Re: [PATCH master v3 1/2] ARM: MXS: fix breakage for non-DT boards

[Bastian Krause <bst@xxxxxxxxxxxxxx>]

On 10/11/22 13:49, Ahmad Fatoum wrote:
> boarddata, the third argument passed from barebox PBL to barebox proper,
> is usually either a pointer to an optionally compressed flattened device tree
> or a machien type integer casted to a pointer.
>
> In order to support device trees located in the first 8192 bytes of
> address space, barebox has been trying to dereference boarddata, before
> falling back to treating it as integer.
>
> This resulted in breakage as boarddata may be an integer not divisible
> by 4 and thus an unaligned exception would occur.
>
> The already existing barebox_arm_boarddata mechanism sidesteps this
> issue: With it, the machine type integer is not passed as is, but the
> address of a suitably aligned structure that contains it is passed
> instead.
>
> Searching for MACH_TYPE in arch/arm/boards shows 5 boards to be
> affected in-tree, which are all fixed with this commit.
>
> Fixes: 390bc7834ffc ("ARM: start: check for machine type last")
> Signed-off-by: Ahmad Fatoum <a.fatoum@xxxxxxxxxxxxxx>

Tested-by: Bastian Krause <bst@xxxxxxxxxxxxxx>

Regards,
Bastian

> ---
> v2 -> v3:
>    - move variable reference into non-naked noinline function (Sascha)
> v1 -> v2:
>    - Do full relocation instead of get_runtime_offset(). This is
>      required, because GCC[1] generated a pc-relative reference
>      to boarddata as it's in the same translation unit and as
>      such get_runtime_offset() being added was wrong.
>      Instead of relying on compiler whims, we instead set up
>      a full C environment and play it safe.
>    -  s/MACHINE_TYPE/MACH_TYPE/ (Bastian)
> ---
>   arch/arm/boards/chumby_falconwing/lowlevel.c     | 16 +++++++++++++++-
>   arch/arm/boards/crystalfontz-cfa10036/lowlevel.c | 16 +++++++++++++++-
>   arch/arm/boards/freescale-mx23-evk/lowlevel.c    | 16 +++++++++++++++-
>   arch/arm/boards/imx233-olinuxino/lowlevel.c      | 15 ++++++++++++++-
>   arch/arm/boards/karo-tx28/lowlevel.c             | 15 ++++++++++++++-
>   5 files changed, 73 insertions(+), 5 deletions(-)
>
> diff --git a/arch/arm/boards/chumby_falconwing/lowlevel.c b/arch/arm/boards/chumby_falconwing/lowlevel.c
> index 091dd1955260..f0c3143e8d03 100644
> --- a/arch/arm/boards/chumby_falconwing/lowlevel.c
> +++ b/arch/arm/boards/chumby_falconwing/lowlevel.c
> @@ -7,8 +7,22 @@
>   #include <mach/imx23-regs.h>
>   #include <generated/mach-types.h>
>   
> +static noinline void continue_imx_entry(size_t size)
> +{
> +	static struct barebox_arm_boarddata boarddata = {
> +		.magic = BAREBOX_ARM_BOARDDATA_MAGIC,
> +		.machine = MACH_TYPE_CHUMBY,
> +	};
> +
> +	barebox_arm_entry(IMX_MEMORY_BASE, size, &boarddata);
> +}
> +
>   ENTRY_FUNCTION(start_chumby_falconwing, r0, r1, r2)
>   {
>   	arm_cpu_lowlevel_init();
> -	barebox_arm_entry(IMX_MEMORY_BASE, SZ_64M, (void *)MACH_TYPE_CHUMBY);
> +
> +	relocate_to_current_adr();
> +	setup_c();
> +
> +	continue_imx_entry(SZ_64M);
>   }
> diff --git a/arch/arm/boards/crystalfontz-cfa10036/lowlevel.c b/arch/arm/boards/crystalfontz-cfa10036/lowlevel.c
> index 92b42aa89350..8ebea0fedc9c 100644
> --- a/arch/arm/boards/crystalfontz-cfa10036/lowlevel.c
> +++ b/arch/arm/boards/crystalfontz-cfa10036/lowlevel.c
