[PATCH] ARM: move exception vectors away from start of binary
Jean-Christophe PLAGNIOL-VILLARD
plagnioj at jcrosoft.com
Thu Jan 5 08:17:12 EST 2012
On 10:23 Thu 05 Jan , Sascha Hauer wrote:
> Traditionally U-Boot and barebox have the exception vectors at
> the start of the binary. There is no real reason in doing so,
> because in the majority of cases this data will not be at 0x0
> where it could be used as vectors directly anyway.
> This patch puts the vectors into a separate linker section and
> defines an head function which is placed at the start of the
> image instead. Putting this in a separate function also has
> the advantage that it can be placed at the start of images
> which require an additional header like several Freescale i.MX
> images. As the head function contains the barebox arm magic
> those images can now also be detected as barebox images.
> The header of the image can be customized using
> CONFIG_ARM_CUSTOM_HEAD. If this is set the user must specify
> a custom barebox_arm_head function in the text_entry section.
>
> Signed-off-by: Sascha Hauer <s.hauer at pengutronix.de>
> ---
Please hold on this one
As I said I work on at91 boot let me check it work before apply this
Best Regards,
J.
> arch/arm/Kconfig | 6 ++++
> arch/arm/boards/eukrea_cpuimx25/eukrea_cpuimx25.c | 3 +-
> arch/arm/boards/eukrea_cpuimx35/flash_header.c | 3 +-
> arch/arm/boards/eukrea_cpuimx51/flash_header.c | 3 +-
> arch/arm/boards/freescale-mx25-3-stack/3stack.c | 3 +-
> .../boards/freescale-mx35-3-stack/flash_header.c | 3 +-
> arch/arm/boards/freescale-mx51-pdk/flash_header.c | 3 +-
> arch/arm/boards/freescale-mx53-loco/flash_header.c | 3 +-
> arch/arm/boards/freescale-mx53-smd/flash_header.c | 3 +-
> arch/arm/cpu/mmu.c | 4 +-
> arch/arm/cpu/start.c | 20 ++++++++------
> arch/arm/include/asm/barebox-arm-head.h | 28 ++++++++++++++++++++
> arch/arm/include/asm/barebox-arm.h | 2 +
> arch/arm/lib/barebox.lds.S | 5 +++-
> 14 files changed, 69 insertions(+), 20 deletions(-)
> create mode 100644 arch/arm/include/asm/barebox-arm-head.h
>
> diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
> index b600179..b0b8f9c 100644
> --- a/arch/arm/Kconfig
> +++ b/arch/arm/Kconfig
> @@ -26,6 +26,12 @@ config ARM_LINUX
> default y
> depends on CMD_BOOTZ || CMD_BOOTU || CMD_BOOTM
>
> +config ARM_CUSTOM_HEAD
> + bool
> + help
> + specify a board or architecture specific custom head
> + function
> +
> menu "System Type "
>
> choice
> diff --git a/arch/arm/boards/eukrea_cpuimx25/eukrea_cpuimx25.c b/arch/arm/boards/eukrea_cpuimx25/eukrea_cpuimx25.c
> index 162c117..c7b0d2d 100644
> --- a/arch/arm/boards/eukrea_cpuimx25/eukrea_cpuimx25.c
> +++ b/arch/arm/boards/eukrea_cpuimx25/eukrea_cpuimx25.c
> @@ -46,13 +46,14 @@
> #include <usb/fsl_usb2.h>
> #include <mach/usb.h>
> #include <mach/devices-imx25.h>
> +#include <asm/barebox-arm-head.h>
>
> extern unsigned long _stext;
> extern void exception_vectors(void);
>
> void __naked __flash_header_start go(void)
> {
> - __asm__ __volatile__("b exception_vectors\n");
> + barebox_arm_default_head();
> }
>
> struct imx_dcd_entry __dcd_entry_section dcd_entry[] = {
> diff --git a/arch/arm/boards/eukrea_cpuimx35/flash_header.c b/arch/arm/boards/eukrea_cpuimx35/flash_header.c
> index 93c8348..4ded270 100644
> --- a/arch/arm/boards/eukrea_cpuimx35/flash_header.c
