[U-Boot] [PATCH 1/2] arm: Set TTB XN bit in case DCACHE_OFF for LPAE mode

[Keerthy]

On Friday 28 October 2016 06:42 PM, Tom Rini wrote:
> On Fri, Oct 28, 2016 at 12:01:43PM +0530, Keerthy wrote:
>> While we setup the mmu initially we mark set_section_dcache with
>> DCACHE_OFF flag. In case of non-LPAE mode the DCACHE_OFF macro
>> is rightly defined with TTB_SECT_XN_MASK set so as to mark all the
>> 4GB XN. In case of LPAE mode  XN(Execute-never) bit is not set with
>> DCACHE_OFF. Hence XN bit is not set by default for DCACHE_OFF which
>> keeps all the regions execute okay and this leads to random speculative
>> fetches in random memory regions which was eventually caught by kernel
>> omap-l3-noc driver.
>>
>> Fix this to mark the regions as XN by default.
>>
>> Signed-off-by: Keerthy <j-keerthy at ti.com>
>> ---
>>  arch/arm/include/asm/system.h | 2 +-
>>  arch/arm/lib/cache-cp15.c     | 5 +++++
>>  2 files changed, 6 insertions(+), 1 deletion(-)
>>
>> diff --git a/arch/arm/include/asm/system.h b/arch/arm/include/asm/system.h
>> index b928bd8..2f430ad 100644
>> --- a/arch/arm/include/asm/system.h
>> +++ b/arch/arm/include/asm/system.h
>> @@ -329,7 +329,7 @@ static inline void set_dacr(unsigned int val)
>>
>>  /* options available for data cache on each page */
>>  enum dcache_option {
>> -	DCACHE_OFF = TTB_SECT | TTB_SECT_MAIR(0),
>> +	DCACHE_OFF = TTB_SECT | TTB_SECT_MAIR(0) | TTB_SECT_XN_MASK,
>>  	DCACHE_WRITETHROUGH = TTB_SECT | TTB_SECT_MAIR(1),
>>  	DCACHE_WRITEBACK = TTB_SECT | TTB_SECT_MAIR(2),
>>  	DCACHE_WRITEALLOC = TTB_SECT | TTB_SECT_MAIR(3),
>> diff --git a/arch/arm/lib/cache-cp15.c b/arch/arm/lib/cache-cp15.c
>> index 70e94f0..4d9903e 100644
>> --- a/arch/arm/lib/cache-cp15.c
>> +++ b/arch/arm/lib/cache-cp15.c
>> @@ -71,8 +71,13 @@ void mmu_set_region_dcache_behaviour(phys_addr_t start, size_t size,
>>
>>  	end = ALIGN(start + size, MMU_SECTION_SIZE) >> MMU_SECTION_SHIFT;
>>  	start = start >> MMU_SECTION_SHIFT;
>> +#ifdef CONFIG_ARMV7_LPAE
>> +	debug("%s: start=%pa, size=%zu, option=%llu\n", __func__, &start, size,
>> +	      option);
>> +#else
>>  	debug("%s: start=%pa, size=%zu, option=%d\n", __func__, &start, size,
>>  	      option);
>> +#endif
>
> Does it really make sense to be printing option in decimal rather than
> hex here?

Okay. I will change that to hex and re-post.

>