[PATCH 6/6] ARM: Add relocatable binary support
Alexander Aring
alex.aring at gmail.com
Mon Mar 4 15:53:22 EST 2013
Hi,
On Mon, Mar 04, 2013 at 09:03:09PM +0100, Sascha Hauer wrote:
> For making the same binary executable on different SoCs which have
> different DRAM addresses we have to be independent of the compile
> time link address.
>
> This patch adds relocatable binary support for the ARM architecture.
> With this two new functions are available. relocate_to_current_adr
> will fixup the binary to continue executing from the current position.
> relocate_to_adr will copy the binary to a given address, fixup the
> binary and continue executing from there.
>
> For the PBL and the real image relocatable support can be enabled
> independently. This is done to (hopefully) better cope with setups
> where the PBL runs from SRAM or ROM and the real binary does not.
>
> Signed-off-by: Sascha Hauer <s.hauer at pengutronix.de>
> ---
> arch/arm/Kconfig | 9 +++++
> arch/arm/Makefile | 4 +++
> arch/arm/cpu/Makefile | 3 ++
> arch/arm/cpu/common.c | 68 ++++++++++++++++++++++++++++++++++++++
> arch/arm/cpu/setupc.S | 59 +++++++++++++++++++++++++++++++++
> arch/arm/cpu/start-pbl.c | 18 +++++++---
> arch/arm/cpu/start.c | 5 +++
> arch/arm/include/asm/barebox-arm.h | 26 +++++++++++++++
> arch/arm/lib/barebox.lds.S | 17 ++++++++++
> arch/arm/pbl/Makefile | 3 ++
> arch/arm/pbl/zbarebox.lds.S | 16 +++++++++
> common/Kconfig | 2 +-
> pbl/Kconfig | 10 ++++++
> 13 files changed, 235 insertions(+), 5 deletions(-)
> create mode 100644 arch/arm/cpu/common.c
>
> diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
> index 7ac134e..efe0773 100644
> --- a/arch/arm/Kconfig
> +++ b/arch/arm/Kconfig
> @@ -12,6 +12,15 @@ config ARM_LINUX
> default y
> depends on CMD_BOOTZ || CMD_BOOTU || CMD_BOOTM
>
> +config RELOCATABLE
> + prompt "relocatable binary"
> + bool
> + help
> + Generate a binary which can relocate itself during startup to run
> + on different addresses. This is useful if your memory layout is not
> + known during compile time. Selecting this will result in a slightly
> + bigger image.
> +
> config HAVE_MACH_ARM_HEAD
> bool
>
> diff --git a/arch/arm/Makefile b/arch/arm/Makefile
> index b98d6b8..5125b87 100644
> --- a/arch/arm/Makefile
> +++ b/arch/arm/Makefile
> @@ -181,6 +181,10 @@ CPPFLAGS += -fdata-sections -ffunction-sections
> LDFLAGS_barebox += -static --gc-sections
> endif
>
> +ifdef CONFIG_RELOCATABLE
> +LDFLAGS_barebox += -pie
> +endif
> +
> ifdef CONFIG_IMAGE_COMPRESSION
> KBUILD_BINARY := arch/arm/pbl/zbarebox.bin
> KBUILD_TARGET := zbarebox.bin
> diff --git a/arch/arm/cpu/Makefile b/arch/arm/cpu/Makefile
> index 44410ee..5935e1c 100644
> --- a/arch/arm/cpu/Makefile
> +++ b/arch/arm/cpu/Makefile
> @@ -21,3 +21,6 @@ pbl-$(CONFIG_CPU_32v7) += cache-armv7.o
> obj-$(CONFIG_CACHE_L2X0) += cache-l2x0.o
>
> pbl-y += start-pbl.o setupc.o
> +
> +obj-y += common.o
> +pbl-y += common.o
> diff --git a/arch/arm/cpu/common.c b/arch/arm/cpu/common.c
> new file mode 100644
> index 0000000..856ddf2
> --- /dev/null
> +++ b/arch/arm/cpu/common.c
> @@ -0,0 +1,68 @@
> +/*
> + * Copyright (c) 2010 Sascha Hauer <s.hauer at pengutronix.de>, Pengutronix
> + *
> + * See file CREDITS for list of people who contributed to this
> + * project.
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2
> + * as published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> + * GNU General Public License for more details.
