From: Will Deacon <will@kernel.org>
To: Nick Desaulniers <ndesaulniers@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>,
Vincenzo Frascino <vincenzo.frascino@arm.com>,
Linux ARM <linux-arm-kernel@lists.infradead.org>,
LKML <linux-kernel@vger.kernel.org>,
Ard Biesheuvel <ard.biesheuvel@linaro.org>,
Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [PATCH v3 1/5] arm64: vdso32: Introduce COMPAT_CC_IS_GCC
Date: Tue, 1 Oct 2019 18:07:53 +0100 [thread overview]
Message-ID: <20191001170753.sqmfqt7zf33jgzns@willie-the-truck> (raw)
In-Reply-To: <CAKwvOd=+-PEQXOZBG6rprWdOzHfcQq9ojkGo+Q28vfC4AU=Hwg@mail.gmail.com>
On Tue, Oct 01, 2019 at 09:59:43AM -0700, Nick Desaulniers wrote:
> On Tue, Oct 1, 2019 at 9:47 AM Will Deacon <will@kernel.org> wrote:
> >
> > On Tue, Oct 01, 2019 at 04:30:56PM +0100, Catalin Marinas wrote:
> > > In the long run, I wouldn't mandate CROSS_COMPILE_COMPAT to always be
> > > set for the compat vDSO since with clang we could use the same compiler
> > > binary for both native and compat (with different flags). That's once we
> > > cleaned up the headers.
> >
> > But we'll still need it even with clang so that the relevant triple can be
> > passed to the --target option. The top-level Makefile already does this:
> >
> > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Makefile#n544
>
> That's not pulling the cross compiler out of a *config* (as this patch
> is proposing); rather from an env var.
CROSS_COMPILE_COMPAT is the environment variable, right? If not, then I have
my terminology mixed up.
> > so I think we should do the same thing for the compat vdso as well, which
> > would allow us to remove this complexity by requiring that
> > CROSS_COMPILE_COMPAT identifies the cross-compiler to use in exactly the
> > same way as CROSS_COMPILE does.
> >
> > Am I missing something here?
>
> I think the second paragraph you wrote shows we're all in agreement,
> but I suspect you may be conflating *how* the toplevel Makefile knows
> we're doing a cross compile. It doesn't read a config, this patch
> would make it so a cross compiler is specified via config, Catalin
> asked "please no," I agree with Catalin (and I suspect you do too).
Yes, I'm saying let's have an environment variable only and drop the
CONFIG stuff completely. I think this means that the environment variable
must always be specified if you want the compat vDSO, but I don't see that
as a problem.
Will
WARNING: multiple messages have this Message-ID (diff)
From: Will Deacon <will@kernel.org>
To: Nick Desaulniers <ndesaulniers@google.com>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>,
Catalin Marinas <catalin.marinas@arm.com>,
LKML <linux-kernel@vger.kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Vincenzo Frascino <vincenzo.frascino@arm.com>,
Linux ARM <linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH v3 1/5] arm64: vdso32: Introduce COMPAT_CC_IS_GCC
Date: Tue, 1 Oct 2019 18:07:53 +0100 [thread overview]
Message-ID: <20191001170753.sqmfqt7zf33jgzns@willie-the-truck> (raw)
In-Reply-To: <CAKwvOd=+-PEQXOZBG6rprWdOzHfcQq9ojkGo+Q28vfC4AU=Hwg@mail.gmail.com>
On Tue, Oct 01, 2019 at 09:59:43AM -0700, Nick Desaulniers wrote:
> On Tue, Oct 1, 2019 at 9:47 AM Will Deacon <will@kernel.org> wrote:
> >
> > On Tue, Oct 01, 2019 at 04:30:56PM +0100, Catalin Marinas wrote:
> > > In the long run, I wouldn't mandate CROSS_COMPILE_COMPAT to always be
> > > set for the compat vDSO since with clang we could use the same compiler
> > > binary for both native and compat (with different flags). That's once we
> > > cleaned up the headers.
> >
> > But we'll still need it even with clang so that the relevant triple can be
> > passed to the --target option. The top-level Makefile already does this:
> >
> > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Makefile#n544
>
> That's not pulling the cross compiler out of a *config* (as this patch
> is proposing); rather from an env var.
CROSS_COMPILE_COMPAT is the environment variable, right? If not, then I have
my terminology mixed up.
> > so I think we should do the same thing for the compat vdso as well, which
> > would allow us to remove this complexity by requiring that
> > CROSS_COMPILE_COMPAT identifies the cross-compiler to use in exactly the
> > same way as CROSS_COMPILE does.
> >
> > Am I missing something here?
