Re: [PATCH] libitm: Add custom HTM fast path for RTM on x86_64.

[Torvald Riegel <triegel at redhat dot com>]

On Thu, 2013-08-22 at 12:05 -0700, Richard Henderson wrote:
> On 08/22/2013 11:39 AM, Torvald Riegel wrote:
> > +	/* Store edi for future HTM fast path retries.  We use a stack slot
> > +	   lower than the jmpbuf so that the jmpbuf's rip field will overlap
> > +	   with the proper return address on the stack.  */
> > +	movl	%edi, -64(%rsp)
> 
> You havn't allocated the stack frame here, and you're storing
> outside the redzone.  This is invalid.
> 
> Two possibilities:
> 
>  (1) always allocate the stack frame on entry to
>      the function (adds two register additions to
>      the htm fast path -- in the noise i'd think)
> 
>  (2) store the edi value in the non-htm path, with
>      the pr_HTMRetryableAbort bit or'd in.  (adds an
>      extra store to the non-htm path; probably noise).
>      You'd want to mask out that bit when you reload it.

Oops.  Picked fix (2).  Better now?

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