From: Will Deacon <will@kernel.org>
To: Catalin Marinas <catalin.marinas@arm.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, ard.biesheuvel@linaro.org,
ndesaulniers@google.com, tglx@linutronix.de
Subject: Re: [PATCH v3 1/5] arm64: vdso32: Introduce COMPAT_CC_IS_GCC
Date: Tue, 1 Oct 2019 17:46:58 +0100 [thread overview]
Message-ID: <20191001164657.l2wz3ghq6icm3lim@willie-the-truck> (raw)
In-Reply-To: <20191001153056.GO41399@arrakis.emea.arm.com>
On Tue, Oct 01, 2019 at 04:30:56PM +0100, Catalin Marinas wrote:
> On Tue, Oct 01, 2019 at 03:43:54PM +0100, Will Deacon wrote:
> > > >>>> On Thu, Sep 26, 2019 at 10:43:38PM +0100, Vincenzo Frascino wrote:
> > > >>>>> +config COMPATCC_IS_ARM_GCC
> > > >>>>> + def_bool $(success,$(COMPATCC) --version | head -n 1 | grep -q "arm-.*-gcc")
> [...]
> > My point was that we don't attempt to sanitise the compiler passed via
> > CROSS_COMPILE, so I don't think we should do anything special for COMPATCC
> > either.
>
> What I really want from kbuild with this patch is:
>
> 1. Not to warn me that I don't have a CROSS_COMPILE_COMPAT set
>
> 2. Not to give me a compilation error if the makefile made up a COMPATCC
> that doesn't work
>
> Since we dropped the Kconfig option for the compat gcc prefix (which I
> didn't like anyway), COMPATCC is now initialised to
> (CROSS_COMPILE_COMPAT)gcc. This means that it is valid compiler (and
> it's an aarch64 compiler on my machine). The COMPATCC_IS_ARM_GCC
> silently disables the compat vDSO for this case rather than giving me a
> build error if we don't have such checks.
>
> 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
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?
Will
WARNING: multiple messages have this Message-ID (diff)
From: Will Deacon <will@kernel.org>
To: Catalin Marinas <catalin.marinas@arm.com>
Cc: ard.biesheuvel@linaro.org, ndesaulniers@google.com,
linux-kernel@vger.kernel.org, tglx@linutronix.de,
Vincenzo Frascino <vincenzo.frascino@arm.com>,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v3 1/5] arm64: vdso32: Introduce COMPAT_CC_IS_GCC
Date: Tue, 1 Oct 2019 17:46:58 +0100 [thread overview]
Message-ID: <20191001164657.l2wz3ghq6icm3lim@willie-the-truck> (raw)
In-Reply-To: <20191001153056.GO41399@arrakis.emea.arm.com>
On Tue, Oct 01, 2019 at 04:30:56PM +0100, Catalin Marinas wrote:
> On Tue, Oct 01, 2019 at 03:43:54PM +0100, Will Deacon wrote:
> > > >>>> On Thu, Sep 26, 2019 at 10:43:38PM +0100, Vincenzo Frascino wrote:
> > > >>>>> +config COMPATCC_IS_ARM_GCC
> > > >>>>> + def_bool $(success,$(COMPATCC) --version | head -n 1 | grep -q "arm-.*-gcc")
> [...]
> > My point was that we don't attempt to sanitise the compiler passed via
> > CROSS_COMPILE, so I don't think we should do anything special for COMPATCC
> > either.
>
> What I really want from kbuild with this patch is:
>
> 1. Not to warn me that I don't have a CROSS_COMPILE_COMPAT set
>
> 2. Not to give me a compilation error if the makefile made up a COMPATCC
> that doesn't work
>
> Since we dropped the Kconfig option for the compat gcc prefix (which I
> didn't like anyway), COMPATCC is now initialised to
> (CROSS_COMPILE_COMPAT)gcc. This means that it is valid compiler (and
> it's an aarch64 compiler on my machine). The COMPATCC_IS_ARM_GCC
> silently disables the compat vDSO for this case rather than giving me a
> build error if we don't have such checks.
>
> 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
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?
Will
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next prev parent reply other threads:[~2019-10-01 16:47 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 [this message]
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
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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