Re: [tip: x86/pasid] x86/asm: Carve out a generic movdir64b() helper for general usage

From: Borislav Petkov
Date: Wed Oct 07 2020 - 17:13:39 EST


On Wed, Oct 07, 2020 at 07:08:35PM +0200, Peter Zijlstra wrote:
> (%rdx), %rax, surely?

Right, later. Already tagged the branch so that Vinod can base stuff ontop.

> Also, that's a horrible convention, but I suppose (%rdx), (%rax) was
> out?

See the end of this mail:

https://lkml.kernel.org/r/alpine.LSU.2.20.2009241356020.20802@xxxxxxxxxxxxx

> Can we pretty please get a binutils version that knows about this
> instruction, such that we know when we can get rid of the silly .byte
> encoded mess?

It looks like support for this insn got introduced in this binutils commit:

c0a30a9f0ab4 ("Enable Intel MOVDIRI, MOVDIR64B instructions")

So I guess from 2.31 onwards:

$ git tag --contains c0a30a9f0ab48
binutils-2_31
binutils-2_31_1
binutils-2_32
binutils-2_33
binutils-2_33_1
binutils-2_34
binutils-2_35
binutils-2_35_1
gdb-8.2-release
gdb-8.2.1-release
gdb-8.3-release
gdb-8.3.1-release
gdb-9.1-release
gdb-9.2-release
...

--
Regards/Gruss,
Boris.

https://people.kernel.org/tglx/notes-about-netiquette