> + *
> + */
> +
> +#include <common.h>
> +#include <init.h>
> +#include <sizes.h>
> +#include <asm/barebox-arm.h>
> +#include <asm/barebox-arm-head.h>
> +#include <asm-generic/memory_layout.h>
> +#include <asm/sections.h>
> +#include <asm/pgtable.h>
> +#include <asm/cache.h>
> +
> +/*
> + * relocate binary to the currently running address
> + */
> +void relocate_to_current_adr(void)
> +{
> + uint32_t offset;
> + uint32_t *dstart, *dend, *dynsym;
> + uint32_t *dynend;
Some nitpick... we can do this in one line maybe with fixup and type.
> +
> + /* Get offset between linked address and runtime address */
> + offset = get_runtime_offset();
> +
> + dstart = (void *)(ld_var(__rel_dyn_start) - offset);
> + dend = (void *)(ld_var(__rel_dyn_end) - offset);
> +
> + dynsym = (void *)(ld_var(__dynsym_start) - offset);
> + dynend = (void *)(ld_var(__dynsym_end) - offset);
> +
> + while (dstart < dend) {
> + uint32_t *fixup = (uint32_t *)(*dstart - offset);
> + uint32_t type = *(dstart + 1);
> +
> + if ((type & 0xff) == 0x17) {
> + *fixup = *fixup - offset;
> + } else {
> + int index = type >> 8;
> + uint32_t r = dynsym[index * 4 + 1];
> +
> + *fixup = *fixup + r - offset;
> + }
> +
> + *dstart -= offset;
> + dstart += 2;
> + }
> +
> + while (dynsym < dynend)
> + *dynsym++ = 0;
I think here we can use a memset. :-)
> +
> + arm_early_mmu_cache_flush();
> + flush_icache();
> +}
> diff --git a/arch/arm/cpu/setupc.S b/arch/arm/cpu/setupc.S
> index d0de87d..7fd5d01 100644
> --- a/arch/arm/cpu/setupc.S
> +++ b/arch/arm/cpu/setupc.S
> @@ -1,4 +1,5 @@
> #include <linux/linkage.h>
> +#include <asm/sections.h>
>
> .section .text.setupc
>
> @@ -35,3 +36,61 @@ ENTRY(setup_c)
> pop {r4, r5}
> mov pc, lr
> ENDPROC(setup_c)
> +
> +#ifdef CONFIG_RELOCATABLE
> +/*
> + * void relocate_to_adr(unsigned long targetadr)
> + *
> + * Copy binary to targetadr, relocate code, clear bss and continue
> + * executing at new address.
> + */
> +.section .text.relocate_to_adr
> +ENTRY(relocate_to_adr)
> + /* r0: target address */
> + push {r3, r4, r5, r6, r7, r8}
> + mov r7, lr
> +
> + mov r6, r0
> +
> + bl get_runtime_offset
> +
> + mov r5, r0
> +
> + ld_var _text, r0, r4
> + mov r8, r0
> +
> + sub r1, r0, r5 /* r1: from address */
> +
> + cmp r1, r6 /* already at correct address? */
> + beq 1f /* yes, skip copy to new address */
> +
> + ld_var __bss_start, r2, r4
> +
> + sub r2, r2, r0 /* r2: size */
> + mov r0, r6 /* r0: target */
> +
> + add r7, r7, r0 /* adjust return address */
> + sub r7, r7, r1 /* lr += offset */
> +
> + bl memcpy /* copy binary */
> +
> +#ifdef CONFIG_MMU
> + bl arm_early_mmu_cache_flush
> +#endif
> + mov r0,#0
> + mcr p15, 0, r0, c7, c5, 0 /* flush icache */
> +
> + ldr r0,=1f
> + sub r0, r0, r8
> + add r0, r0, r6
> + mov pc, r0 /* jump to relocated address */
> +1:
Is this label ever used? I don't see it.