>
> I think the second paragraph you wrote shows we're all in agreement,
> but I suspect you may be conflating *how* the toplevel Makefile knows
> we're doing a cross compile. It doesn't read a config, this patch
> would make it so a cross compiler is specified via config, Catalin
> asked "please no," I agree with Catalin (and I suspect you do too).
Yes, I'm saying let's have an environment variable only and drop the
CONFIG stuff completely. I think this means that the environment variable
must always be specified if you want the compat vDSO, but I don't see that
as a problem.
Will
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next prev parent reply other threads:[~2019-10-01 17:08 UTC|newest]
Thread overview: 127+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-20 14:27 Problems with arm64 compat vdso Will Deacon
2019-09-20 16:33 ` Vincenzo Frascino
2019-09-23 16:41 ` Ard Biesheuvel
2019-09-24 12:11 ` Vincenzo Frascino
2019-09-24 18:06 ` Nick Desaulniers
2019-09-24 20:42 ` Vincenzo Frascino
2019-09-25 15:58 ` Ard Biesheuvel
2019-09-26 6:03 ` [PATCH 0/4] arm64: vdso32: Address various issues Vincenzo Frascino
2019-09-26 6:03 ` Vincenzo Frascino
2019-09-26 6:03 ` [PATCH 1/4] arm64: vdso32: Introduce COMPAT_CC_IS_GCC Vincenzo Frascino
2019-09-26 6:03 ` Vincenzo Frascino
2019-09-26 8:06 ` Catalin Marinas
2019-09-26 8:06 ` Catalin Marinas
2019-09-26 10:56 ` Vincenzo Frascino
2019-09-26 10:56 ` Vincenzo Frascino
2019-09-26 11:02 ` Vincenzo Frascino
2019-09-26 11:02 ` Vincenzo Frascino
2019-09-26 15:23 ` Catalin Marinas
2019-09-26 15:23 ` Catalin Marinas
2019-09-26 12:22 ` Vincenzo Frascino
2019-09-26 12:22 ` Vincenzo Frascino
2019-09-26 15:17 ` Catalin Marinas
2019-09-26 15:17 ` Catalin Marinas
2019-09-26 20:17 ` Vincenzo Frascino
2019-09-26 20:17 ` Vincenzo Frascino
2019-09-26 6:03 ` [PATCH 2/4] arm64: vdso32: Detect binutils support for dmb ishld Vincenzo Frascino
2019-09-26 6:03 ` Vincenzo Frascino
2019-09-26 8:30 ` Catalin Marinas
2019-09-26 8:30 ` Catalin Marinas
2019-09-26 10:59 ` Vincenzo Frascino
2019-09-26 10:59 ` Vincenzo Frascino
2019-09-26 6:03 ` [PATCH 3/4] arm64: vdso32: Fix compilation warning Vincenzo Frascino
2019-09-26 6:03 ` Vincenzo Frascino
2019-09-26 8:32 ` Catalin Marinas
2019-09-26 8:32 ` Catalin Marinas
2019-09-26 11:03 ` Vincenzo Frascino
2019-09-26 11:03 ` Vincenzo Frascino
2019-09-26 6:03 ` [PATCH 4/4] arm64: Remove gettimeofday.S Vincenzo Frascino
2019-09-26 6:03 ` Vincenzo Frascino
2019-09-26 8:34 ` Catalin Marinas
2019-09-26 8:34 ` Catalin Marinas
2019-09-26 13:38 ` [PATCH v2 0/4] arm64: vdso32: Address various issues Vincenzo Frascino
2019-09-26 13:38 ` Vincenzo Frascino
2019-09-26 13:38 ` [PATCH v2 1/4] arm64: vdso32: Introduce COMPAT_CC_IS_GCC Vincenzo Frascino
2019-09-26 13:38 ` Vincenzo Frascino
2019-09-26 15:13 ` Catalin Marinas
2019-09-26 15:13 ` Catalin Marinas
2019-09-26 13:38 ` [PATCH v2 2/4] arm64: vdso32: Detect binutils support for dmb ishld Vincenzo Frascino
2019-09-26 13:38 ` Vincenzo Frascino
2019-09-26 14:26 ` Catalin Marinas
2019-09-26 14:26 ` Catalin Marinas
2019-09-26 20:19 ` Vincenzo Frascino
2019-09-26 20:19 ` Vincenzo Frascino
