Re: [Xen-devel] [PATCH v2 4/6] arm: add a function to invoke the PSCI handler

[Ian Campbell <Ian.Campbell@xxxxxxxxxx>]

On Mon, 2013-12-02 at 12:08 +0100, Andre Przywara wrote:
> The PSCI handler is invoked via a secure monitor call with the
> arguments defined in registers. Copy the function from the
> Linux code and adjust it to work on both ARM32 and ARM64.
> 
> Signed-off-by: Andre Przywara <andre.przywara@xxxxxxxxxx>
> ---
>  xen/arch/arm/psci.c        | 28 ++++++++++++++++++++++++++++
>  xen/include/asm-arm/psci.h |  1 +
>  2 files changed, 29 insertions(+)
> 
> diff --git a/xen/arch/arm/psci.c b/xen/arch/arm/psci.c
> index 9ff06cd..cc382be 100644
> --- a/xen/arch/arm/psci.c
> +++ b/xen/arch/arm/psci.c
> @@ -25,8 +25,36 @@
>  
>  int psci_available;
>  
> +#ifdef CONFIG_ARM_32
> +#define REG_PREFIX "r"
> +#else
> +#define REG_PREFIX "x"
> +#endif
> +
> +static noinline int __invoke_psci_fn_smc(u32 function_id, u32 arg0, u32 arg1,
> +                                         u32 arg2)

I should reread the PSCI spec, but are these not 64-bit on AArch64?

> +{
> +    asm volatile(
> +        __asmeq("%0", REG_PREFIX"0")
> +        __asmeq("%1", REG_PREFIX"1")
> +        __asmeq("%2", REG_PREFIX"2")
> +        __asmeq("%3", REG_PREFIX"3")
> +        "smc #0"
> +        : "+r" (function_id)
> +        : "r" (arg0), "r" (arg1), "r" (arg2));
> +
> +    return function_id;
> +}
> +
> +#undef REG_PREFIX
> +
>  static uint32_t psci_cpu_on_nr;
>  
> +int call_psci_cpu_on(int cpu, void *smp_pen)
> +{
> +    return __invoke_psci_fn_smc(psci_cpu_on_nr, cpu, __pa(smp_pen), 0);
> +}
> +
>  int __init psci_init(void)
>  {
>      struct dt_device_node *psci;
> diff --git a/xen/include/asm-arm/psci.h b/xen/include/asm-arm/psci.h
> index 2f37612..50513bf 100644
> --- a/xen/include/asm-arm/psci.h
> +++ b/xen/include/asm-arm/psci.h
> @@ -10,6 +10,7 @@
>  extern int psci_available;
>  
>  int psci_init(void);
> +int call_psci_cpu_on(int cpu, void *smp_pen);
>  
>  /* functions to handle guest PSCI requests */
>  int do_psci_cpu_on(uint32_t vcpuid, register_t entry_point);



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