> + bl relocate_to_current_adr /* relocate binary */
> +
> + mov lr, r7
> +
> + pop {r3, r4, r5, r6, r7, r8}
> + mov pc, lr
> +
> +ENDPROC(relocate_to_adr)
> +#endif
> diff --git a/arch/arm/cpu/start-pbl.c b/arch/arm/cpu/start-pbl.c
> index 91bc8fe..6f03c4a 100644
> --- a/arch/arm/cpu/start-pbl.c
> +++ b/arch/arm/cpu/start-pbl.c
> @@ -55,9 +55,13 @@ static noinline __noreturn void __barebox_arm_entry(uint32_t membase,
> uint32_t pg_start, pg_end, pg_len;
> void __noreturn (*barebox)(uint32_t, uint32_t, uint32_t);
> uint32_t endmem = membase + memsize;
> + unsigned long barebox_base;
>
> endmem -= STACK_SIZE; /* stack */
>
> + if (IS_ENABLED(CONFIG_PBL_RELOCATABLE))
> + relocate_to_current_adr();
> +
> /* Get offset between linked address and runtime address */
> offset = get_runtime_offset();
>
> @@ -65,8 +69,13 @@ static noinline __noreturn void __barebox_arm_entry(uint32_t membase,
> pg_end = (uint32_t)&input_data_end - offset;
> pg_len = pg_end - pg_start;
>
> + if (IS_ENABLED(CONFIG_RELOCATABLE))
> + barebox_base = arm_barebox_image_place(membase + memsize);
> + else
> + barebox_base = TEXT_BASE;
> +
> if (offset && (IS_ENABLED(CONFIG_PBL_FORCE_PIGGYDATA_COPY) ||
> - region_overlap(pg_start, pg_len, TEXT_BASE, pg_len * 4))) {
> + region_overlap(pg_start, pg_len, barebox_base, pg_len * 4))) {
> /*
> * copy piggydata binary to its link address
> */
> @@ -86,14 +95,15 @@ static noinline __noreturn void __barebox_arm_entry(uint32_t membase,
> free_mem_ptr = endmem;
> free_mem_end_ptr = free_mem_ptr + SZ_128K;
>
> - pbl_barebox_uncompress((void*)TEXT_BASE, (void *)pg_start, pg_len);
> + pbl_barebox_uncompress((void*)barebox_base, (void *)pg_start, pg_len);
>
> + arm_early_mmu_cache_flush();
> flush_icache();
>
> if (IS_ENABLED(CONFIG_THUMB2_BAREBOX))
> - barebox = (void *)(TEXT_BASE + 1);
> + barebox = (void *)(barebox_base + 1);
> else
> - barebox = (void *)TEXT_BASE;
> + barebox = (void *)barebox_base;
>
> barebox(membase, memsize, boarddata);
> }
> diff --git a/arch/arm/cpu/start.c b/arch/arm/cpu/start.c
> index cd34d9c..7c2bcd0 100644
> --- a/arch/arm/cpu/start.c
> +++ b/arch/arm/cpu/start.c
> @@ -37,6 +37,11 @@ static noinline __noreturn void __start(uint32_t membase, uint32_t memsize,
> unsigned long endmem = membase + memsize;
> unsigned long malloc_start, malloc_end;
>
> + if (IS_ENABLED(CONFIG_RELOCATABLE)) {
> + unsigned long barebox_base = arm_barebox_image_place(endmem);
> + relocate_to_adr(barebox_base);
> + }
> +
> setup_c();
>
> arm_stack_top = endmem;
> diff --git a/arch/arm/include/asm/barebox-arm.h b/arch/arm/include/asm/barebox-arm.h
> index f051fe3..76e31a0 100644
> --- a/arch/arm/include/asm/barebox-arm.h
> +++ b/arch/arm/include/asm/barebox-arm.h
> @@ -26,6 +26,7 @@
> #define _BAREBOX_ARM_H_
>
> #include <sizes.h>
> +#include <asm-generic/memory_layout.h>
>
> /* cpu/.../cpu.c */
> int cleanup_before_linux(void);
> @@ -40,6 +41,8 @@ void board_init_lowlevel(void);
> uint32_t get_runtime_offset(void);
>
> void setup_c(void);
> +void relocate_to_current_adr(void);
> +void relocate_to_adr(unsigned long target);
> void __noreturn barebox_arm_entry(uint32_t membase, uint32_t memsize, uint32_t boarddata);
>
> #ifdef CONFIG_RELOCATABLE
> @@ -50,4 +53,27 @@ static inline void arm_fixup_vectors(void)
> }
> #endif
>
> +/*
> + * For relocatable binaries find a suitable start address for the
> + * relocated binary. Beginning at the memory end substract the reserved
> + * space and round down a bit at the end. This is used by the pbl to
> + * extract the image to a suitable place so that the uncompressed image
> + * does not have to copy itself to another place. Also it's used by
> + * the uncompressed image to relocate itself to the same place.
