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Re: Release 2.26 - Next week ?
- From: Alan Modra <amodra at gmail dot com>
- To: "H.J. Lu" <hjl dot tools at gmail dot com>
- Cc: Tristan Gingold <gingold at adacore dot com>, Matthias Klose <doko at ubuntu dot com>, binutils <binutils at sourceware dot org>
- Date: Wed, 13 Jan 2016 16:48:24 +1030
- Subject: Re: Release 2.26 - Next week ?
- Authentication-results: sourceware.org; auth=none
- References: <C25FDD18-CD84-4630-9BCD-4B5E5CB057D6 at adacore dot com> <568FF162 dot 5000801 at ubuntu dot com> <828FEF00-284A-48C3-9395-2295167002EA at adacore dot com> <20160113010412 dot GB1270 at bubble dot grove dot modra dot org> <CAMe9rOpPPFuAwR-vif32KvDnjHRy5p4ushrvhrVso43681E+3Q at mail dot gmail dot com> <20160113015844 dot GC1270 at bubble dot grove dot modra dot org> <CAMe9rOqyLdTz5FiiMVTukDnQwby+Kx_wzmHtWtNu6n3ZOXfEDA at mail dot gmail dot com> <20160113034534 dot GD1270 at bubble dot grove dot modra dot org> <CAMe9rOrOaGWKS7me-v8AqUPKpKg=JxHcFdePBFPVtOEkKXGiuw at mail dot gmail dot com>
On Tue, Jan 12, 2016 at 09:08:33PM -0800, H.J. Lu wrote:
> Is __crc_TOC exported? If not, should it be exported? Is it referenced
> by kernel modules? If not, why does it matter?
When CONFIG_MODVERSONS is enabled, kernel symbols exported for modules
have an associated CRC. As part of the kernel build process,
__crc_<symbol> is used to set up a "__versions" section containing a
table of (CRC,symbol) pairs. Without __crc_TOC. present, no
__versions entry is set up for ".TOC.", and so modules that reference
".TOC." fail the CRC check that is supposed to ensure that a module
matches the running kernel.
Arguably, it is a kernel bug for __crc_TOC. to be undefined and of
value zero, but that's beside the point. The kernel build process
worked before, and as PR19421 illustrates the mere presense of an
undefined symbol conveys information. Removing them may break more
than just the ppc64le Linux kernel with CONFIG_MODVERSIONS on and
CONFIG_RELOCATABLE off.
The important question is: Was PR4317 just cosmetic?
--
Alan Modra
Australia Development Lab, IBM