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

[Andre Przywara <andre.przywara@linaro.org>]

On 12/02/2013 04:07 PM, Ian Campbell wrote:
> 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@linaro.org>
>> ---
>>   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?

Indeed. Not for all functions and parameters, but for the start address 
at least that makes sense ;-)
Is there a type in Xen which reliably holds a native word? ulong or 
something?

Thanks,
Andre.


>
>> +{
>> +    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);
>
>