> + */
> +static inline unsigned long arm_barebox_image_place(unsigned long endmem)
> +{
> + endmem -= STACK_SIZE;
> + endmem -= SZ_32K; /* ttb */
> + endmem -= SZ_128K; /* early malloc */
> + endmem -= SZ_1M; /* place for barebox image */
> +
> + /*
> + * round down to make translating the objdump easier
> + */
> + endmem &= ~(SZ_1M - 1);
> +
> + return endmem;
> +}
> +
> #endif /* _BAREBOX_ARM_H_ */
> diff --git a/arch/arm/lib/barebox.lds.S b/arch/arm/lib/barebox.lds.S
> index e5aee8c..abdd69e 100644
> --- a/arch/arm/lib/barebox.lds.S
> +++ b/arch/arm/lib/barebox.lds.S
> @@ -25,7 +25,11 @@ OUTPUT_ARCH(arm)
> ENTRY(start)
> SECTIONS
> {
> +#ifdef CONFIG_RELOCATABLE
> + . = 0x0;
> +#else
> . = TEXT_BASE;
> +#endif
>
> #ifndef CONFIG_PBL_IMAGE
> PRE_IMAGE
> @@ -88,7 +92,20 @@ SECTIONS
> __usymtab : { BAREBOX_SYMS }
> __usymtab_end = .;
>
> + .rel.dyn : {
> + __rel_dyn_start = .;
> + *(.rel*)
> + __rel_dyn_end = .;
> + }
> +
> + .dynsym : {
> + __dynsym_start = .;
> + *(.dynsym)
> + __dynsym_end = .;
> + }
> +
> _edata = .;
> +
> . = ALIGN(4);
> __bss_start = .;
> .bss : { *(.bss*) }
> diff --git a/arch/arm/pbl/Makefile b/arch/arm/pbl/Makefile
> index 6eeee73..3f50f77 100644
> --- a/arch/arm/pbl/Makefile
> +++ b/arch/arm/pbl/Makefile
> @@ -23,6 +23,9 @@ $(obj)/zbarebox.S: $(obj)/zbarebox FORCE
> PBL_CPPFLAGS += -fdata-sections -ffunction-sections
> LDFLAGS_zbarebox := -Map $(obj)/zbarebox.map
> LDFLAGS_zbarebox += -static --gc-sections
> +ifdef CONFIG_PBL_RELOCATABLE
> +LDFLAGS_zbarebox += -pie
> +endif
> zbarebox-common := $(barebox-pbl-common) $(obj)/$(piggy_o)
> zbarebox-lds := $(obj)/zbarebox.lds
>
> diff --git a/arch/arm/pbl/zbarebox.lds.S b/arch/arm/pbl/zbarebox.lds.S
> index 564b3c6..6b23bbe 100644
> --- a/arch/arm/pbl/zbarebox.lds.S
> +++ b/arch/arm/pbl/zbarebox.lds.S
> @@ -29,7 +29,11 @@ OUTPUT_ARCH(arm)
> ENTRY(pbl_start)
> SECTIONS
> {
> +#ifdef CONFIG_PBL_RELOCATABLE
> + . = 0x0;
> +#else
> . = TEXT_BASE - SZ_2M;
> +#endif
>
> PRE_IMAGE
>
> @@ -58,6 +62,18 @@ SECTIONS
> . = ALIGN(4);
> .data : { *(.data*) }
>
> + .rel.dyn : {
> + __rel_dyn_start = .;
> + *(.rel*)
> + __rel_dyn_end = .;
> + }
> +
> + .dynsym : {
> + __dynsym_start = .;
> + *(.dynsym)
> + __dynsym_end = .;
> + }
> +
> . = ALIGN(4);
> __bss_start = .;
> .bss : { *(.bss*) }
> diff --git a/common/Kconfig b/common/Kconfig
> index 3a55e01..92a6fdf 100644
> --- a/common/Kconfig
> +++ b/common/Kconfig
> @@ -243,7 +243,7 @@ config KALLSYMS
> This is useful to print a nice backtrace when an exception occurs.
>
> config RELOCATABLE
> - depends on PPC
> + depends on PPC || ARM
> bool "generate relocatable barebox binary"
> help
> A non relocatable barebox binary will run at it's compiled in
> diff --git a/pbl/Kconfig b/pbl/Kconfig
> index 39752cc..5c7f62e 100644
> --- a/pbl/Kconfig
> +++ b/pbl/Kconfig
> @@ -18,6 +18,16 @@ config PBL_FORCE_PIGGYDATA_COPY
>
> if PBL_IMAGE
>
> +config PBL_RELOCATABLE
> + depends on ARM
> + bool "relocatable pbl image"
> + help
> + Generate a pbl binary which can relocate itself during startup to run
> + on different addresses. This is useful if your memory layout is not
> + known during compile time.
> + This option only inflluences the PBL image. See RELOCATABLE to also make
> + the real image relocatable.
> +
> config IMAGE_COMPRESSION
> bool
> depends on HAVE_IMAGE_COMPRESSION
> --
> 1.8.2.rc2
>
>
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