[PATCH v7 08/10] mach-k3: common: enable falcon mode for 62 platform

[Tom Rini]

On Tue, Jun 03, 2025 at 07:54:48PM +0530, Anshul Dalal wrote:
> We use the spl_board_prepare_for_boot hook to call k3_falcon_prep which
> is ran after tispl is loaded but before jump_to_image.
> 
> In here, we find the boot media and load the image just as std falcon
> flow (since spl_start_uboot returns 0 now). Once the kernel and args are
> loaded, we perform fdt fixups on the fdt accompanying the kernel (if
> loaded as FIT) or the loaded up args and return.
> 
> Now when the flow goes to jump_to_image, we do the regular pre-jump
> procedure and jump to ATF which jumps to the kernel directly since we
> have already loaded the kernel and dtb at their respective addresses
> (PRELOADED_BL33_BASE and K3_HW_CONFIG_BASE).
> 
> Signed-off-by: Anshul Dalal <anshuld at ti.com>
> ---
>  arch/arm/mach-k3/common.c | 107 ++++++++++++++++++++++++++++++++++++++
>  1 file changed, 107 insertions(+)
> 
> diff --git a/arch/arm/mach-k3/common.c b/arch/arm/mach-k3/common.c
> index fc230f180d0..70317fec19c 100644
> --- a/arch/arm/mach-k3/common.c
> +++ b/arch/arm/mach-k3/common.c
> @@ -259,8 +259,115 @@ static __maybe_unused void k3_dma_remove(void)
>  		pr_warn("DMA Device not found (err=%d)\n", rc);
>  }
>  
> +#if IS_ENABLED(CONFIG_SPL_OS_BOOT) && !IS_ENABLED(CONFIG_ARM64)
> +static bool tispl_loaded;
> +
> +int spl_start_uboot(void)
> +{
> +	if (!tispl_loaded)
> +		return 1;
> +	return 0;
> +}
> +
> +static int k3_falcon_fdt_fixup(void *fdt)
> +{
> +	struct disk_partition info;
> +	struct blk_desc *dev_desc;
> +	char bootmedia[32];
> +	char bootpart[32];
> +	char str[256];
> +	int ret;
> +
> +	strcpy(bootmedia, env_get("boot"));
> +	strcpy(bootpart, env_get("bootpart"));

Since we're talking secure parts, strncpy is even more important, and
being aware of:
 * Note that unlike userspace strncpy, this does not %NUL-pad the buffer.
 * However, the result is not %NUL-terminated if the source exceeds
 * @count bytes.
from lib/string.c

> +	ret = blk_get_device_part_str(bootmedia, bootpart, &dev_desc, &info, 0);
> +	if (ret < 0)
> +		printf("Failed to get part details for %s %s [%d]\n", bootmedia,
> +		       bootpart, ret);

... and bail out?

I feel like all the changes here need a read with "and on failure in secure
mode what can someone abuse this to do" in mind.

-- 
Tom
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