> +++ b/arch/arm/boards/eukrea_cpuimx35/flash_header.c
> @@ -1,12 +1,13 @@
> #include <common.h>
> #include <mach/imx-flash-header.h>
> #include <mach/imx-regs.h>
> +#include <asm/barebox-arm-head.h>
>
> extern void exception_vectors(void);
>
> void __naked __flash_header_start go(void)
> {
> - __asm__ __volatile__("b exception_vectors\n");
> + barebox_arm_default_head();
> }
>
> struct imx_dcd_entry __dcd_entry_section dcd_entry[] = {
> diff --git a/arch/arm/boards/eukrea_cpuimx51/flash_header.c b/arch/arm/boards/eukrea_cpuimx51/flash_header.c
> index f953b09..4f29dd9 100644
> --- a/arch/arm/boards/eukrea_cpuimx51/flash_header.c
> +++ b/arch/arm/boards/eukrea_cpuimx51/flash_header.c
> @@ -1,11 +1,12 @@
> #include <common.h>
> #include <mach/imx-flash-header.h>
> +#include <asm/barebox-arm-head.h>
>
> extern unsigned long _stext;
>
> void __naked __flash_header_start go(void)
> {
> - __asm__ __volatile__("b exception_vectors\n");
> + barebox_arm_default_head();
> }
>
> struct imx_dcd_entry __dcd_entry_section dcd_entry[] = {
> diff --git a/arch/arm/boards/freescale-mx25-3-stack/3stack.c b/arch/arm/boards/freescale-mx25-3-stack/3stack.c
> index 5aa54e4..78b872c 100644
> --- a/arch/arm/boards/freescale-mx25-3-stack/3stack.c
> +++ b/arch/arm/boards/freescale-mx25-3-stack/3stack.c
> @@ -42,13 +42,14 @@
> #include <i2c/i2c.h>
> #include <mfd/mc34704.h>
> #include <mach/devices-imx25.h>
> +#include <asm/barebox-arm-head.h>
>
> extern unsigned long _stext;
> extern void exception_vectors(void);
>
> void __naked __flash_header_start go(void)
> {
> - __asm__ __volatile__("b exception_vectors\n");
> + barebox_arm_default_head();
> }
>
> struct imx_dcd_entry __dcd_entry_section dcd_entry[] = {
> diff --git a/arch/arm/boards/freescale-mx35-3-stack/flash_header.c b/arch/arm/boards/freescale-mx35-3-stack/flash_header.c
> index 4bee797..63c1502 100644
> --- a/arch/arm/boards/freescale-mx35-3-stack/flash_header.c
> +++ b/arch/arm/boards/freescale-mx35-3-stack/flash_header.c
> @@ -1,12 +1,13 @@
> #include <common.h>
> #include <mach/imx-flash-header.h>
> #include <mach/imx-regs.h>
> +#include <asm/barebox-arm-head.h>
>
> extern void exception_vectors(void);
>
> void __naked __flash_header_start go(void)
> {
> - __asm__ __volatile__("b exception_vectors\n");
> + barebox_arm_default_head();
> }
>
> struct imx_dcd_entry __dcd_entry_section dcd_entry[] = {
> diff --git a/arch/arm/boards/freescale-mx51-pdk/flash_header.c b/arch/arm/boards/freescale-mx51-pdk/flash_header.c
> index 5f94506..d513c8c 100644
> --- a/arch/arm/boards/freescale-mx51-pdk/flash_header.c
> +++ b/arch/arm/boards/freescale-mx51-pdk/flash_header.c
> @@ -1,11 +1,12 @@
> #include <common.h>
> #include <mach/imx-flash-header.h>
> +#include <asm/barebox-arm-head.h>
>
> extern unsigned long _stext;
>
> void __naked __flash_header_start go(void)
> {
> - __asm__ __volatile__("b exception_vectors\n");
> + barebox_arm_default_head();
> }
>
> struct imx_dcd_entry __dcd_entry_section dcd_entry[] = {
> diff --git a/arch/arm/boards/freescale-mx53-loco/flash_header.c b/arch/arm/boards/freescale-mx53-loco/flash_header.c
> index 490e223..105f54a 100644
> --- a/arch/arm/boards/freescale-mx53-loco/flash_header.c
> +++ b/arch/arm/boards/freescale-mx53-loco/flash_header.c
> @@ -16,10 +16,11 @@
