On Jul 1, 2015, at 8:00 PM, Stephen Boyd wrote:
>>
>> #include <asm/barrier.h>
>> +#include <asm/hardware/cp14.h>
>
> That's new.
And no one else is using it either.
>>
>> +
>> +static inline void __dcc_initialize(void)
>> +{
>> + u32 val;
>> +
>> + /* Disable user-space access to DCC */
>> + val = MRC14(0, c0, c1, 0);
>> + val |= 1 << 12; /* DSCR[Comms] */
>> + MCR14(val, 0, c0, c1, 0);
>> +}
>
> Nitpick: We do raw cp14 accesses for other functions in this file, so it
> would be nice to be consistent throughout.
I agree, but I didn't want to expand the scope of this patch beyond what it's
supposed to do.
>>
>> +static inline void __dcc_initialize(void)
>> +{
>> + u32 val;
>> +
>> + /* Disable user-space access to DCC */
>> + asm ("mrs %0, mdscr_el1\n"
>
> shouldn't this be volatile?
Well, I figured it wasn't important exactly why these instructions are
executed, since it just disables user-space. I usually get chewed out by
someone if I add volatile where it's not needed, so I didn't add it this time.
>
>> + " orr %0, %0, #4096\n" /* Set the TDCC bit */
>
> arm64 has some #defines in debug-monitors.h which we should probably
> extend to have this bit as a #define too.
Hmmm, the only thing I see in debug_monitors.h that seems applicable are the
mdscr_write() and mdscr_read() functions, which seem to overlap cp14.h.
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