2019-09-26 15:59 ` Catalin Marinas
2019-09-26 15:59 ` Catalin Marinas
2019-09-26 21:17 ` Vincenzo Frascino
2019-09-26 21:17 ` Vincenzo Frascino
2019-09-26 16:23 ` Nick Desaulniers
2019-09-26 16:23 ` Nick Desaulniers
2019-09-26 13:38 ` [PATCH v2 3/4] arm64: vdso32: Fix compilation warning Vincenzo Frascino
2019-09-26 13:38 ` Vincenzo Frascino
2019-09-26 15:22 ` Catalin Marinas
2019-09-26 15:22 ` Catalin Marinas
2019-09-26 13:38 ` [PATCH v2 4/4] arm64: Remove gettimeofday.S Vincenzo Frascino
2019-09-26 13:38 ` Vincenzo Frascino
2019-09-26 15:31 ` [PATCH v2 0/4] arm64: vdso32: Address various issues Catalin Marinas
2019-09-26 15:31 ` Catalin Marinas
2019-09-26 20:29 ` Vincenzo Frascino
2019-09-26 20:29 ` Vincenzo Frascino
2019-09-26 21:43 ` [PATCH v3 0/5]arm64: " Vincenzo Frascino
2019-09-26 21:43 ` Vincenzo Frascino
2019-09-26 21:43 ` [PATCH v3 1/5] arm64: vdso32: Introduce COMPAT_CC_IS_GCC Vincenzo Frascino
2019-09-26 21:43 ` Vincenzo Frascino
2019-09-27 9:24 ` Catalin Marinas
2019-09-27 9:24 ` Catalin Marinas
2019-10-01 13:14 ` Will Deacon
2019-10-01 13:14 ` Will Deacon
2019-10-01 13:27 ` Catalin Marinas
2019-10-01 13:27 ` Catalin Marinas
2019-10-01 14:20 ` Vincenzo Frascino
2019-10-01 14:20 ` Vincenzo Frascino
2019-10-01 14:20 ` Will Deacon
2019-10-01 14:20 ` Will Deacon
2019-10-01 14:37 ` Vincenzo Frascino
2019-10-01 14:37 ` Vincenzo Frascino
2019-10-01 14:43 ` Will Deacon
2019-10-01 14:43 ` Will Deacon
2019-10-01 14:59 ` Vincenzo Frascino
2019-10-01 14:59 ` Vincenzo Frascino
2019-10-01 15:30 ` Catalin Marinas
2019-10-01 15:30 ` Catalin Marinas
2019-10-01 16:46 ` Will Deacon
2019-10-01 16:46 ` Will Deacon
2019-10-01 16:59 ` Nick Desaulniers
2019-10-01 16:59 ` Nick Desaulniers
2019-10-01 17:07 ` Will Deacon [this message]
2019-10-01 17:07 ` Will Deacon
2019-10-01 17:12 ` Nick Desaulniers
2019-10-01 17:12 ` Nick Desaulniers
2019-10-01 17:14 ` Will Deacon
2019-10-01 17:14 ` Will Deacon
2019-09-26 21:43 ` [PATCH v3 2/5] arm64: vdso32: Detect binutils support for dmb ishld Vincenzo Frascino
2019-09-26 21:43 ` Vincenzo Frascino
2019-09-27 9:25 ` Catalin Marinas
2019-09-27 9:25 ` Catalin Marinas
2019-10-01 13:26 ` Will Deacon
2019-10-01 13:26 ` Will Deacon
2019-10-01 14:23 ` Vincenzo Frascino
2019-10-01 14:23 ` Vincenzo Frascino
2019-09-26 21:43 ` [PATCH v3 3/5] arm64: vdso32: Fix compilation warning Vincenzo Frascino
2019-09-26 21:43 ` Vincenzo Frascino
2019-09-27 9:26 ` Catalin Marinas
2019-09-27 9:26 ` Catalin Marinas
2019-10-01 13:21 ` Will Deacon
2019-10-01 13:21 ` Will Deacon
2019-10-01 14:41 ` Vincenzo Frascino
2019-10-01 14:41 ` Vincenzo Frascino
2019-09-26 21:43 ` [PATCH v3 4/5] arm64: Remove gettimeofday.S Vincenzo Frascino
2019-09-26 21:43 ` Vincenzo Frascino
2019-09-26 21:43 ` [PATCH v3 5/5] arm64: vdso32: Remove jump label config option in Makefile Vincenzo Frascino
2019-09-26 21:43 ` Vincenzo Frascino
2019-09-27 9:27 ` Catalin Marinas
2019-09-27 9:27 ` Catalin Marinas
2019-09-27 10:46 ` [PATCH v3 0/5]arm64: vdso32: Address various issues Catalin Marinas
2019-09-27 10:46 ` Catalin Marinas
2019-10-01 13:27 ` Will Deacon
2019-10-01 13:27 ` Will Deacon
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