Re: [tip:x86/asm] x86-64, copy_user: Remove zero byte check beforecopy user buffer.

[Linus Torvalds]

On Wed, Nov 20, 2013 at 12:36 PM, H. Peter Anvin <hpa@xxxxxxxxx> wrote:
>
> That being said, "lea (%rdx,%rcx,8),%ecx" (leal, as opposed to leaq) is
> a perfectly legitimate instruction and actually one byte shorter.  The
> big question is if some broken version of gas will choke on it.

At least gcc-4.8.2 generates that instruction (try multiplying an
integer value by 9), so I guess gas will be happy. Except gcc uses
"leal", so to be safe..

              Linus
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/