Re: [PATCH] x86-64 singlestep through sigreturn system call

[Andi Kleen]

On Thu, 15 Jul 2004 14:13:15 -0700
Roland McGrath <roland@xxxxxxxxxx> wrote:

> > Anyways, I don't have any plans to change the 64bit behaviour. gdb will
> > have to live with a few minor inconsistencies as price for faster system
> > calls. 
> 
> My patch doesn't slow anything down beyond one comparison and branch not
> taken in the rt_sigreturn system call.  Does that negligible meaning of
> "faster" really warrant the inconsistent user behavior?

I meant as a general side effect of using SYSRET and not always IRET.
In the later case it would be consistently like i386.

Anyways, even if I applied your patch there would be still inconsistency
because there are several other system calls that use IRET. So I don't
see much advantage in adding a special case just for sigreturn.

-Andi
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