On 11/27/2015 01:51 AM, Thomas Gleixner wrote:
> On Mon, 16 Nov 2015, Dave Hansen wrote:
>> +#ifdef CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS
>> +static inline u32 __read_pkru(void)
>> +{
>> + unsigned int eax, edx;
>> + unsigned int ecx = 0;
>> + unsigned int pkru;
>> +
>> + asm volatile(".byte 0x0f,0x01,0xee\n\t"
>> + : "=a" (eax), "=d" (edx)
>> + : "c" (ecx));
>> + pkru = eax;
>> + return pkru;
>
> Wouldn't a simple 'return eax;' be sufficient?
Yes. I wanted to make it clear that EAX specifically was where the data
we want was ending up. But, I guess the "=a" does that equally well.
I'll fix it up.
Also, looking at this, it also deserves a mention that this is the
"rdpkru" instruction. Otherwise, it's hard to figure out what
instruction this is.
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