Message-ID: <1393572505.1019.10.camel@wall-e.seibold.net>
Subject: Re: [PATCH v2 1/4] x86: Use the default ABI for the 32-bit vDSO
From: Stefani Seibold <stefani@seibold.net>
To: Andy Lutomirski <luto@amacapital.net>
Cc: X86 ML <x86@kernel.org>, "H. Peter Anvin" <hpa@zytor.com>,
        Greg KH <gregkh@linuxfoundation.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@redhat.com>,
        Andi Kleen <ak@linux.intel.com>,
        Andrea Arcangeli <aarcange@redhat.com>,
        John Stultz <john.stultz@linaro.org>,
        Pavel Emelyanov <xemul@parallels.com>,
        Cyrill Gorcunov <gorcunov@openvz.org>,
        andriy.shevchenko@linux.intel.com, Martin.Runge@rohde-schwarz.com,
        Andreas.Brief@rohde-schwarz.com
Date: Fri, 28 Feb 2014 08:28:25 +0100
In-Reply-To: <2f5d45b67dcd2c4ba58ed7ff13cfcd7a4da977fa.1393545985.git.luto@amacapital.net>
References: <CALCETrW_PHbDzn2S3NyGTSk4yqYjnpJbStCuLc_yBGdfspfFCA@mail.gmail.com>
	 <cover.1393545985.git.luto@amacapital.net>
	 <2f5d45b67dcd2c4ba58ed7ff13cfcd7a4da977fa.1393545985.git.luto@amacapital.net>
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Am Donnerstag, den 27.02.2014, 16:18 -0800 schrieb Andy Lutomirski:
> There's no reason for the vDSO to use a special function call ABI.  Use
> the platform defaults.
> 

The only reason was performance. What is good for the kernel should be
also good for the VDSO. Now all functions inside the VDSO will pass the
arguments by stack.

> Signed-off-by: Andy Lutomirski <luto@amacapital.net>
> ---
>  arch/x86/vdso/Makefile | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/x86/vdso/Makefile b/arch/x86/vdso/Makefile
> index 92daaa6..80584f5 100644
> --- a/arch/x86/vdso/Makefile
> +++ b/arch/x86/vdso/Makefile
> @@ -149,7 +149,7 @@ KBUILD_CFLAGS_32 := $(filter-out -m64,$(KBUILD_CFLAGS))
>  KBUILD_CFLAGS_32 := $(filter-out -mcmodel=kernel,$(KBUILD_CFLAGS_32))
>  KBUILD_CFLAGS_32 := $(filter-out -fno-pic,$(KBUILD_CFLAGS_32))
>  KBUILD_CFLAGS_32 := $(filter-out -mfentry,$(KBUILD_CFLAGS_32))
> -KBUILD_CFLAGS_32 += -m32 -msoft-float -mregparm=3 -freg-struct-return -fpic
> +KBUILD_CFLAGS_32 += -m32 -msoft-float -mregparm=0 -fpic
>  $(vdso32-images:%=$(obj)/%.dbg): KBUILD_CFLAGS = $(KBUILD_CFLAGS_32)
>  
>  $(vdso32-images:%=$(obj)/%.dbg): $(obj)/vdso32-%.so.dbg: FORCE \


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