linux-kernel - Re: [PATCH 30/30] x32: Add x32 VDSO support

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Message-ID: <CAObL_7Hy8Y0PWrcZdRSGRcEt+aoma7ax4XU44f-gdHEGoWBzTg@mail.gmail.com>
Date:	Tue, 21 Feb 2012 08:52:20 -0800
From:	Andrew Lutomirski <luto@....edu>
To:	"H. Peter Anvin" <hpa@...or.com>
Cc:	linux-kernel@...r.kernel.org, linux-arch@...r.kernel.org,
	mingo@...nel.org, tglx@...utronix.de,
	torvalds@...ux-foundation.org, akpm@...ux-foundation.org,
	hjl.tools@...il.com
Subject: Re: [PATCH 30/30] x32: Add x32 VDSO support

On Mon, Feb 20, 2012 at 7:58 PM, H. Peter Anvin <hpa@...or.com> wrote:
> On 02/20/2012 04:12 PM, Andy Lutomirski wrote:
>>
>> Would it make sense to remove the non-__vdso-prefixed weak symbols?
>> AFAICT they are somewhere between useless (because the __vdso symbols
>> are unambiguous), confusing (has anyone not read this and said "huh?"),
>> and wrong (they are not interchangeable with glibc's symbols as they
>> return different values).
>>
>> We're stuck with them on x86-64, but x32 is new and has no
>> backwards-compatibility issues.
>>
>
> What about non-glibc?

IMO non-glibc users should just call __vdso_clock_gettime, etc.
Currently, code like:

if (clock_gettime(whatever) == -1)
  handle_the_error();

is correct when linked against glibc but incorrect when linked
directly against the vdso.

--Andy
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