <- copy source */
> - cmp x1, x0
> + ldr x1, =__image_copy_start /* x1 <- SRC &__image_copy_start */
> + subs x9, x0, x1 /* x9 <- relocation offset */
> b.eq relocate_done /* skip relocation */
> - mov x2, x0 /* x2 <- copy destination */
> - ldr x3, =__image_copy_end /* x3 <- source end address */
> + ldr x2, =__image_copy_end /* x2 <- SRC &__image_copy_end */
>
> copy_loop:
> ldp x10, x11, [x1], #16 /* copy from source address [x1] */
> - stp x10, x11, [x2], #16 /* copy to target address [x2] */
> - cmp x1, x3 /* until source end address [x3] */
> + stp x10, x11, [x0], #16 /* copy to target address [x0] */
> + cmp x1, x2 /* until source end address [x2] */
> b.lo copy_loop
>
> /*
> - * Fix .reloc relocations
> + * Fix .rela.dyn relocations
> */
> - ldr x9, [x18, #GD_RELOC_OFF]/* x9 <- relocation offset */
> - ldr x1, =__rel_got_start /* x1 <- rel got start ofs */
> - add x1, x1, x9 /* x1 <- rel got start in RAM */
> - ldr x2, =__rel_got_end /* x2 <- rel got end ofs */
> - add x2, x2, x9 /* x2 <- rel got end in RAM */
> + ldr x2, =__rel_dyn_start /* x2 <- SRC &__rel_dyn_start */
> + ldr x3, =__rel_dyn_end /* x3 <- SRC &__rel_dyn_end */
> fixloop:
> - ldr x10, [x1]
> - add x10, x10, x9 /* x10 <- address to be fixed up */
> - str x10, [x1]
> - add x1, x1, #8 /* each got entry is 8 bytes */
> - cmp x1, x2
> + ldp x0, x1, [x2], #16 /* (x0,x1) <- (SRC location, fixup) */
> + ldr x4, [x2], #8 /* x4 <- addend */
> + and x1, x1, #0xffffffff
> + cmp x1, #1027 /* relative fixup? */
> + bne fixnext
> +
> + /* relative fix: store addend plus offset at dest location */
> + add x0, x0, x9
> + add x4, x4, x9
> + str x4, [x0]
> +fixnext:
> + cmp x2, x3
> b.lo fixloop
>
> relocate_done:
> diff --git a/include/configs/vexpress_aemv8a.h b/include/configs/vexpress_aemv8a.h
> index 01c95f5..3932e00 100644
> --- a/include/configs/vexpress_aemv8a.h
> +++ b/include/configs/vexpress_aemv8a.h
> @@ -10,6 +10,9 @@
>
> #define DEBUG
>
> +#define CONFIG_REMAKE_ELF
> +#define CONFIG_STATIC_RELA
> +
CONFIG_STATIC_RELA is always needed, How about remove this macro.
David,
More information about the U-Boot
mailing list