Re: [PATCH v3] tee: remove TZMEM_MODE_GENERIC

[Nathan Chancellor]

On Fri, Aug 07, 2026 at 06:50:41PM +0100, Julian Braha wrote:
> 'select' does not work on config options in a 'choice', so currently it is
> possible to enable QCOMTEE without QCOM_TZMEM_MODE_SHMBRIDGE, even though
> this is needed at runtime.
> 
> There are no users of the generic allocator option,
> QCOM_TZMEM_MODE_GENERIC, so let's remove it. Then, we can remove the
> containing choice..endchoice, which allows the 'select' to work as
> intended.
> 
> Suggested-by: Arnd Bergmann <arnd@xxxxxxxx>
> Signed-off-by: Julian Braha <julianbraha@xxxxxxxxx>

Reviewed-by: Nathan Chancellor <nathan@xxxxxxxxxx>

One small nit below but I would only send v4 if there are other things
to be addressed.

A note to the maintainers: We would like to turn selecting a choice
symbol into a hard error in 7.4, so please consider picking this up for
7.3-rc1.

> ---
> Changes since v2:
> - add back stubs for when CONFIG_QCOM_TZMEM_MODE_GENERIC=n
> - updated help text accordingly
> 
> Link:
> https://lore.kernel.org/all/20260729203845.387239-1-julianbraha@xxxxxxxxx/
> 
> Changes since v1:
> - remove TZMEM_MODE_GENERIC instead of removing the dead select
> 
> Link:
> https://lore.kernel.org/all/20260715092539.18384-1-julianbraha@xxxxxxxxx/
> ---
>  drivers/firmware/qcom/Kconfig      | 26 +++++---------------------
>  drivers/firmware/qcom/qcom_tzmem.c |  4 ++--
>  2 files changed, 7 insertions(+), 23 deletions(-)
> 
> diff --git a/drivers/firmware/qcom/Kconfig b/drivers/firmware/qcom/Kconfig
> index c7f8413ab996..95b968d88dc3 100644
> --- a/drivers/firmware/qcom/Kconfig
> +++ b/drivers/firmware/qcom/Kconfig
> @@ -34,33 +34,17 @@ config QCOM_TZMEM
>  	tristate
>  	select GENERIC_ALLOCATOR
>  
> -choice
> -	prompt "TrustZone interface memory allocator mode"
> -	depends on QCOM_TZMEM
> -	default QCOM_TZMEM_MODE_GENERIC
> -	help
> -	  Selects the mode of the memory allocator providing memory buffers of
> -	  suitable format for sharing with the TrustZone. If in doubt, select
> -	  'Generic'.
> -
> -config QCOM_TZMEM_MODE_GENERIC
> -	bool "Generic"
> -	help
> -	  Use the generic allocator mode. The memory is page-aligned, non-cachable
> -	  and physically contiguous.
> -
>  config QCOM_TZMEM_MODE_SHMBRIDGE
> -	bool "SHM Bridge"
> +	bool "TrustZone interface memory allocator: SHM Bridge"
> +	depends on QCOM_TZMEM
>  	help
> -	  Use Qualcomm Shared Memory Bridge. The memory has the same alignment as
> -	  in the 'Generic' allocator but is also explicitly marked as an SHM Bridge
> -	  buffer.
> +	  Use Qualcomm Shared Memory Bridge as memory allocator. The memory has the
> +	  same alignment as in the 'Generic' allocator, which is used when this option
> +	  is disabled, but is also explicitly marked as an SHM Bridge buffer.
>  
>  	  With this selected, all buffers passed to the TrustZone must be allocated
>  	  using the TZMem allocator or else the TrustZone will refuse to use them.
>  
> -endchoice
> -
>  config QCOM_QSEECOM
>  	bool "Qualcomm QSEECOM interface driver"
>  	depends on QCOM_SCM=y
> diff --git a/drivers/firmware/qcom/qcom_tzmem.c b/drivers/firmware/qcom/qcom_tzmem.c
> index 0fd9581275f1..510474902c3a 100644
> --- a/drivers/firmware/qcom/qcom_tzmem.c
> +++ b/drivers/firmware/qcom/qcom_tzmem.c
> @@ -50,7 +50,7 @@ static struct device *qcom_tzmem_dev;
>  static RADIX_TREE(qcom_tzmem_chunks, GFP_ATOMIC);
>  static DEFINE_SPINLOCK(qcom_tzmem_chunks_lock);
>  
> -#if IS_ENABLED(CONFIG_QCOM_TZMEM_MODE_GENERIC)
> +#ifndef CONFIG_QCOM_TZMEM_MODE_SHMBRIDGE

I realize you likely did this to keep the diff small but I think
negative conditional checks are harder to read than positive ones, so I
would consider making this an '#ifdef' and flipping the branches.

>  static int qcom_tzmem_init(void)
>  {
> @@ -67,7 +67,7 @@ static void qcom_tzmem_cleanup_area(struct qcom_tzmem_area *area)
>  
>  }
>  
> -#elif IS_ENABLED(CONFIG_QCOM_TZMEM_MODE_SHMBRIDGE)
> +#else
>  
>  #include <linux/firmware/qcom/qcom_scm.h>
>  #include <linux/of.h>
> -- 
> 2.55.0
> 

-- 
Cheers,
Nathan