Re: [PATCH] basic perf support for sparc

[Ingo Molnar <mingo@elte.hu>]

* David Miller <davem@davemloft.net> wrote:

> From: Jens Axboe <jens.axboe@oracle.com>
> Date: Wed, 29 Jul 2009 13:25:10 +0200
> 
> > -#define NR_SYSCALLS		327
> > +#define NR_SYSCALLS		328
> 
> When you increase this value, you have to add entries to all of 
> the syscall tables.  The syscall dispatch checks against this as a 
> limit, so if you don't explicitly add an entry to all the tables, 
> it's possible to deref garbage past the end of the table and try 
> to jump to it as a syscall.
> 
> And if you somehow arrange for adding a compat syscall entry here 
> for this, and build the perf tools 32-bit, you can forego all of 
> these rediculious issues with trying to get a 64-bit BFD library.  
> If the perf tools are written portably and use types like u64 etc. 
> for holding addresses and similar things, this should not be an 
> issue.
> 
> The 32-bit sparc BFD library has full support for all the 64-bit 
> binary formats and whatnot.

That would work too. On x86 perf works all across the compatibility 
spectrum, and we do use strict u32/u64 typing and ABIs.

Note that we'll also solve (remove) the binutils-devel dependency, 
it creates a way too large set of external build constraints for 
perf. But in any case both 32-bit and 64-bit perf should work just 
fine.

	Ingo