> @@ -7,8 +7,22 @@
>   #include <mach/imx28-regs.h>
>   #include <generated/mach-types.h>
>   
> +static noinline void continue_imx_entry(size_t size)
> +{
> +	static struct barebox_arm_boarddata boarddata = {
> +		.magic = BAREBOX_ARM_BOARDDATA_MAGIC,
> +		.machine = MACH_TYPE_CFA10036,
> +	};
> +
> +	barebox_arm_entry(IMX_MEMORY_BASE, size, &boarddata);
> +}
> +
>   ENTRY_FUNCTION(start_cfa10036, r0, r1, r2)
>   {
>   	arm_cpu_lowlevel_init();
> -	barebox_arm_entry(IMX_MEMORY_BASE, SZ_128M, (void *)MACH_TYPE_CFA10036);
> +
> +	relocate_to_current_adr();
> +	setup_c();
> +
> +	continue_imx_entry(SZ_128M);
>   }
> diff --git a/arch/arm/boards/freescale-mx23-evk/lowlevel.c b/arch/arm/boards/freescale-mx23-evk/lowlevel.c
> index 62560bbff733..319e9784a4fd 100644
> --- a/arch/arm/boards/freescale-mx23-evk/lowlevel.c
> +++ b/arch/arm/boards/freescale-mx23-evk/lowlevel.c
> @@ -7,8 +7,22 @@
>   #include <asm/barebox-arm.h>
>   #include <mach/imx23-regs.h>
>   
> +static noinline void continue_imx_entry(size_t size)
> +{
> +	static struct barebox_arm_boarddata boarddata = {
> +		.magic = BAREBOX_ARM_BOARDDATA_MAGIC,
> +		.machine = MACH_TYPE_MX23EVK,
> +	};
> +
> +	barebox_arm_entry(IMX_MEMORY_BASE, size, &boarddata);
> +}
> +
>   ENTRY_FUNCTION(start_imx23_evk, r0, r1, r2)
>   {
>   	arm_cpu_lowlevel_init();
> -	barebox_arm_entry(IMX_MEMORY_BASE, SZ_32M, (void *)MACH_TYPE_MX23EVK);
> +
> +	relocate_to_current_adr();
> +	setup_c();
> +
> +	continue_imx_entry(SZ_32M);
>   }
> diff --git a/arch/arm/boards/imx233-olinuxino/lowlevel.c b/arch/arm/boards/imx233-olinuxino/lowlevel.c
> index 71fc379f0487..6e80e6889b51 100644
> --- a/arch/arm/boards/imx233-olinuxino/lowlevel.c
> +++ b/arch/arm/boards/imx233-olinuxino/lowlevel.c
> @@ -11,9 +11,22 @@
>   #include <mach/iomux.h>
>   #include <generated/mach-types.h>
>   
> +static noinline void continue_imx_entry(size_t size)
> +{
> +	static struct barebox_arm_boarddata boarddata = {
> +		.magic = BAREBOX_ARM_BOARDDATA_MAGIC,
> +		.machine = MACH_TYPE_IMX233_OLINUXINO,
> +	};
> +
> +	barebox_arm_entry(IMX_MEMORY_BASE, size, &boarddata);
> +}
> +
>   ENTRY_FUNCTION(start_barebox_olinuxino_imx23, r0, r1, r2)
>   {
> -	barebox_arm_entry(IMX_MEMORY_BASE, SZ_64M, (void *)MACH_TYPE_IMX233_OLINUXINO);
> +	relocate_to_current_adr();
> +	setup_c();
> +
> +	continue_imx_entry(SZ_64M);
>   }
>   
>   static const uint32_t pad_setup[] = {
> diff --git a/arch/arm/boards/karo-tx28/lowlevel.c b/arch/arm/boards/karo-tx28/lowlevel.c
> index 28d96f3e1a5f..9e90e40926e8 100644
> --- a/arch/arm/boards/karo-tx28/lowlevel.c
> +++ b/arch/arm/boards/karo-tx28/lowlevel.c
> @@ -15,9 +15,22 @@
>   #include <stmp-device.h>
>   #include <generated/mach-types.h>
>   
> +static noinline void continue_imx_entry(size_t size)
> +{
> +	static struct barebox_arm_boarddata boarddata = {
> +		.magic = BAREBOX_ARM_BOARDDATA_MAGIC,
> +		.machine = MACH_TYPE_TX28,
> +	};
> +
> +	barebox_arm_entry(IMX_MEMORY_BASE, size, &boarddata);
> +}
> +
>   ENTRY_FUNCTION(start_barebox_karo_tx28, r0, r1, r2)
>   {
> -	barebox_arm_entry(IMX_MEMORY_BASE, SZ_128M, (void *)MACH_TYPE_TX28);
> +	relocate_to_current_adr();
> +	setup_c();
> +
> +	continue_imx_entry(SZ_128M);
>   }
>   
>   static const uint32_t iomux_pads[] = {

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