linux-kernel - Re: Kernel broken on processors without performance counters

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: <20150723170811.GJ25159@twins.programming.kicks-ass.net>
Date:	Thu, 23 Jul 2015 19:08:11 +0200
From:	Peter Zijlstra <peterz@...radead.org>
To:	Steven Rostedt <rostedt@...dmis.org>
Cc:	Jason Baron <jasonbaron0@...il.com>,
	Borislav Petkov <bp@...en8.de>,
	Andy Lutomirski <luto@...capital.net>,
	Thomas Gleixner <tglx@...utronix.de>,
	Mikulas Patocka <mpatocka@...hat.com>,
	Paul Mackerras <paulus@...ba.org>,
	Arnaldo Carvalho de Melo <acme@...nel.org>,
	Kees Cook <keescook@...omium.org>,
	Andrea Arcangeli <aarcange@...hat.com>,
	Vince Weaver <vince@...ter.net>,
	"hillf.zj" <hillf.zj@...baba-inc.com>,
	Valdis Kletnieks <Valdis.Kletnieks@...edu>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: Kernel broken on processors without performance counters

On Thu, Jul 23, 2015 at 11:34:50AM -0400, Steven Rostedt wrote:
> On Thu, 23 Jul 2015 12:42:15 +0200
> Peter Zijlstra <peterz@...radead.org> wrote:
> 
> > static __always_inline bool arch_static_branch_jump(struct static_key *key, bool inv)
> > {
> > 	if (!inv) {
> > 		asm_volatile_goto("1:"
> > 			"jmp %l[l_yes]\n\t"
> 
> And what happens when this gets converted to a two byte jump?
> 

That would be bad, how can we force it to emit 5 bytes?
--
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/