> #include <common.h>
> #include <asm/byteorder.h>
> #include <mach/imx-flash-header.h>
> +#include <asm/barebox-arm-head.h>
>
> void __naked __flash_header_start go(void)
> {
> - __asm__ __volatile__("b exception_vectors\n");
> + barebox_arm_default_head();
> }
>
> struct imx_dcd_v2_entry __dcd_entry_section dcd_entry[] = {
> diff --git a/arch/arm/boards/freescale-mx53-smd/flash_header.c b/arch/arm/boards/freescale-mx53-smd/flash_header.c
> index 490e223..105f54a 100644
> --- a/arch/arm/boards/freescale-mx53-smd/flash_header.c
> +++ b/arch/arm/boards/freescale-mx53-smd/flash_header.c
> @@ -16,10 +16,11 @@
> #include <common.h>
> #include <asm/byteorder.h>
> #include <mach/imx-flash-header.h>
> +#include <asm/barebox-arm-head.h>
>
> void __naked __flash_header_start go(void)
> {
> - __asm__ __volatile__("b exception_vectors\n");
> + barebox_arm_default_head();
> }
>
> struct imx_dcd_v2_entry __dcd_entry_section dcd_entry[] = {
> diff --git a/arch/arm/cpu/mmu.c b/arch/arm/cpu/mmu.c
> index c6c91df..e8ff676 100644
> --- a/arch/arm/cpu/mmu.c
> +++ b/arch/arm/cpu/mmu.c
> @@ -4,6 +4,7 @@
> #include <errno.h>
> #include <sizes.h>
> #include <asm/memory.h>
> +#include <asm/barebox-arm.h>
> #include <asm/system.h>
> #include <memory.h>
>
> @@ -182,7 +183,6 @@ static void vectors_init(void)
> {
> u32 *exc, *zero = NULL;
> void *vectors;
> - extern unsigned long exception_vectors;
> u32 cr;
>
> cr = get_cr();
> @@ -210,7 +210,7 @@ static void vectors_init(void)
>
> vectors = xmemalign(PAGE_SIZE, PAGE_SIZE);
> memset(vectors, 0, PAGE_SIZE);
> - memcpy(vectors, &exception_vectors, ARM_VECTORS_SIZE);
> + memcpy(vectors, __exceptions_start, __exceptions_stop - __exceptions_start);
>
> if (cr & CR_V)
> exc[256 - 16] = (u32)vectors | PTE_TYPE_SMALL | PTE_FLAGS_CACHED;
> diff --git a/arch/arm/cpu/start.c b/arch/arm/cpu/start.c
> index 5e09300..e78d749 100644
> --- a/arch/arm/cpu/start.c
> +++ b/arch/arm/cpu/start.c
> @@ -23,14 +23,22 @@
> #include <common.h>
> #include <init.h>
> #include <asm/barebox-arm.h>
> +#include <asm/barebox-arm-head.h>
> #include <asm/system.h>
> #include <asm-generic/memory_layout.h>
> #include <asm/sections.h>
>
> -void __naked __section(.text_entry) exception_vectors(void)
> +#ifndef CONFIG_ARM_CUSTOM_HEAD
> +void __naked __section(.text_entry) barebox_arm_head(void)
> +{
> + barebox_arm_default_head();
> +}
> +#endif
> +
> +void __naked __section(.text_exceptions) exception_vectors(void)
> {
> __asm__ __volatile__ (
> - "b reset\n" /* reset */
> + "b start_arm_barebox\n" /* reset */
> #ifdef CONFIG_ARM_EXCEPTIONS
> "ldr pc, =undefined_instruction\n" /* undefined instruction */
> "ldr pc, =software_interrupt\n" /* software interrupt (SWI) */
> @@ -48,12 +56,6 @@ void __naked __section(.text_entry) exception_vectors(void)
> "1: bne 1b\n" /* irq (interrupt) */
> "1: bne 1b\n" /* fiq (fast interrupt) */
> #endif
> - ".word 0x65726162\n" /* 'bare' */
> - ".word 0x00786f62\n" /* 'box' */
> - ".word _text\n" /* text base. If copied there,
> - * barebox can skip relocation
> - */
> - ".word _barebox_image_size\n" /* image size to copy */
> );
> }
>
> @@ -61,7 +63,7 @@ void __naked __section(.text_entry) exception_vectors(void)
> * The actual reset vector. This code is position independent and usually
> * does not run at the address it's linked at.
