Re: [PATCH v7 10/11] arm: vsmc: remove 64 bit mode check in PSCI handler

From: Julien Grall <julien.grall@arm.com>
To: Volodymyr Babchuk <volodymyr_babchuk@epam.com>,
	xen-devel@lists.xen.org,
	Stefano Stabellini <sstabellini@kernel.org>
Cc: "Edgar E . Iglesias" <edgar.iglesias@xilinx.com>
Subject: Re: [PATCH v7 10/11] arm: vsmc: remove 64 bit mode check in PSCI handler
Date: Fri, 6 Oct 2017 15:00:32 +0100	[thread overview]
Message-ID: <6bf87d3b-4357-f8dc-ddc5-51e324d70eb3@arm.com> (raw)
In-Reply-To: <1507150827-7858-11-git-send-email-volodymyr_babchuk@epam.com>

Hi Volodymyr,

On 04/10/17 22:00, Volodymyr Babchuk wrote:
> PSCI handling code had helper routine that checked calling convention.
> It does not needed anymore, because:
> 
>   - Generic handler checks that 64 bit calls can be made only by
>     64 bit guests.
> 
>   - SMCCC requires that 64-bit handler should support both 32 and 64 bit
>     calls even if they originate from 64 bit caller.
> 
> This patch removes that extra check.
> 
> Signed-off-by: Volodymyr Babchuk <volodymyr_babchuk@epam.com>
> Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>

Sorry I just noticed this. This is odd to keep a reviewed-by from 
Stefano in a patch that changed quite a bit since he gave it (patch #2).

Usually reviewed-by means the person has reviewed the code and happy 
with it. Technically, he didn't review the new changes and if not 
dropped, you should have at least asked whether he is happy with it.

Stefano are you happy if Volodymyr keeping your tag?

> ---
>   xen/arch/arm/vsmc.c | 62 ++++++++++++++++++++++-------------------------------
>   1 file changed, 26 insertions(+), 36 deletions(-)
> 
> diff --git a/xen/arch/arm/vsmc.c b/xen/arch/arm/vsmc.c
> index 77fc915..ff84442 100644
> --- a/xen/arch/arm/vsmc.c
> +++ b/xen/arch/arm/vsmc.c
> @@ -135,12 +135,6 @@ static bool handle_existing_apis(struct cpu_user_regs *regs)
>       }
>   }
>   
> -/* helper function for checking arm mode 32/64 bit */
> -static inline int psci_mode_check(struct domain *d, uint32_t fid)
> -{
> -    return is_64bit_domain(d) || !smccc_is_conv_64(fid);
> -}
> -
>   /* PSCI 0.2 interface and other Standard Secure Calls */
>   static bool handle_sssc(struct cpu_user_regs *regs)
>   {
> @@ -165,8 +159,7 @@ static bool handle_sssc(struct cpu_user_regs *regs)
>   
>       case PSCI_0_2_FN_MIGRATE_INFO_UP_CPU:
>           perfc_incr(vpsci_migrate_info_up_cpu);
> -        if ( psci_mode_check(current->domain, fid) )
> -            PSCI_SET_RESULT(regs, do_psci_0_2_migrate_info_up_cpu());
> +        PSCI_SET_RESULT(regs, do_psci_0_2_migrate_info_up_cpu());
>           return true;
>   
>       case PSCI_0_2_FN_SYSTEM_OFF:
> @@ -182,48 +175,45 @@ static bool handle_sssc(struct cpu_user_regs *regs)
>           return true;
>   
>       case PSCI_0_2_FN_CPU_ON:
> -        perfc_incr(vpsci_cpu_on);
> -        if ( psci_mode_check(current->domain, fid) )
> -        {
> -            register_t vcpuid = PSCI_ARG(regs, 1);
> -            register_t epoint = PSCI_ARG(regs, 2);
> -            register_t cid = PSCI_ARG(regs, 3);
> +    {
> +        register_t vcpuid = PSCI_ARG(regs, 1);
> +        register_t epoint = PSCI_ARG(regs, 2);
> +        register_t cid = PSCI_ARG(regs, 3);
>   
> -            PSCI_SET_RESULT(regs, do_psci_0_2_cpu_on(vcpuid, epoint, cid));
> -        }
> +        perfc_incr(vpsci_cpu_on);
> +        PSCI_SET_RESULT(regs, do_psci_0_2_cpu_on(vcpuid, epoint, cid));
>           return true;
> +    }
>   
>       case PSCI_0_2_FN_CPU_SUSPEND:
> -        perfc_incr(vpsci_cpu_suspend);
> -        if ( psci_mode_check(current->domain, fid) )
> -        {
> -            uint32_t pstate = PSCI_ARG32(regs, 1);
> -            register_t epoint = PSCI_ARG(regs, 2);
> -            register_t cid = PSCI_ARG(regs, 3);
> +    {
> +        uint32_t pstate = PSCI_ARG32(regs, 1);
> +        register_t epoint = PSCI_ARG(regs, 2);
> +        register_t cid = PSCI_ARG(regs, 3);
>   
> -            PSCI_SET_RESULT(regs, do_psci_0_2_cpu_suspend(pstate, epoint, cid));
> -        }
> +        perfc_incr(vpsci_cpu_suspend);
> +        PSCI_SET_RESULT(regs, do_psci_0_2_cpu_suspend(pstate, epoint, cid));
>           return true;
> +    }
>   
>       case PSCI_0_2_FN_AFFINITY_INFO:
> +    {
> +        register_t taff = PSCI_ARG(regs, 1);
> +        uint32_t laff = PSCI_ARG32(regs, 2);
> +
>           perfc_incr(vpsci_cpu_affinity_info);
> -        if ( psci_mode_check(current->domain, fid) )
> -        {
> -            register_t taff = PSCI_ARG(regs, 1);
> -            uint32_t laff = PSCI_ARG32(regs, 2);
> -            PSCI_SET_RESULT(regs, do_psci_0_2_affinity_info(taff, laff));
> -        }
> +        PSCI_SET_RESULT(regs, do_psci_0_2_affinity_info(taff, laff));
>           return true;
> +    }
>   
>       case PSCI_0_2_FN_MIGRATE:
> -        perfc_incr(vpsci_cpu_migrate);
> -        if ( psci_mode_check(current->domain, fid) )
> -        {
> -            uint32_t tcpu = PSCI_ARG32(regs, 1);
> +    {
> +        uint32_t tcpu = PSCI_ARG32(regs, 1);
>   
> -            PSCI_SET_RESULT(regs, do_psci_0_2_migrate(tcpu));
> -        }
> +        perfc_incr(vpsci_cpu_migrate);
> +        PSCI_SET_RESULT(regs, do_psci_0_2_migrate(tcpu));
>           return true;
> +    }
>   
>       case ARM_SMCCC_FUNC_CALL_COUNT:
>           return fill_function_call_count(regs, SSSC_SMCCC_FUNCTION_COUNT);
> 

-- 
Julien Grall

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