linux-kernel - Re: [PATCH] i386/audit: stop scribbling on the stack frame

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <544E7A8D.1030909@zytor.com>
Date:	Mon, 27 Oct 2014 10:02:05 -0700
From:	"H. Peter Anvin" <hpa@...or.com>
To:	Eric Paris <eparis@...hat.com>, Richard Guy Briggs <rgb@...hat.com>
CC:	Thomas Gleixner <tglx@...utronix.de>, linux-kernel@...r.kernel.org,
	przanoni@...il.com, mingo@...nel.org, hpa@...ux.intel.com,
	linux-tip-commits@...r.kernel.org, linux-audit@...hat.com
Subject: Re: [PATCH] i386/audit: stop scribbling on the stack frame

On 10/27/2014 06:55 AM, Eric Paris wrote:
> My patch was already committed to the -tip urgent branch.  I believe any
> optimization should be based on that branch, Richard.  If you are trying
> to wrangle every bit of speed out of this, should you
> 
> push %esi;
> push %edi;
> CFI_ADJUST_CFA_OFFSET 8
> call __audit_syscall_entry
> pop;
> pop;
> CFI_ADJUST_CFA_OFFSET -8
> 
> Instead of using the pushl_cfi and popl_cfi macros?
> 
> I wrote my patch to be obviously correct, but agree there are certainly
> some speedups possible.
> 

Uh... not only is that plain wrong (the CFI should be adjusted after
each instruction that changes the stack pointer), but what the heck is
wrong with using the macros?

	-hpa



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