Re: [PATCH v9 30/44] arm64: kasan: Allow enabling in-kernel MTE

[Vincenzo Frascino]

Hi Catalin,

missed this one.

On 11/12/20 9:43 AM, Catalin Marinas wrote:
> On Tue, Nov 10, 2020 at 11:10:27PM +0100, Andrey Konovalov wrote:
>> From: Vincenzo Frascino <vincenzo.frascino@xxxxxxx>
>>
>> Hardware tag-based KASAN relies on Memory Tagging Extension (MTE)
>> feature and requires it to be enabled. MTE supports
>>
>> This patch adds a new mte_init_tags() helper, that enables MTE in
>> Synchronous mode in EL1 and is intended to be called from KASAN runtime
>> during initialization.
> 
> There's no mte_init_tags() in this function.
> 
>> diff --git a/arch/arm64/kernel/mte.c b/arch/arm64/kernel/mte.c
>> index 600b26d65b41..7f477991a6cf 100644
>> --- a/arch/arm64/kernel/mte.c
>> +++ b/arch/arm64/kernel/mte.c
>> @@ -129,6 +129,13 @@ void *mte_set_mem_tag_range(void *addr, size_t size, u8 tag)
>>  	return ptr;
>>  }
>>  
>> +void mte_enable(void)
>> +{
>> +	/* Enable MTE Sync Mode for EL1. */
>> +	sysreg_clear_set(sctlr_el1, SCTLR_ELx_TCF_MASK, SCTLR_ELx_TCF_SYNC);
>> +	isb();
>> +}
> 
> Nitpick: maybe rename this to mte_enable_kernel() since MTE is already
> enabled for user apps.
> 

I will fix this in the next iteration.

-- 
Regards,
Vincenzo