[PATCH v4 4/6] powerpc/fsl: Enable cpu vulnerabilities reporting for NXP PPC BOOK3E

[Diana Madalina Craciun]

On 7/17/2018 7:47 PM, LEROY Christophe wrote:
> Diana Craciun <diana.craciun at nxp.com> a écrit :
>
>> The NXP PPC Book3E platforms are not vulnerable to meltdown and
>> Spectre v4, so make them PPC_BOOK3S_64 specific.
>>
>> Signed-off-by: Diana Craciun <diana.craciun at nxp.com>
>> ---
>> History:
>>
>> v2-->v3
>> - used the existing functions for spectre v1/v2
>>
>>  arch/powerpc/Kconfig           | 7 ++++++-
>>  arch/powerpc/kernel/security.c | 2 ++
>>  2 files changed, 8 insertions(+), 1 deletion(-)
>>
>> diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
>> index 9f2b75f..116c953 100644
>> --- a/arch/powerpc/Kconfig
>> +++ b/arch/powerpc/Kconfig
>> @@ -165,7 +165,7 @@ config PPC
>>  	select GENERIC_CLOCKEVENTS_BROADCAST	if SMP
>>  	select GENERIC_CMOS_UPDATE
>>  	select GENERIC_CPU_AUTOPROBE
>> -	select GENERIC_CPU_VULNERABILITIES	if PPC_BOOK3S_64
>> +	select GENERIC_CPU_VULNERABILITIES	if PPC_NOSPEC
> I don't understand.  You say this patch is to make something specific  
> to book3s64 specific, and you are creating a new config param that  
> make things less specific
>
> Christophe

In order to enable the vulnerabilities reporting on NXP socs I need to
enable them for PPC_FSL_BOOK3E. So they will be enabled for both
PPC_FSL_BOOK3E and PPC_BOOK3S_64. This is the reason for adding the
Kconfig. However this will enable: spectre v1/v2 and meltdown. NXP socs
are not vulnerable to meltdown, so I made the meltdown reporting
PPC_BOOK3S_64 specific. I guess I can have the PPC_NOSPEC definition in
a separate patch to be more clear.

Diana

>
>>  	select GENERIC_IRQ_SHOW
>>  	select GENERIC_IRQ_SHOW_LEVEL
>>  	select GENERIC_SMP_IDLE_THREAD
>> @@ -240,6 +240,11 @@ config PPC
>>  	# Please keep this list sorted alphabetically.
>>  	#
>>
>> +config PPC_NOSPEC
>> +    bool
>> +    default y
>> +    depends on PPC_BOOK3S_64 || PPC_FSL_BOOK3E
>> +
>>  config GENERIC_CSUM
>>  	def_bool n
>>
>> diff --git a/arch/powerpc/kernel/security.c b/arch/powerpc/kernel/security.c
>> index 3a4e5c3..539c744 100644
>> --- a/arch/powerpc/kernel/security.c
>> +++ b/arch/powerpc/kernel/security.c
>> @@ -92,6 +92,7 @@ static __init int barrier_nospec_debugfs_init(void)
>>  device_initcall(barrier_nospec_debugfs_init);
>>  #endif /* CONFIG_DEBUG_FS */
>>
>> +#ifdef CONFIG_PPC_BOOK3S_64
>>  ssize_t cpu_show_meltdown(struct device *dev, struct  
>> device_attribute *attr, char *buf)
>>  {
>>  	bool thread_priv;
>> @@ -124,6 +125,7 @@ ssize_t cpu_show_meltdown(struct device *dev,  
>> struct device_attribute *attr, cha
>>
>>  	return sprintf(buf, "Vulnerable\n");
>>  }
>> +#endif
>>
>>  ssize_t cpu_show_spectre_v1(struct device *dev, struct  
>> device_attribute *attr, char *buf)
>>  {
>> --
>> 2.5.5
>
>