linux-kernel - Re: [PATCH RFC V3 6/9] x86/entry: Pass irqentry_state

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: <871rhtapir.fsf@nanos.tec.linutronix.de>
Date:   Mon, 19 Oct 2020 23:12:44 +0200
From:   Thomas Gleixner <tglx@...utronix.de>
To:     Ira Weiny <ira.weiny@...el.com>
Cc:     Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        Andy Lutomirski <luto@...nel.org>, x86@...nel.org,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        Dan Williams <dan.j.williams@...el.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Fenghua Yu <fenghua.yu@...el.com>, linux-doc@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-nvdimm@...ts.01.org,
        linux-fsdevel@...r.kernel.org, linux-mm@...ck.org,
        linux-kselftest@...r.kernel.org
Subject: Re: [PATCH RFC V3 6/9] x86/entry: Pass irqentry_state_t by reference

On Mon, Oct 19 2020 at 13:26, Ira Weiny wrote:
> On Mon, Oct 19, 2020 at 11:32:50AM +0200, Thomas Gleixner wrote:
> Sorry, let me clarify.  After this patch we have.
>
> typedef union irqentry_state {
> 	bool	exit_rcu;
> 	bool	lockdep;
> } irqentry_state_t;
>
> Which reflects the mutual exclusion of the 2 variables.

Huch? From the patch I gave you:

 #ifndef irqentry_state
 typedef struct irqentry_state {
 	bool    exit_rcu;
+       bool    lockdep;
 } irqentry_state_t;
 #endif

How is that a union?

> But then when the pkrs stuff is added the union changes back to a structure and
> looks like this.

So you want:

  1) Move stuff to struct irqentry_state (my patch)

  2) Change it to a union and pass it as pointer at the same time

  3) Change it back to struct to add PKRS

> Is that clear?

What's clear is that the above is nonsense. We can just do

 #ifndef irqentry_state
 typedef struct irqentry_state {
 	union {
         	bool    exit_rcu;
                bool    lockdep;
        };        
 } irqentry_state_t;
 #endif

right in the patch which I gave you. Because that actually makes sense.

Thanks,

        tglx