| Subject | Re: [PATCH 17/37] x86, pkeys: add functions to fetch PKRU | From | Dave Hansen <> | Date | Mon, 30 Nov 2015 07:51:48 -0800 |
| |
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.
|