Re: [PATCH v1] arm/optee: Use only least 32 bits for SMC type arg according to SMCCC

[Volodymyr Babchuk <Volodymyr_Babchuk@epam.com>]

Hi Roman,

Thank you for the contribution.

Roman Skakun writes:

> This patch added additional sanity and increases an understanding for
> getting proper value from the first argument for SMC call on aarch64
> according to SMCC Convention.
>
> [0] ARM DEN0028B, page 12
>
> Signed-off-by: Roman Skakun <roman_skakun@epam.com>

Acked-by: Volodymyr Babchyk <volodymyr_babchuk@epam.com>

> ---
>  xen/arch/arm/tee/optee.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/xen/arch/arm/tee/optee.c b/xen/arch/arm/tee/optee.c
> index ee85359742..87060b52b8 100644
> --- a/xen/arch/arm/tee/optee.c
> +++ b/xen/arch/arm/tee/optee.c
> @@ -1643,7 +1643,8 @@ static bool optee_handle_call(struct cpu_user_regs *regs)
>      if ( !ctx )
>          return false;
>  
> -    switch ( get_user_reg(regs, 0) )
> +    /* Only least 32 bits are significant (see ARM DEN 0028B, page 12) */
> +    switch ( (uint32_t)get_user_reg(regs, 0) )
>      {
>      case OPTEE_SMC_CALLS_COUNT:
>          set_user_reg(regs, 0, OPTEE_MEDIATOR_SMC_COUNT);


-- 
Volodymyr Babchuk at EPAM