> */
> -void __naked __bare_init reset(void)
> +void __naked __bare_init start_arm_barebox(void)
> {
> uint32_t r;
>
> diff --git a/arch/arm/include/asm/barebox-arm-head.h b/arch/arm/include/asm/barebox-arm-head.h
> new file mode 100644
> index 0000000..72ad8ec
> --- /dev/null
> +++ b/arch/arm/include/asm/barebox-arm-head.h
> @@ -0,0 +1,28 @@
> +#ifndef __BAREBOX_ARM_HEAD_H
> +#define __BAREBOX_ARM_HEAD_H
> +
> +#ifndef ARM_EXCEPTION_VECTOR_6
> +#define ARM_EXCEPTION_VECTOR_6 ".word 0x0\n"
> +#endif
> +
> +static inline void barebox_arm_default_head(void)
> +{
> + __asm__ __volatile__ (
> + "b start_arm_barebox\n"
> + ".word 0x0\n"
> + ".word 0x0\n"
> + ".word 0x0\n"
> + ".word 0x0\n"
> + ARM_EXCEPTION_VECTOR_6
> + ".word 0x0\n"
> + ".word 0x0\n"
> + ".word 0x65726162\n" /* 'bare' */
> + ".word 0x00786f62\n" /* 'box' */
> + ".word _text\n" /* text base. If copied there,
> + * barebox can skip relocation
> + */
> + ".word _barebox_image_size\n" /* image size to copy */
> + );
> +}
> +
> +#endif /* __BAREBOX_ARM_HEAD_H */
> diff --git a/arch/arm/include/asm/barebox-arm.h b/arch/arm/include/asm/barebox-arm.h
> index 7bb1af1..3339782 100644
> --- a/arch/arm/include/asm/barebox-arm.h
> +++ b/arch/arm/include/asm/barebox-arm.h
> @@ -36,6 +36,8 @@ int cleanup_before_linux(void);
> int board_init(void);
> int dram_init (void);
>
> +extern char __exceptions_start[], __exceptions_stop[];
> +
> void board_init_lowlevel(void);
> void board_init_lowlevel_return(void);
> void arch_init_lowlevel(void);
> diff --git a/arch/arm/lib/barebox.lds.S b/arch/arm/lib/barebox.lds.S
> index f05f345..f0d675b 100644
> --- a/arch/arm/lib/barebox.lds.S
> +++ b/arch/arm/lib/barebox.lds.S
> @@ -26,7 +26,7 @@
>
> OUTPUT_FORMAT("elf32-littlearm", "elf32-littlearm", "elf32-littlearm")
> OUTPUT_ARCH(arm)
> -ENTRY(exception_vectors)
> +ENTRY(barebox_arm_head)
> SECTIONS
> {
> . = TEXT_BASE;
> @@ -45,6 +45,9 @@ SECTIONS
> LONG(0x53555243) /* 'CRUS' */
> #endif
> *(.text_bare_init*)
> + __exceptions_start = .;
> + KEEP(*(.text_exceptions*))
> + __exceptions_stop = .;
> *(.text*)
> }
>
> --
> 1.7.7.3
>
>
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