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SubjectRe: [PATCH] x86/vdso: fix lsl operand order
On Sat, Sep 1, 2018 at 1:14 PM, Samuel Neves <sneves@dei.uc.pt> wrote:
> In the __getcpu function, lsl was using the wrong target
> and destination registers. Luckily, the compiler tends to
> choose %eax for both variables, so it has been working
> so far.
>
> Cc: x86@kernel.org
> Cc: stable@vger.kernel.org
> Signed-off-by: Samuel Neves <sneves@dei.uc.pt>

Acked-by: Andy Lutomirski <luto@kernel.org>
Fixes: a582c540ac1b ("x86/vdso: Use RDPID in preference to LSL when available")

Whoops! I even wrote a selftest just for the offending commit, but,
of course, the selftest passes :( I tested this by giving gcc some
gentle encouragement to allocate different registers, and the existing
code is indeed wrong and the fix indeed fixes it.

--Andy

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