From: Stefani Seibold <stefani@seibold.net>
To: "H. Peter Anvin" <hpa@zytor.com>
Cc: linux-kernel@vger.kernel.org, x86@kernel.org, tglx@linutronix.de,
mingo@redhat.com, ak@linux.intel.com, aarcange@redhat.com,
john.stultz@linaro.org, luto@amacapital.net, xemul@parallels.com,
gorcunov@openvz.org, andriy.shevchenko@linux.intel.com
Subject: Re: [PATCH 6/6] Add 32 bit VDSO support for 32 and 64 bit kernels
Date: Tue, 18 Dec 2012 17:52:38 +0100 [thread overview]
Message-ID: <1355849558.26967.24.camel@wall-e> (raw)
In-Reply-To: <50D09733.3080502@zytor.com>
Am Dienstag, den 18.12.2012, 08:17 -0800 schrieb H. Peter Anvin:
> On 12/18/2012 01:40 AM, stefani@seibold.net wrote:
> > From: Stefani Seibold <stefani@seibold.net>
> >
> > This patch adds support for 32 bit VDSO.
> >
> > For 32 bit programs running on a 32 bit kernel, the same mechanism is
> > used as for 64 bit programs running on a 64 bit kernel.
> >
> > For 32 bit programs running under a 64 bit IA32_EMULATION, it is a
> > little bit more tricky. In this case the VVAR and HPET will be mapped
> > into the 32 bit address space, by cutting of the upper 32 bit. So the
> > address for this will not changed in the view of the 32 bit VDSO. The
> > HPET will be mapped in this case at 0xff5fe000 and the VVAR at 0xff5ff000.
> >
> > The transformation between the in 64 bit kernel representation and the 32 bit
> > abi will be also provided.
> >
> > So we have one VDSO Source for all.
> >
>
> You seem to once again have disregarded the request to make the vvar and
> hpet part of the vdso address space proper. If this is not possible or
> highly impractical, please extend a technical motivation why that is so,
> rather than simply ignoring it.
>
Pardon, i never disregarded nor i have agreed that this is going to be a
part of the VDSO. I currently have also no idea how to do this and i see
no need at the moment to do this revamp. The 64 bit VDSO lives since
more than 6 years with this kind of implementation.
You asked me to do the VDSO 32 bit stuff for the IA32_EMULATION, before
it is ready for inclusion into the kernel. Thats exactly what i did. I
spend the whole weekend of my spare time to do this implementation. Now
we have them all.
The patch works perfectly, all issues are solved:
- Calling conventions
- ABI transformations
- System call gateway for X86 32 bit
- Mapping of the FIXMAP and HPET into the lower 32 bit address space for
IA32_EMULATION
- Support for 32 bit programs in 32 kernel and 64 bit kernel
- One VDSO source for all
If you prefer an other solutions, its okay. There are many ways to code
things. But for now i think it is a good step ahead. That is what i
currently can provide.
- Stefani
next prev parent reply other threads:[~2012-12-18 16:53 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-12-18 9:40 [PATCH 0/6] Add 32 bit VDSO time function support stefani
2012-12-18 9:40 ` [PATCH 1/6] Move out seqcount from seqlock.h stefani
2012-12-18 9:40 ` [PATCH 2/6] Make vsyscall_gtod_data handling x86 generic stefani
2012-12-18 9:40 ` [PATCH 3/6] Make vsyscall_gtod_data compatible with 32 bit VDSO stefani
2012-12-18 9:40 ` [PATCH 4/6] Add new base function _install_special_mapping() to mmap.c stefani
2012-12-18 9:40 ` [PATCH 5/6] Cleanup header files to build a proper 32 bit VDSO stefani
2012-12-18 9:40 ` [PATCH 6/6] Add 32 bit VDSO support for 32 and 64 bit kernels stefani
2012-12-18 16:17 ` H. Peter Anvin
2012-12-18 16:52 ` Stefani Seibold [this message]
2012-12-18 18:44 ` H. Peter Anvin
2012-12-18 20:32 ` Stefani Seibold
2012-12-18 20:37 ` Andy Lutomirski
2012-12-18 22:24 ` H. Peter Anvin
2012-12-20 7:41 ` Stefani Seibold
2012-12-20 16:17 ` H. Peter Anvin
2012-12-20 17:53 ` Stefani Seibold
2012-12-20 18:21 ` H. Peter Anvin
2012-12-20 18:23 ` H.J. Lu
2012-12-20 18:35 ` Roland McGrath
2012-12-20 18:40 ` H. Peter Anvin
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