From: Peter Zijlstra <peterz@infradead.org>
To: Borislav Petkov <bp@alien8.de>
Cc: David Woodhouse <dwmw2@infradead.org>,
Josh Poimboeuf <jpoimboe@redhat.com>,
linux-kernel@vger.kernel.org, Dave Hansen <dave.hansen@intel.com>,
Ashok Raj <ashok.raj@intel.com>,
Thomas Gleixner <tglx@linutronix.de>,
Tim Chen <tim.c.chen@linux.intel.com>,
Andy Lutomirski <luto@kernel.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Greg KH <gregkh@linuxfoundation.org>,
Andrea Arcangeli <aarcange@redhat.com>,
Andi Kleen <ak@linux.intel.com>,
Arjan Van De Ven <arjan.van.de.ven@intel.com>,
Dan Williams <dan.j.williams@intel.com>,
Paolo Bonzini <pbonzini@redhat.com>,
Jun Nakajima <jun.nakajima@intel.com>,
Asit Mallick <asit.k.mallick@intel.com>
Subject: Re: [PATCH v2 07/10] x86/jump_label: Implement arch_static_assert()
Date: Thu, 18 Jan 2018 16:31:31 +0100 [thread overview]
Message-ID: <20180118153131.GG2249@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20180118133322.ep66qnyedjl6qeiv@pd.tnic>
On Thu, Jan 18, 2018 at 02:33:22PM +0100, Borislav Petkov wrote:
> On Tue, Jan 16, 2018 at 03:28:32PM +0100, Peter Zijlstra wrote:
> > Implement the static (branch) assertion. It simply emits the address
> > of the next instruction into a special section which objtool will read
> > and validate against either __jump_table or .altinstructions.
> >
> > Use like:
> >
> > if (static_branch_likely(_key)) {
> > arch_static_assert();
> > /* do stuff */
> > }
> >
> > Or
> >
> > if (static_cpu_has(_feat)) {
> > arch_static_assert();
>
> It looks to me like the asserts can be moved into the macros and the
> assertion checking can happen by default ...?
Right until the point where someone writes:
if (static_cpu_has(_feat) || ponies)
at which point it, rightfully, unconditionally asserts.
Not sure someone does that with static_cpu_has(), but there's
static_branch*() users that do exactly that.
next prev parent reply other threads:[~2018-01-18 15:31 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-16 14:28 [PATCH v2 00/10] objtool validation of static branches and retpoline Peter Zijlstra
2018-01-16 14:28 ` [PATCH v2 01/10] x86: Reindent _static_cpu_has Peter Zijlstra
2018-01-16 15:48 ` Borislav Petkov
2018-01-16 14:28 ` [PATCH v2 02/10] x86: Update _static_cpu_has to use all named variables Peter Zijlstra
2018-01-18 11:21 ` Borislav Petkov
2018-01-18 15:09 ` Peter Zijlstra
2018-01-18 15:24 ` Borislav Petkov
2018-01-16 14:28 ` [PATCH v2 03/10] x86: Add a type field to alt_instr Peter Zijlstra
2018-01-16 22:49 ` Josh Poimboeuf
2018-01-16 22:53 ` Borislav Petkov
2018-01-16 23:06 ` Josh Poimboeuf
2018-01-18 11:32 ` Borislav Petkov
2018-01-16 14:28 ` [PATCH v2 04/10] objtool: Implement base jump_assert support Peter Zijlstra
2018-01-16 14:28 ` [PATCH v2 05/10] x86: Annotate static_cpu_has alternative Peter Zijlstra
2018-01-18 13:15 ` Borislav Petkov
2018-01-16 14:28 ` [PATCH v2 06/10] objtool: Implement jump_assert for _static_cpu_has() Peter Zijlstra
2018-01-16 23:02 ` Josh Poimboeuf
2018-01-17 9:19 ` Peter Zijlstra
2018-01-17 14:27 ` Josh Poimboeuf
2018-01-17 14:30 ` Josh Poimboeuf
2018-01-17 16:30 ` Peter Zijlstra
2018-01-16 14:28 ` [PATCH v2 07/10] x86/jump_label: Implement arch_static_assert() Peter Zijlstra
2018-01-18 13:33 ` Borislav Petkov
2018-01-18 15:31 ` Peter Zijlstra [this message]
2018-01-16 14:28 ` [PATCH v2 08/10] objtool: Add retpoline validation Peter Zijlstra
2018-01-16 14:28 ` [PATCH v2 09/10] x86: Annotate dynamic jump in head_64.S Peter Zijlstra
2018-01-16 14:28 ` [PATCH v2 10/10] objtool: More complex static jump implementation Peter Zijlstra
2018-01-16 15:20 ` Peter Zijlstra
2018-01-17 3:05 ` Josh Poimboeuf
2018-01-17 8:18 ` Peter Zijlstra
2018-01-16 19:49 ` [PATCH v2 11/10] objtool: Even more complex static block checks Peter Zijlstra
2018-01-17 3:12 ` Josh Poimboeuf
2018-01-17 8:13 ` Peter Zijlstra
2018-01-17 14:13 ` Josh Poimboeuf
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