On Wed, 2014-11-12 at 15:12 +0100, Borislav Petkov wrote:
> On Wed, Nov 12, 2014 at 01:38:45PM +, Anvin, H Peter wrote:
> > No, it doesn't. x86 requires 3.4+ at a minimum.
>
> The only test I see is:
>
> #if GCC_VERSION < 30200
> # error Sorry, your compiler is too old - please upgrade it.
>
On Wed, Nov 12, 2014 at 01:38:45PM +, Anvin, H Peter wrote:
> No, it doesn't. x86 requires 3.4+ at a minimum.
The only test I see is:
#if GCC_VERSION < 30200
# error Sorry, your compiler is too old - please upgrade it.
#endif
And even if we do require 3.4, the build fails with 4.1+ so...
-
On Tue, Nov 11, 2014 at 11:43:13AM -0700, Ross Zwisler wrote:
> +static inline void clwb(volatile void *__p)
> +{
> + alternative_io_2(".byte " __stringify(NOP_DS_PREFIX) "; clflush %P0",
> + ".byte 0x66; clflush %P0",
> + X86_FEATURE_CLFLUSHOPT,
> +
el at lists.freedesktop.org; x86 at kernel.org
Subject: Re: [PATCH 3/6] x86: Add support for the clwb instruction
On Tue, Nov 11, 2014 at 11:43:13AM -0700, Ross Zwisler wrote:
> +static inline void clwb(volatile void *__p)
> +{
> + alternative_io_2(".byte " __stringify(NOP_D
On Tue, Nov 11, 2014 at 12:48:52PM -0700, Ross Zwisler wrote:
> Essentially we need one additional byte at the beginning of the clflush so
> that we can flip it into a clflushopt by changing that byte into a 0x66
> prefix. Two options are to either insert a 1 byte ASM_NOP1, or to add a 1
> byte NO
On Tue, Nov 11, 2014 at 12:40:00PM -0700, Ross Zwisler wrote:
> Yep, it's weird, I know. :)
But sure, saving opcode space, makes sense to me.
Btw, I'd still be interested about this:
> +static inline void clwb(volatile void *__p)
> +{
> + alternative_io_2(".byte " __stringify(NOP_DS_PREFIX)
On Tue, Nov 11, 2014 at 08:12:39PM +0100, Borislav Petkov wrote:
> > +".byte 0x66; xsaveopt %P0",
>
> Huh, XSAVEOPT?!? Shouldn't that be CLWB??
Bah, the same opcodes, only 0x66 prefix makes it into CLWB. Could use a
comment I guess.
--
Regards/Gruss,
Boris.
Sent from a
On Tue, Nov 11, 2014 at 11:43:13AM -0700, Ross Zwisler wrote:
> Add support for the new clwb instruction. This instruction was
> announced in the document "Intel Architecture Instruction Set Extensions
> Programming Reference" with reference number 319433-022.
>
> https://software.intel.com/sites
On Tue, 2014-11-11 at 20:46 +0100, Borislav Petkov wrote:
> On Tue, Nov 11, 2014 at 12:40:00PM -0700, Ross Zwisler wrote:
> > Yep, it's weird, I know. :)
>
> But sure, saving opcode space, makes sense to me.
>
> Btw, I'd still be interested about this:
>
> > +static inline void clwb(volatile vo
On Tue, 2014-11-11 at 20:12 +0100, Borislav Petkov wrote:
> On Tue, Nov 11, 2014 at 11:43:13AM -0700, Ross Zwisler wrote:
> > Add support for the new clwb instruction. This instruction was
> > announced in the document "Intel Architecture Instruction Set Extensions
> > Programming Reference" with
On Tue, 2014-11-11 at 20:19 +0100, Borislav Petkov wrote:
> On Tue, Nov 11, 2014 at 08:12:39PM +0100, Borislav Petkov wrote:
> > > + ".byte 0x66; xsaveopt %P0",
> >
> > Huh, XSAVEOPT?!? Shouldn't that be CLWB??
>
> Bah, the same opcodes, only 0x66 prefix makes it into CLWB. Could
Add support for the new clwb instruction. This instruction was
announced in the document "Intel Architecture Instruction Set Extensions
Programming Reference" with reference number 319433-022.
https://software.intel.com/sites/default/files/managed/0d/53/319433-022.pdf
Here are some things of not
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