linux-kernel - Re: [RFCv2 03/10] x86: Introduce userspace API to handle per-thread features

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: <543eb3ff98f624c6cfa1d450ac3e9ae8934c7c38.camel@intel.com>
Date:   Fri, 13 May 2022 23:50:03 +0000
From:   "Edgecombe, Rick P" <rick.p.edgecombe@...el.com>
To:     "kirill.shutemov@...ux.intel.com" <kirill.shutemov@...ux.intel.com>
CC:     "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "peterz@...radead.org" <peterz@...radead.org>,
        "hjl.tools@...il.com" <hjl.tools@...il.com>,
        "linux-mm@...ck.org" <linux-mm@...ck.org>,
        "dave.hansen@...ux.intel.com" <dave.hansen@...ux.intel.com>,
        "aryabinin@...tuozzo.com" <aryabinin@...tuozzo.com>,
        "dvyukov@...gle.com" <dvyukov@...gle.com>,
        "x86@...nel.org" <x86@...nel.org>,
        "ak@...ux.intel.com" <ak@...ux.intel.com>,
        "Lutomirski, Andy" <luto@...nel.org>,
        "glider@...gle.com" <glider@...gle.com>
Subject: Re: [RFCv2 03/10] x86: Introduce userspace API to handle per-thread
 features

On Sat, 2022-05-14 at 02:09 +0300, Kirill A. Shutemov wrote:
> On Fri, May 13, 2022 at 05:34:12PM +0000, Edgecombe, Rick P wrote:
> > On Fri, 2022-05-13 at 16:09 +0200, Alexander Potapenko wrote:
> > > > +
> > > > +       /* Handle ARCH_THREAD_FEATURE_ENABLE */
> > > > +
> > > > +       task->thread.features |= features;
> > > > +out:
> > > > +       return task->thread.features;
> > > 
> > > Isn't arch_prctl() supposed to return 0 on success?
> > 
> > Hmm, good point. Maybe we'll need a struct to pass info in and out.
> 
> But values >0 are unused. I don't see why can't we use them.

Hmm, I don't know what it would break since it is a new "code"
argument. But the man page says:
"On success, arch_prctl() returns 0; on error, -1 is returned, and
errno is set to indicate the error."

So just change the man pages?
"On success, arch_prctl() returns positive values; on error, -1 is
returned, and errno is set to indicate the error."